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Sample records for cat carotid body

  1. Chronic hyperoxic effects on cat carotid body catecholamines and structure.

    PubMed

    Mokashi, A; Di Guilio, C; Morelli, L; Lahiri, S

    1994-06-01

    To account for the loss of O2 chemoreception in the cat carotid body during chronic hyperoxia, we studied the putative neurotransmitter correlates. Also, we studied the structural aspect of the carotid body tissues. We found that catecholamine concentrations increased and that the densecored vesicles in the glomus cells were not depleted, indicating that a lack of transmitters was not the cause for the loss of O2 chemoreception.

  2. Dual effects of nitric oxide on cat carotid body chemoreception.

    PubMed

    Iturriaga, R; Villanueva, S; Mosqueira, M

    2000-09-01

    We studied the effects of nitric oxide (NO) released by NO donors on cat carotid body (CB) chemosensory activity during normoxia and hypoxia. CBs excised from pentobarbital sodium-anaesthetized cats were perfused with Tyrode at 38 degrees C and pH 7.40. The frequency of chemosensory discharges (f(x)) was recorded from the carotid sinus nerve, and changes of NO concentration were measured by a chronoamperometric technique, with NO-selective carbon-fiber microelectrodes inserted in the CB. During steady chemosensory excitation induced by hypoxia, bolus injections of NO (DeltaNO = 0. 5-12 microM), released by S-nitroso-N-acetylpenicillamine (SNAP) and 6-(2-hydroxy-1-methyl-nitrosohydrazino)-N-methyl-1-hexanamine++ + (NOC-9), transiently reduced f(x) in a dose-dependent manner. However, during normoxia, the same concentration of NO (DeltaNO = 0. 5-13 microM) released by the NO donors increased f(x) in a dose-dependent manner. The present results show a dual effect of NO on CB chemoreception that is dependent on the PO(2) levels. During hypoxia, NO is predominantly an inhibitor of chemoreception, whereas, in normoxia, NO increased f(x). The mechanisms by which NO produces chemosensory excitation during normoxia remain to be determined.

  3. Modulatory effects of histamine on cat carotid body chemoreception.

    PubMed

    Del Rio, Rodrigo; Moya, Esteban A; Koenig, Cecilia S; Fujiwara, Kunio; Alcayaga, Julio; Iturriaga, Rodrigo

    2008-12-31

    Histamine has been proposed to be an excitatory transmitter between the carotid body (CB) chemoreceptor (glomus) cells and petrosal ganglion (PG) neurons. The histamine biosynthetic pathway, its storage and release, as well as the presence of histamine H1, H2 and H3 receptors have been found in the CB. However, there is only indirect evidence showing the presence of histamine in glomus cells, or weather its application produces chemosensory excitation. Thus, we studied the histamine immunocytochemical localization in the cat CB, and the effects of histamine, and H1, H2 and H3 receptor blockers on carotid sinus nerve (CSN) discharge, using CB and PG preparations in vitro. We found histamine immunoreactivity in dense-cored vesicles of glomus cells. Histamine induced dose-dependent increases in CSN discharge in the CB, but not in the PG. The H1-antagonist pyrilamine reduced the CB responses induced by histamine, the H2-antagonists cimetidine and ranitidine had no effect, while the H3-antagonist thioperamide enhanced histamine-induced responses. Present data suggests that histamine plays an excitatory modulatory role in the generation of cat CB chemosensory activity.

  4. Efferent inhibition of carotid body chemoreception in chronically hypoxic cats.

    PubMed

    Lahiri, S; Smatresk, N; Pokorski, M; Barnard, P; Mokashi, A

    1983-11-01

    The effects of chronic hypoxia on carotid chemoreceptor afferent activity before and after sectioning the carotid sinus nerves (CSN) were studied in cats exposed to 10% O2 for 21-49 days in a chamber at sea level. For comparison, chronically normoxic cats at sea level were also studied. The cats were anesthetized, paucifiber preparation for the measurement of carotid chemosensory activity from a small slip of CSN was made, and their steady-state responses to 4-5 levels of arterial pressure of O2 (PaO2) at a constant PaCO2 and to 3-4 levels of PaCO2 in hyperoxia were measured before and after sectioning the CSN. The chemosensory response to hypoxia in the cats with intact CSN after chronic exposure to hypoxia was not reduced relative to the cats that breathed room air at sea level. Sectioning the CSN significantly augmented the chemosensory responses to hypoxia in all the chronically hypoxic but not significantly in the normoxic cats. The responses to moderate hypercapnia during hyperoxia were not significantly changed by cutting the CSN in either group. We conclude that there is a significant CSN efferent inhibition of chemosensory activity due to chronic hypoxia in the cat. This implies that without the efferent inhibition the hypoxic chemosensitivity is increased by chronic hypoxia.

  5. Carbonic anhydrase and chemoreception in the cat carotid body.

    PubMed

    Iturriaga, R; Lahiri, S; Mokashi, A

    1991-10-01

    To test the hypothesis that CO2 and O2 chemoreception in the carotid body (CB) may depend on its carbonic anhydrase (CA) activity, we used an in vitro cat CB preparation and studied the effects of methazolamide, a permeable CA inhibitor (pK 7.3), on the chemosensory responses to CO2, O2, and nicotine. The isolated CB was perfused and superfused with Tyrode solution, free of CO2-HCO3-, at 36.0 +/- 0.5 degrees C. The frequency of chemosensory discharges was recorded from the whole carotid sinus nerve. The responses to bolus injections (0.3-0.5 ml) of Tyrode solution equilibrated with PCO2 of 38-110 Torr, switching from HEPES to CO2-HCO3- Tyrode (PCO2 = 25-60 Torr) for about 3 min, hypoxic Tyrode (PO2 = 25-30 Torr) for 2-8 min, perfusate flow interruptions for approximately 4 min, and bolus injections of nicotine (4 nmol) were studied before, during, and after perfusion (30-45 min) with methazolamide (42.4 microM). Methazolamide reversibly inhibited, delayed, and reduced the responses to transient CO2 stimulus, diminished the onset of but not the late response to prolonged CO2 stimulus, and delayed but did not decrease the responses to hypoxia and perfusate interruption. The response to nicotine did not change. The results indicated that CA in the glomus cells played a crucial role primarily in the speed and magnitude of the initial response to CO2 stimulus and indirectly influenced O2 chemoreception. These effects were upstream from the nicotine receptor-mediated sensory response.

  6. Anion exchanger and chloride channel in cat carotid body chemotransduction.

    PubMed

    Iturriaga, R; Mokashi, A; Lahiri, S

    1998-05-28

    In order to test the hypothesis that carotid body (CB) chemoreception depends on the functions of anion channels and HCO3-/Cl- exchangers, we studied the effects of the anion channel blocker anthracene-9-carboxylic acid (9-ANC), the carbonic anhydrase inhibitor methazolamide, and the HCO3-/Cl- exchanger blocker 4,4 diisothiocyanatostilbene-2-2'disulfonic acid (DIDS) on the chemosensory discharges of cat CB, perfused-superfused in vitro at 36.5 +/- 0.5 degrees C, with a modified Tyrode solution. The chemosensory responses to hypoxia (PO2 approximately 50 Torr), hypercapnia (PCO2 approximately 60 Torr, pH = 7.10), nicotine (2-4 nmol) and NaCN (20-40 nmol) were recorded. 9-ANC (2 microM) and DIDS (10 microM) decreased the chemosensory baseline activity, and eliminated the initial peak responses to hypercapnia and hypoxia and increased the time to achieve it. Methazolamide (0.13 mM) did not alter the effect of 9-ANC. The steady state responses to hypoxia and hypercapnia were not diminished after 9-ANC but DIDS lowered the responses. Responses to NaCN effects were all diminished but those to nicotine were not affected. The results suggest that the functions of anion channels and HCO3-/Cl- exchangers are important for the resting dischargers and for the fast responses to hypoxia and hypercapnia.

  7. Effects of naloxone on carotid body chemoreception and ventilation in the cat.

    PubMed

    Pokorski, M; Lahiri, S

    1981-12-01

    The effects of intravenous injection of naloxone (0.4 mg.kg-1), an opiate antagonist, on the responses of carotid body chemoreceptor discharge and ventilation to steady-state levels of hypoxia and hypercapnia were investigated in 12 anesthesized cats. After naloxone, carotid chemoreceptor response to hypoxia (PaO2 60--30 Torr) was enhanced, a finding that suggested that the endogenous enkephalin-like peptide present in the carotid body inhibits carotid chemoreceptors. This reasoning is supported by the observation that close intra-arterial injection of met-enkephalin inhibits carotid chemoreceptors and that the effect is blocked by naloxone. After naloxone, ventilation was stimulated even in the absence of a significant stimulation of carotid chemoreceptors during hyperoxia, indicating that ventilation is normally suppressed by endogenous opiates in the central nervous system, an effect disinhibited by naloxone. Also, the ventilatory effect of the peripheral chemoreceptor input was augmented after naloxone.

  8. Cat carotid body chemoreceptor responses before and after nicotine receptor blockade with alpha-bungarotoxin.

    PubMed

    Mulligan, E; Lahiri, S

    1987-01-01

    The nature of nicotine receptors in the carotid body was studied in anesthetized, paralyzed and artificially ventilated cats. Chemoreceptor discharge in single or few-fiber preparations of the carotid sinus nerve was measured during isocapnic hypoxia, hyperoxic hypercapnia and in response to nicotine injections before and after administration of alpha-bungarotoxin (10 cats) and after alpha-bungarotoxin plus mecamylamine (7 cats) which binds to neuromuscular-type nicotine cholinergic receptors. alpha-Bungarotoxin caused a slight enhancement of the chemoreceptor response to hypoxia without affecting the chemoreceptor stimulation by nicotine. Mecamylamine (1-5 mg, i.v.), a ganglionic-type nicotinic receptor blocker, had no further effect on the response to hypoxia while it completely abolished the chemoreceptor stimulation by nicotine. Thus the nicotinic receptors in the cat carotid body which elicit excitation of chemosensory fibers appear to be of the ganglionic-type. Blockade of neuromuscular and ganglionic types of nicotinic receptors in the carotid body by alpha-bungarotoxin and mecamylamine does not attenuate the chemosensory responses to either hypoxia or hypercapnia. These nicotinic receptors therefore, do not appear to play an essential role in hypoxic or hypercapnic chemoreception in the cat carotid body.

  9. Aortic and carotid body chemoreception in prolonged hyperoxia in the cat.

    PubMed

    Mokashi, A; Lahiri, S

    1991-11-01

    Carotid body chemosensory response to hypoxia is attenuated as a result of prolonged normobaric hyperoxia (NH) in the cat. The effect of NH is likely to be due to high cellular PO2 and O2-related free radicals. Accordingly, the effect would be less if O2 delivery to the chemoreceptor tissue could be compromised. The aortic bodies, which appear to have less of a circulatory O2 delivery, as suggested by their vigorous responses to a slight compromise of O2 flow compared with those of the carotid body, could provide a suitable testing material for the hypothesis. We tested the hypothesis by studying both aortic and carotid body chemoreceptors in the same cats (n = 6) which were exposed to nearly 100% O2 for about 60 h. These chemoreceptor organs were also studied in 6 control cats which were maintained in room air at sea-level. The cats were anesthetized and their carotid and aortic chemosensory fibers were identified by the usual procedure, and their responses to hypoxia and hypercapnia and to bolus injections (i.v.) of cyanide and nicotine were measured. In the NH cats, the carotid but not aortic chemosensory responses to hypoxia and cyanide were attenuated and to hypercapnia (both onset and steady state) augmented. The aortic chemoreceptors were stimulated by hypoxia, hypercapnia, cyanide and nicotine both in the NH and the control cats similarly. The results support the hypothesis that it is presumably a higher tissue blood flow and hence a higher concentration of O2-related free radicals which ultimately led to the specific attenuation of O2 chemoreception in the carotid body.

  10. Evidence for two types of nicotinic receptors in the cat carotid body chemoreceptor cells.

    PubMed

    Obeso, A; Gómez-Niño, M A; Almaraz, L; Dinger, B; Fidone, S; González, C

    1997-04-18

    Current concepts on the location and functional significance of nicotinic receptors in the carotid body rest on alpha-bungarotoxin binding and autoradiographic studies. Using an in vitro preparation of the cat carotid body whose catecholamine deposits have been labeled by prior incubation with the tritiated natural precursor [3H]tyrosine, we have found that nicotine induces release of [3H]catecholamines in a dose-dependent manner (IC50 = 9.81 microM). We also found that mecamylamine (50 microM) completely abolished the nicotine-induced release, while alpha-bungarotoxin (100 nM; approximately 20 times its binding Kd) only reduced the release by 56%. These findings indicate that chemoreceptor cells, and perhaps other carotid body structures, contain nicotinic receptors that are not sensitive to alpha-bungarotoxin and force a revision of the current concepts on cholinergic mechanisms in the carotid body chemoreception.

  11. Occurrence of neutral endopeptidase activity in the cat carotid body and its significance in chemoreception.

    PubMed

    Kumar, G K; Runold, M; Ghai, R D; Cherniack, N S; Prabhakar, N R

    1990-05-28

    The carotid body contains both tachykinins and enkephalins. Neutral endopeptidase (NEP, E.C. 3.4.24.11), has been suggested to involve in the metabolism of these neuropeptides in several organs. In the present study we determined neutral endopeptidase activity of the cat carotid body and assessed its significance in chemoreception. The cytosolic and membrane fractions of the carotid body contained NEP-like activity whereas it occurred only in the membrane fractions of the superior cervical and the nodose ganglia. Phosphoramidon, thiorphan and metal ion chelators inhibited NEP-like activity of all the 3 tissues studied; other protease inhibitors, however, were ineffective. Close carotid body administration of phosphoramidon significantly potentiated the carotid body response to low PO2 but not to hypercapnia. The enhanced response to hypoxia following phosphoramidon was further augmented by naloxone, an enkephalin antagonist. These results demonstrate that the glomus tissue contains detectable amounts of NEP-like activity and its inhibition selectively affects the hypoxic response of the carotid body.

  12. Optical measurements of the dependence of chemoreception on oxygen pressure in the cat carotid body.

    PubMed

    Rumsey, W L; Iturriaga, R; Spergel, D; Lahiri, S; Wilson, D F

    1991-10-01

    The relationship between oxygen pressure (PO2) in the carotid body and carotid sinus nerve discharge was evaluated in the isolated perfused/superfused cat carotid body using the oxygen-dependent quenching of phosphorescence. Images of phosphorescence intensity arising from Pd-coproporphyrin within the microcirculation of the carotid body provided measurements of intravascular PO2. These measurements were substantiated by determining phosphorescence life-time. The carotid body was perfused in the isolated state via the common carotid artery with N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid-buffered Tyrode solution, pH 7.4, at a constant pressure of 80 mmHg. Superfusion was maintained with similar media equilibrated with 100% argon. PO2 in the exchange vessels was markedly less than that in the perfusate entering the carotid artery, 23 +/- 3 and 45 +/- 3 Torr for normoxic (111 +/- 15 Torr) and hyperoxic (345 +/- 72 Torr) perfusates, respectively. Chemosensory discharge rose slowly in response to a brief interruption of perfusate flow as PO2 steadily declined from either of these capillary PO2 values to approximately 10 Torr. Between approximately 10 and 3 Torr, chemosensory discharge increased strikingly, concomitant with an enhanced rate of oxygen disappearance, from -36 +/- 4 to -69 +/- 13 (92% change) and -28 +/- 3 to -48 +/- 3 (71% change) Torr/s for normoxic and hyperoxic perfusates, respectively. As PO2 fell below approximately 3 Torr, oxygen disappearance slowed and neural activity decayed. Thus the relationships between microvascular PO2 and chemosensory discharge and between oxygen disappearance and neural discharge suggest that oxygen metabolism in the carotid body determines the expression of oxygen chemoreception.

  13. Hydrogen sulfide activates the carotid body chemoreceptors in cat, rabbit and rat ex vivo preparations.

    PubMed

    Jiao, Yingfu; Li, Qian; Sun, Biying; Zhang, Guohua; Rong, Weifang

    2015-03-01

    We and others previously reported experimental evidence suggesting an important role for hydrogen sulfide (H2S) in oxygen sensing in murine carotid body chemoreceptors. More recent data implicated abnormal H2S-mediated chemoreceptor signaling in pathological conditions such as chronic heart failure and hypertension. However, the idea of H2S as a mediator of oxygen-sensing in chemoreceptors has been challenged. In particular, it was shown that exogenous H2S inhibited the release of neurotransmitters (ACh and ATP) from the cat carotid body, raising the possibility that there exists significant species difference in H2S-mediated signaling in chemoreceptors. This study was designed specifically to determine the effect of H2S on chemoreceptors in different species. We conducted multiunit extracellular recordings of the sinus nerve in the ex vivo carotid body preparation taken from the rat, the cat and the rabbit. As observed in the mouse carotid body, H2S donors (NaHS or Na2S) evoked qualitatively similar excitatory responses of the afferent sinus nerves of the species studied here. The excitatory effects of the H2S donors were concentration-dependent and reversible. The sinus nerve responses to H2S donors were prevented by blockade of the transmission between type I cells and the afferent terminals, as was the response to hypoxia. These results demonstrate that exogenous H2S exerts qualitatively similar excitatory effects on chemoreceptor afferents of different species. The role of endogenous H2S-mediated signaling in carotid body function in different species awaits further investigation.

  14. Effects of nitric oxide gas on cat carotid body chemosensory response to hypoxia.

    PubMed

    Iturriaga, R; Mosqueira, M; Villanueva, S

    2000-02-14

    It has been proposed that nitric oxide (NO) is an inhibitory modulator of carotid body (CB) chemoreception to hypoxia. However, the effects of NO gas on carotid chemoreception have not been tested yet. The role played by NO has been revealed by the use of pharmacological tools (i.e., NO donors and NO synthase inhibitors). Here, we studied the effects of NO gas (25 ppm in N(2)) on the chemosensory response to hypoxia (PO(2) approximately 30 Torr) in the cat CB perfused in vitro. During steady hypoxic chemoreceptor excitation, bolus injections or perfusion of Tyrode equilibrated with NO reduced the increased frequency of carotid chemosensory discharges (f(x)). Perfusion for 2 min of Tyrode equilibrated with NO also reduced the rate of the rise of the chemosensory response, as well as the maximal amplitude, as compared with the normal chemosensory response to hypoxia. Present results provide direct evidence that NO gas is an inhibitory modulator of CB hypoxic chemoreception.

  15. Endothelins in the cat petrosal ganglion and carotid body: effects and immunolocalization.

    PubMed

    Rey, Sergio; Del Rio, Rodrigo; Alcayaga, Julio; Iturriaga, Rodrigo

    2006-01-19

    In response to hypoxia, chemoreceptor cells of the carotid body (CB) release transmitters, which acting on the petrosal ganglion (PG) neuron terminals, increase the chemoafferent discharge. Additionally, vasoactive molecules produced within the CB may modulate hypoxic chemoreception by controlling blood flow and tissue PO2. Endothelin-1 (ET-1) increases basal CB chemosensory discharges in situ, probably due to its vasoconstrictor action. However, the actions of ET-1 on PG neurons or its expression in the PG are not known. Using immunohistochemistry, we found that endothelin-like peptides are expressed in the cat PG and CB under normoxic conditions. Exogenous applications of ET-1 increased the chemosensory activity in the vascularly perfused CB but were ineffective on either the CB or PG superfused preparations, both of which are devoid of vascular control. Thus, our data indicate that the excitatory effect of ET-1 in the carotid chemoreceptor system appears to be mainly due to a vasoconstrictor effect in the CB blood vessels.

  16. CO reveals dual mechanisms of O2 chemoreception in the cat carotid body.

    PubMed

    Lahiri, S; Iturriaga, R; Mokashi, A; Ray, D K; Chugh, D

    1993-11-01

    The hypothesis that CO-binding pigments in the carotid body participate in O2 chemoreception was tested. The chemosensory nerve discharges of cat carotid body perfused and superfused in vitro at 36-37 degrees C with cell-free solution containing CO2-HCO3- (pH approximately equal to 7.39) were recorded to monitor O2 chemoreception. Several levels of PCO (60-550 Torr) at two levels of PO2 (50 Torr-140 Torr) were used. With high PCO of 500-550 Torr at any PO2 the discharge rate peaked promptly but the effect was significantly less than that to hypoxia. At any stage of the CO effect, exposure to light promptly attenuated or eliminated the response, as if the stimulatory effect of hypoxia was absent. Lower PCO of 60-70 Torr attenuated the response to hypoxia which was not suppressed by light. PCO of 140 Torr also attenuated the response to hypoxia and made the activity partially photolabile. During high PCO exposure the excitatory response to cyanide but not to nicotine was attenuated, consistent with the idea that the effects of nicotine are downstream from those of CO. Both inhibitory and excitatory effects of CO were promptly reversible. The results indicate that two types of CO-binding chromophores participate in O2 chemoreception in the carotid body.

  17. Contribution of in vivo microvascular PO2 in the cat carotid body chemotransduction.

    PubMed

    Lahiri, S; Rumsey, W L; Wilson, D F; Iturriaga, R

    1993-09-01

    To understand the interplay between microcirculatory control and carotid body (CB) function, we simultaneously measured carotid body microvascular PO2 (CBM PO2) and chemosensory activity in the cat in vivo under several experimental conditions. Cats were anesthetized with pentobarbital sodium, paralyzed, and artificially ventilated. CBs were exposed, and steady-state CBM PO2 was measured by the O2-dependent quenching of the phosphorescence of Pd-meso-tetra-(4-carboxyphenyl)porphine, which was administered intravenously. A few fibers of the carotid sinus nerve were used to record chemosensory discharges. At arterial PO2 (PaO2) of 103.4 +/- 4.1 Torr, CBM PO2 was 52.5 +/- 3.6 Torr (n = 9). Graded lowering of PaO2 from 160 to 50 Torr resulted in nearly proportional decreases in CBM PO2, but at lower PaO2 the decrease in CBM PO2 became more substantial. As PaO2 decreased, chemosensory discharge increased in parallel with CBM PO2. Hypercapnia and hypocapnia did not significantly change the relationship between PaO2 and CBM PO2, although the chemosensory discharge responded significantly. CBM PO2 and chemosensory discharge were not affected by hemorrhagic hypotension until arterial blood pressure fell below approximately 50 Torr and then CBM PO2 decreased and chemosensory discharge increased. The lack of a significant effect of hemorrhagic hypotension indicated that O2 delivery to CB was almost independent of the systemic blood pressure. Taken together, the observations suggest that CB microcirculation and PO2 are subject to control by intrinsic mechanisms and that CBM PO2 is compatible with oxidative metabolism playing a role in O2 chemoreception during hypoxia.

  18. Respiratory modulation of carotid and aortic body reflex left ventricular inotropic responses in the cat.

    PubMed

    Daly, M D; Jones, J F

    1998-06-15

    1. The reflex changes in the inotropic state of the left ventricle, measured as the dP/dt max (maximum rate of change of pressure), occurring in response to selective stimulation of the carotid and aortic body chemoreceptors by sodium cyanide, were studied in the cat anaesthetized with a mixture of chloralose and urethane. 2. The animals were artificially ventilated with an open pneumothorax. The heart rate and mean arterial blood pressure were maintained constant. 3. With on-going central respiratory activity, stimulation of the carotid bodies caused an increase in respiratory movements. Variable changes in left ventricular dP/dt max occurred, the predominant response being an increase. The mean change was 8.3 +/- 2.9 % from a control value of 6850 +/- 450 mmHg s-1. Stimulation of the aortic bodies resulted in a smaller increase in respiration or no effect, but a significant increase occurred in left ventricular dP/dt max of 19.6 +/- 2.9 % from a control value of 6136 +/- 228 mmHg s-1. No significant changes in left ventricular end-diastolic pressure occurred in response to stimulation of either group of chemoreceptors. 4. Tests of chemoreceptor stimulations were repeated during temporary suppression of the secondary respiratory mechanisms: the central respiratory drive was suppressed reflexly by electrical stimulation of the central cut ends of both superior laryngeal nerves and lung stretch afferent activity was minimized by stopping artificial respiration. Carotid body stimulation again evoked variable responses, the predominant now being a reduction in left ventricular dP/dt max of 3.1 % from a control value of 5720 +/- 320 mmHg s-1, which was significantly different to that occurring during on-going spontaneous respiration. Aortic body stimulation caused an increase in left ventricular dP/dt max similar to the response during on-going spontaneous respiration. 5. The positive inotropic responses were mediated via the sympathetic nervous system, as indicated by

  19. Cat carotid body oxygen metabolism and chemoreception described by a two-cytochrome model.

    PubMed

    Nair, P K; Buerk, D G; Whalen, W J

    1986-02-01

    We have analyzed O2 disappearance curves (DCs) in cat carotid bodies (CBs) measured with our O2 microelectrode, after stopping flow of either blood (108 DCs in 12 cats) or a hemoglobin-free (Locke) perfusion solution (35 DCs in 6 cats). Prior to occlusion, the mean tissue PO2 levels were 74.5 +/- 2.8 (SE) Torr in blood-perfused CBs and 103.4 +/- 2.6 in Locke-perfused CBs. The O2 consumption rates (VO2) determined from the initial 3 s of the DCs were 1.46 +/- 0.08 and 1.50 +/- 0.10 (SE) ml O2 . 100 g-1 . min-1, respectively, for the blood-perfused and Locke-perfused CBs. The change in total sinus nerve activity from the CB was also measured following stopped flow. The nerve activity began to increase immediately, providing further evidence that classic hypoxia is not the mechanism of chemoreceptor discharge. However, about two-thirds of the increased activity in blood-perfused CBs occurred after tissue PO2 levels fell below 20 Torr. As the CB tissue PO2 decreased, the O2 disappearance rate (-dPO2/dt) also decreased for both experimental conditions, indicating that the CB VO2 varies with O2 concentration. The increase in nerve discharge and O2 disappearance rate can be interpreted by a two-cytochrome model for O2 metabolism, with both high and low affinities.

  20. Effect of hypoxia and hypercapnia on catecholamine content in cat carotid body.

    PubMed

    Fitzgerald, R S; Garger, P; Hauer, M C; Raff, H; Fechter, L

    1983-05-01

    The purpose of this study was to determine the content of catecholamines (CA) in the cat carotid body before and after 0.5 h exposures to normoxic normocapnia [arterial O2 partial pressure (Pao2) 126 +/- 28 Torr, arterial CO2 partial pressure (Paco2) 36.4 +/- 1.5 Torr], hypoxic normocapnia (Pao2 25 +/- 3 Torr, Paco2 36.7 +/- 3.3 Torr), and normoxic hypercapnia (Pao2 132 +/- 13 Torr, Paco2 = 98.2 +/- 7.6 Torr). CA synthesis was blocked using alpha-methylparatyrosine methyl ester (AMPT) prior to alterations in the inspired air. There was a significant decrease in carotid body content of dopamine (DA), norepinephrine (NE), and epinephrine (E) 1 h after AMPT administration. Analysis of variance and Duncan new multiple range procedures revealed that during the subsequent 0.5-h exposures to normoxia, hypoxia, or hypercapnia, only the decrease in DA during hypoxia was significantly greater than that during normoxia; the loss during hypercapnia was not. The decreases in NE during the three exposures were indistinguishable among themselves as were the decreases in E. The decrease in CA content is probably attributable to increased release. The data reveal that the release of CAs during the chemoreception of hypoxia is different from that during the chemoreception of hypercapnia and support the concept of different mechanisms for the chemoreception of hypoxia and hypercapnia.

  1. Stimulus interaction between CO and CO2 in the cat carotid body chemoreception.

    PubMed

    Osanai, S; Chugh, D K; Mokashi, A; Lahiri, S

    1996-03-04

    Since high PCO in the dark works like hypoxia in the carotid body chemoreceptors and since hypoxia shows a stimulus interaction with CO2, it is hypothesized that high PCO will show a similar interaction with PCO2 in the chemosensory excitation in the dark. We tested the hypothesis using cat carotid body perfused and superfused in vitro with Po2 of about 100 Torr. In one series, the chemosensory discharges were tested at three levels of PCO2 at high PCO of 500 Torr in the absence and presence of light. In the dark, normocapnia (PCO2 approximately 30 Torr) with high PCO promptly stimulated the sensory discharges to a peak, subsiding to a lower level. In hypocapnia (PCO2 approximately 18 Torr) with high PCO, all phases of activities were significantly lower than those of normocapnia, showing stimulus interaction. Hypercapnia saturated the activity with high PCO and seems to preclude a clear demonstration of stimulus interaction. In another series, an intermediate level of PCO (approximately 150 Torr), which showed a half-maximal activity in normoxia, showed a clear interaction with hypercapnia in the dark. With high PCO, bright light promptly reduced the activity to baseline at all PCO2 levels. This then increased somewhat to a steady-state. Withdrawal of the light was followed by a sharp rise in the activity to a peak which then fell to a somewhat lower level of steady-state. The peak discharge rate in the presence of light did not differ significantly from those of PCO2 alone.

  2. Intracellular pH and oxygen chemoreception in the cat carotid body in vitro.

    PubMed

    Iturriaga, R; Rumsey, W L; Lahiri, S; Spergel, D; Wilson, D F

    1992-06-01

    To test the hypothesis that O2 chemoreception in the carotid body (CB) is mediated by cellular acidosis, we simultaneously measured responses of the chemosensory and intracellular pH (pHi) to agents that are known to change pHi and studied the effects of hypoxia and ischemia on these variables in the cat CB. The CB was perfused and superfused in vitro with a modified Tyrode's solution at 36.0 +/- 0.5 degrees C with or without CO2-HCO3- (pH 7.40) and equilibrated at a given PO2. Chemosensory discharges were recorded from the whole carotid sinus nerve. To measure pHi changes, the CB was loaded with the pH-sensitive indicator 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein, and the fluorescence (excitation 420-490 nm, emission greater than 515 nm) was detected by an intensified charged coupled device camera with an epifluorescence macroscope. Boluses of Tyrode's solution (0.5 ml, free of CO2-HCO3-) containing sodium acetate or NH4Cl prolonged perfusion of acid Tyrode's solution (pH 7.20-6.50), and boluses of Tyrode's solution with CO2-HCO3- were used. A decrease of fluorescence indicated pHi turning acid, and an increase of fluorescence indicated a change in alkaline pHi. Chemosensory activity varied inversely with the fluorescence change after application of these agents. Interruption of perfusate flow or application of hypoxic perfusate resulted in large increases in chemosensory discharge without any change in the fluorescence. The results indicated that chemosensory responses to brief ischemia and hypoxia were not mediated by a fall of pHi of CB cells, whereas those to CO2 and extracellular acidity were associated with decreases in pHi.

  3. Potential role of H2O2 in chemoreception in the cat carotid body.

    PubMed

    Osanai, S; Mokashi, A; Rozanov, C; Buerk, D G; Lahiri, S

    1997-03-19

    The hypothesis that H2O2 plays a critical role in hypoxic chemoreception in the cat carotid body (CB) was tested using a perfused-superfused preparation in vitro, measuring chemosensory discharge and CB tissue PO2 (PtiO2). According to the hypothesis NADPH mediated, PO2 dependent increase in H2O2 production would hyperpolarize the glomus cell, decreasing the chemosensory discharge. Thus, lactate and aminotriazole which would increase H2O2 concentration, would decrease the chemosensory discharge during hypoxia. However, 2.5-5.0 mM lactate and 25 mM aminotriazole did not diminish the hypoxic response. But, 2.5 mM lactate decreased the chemosensory discharge during normoxia which can be explained by an increase of CB PtiO2. Diethyldithiocarbamic acid (5 mM), which blocks the conversion of superoxide to H2O2, also diminished the chemosensory discharge, presumably due to an increased CB PtiO2. Menadione (increasing H2O2) and t-butyl hydroperoxide irreversibly decreased the chemosensory discharge, and the data are not useful. H2O2 increased the PO2 of the perfusate, and therefore could not be tested against PO2. Thus, perturbation of endogenous or exogenous H2O2 did not provide any evidence for its critical role in O2 chemoreception.

  4. THE IMPACT OF HYDROGEN SULFIDE (H2S) ON NEUROTRANSMITTER RELEASE FROM THE CAT CAROTID BODY

    PubMed Central

    Fitzgerald, Robert S.; Shirahata, Machiko; Chang, Irene; Kostuk, Eric; Kiihl, Samara

    2011-01-01

    Do cat carotid bodies (CBs) increase their release of acetylcholine and ATP in response to H2S? Two CBs, incubated in a Krebs Ringer bicarbonate solution at 37° C, exhibited a normal response to hypoxia -- increased release of acetylcholine (ACh) and ATP. They were challenged with several concentrations of Na2S, an H2S donor. H2S, a new gasotransmitter, is reported to open KATP channels. Under normoxic conditions the CBs reduced their release of ACh and ATP below control values. They responded identically to pinacidil, a well-known KATP channel opener. CB glomus cells exhibited a positive immunohistochemical signal for cystathione-β-synthetase, a H2S synthesizing enzyme, and for a subunit of the KATP channel. The data suggest that Na2S may have opened the glomus cells’ KATP channels, hyperpolarizing the cells, thus reducing their tonic release of ACh and ATP. Since during hypoxia H2S levels rise, the glomus cells responding very actively to hypoxia may be protected from over-exertion by the H2S opening of the KATP channels. PMID:21292043

  5. Trigeminal and carotid body inputs controlling vascular resistance in muscle during post-contraction hyperaemia in cats

    PubMed Central

    de Burgh Daly, M; Cook, M N

    1999-01-01

    In anaesthetized cats, the effects of stimulation of the receptors in the nasal mucosa and carotid body chemoreceptors on vascular resistance in hindlimb skeletal muscle were studied to see whether the responses were the same in active as in resting muscle. The measurements of vascular resistance were taken, first, in resting muscle, and second, in the immediate post-contraction hyperaemic phase that followed a 30 s period of isometric contractions.Stimulation of the receptors in the nasal mucosa caused reflex apnoea and vasoconstriction in muscle. The latter response was attenuated when the test was repeated during post-contraction hyperaemia.Stimulations of the carotid bodies were made during a period of apnoea evoked reflexly by electrical stimulation of both superior laryngeal nerves. This apnoea prevented any effects of changes in respiration on the carotid body reflex vascular responses. Stimulation of the carotid bodies evoked hindlimb muscle vasoconstriction. In the post-contraction hyperaemic period, the response was reduced or abolished. A similar attenuation of the reflex vasoconstrictor responses occurred in decentralized muscles stimulated through their motor roots in the cauda equina.Evidence is presented that the attenuation of the vasoconstrictor responses evoked by the two reflexes is a phenomenon localized to the contracting muscles themselves resulting from an interaction between sympathetic neuronal activity and the local production of metabolites.The results are discussed in relation to the metabolic needs of tissues in relation to asphyxial defence mechanisms such as occur in the diving response. PMID:10050020

  6. Testing the metabolic hypothesis of O2 chemoreception in the cat carotid body in vitro.

    PubMed

    Buerk, D G; Iturriaga, R; Lahiri, S

    1994-03-01

    It is known that oligomycin reduces the oxidative phosphorylation high-energy state or high-energy intermediates by inhibiting the formation of ATP without directly inhibiting electron transport, whereas metabolic uncouplers dissipate the high-energy state without net production of ATP. The metabolic hypothesis for O2 chemoreception in the carotid body (CB) predicts that 1) oligomycin should diminish O2 consumption and attenuate O2 chemoreception and 2) uncouplers should reverse the effect of oligomycin by increasing O2 consumption without restoring O2 chemoreception. These predictions were tested by simultaneously measuring CB chemosensory discharge from the sinus nerve and the rate of tissue O2 disappearance (dPO2/dt) during interruption of perfusate flow in perfused-superfused cat CB preparations (n = 9). O2 consumption was calculated from dPO2/dt. Flow-interruption responses were measured before and after oligomycin (1-microgram bolus) and subsequently after dinitrophenol (50 microM). Chemosensory responses to bolus injections of hypercapnic Tyrode solution, cyanide, or nicotine were also tested periodically. Oligomycin diminished dPO2/dt from -2.67 +/- 0.30 to -2.02 +/- 0.19 (SE) Torr/s (P < 0.004, paired t test) and reduced the maximal sensory response from 196 +/- 43 to 124 +/- 12 impulses/s (P < 0.002, paired t test) while augmenting the initial response to CO2. Dinitrophenol reversed the metabolic depressant effect of oligomycin but further suppressed the chemosensory response. These results confirm the above predictions and strengthen the metabolic hypothesis for O2 chemoreception in the CB.

  7. Neural responses of the cat carotid and aortic bodies to hypercapnia and hypoxia.

    PubMed

    Fitzgerald, R S; Dehghani, G A

    1982-03-01

    The response (imp . s-1) of single- or few-fiber preparations from the carotid body (10 experiments) and the aortic body (5 experiments) to various levels of hypercapnia on different backgrounds of hypoxia were analyzed by two statistical techniques--analysis of variance and the Duncan's new multiple-range test. These analyses showed an initial statistically significant increase in the slope of the response to increasing arterial pressure of CO2 (PaCO2) as PaO2 fell. But the slope of the response to carbon dioxide later showed a clear tendency to become less; i.e., no significant increase in imp . s-1 when a PaCO2 rose (substantially) with normoxic (carotid body) and hypoxic (carotid and aortic bodies) backgrounds. The response of the aortic body to hypercapnia showed no statistically significant increase if the background was hyperoxia or normoxia. The characteristic of the chemoreceptor to become saturated in its response to carbon dioxide while still retaining its ability to respond to hypoxia suggests the possibility that at least some of the mechanisms involved in the chemoreception of hypoxia differ from those involved in the chemoreception of hypercapnia.

  8. Lipopolysaccharide-induced carotid body inflammation in cats: functional manifestations, histopathology and involvement of tumour necrosis factor-alpha.

    PubMed

    Fernández, Ricardo; González, Sergio; Rey, Sergio; Cortés, Paula P; Maisey, Kevin R; Reyes, Edison-Pablo; Larraín, Carolina; Zapata, Patricio

    2008-07-01

    In the absence of information on functional manifestations of carotid body (CB) inflammation, we studied an experimental model in which lipopolysaccharide (LPS) administration to pentobarbitone-anaesthetized cats was performed by topical application upon the CB surface or by intravenous infusion (endotoxaemia). The latter caused: (i) disorganization of CB glomoids, increased connective tissue, and rapid recruitment of polymorphonuclear cells into the vascular bed and parenchyma within 4 h; (ii) increased respiratory frequency and diminished ventilatory chemoreflex responses to brief hypoxia (breathing 100% N(2) for 10 s) and diminished ventilatory chemosensory drive (assessed by 100% O(2) tests) during normoxia and hypoxia; (iii) tachycardia, increased haematocrit and systemic hypotension in response to LPS i.v.; and (iv) increased basal frequency of carotid chemosensory discharges during normoxia, but no change in maximal chemoreceptor responses to brief hypoxic exposures. Lipopolysaccharide-induced tachypnoea was prevented by prior bilateral carotid neurotomy. Apoptosis was not observed in CBs from cats subjected to endotoxaemia. Searching for pro-inflammatory mediators, tumour necrosis factor-alpha (TNF-alpha) was localized by immunohistochemistry in glomus and endothelial cells; reverse transcriptase-polymerase chain reaction revealed that the CB expresses the mRNAs for both type-1 (TNF-R1) and type-2 TNF-alpha receptors (TNF-R2); Western blot confirmed a band of the size expected for TNF-R1; and histochemistry showed the presence of TNF-R1 in glomus cells and of TNF-R2 in endothelial cells. Experiments in vitro showed that the frequency of carotid nerve discharges recorded from CBs perfused and superfused under normoxic conditions was not significantly modified by TNF-alpha, but that the enhanced frequency of chemosensory discharges recorded along responses to hypoxic stimulation was transiently diminished in a dose-dependent manner by TNF-alpha injections

  9. Dopamine increases in cat carotid body during excitation by carbon monoxide: implications for a chromophore theory of chemoreception.

    PubMed

    Buerk, D G; Chugh, D K; Osanai, S; Mokashi, A; Lahiri, S

    1997-12-11

    Studies of dopamine (DA) release were conducted with 10 perfused/superfused cat carotid bodies using shallow recessed Nafion polymer-coated microsensors (tips approximately 5 microns). Simultaneous measurements of tissue DA and neuronal discharge (ND) from the sinus nerve were made after switching from normoxic, normocapnic control perfusate (20% O2, 5% CO2, balance N2) to a normoxic, normocapnic perfusate equilibrated with a high tension (> 550 Torr) of carbon monoxide (CO). When high PCO perfusate was delivered in the dark, ND increased from a baseline of 89 +/- 24 (SE) impulses/s, to a peak excitation of 374 +/- 44 impulses/s within 15-30 s. Excitation then diminished to a plateau of 281 +/- 36 impulses/s within 1-2 min. Both peak and plateau ND were significantly above baseline (P < 0.05). Average tissue DA values increased above basal levels by +7.2 +/- 1.0 and +5.6 +/- 0.6 microns, respectively, during the peak and plateau ND phases (P < 0.05). Bright light restored the chemosensory activity to baseline, but had no effect on DA. Both chemosensory excitation and tissue DA responses to high CO in the dark were diminished in 3 carotid bodies perfused with Ca(2+)-free solutions. Responses were reduced even further with Ca2+ chelator (EGTA) in the perfusate. The results suggest that the effect of high PCO on DA release and chemosensory excitation are dependent on Ca2+ in the media, but the two events are not coupled.

  10. Release of dopamine and chemoreceptor discharge induced by low pH and high PCO2 stimulation of the cat carotid body.

    PubMed Central

    Rigual, R; López-López, J R; Gonzalez, C

    1991-01-01

    1. Cat carotid bodies were incubated with the precursor [3H]tyrosine to label the catecholamine deposits and then mounted in a superfusion chamber which allowed simultaneous collection of the released [3H]dopamine (DA) and recording of action potentials from the carotid sinus nerve. 2. Low pH (7.2-6.6) superfusion of the carotid bodies for periods of 10 min produced a parallel increase in the release of [3H]DA and chemoreceptor discharge. 3. Carotid sinus nerve denervation of the carotid body 12-15 days prior to the experiments did not modify the release of [3H]DA elicited by low pH. 4. Superfusion of the carotid bodies with Ca(2+)-free, high-Mg2+ (1.6 mM) media reduced basal release of [3H]DA and chemoreceptor discharge by about 30%. Release evoked by low pH was reduced by 82%. Peak and average chemoreceptor discharge recorded in response to low pH were reduced by 28%. 5. Solutions containing weak acids (sodium acetate, 10 mM), adjusted at pH 7.4, elicited release of [3H]DA and increased chemoreceptor discharge. 6. With HCO3-CO2-buffered superfusion media, a reduction of bicarbonate to 5.6 mM (pH 6.8), an increase in CO2 to 20% (pH 6.8), or a simultaneous increase in CO2 to 20% and bicarbonate to 90 mM (pH 7.4), resulted in all cases in a corresponding increase in [3H]DA release and chemoreceptor discharge. The most effective stimulus was 20% CO2-pH 6.8 and the least effective 5% CO2-5.6 mM-HCO3-pH 6.8. 7. Inhibition of carbonic anhydrase with acetazolamide while perfusing the carotid bodies with a 20% CO2-equilibrated (pH 7.4) solution resulted in comparable reductions in the release of [3H]DA and chemoreceptor discharge. 8. It is concluded that the effective acidic stimulus at the carotid body chemoreceptors is an increase in hydrogen ion concentration in type I cells. It is also concluded that DA plays a critical role in the genesis of carotid sinus nerve discharges. PMID:1841956

  11. Effects of changes in chemoreceptor activity on extracellular K+ and Ca2+ activities in the cat carotid body.

    PubMed

    O'Regan, R G; Acker, H

    1988-04-05

    In anaesthetized, paralysed and artificially ventilated cats triple-barrelled ion-selective microelectrodes (ISMs) were inserted into the right carotid body in order to measure extracellular activities of K+ ([K+]o) and Ca2+ ([Ca2+]o) simultaneously. In 3 experiments a method involving iron deposition located the tips of the ISMs in the cellular islands of the organ. A thin cannula inserted into the right carotid artery (i.c.) via the lingual artery was used to infuse Ringer-Locke solutions (0.1-0.5 ml/min) containing either sodium cyanide (NaCN), acetylcholine (ACh) or dopamine (DA). Analysis of the effects of administration of NaCN (20-100 micrograms/min i.c.) showed that during this procedure [K+]o increased and [Ca2+]o decreased by mean values (+/- S.D.) of 0.99 +/- 0.82 and 0.22 +/- 0.06 mM respectively. During administration of ACh (20-50 micrograms/min i.c.) [K+]o increased and [Ca2+]o decreased respectively by mean values (+/- S.D.) of 3.18 +/- 3.0 and 0.31 +/- 0.14 mM. Decreases in [K+]o and [Ca2+]o by mean values (+/- S.D.) of 1.53 +/- 1.64 and 0.34 +/- 0.33 mM respectively were associated with administration of DA (20-50 micrograms/min i.c.). The predominant influences exerted by NaCN and ACh on chemoreceptor activity were excitatory whereas administration of DA caused either inhibition, excitation or a combination of these two effects. Stimulation of the sympathetic supply to the carotid body was associated with either increases, decreases or no reaction of chemosensory activity, [K+]o and [Ca2+]o. The changes in [K+]o associated with the various procedures may reflect the state of polarization within the chemoreceptor complex. Decreases in [Ca2+]o usually accompanied the performance of all procedures and may have resulted from an increased influx of this ion from the interstitial fluids into the cells for the purpose of provoking neurotransmitter release. However, the time course of the changes in [K+]o and [Ca2+]o were considerably slower in onset and

  12. Adrenergic mechanisms and chemoreception in the carotid body of the cat and rabbit.

    PubMed

    Folgering, H; Ponte, J; Sadig, T

    1982-04-01

    1. The effect of beta-adrenergic and dopaminergic agonists and antagonists on the chemoreceptor response to graded hypoxia and hypercapnia was tested in nineteen cats and ten rabbits anaesthetized either with chloralose-urethane or pentobarbitone sodium, paralysed with pancuronium bromide and artificially ventilated.2. The inhibitory action of dopamine was confirmed. The inhibition following intra-arterial bolus injection was blocked by haloperidol; dopamine then excited and this excitation was blocked with propranolol. Adrenaline or noradrenaline caused a transient inhibition followed by a marked excitation. The inhibition was blocked with haloperidol and the excitation blocked with propranolol or metoprolol. Isoprenaline excited without inhibition and this was blocked with propranolol or metoprolol.3. A novel finding was that the chemoreceptor response to hypoxia was markedly reduced or even abolished with propranolol or metoprolol. The response was enhanced with a constant infusion of isoprenaline, adrenaline or noradrenaline in proportion to the degree of hypoxia, an effect mimicked by raising CO(2). The chemoreceptor response to hypoxia was similarly enhanced by haloperidol and depressed by a constant infusion of dopamine in proportion to the degree of hypoxia.4. The effect of these drugs on the chemoreceptor response to hypercapnia was less constant. In the majority of tests the aminergic agonists and antagonists caused a parallel shift of the CO(2) response curves in the same direction as the O(2) response curves and by amounts proportional to the degree of hypoxia. In some tests these drugs caused a change in the slope of the CO(2) response curves but only if P(a, O2) was less than 60 mmHg.5. One interpretation of these results is that hypoxia exerts a presynaptic action, causing the release of noradrenaline and dopamine from Type I cells, and that these substances act upon aminergic receptors on the sensory fibre, causing a change in potential and

  13. Carotid Body Tumor.

    PubMed

    Bakshi, Satvinder S; Kumar T, Lokesh

    2017-08-14

    A 17 year old girl presented with a progressively increasing swelling in her neck since 9 months. On examination a2*3 cm, firm, pulsatile swelling was felt in the left anterior triangle. The CT scan of the mass was suggestive of a carotid body tumor and urinary cathecholamines were negative. The mass was excised completely.

  14. G proteins in carotid body chemoreception.

    PubMed

    Prabhakar, N R; Kou, Y R; Kumar, G K

    1995-01-01

    G proteins are signal coupling molecules that play major roles in mediating the effects of transmitters as well as certain sensory signals. In the present study we examined whether oxygen chemoreception in the carotid body is coupled to G proteins. Experiments were performed on carotid bodies isolated from anesthetized cats. Presence of G proteins was examined with ADP-ribosylation of the carotid body membranes. Pertussis toxin (PTX), which inactivates G proteins in neuronal tissues, ADP-ribosylated a single band of carotid body protein with a molecular mass of 41 kDa. With cholera toxin (CTX) only a faint band of protein corresponding to approximately 45 kDa was evident. Perfusing the isolated carotid bodies with PTX (2.5 micrograms/min; 60 min) attenuated the sensory response to hypoxia by 52% of the controls. Perfusion with CTX (50 micrograms/min; for 60 min), on the other hand, increased baseline activity and potentiated the hypoxic response by 125% of controls. Heat-inactivated toxins, however, had no influence on the carotid body sensory response to hypoxia. These results suggest that G proteins are present in the chemoreceptor tissue and they seem to be coupled to the transduction and/or to the transmission of the hypoxic stimulus.

  15. Acetate enhances the chemosensory response to hypoxia in the cat carotid body in vitro in the absence of CO2-HCO3-.

    PubMed

    Iturriaga, R

    1996-01-01

    To determine if intracellular acidosis enhances hypoxic chemoreception in the absence of CO2-HCO3- at pH 7.4, the effects of sodium acetate (30 mM) were studied on the chemosensory responses of the cat carotid body to hypoxic, stagnant and cytotoxic hypoxia. Carotid bodies were perfused and superfused in vitro with Tyrode's solution, free of CO2-HCO3-, buffered with HEPES-NaOH, pH 7.40, at 36.5 +/d- 0.5 degrees C and equilibrated at PO2 of 125 Torr (perfusate) and < 20 Torr (superfusate). In the absence of acetate, hypoxia (PO2 25 Torr), flow interruption and NaCN (0.01-100 micrograms) augmented the chemosensory discharges. However, in the presence of acetate, the half-excitation time of these responses decreased and their amplitude increased. Thus, acetate enhances the chemosensory response to hypoxic, stagnant and cytotoxic hypoxia. It is suggested that that intracellular acidosis induced by acetate contributes to this potentiation by correcting the alkaline pHi caused by the absence of HCO3-(-)HCO2 in the perfusate.

  16. Reciprocal photolabile O2 consumption and chemoreceptor excitation by carbon monoxide in the cat carotid body: evidence for cytochrome a3 as the primary O2 sensor.

    PubMed

    Lahiri, S; Buerk, D G; Chugh, D; Osanai, S; Mokashi, A

    1995-07-03

    High carbon monoxide (CO) gas tensions (> 500 Torr) at normoxic PO2 (125-140 Torr) stimulates carotid chemosensory discharge in the perfused carotid body (CB) in the absence but not in the presence of light. According to a metabolic hypothesis of O2 chemoreception, the increased chemosensory discharge should correspond to a photoreversible decrease of O2 consumption, unlike a non-respiratory hypothesis. We tested the respiratory vs. non-respiratory hypotheses of O2 chemoreception in the cat CB by measuring the effect of high CO. Experiments were conducted using CBs perfused and superfused in vitro with high CO in normoxic, normocapnic cell-free CO2-HCO3- buffer solution at 37 degrees C. Simultaneous measurements of the rate of O2 disappearance with recessed PO2 microelectrodes and chemosensory discharge were made after flow interruption with and without CO in the perfusate. The control O2 disappearance rate without CO was -3.66 +/- 0.43 (S.E.) Torr/s (100 measurements in 12 cat CBs). In the dark, high CO reduced the O2 disappearance rate to -2.35 +/- 0.33 Torr/s, or 64.2 +/- 9.0% of control (P < 0.005, 34 measurements). High CO was excitatory in the dark, with an increase in baseline neural discharge from 129.2 +/- 47.0 to 399.3 +/- 49.1 impulses per s (P < 0.0001), and maximum discharge rate of 659 +/- 76 impulses/s (N.S. compared to control) during flow interruption. During perfusion with high CO in the light, there were no significant differences in baseline neural discharge or in the maximum neural discharge after flow interruption, and little effect on O2 metabolism (88.8 +/- 11.5% of control, N.S., 29 measurements).(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Carbon monoxide: a role in carotid body chemoreception.

    PubMed

    Prabhakar, N R; Dinerman, J L; Agani, F H; Snyder, S H

    1995-03-14

    Carbon monoxide (CO), produced endogenously by heme oxygenase, has been implicated as a neuronal messenger. Carotid bodies are sensory organs that regulate ventilation by responding to alterations of blood oxygen, CO2, and pH. Changes in blood gases are sensed by glomus cells in the carotid body that synapse on afferent terminals of the carotid sinus nerve that projects to respiratory-related neurons in the brainstem. Using immunocytochemistry, we demonstrate that heme oxygenase 2 is localized to glomus cells in the cat and rat carotid bodies. Physiological studies show that zinc protoporphyrin IX, a potent heme oxygenase inhibitor, markedly increases carotid body sensory activity, while copper protoporphyrin IX, which does not inhibit the enzyme, is inactive. Exogenous CO reverses the stimulatory effects of zinc protoporphyrin IX. These results suggest that glomus cells are capable of synthesizing CO and endogenous CO appears to be a physiologic regulator of carotid body sensory activity.

  18. Carotid and Vagal Body Paragangliomas

    PubMed Central

    del Guercio, Luca; Narese, Donatella; Ferrara, Doriana; Butrico, Lucia; Padricelli, Andrea; Porcellini, Massimo

    Between 1972 and 2012, 25 patients presenting 32 paragangliomas of the neck were observed. Tumor locations included the carotid body (CBTs) in 21 patients and the vagus nerve in 4. Four patients had bilateral CBT and one a bilateral vagal tumor; a metachronous bilateral jugulare paraganglioma was diagnosed in one patient with bilateral CBT Shamblin type III. Five patients presented CBTs type II and three type III. Preoperative embolization was performed in 5 CBTs, with no significant difference in blood loss. Twenty-nine paragangliomas were resected (with three internal carotid artery resection): there were no cerebrovascular accident or perioperative death. Nine patients (36%) had cranial nerve palsy prior to surgery and a postoperative nerve dysfunction occurred in four other tumors (16%). Persistent nerve deficits occurred in 3 patients (12%). No evidence of malignancy was shown, intraoperatively or during a postoperative follow-up period (9 months to 18 years; mean: 8 years). PMID:24251239

  19. Carotid body disease and the physician--chronic carotid glomitis.

    PubMed Central

    Heath, D.; Khan, Q.; Nash, J.; Smith, P.

    1989-01-01

    There are three types of histological change in the carotid bodies which appear to have physiological and clinical associations. A prominence of the dark variant of chief cells with their contents of met-enkephalin and other peptides appears to be associated with acute exposure to hypoxia. Proliferation of sustentacular cells around the clusters of chief cells appears to be related to ageing and also to systemic hypertension. Recently we have described a new condition of chronic carotid glomitis which is characterized by follicles of lymphocytes and may have a basis in auto-immunity. In the present review we report for the first time plasma cell activity in the carotid bodies of an elderly man, especially around nerve fibrils and unmyelinated axons ensheathed in sustentacular cells. Such appearances are consistent with the view that ageing nerve fibrils may be the antigenic stimulus for the development of chronic carotid glomitis. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:2692011

  20. Myocardial hypertrophy induces carotid body hyperplasia.

    PubMed

    Sivridis, Efthimios; Pavlidis, Pavlos; Fiska, Aliki; Pitsiava, Dimitra; Giatromanolaki, Alexandra

    2011-01-01

    The carotid bodies tend to enlarge after long-standing cardiopulmonary disease. Our objective was to investigate whether cardiac hypertrophy is associated with carotid body hyperplasia. Fifteen autopsy cases with combined left and right ventricular hypertrophy were examined and compared with two control groups (16 cases). The study involved a meticulous dissection of carotid bifurcations, thin serial sections, and morphometric analysis of carotid body volume and cell types (progenitor, dark, light, and sustentacular). There was a significant increase in sustentacular cells in all individuals with cardiac hypertrophy, which was not drug-induced, and accompanied by a similar increase in carotid body volume. Dark or light cell accumulation was detected focally and only in three instances. It appears that the generalized sustentacular cell hyperplasia is the result of long-standing hypoxia, while a superimposed focal prominence of dark or light cells may be proliferative or metaplastic in nature and attributed to short-term hypoxia.

  1. Selective activation of carotid nerve fibers by acetylcholine applied to the cat petrosal ganglion in vitro.

    PubMed

    Alcayaga, J; Iturriaga, R; Varas, R; Arroyo, J; Zapata, P

    1998-03-09

    The petrosal ganglion innervates carotid body chemoreceptors through the carotid (sinus) nerve. These primary sensory neurons are activated by transmitters released from receptor (glomus) cells, acetylcholine (ACh) having been proposed as one of the transmitters involved in this process. Since the perikarya of primary sensory neurons share several properties with peripheral sensory endings, we studied the electrical responses of the carotid nerve and glossopharyngeal branch to ACh locally applied to the cat petrosal ganglion superfused in vitro. Ganglionar applications of AChCl (1 microg-1 mg) generated bursts of action potentials conducted along the carotid nerve, while only a few spikes were exceptionally recorded from the glossopharyngeal branch in response to the largest doses. Carotid nerve responses to ACh were dose-dependent, the higher doses inducing transient desensitization. Application of nicotine to the petrosal ganglion also evoked dose-dependent excitatory responses in the carotid nerve. Responses to ACh were reversibly antagonized by adding hexamethonium to the superfusate, more intense and prolonged block of ACh responses being produced by mecamylamine. Ganglionar applications of gamma-amino butyric acid and serotonin, in doses of up to 5 mg, did not induce firing of action potentials in any of the branches of the glossopharyngeal nerve. Our results indicate that petrosal ganglion neurons projecting through the carotid nerve are selectively activated by ACh acting on nicotinic ACh receptors located in the somata of these neurons. Thus, cholinosensitivity would be shared by the membranes of peripheral endings and perikarya of primary sensory neurons involved in arterial chemoreception.

  2. Hyperbaric oxygenation alters carotid body ultrastructure and function.

    PubMed

    Torbati, D; Sherpa, A K; Lahiri, S; Mokashi, A; Albertine, K H; DiGiulio, C

    1993-05-01

    We previously demonstrated that chronic normobaric hyperoxia (NH) for 60-67 h attenuated the carotid chemosensory response to hypoxia, probably initiated by the generation of reactive oxygen species (ROS). Since biological systems are affected by oxygen in a dose-dependent manner, we hypothesized that hyperbaric oxygenation (HBO) would affect the cellular mechanisms of oxygen chemoreception in a shorter time. To test the hypothesis, we studied the effects of oxygen at 5 atmospheres absolute (ATA) on cats (n = 7) carotid body ultrastructure and chemosensory responses to hypoxia, hypercapnia, and to bolus injections of cyanide, nicotine and dopamine. Four control cats breathed room air at 1 ATA. At the termination of the experiments, carotid bodies from 4 cats in each group were fixed and prepared for electron microscopy and morphometry. On the average, HBO diminished the chemosensory responsiveness to hypoxia (P < 0.01, unpaired t-test) within about 2 h, supporting the hypothesis. The responses to hypercapnia or bolus injections of cyanide, nicotine and dopamine were normal. HBO did not diminish the distribution of the dense-cored vesicles but significantly increased the mean volume-density of mitochondria and decreased the cristated area per mitochondrion in the glomus cells. The latter suggests a link between oxidative metabolism and chemosensing, and the former excludes availability of neurotransmitters being the cause of the blunted chemosensory response to hypoxia.

  3. Anatomical variations in human carotid bodies.

    PubMed Central

    Khan, Q; Heath, D; Smith, P

    1988-01-01

    The variations in anatomical structure and position of both carotid bodies were noted in 100 consecutive subjects who came to necropsy. Considerable variations in form were found. Although most carotid bodies (83% on the right and 86% on the left) were of the classic ovoid type, an appreciable minority was bilobed (9% on the right and 7% on the left) or double (7% on the right and 6% on the left); 1% were leaf shaped. All these anatomical variants have to be distinguished from the pathologically enlarged carotid body that may have a smooth or finely nodular surface. Anatomical variants (such as the bilobed) may themselves enlarge as a consequence of carotid body hyperplasia. Images Fig 1 Fig 2 Fig 3 Fig 4 Fig 5 Fig 6 Fig 7 Fig 8 PMID:3209707

  4. Analysis of carotid chemoreceptor responses to substance P analogue in anaesthetized cats.

    PubMed

    Prabhakar, N R; Gouda, E; Kumar, G K; Kou, Y R

    1995-03-18

    Analogues of Substance P (SP) have been shown to act as SP receptor antagonists in various physiological systems. We have previously shown that the carotid body sensory response to hypoxia could be attenuated by D-Pro2-D-Trp7,9-SP (DPDT-SP) and suggested that SP may be important for chemoreception. In the absence of detailed characterization of the antagonistic effects of DPDT-SP, the role of SP in carotid body chemoreception remains uncertain. The present study was undertaken to analyze the effects of DPDT-SP on carotid body activity in anaesthetized cats (n = 18). Intra-carotid infusion of DPDT-SP antagonized SP-induced chemoreceptor stimulation. 90% blockade of SP responses was obtained at infusion rates of 15 micrograms/kg per min of DPDT-SP for 15 min. By contrast, infusions of either saline (controls) or at doses below 10 micrograms/kg per min had no effect on SP responses. The doses that effectively antagonized SP excitation (i.e., 15 micrograms/kg per min) also blocked or markedly attenuated the chemoreceptor responses to hypoxia, without affecting the carotid body stimulation caused by nicotine. The effects of DPDT-SP were associated with significant reduction in baseline activity in normoxia. The antagonistic effects were reversible after terminating the infusion of DPDT-SP. Increasing the dose to 25 micrograms/kg per min, however, abolished the carotid body excitation by any of the stimuli tested (i.e., SP, hypoxia and nicotine), indicating that at higher doses DPDT-SP is non-selective. These results demonstrate that DPDT-SP given in adequate doses to block SP response also attenuates or abolishes the carotid body excitation by hypoxia.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Dopamine modulates carotid nerve responses induced by acetylcholine on the cat petrosal ganglion in vitro.

    PubMed

    Alcayaga, J; Varas, R; Arroyo, J; Iturriaga, R; Zapata, P

    1999-06-12

    We have recently reported that application of acetylcholine (ACh) or nicotine to the petrosal ganglion-the sensory ganglion of the glossopharyngeal nerve-elicits a burst of discharges in the carotid nerve branch, innervating the carotid body and sinus, but not in the glossopharyngeal branch, innervating the tongue and pharynx. Thus, the perikarya of sensory neurons for the carotid bifurcation exhibit selective cholinosensitivity. Since dopamine (DA) modulates carotid nerve chemosensory activity, we searched for the presence of DA sensitivity at the perikarya of these neurons in the cat petrosal ganglion superfused in vitro. Applications of DA in doses of up to 5 mg to the ganglion did not modify the rate of spontaneous discharges in the carotid nerve. However, if DA was applied 30 s before ACh injections, ACh-evoked reactions were modified: low doses of DA enhanced the subsequent responses to ACh, while high doses of DA depressed the responses to ACh. This depressant effect of DA on ACh responses was partially antagonized by adding spiroperone to the superfusate. Our results show that the response to ACh of petrosal ganglion neurons projecting through the carotid nerve is modulated by DA acting on D(2) receptors located in the somata of these neurons. Thus, dopaminergic modulation of cholinosensitivity could be shared also by the membranes of peripheral endings and perikarya of primary sensory neurons involved in arterial chemoreception.

  6. Neurotransmission in the carotid body: transmitters and modulators between glomus cells and petrosal ganglion nerve terminals.

    PubMed

    Iturriaga, Rodrigo; Alcayaga, Julio

    2004-12-01

    The carotid body (CB) is the main arterial chemoreceptor. The most accepted model of arterial chemoreception postulates that carotid body glomus (type I) cells are the primary receptors, which are synaptically connected to the nerve terminals of petrosal ganglion (PG) neurons. In response to natural stimuli, glomus cells are expected to release one (or more) transmitter(s) which, acting on the peripheral nerve terminals of processes from chemosensory petrosal neurons, increases the sensory discharge. Among several molecules present in glomus cells, acetylcholine and adenosine nucleotides and dopamine are considered as excitatory transmitter candidates. In this review, we will examine recent evidence supporting the notion that acetylcholine and adenosine 5'-triphosphate are the main excitatory transmitters in the cat and rat carotid bodies. On the other hand, dopamine may act as a modulator of the chemoreception process in the cat, but as an excitatory transmitter in the rabbit carotid body.

  7. Neurovascular complications following carotid body paraganglioma resection.

    PubMed

    Lamblin, E; Atallah, I; Reyt, E; Schmerber, S; Magne, J-L; Righini, C A

    2016-11-01

    The present consecutive case series reports our experience in the management of carotid body paraganglioma and aims to assess whether the Shamblin classification or tumor size are predictive of early and late postoperative neurovascular complications. A retrospective study included 54 carotid body tumor resections in 49 patients, between 1980 and 2011. Data comprised early (<1month) and late (18 months) postoperative neurovascular complications. Early postoperative complications occurred in 31 cases, including 30 cases of cranial nerve deficit (56%). Cranial nerve deficit occurred in 83% of Shamblin III carotid body paragangliomas and was associated with significantly larger mean tumor size (4±1.4cm versus 2.9±1.3cm; P<0.01). Shamblin III tumor and tumor size>3.2cm emerged as predictive factors for early postoperative peripheral neurological complications. Eight patients (17%) showed no cranial nerve deficit recovery, even after 18 months' follow-up; no predictive factors could be identified for this. Surgical resection remains the only curative treatment in carotid body paraganglioma, with low vascular morbidity. However, early postoperative nerve deficit remains frequent (56%), although mostly temporary, with 17% definitive sequelae at 18 months. Tumor size and Shamblin classification are predictive of early neurovascular complications. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  8. Protein kinase C--a potential modifier of carotid body function.

    PubMed

    Faff, L; Kowalewski, C; Pokorski, M

    1999-04-01

    This article deals with the potential role of protein kinase C (PKC) in signal transduction in the carotid body. The carotid body is a chemosensory organ which, by sensing reductions in arterial blood oxygen tension, is primarily responsible for the hyperventilation of hypoxia. The mechanisms of transduction of the hypoxic stimulus into a neural signal regulating respiration are not clear. Hypoxia increases the phosphoinositide-specific phospholipase C (PLC) activity in the carotid body. The PLC-derived signalling molecules are known to activate PKC. The enzyme might, thus, have the potential to interact with the process of chemoreception. This article demonstrates that PKC is present in the chemoreceptor cells of the cat carotid body and discusses the biology of the enzyme relevant to chemosensory function. This gives rise to the hypothesis that PKC-mediated mechanisms alter chemoreceptor cell function to a sufficient extent to metamorphose the hypoxic signal into an increased discharge frequency in the apposed sinus nerve endings.

  9. Amiloride and carotid body chemoreception of hypercapnia and hypoxia.

    PubMed

    Fitzgerald, R S; Shirahata, M; Lahiri, S

    1990-09-01

    The sodium-proton (Na(+)-H+) antiporter has been found in virtually every tissue where its presence has been investigated. Its principal physiological role is to regulate intracellular pH (pHi). Amiloride (10(-3)-10(-4) M) is a known blocker of the antiporter when Na is present in normal physiological concentrations (130-140 x 10(-3) M). In order to determine if the Na(+)-H+ antiporter participated in the chemoreception of hypercapnia or hypoxia anesthetized, paralyzed, artificially ventilated cats were fitted with a loop in the right common carotid artery for the selective perfusion of the carotid body. Neural activity (imp/10 sec) was recorded from single or few fiber preparations during hypercapnia (PaCO2 = 48-64 Torr) while the carotid body was perfused with Krebs-Ringer bicarbonate solution for 2.5 min, then with its own hypercapnic arterial blood (4 min), then with Krebs-Ringer bicarbonate solution containing 0.6-0.8 x 10(-3) M amiloride (2.5 min), then with its own hypercapnic blood (4 min). After 20 min of rest the protocol was repeated during hypoxia (PaO2 = 35-45 Torr). The carotid body response to hypercapnic blood was unaffected by a preceding perfusion of the amiloride-containing solution but the response to hypoxic blood was decreased by 25% by the amiloride-containing solution. The data suggest the possibility of different mechanisms being involved in the chemoreception of hypercapnia and hypoxia.

  10. Carotid body tumours. A 20-year single-institution experience.

    PubMed

    Dalainas, Ilias; Nano, Giovanni; Casana, Renato; Bianchi, Paolo; Stegher, Silvia; Malacrida, Giovanni; Tealdi, Domenico Giuseppe

    2006-01-01

    The aim of this single-institution retrospective study was to review the surgical outcomes of resection of carotid body tumours over the last 20 years in our hospital. From January 1985 to December 2004, 17 patients were admitted to our institution with carotid body tumours. All patients were treated by surgical resection of the tumour. No perioperative deaths occurred. Perioperative comorbidities were more frequent in patients with large carotid body tumours intimately associated with the carotid vessels. Surgical excision of carotid body tumours is safe and effective even in the long term.

  11. Two cytochrome oxygen consumption model and mechanism for carotid body chemoreception.

    PubMed

    Nair, P K; Buerk, D G; Whalen, W J; Schubert, R W

    1986-01-01

    We have measured sinus nerve discharge, tissue PO2 and oxygen consumption (VO2) in cat carotid bodies under different experimental conditions using our recessed oxygen microelectrode. Our results indicate that the change in chemoreceptor activity with oxygen disappearance following blood flow occlusion can be related to a two cytochrome model for oxygen consumption as previously proposed by Mills and Jöbsis (1972).

  12. Differential effects of oligomycin on carotid chemoreceptor responses to O2 and CO2 in the cat.

    PubMed

    Shirahata, M; Andronikou, S; Lahiri, S

    1987-11-01

    Effects of oligomycin on carotid chemoreceptor responses to O2 and CO2 were investigated using an in situ perfusion technique. Cats were anesthetized, paralyzed, and artificially ventilated. To avoid a possible reaction between an oligomycin-ethanol mixture and blood, we administered oligomycin to the carotid body via cell- and protein-free perfusate. Except for the perfusion periods, the carotid body received its own natural blood supply. Responses to O2, CO2, sodium cyanide, and nicotine of the same carotid chemoreceptor afferents were studied before and after each perfusion. An appropriate low dose of oligomycin completely blocked carotid chemoreceptor response to O2 while preserving the CO2 response. At the same time cyanide response was attenuated leaving nicotine response intact. Additional doses of oligomycin attenuated carotid chemoreceptor response to CO2 as well. Perfusion with a blank solution containing ethanol did not change the carotid body chemoreceptor responses. These effects of oligomycin on carotid chemoreceptor responses to O2 and CO2 were reversible, and restoration of the response to CO2 preceded that to O2. In addition, oligomycin administered into the blood with close intra-arterial injection produced similar differential blockade of O2 and CO2 chemoreception, preserving the nicotine and dopamine effects. This study confirmed the previous findings and provided new evidence showing that 1) the responses of carotid chemoreceptor to O2 and CO2 were separable by oligomycin due to the inhibition of oxidative phosphorylation and 2) the responses to nicotine and dopamine were intact even after blockade of O2 response.

  13. Carotid body O2 chemoreception and mitochondrial oxidative phosphorylation.

    PubMed

    Mulligan, E; Lahiri, S; Storey, B T

    1981-08-01

    The effect on carotid chemoreceptor afferents of oligomycin, an inhibitor of mitochondrial oxidative phosphorylation that does not affect energy conservation, was studied in 20 cats that were anesthetized, paralyzed, and artificially ventilated. Responses of single or a few chemoreceptor afferents to changes in arterial O2 tension (PaO2) at constant arterial CO2 tension were recorded. In addition, responses to nicotine, cyanide, and antimycin A or carbonyl cyanide p-tri-fluoromethoxyphenylhydrazone (FCCP) were tested in normoxia. Oligomycin (50-500 microgram) was administered by close intra-arterial injection, and the same tests were repeated at timed intervals. Initially, oligomycin caused vigorous stimulation of carotid chemoreceptor activity. Subsequently, although the afferent fibers were still active and could be vigorously stimulated by nicotine, they no longer responded to changes in PaO2 or to doses of cyanide, antimycin A, or FCCP. These results separate stimulation of chemoreceptor afferents by hypoxia and metabolic inhibitors and uncouplers from that by nicotine and suggest that intact oxidative phosphorylation, required for maintenance of the intracellular high-energy phosphate levels, forms the basis of O2 chemoreception in the carotid body.

  14. Effect of acute and chronic cobalt administration on carotid body chemoreceptors responses.

    PubMed

    Morelli, L; Di Giulio, C; Iezzi, M; Data, P G

    1994-06-30

    Chronic cobalt exposure leads to release and production of erythropoietin and consequently to polycythemia. Accordingly, cellular elements sensitive to oxygen in the carotid body, would manifest responses during acute and chronic cobalt administration. The carotid body, detects gas changes (PO2, PCO2/pH) in the arterial blood and regulates ventilation and circulation by the afferent nerve discharge. We hypothesized that cobalt interacts with an oxygen sensitive mechanism in the carotid chemoreception and in erythropoietin producing cells. Twelve cats were anesthetized, paralysed and artificially ventilated; few fiber preparation of carotid sinus nerve were recorded during close intraarterial injection of cobalt. In another protocol, 12 rats received an intraperitoneal dose of CoCl2 (10 mg/kg) daily for 6 weeks. At the end, the carotid body was fixed in situ by superfusion. Ultrastructural and morphometric studies were made. Acute administration (0.08-2.3 mumol) promptly stimulated the chemoreceptor afferents. Type I cells increased significantly along with erythropoiesis in the chronic cobalt treated rats. The stimulatory effects of cobalt on the carotid body chemoreceptor showed that sensitive mechanisms in the kidney and in the carotid body are similar, and cobalt interacts with the physiological responses of oxygen.

  15. CO interact with intracellular [H+] with and without CO2-HCO3- in the cat carotid chemosensory discharge.

    PubMed

    Osanai, S; Rozanov, C; Mokashi, A; Buerk, D G; Lahiri, S

    1997-08-01

    To test the hypothesis whether CO2-HCO3- buffer is essential for the expression of chemoreception and to distinguish between pHi and pHo interaction with pCO in the carotid chemosensory response, we superfused-perfused in vitro cat carotid bodies using HEPES-Tyrode's solution with and without CO2-HCO3-, and compared the responses at the same pHo in the absence and presence of light. In the absence of light, pCO (> 138 Torr) stimulated the carotid body chemoreceptors in CO2-HCO3- buffer at pHo of 7.40, whereas pCO (69-550 Torr) did not stimulate the neural discharge in HEPES buffer at the pHo of 7.4-7.1 but did so below pHo 7.1. In the presence of light, all the responses were diminished proportionately.

  16. Preoperative imaging diagnosis of carotid body tumors.

    PubMed

    Pacheco-Ojeda, Luis A; Martínez-Viteri, Miguel A

    2010-01-01

    Carotid body tumors (CBTs) are relatively frequent lesions encountered at high altitudes, such in as the Andean Mountains. A correct preoperative diagnosis is essential for surgical planning and performance. For this reason, we have reviewed the evolution of our experience in the imaging diagnosis of these tumors. Between 1980 and June 2008, 160 CBTs were diagnosed. A total of 138 tumors were operated on, 4 are waiting for surgery, and 18 were not operated on because of age, medical conditions, or patient refusal. We have reviewed retrospectively the modalities of imaging diagnosis in our patients who underwent operation. Among the 138 tumors operated on, a correct preoperative diagnosis was done in 127 cases (92%). The preoperative diagnosis of the remaining 11 patients was unspecified benign tumor for 6 patients and neck lymph node for 5 patients. The imaging methods performed by different radiologists were conventional ultrasound, color Doppler ultrasound, carotid conventional angiography (CA), axial tomography, magnetic resonance and magnetic resonance angiography, and computed tomographic angiography (CTA). Most patients had more than one image study. Review of radiologist reports revealed a correct diagnosis in all carotid CA, magnetic resonance studies, and CTA. Additionally, CTA appeared to be a valuable method to predict the Shamblin group. Clinical suspicion and current image techniques permit a correct diagnosis in practically all cases of CBT.

  17. Stimulus interaction between CO2 and almitrine in the cat carotid chemoreceptors.

    PubMed

    Lahiri, S; Mokashi, A; Huang, W; Sherpa, A K; Di Giulio, C

    1989-07-01

    The hypothesis that augmentation of the carotid chemoreceptor response to hypoxia by almitrine is due in part to an increased response to CO2 was tested by using single or few fiber preparation of carotid body chemosensory fibers in 12 cats anesthetized with alpha-chloralose. To differentiate between the plausible mechanisms of effects, we also tested the responsiveness of the afferents to cyanide and nicotine before and after almitrine. After a saturation dose of almitrine (1 mg.kg-1 followed by 0.5 mg.kg-1.h-1) the chemosensory responses to CO2 strikingly increased even during hyperoxia: the afferents showing an increased transient peak activity at the onset of hypercapnia, an augmented steady-state response to CO2 stimulus, and a decreased arterial PCO2 stimulus threshold. Thus, the effect of almitrine on carotid chemoreceptor response to hypoxia could be explained, at least in part, by its multiplicative stimulus interaction with CO2. After almitrine, the chemoreceptor response to cyanide, which is dependent on arterial PO2, was not particularly augmented relative to those of nicotine. Accordingly, the O2-sensing mechanism does not appear to be the primary site of almitrine effect. The results also indicate that the site of CO2 chemoreception resides downstream from those of hypoxia.

  18. Role of. alpha. sub 2 -adrenergic receptors in the carotid body response to hypoxia

    SciTech Connect

    Kou, Y.R.; Ernsberger, P.; Cherniack, N.S.; Prabhakar, N.R. )

    1990-02-26

    Clonidine, which acts in part as an {alpha}{sub 2}-adrenergic receptor agonist, depresses ventilation. The authors examined the role of {alpha}{sub 2}-receptors in carotid chemoreceptor activity. The density of {alpha}{sub 2}-receptors was determined in membrane fractions of 18 cat carotid bodies using {sup 125}I-iodoclonidine with 0.1 mM epinephrine or 10 {mu}M SKF-86466 defining nonspecific binding. {alpha}{sub 2}-Adrenergic receptor density averaged 0.6{plus minus}0.1 fmol/carotid body (mean {plus minus} SEM) and was comparable to other sympathetic target tissues. The authors then studied the effects of an agonist (guanabenz) and an antagonist (SKF-86466; 6-Cl-N-methyl-2,3,4,5-tetrahydro-1-H3-benzazepine) specific for {alpha}{sub 2}-receptors on baseline and hypoxia-stimulated carotid body discharge, in 10 anesthetized, paralyzed and artificially ventilated cats. Intracarotid infusion of guanabenz for 5 minutes caused a dose-dependent depression of the baseline activity and reduced the chemoreceptor response to hypoxia by 88.0{plus minus}5.8% of the vehicle-injected controls. Intravenous administration of SKF-86466 reversed the effects of guanabenz on the carotid body activity. in contrast, chemoreceptor depression caused by dopamine was unaffected by SKF-86466. SKF-86466 alone increased baseline discharge and potentiated the chemoreceptor response to hypoxia by 34.0 {plus minus} 9.6% of the controls. These results demonstrate that {alpha}{sub 2}-adrenergic receptors are present in the cat carotid body and they exert an inhibitory influence on the chemoreceptor response to hypoxia.

  19. Pathogenic Roles of the Carotid Body Inflammation in Sleep Apnea

    PubMed Central

    2014-01-01

    Breathing difficulties in sleep are a hallmark of sleep-disordered breathing commonly observed in patients with sleep disorders. The pathophysiology of sleep apnea is in part due to an augmented activity of the carotid body chemoreflex. Arterial chemoreceptors in the carotid body are sensitive to inflammatory cytokines and immunogenic molecules in the circulation, because cytokine receptors are expressed in the carotid body in experimental animals and human. Intriguingly, proinflammatory cytokines are also locally produced and released in the carotid body. Also, there are significant increases in the expression of proinflammatory cytokines, cytokine receptors, and inflammatory mediators in the carotid body under hypoxic conditions, suggesting an inflammatory response of the carotid body. These upregulated cytokine signaling pathways could enhance the carotid chemoreceptor activity, leading to an overactivity of the chemoreflex adversely effecting breathing instability and autonomic imbalance. This review aims to summarize findings of the literature relevant to inflammation in the carotid body, with highlights on the pathophysiological impact in sleep apnea. It is concluded that local inflammation in the carotid body plays a pathogenic role in sleep apnea, which could potentially be a therapeutic target for the treatment of the pathophysiological consequence of sleep apnea. PMID:25276055

  20. Interaction of dopamine and haloperidol with O2 and CO2 chemoreception in carotid body.

    PubMed

    Lahiri, S; Nishino, T; Mokashi, A; Mulligan, E

    1980-07-01

    Effects of dopamine and of a dopaminergic blocker, haloperidol, on the responses of carotid body chemoreceptors to hypoxia and hypercapnia were investigated in 16 anesthetized cats. Intravenous infusion of dopamine (10-20 micrograms.min-1) decreased carotid body chemoreceptor responses to hypoxia and hypercapnia. The effect was greater at higher levels of arterial oxygen and carbon dioxide tension (PaO2 and PaCO2) stimulus. Thus, the magnitude of the dopamine effect depended on the degree of both PO2- and PCO2-mediated excitation of the receptors. Haloperidol potentiated responses to both hypoxia and hypercapnia but apparently did not stimulate the receptors in the absence of these stimuli. Potentiation by haloperidol and inhibition by dopamine of excitatory effects due to PaO2 decrease and PaCO2 increase are complementary. The data suggest that chemoreception of dopamine, O2, and CO2 converge at some site in the carotid body. Persistence of hypoxic and hypercapnic responses, following dopamine-blocking doses of haloperidol, does not support the theory that regulation of dopamine release is responsible for O2 and CO2 chemoreception in carotid body of the cat.

  1. Patch clamp study of mouse glomus cells using a whole carotid body.

    PubMed

    Yamaguchi, Shigeki; Lande, Boris; Kitajima, Toshimitsu; Hori, Yuichi; Shirahata, Machiko

    2004-03-04

    Some electrophysiological characteristics of mouse glomus cells (DBA/2J strain) were investigated using an undissociated carotid body. The carotid body with major carotid arteries was placed in a recording chamber, and glomus cells were visualized with a water immersion lens combined with an infrared differential interference video camera. Patch clamp experiments revealed that voltage-gated outward current, but not inward current, was easily observed in glomus cells. Pharmacological experiments and the kinetics of the current suggest that outward current is via delayed rectifier, A type, and large conductance calcium-activated K channels. Furthermore, K current was reversibly attenuated by mild hypoxia. The results suggest electrophysiological similarities of glomus cells among the cat, the rat, and the DBA/2J mouse. The method appears useful for physiological experiments.

  2. Peripheral Chemoreceptors: Function and Plasticity of the Carotid Body

    PubMed Central

    Kumar, Prem; Prabhakar, Nanduri R.

    2014-01-01

    The discovery of the sensory nature of the carotid body dates back to the beginning of the 20th century. Following these seminal discoveries, research into carotid body mechanisms moved forward progressively through the 20th century, with many descriptions of the ultrastructure of the organ and stimulus-response measurements at the level of the whole organ. The later part of 20th century witnessed the first descriptions of the cellular responses and electrophysiology of isolated and cultured type I and type II cells, and there now exist a number of testable hypotheses of chemotransduction. The goal of this article is to provide a comprehensive review of current concepts on sensory transduction and transmission of the hypoxic stimulus at the carotid body with an emphasis on integrating cellular mechanisms with the whole organ responses and highlighting the gaps or discrepancies in our knowledge. It is increasingly evident that in addition to hypoxia, the carotid body responds to a wide variety of blood-borne stimuli, including reduced glucose and immune-related cytokines and we therefore also consider the evidence for a polymodal function of the carotid body and its implications. It is clear that the sensory function of the carotid body exhibits considerable plasticity in response to the chronic perturbations in environmental O2 that is associated with many physiological and pathological conditions. The mechanisms and consequences of carotid body plasticity in health and disease are discussed in the final sections of this article. PMID:23728973

  3. Anesthetic approaches in carotid body tumor surgery

    PubMed Central

    Kavakli, Ali Sait; Ozturk, Nilgun Kavrut

    2016-01-01

    OBJECTIVE: Carotid body tumors (CBT) are benign tumors that originate from neural non-chromaffin cells that are typically localized near carotid bifurcation. Surgical removal of the tumor is the most appropriate treatment. General anesthesia is preferred anesthetic technique for CBT surgery. Basic elements of anesthetic management are protection of hemodynamic stability and maintaining cerebral perfusion pressure (CPP). The aim of this study was to evaluate anesthetic management of CBT surgery and present the literature knowledge. METHODS: The study included 10 consecutive patients with diagnosis of CBT who underwent surgery at Antalya Training and Research Hospital, in Antalya, Turkey, between 2013 and 2016. Preoperative demographic details; comorbidities; side of surgical site; duration of operation; length of intensive care unit (ICU) and hospital stay; change of intraoperative blood pressure; use of inotropic drugs, blood products, and analgesics; postoperative visual analogue scale (VAS) pain score; and complications were recorded. RESULTS: According to Shamblin classification, 3 tumors were type I and the remaining 7 were type II. Tumors were located on right side in 6 patients, and on left in 4. Blood loss sufficient to require transfusion was observed in 1 patient. Average intraoperative blood loss was 287±68 mL. Tachycardia and hypertension were observed in 1 patient; bradycardia and hypotension were seen in 4 patients. Infusion for inotropic support was administered to 1 patient. Mean duration of operation was 109±20 minutes. Mean VAS score was 4±1, mean ICU tramadol consumption was 80±25 mg. Duration of stay in ICU and hospital were 2.4±1.1 hours and 3.8±0.7 days, respectively. Mortality and neurological complications were not seen in postoperative period. CONCLUSION: CBT surgery requires close and complex anesthesia management. Protection of hemodynamic stability against sudden hemodynamic changes, monitoring, and maintaining CPP are the most

  4. Selective inhibition of the carotid body sensory response to hypoxia by the substance P receptor antagonist CP-96,345.

    PubMed

    Prabhakar, N R; Cao, H; Lowe, J A; Snider, R M

    1993-11-01

    Carotid bodies are sensory organs for monitoring arterial oxygen and CO2. Previous studies have shown that chemoreceptor tissue contains substance P (SP) and exogenously administered SP augments chemosensory discharge. In the present study, we examined the physiological importance of SP in carotid body chemoreception by using a selective nonpeptide SP [neurokinin (NK) 1] receptor antagonist CP-96,345. In experiments performed on anesthetized cats, sensory discharge was recorded from the carotid body in situ. To control for alterations in blood flow, additional studies were conducted on the carotid body in vitro. In in vivo studies, close carotid body (intraarterial) administration of CP-96,345 attenuated the sensory response to hypoxia in a dose-dependent manner with 73% of the response abolished at doses of 0.3-0.6 mg/kg. Comparable doses of the (2R,3R)-enantiomer had no effect on hypoxia-induced excitation, indicating that the effect of CP-96,345 was not due to nonspecific action. In contrast, the carotid body response to high CO2 was not affected by CP-96,345, implying that only the hypoxic response is mediated by NK-1 receptor and confirming that the effect of the SP antagonist was not due to nonspecific actions. Marked attenuation of the sensory response to hypoxia was also obtained in the carotid body in vitro, suggesting that the effects of the NK-1 antagonist were not secondary to cardiovascular changes. These results demonstrate that CP-96,345 attenuates or abolishes the chemosensory response to hypoxia but not to CO2 and suggest that SP mediates the hypoxia-induced sensory excitation in the cat carotid body via NK-1 receptor activation.

  5. A case of carotid body tumor concomitant with carcinoid tumor.

    PubMed

    Mun, Mi Jin; Lee, Jin Choon; Lee, Byung Joo

    2015-02-01

    Neuroendocrine tumors typically fall into two broad categories: those of epithelial origin and those of neural derivation. The former group includes carcinoid tumors and the latter includes paraganglioma. Although paraganglioma and carcinoid tumor have different biologic behaviors, their overlapping histological appearance can pose diagnostic challenges. Carcinoid tumors are rare, slow-growing neuroendocrine tumors arising from the enterochromaffin cells disseminated throughout the gastrointestinal and bronchopulmonary systems. Carotid body tumor is the most common type of extra-adrenal paraganglioma. Paraganglioma tends to grow slowly but can compress adjacent vessel and nerve. A 63-year-old woman showed huge mass extending from carotid body to skull base, encircling internal and external carotid arteries on magnetic resonance image. Surgical removal of carotid body tumor was done after embolization procedure. Postoperative histopathologic examination and immunohistochemical analysis were consistent with paraganglioma concomitant with carcinoid tumor in carotid body. Primary cervical carcinoid tumor is extremely rare, and to the best of our knowledge, this is the first case of concomitant existence of paraganglioma and carcinoid tumor in carotid body.

  6. Cervical Vertebral Body Chordoma in a Cat.

    PubMed

    Hampel, R; Taylor-Brown, F; Priestnall, S L

    2016-05-01

    A 9-year-old, neutered female Maine Coon cat with a 6-week history of progressive ataxia was diagnosed with a cervical vertebral body mass using magnetic resonance imaging. The mass displaced and compressed the cervical spinal cord. The cat was humanely destroyed and necropsy examination confirmed a mass within the second cervical vertebral body. Microscopically, the mass was composed of large, clear, vacuolated ('physaliferous') cells. Immunohistochemically, the neoplastic cells expressed both cytokeratin and vimentin and the final diagnosis was a cervical, vertebral body chordoma. This is only the third report of a chordoma in this species and the first in this location. Chordoma should be considered as a potential differential diagnosis for tumours arising from the cervical vertebrae in the cat.

  7. Current surgical management of carotid body tumors.

    PubMed

    Davila, Victor J; Chang, James M; Stone, William M; Fowl, Richard J; Bower, Thomas C; Hinni, Michael L; Money, Samuel R

    2016-12-01

    Carotid body tumors (CBTs) are rare. Management guidelines may include genetic testing for succinate dehydrogenase (SDH) mutations. We performed an institutional review of the surgical management of CBT. A retrospective analysis (1994-2015) of CBT excisions at our institution was performed. Data obtained included demographics, genetic testing (if performed), intraoperative details, postoperative morbidity, and long-term outcomes. Data from the first CBT excision were included in patients with bilateral tumors. Genetic testing was routinely offered in patients with a family history of CBT or multiple paragangliomas. A total of 183 CBTs (124 female [67.7%]) were excised. A neck mass was present in 106 patients (57.9%), 24 patients (12.1%) presented with tenderness or neck pain, and 3 (1.6%) presented with cranial nerve dysfunction. Computed tomography (57.9%) or magnetic resonance imaging (51.3%) were the most commonly used imaging modalities. Preoperative angiography was performed in 73 patients (39.8%), and 62 of them (84.5%) underwent embolization or internal carotid balloon occlusion testing, or both. Mean tumor diameter was 3.2 cm (range, 0.6-7.2 cm). There were 71 (38.8%), 75 (41%), and 37 (20.2%) Shamblin type 1, 2, and 3 tumors, respectively. Average operating time was 224 minutes (range, 52-696 minutes). Average blood loss was 143.9 mL (range, 10-2000 mL). Arterial reconstruction with an interposition graft was required in 10, and patch angioplasty was performed in four. Cranial nerve injury was permanent in 10 (5.5%), and the rate of stroke was 1% (n = 2). A total of 382 lymph nodes were excised, and all were benign. There were no deaths ≤30 days. Only one patient presented with malignant disease 2 years after CBT excision, and this patient did not undergo genetic testing. Thirty-four (18.6%) had a family history of CBT. SDH testing was performed in 18 patients, and 17 tested positive. Positive genetic testing had a correlation with earlier age

  8. Effect of osmotic stimuli on the carotid baroreceptor and chemoreceptor discharges in cats.

    PubMed

    Trzebski, A; Chruścielewski, L; Majcherczyk, S

    1978-01-01

    In 15 cats under chloralose-urethan anaesthesia carotid sinus area was arterially isolated and perfused with artificially pulsatile pressures. Solutions of NaCl, of various osmolality, mannitol, glucose and bicarbonate were locally perfused through the isolated carotid area and the single baroreceptor and chemoreceptor fibre activity was recorded with standard technique. An increase in the osmolality of the perfused fluid evoked an increase of the single baroreceptor discharge. Each pulse pressure produced more spikes of higher frequency in big A type baroreceptor fibres. Clear effects were observed during perfusion of 300 mM NCl solutions. Solutions of higher osmolility transformed rhythmical pulse pressure discharge into continuous baroreceptor firing. The excitatory effects of hyperosmolar solutions were reversible after switching to the perfusion fluids of normal osmolality. An increased activity was also observed in the single carotid chemoreceptor fibres. It is concluded that both baro- and chemoreceptors are sensitive to osmotic stimulation.

  9. Evidence for histamine as a new modulator of carotid body chemoreception.

    PubMed

    Rio, R Del; Moya, E A; Alcayaga, J; Iturriaga, R

    2009-01-01

    It has been proposed that histamine is an excitatory transmitter between the glomus cells of the carotid body (CB) and the nerve endings of the petrosal ganglion (PG) neurons. The histamine biosynthetic pathway and the presence of histamine H1, H2 and H3 receptors have been reported in the CB. Thus, histamine meets some of the criteria to be regarded as a transmitter. However, there is no evidence that glomus cells contain histamine, or whether its application produces chemosensory excitation. Therefore, we studied its immunocytochemical localization on cat CB and its effects on chemosensory activity. Using perfused and superfused in vitro CB and PG preparations, we assessed the effects of histamine hydrochloride on chemosensory discharges and of histamine H1, H2 and H3 receptor blockers. We found the presence of histamine immunoreactivity in dense-core vesicles in glomus cells. In an in vitro CB preparation we performed pharmacological experiments to characterize histamine effects. The application of histamine hydrochloride (0.5-1,000 microg) to the CB produces a dose-dependent increase in the carotid sinus nerve activity. The H1 receptor blockade with pyrilamine 500 nM produces partial decrease of the histamine-induced response, whereas the H2 receptor blockade (ranitidine 100microM) fail to abolish the histamine excitatory effects. Antagonism of the H3 receptor results in an increase in carotid body chemosensory activity. On the other hand, application of histamine to the isolated PG had no effect on the carotid nerve discharge. Our results suggest that histamine is a modulator of the carotid body chemoreception through H1 and H3 receptor activation.

  10. Gasotransmitter Regulation of Ion Channels: A Key Step in O2 Sensing By the Carotid Body

    PubMed Central

    Prabhakar, Nanduri R.

    2014-01-01

    Carotid bodies detect hypoxia in arterial blood, translating this stimulus into physiological responses via the CNS. It is long established that ion channels are critical to this process. More recent evidence indicates that gasotransmitters exert powerful influences on O2 sensing by the carotid body. Here, we review current understanding of hypoxia-dependent production of gasotransmitters, how they regulate ion channels in the carotid body, and how this impacts carotid body function. PMID:24382871

  11. Chemical modification of carotid body chemoreception by sulfhydryls.

    PubMed

    Lahiri, S

    1981-05-29

    Sulfhydryl reagents cause striking augmentation of the chemoreceptor responses of the carotid body to hypoxia. This indicates that a cellular plasma membrane protein with a reactive sulfhydryl group is a constituent part of the chemoreceptor architecture and provides a means of identification, localization, and isolation of the protein.

  12. [Carotid body paraganglioma in a teenager. Case report].

    PubMed

    López-Vázquez, María Elisa; Llamas-Macías, Francisco Javier; Nuño-Escobar, César; González-Ojeda, Alejandro; Fuentes-Orozco, Clotilde; Macías-Amezcua, Michel Dassaejv

    2014-01-01

    Paragangliomas of the head and neck are neuroendocrine tumors. They have a low incidence (0.6%), are generally benign, have a poorly defined etiology, and multiple factors have been associated with their origin. Humans and other species living at high altitudes (>2000 m above sea level) are subjected to a relatively chronic hypoxia and there is a high prevalence of the development of carotid body hyperplasia and eventually paragangliomas. This disease is usually seen in patients in their 50s and in their 30s if there is a family history. We present the case of a 16 year-old female with acute pharyngitis and growing tumor located on the left side of the neck, without symptoms. A duplex Doppler ultrasound showed a solid nodular lesion on the left carotid bifurcation. A left lateral cervicotomy was performed, finding a highly vascularized tumor of 4 × 3 × 3 cm involving the common carotid from its middle third, the internal carotid up to the cranial base, and the external carotid to its upper third, and intimately related to the trachea, esophagus and cervical spine. The tumor was completely resected and the histopathological analysis corroborated the presence of paragangliomas. The publication of this case is relevant and of clinical interest due to the uncommon age of presentation and the fact that it should be considered as a diagnostic possibility.

  13. Carotid body denervation prevents fasting hyperglycemia during chronic intermittent hypoxia.

    PubMed

    Shin, Mi-Kyung; Yao, Qiaoling; Jun, Jonathan C; Bevans-Fonti, Shannon; Yoo, Doo-Young; Han, Woobum; Mesarwi, Omar; Richardson, Ria; Fu, Ya-Yuan; Pasricha, Pankaj J; Schwartz, Alan R; Shirahata, Machiko; Polotsky, Vsevolod Y

    2014-10-01

    Obstructive sleep apnea causes chronic intermittent hypoxia (IH) and is associated with impaired glucose metabolism, but mechanisms are unknown. Carotid bodies orchestrate physiological responses to hypoxemia by activating the sympathetic nervous system. Therefore, we hypothesized that carotid body denervation would abolish glucose intolerance and insulin resistance induced by chronic IH. Male C57BL/6J mice underwent carotid sinus nerve dissection (CSND) or sham surgery and then were exposed to IH or intermittent air (IA) for 4 or 6 wk. Hypoxia was administered by decreasing a fraction of inspired oxygen from 20.9% to 6.5% once per minute, during the 12-h light phase (9 a.m.-9 p.m.). As expected, denervated mice exhibited blunted hypoxic ventilatory responses. In sham-operated mice, IH increased fasting blood glucose, baseline hepatic glucose output (HGO), and expression of a rate-liming hepatic enzyme of gluconeogenesis phosphoenolpyruvate carboxykinase (PEPCK), whereas the whole body glucose flux during hyperinsulinemic euglycemic clamp was not changed. IH did not affect glucose tolerance after adjustment for fasting hyperglycemia in the intraperitoneal glucose tolerance test. CSND prevented IH-induced fasting hyperglycemia and increases in baseline HGO and liver PEPCK expression. CSND trended to augment the insulin-stimulated glucose flux and enhanced liver Akt phosphorylation at both hypoxic and normoxic conditions. IH increased serum epinephrine levels and liver sympathetic innervation, and both increases were abolished by CSND. We conclude that chronic IH induces fasting hyperglycemia increasing baseline HGO via the CSN sympathetic output from carotid body chemoreceptors, but does not significantly impair whole body insulin sensitivity. Copyright © 2014 the American Physiological Society.

  14. Protein phosphorylation signaling mechanisms in carotid body chemoreception.

    PubMed

    Wang, Z Z; He, L; Chen, J; Dinger, B; Stensaas, L; Fidone, S

    1999-01-01

    Chemotransduction in the carotid body occurs in specialized type I cells and likely involves a complex series of regulated events which culminates in the release of neurotransmitter agents and the excitation of afferent nerve fibers. Previous studies have shown that multiple factors, including the levels of calcium and cyclic nucleotide second messengers, are important regulators of the chemoreceptor transduction cascade in type I cells. In addition, increases in electrical excitability induced in type I cells by chronic exposure to hypoxia are mimicked by agents which elevate intracellular cyclic AMP levels [Stea et al., J Neurosci 1995;15:2192-2202]. These and other findings suggest that protein kinases, and the phosphorylation of specific protein targets are important components of the hypoxic transduction machinery. Moreover, protein kinase-mediated cascades may participate in the well-known physiological adjustments which occur in the carotid body during prolonged stimulation. In the current study, our data demonstrate (1) the presence of specific protein kinases and target phosphoproteins in the carotid body, and also in the morphologically similar small intensely fluorescent cells of the superior cervical sympathetic ganglia. (2) Nitric oxide production and efferent inhibition in the chemosensory tissue is reduced in the presence of the specific tyrosine kinase inhibitor, lavendustin A. (3) Hypoxia-induced catecholamine release from type I cells is inhibited by the protein kinase A antagonist, Rp-cAMPs. And finally (4), exposure to chronic hypoxia up-regulates the expression of the tyrosine kinase, fyn, and an important growth regulatory phosphoprotein, growth associated protein-43 (GAP-43). These findings suggest that second messenger-mediated phosphorylation and dephosphorylation of specific protein targets is a mechanism capable of regulating diverse cellular functions in the carotid body during acute and chronic stimulation.

  15. The histology of the carotid bodies in highlanders from Ladakh

    NASA Astrophysics Data System (ADS)

    Khan, Q.; Heath, D.; Smith, P.; Norboo, T.

    1988-12-01

    A histological study was made of the carotid bodies in a boy and three adult male highlanders born and residing between altitudes of 3300 m to 4200 m in Ladakh. The carotid bodies were enlarged in two of the men, and in all four subjects showed increased numbers and enlargement of the dark variants of the chief cells of the glomic tissue. In these dark cells the cytoplasm was voluminous, formed streamers and contained many intracytoplasmic vesicles of which some had mused to form larger vesicles that appeared to have discharged from the cell surface. Immunohistochemical studies showed that these cells contained considerable amounts of the peptide met-enkephalin. It is thus considered that prominence of dark cells containing this peptide is characteristic of sustained exposure of the carotid bodies to hypobaric hypoxia. In the middle-aged highlander there was a prominence of sustentacular cells which encroached upon the cores of chief cells and this may be associated with the characteristic loss of hypoxic ventilatory response in the highlander.

  16. Inhibitory effects of NO on carotid body: contribution of neural and endothelial nitric oxide synthase isoforms.

    PubMed

    Valdés, Viviana; Mosqueira, Matías; Rey, Sergio; Del Rio, Rodrigo; Iturriaga, Rodrigo

    2003-01-01

    We tested the hypothesis that nitric oxide (NO) produced within the carotid body is a tonic inhibitor of chemoreception and determined the contribution of neuronal and endothelial nitric oxide synthase (eNOS) isoforms to the inhibitory NO effect. Accordingly, we studied the effect of NO generated from S-nitroso-N-acetylpenicillamide (SNAP) and compared the effects of the nonselective inhibitor N(omega)-nitro-l-arginine methyl ester (l-NAME) and the selective nNOS inhibitor 1-(2-trifluoromethylphenyl)-imidazole (TRIM) on chemosensory dose-response curves induced by nicotine and NaCN and responses to hypoxia (Po(2) approximately 30 Torr). CBs excised from pentobarbitone-anesthetized cats were perfused in vitro with Tyrode at 38 degrees C and pH 7.40, and chemosensory discharges were recorded from the carotid sinus nerve. SNAP (100 microM) reduced the responses to nicotine and NaCN. l-NAME (1 mM) enhanced the responses to nicotine and NaCN by increasing their duration, but TRIM (100 microM) only enhanced the responses to high doses of NaCN. The amplitude of the response to hypoxia was enhanced by l-NAME but not by TRIM. Our results suggest that both isoforms contribute to the NO action, but eNOS being the main source for NO in the cat CB and exerting a tonic effect upon chemoreceptor activity.

  17. The Human Carotid Body Gene Expression and Function in Signaling of Hypoxia and Inflammation.

    PubMed

    Kåhlin, Jessica; Mkrtchian, Souren; Ebberyd, Anette; Eriksson, Lars I; Fagerlund, Malin Jonsson

    2015-01-01

    Although animal carotid body oxygen sensing and signaling has been extensively investigated, the human carotid body remains essentially uncharacterized. Therefore, we aimed to study the human carotid body in terms of morphology, global and specific expression of sensing and signaling genes as well as inflammatory genes. The human carotid body response to brief or prolonged hypoxia was studied in carotid body slices from adult surgical patients and ACh, ATP and cytokine release was analyzed. We demonstrate that the human carotid body expresses key oxygen sensing and signaling genes in similarity with animal carotid bodies with a few diverging data. The human carotid body moreover shows enrichment of genes in the inflammatory response and releases pro and anti-inflammatory cytokines in response to prolonged hypoxia. In response to acute hypoxia the human carotid body releases ACh and ATP and we thus translate previous findings in animal models to human tissue. We conclude that by releasing pro- and anti-inflammatory cytokines during hypoxia the human carotid body displays a structural and functional capacity to participate in sensing and mediating systemic inflammation.

  18. Body condition of feral cats and the effect of neutering.

    PubMed

    Scott, Karen C; Levy, Julie K; Gorman, Shawn P; Newell, Susan M

    2002-01-01

    Considerable debate exists regarding the most appropriate methods for controlling feral cat populations, both from humane and logistical points of view. The physical condition of feral cats has not been reported, and it is not known if these cats benefit from neutering. This study investigates the body condition of feral cats by measuring body weight (BW), body condition score (BCS; Burkholder, 2000; Laflamme, Kealy, & Schmidt, 1994), and falciform fat pad. The study includes lateral abdominal radiographs taken at the time of neutering of 105 adult feral cats for measurement of falciform fat pad depth and area. At that time we also assessed BW and BCS. One year later we assessed the effects of neutering on body condition by evaluating a subsample of 14 cats. At the time of surgery, the cats were lean but not emaciated (BW 3.1 +/- 0.9 kg; BCS 4 +/- 1; based on a 1 to 9 scale ranging from 1 [emaciated] to 9 [grossly obese]). Falciform fat pad depth and area averaged 7.1 mm and 197.4 mm2, respectively, indicating a small amount of fat. Fourteen cats, reevaluated 1 year after neutering, increased 260% + 90% in falciform fat pad depth, 420% +/- 390% in fat pad area, 40% +/- 4% in BW, and 1 level in BCS ranking (1 to 9 scale; all differences p <.001). Similar to confined socialized cats, feral cats gained significant weight and body fat after neutering.

  19. The human carotid body releases acetylcholine, ATP and cytokines during hypoxia.

    PubMed

    Kåhlin, Jessica; Mkrtchian, Souren; Ebberyd, Anette; Hammarstedt-Nordenvall, Lalle; Nordlander, Britt; Yoshitake, Takashi; Kehr, Jan; Prabhakar, Nanduri; Poellinger, Lorenz; Fagerlund, Malin Jonsson; Eriksson, Lars I

    2014-08-01

    Studies on experimental animals established that the carotid bodies are sensory organs for detecting arterial blood O2 levels and that the ensuing chemosensory reflex is a major regulator of cardiorespiratory functions during hypoxia. However, little information is available on the human carotid body responses to hypoxia. The present study was performed on human carotid bodies obtained from surgical patients undergoing elective head and neck cancer surgery. Our results show that exposing carotid body slices to hypoxia for a period as brief as 5 min markedly facilitates the release of ACh and ATP. Furthermore, prolonged hypoxia for 1 h induces an increased release of interleukin (IL)-1β, IL-4, IL-6, IL-8 and IL-10. Immunohistochemical analysis revealed that type 1 cells of the human carotid body express an array of cytokine receptors as well as hypoxia-inducible factor-1α and hypoxia-inducible factor-2α. Taken together, these results demonstrate that ACh and ATP are released from the human carotid body in response to hypoxia, suggesting that these neurotransmitters, as in several experimental animal models, play a role in hypoxic signalling also in the human carotid body. The finding that the human carotid body releases cytokines in response to hypoxia adds to the growing body of information suggesting that the carotid body may play a role in detecting inflammation, providing a link between the immune system and the nervous system.

  20. Heinz body formation associated with ketoacidosis in diabetic cats.

    PubMed

    Christopher, M M; Broussard, J D; Peterson, M E

    1995-01-01

    Oxidative damage plays an important role in the pathophysiology of diabetes and diabetic complications. Feline hemoglobin is uniquely susceptible to oxidative denaturation; therefore, Heinz body formation is a highly sensitive indicator of in vivo oxidative stress in this species. Heinz bodies also contribute to anemia. We investigated hematological and clinical biochemical changes in 30 cats with spontaneous diabetes mellitus (as compared to 15 healthy control cats) and evaluated the relationship of these changes to erythrocyte oxidative damage. Cats were categorized as ketoacidotic or nonketoacidotic based on their clinical presentation and the presence of urine ketones. Ketoacidotic cats had significantly (P = .0009) more Heinz bodies (28.3% +/- 9.1%) than nonketotic diabetic cats (6.5% +/- 1.60%) and healthy control cats (0.6% +/- 0.2%). Percent Heinz bodies in diabetic cats directly correlated with plasma beta-hydroxy-butyrate concentration (r = .622; P = .0002), as well as with serum chloride concentration (r = -0.576; P = 0.0009) and the number of monocytes (r = .536; P = .0023). Percent Heinz bodies were negatively correlated with erythrocyte glutathione concentrations. Erythrocyte membrane lipid peroxidation was slightly but not significantly increased in diabetic cats. There were no significant associations between percent Heinz bodies and degree of anemia, hyperglycemia, or glycohemoglobin. These data indicate that ketones are associated with oxidative hemoglobin damage in cats, and suggest that ketone metabolism, ie by cytochrome P450 2E1, may be a potential source of in vivo oxygen radical generation in animals with ketosis.

  1. [Surgical treatment of tumors of the carotid body with reconstruction of the internal carotid artery].

    PubMed

    Reparaz, L; Magallón, P; Riera, L; Capilla, M T; Merino, M J; Martínez, I; Hernández, A; Sáez, L; Alamo, O; Jiménez Cossío, J A

    1990-01-01

    The experience about treatment in infiltrating tumors of Carotid Corpus, III Degree (Shamblin), is presented. Different methods of carotid reconstruction, and biologic and evolutive characteristics are emphasized, discussing preoperatory study and surgical technics.

  2. Influence of the carotid rete on brain temperature in cats exposed to hot environments

    PubMed Central

    Baker, M. A.

    1972-01-01

    1. Thermocouples were chronically implanted in various intracranial and extracranial structures in adult cats. Temperature of arterial blood on the proximal and distal sides of the carotid rete was determined by measuring temperature in the aortic arch and at the anterior cerebral arteries. Temperatures of brain stem regions supplied by the carotid rete and by the vertebral—basilar system were determined by measuring temperature in the anterior hypothalamus and the caudal medulla. Nasal mucosal temperature was measured with a thermocouple implanted in the nasal cavity. 2. In a cool environment (25° C), the temperature of anterior cerebral arterial blood was lower than aortic arterial temperature. Anterior cerebral temperature showed shifts which were not present in central (aortic) arterial blood and which were clearly associated with changes in heat loss from the nasal mucosa and with the behaviour of the animal. When the cats were relaxed or in e.e.g. slow-wave sleep, the nasal mucosal temperature was high and the temperature at the anterior cerebral arteries was as much as 0·30° C less than aortic temperature. During behavioural arousal and paradoxical sleep, the nasal mucosal temperature fell and the anterior cerebral arterial temperature rose toward central arterial temperature. Shifts in hypothalamic temperature followed the changes in anterior cerebral arterial temperature. Medullary temperature was higher than aortic temperature and showed shifts which suggested that blood from the rostral circle of Willis mixed with vertebral blood in the basilar artery. 3. When the ambient temperature was raised to 40-45° C the cooling of cerebral arterial blood and brain increased as the rate of thermal panting increased. Respiratory rate increased tenfold and aortic temperature rose by 2·0-2·5 °C. Anterior cerebral arterial temperature fell below aortic temperature by as much as 1° C, hypothalamic temperature dropping in parallel with cerebral arterial

  3. Carotid body chemosensory excitation induced by nitric oxide: involvement of oxidative metabolism.

    PubMed

    Mosqueira, Matias; Iturriaga, Rodrigo

    2002-08-01

    Nitric oxide (NO) produces a dual effect on carotid body (CB) oxygen chemoreception. At low concentration, NO inhibits chemosensory response to hypoxia, while in normoxia, medium and high [NO] increases the frequency of carotid chemosensory discharges (f(x)). Since NO and peroxynitrite inhibit mitochondrial respiration, it is plausible that the NO-induced excitation may depend on the mitochondrial oxidative metabolism. To test this hypothesis, we studied the effects of oligomycin, FCCP and antimycin A that produce selective blockade of hypoxic and NaCN-induced chemosensory responses, leaving nicotinic response less affected. CBs excised from pentobarbitone-anaesthetised cats were perfused in vitro with Tyrode (P(O(2)) approximately 125 Torr, pH 7.40 at 38 degrees C). Hypoxia (P(O(2)) approximately equal 30 Torr), NaCN and nicotine (1-100 microg) and S-nitroso-N-acetylpenicillamide (SNAP, 300-600 microg) increased f(x). Oligomycin (12.5-25 microg), antimycin A (10 microg) and FCCP (5 microM) transiently increased f(x). Subsequently, chemosensory responses to hypoxia, NaCN and SNAP were reduced or abolished, while the response to nicotine was less affected. The electron donor system tetramethyl-p-phenylene diamide and ascorbate that bypasses the electron chain blockade produced by antimycin A, restores the excitatory responses to NaCN and SNAP. Present results suggest that the chemoexcitatory effect of NO depends on the integrity of mitochondrial metabolism.

  4. PO2 in the carotid body perfused and/or superfused with cell-free media.

    PubMed

    Whalen, W J; Nair, P

    1976-08-01

    We measured with a micro-O2 electrode the tissue PO2 (PtO2) in the cat carotid body (CB) to see whether it was adequately oxygenated when perfused or superfused with artificial, cell-free (c-f) solutions (pH = 7.4; temp = 35-38 degrees C). To obtain a relative measure of O2 consumption (VO2), we also measured the rate of disappearance of O2 following stoppage of the blood flow, and compared these disappearance curves with those during stoppage of the c-f perfusion solutions. In 14 cats normal (blood perfusion) PtO2 values ranged from 10 to 104 mmHG; chi = 72 +/- 4 (SE--as used throughout). During 3 h of c-f perfusion with air-equilibrated Locke's solution, PtO2 ranged from 62 to about 160 mmHg; chi = 133 +/- 4. When perfused with Fay's equilibrated with 98% O2-2% CO2 no PtO2 values in the CB were below 300 mmHg (4 cats). In eight additional cats the CB was cleared of blood then superfused with saline equilibrated with 50% O2 underneath and air-equilibrated saline over. Less than 5% of the PtO2 values found were below 5 mmHg. We conclude that most studies on the artificially perfused or superfused CB cannot be invalidated on the basis that the preparations were hypoxic. O2 disappearance curves taken during blood perfusion were significantly faster than during c-f perfusion indicating a marked reduction in VO2 with c-f perfusion.

  5. Role of Neurotransmitter Gases in the Control of the Carotid Body in Heart Failure

    PubMed Central

    Schultz, Harold D; Del Rio, Rodrigo; Ding, Yanfeng; Marcus, Noah J

    2012-01-01

    The peripheral arterial chemoreflex, arising primarily from the carotid body in most species, plays an important role in the control of breathing and in autonomic control of cardiovascular function. The peripheral chemoreflex is enhanced in heart failure patients and animal models of heart failure and contributes to the sympathetic hyperactivity and breathing instability that exacerbates the progression of the disease. Studies in animal models have shown that carotid body chemoreceptor activity is enhanced under both normoxic and hypoxic conditions in heart failure due to disruption of local mediators that control carotid body function. This brief review highlights evidence that the alterations in the gasotransmitters, nitric oxide, carbon monoxide, and hydrogen sulfide in the carotid body contribute to the exaggerated carotid body function observed in heart failure. PMID:22842006

  6. Evaluating the carotid bodies and renal nerves as therapeutic targets for hypertension.

    PubMed

    McBryde, Fiona D; Hart, Emma C; Ramchandra, Rohit; Paton, Julian F R

    2017-05-01

    Despite the plethora of current treatment options, hypertension remains a difficult condition to adequately control, and there is a pressing need for novel therapeutic strategies. The carotid body has recently become the focus of considerable interest as a potential novel treatment target in essential hypertension. Herein, we appraise the current literature suggesting that the carotid body plays an important causative role to generate sympathetic overactivity and drive increases in arterial pressure, in animal models of hypertension. We also review evidence from human studies showing cardiovascular benefits to the transient inactivation, or surgical removal of carotid bodies, and evaluate the potential benefits of pre-screening to identify patients likely to respond to carotid body-targeted therapy. Finally, given that a high proportion of patients who have undergone renal nerve ablation procedures remain hypertensive, we examine whether the renal nerves are necessary for the drop in blood pressure seen with carotid body removal. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Cerebral foreign body reaction after carotid aneurysm stenting

    PubMed Central

    Lorentzen, Anastasia Orlova; Nome, Terje; Bakke, Søren Jacob; Scheie, David; Stenset, Vidar

    2016-01-01

    Flow diverter stents are new important tools in the treatment of large, giant, or wide-necked aneurysms. Their delivery and positioning may be difficult due to vessel tortuosity. Common adverse events include intracranial hemorrhage and ischemic stroke, which usually occurs within the same day, or the next few days after the procedure. We present a case where we encountered an unusual intracerebral complication several months after endovascular treatment of a large left internal carotid artery aneurysm, and where brain biopsy revealed foreign body reaction to hydrophilic polymer fragments distally to the stent site. Although previously described, embolization of polymer material from intravascular equipment is rare. We could not identify any other biopsy verified case in the literature, with this particular presentation of intracerebral polymer embolization – a multifocal inflammation spread out through the white matter of one hemisphere without hemorrhage or ischemic changes. PMID:26510943

  8. Contribution of endothelin-1 to the enhanced carotid body chemosensory responses induced by chronic intermittent hypoxia.

    PubMed

    Rey, Sergio; Del Rio, Rodrigo; Iturriaga, Rodrigo

    2006-05-01

    Chronic intermittent hypoxia (CIH) enhances carotid body (CB) chemosensory responses to acute hypoxia. We tested the hypothesis that endothelin-1 (ET-1), an excitatory modulator of CB chemoreception may contribute to the enhanced CB chemosensory responses in cats exposed to cyclic hypoxic episodes repeated during 8 h for 4 days. Accordingly, we measured the ET-1 immunoreactivity (ET-ir) in the CB and plasma. Using a perfused CB preparation, we studied the effects of exogenous ET-1 and bosentan, a non-selective endothelin receptor type A and B antagonist, on the frequency of chemosensory discharges (f(x)) during normoxia, mild and severe hypoxia. We found that CIH increased ET-ir in the CB by approximately 10-fold leaving ET-1 plasma levels unchanged. Application of ET-1 to control and CIH-treated CBs produced long-lasting dose-dependent increases in f(x), although the dose-response curve showed a rightward-shift in the CIH-treated CBs. CIH increased baseline f(x) and hypoxic chemosensory responses, which were reduced by 50 microM bosentan in CBs from CIH-treated cats. Present results suggest that a local increase of ET-1 in the CB may contribute to the enhanced chemosensory responses induced by CIH predominantly through a vasomotor mechanism.

  9. Guinea Pig Oxygen-Sensing and Carotid Body Functional Properties.

    PubMed

    Gonzalez-Obeso, Elvira; Docio, Inmaculada; Olea, Elena; Cogolludo, Angel; Obeso, Ana; Rocher, Asuncion; Gomez-Niño, Angela

    2017-01-01

    Mammals have developed different mechanisms to maintain oxygen supply to cells in response to hypoxia. One of those mechanisms, the carotid body (CB) chemoreceptors, is able to detect physiological hypoxia and generate homeostatic reflex responses, mainly ventilatory and cardiovascular. It has been reported that guinea pigs, originally from the Andes, have a reduced ventilatory response to hypoxia compared to other mammals, implying that CB are not completely functional, which has been related to genetically/epigenetically determined poor hypoxia-driven CB reflex. This study was performed to check the guinea pig CB response to hypoxia compared to the well-known rat hypoxic response. These experiments have explored ventilatory parameters breathing different gases mixtures, cardiovascular responses to acute hypoxia, in vitro CB response to hypoxia and other stimuli and isolated guinea pig chemoreceptor cells properties. Our findings show that guinea pigs are hypotensive and have lower arterial pO2 than rats, probably related to a low sympathetic tone and high hemoglobin affinity. Those characteristics could represent a higher tolerance to hypoxic environment than other rodents. We also find that although CB are hypo-functional not showing chronic hypoxia sensitization, a small percentage of isolated carotid body chemoreceptor cells contain tyrosine hydroxylase enzyme and voltage-dependent K(+) currents and therefore can be depolarized. However hypoxia does not modify intracellular Ca(2+) levels or catecholamine secretion. Guinea pigs are able to hyperventilate only in response to intense acute hypoxic stimulus, but hypercapnic response is similar to rats. Whether other brain areas are also activated by hypoxia in guinea pigs remains to be studied.

  10. Guinea Pig Oxygen-Sensing and Carotid Body Functional Properties

    PubMed Central

    Gonzalez-Obeso, Elvira; Docio, Inmaculada; Olea, Elena; Cogolludo, Angel; Obeso, Ana; Rocher, Asuncion; Gomez-Niño, Angela

    2017-01-01

    Mammals have developed different mechanisms to maintain oxygen supply to cells in response to hypoxia. One of those mechanisms, the carotid body (CB) chemoreceptors, is able to detect physiological hypoxia and generate homeostatic reflex responses, mainly ventilatory and cardiovascular. It has been reported that guinea pigs, originally from the Andes, have a reduced ventilatory response to hypoxia compared to other mammals, implying that CB are not completely functional, which has been related to genetically/epigenetically determined poor hypoxia-driven CB reflex. This study was performed to check the guinea pig CB response to hypoxia compared to the well-known rat hypoxic response. These experiments have explored ventilatory parameters breathing different gases mixtures, cardiovascular responses to acute hypoxia, in vitro CB response to hypoxia and other stimuli and isolated guinea pig chemoreceptor cells properties. Our findings show that guinea pigs are hypotensive and have lower arterial pO2 than rats, probably related to a low sympathetic tone and high hemoglobin affinity. Those characteristics could represent a higher tolerance to hypoxic environment than other rodents. We also find that although CB are hypo-functional not showing chronic hypoxia sensitization, a small percentage of isolated carotid body chemoreceptor cells contain tyrosine hydroxylase enzyme and voltage-dependent K+ currents and therefore can be depolarized. However hypoxia does not modify intracellular Ca2+ levels or catecholamine secretion. Guinea pigs are able to hyperventilate only in response to intense acute hypoxic stimulus, but hypercapnic response is similar to rats. Whether other brain areas are also activated by hypoxia in guinea pigs remains to be studied. PMID:28533756

  11. Carotid body, insulin, and metabolic diseases: unraveling the links

    PubMed Central

    Conde, Sílvia V.; Sacramento, Joana F.; Guarino, Maria P.; Gonzalez, Constancio; Obeso, Ana; Diogo, Lucilia N.; Monteiro, Emilia C.; Ribeiro, Maria J.

    2014-01-01

    The carotid bodies (CB) are peripheral chemoreceptors that sense changes in arterial blood O2, CO2, and pH levels. Hypoxia, hypercapnia, and acidosis activate the CB, which respond by increasing the action potential frequency in their sensory nerve, the carotid sinus nerve (CSN). CSN activity is integrated in the brain stem to induce a panoply of cardiorespiratory reflexes aimed, primarily, to normalize the altered blood gases, via hyperventilation, and to regulate blood pressure and cardiac performance, via sympathetic nervous system (SNS) activation. Besides its role in the cardiorespiratory control the CB has been proposed as a metabolic sensor implicated in the control of energy homeostasis and, more recently, in the regulation of whole body insulin sensitivity. Hypercaloric diets cause CB overactivation in rats, which seems to be at the origin of the development of insulin resistance and hypertension, core features of metabolic syndrome and type 2 diabetes. Consistent with this notion, CB sensory denervation prevents metabolic and hemodynamic alterations in hypercaloric feed animal. Obstructive sleep apnea (OSA) is another chronic disorder characterized by increased CB activity and intimately related with several metabolic and cardiovascular abnormalities. In this manuscript we review in a concise manner the putative pathways linking CB chemoreceptors deregulation with the pathogenesis of insulin resistance and arterial hypertension. Also, the link between chronic intermittent hypoxia (CIH) and insulin resistance is discussed. Then, a final section is devoted to debate strategies to reduce CB activity and its use for prevention and therapeutics of metabolic diseases with an emphasis on new exciting research in the modulation of bioelectronic signals, likely to be central in the future. PMID:25400585

  12. Regulation of the common carotid arterial blood flow by nicotinic receptors in the medulla of cats

    PubMed Central

    Gong, C-L; Chiu, Y-T; Lin, N-N; Cheng, C-C; Lin, S-Z; Lee, T J-F; Kuo, J-S

    2006-01-01

    Background and purpose: Actions of glutamate and serotonin on their respective receptors in the dorsal facial area (DFA) of the medulla are known to regulate common carotid arterial (CCA) blood flow in cats. Less is known about acetylcholine action on its nicotinic receptor (nAChR) subtypes in the DFA for regulation of CCA blood flow and this aspect was investigated. Experimental approach: Nicotinic and muscarinic agonists and antagonists were microinjected into the DFA through a three-barrel tubing in anesthetized cats. Results: CCA blood flow was dose-dependently increased by nicotine (a non-selective nAChR agonist) and choline (a selective α7-nAChR agonist). These effects of nicotine were attenuated by α-bungarotoxin (an α7-nAChR antagonist), methyllycaconitine (an α7-nAChR antagonist), mecamylamine (a relatively selective α3β4-nAChR antagonist) and dihydro-β-erythroidine (a relatively selective α4β2-nAChR antagonist). The choline-induced flow increase was attenuated by α-bungarotoxin and mecamylamine, but not by dihydro-β-erythroidine. Muscarinic agonists (muscarine and methacholine) and antagonist (atropine) affected neither the basal nor the nicotine-induced increase in the CCA blood flow. Conclusions and implications: Functional α7, α4β2, and α3β4 subunits of the nAChR appear to be present on the DFA neurons. Activations of these receptors increase the CCA blood flow. The present findings do not preclude the presence of other nAChRs subunits. Muscarinic receptors, if any, on the DFA are not involved in regulation of the CCA blood flow. Various subtypes of nAChRs in the DFA may mediate regulation of the CCA and cerebral blood flows. PMID:16894347

  13. Traumatic body wall herniation in 36 dogs and cats.

    PubMed

    Shaw, Scott R; Rozanski, Elizabeth A; Rush, John E

    2003-01-01

    Traumatic body wall hernias (TBWH) are serious sequelae to traumatic injury in dogs and cats. During the study period, 26 dogs and 10 cats with surgically managed TBWH were identified. Five cases (four dogs, one cat) did not have their hernias identified during the first 24 hours of hospitalization. Bite wounds were the most common cause of TBWH, accounting for 54% of canine and 40% of feline hernias. Twelve cases (nine dogs, three cats) had serious intra-abdominal injuries diagnosed in addition to their TBWH. Seventy-three percent of dogs and 80% of cats survived to hospital discharge. In addition, the authors report the occurrence of a unique cause of herniation, termed an autopenetrating hernia.

  14. Does yawning increase arousal through mechanical stimulation of the carotid body?

    PubMed

    Matikainen, Jorma; Elo, Hannu

    2008-01-01

    Yawning is a stereotyped event that occurs in humans and animals from fish to mammals, but neither its mechanisms nor its functions are entirely known. Its widespread nature suggests that it has important physiological functions. It is associated with stretching of muscles in a large area, but the function of this stretching is understood far from completely. It has been proposed that yawning increases arousal and that it is an arousal defense reflex, whose aim is to reverse brain hypoxia. Whilst yawning has been speculated to have an important role in reversing hypoxia, there is a structure in the neck that is known to be intimately involved in the regulation of oxygen homeostasis, namely the carotid body. It senses acute changes in oxygen levels. In spite of this, a connection has never been proposed either between the carotid body and arousal, or between yawning and the carotid body. We propose that yawning stimulates mechanically the carotid body (and possibly other structures in the neck). We further propose that this stimulation gives rise to increased arousal, alertness and wakefulness and that one important physiological function of yawning is increase of arousal through this stimulation. We also propose that mechanical effects on the shunt system of the carotid body may be involved in this stimulation. Our hypothesis is supported by several facts. For example, yawning causes movements and compressions that may affect the carotid body that is situated strategically at the bifurcation of the common carotid artery. Thus, yawning may stimulate the carotid body. The carotid body is highly vascular and compressions may affect its shunt system and blood flow and for example give rise to release of hormones or other substances. Also several facts related to situations where people yawn or do not yawn support our hypothesis and are discussed. Further support comes from facts related to somnogenic substances, hormones and transmitters, and from facts related to the

  15. Adrenergic mechanisms in oxygen chemoreception in the cat aortic body.

    PubMed

    Mulligan, E; Lahiri, S; Mokashi, A; Matsumoto, S; McGregor, K H

    1986-03-01

    Sixteen cats were studied to test the hypothesis that oxygen chemoreception in the cat aortic body is dependent on the beta-adrenergic mechanism. The chemoreceptor activity was measured from a few aortic chemoreceptor afferents in each cat, anesthetized with alpha-chloralose (60 mg X kg-1). Three types of experiments were conducted. Aortic chemoreceptor responses to steady-state hypoxia (PaO2 range, 100-30 Torr) were measured (a) before and during intravenous infusion of the beta-receptor agonist, isoproterenol (0.5 micrograms X kg-1) in nine spontaneously breathing cats, and (b) before and after intravenous injection of the beta-receptor antagonist, propranolol (1 mg X kg-1) in seven cats which were paralyzed and artificially ventilated. In the third category (c) the stimulatory effect of hypotension on aortic chemoreceptor activity was measured in six of the seven cats in group (b) before and after propranolol injection. Isoproterenol infusion only moderately stimulated aortic chemoreceptor activity. This stimulation was blocked by propranolol. However, propranolol did not attenuate aortic chemoreceptor responses to hypoxia or to hypotension. We conclude that the beta-receptor adrenergic mechanism does not mediate oxygen chemoreception in the cat aortic body.

  16. Correlation between adenosine triphosphate levels, dopamine release and electrical activity in the carotid body: support for the metabolic hypothesis of chemoreception.

    PubMed

    Obeso, A; Almaraz, L; Gonzalez, C

    1985-11-25

    An unsolved issue for the arterial chemoreceptors is the mechanism by which hypoxia and other natural stimuli lead to an increase of activity in the carotid sinus nerve. According to the 'metabolic hypothesis', the hypoxic activation of the carotid body (CB) is mediated by a decrease of the ATP levels in the type I cells, which then release a neurotransmitter capable of exciting the sensory nerve endings. Using an in vitro preparation of cat CB, we report that ATP levels in the CB do in fact decrease when the organs are exposed to moderate, short lasting hypoxia (5 min 20% O2). Additionally, we found that decreases in ATP levels induced by 2-deoxyglucose (2 mM) or sodium cyanide (0.1 mM) are closely correlated with dopamine release from type I cells and electrical activity in the carotid sinus nerve elicited by these agents. The possible cause-effect relationship of these events is discussed.

  17. Selective Expression of Galanin in Neuronal-Like Cells of the Human Carotid Body.

    PubMed

    Di Giulio, Camillo; Marconi, Guya Diletta; Zara, Susi; Di Tano, Andrea; Porzionato, Andrea; Pokorski, Mieczyslaw; Cataldi, Amelia; Mazzatenta, Andrea

    2015-01-01

    The carotid body is a neural-crest-derived organ devoted to respiratory homeostasis through sensing changes in blood oxygen levels. The sensory units are the glomeruli composed of clusters of neuronal-like (type I) cells surrounded by glial-like (type II) cells. During chronic hypoxia, the carotid body shows growth, with increasing neuronal-like cell numbers. We are interested in the signals involved in the mechanisms that underlie such response, because they are not well understood and described. Considering that, in literature, galanin is involved in neurotrophic or neuroprotective role in cell proliferation and is expressed in animal carotid body, we investigated its expression in human. Here, we have shown the expression and localisation of galanin in the human carotid body.

  18. Role of TrkB during the postnatal development of the rat carotid body.

    PubMed

    Bavis, Ryan W; Blegen, Halward J; Logan, Sarah; Fallon, Sarah C; McDonough, Amy B

    2015-12-01

    Brain-derived neurotrophic factor (BDNF) supports innervation of the carotid body by neurons projecting from the petrosal ganglion. Although carotid body glomus cells also express TrkB, BDNF's high affinity receptor, the role of BDNF in carotid body growth and O2 sensitivity has not been studied. Neonatal rats were treated with the TrkB antagonist K252a (100 μg kg(-1), i.p., b.i.d.) or vehicle on postnatal days P0-P6 and studied on P7. Carotid body volume was decreased by 35% after chronic K252a (P<0.001); a reduction in carotid body size was also elicited using the more selective TrkB antagonist ANA-12 (500 μg kg(-1), i.p., b.i.d.). In contrast, single-unit chemoafferent responses to 5% O2, measured in vitro, were unaffected by chronic K252a administration. Normoxic and hypoxic ventilation, measured by head-body plethysmography, were also normal after chronic K252a administration, but acute K252a administration produced a slower, deeper breathing pattern during the transition into hypoxia. These data suggest that BDNF regulates postnatal carotid body growth but does not influence the development of glomus cell O2 sensitivity. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Role of TrkB during the postnatal development of the rat carotid body

    PubMed Central

    Bavis, Ryan W.; Blegen, Halward J.; Logan, Sarah; Fallon, Sarah C.; McDonough, Amy B.

    2015-01-01

    Brain-derived neurotrophic factor (BDNF) supports innervation of the carotid body by neurons projecting from the petrosal ganglion. Although carotid body glomus cells also express TrkB, BDNF’s high affinity receptor, the role of BDNF in carotid body growth and O2 sensitivity has not been studied. Neonatal rats were treated with the TrkB antagonist K252a (100 μg kg−1, i.p., b.i.d.) or vehicle on postnatal days P0–P6 and studied on P7. Carotid body volume was decreased by 35% after chronic K252a (P<0.001); a reduction in carotid body size was also elicited using the more selective TrkB antagonist ANA-12 (500 μg kg−1, i.p., b.i.d.). In contrast, single-unit chemoafferent responses to 5% O2, measured in vitro, were unaffected by chronic K252a administration. Normoxic and hypoxic ventilation, measured by head-body plethysmography, were also normal after chronic K252a administration, but acute K252a administration produced a slower, deeper breathing pattern during the transition into hypoxia. These data suggest that BDNF regulates postnatal carotid body growth but does not influence the development of glomus cell O2 sensitivity. PMID:26222433

  20. Evaluation of Body Weight, Body Condition, and Muscle Condition in Cats with Hyperthyroidism.

    PubMed

    Peterson, M E; Castellano, C A; Rishniw, M

    2016-11-01

    The contribution of fat loss versus muscle wasting to the loss of body weight seen in hyperthyroid cats is unknown. To investigate body weight, body condition score (BCS), and muscle condition score (MCS) in hyperthyroid cats. Four hundred sixty-two cats with untreated hyperthyroidism, 117 of which were reevaluated after treatment. Prospective cross-sectional and before-after studies. Untreated hyperthyroid cats had body composition evaluated (body weight, BCS, and MCS). A subset of these cats were reevaluated 3-12 months after treatment when euthyroid. Pretreatment body weight (median, 4.36 kg; IQR, 3.5 to 5.2 kg) was lower than premorbid weight (5.45 kg; IQR, 4.6 to 6.4 kg, P < .0001) recorded 1-2 years before diagnosis. 154 (35.3%) cats were thin or emaciated; 357 (77.3%) had loss of muscle mass. Cats showed increases in body weight (median, 4.1 kg to 5.0 kg), BCS (median, 3/5 to 3.5/5), and MCS (2/3 to 3/3) after treatment (P < .001), but mild-to-moderate muscle wasting persisted in 45% of treated cats. Most hyperthyroid cats lose body weight but maintain an ideal or overweight BCS, with only a third being underweight. As in human hyperthyroid patients, this weight loss is associated with muscle wasting, which affects >75% of hyperthyroid cats. Successful treatment leads to weight gain and increase of BCS in most cats, but almost half fail to regain normal muscle mass. Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  1. Carotid body chemoreception in the absence and presence of CO2-HCO3-.

    PubMed

    Iturriaga, R; Lahiri, S

    1991-12-24

    Carotid body (CB) chemosensory responses to natural and pharmacological stimuli were studied in vitro in the presence and nominal absence of CO2-HCO3- in the perfusion-superfusion media. The CBs obtained from cats (n = 10), anesthetized with sodium pentobarbitone, were simultaneously perfused and superfused with a modified Tyrode solution at 36.5 +/- 0.5 degrees C, equilibrated respectively with PO2 of 120 and less than 20 Torr. The Tyrode, nominally free of CO2-HCO3- (HEPES-NaOH, pH 7.38, 310 mOsm), was used first. Subsequently the Tyrode containing HEPES-HCO3-, equilibrated with PCO2 of 36.8 Torr (pH 7.38) was used. Chemosensory discharges were recorded from the carotid sinus nerve. Both hypoxia (PO2 = 20-25 Torr) and ischemic hypoxia stimulated the discharge in the absence and presence of CO2-HCO3-. However, the presence of CO2-HCO3- significantly raised the baseline activity, augmented the speed, sensitivity and the maximal responses to both types of hypoxia. Hypercapnic perfusate (PCO2 = 65 Torr at pH 7.17) produced a peak response equally promptly in the absence and presence of CO2-HCO3- in the ongoing perfusate but generated a larger and more sustained response. Presence of CO2-HCO3- strongly potentiated the responses to cyanide (10(-10)-10(-7) mol) but less strikingly the responses to nicotine (10(-11)-10(-8) mol). Thus, the extracellular CO2-HCO3- significantly improved the response to hypoxia but was not essential for O2 chemoreception. The underlying mechanisms of the effect of CO2-HCO3- is likely to be mediated by the Cl(-)-HCO3- anion exchanger in the pH regulation of glomus cells.

  2. Ultrastructure of the carotid body of the goat.

    PubMed

    Abdel-Magied, E M; Taha, A A

    1995-09-01

    The carotid body of the goat was found to be a small oval or rounded parenchymatous organ. It was characterized by its profound vascularity. Delicate septa divided the parenchyma into small feebly defined lobules. Electron microscopy revealed that the parenchyma comprised type I cells, type II cells, nerve endings, axons and fenestrated dilated capillaries. Type I cells were characterized with electron dense-cored vesicles. They showed variations in size and concentration of the dense-cored vesicles and number of mitochondria. The possibility that these variations are reflections of different stages of activity is discussed. Type II cells were less numerous than type I cells, relatively small and devoid of dense-cored vesicles. They usually surrounded small groups of type I cells and associated nerve endings and axons. Presumptive afferent nerve endings characterized with many clear vesicles, occasional large granular vesicles and varying numbers of slender mitochondria, lay apposed to type I cells. Nerve endings of this kind showed afferent and efferent synaptic junctions with type I cells. Presumptive sympathetic efferent endings were occasionally seen within the lobules but never lay apposed to type I cells or afferent nerve ending.

  3. Mechanisms of carotid body chemoreflex dysfunction during heart failure

    PubMed Central

    Schultz, Harold D.; Marcus, Noah J.; Del Rio, Rodrigo

    2015-01-01

    Recent advances have drawn interest in the potential for carotid body (CB) ablation or desensitization as an effective strategy for clinical treatment and management of cardio-respiratory diseases including hypertension, heart failure, diabetes mellitus, metabolic syndrome, and renal failure. These disease states have in common sympathetic overactivity, which plays an important role in the development and progression of the disease and is often associated with breathing dysregulation, which in turn likely mediates or aggravates the autonomic imbalance. Evidence from both chronic heart failure (CHF) patients and animal models indicates that the CB chemoreflex is enhanced in CHF and contributes to the tonic elevation in sympathetic activity and the development of periodic breathing associated with the disease. Although this maladaptive change likely derives from altered function at all levels of the reflex arc, a tonic increase in afferent activity from CB glomus cells is likely to be a main driving force. This report will focus on our understanding of mechanisms that alter CB function in CHF and their potential translational impact on treatment of CHF. PMID:25398713

  4. Carotid body tumors: Surgical experience in 215 cases.

    PubMed

    Pacheco-Ojeda, Luis A

    2017-09-01

    Carotid body tumors (CBT) are very unusual neck lesions. However, at high altitudes, they are less rarely found. This study intended to review our experience in diagnosis and surgical treatment of these lesions. Among 242 clinically diagnosed CBT, 215 tumors, arising in and retrospectively studied. All patients came from the Andean plateaux. Mean age was 52.5 years, 180 were females, and mean size was 4.21 cm. Shamblin type distribution, described in 187 patients, was: Type I 29(15%), type II 118(63%) and type III 40(22%). A correct preoperative diagnosis of CBT was made in 95% of the patients, based on clinical grounds and imaging studies. Complete CBT resection was performed in 209 tumors (97%). Twenty-three (11%) accidental preoperative vessel injuries were successfully repaired. Preoperative blood transfusion was used in only 16 cases. There was no operative mortality. Postoperative complications occurred in 59(27.5%) procedures, mostly minor and related to cranial nerve dysfunction. No stroke occurred in any patient. Seven (3%) cases were malignant. A systematic surgical technique allowed us to perform a complete CBT resection in most patients, unusual operative vascular accidents, low morbidity and no mortality. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  5. General redox environment and carotid body chemoreceptor function.

    PubMed

    Agapito, Maria Teresa; Sanz-Alfayate, Gloria; Gomez-Niño, Angela; Gonzalez, Constancio; Obeso, Ana

    2009-03-01

    Carotid body (CB) chemoreceptor cells detect physiological levels of hypoxia and generate a hyperventilation, homeostatic in nature, aimed to minimize the deleterious effects of hypoxia. Intimate mechanisms involved in oxygen sensing in chemoreceptor cells remain largely unknown, but reactive oxygen species (ROS) had been proposed as mediators of this process. We have determined glutathione levels and calculated glutathione redox potential (E(GSH); indicator of the general redox environment of cells) in rat diaphragms incubated in the presence of oxidizing agents of two types: nonpermeating and permeating through cell membranes; in the latter group, unspecific oxidants and inhibitors of ROS-disposing enzymes were used. Selected concentrations of oxidizing agents were tested for their ability to modify the normoxic and hypoxic activity of chemoreceptor cells measured in vitro as their rate of release of neurotransmitters. Results evidence variable relationships between E(GSH) and the activity of chemoreceptor cells. The independence of chemoreceptor cell activity from the E(GSH) would imply that the ability of the CB to play its homeostatic role is largely preserved in any pathological or toxicological contingency causing oxidative stress. Consistent with this suggestion, it was also found that CB-mediated hypoxic hyperventilation was not altered by treatment of intact animals with agents that markedly decreased the E(GSH) in all tissues assayed.

  6. Carotid body oxygen sensing and adaptation to hypoxia.

    PubMed

    López-Barneo, José; Macías, David; Platero-Luengo, Aida; Ortega-Sáenz, Patricia; Pardal, Ricardo

    2016-01-01

    The carotid body (CB) is the principal arterial chemoreceptor that mediates the hyperventilatory response to hypoxia. Our understanding of CB function and its role in disease mechanisms has progressed considerably in the last decades, particularly in recent years. The sensory elements of the CB are the neuron-like glomus cells, which contain numerous transmitters and form synapses with afferent sensory fibers. The activation of glomus cells under hypoxia mainly depends on the modulation of O2-sensitive K(+) channels which leads to cell depolarization and the opening of Ca(2+) channels. This model of sensory transduction operates in all mammalian species studied thus far, including man. However, the molecular mechanisms underlying the modulation of ion channel function by changes in the O2 level are as yet unknown. The CB plays a fundamental role in acclimatization to sustained hypoxia. Mice with CB atrophy or patients who have undergone CB resection due to surgical treatments show a marked intolerance to even mild hypoxia. CB growth under hypoxia is supported by the existence of a resident population of neural crest-derived stem cells of glia-like phenotype. These stem cells are not highly affected by exposure to low O2 tension; however, there are abundant synapse-like contacts between the glomus cells and stem cells (chemoproliferative synapses), which may be needed to trigger progenitor cell proliferation and differentiation under hypoxia. CB hypo- or hyper-activation may also contribute to the pathogenesis of several prevalent human diseases.

  7. Magnetic resonance and computed tomography imaging of a carotid body tumor in a dog

    PubMed Central

    2012-01-01

    A 5-year-old castrated male Labrador Retriever was presented to a referring veterinarian for a swelling in the neck region. Based on the results of histopathology, a carotid body tumor, was diagnosed. The dog was referred to a medical imaging unit for further staging and follow up. This report describes the magnetic resonance (MR) and computed tomographic (CT) appearance of a carotid body tumor. PMID:22507757

  8. Magnetic resonance and computed tomography imaging of a carotid body tumor in a dog.

    PubMed

    Kromhout, Kaatje; Gielen, Ingrid; De Cock, Hilde E V; Van Dyck, Kristof; van Bree, Henri

    2012-04-16

    A 5-year-old castrated male Labrador Retriever was presented to a referring veterinarian for a swelling in the neck region. Based on the results of histopathology, a carotid body tumor, was diagnosed. The dog was referred to a medical imaging unit for further staging and follow up. This report describes the magnetic resonance (MR) and computed tomographic (CT) appearance of a carotid body tumor.

  9. A simple technique to achieve bloodless excision of carotid body tumors.

    PubMed

    Spinelli, Francesco; Massara, Mafalda; La Spada, Michele; Stilo, Francesco; Barillà, David; De Caridi, Giovanni

    2014-05-01

    We describe a technique for Shamblin II-III carotid body tumor (CBT) resection to reduce bleeding and neurologic complications during surgery. The technique was based on the fact that CBTs are supplied almost exclusively from the external carotid artery. Therefore, we carefully isolated the origin of the external carotid artery and its distal branches outside the tumor and temporarily clamped all of these vessels after heparin administration. This allowed a safe and bloodless resection as the tumor was dissected from the internal carotid artery in the usual subadventitial plane. The internal carotid artery was never clamped, and respect of peripheral nerves was warranted in the clean and bloodless field. From 2007 to 2010, we treated 11 patients with a CBT: six had a Shamblin II and five had a Shamblin III lesion. Neither perioperative neurologic events nor recurrences occurred after a mean follow-up of 42 months.

  10. Baroreflex activation therapy lowers arterial pressure without apparent stimulation of the carotid bodies.

    PubMed

    Alnima, Teba; Goedhart, Emilie J B M; Seelen, Randy; van der Grinten, Chris P M; de Leeuw, Peter W; Kroon, Abraham A

    2015-06-01

    Carotid baroreflex activation therapy produces a sustained fall in blood pressure in patients with resistant hypertension. Because the activation electrodes are implanted at the level of the carotid sinus, it is conceivable that the nearby located carotid body chemoreceptors are stimulated as well. Physiological stimulation of the carotid chemoreceptors not only stimulates respiration but also increases sympathetic activity, which may counteract the effects of baroreflex activation. The aim of this exploratory study is to investigate whether there is concomitant carotid chemoreflex activation during baroreflex activation therapy. Fifteen participants with the Rheos system were included in this single-center study. At arrival at the clinic, the device was switched off for 2 hours while patients were at rest. Subsequently, the device was switched on at 6 electric settings of high and low frequencies and amplitudes. Respiration and blood pressure measurements were performed during all device activation settings. Multilevel statistical models were adjusted for age, sex, body mass index, antihypertensive therapeutic index, sleep apnea, coronary artery disease, systolic blood pressure, and heart rate. There was no change in end-tidal carbon dioxide, partial pressure of carbon dioxide, breath duration, and breathing frequency during any of the electric settings with the device. Nevertheless, mean arterial pressure showed a highly significant decrease during electric activation (P<0.001). Carotid baroreflex activation therapy using the Rheos system did not stimulate respiration at several electric device activation energies, which suggests that there is no appreciable coactivation of carotid body chemoreceptors during device therapy. © 2015 American Heart Association, Inc.

  11. Neonatal Maternal Separation Augments Carotid Body Response to Hypoxia in Adult Males but Not Female Rats

    PubMed Central

    Soliz, Jorge; Tam, Rose; Kinkead, Richard

    2016-01-01

    Perinatal exposure to adverse experiences disrupts brain development, including the brainstem network that regulates breathing. At adulthood, rats previously subjected to stress (in the form of neonatal maternal separation; NMS) display features reported in patients suffering from sleep disordered breathing, including an increased hypoxic ventilatory response and hypertension. This effect is also sex-specific (males only). Based on these observations, we hypothesized that NMS augments the carotid body's O2-chemosensitivity. Using an isolated and perfused ex vivo carotid body preparation from adult rats we compared carotid sinus nerve (CSN) responses to hypoxia and hypercapnia in carotid bodies harvested from adult rats that either experienced control conditions (no experimental manipulation) or were subjected to NMS (3 h/day from postnatal days 3 to 12). In males, the CSN response to hypoxia measured in preparations from NMS males was 1.5 fold higher than controls. In control rats, the female's response was similar to that of males; however, the increase in CSN activity measured in NMS females was 3.0 times lower than controls. The CSN response to hypercapnia was not influenced by stress or sex. We conclude that NMS is sufficient to have persistent and sex-specific effects on the carotid body's response to hypoxia. Because NMS also has sex-specific effects on the neuroendocrine response to stress, we propose that carotid body function is influenced by stress hormones. This, in turn, leads to a predisposition toward cardio-respiratory disorders. PMID:27729873

  12. Preoperative embolization in carotid body tumor surgery: is it required?

    PubMed

    Zeitler, Daniel M; Glick, Joelle; Har-El, Gady

    2010-05-01

    We compared estimated blood loss (EBL) in patients who underwent surgical excision of carotid body tumors (CBTs) after preoperative superselective angiography with embolization (PSE) with that in patients who underwent excision of CBTs without PSE. We performed a retrospective chart review of a consecutive case series in a single surgeon's practice within an academic tertiary care medical center. Twenty-five patients underwent surgical resection of a CBT from 1989 to 2009. From 1989 to 1996, 10 consecutive patients had PSE of the CBT, whereas the subsequent 15 patients (1996 to 2009) had no PSE. Demographic data including age, sex, and tumor size were collected. The EBL was obtained from intraoperative records and operative notes dictated at the time of surgery. Tumor size was based on preoperative radiographic measurements by a senior radiologist and the surgeon. In the 10 patients with PSE, the mean age was 41 years (range, 22 to 72 years) and the mean tumor size was 4.8 cm (range, 2.9 to 8.3 cm). The mean EBL was 305 mL (range, 50 to 1,000 mL); 2 patients had an EBL of more than 400 mL. In the 15 patients without PSE, the mean age was 43.7 years (range, 20 to 75 years) and the mean tumor size was 4.4 cm (range, 2.8 to 7.9 cm). The mean EBL was 265.6 mL (range, 40 to 900 mL); 2 patients had an EBL of more than 400 mL. There were no significant differences between the 2 groups with regard to age, tumor size, or EBL. Preoperative superselective angiography with embolization of a CBT does not lead to a significant reduction in intraoperative EBL.

  13. Carotid body potentiation during chronic intermittent hypoxia: implication for hypertension

    PubMed Central

    Del Rio, Rodrigo; Moya, Esteban A.; Iturriaga, Rodrigo

    2014-01-01

    Autonomic dysfunction is involved in the development of hypertension in humans with obstructive sleep apnea, and animals exposed to chronic intermittent hypoxia (CIH). It has been proposed that a crucial step in the development of the hypertension is the potentiation of the carotid body (CB) chemosensory responses to hypoxia, but the temporal progression of the CB chemosensory, autonomic and hypertensive changes induced by CIH are not known. We tested the hypothesis that CB potentiation precedes the autonomic imbalance and the hypertension in rats exposed to CIH. Thus, we studied the changes in CB chemosensory and ventilatory responsiveness to hypoxia, the spontaneous baroreflex sensitivity (BRS), heart rate variability (HRV) and arterial blood pressure in pentobarbital anesthetized rats exposed to CIH for 7, 14, and 21 days. After 7 days of CIH, CB chemosensory and ventilatory responses to hypoxia were enhanced, while BRS was significantly reduced by 2-fold in CIH-rats compared to sham-rats. These alterations persisted until 21 days of CIH. After 14 days, CIH shifted the HRV power spectra suggesting a predominance of sympathetic over parasympathetic tone. In contrast, hypertension was found after 21 days of CIH. Concomitant changes between the gain of spectral HRV, BRS, and ventilatory hypoxic chemoreflex showed that the CIH-induced BRS attenuation preceded the HRV changes. CIH induced a simultaneous decrease of the BRS gain along with an increase of the hypoxic ventilatory gain. Present results show that CIH-induced persistent hypertension was preceded by early changes in CB chemosensory control of cardiorespiratory and autonomic function. PMID:25429271

  14. Revisiting cAMP signaling in the carotid body

    PubMed Central

    Nunes, Ana R.; Holmes, Andrew P.; Conde, Sílvia V.; Gauda, Estelle B.; Monteiro, Emília C.

    2014-01-01

    Chronic carotid body (CB) activation is now recognized as being essential in the development of hypertension and promoting insulin resistance; thus, it is imperative to characterize the chemotransduction mechanisms of this organ in order to modulate its activity and improve patient outcomes. For several years, and although controversial, cyclic adenosine monophosphate (cAMP) was considered an important player in initiating the activation of the CB. However, its relevance was partially displaced in the 90s by the emerging role of the mitochondria and molecules such as AMP-activated protein kinase and O2-sensitive K+ channels. Neurotransmitters/neuromodulators binding to metabotropic receptors are essential to chemotransmission in the CB, and cAMP is central to this process. cAMP also contributes to raise intracellular Ca2+ levels, and is intimately related to the cellular energetic status (AMP/ATP ratio). Furthermore, cAMP signaling is a target of multiple current pharmacological agents used in clinical practice. This review (1) provides an outline on the classical view of the cAMP-signaling pathway in the CB that originally supported its role in the O2/CO2 sensing mechanism, (2) presents recent evidence on CB cAMP neuromodulation and (3) discusses how CB activity is affected by current clinical therapies that modify cAMP-signaling, namely dopaminergic drugs, caffeine (modulation of A2A/A2B receptors) and roflumilast (PDE4 inhibitors). cAMP is key to any process that involves metabotropic receptors and the intracellular pathways involved in CB disease states are likely to involve this classical second messenger. Research examining the potential modification of cAMP levels and/or interactions with molecules associated with CB hyperactivity is currently in its beginning and this review will open doors for future explorations. PMID:25389406

  15. Cellular properties and chemosensory responses of the human carotid body

    PubMed Central

    Ortega-Sáenz, Patricia; Pardal, Ricardo; Levitsky, Konstantin; Villadiego, Javier; Muñoz-Manchado, Ana Belén; Durán, Rocío; Bonilla-Henao, Victoria; Arias-Mayenco, Ignacio; Sobrino, Verónica; Ordóñez, Antonio; Oliver, María; Toledo-Aral, Juan José; López-Barneo, José

    2013-01-01

    The carotid body (CB) is the major peripheral arterial chemoreceptor in mammals that mediates the acute hyperventilatory response to hypoxia. The CB grows in response to sustained hypoxia and also participates in acclimatisation to chronic hypoxaemia. Knowledge of CB physiology at the cellular level has increased considerably in recent times thanks to studies performed on lower mammals, and rodents in particular. However, the functional characteristics of human CB cells remain practically unknown. Herein, we use tissue slices or enzymatically dispersed cells to determine the characteristics of human CB cells. The adult human CB parenchyma contains clusters of chemosensitive glomus (type I) and sustentacular (type II) cells as well as nestin-positive progenitor cells. This organ also expresses high levels of the dopaminotrophic glial cell line-derived neurotrophic factor (GDNF). We found that GDNF production and the number of progenitor and glomus cells were preserved in the CBs of human subjects of advanced age. Moreover, glomus cells exhibited voltage-dependent Na+, Ca2+ and K+ currents that were qualitatively similar to those reported in lower mammals. These cells responded to hypoxia with an external Ca2+-dependent increase of cytosolic Ca2+ and quantal catecholamine secretion, as reported for other mammalian species. Interestingly, human glomus cells are also responsive to hypoglycaemia and together these two stimuli can potentiate each other's effects. The chemosensory responses of glomus cells are also preserved at an advanced age. These new data on the cellular and molecular physiology of the CB pave the way for future pathophysiological studies involving this organ in humans. PMID:24167224

  16. Carotid artery remodelling in relation to body fat distribution, inflammation and sustained weight loss in obesity.

    PubMed

    Kardassis, D; Schönander, M; Sjöström, L; Karason, K

    2014-05-01

    Obesity is known to be associated with carotid artery remodelling, but less is known about how body fat distribution, inflammation and weight loss may affect this relation. Ultrasonography, dual-energy X-ray absorptiometry and computed tomography were performed to evaluate carotid artery intima-media thickness (IMT), body composition and fat distribution, respectively. Participants were divided into three matched study groups (n = 44 per group): obese patients with sustained weight loss 10 years after bariatric surgery [surgery group, body mass index (BMI) 31.5 kg m(-2)]; obese patients who maintained stable weight during the same time period (obese group, BMI 42.5 kg m(-2)); and normal weight subjects (lean group, BMI 24.4 kg m(-2)). Patients in the surgery group, compared with those in the obese group, had slightly lower common carotid artery (CCA) IMT (0.75 ± 0.18 vs. 0.78 ± 0.17 mm) and common carotid bulb (CCB) IMT (0.92 ± 0.32 vs. 0.97 ± 0.32 mm); however, these differences were not statistically significant. Lean individuals, compared with those in the surgery group, had significantly lower CCA and CCB IMT values (P < 0.001). In forward stepwise multiple regression analyses including all subjects (n = 132), CCA IMT was predicted mainly by visceral adipose tissue, but was also related to blood pressure and levels of triglycerides and high-sensitivity C-reactive protein. Carotid lumen diameter was primarily influenced by lean body mass. Visceral adiposity was the main determinant of premature carotid artery atherosclerosis, possibly through elevated blood pressure, dyslipidaemia and inflammation. Lean body mass predicted carotid artery lumen diameter. Obese patients with long-term sustained weight loss did not have thinner carotid artery walls compared with their weight-stable obese counterparts. © 2013 The Association for the Publication of the Journal of Internal Medicine.

  17. Effects of hypoxia on catecholamine synthesis in rabbit carotid body in vitro

    PubMed Central

    Fidone, S.; Gonzalez, C.; Yoshizaki, K.

    1982-01-01

    1. Unanaesthetized, unrestrained rabbits were exposed for 3 hr in a chamber to either air, hypoxic gas mixtures (10% or 14% O2 in N2) or a hyperoxic gas mixture (50% O2 in N2). The carotid bodies were then removed and incubated for 3 hr in modified Tyrode media equilibrated with 100% O2 and containing either [3H]tyrosine or [3H]DOPA. The contents of [3H]DA and [3H]NA in the tissue were determined as described in the preceding paper. 2. When [3H]DOPA was used as precursor, neither labelled dopamine (DA) or noradrenaline (NA) synthesis was increased in carotid bodies from rabbits exposed to 10% O2 in N2. Following exposure to 10% O2 in N2 and incubation with [3H]tyrosine, however, [3H]DA synthesis was increased by 72% above control (air) values while [3H]NA synthesis was unchanged. Less severe hypoxia, 14% O2 in N2, resulted in a smaller increase in [3H]DA synthesis, i.e. 53% above control value. Again, [3H]NA synthesis was unchanged. Similar experiments with the superior cervical ganglion involving exposure of the animals to either 10% or 14% O2 in N2 did not produce any change in the amounts of [3H]DA or [3H]NA synthesized from [3H]tyrosine when compared to control animals breathing air. 3. Sympathectomy of the carotid body or transection of the carotid sinus nerve 12-15 days prior to hypoxic exposure (10% O2 in N2) did not alter the increase in [3H]DA synthesis compared to normally innervated carotid bodies. 4. Carotid bodies incubated with [3H]tyrosine for 2 hr in an alternating O2/N2 sequence (5 min in media equilibrated with 100% O2 followed by 3 min in media equilibrated with 100% N2) synthesized 37% more [3H]DA than control carotid bodies similarly exposed to an alternating O2/O2 sequence. [3H]NA synthesis was unchanged. However, tissue levels of non-metabolized [3H]tyrosine were reduced by 19% in the carotid bodies exposed to the O2/N2 sequence. 5. Exposure of rabbits for 3 hr to 50% O2 in N2, followed by incubation of their carotid bodies in [3H

  18. [Arterial chemoreceptors: cellular and molecular mechanisms in the adaptative and homeostatic function of the carotid body].

    PubMed

    González, C; Rocher, A; Zapata, P

    The carotid body is a sensory chemoreceptor organ located in the vicinity of the carotid bifurcation. Structurally it is composed of cell clusters formed by chemoreceptor and supporting cells. The sensory nerve endings of the carotid sinus nerve penetrate the clusters to synapse with chemoreceptor cells. The carotid body plays an important role in the control of ventilation during hypoxia, hypercapnia and acidosis. Hypoxia and other natural stimuli are detected by chemoreceptor cells which upon stimulation increase their rate of release of neurotransmitters. Neurotransmitters in turn increase the action potential frequency in the carotid sinus nerve which via its central projections to the brainstem activates ventilation. This review is devoted to the cellular aspects of the function of this chemoreceptor organ. From a brief description of the complex structure of the carotid body, we go to present a summary of the main prevailing theories concerning the transduction mechanisms for hypoxic and acidic/hypercapnic stimuli, with special emphasis on the electrical properties of cultured chemoreceptors cells. A special attention is provided to the possible significance of reactive oxygen species as mediators of the hypoxic transduction cascade. The neurotransmission between chemoreceptor cells and the sensory nerve endings is also covered in certain detail. After a brief historical presentation of the theories of communication between these two structures, we examine, following the classical criteria of neurotransmission, the functional significance of acetylcholine, dopamine, substance P and other neurotransmitters known to be present in chemoreceptor cells.

  19. New predictors of complications in carotid body tumor resection.

    PubMed

    Kim, Gloria Y; Lawrence, Peter F; Moridzadeh, Rameen S; Zimmerman, Kate; Munoz, Alberto; Luna-Ortiz, Kuauhyama; Oderich, Gustavo S; de Francisco, Juan; Ospina, Jorge; Huertas, Santiago; de Souza, Leonardo R; Bower, Thomas C; Farley, Steven; Gelabert, Hugh A; Kret, Marcus R; Harris, E John; De Caridi, Giovanni; Spinelli, Francesco; Smeds, Matthew R; Liapis, Christos D; Kakisis, John; Papapetrou, Anastasios P; Debus, Eike S; Behrendt, Christian-A; Kleinspehn, Edgar; Horton, Joshua D; Mussa, Firas F; Cheng, Stephen W K; Morasch, Mark D; Rasheed, Khurram; Bennett, Matthew E; Bismuth, Jean; Lumsden, Alan B; Abularrage, Christopher J; Farber, Alik

    2017-06-01

    This study examined the relationship between two new variables, tumor distance to base of skull (DTBOS) and tumor volume, with complications of carotid body tumor (CBT) resection, including bleeding and cranial nerve injury. Patients who underwent CBT resection between 2004 and 2014 were studied using a standardized, multi-institutional database. Demographic, perioperative, and outcomes data were collected. CBT measurements were determined from computed tomography, magnetic resonance imaging, and ultrasound examination. There were 356 CBTs resected in 332 patients (mean age, 51 years; 72% female); 32% were classified as Shamblin I, 43% as Shamblin II, and 23% as Shamblin III. The mean DTBOS was 3.3 cm (standard deviation [SD], 2.1; range, 0-10), and the mean tumor volume was 209.7 cm(3) (SD, 266.7; range, 1.1-1642.0 cm(3)). The mean estimated blood loss (EBL) was 257 mL (SD, 426; range, 0-3500 mL). Twenty-four percent of patients had cranial nerve injuries. The most common cranial nerves injured were the hypoglossal (10%), vagus (11%), and superior laryngeal (5%) nerves. Both Shamblin grade and DTBOS were statistically significantly correlated with EBL of surgery and cranial nerve injuries, whereas tumor volume was statistically significantly correlated with EBL. The logistic model for predicting blood loss and cranial nerve injury with all three variables-Shamblin, DTBOS, and volume (R(2) = 0.171, 0.221, respectively)-was superior to a model with Shamblin alone (R(2) = 0.043, 0.091, respectively). After adjusting for Shamblin grade and volume, every 1-cm decrease in DTBOS was associated with 1.8 times increase in risk of >250 mL of blood loss (95% confidence interval, 1.25-2.55) and 1.5 times increased risk of cranial nerve injury (95% confidence interval, 1.19-1.92). This large study of CBTs demonstrates the value of preoperatively determining tumor dimensions and how far the tumor is located from the base of the skull. DTBOS and tumor volume, when used

  20. Carotid body chemosensory responses in mice deficient of TASK channels

    PubMed Central

    Ortega-Sáenz, Patricia; Levitsky, Konstantin L.; Marcos-Almaraz, María T.; Bonilla-Henao, Victoria; Pascual, Alberto

    2010-01-01

    Background K+ channels of the TASK family are believed to participate in sensory transduction by chemoreceptor (glomus) cells of the carotid body (CB). However, studies on the systemic CB-mediated ventilatory response to hypoxia and hypercapnia in TASK1- and/or TASK3-deficient mice have yielded conflicting results. We have characterized the glomus cell phenotype of TASK-null mice and studied the responses of individual cells to hypoxia and other chemical stimuli. CB morphology and glomus cell size were normal in wild-type as well as in TASK1−/− or double TASK1/3−/− mice. Patch-clamped TASK1/3-null glomus cells had significantly higher membrane resistance and less hyperpolarized resting potential than their wild-type counterpart. These electrical parameters were practically normal in TASK1−/− cells. Sensitivity of background currents to changes of extracellular pH was drastically diminished in TASK1/3-null cells. In contrast with these observations, responsiveness to hypoxia or hypercapnia of either TASK1−/− or double TASK1/3−/− cells, as estimated by the amperometric measurement of catecholamine release, was apparently normal. TASK1/3 knockout cells showed an enhanced secretory rate in basal (normoxic) conditions compatible with their increased excitability. Responsiveness to hypoxia of TASK1/3-null cells was maintained after pharmacological blockade of maxi-K+ channels. These data in the TASK-null mouse model indicate that TASK3 channels contribute to the background K+ current in glomus cells and to their sensitivity to external pH. They also suggest that, although TASK1 channels might be dispensable for O2/CO2 sensing in mouse CB cells, TASK3 channels (or TASK1/3 heteromers) could mediate hypoxic depolarization of normal glomus cells. The ability of TASK1/3−/− glomus cells to maintain a powerful response to hypoxia even after blockade of maxi-K+ channels, suggests the existence of multiple sensor and/or effector mechanisms, which could

  1. Chronic hyperoxia alters the expression of neurotrophic factors in the carotid body of neonatal rats.

    PubMed

    Dmitrieff, Elizabeth F; Wilson, Julia T; Dunmire, Kyle B; Bavis, Ryan W

    2011-02-15

    Chronic exposure to hyperoxia alters the postnatal development and innervation of the rat carotid body. We hypothesized that this plasticity is related to changes in the expression of neurotrophic factors or related proteins. Rats were reared in 60% O(2) from 24 to 36h prior to birth until studied at 3d of age (P3). Protein levels for brain-derived neurotrophic factor (BDNF) were significantly reduced (-70%) in the P3 carotid body, while protein levels for its receptor, tyrosine kinase B, and for glial cell line-derived neurotrophic factor (GDNF) were unchanged. Transcript levels in the carotid body were downregulated for the GDNF receptor Ret (-34%) and the neuropeptide Vgf (-67%), upregulated for Cbln1 (+205%), and unchanged for Fgf2; protein levels were not quantified for these genes. Immunohistochemical analysis revealed that Vgf and Cbln1 proteins are expressed within the carotid body glomus cells. These data suggest that BDNF, and perhaps other neurotrophic factors, contribute to abnormal carotid body function following perinatal hyperoxia.

  2. Evidence for a carotid body homolog in the lizard Tupinambis merianae.

    PubMed

    Reichert, Michelle N; Brink, Deidre L; Milsom, William K

    2015-01-15

    The homolog to the mammalian carotid body has not yet been identified in lizards. Observational studies and evolutionary history provide indirect evidence for the existence of a chemoreceptor population at the first major bifurcation of the common carotid artery in lizards, but a chemoreceptive role for this area has not yet been definitively demonstrated. We explored this possibility by measuring changes in cardiorespiratory variables in response to focal arterial injections of the hypoxia mimic sodium cyanide (NaCN) into the carotid artery of 12 unanesthetized specimens of Tupinambis merianae. These injections elicited increases in heart rate (f(H); 101±35% increase) and respiratory rate (f(R); 620±119% increase), but not mean arterial blood pressure (MAP). These responses were eliminated by vagal denervation. Similar responses were elicited by injections of the neurotransmitters acetylcholine (ACh) and serotonin (5-HT) but not norepinephrine. Heart rate and respiratory rate increases in response to NaCN could be blocked or reduced by antagonists to ACh (atropine) and/or 5-HT (methysergide). Finally, using immunohistochemistry, we demonstrate the presence of putative chemoreceptive cells immunopositive for the cholinergic cell marker vesicular ACh transporter (VAChT) and 5-HT on internal lattice-like structures at the carotid bifurcation. These results provide evidence in lizards for the existence of dispersed chemoreceptor cells at the first carotid bifurcation in the central cardiovascular area that have similar properties to known carotid body homologs, adding to the picture of chemoreceptor evolution in vertebrates.

  3. Carotid baroreceptor influence on forearm vascular resistance during low level lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Thompson, Cynthia A.; Ludwig, David A.; Convertino, Victor A.

    1991-01-01

    The degree of forearm vasoconstriction induced by low levels of lower body negative pressure (LBNP) provides a measure of the responsiveness of the cardiopulmonary baroreflex. The validity of this measurement is based on the assumption that this vasoconstriction response is not influenced by unloading of carotid baroreceptors. To test the hypothesis that arterial baroreceptor unloading does not alter the degree of forearm vascular resistance during low levels of LBNP, 12 subjects were exposed to -15 and -20 mm Hg LBNP with and without additional artificial (+ 10 mm Hg neck pressure) unloading of the carotid baroreceptors. There was no measurable influence of carotid unloading on forearm vascular resistance at either level of LBNP. It is concluded that forearm vascular resistance measured during cardiopulmonary baroreceptor unloading is unaffected by carotid baroreceptor unloading within the magnitude encountered during low levels of LBNP.

  4. Carotid body overactivity induces respiratory neurone channelopathy contributing to neurogenic hypertension.

    PubMed

    Moraes, Davi J A; Machado, Benedito H; Paton, Julian F R

    2015-07-15

    Why sympathetic activity rises in neurogenic hypertension remains unknown. It has been postulated that changes in the electrical excitability of medullary pre-sympathetic neurones are the main causal mechanism for the development of sympathetic overactivity in experimental hypertension. Here we review recent data suggesting that enhanced sympathetic activity in neurogenic hypertension is, at least in part, dependent on alterations in the electrical excitability of medullary respiratory neurones and their central modulation of sympatho-excitatory networks. We also present results showing a critical role for carotid body tonicity in the aetiology of enhanced central respiratory modulation of sympathetic activity in neurogenic hypertension. We propose a novel hypothesis of respiratory neurone channelopathy induced by carotid body overactivity in neurogenic hypertension that may contribute to sympathetic excess. Moreover, our data support the notion of targeting the carotid body as a potential novel therapeutic approach for reducing sympathetic vasomotor tone in neurogenic hypertension.

  5. Long-term regulation of carotid body function: acclimatization and adaptation--invited article.

    PubMed

    Prabhakar, N R; Peng, Y-J; Kumar, G K; Nanduri, J; Di Giulio, C; Lahiri, Sukhamay

    2009-01-01

    Physiological responses to hypoxia either continuous (CH) or intermittent (IH) depend on the O(2)-sensing ability of the peripheral arterial chemoreceptors, especially the carotid bodies, and the ensuing reflexes play important roles in maintaining homeostasis. The purpose of this article is to summarize the effects of CH and IH on carotid body function and the underlying mechanisms. CH increases baseline carotid body activity and sensitizes the response to acute hypoxia. These effects are associated with hyperplasia of glomus cells and neovascularization. Enhanced hypoxic sensitivity is due to alterations in ion current densities as well as changes in neurotransmitter dynamics and recruitment of additional neuromodulators (endothelin-1, ET-1) in glomus cells. Morphological alterations are in part due to up-regulation of growth factors (e.g. VEGF). Hypoxia-inducible factor-1 (HIF-1), a transcriptional activator might underlie the remodeling of carotid body structure and function by CH. Chronic IH, on the other hand, is associated with recurrent apneas in adults and premature infants. Two major effects of chronic IH on the adult carotid body are sensitization of the hypoxic sensory response and long-lasting increase in baseline activity i.e., sensory long-term facilitation (LTF) which involve reactive oxygen species (ROS) and HIF-1. In neonates, chronic IH leads to sensitization of the hypoxic response but does not induce sensory LTF. Chronic IH-induced sensitization of the carotid body response to hypoxia increases the likelihood of unstable breathing perpetuating in more number of apneas, whereas sensory LTF may contribute to increased sympathetic tone and systemic hypertension associated with recurrent apneas.

  6. Long-Term Regulation of Carotid Body Function: Acclimatization and Adaptation – Invited Article

    PubMed Central

    Prabhakar, N.R.; Peng, Y.-J.; Kumar, G.K.; Di Giulio, C.; Lahiri, Sukhamay

    2014-01-01

    Physiological responses to hypoxia either continuous (CH) or intermittent (IH) depend on the O2-sensing ability of the peripheral arterial chemoreceptors, especially the carotid bodies, and the ensuing reflexes play important roles in maintaining homeostasis. The purpose of this article is to summarize the effects of CH and IH on carotid body function and the underlying mechanisms. CH increases baseline carotid body activity and sensitizes the response to acute hypoxia. These effects are associated with hyperplasia of glomus cells and neovascularization. Enhanced hypoxic sensitivity is due to alterations in ion current densities as well as changes in neurotransmitter dynamics and recruitment of additional neuromodulators (endothelin-1, ET-1) in glomus cells. Morphological alterations are in part due to up-regulation of growth factors (e.g. VEGF). Hypoxia-inducible factor-1 (HIF-1), a transcriptional activator might underlie the remodeling of carotid body structure and function by CH. Chronic IH, on the other hand, is associated with recurrent apneas in adults and premature infants. Two major effects of chronic IH on the adult carotid body are sensitization of the hypoxic sensory response and long-lasting increase in baseline activity i.e., sensory long-term facilitation (LTF) which involve reactive oxygen species (ROS) and HIF-1. In neonates, chronic IH leads to sensitization of the hypoxic response but does not induce sensory LTF. Chronic IH-induced sensitization of the carotid body response to hypoxia increases the likelihood of unstable breathing perpetuating in more number of apneas, whereas sensory LTF may contribute to increased sympathetic tone and systemic hypertension associated with recurrent apneas. PMID:19536494

  7. Carotid body chemoreception: the importance of CO2-HCO3- and carbonic anhydrase. (review).

    PubMed

    Iturriaga, R

    1993-01-01

    The current hypotheses of carotid body (CB) chemoreception regard the glomus cells as the initial site of stimulus transduction. The consensus is that the transduction of chemical stimulus is coupled with the release of transmitter(s) from the glomus cells, which in turn generates action potentials in the afferent nerve terminals. Carbonic anhydrase (CA) is present in the glomus cells of the CB. Inhibition of CA activity in the CB in situ reduces the carotid chemosensory responses to CO2 and to O2, suggesting a common mechanism of chemosensing for both stimuli. However, CA inhibitors also block the red blood cell enzyme. Thus, the CO2 hydration reaction does not come to completion within the transit time of the blood from the lung to the CB. A steady-state reaction is not reached until later and so the PCO2 and pH levels in arterial blood samples are not the same as those sensed by the CB. Experiments in vitro using cat CB perfused and superfused with cell-free solutions, which had been pre-equilibrated with respiratory gases, strongly support the proposition that the CA activity in CB cells is essential for the speed and amplitude of the initial response to CO2 and for its subsequent adaptation. The immediate response to hypoxia also is delayed, but the late steady-state was less dependent on CA activity. In the nominal absence of CO2-HCO3- from the perfusate, hypoxic chemoreception persisted and its magnitude is not affected by CA inhibition, except for a delay which may be due to the initial alkaline pH of the glomus cells. Recent experiments performed in isolated glomus cells and in the whole CB show that hypoxia does not modify significantly the intracellular pH. By its simple catalytic function, CA can speed up the approach of the CO2 hydration reaction to equilibrium. However, CA may also contribute in the steady-state to the regulation of pHi by providing a continuous supply of H+ and HCO3-. Furthermore, CA performs a facilitatory role in the physiological

  8. Iatrogenic central retinal artery occlusion after carotid body tumor embolization and excision.

    PubMed

    Rangel, Carlos M; Jaramillo, Sergio; Varón, Clara L; Prada, Angélica M

    2017-01-01

    Objective: To report a case of iatrogenic central retinal artery occlusion after embolization and surgical resection of carotid body paraganglioma. Methods: Case report Results: One adult female patient presented with persistent unilateral visual loss after embolization with Embosphere(®) and Contour(®) microparticles of carotid body tumor. Fluorescein angiography revealed intraluminal microspheres in the central retinal artery ramifications. OCT revealed intraretinal spherical, hyporeflective particles with posterior shadowing. Conclusions: Central retinal artery occlusion should be assessed as a possible complication after surgical repair of head and neck paragangliomas.

  9. Iatrogenic central retinal artery occlusion after carotid body tumor embolization and excision

    PubMed Central

    Rangel, Carlos M.; Jaramillo, Sergio; Varón, Clara L.; Prada, Angélica M.

    2017-01-01

    Objective: To report a case of iatrogenic central retinal artery occlusion after embolization and surgical resection of carotid body paraganglioma. Methods: Case report Results: One adult female patient presented with persistent unilateral visual loss after embolization with Embosphere® and Contour® microparticles of carotid body tumor. Fluorescein angiography revealed intraluminal microspheres in the central retinal artery ramifications. OCT revealed intraretinal spherical, hyporeflective particles with posterior shadowing. Conclusions: Central retinal artery occlusion should be assessed as a possible complication after surgical repair of head and neck paragangliomas. PMID:28401029

  10. Separation of carotid body chemoreceptor responses to O2 and CO2 by oligomycin and by antimycin A.

    PubMed

    Mulligan, E; Lahiri, S

    1982-03-01

    The cat carotid chemoreceptor O2 and CO2 responses can be separated by oligomycin and by antimycin A. Both of these agents greatly diminish or abolish the chemoreceptor O2 response but not the nicotine or CO2 responses. After either oligomycin or antimycin, the responses to increases and decreases in arterial CO2 partial pressure (PaCO2) consisted of increases and decreases in activity characterized respectively by exaggerated overshoots and undershoots. These were eliminated by the carbonic anhydrase inhibitor, acetazolamide, suggesting that they resulted from changes in carotid body tissue pH. The steady-state PaCO2 response remaining after oligomycin was no longer dependent on arterial O2 partial pressure (PaO2). All effects of antimycin were readily reversible in about 20 min. The separation of the responses to O2 and CO2 indicates that there may be at least partially separate pathways of chemoreception for these two stimuli. The similarity of the oligomycin and antimycin results supports the metabolic hypothesis of chemoreception.

  11. Effect of CO on VO2 of carotid body and chemoreception with and without Ca2+.

    PubMed

    Lahiri, S; Buerk, D G; Osanai, S; Mokashi, A; Chugh, D K

    1997-09-10

    This study was done using high PCO (> 500 Torr at PO2 of 120 Torr) in the carotid body perfusate in vitro, and recording simultaneously the activity of the whole carotid sinus nerve (CSN) and VO2 of the carotid body. In the cascade of excitation of CSN by high PCO in the dark [light eliminated the excitation; S. Lahiri, News Physiol. Sci. 9 (1992) 161-165], Ca2+ effects occur at the level of neurosecretion after the level of oxygen consumption, according to the following scheme: CO-hypoxia-->VO2 decrease-->K+ conductance decrease-->cell depolarization-->cytosolic Ca2+ rise-->neurosecretion-->neural discharge. Thus, a part of the hypothesis was that [Ca2+] decrease, being a downstream event, may not affect VO2 of the carotid body. Also, to determine to what extent the intracellular calcium stores contribute to cystolic [Ca2+] and chemosensory discharge with high PCO, we tested the effect of interruption of perfusate flow with medium nominally free of [Ca2+] on CSN excitation and VO2 of the carotid body with and without high PCO. High PCO in the dark decreased carotid body VO2, independent of [Ca2+]o. CSN excitation was always enhanced by high PCO, and its sensitivity to perfusate flow interruption. Also, nominally Ca(2+)-free solution increased the latency and decreased the rate of rise and peak activity of CSN during interruption of perfusate flow, but CO augmented the responses. This reversal effect by CO suggests that Ca2+ is released from intracellular stores, because CO has no other way to excite the chemoreceptors than by acting on the intracellular stores.

  12. Big cat, small cat: reconstructing body size evolution in living and extinct Felidae.

    PubMed

    Cuff, A R; Randau, M; Head, J; Hutchinson, J R; Pierce, S E; Goswami, A

    2015-08-01

    The evolution of body mass is a fundamental topic in evolutionary biology, because it is closely linked to manifold life history and ecological traits and is readily estimable for many extinct taxa. In this study, we examine patterns of body mass evolution in Felidae (Placentalia, Carnivora) to assess the effects of phylogeny, mode of evolution, and the relationship between body mass and prey choice in this charismatic mammalian clade. Our data set includes 39 extant and 26 extinct taxa, with published body mass data supplemented by estimates based on condylobasal length. These data were run through 'SURFACE' and 'bayou' to test for patterns of body mass evolution and convergence between taxa. Body masses of felids are significantly different among prey choice groupings (small, mixed and large). We find that body mass evolution in cats is strongly influenced by phylogeny, but different patterns emerged depending on inclusion of extinct taxa and assumptions about branch lengths. A single Ornstein-Uhlenbeck optimum best explains the distribution of body masses when first-occurrence data were used for the fossil taxa. However, when mean occurrence dates or last known occurrence dates were used, two selective optima for felid body mass were recovered in most analyses: a small optimum around 5 kg and a large one around 100 kg. Across living and extinct cats, we infer repeated evolutionary convergences towards both of these optima, but, likely due to biased extinction of large taxa, our results shift to supporting a Brownian motion model when only extant taxa are included in analyses. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

  13. Sleep-mediated heart rate variability after bilateral carotid body tumor resection.

    PubMed

    Niemeijer, Nicolasine D; Corssmit, Eleonora P M; Reijntjes, Robert H A M; Lammers, Gert Jan; van Dijk, J Gert; Thijs, Roland D

    2015-04-01

    The carotid bodies are thought to play an important role in sleep-dependent autonomic changes. Patients who underwent resection of bilateral carotid body tumors have chronically attenuated baroreflex sensitivity. These subjects provide a unique opportunity to investigate the role of the baroreflex during sleep. One-night ambulatory polysomnography (PSG) recording. Participants' homes. Nine patients with bilateral carotid body tumor resection (bCBR) (four women, mean age 50.4 ± 7.2 years) and nine controls matched for age, gender, and body mass index. N/A. Sleep parameters were obtained from PSG. Heart rate (HR) and its variability were calculated using 30-s epochs. In bCBR patients, HR was slightly but not significantly increased during wake and all sleep stages. The effect of sleep on HR was similar for patients and controls. Low frequency (LF) power of the heart rate variability spectrum was significantly lower in bCBR patients in active wakefulness, sleep stage 1 and REM sleep. No differences were found between patients and controls for high frequency (HF) power and the LF/HF ratio. Bilateral carotid body tumor resection (bCBR) is associated with decreased low frequency power during sleep, suggesting impaired baroreflex function. Despite this, sleep-related heart rate changes were similar between bCBR patients and controls. These findings suggest that the effects of sleep on heart rate are predominantly generated through central, non-baroreflex mediated pathways. © 2015 Associated Professional Sleep Societies, LLC.

  14. Towards the Sensory Nature of the Carotid Body: Hering, De Castro and Heymans†

    PubMed Central

    de Castro, Fernando

    2009-01-01

    The carotid body or glomus caroticum is a chemosensory organ bilaterally located between the external and internal carotid arteries. Although known by anatomists since the report included by Von Haller and Taube in the mid XVIII century, its detailed study started the first quarter of the XX. The Austro-German physiologist Heinrich E. Hering studied the cardio-respiratory reflexes searched for the anatomical basis of this reflex in the carotid sinus, while the Ghent School leaded by the physio-pharmacologists Jean-François Heymans and his son Corneille focussed in the cardio-aortic reflexogenic region. In 1925, Fernando De Castro, one of the youngest and more brilliant disciples of Santiago Ramón y Cajal at the Laboratorio de Investigaciones Biológicas (Madrid, Spain), profited from some original novelties in histological procedures to study the fine structure and innervation of the carotid body. De Castro unravelled them in a series of scientific papers published between 1926 and 1929, which became the basis to consider the carotid body as a sensory receptor (or chemoreceptor) to detect the chemical changes in the composition of the blood. Indeed, this was the first description of arterial chemoreceptors. Impressed by the novelty and implications of the work of De Castro, Corneille Heymans invited the Spanish neurologist to visit Ghent on two occasions (1929 and 1932), where both performed experiences together. Shortly after, Heymans visited De Castro at the Instituto Cajal (Madrid). From 1932 to 1933, Corneille Heymans focused all his attention on the carotid body his physiological demonstration of De Castro's hypothesis regarding chemoreceptors was awarded with the Nobel Prize in Physiology or Medicine in 1938, just when Spain was immersed in its catastrophic Civil War. PMID:20057927

  15. Towards the sensory nature of the carotid body: hering, de castro and heymansdagger.

    PubMed

    de Castro, Fernando

    2009-01-01

    The carotid body or glomus caroticum is a chemosensory organ bilaterally located between the external and internal carotid arteries. Although known by anatomists since the report included by Von Haller and Taube in the mid XVIII century, its detailed study started the first quarter of the XX. The Austro-German physiologist Heinrich E. Hering studied the cardio-respiratory reflexes searched for the anatomical basis of this reflex in the carotid sinus, while the Ghent School leaded by the physio-pharmacologists Jean-François Heymans and his son Corneille focussed in the cardio-aortic reflexogenic region. In 1925, Fernando De Castro, one of the youngest and more brilliant disciples of Santiago Ramón y Cajal at the Laboratorio de Investigaciones Biológicas (Madrid, Spain), profited from some original novelties in histological procedures to study the fine structure and innervation of the carotid body. De Castro unravelled them in a series of scientific papers published between 1926 and 1929, which became the basis to consider the carotid body as a sensory receptor (or chemoreceptor) to detect the chemical changes in the composition of the blood. Indeed, this was the first description of arterial chemoreceptors. Impressed by the novelty and implications of the work of De Castro, Corneille Heymans invited the Spanish neurologist to visit Ghent on two occasions (1929 and 1932), where both performed experiences together. Shortly after, Heymans visited De Castro at the Instituto Cajal (Madrid). From 1932 to 1933, Corneille Heymans focused all his attention on the carotid body his physiological demonstration of De Castro's hypothesis regarding chemoreceptors was awarded with the Nobel Prize in Physiology or Medicine in 1938, just when Spain was immersed in its catastrophic Civil War.

  16. Antioxidant prevention of Heinz body formation and oxidative injury in cats.

    PubMed

    Hill, A S; O'Neill, S; Rogers, Q R; Christopher, M M

    2001-03-01

    To determine the effectiveness of 3 antioxidants in preventing Heinz body anemia in cats. Prospective study. 44 specific-pathogen-free healthy cats. Cats were housed individually, divided randomly into 4 groups, and given the following orally every 12 hours: empty gelcaps (control cats), N-acetylcysteine (NAC, 100 mg/kg of body weight), vitamin E (d,l-alpha-tocopherol; 400 IU), or ascorbate (250 mg). After 2 weeks, Heinz bodies were induced by dietary onion powder (OP; 1% or 3% of dry matter) or propylene glycol (PG, 8% wt/vol in drinking water) for an additional 3 weeks. Intake of treated water or food was recorded daily. Body weight, PCV, Heinz body and reticulocyte percentages, reduced glutathione concentration, and total antioxidant status were measured twice weekly in all cats. Heinz body percentage and degree of anemia did not differ significantly among cats receiving antioxidants and control cats except in cats that ingested water containing PG, in which antioxidant supplementation was associated with a decrease in water intake. Of cats that were fed a diet that contained OP, cats that received NAC had significantly higher reduced glutathione concentrations, compared with other cats in the experiment. Total antioxidant status did not consistently correlate with antioxidant supplementation or type of oxidant administered (ie, OP or PG). Although the effect of antioxidant supplementation on Heinz body anemia in cats was minimal, antioxidants may have subclinical biochemical effects such as GSH sparing that may be important against milder forms of oxidative stress.

  17. Sleep-Mediated Heart Rate Variability after Bilateral Carotid Body Tumor Resection

    PubMed Central

    Niemeijer, Nicolasine D.; Corssmit, Eleonora P.M.; Reijntjes, Robert H.A.M.; Lammers, Gert Jan; van Dijk, J. Gert; Thijs, Roland D.

    2015-01-01

    Study Objectives: The carotid bodies are thought to play an important role in sleep-dependent autonomic changes. Patients who underwent resection of bilateral carotid body tumors have chronically attenuated baroreflex sensitivity. These subjects provide a unique opportunity to investigate the role of the baroreflex during sleep. Design: One-night ambulatory polysomnography (PSG) recording. Setting: Participants' homes. Participants: Nine patients with bilateral carotid body tumor resection (bCBR) (four women, mean age 50.4 ± 7.2 years) and nine controls matched for age, gender, and body mass index. Interventions: N/A. Measurements: Sleep parameters were obtained from PSG. Heart rate (HR) and its variability were calculated using 30-s epochs. Results: In bCBR patients, HR was slightly but not significantly increased during wake and all sleep stages. The effect of sleep on HR was similar for patients and controls. Low frequency (LF) power of the heart rate variability spectrum was significantly lower in bCBR patients in active wakefulness, sleep stage 1 and REM sleep. No differences were found between patients and controls for high frequency (HF) power and the LF/HF ratio. Conclusions: Bilateral carotid body tumor resection (bCBR) is associated with decreased low frequency power during sleep, suggesting impaired baroreflex function. Despite this, sleep-related heart rate changes were similar between bCBR patients and controls. These findings suggest that the effects of sleep on heart rate are predominantly generated through central, non-baroreflex mediated pathways. Citation: Niemeijer ND, Corssmit EP, Reijntjes RH, Lammers GJ, van Dijk JG, Thijs RD. Sleep-mediated heart rate variability after bilateral carotid body tumor resection. SLEEP 2015;38(4):633–639. PMID:25325476

  18. Rotenone selectively occludes sensitivity to hypoxia in rat carotid body glomus cells

    PubMed Central

    Ortega-Sáenz, Patricia; Pardal, Ricardo; García-Fernández, María; López-Barneo, José

    2003-01-01

    Carotid body glomus cells release transmitters in response to hypoxia due to the increase of excitability resulting from inhibition of O2 -regulated K+ channels. However, the mechanisms involved in the detection of changes of O2 tension are unknown. We have studied the interaction between glomus cell O2 sensitivity and inhibition of the mitochondrial electron transport chain (ETC) in a carotid body thin slice preparation in which catecholamine release from intact single glomus cells can be monitored by amperometry. Inhibition of the mitochondrial ETC at proximal and distal complexes induces external Ca2+-dependent catecholamine secretion. At saturating concentration of the ETC inhibitors, the cellular response to hypoxia is maintained. However, rotenone, a complex I blocker, selectively occludes the responsiveness to hypoxia of glomus cells in a dose-dependent manner. The effect of rotenone is mimicked by 1-methyl-4-phenylpyridinium ion (MPP+), an agent that binds to the same site as rotenone, but not by complex I inhibitors acting on different sites. In addition, the effect of rotenone is not prevented by incubation of the cells with succinate, a substrate of complex II. These data strongly suggest that sensitivity to hypoxia of carotid body glomus cells is not linked in a simple way to mitochondrial electron flow and that a rotenone (and MPP+)-sensitive molecule critically participates in acute oxygen sensing in the carotid body. PMID:12626666

  19. Coexpression of Galanin and Nestin in the Chemoreceptor Cells of the Human Carotid Body.

    PubMed

    Mazzatenta, Andrea; Marconi, Guya D; Macchi, Veronica; Porzionato, Andrea; Cataldi, Amelia; Di Giulio, Camillo; Pokorski, Mieczyslaw

    2016-01-01

    The carotid body is a highly specialized chemoreceptive organ of neural crest origin whose role is to detect changes in arterial oxygen content. The sensory units are the chemoreceptor cells, which are neuronal-like cells, surrounded by sustentacular or glial-like cells. It is suggested that the carotid body contains self-renewing multipotent stem cells, which are putatively represented by glial-like sustentacular cells. The mechanisms of renewal of neuronal-like cells are unclear. Recently, we have demonstrated the expression of galanin, a peptide promoting neurogenesis, in chemoreceptor cells in the human CB. Thus, in the present study we seek to determine whether galanin expression in chemoreceptor cells could be matched with that of nestin, a peptide that is a marker of multipotent neural stem cells, or rather with the glial fibrillary acidic protein (GFAP), a marker for glial cells. The latter would underscore the pluasibly essential role of sustentacular cells in the self-renewal capability of chemorecetors. We found that galanin expression is matched with nestin in chemoreceptor cells of the human carotid body, but not with that of GFAP. Thus, galanin expression in chemoreceptor cells could provide a signal for neurogenesis and chemoreceptor cell differentiation in the carotid body.

  20. Carotid Intima Media Thickness as a Reflection of Generalized Atherosclerosis is Related to Body Mass Index in Ischemic Stroke Patients.

    PubMed

    Singh, Amit Shankar; Atam, Virendra; Patel, Munna Lal; Chaudhary, Shyam Chand; Sawlani, Kamal Kumar; Das, Liza

    2013-03-01

    Carotid artery intima media thickness reflects the ongoing process of atherosclerosis in the body. The pathologic process occurring in the obese patients in the vascular system is atherosclerosis which is an important cause of ischemic stroke. Body mass index is an indirect measure of obesity in general population. The study was to assess the role of carotid artery intima media thickness as a marker of atherosclerosis and its relation with body mass index in ischemic stroke patients. Body mass index of the all stroke patients was calculated by using formula body mass in kilograms divided by the square of height in meters. The patients were classified in four groups of body mass index according to Indian standards. Carotid sonography was done to assess the common carotid artery intima media thickness in millimeters by using high resolution 7.5 MHz sonography technique. The average Carotid intima media thickness in this study was 9.23mm. There was a significant association found between increasing carotid artery intima media thickness and groups of body mass index (P- <0.05) in ischemic stroke patients. Body mass index as an indicator of obesity and carotid intima media thickness both are very important risk factors for ischemic stroke and are associated with each other.

  1. Carotid Ultrasound Imaging

    MedlinePlus

    ... Index A-Z Ultrasound - Carotid Carotid ultrasound uses sound waves to produce pictures of the carotid arteries ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  2. The discovery of sensory nature of the carotid bodies--invited article.

    PubMed

    De Castro, F

    2009-01-01

    Although the carotid body (or glomus caroticum) was a structure familiar to anatomists in the XVIIIth century, it was not until the beginning of the XXth century that its role was revealed. It was then that the German physiologist Heinrich Hering described the respiratory reflex and he began to study the anatomical basis of this reflex focusing on the carotid region, and the carotid sinus in particular. At this time, the physiologists and pharmacologists associated with Jean-François Heymans and his son (Corneille) in Ghent (Belgium) adopted a different approach to resolve this issue, and they centred their efforts on the cardio-aortic reflexogenic region. However, at the Laboratorio de Investigaciones Biológicas (Madrid, Spain), one of the youngest and more brilliant disciples of Santiago Ramón y Cajal, Fernando De Castro, took advantage of certain technical advances to study the fine structure of the carotid body (De Castro, 1925). In successive papers (1926, 1928, 1929), De Castro unravelled most of the histological secrets of this small structure and described the exact localisation of the "chemoreceptors" within the glomus. Indeed, his was the first description of cells specifically devoted to detect changes in the chemical composition of blood. Heymans was deeply interested in the work of De Castro, and he extended two invitations to the Spanish neurologist to visit (1929 and 1932) so that they could share their experiences. From 1932-1933, Corneille Heymans focused his attention on the carotid body and his physiological demonstration of De Castro's hypothesis regarding chemoreceptors led to him obtaining the Nobel Prize in Physiology or Medicine in 1938, while Spain was immersed in its catastrophic Civil War.

  3. Percutaneous Injection of Lidocaine Within the Carotid Body Area in Carotid Artery Stenting: An 'Old-New' Technique

    SciTech Connect

    Mourikis, Dimitrios; Chatoupis, Konstantinos; Katsenis, Konstantinos; Vlahos, Lampros; Chatziioannou, Achilles

    2008-07-15

    Severe bradycardia is a common untoward effect during balloon angioplasty when performing carotid artery stenting. Therefore atropine injection even before dilatation and the presence of an anesthesiologist are advocated in all patients. In the surgical literature, injection of a local anesthetic agent into the carotid sinus before carotid endarterectomy was performed in an attempt to ameliorate perioperative hemodynamic instability. This study was undertaken to test the hypothesis that percutaneous infiltration of the carotid sinus with local anesthetic immediately before balloon dilatation reduces bradycardia and ameliorates the need for atropine injection or the presence of an anesthesiologist. Infiltration of the carotid sinus with 5 ml of 1% lidocaine, 3 min before dilatation, was performed in 30 consecutive patients. No one exhibited any significant rhythm change that required atropine injection. The anesthesiologist did not face any hemodynamic instability during the carotid artery stenting procedure.

  4. Regulation of common carotid arterial blood flow by nitrergic neurons in the medulla of cats.

    PubMed

    Gong, Chi-Li; Chiu, Yung-Tsung; Lin, Nai-Nu; Cheng, Ching-Chang; Li, Hsing-Tan; Kuo, Jon-Son

    2007-02-05

    Glutamate stimulation of the dorsal facial area, an area located dorsal to the facial nucleus, increases common carotid arterial blood flow. Nitrergic neurons are important in cardiovascular regulatory areas. We investigated whether the nitrergic neurons might be present and play a role in the dorsal facial area to regulate the arterial blood flow. Injections of L-arginine (an NO precursor) and sodium nitroprusside (an NO donor) into the area caused dose-dependent increases in the arterial blood flow. Injection of N(G)-nitro-arginine methyl ester (L-NAME, an NO synthase inhibitor) or methylene blue (a guanylate cyclase inhibitor) decreased the arterial blood flow. Nitrergic neurons and fibers were found in the dorsal facial area by histochemical staining of nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase, a maker of NO synthase. In conclusion, nitrergic neurons are present in the dorsal facial area and appear to release NO tonically in stimulating the area to cause increase in common carotid arterial blood flow.

  5. CT AND MRI FEATURES OF CAROTID BODY PARAGANGLIOMAS IN 16 DOGS.

    PubMed

    Mai, Wilfried; Seiler, Gabriela S; Lindl-Bylicki, Britany J; Zwingenberger, Allison L

    2015-01-01

    Carotid body tumors (paragangliomas) arise from chemoreceptors located at the carotid bifurcation. In imaging studies, this neoplasm may be confused with other neck neoplasms such as thyroid carcinoma. The purpose of this retrospective, cross-sectional study was to describe computed tomographic (CT) and magnetic resonance imaging (MRI) characteristics of confirmed carotid body tumors in a multi-institutional sample of dogs. A total of 16 dogs met inclusion criteria (14 examined using CT and two with MRI). The most common reason for imaging was a palpable cervical mass or respiratory signs (i.e., dyspnea or increased respiratory noises). The most commonly affected breed was Boston terrier (n = 5). Dogs were predominantly male castrated (n = 10) and the median age was 9 years [range 3-14.5]. Most tumors appeared as a large mass centered at the carotid bifurcation, with poor margination in six dogs and discrete margins in ten dogs. Masses were iso- to hypoattenuating to adjacent muscles in CT images and hyperintense to muscles in T1- and T2-weighted MRI. For both CT and MRI, masses typically showed strong and heterogeneous contrast enhancement. There was invasion into the adjacent structures in 9/16 dogs. In six of these nine dogs, the basilar portion of the skull was affected. The external carotid artery was entrapped in seven dogs. There was invasion into the internal jugular vein in three dogs, and into the external jugular, maxillary, and linguo-facial veins in one dog. Imaging characteristics helped explain some clinical presentations such as breathing difficulties, Horner's syndrome, head tilt, or facial nerve paralysis. © 2015 American College of Veterinary Radiology.

  6. Body composition and common carotid artery remodeling in a healthy population.

    PubMed

    Kozakova, Michaela; Palombo, Carlo; Paterni, Marco; Anderwald, Christian-Heinz; Konrad, Thomas; Colgan, Mary-Paula; Flyvbjerg, Allan; Dekker, Jacqueline

    2008-09-01

    An independent association between obesity and preclinical carotid atherosclerosis has been demonstrated, however, the pathophysiological links were not clearly established. Body composition (BC) influences systemic hemodynamics and may participate in the remodeling of common carotid artery (CCA), independently of risk factors. This study evaluated the association between CCA structure and BC in a large population of healthy subjects. This was a cross-sectional study. The study was conducted at 19 European centers. The study included 627 healthy subjects (252 men, age 30-60 yr, body mass index 17-40 kg/m2). CCA luminal diameter and intima-media thickness were measured on digitized ultrasound images. Acoustic properties of CCA wall were evaluated by digital densitometric analysis and described in terms of mean gray level. BC was assessed by electrical bioimpedance. Insulin sensitivity (euglycemic hyperinsulinemic clamp) and plasma adiponectin levels were measured. Associations between CCA structure, age, BC, and metabolic and atherosclerotic risk factors were analyzed by multivariate regression models. Independent factors affecting CCA diameter were fat-free mass and waist girth (standardized r = 0.44 and 0.12; P < 0.01 and < 0.0001; R2 = 0.35); independent correlates of intima-media thickness were age, CCA diameter, systolic blood pressure, and low-density lipoprotein-cholesterol (standardized r = 0.39, 0.25, 0.10, and 0.14; P < 0.005-0.0001; R2 = 0.40). The mean gray level of carotid wall was independently associated with age and waist girth (standardized r = 0.23 and 0.12; P < 0.0001 and = 0.001; R2 = 0.30). Findings of this cross-sectional study suggest that BC modulates CCA diameter, and may induce adaptive changes in carotid wall thickness, independently of metabolic and atherosclerotic factors. Central adiposity modifies the acoustic properties of carotid wall.

  7. Hes1 is required for the development of the superior cervical ganglion of sympathetic trunk and the carotid body.

    PubMed

    Kameda, Yoko; Saitoh, Takayoshi; Nemoto, Noriko; Katoh, Tokio; Iseki, Sachiko

    2012-08-01

    Hes1 gene represses the expression of proneural basic helix-loop-helix (bHLH) factor Mash1, which is essential for the differentiation of the sympathetic ganglia and carotid body glomus cells. The sympathetic ganglia, carotid body, and common carotid artery in Wnt1-Cre/R26R double transgenic mice were intensely labeled by X-gal staining, i.e., the neural crest origin. The deficiency of Hes1 caused severe hypoplasia of the superior cervical ganglion (SCG). At embryonic day (E) 17.5-E18.5, the volume of the SCG in Hes1 null mutants was reduced to 26.4% of the value in wild-type mice. In 4 of 30 cases (13.3%), the common carotid artery derived from the third arch artery was absent in the null mutants, and the carotid body was not formed. When the common carotid artery was retained, the organ grew in the wall of the third arch artery and glomus cell precursors were provided from the SCG in the null mutants as well as in wild-types. However, the volume of carotid body in the null mutants was only 52.5% of the value in wild-types at E17.5-E18.5. These results suggest that Hes1 plays a critical role in regulating the development of neural crest derivatives in the mouse cervical region.

  8. Carotid baroreceptor stimulation alters cutaneous vascular conductance during whole-body heating in humans

    PubMed Central

    Keller, David M; Davis, Scott L; Low, David A; Shibasaki, Manabu; Raven, Peter B; Crandall, Craig G

    2006-01-01

    Prior studies investigating carotid baroreflex control of the cutaneous vasculature have yielded mixed findings. However, previously used methodological and analytical techniques may limit the ability to detect carotid baroreflex-mediated changes in cutaneous vascular conductance (CVC). The aim of this study was to test the hypothesis that dynamic carotid baroreceptor stimulation (i.e. 5 s trials) using neck pressure (NP, simulated carotid hypotension) and neck suction (NS, simulated carotid hypertension) will decrease and increase CVC, respectively, during normothermic and whole-body heating conditions in resting humans. Data were obtained from nine subjects (age, 31 ± 2 year). The ratio of forearm skin blood flux (laser-Doppler flowmetry) and arterial blood pressure (Finapres) was used as an index of CVC. Multiple 5 s trials of NP (+40Torr) and NS (−60Torr), as well as breath-hold/airflow control trials, were applied during end-expiratory breath-holds while subjects were normotheric and heat stressed (change in core temperature ∼0.75°C). CVC responses to each NP and NS trial were averaged into 1 s intervals during the following periods: 3 s prestimulus, 5 s during stimulus, and 5 s poststimulus. Peak CVC responses (3 s average) to NP and NS were compared to prestimulus values using paired t test. During normothermia, NP decreased CVC by 0.032 ± 0.007 arbitrary units (a.u.) mmHg−1; (P < 0.05); however, breath-hold/airflow control trials resulted in similar decreases in CVC. NS did not change CVC (Δ = 0.002 ± 0.005 a.u. mmHg−1; P = 0.63). During whole-body heating, NP decreased CVC (by 0.16 ± 0.04 a.u. mmHg−1; (P < 0.05), whereas NS increased CVC by 0.07 ± 0.03 a.u. mmHg−1; (P < 0.05). Furthermore, these changes were greater than, or directionally different from, the breath-hold/airflow control trials. These findings indicate that carotid baroreceptor stimulation elicits dynamic changes in CVC and that these changes are more apparent during whole-body

  9. Trained vs untrained evaluator assessment of body condition score as a predictor of percent body fat in adult cats.

    PubMed

    Shoveller, Anna K; DiGennaro, Joe; Lanman, Cynthia; Spangler, Dawn

    2014-12-01

    Body condition scoring (BCS) provides a readily available technique that can be used by both veterinary professionals and owners to assess the body condition of cats, and diagnose overweight or underweight conditions. The objective of this study was to evaluate a five-point BCS system with half-point delineations using dual-energy x-ray absorptiometry (DXA). Four evaluators (a veterinarian, veterinary technician, trained scorer and untrained scorer) assessed 133 neutered adult cats. For all scorers, BCS score was more strongly correlated with percent body fat than with body weight. Percent body fat increased by approximately 7% within each step increase in BCS. The veterinarian had the strongest correlation coefficient between BCS and percent fat (r = 0.80). Mean body fat in cats classified as being in ideal body condition was 12 and 19%, for 3.0 and 3.5 BCS, respectively. Within BCS category, male cats were significantly heavier in body weight than females within the same assigned BCS category. However, DXA-measured percent body fat did not differ significantly between male and female cats within BCS category, as assigned by the veterinarian (P >0.13). Conversely, when assessed by others, mean percent body fat within BCS category was lower in males than females for cats classified as being overweight (BCS >4.0). The results of this study show that using a BCS system that has been validated within a range of normal weight to moderately overweight cats can help to differentiate between lean cats and cats that may not be excessively overweight, but that still carry a higher proportion of body fat.

  10. Chemoreceptor discharges and cytochrome redox changes of the rat carotid body: Role of heme ligands

    PubMed Central

    Lahiri, Sukhamay; Ehleben, Wilhelm; Acker, Helmut

    1999-01-01

    In superfused in vitro rat carotid body, we recorded chemoreceptor discharges and the redox state of cytochromes simultaneously to identify the primary oxygen-sensing protein controlling transmitter release and electrical activity of the carotid sinus nerve. These parameters were tested under the influence of heme ligands such as oxygen, cyanide, 4-(2-aminoethyl)-benzenesulfonyl fluoride, and CO. During stimulation, there was an initial increase in discharge frequency followed by a decline or suppression of activity. Photometric changes lagged and were maintained as nerve activity decreased. Reducing mitochondrial cytochromes by cyanide or prolonged severe hypoxia, suppressed the chemoreceptor discharge. 4-(2-Aminoethyl)-benzenesulfonyl fluoride, a specific inhibitor of the phagocytic cytochrome b558, also silenced the chemoreceptors after an initial excitation. CO increased the chemoreceptor discharge under normoxia, an effect inhibited by light, when the cytochromes were not reduced. When the discharges were depressed by severe hypoxia, exposure to light excited the chemoreceptors and the cytochromes were reduced. The rapidity of the chemosensory responses to light and lack of effect on dopamine release from type I cells led us to hypothesize that carotid body type I cells and the apposed nerve endings use different mechanisms for oxygen sensing: the nerve endings generate action potentials in association with membrane heme proteins whereas cytosolic heme proteins signal the redox state, releasing modulators or transmitters from type I cells. PMID:10430959

  11. Imaging findings of malignant bilateral carotid body tumors: A case report and review of the literature

    PubMed Central

    LV, HAN; CHEN, XIAOHONG; ZHOU, SHUAI; CUI, SUPING; BAI, YUNLONG; WANG, ZHENCHANG

    2016-01-01

    Carotid body tumors (CBTs) are a rare type of extra-adrenal paraganglioma, which originate from the carotid body. A 29-year-old woman was admitted to the Department of Head and Neck Surgery, Beijing Tongren Hospital (Capital Medical University, Beijing, China) with hoarseness of the throat, which had progressively worsened over seven months. The patient had a family history of CBTs. Computed tomography and ultrasound imaging revealed multiple well-enhanced masses located at the bilateral carotid bifurcation and in the left parapharyngeal space. Surgery and pathological examination confirmed that the patient had developed regional lymph node metastasis. Significantly enhanced multiple pulmonary and hepatic lesions indicated that the patient had also developed distal metastasis. A genetic analysis performed on the family members of the patient revealed that the family carried a mutated succinate dehydrogenase D gene. In the present study, a systemic review of the literature indicated that extra vigilance is required in familial forms of CBT, in order to increase the standard of treatment for CBT patients. PMID:27073498

  12. Evaluation of plasma islet amyloid polypeptide and serum glucose and insulin concentrations in nondiabetic cats classified by body condition score and in cats with naturally occurring diabetes mellitus.

    PubMed

    Henson, Michael S; Hegstad-Davies, Rebecca L; Wang, Qi; Hardy, Robert M; Armstrong, P Jane; Jordan, Kathryn; Johnson, Kenneth H; O'Brien, Timothy D

    2011-08-01

    To evaluate and compare circulating concentrations of islet amyloid polypeptide (IAPP), insulin, and glucose in nondiabetic cats classified by body condition score (BCS) and in cats with naturally occurring diabetes mellitus. 109 (82 nondiabetic, 21 nonketoacidotic diabetic, and 6 ketoacidotic diabetic) cats. Cats were examined and BCSs were assessed on a scale of 1 to 9. After food was withheld for 12 hours, blood was collected and plasma concentrations of IAPP and serum concentrations of insulin and glucose were measured. Differences in these values were evaluated among nondiabetic cats grouped according to BCS and in diabetic cats grouped as ketoacidotic or nonketoacidotic on the basis of clinicopathologic findings. Correlations were determined among variables. In nondiabetic cats, BCS was significantly and positively correlated with circulating IAPP and insulin concentrations. Mean plasma IAPP concentrations were significantly different between cats with BCSs of 5 and 7, and mean serum insulin concentrations were significantly different between cats with BCSs of 5 and 8. Serum glucose concentrations were not significantly different among nondiabetic cats. Mean IAPP concentrations were similar between nonketoacidotic diabetic cats and nondiabetic cats with BCSs of 8 or 9. Mean IAPP concentrations were significantly reduced in ketoacidotic diabetic cats, compared with those of nondiabetic cats with BCSs of 6 through 8 and of nonketoacidotic diabetic cats. Results indicated that increased BCS (a measure of obesity) is associated with increased circulating concentrations of IAPP and insulin in nondiabetic cats.

  13. Deoxyglucose mapping in the cat visual cortex following carotid artery injection and cortical flat-mounting.

    PubMed

    Freeman, B; Löwel, S; Singer, W

    1987-06-01

    Two techniques are described for improving the efficiency of the deoxyglucose metabolic mapping procedure for studies on the cat visual cortex. The first technique involves the bilateral cannulation of the lingual arteries and the symmetrical injection of 2-deoxy-D-[U-14C]glucose in amounts significantly smaller than required with systemic intravenous administration. The second technique is carried out at the end of the stimulation period and involves unfolding the grey matter of the occipital region of the unfixed cortex by blunt dissection (defibrillation) and cutting of the white matter to make a cortical flat-mount: this permits the preparation of large sections parallel to the cortical laminae and thus the interpretation of deoxyglucose uptake patterns in any one lamina over a large area of the visual cortex. The experiments are relatively cheap and the time required to flat-mount the cortices does not seem to produce any significant decrease in spatial resolution of the autoradiograms. In appropriate experiments (published elsewhere) the techniques allow a comparative analysis of the deoxyglucose patterns between hemispheres receiving different visual stimulation.

  14. Enhanced carotid body chemosensory activity and the cardiovascular alterations induced by intermittent hypoxia

    PubMed Central

    Iturriaga, Rodrigo; Andrade, David C.; Del Rio, Rodrigo

    2014-01-01

    The carotid body (CB) plays a main role in the maintenance of the oxygen homeostasis. The hypoxic stimulation of the CB increases the chemosensory discharge, which in turn elicits reflex sympathetic, cardiovascular, and ventilatory adjustments. An exacerbate carotid chemosensory activity has been associated with human sympathetic-mediated diseases such as hypertension, insulin resistance, heart failure, and obstructive sleep apnea (OSA). Indeed, the CB chemosensory discharge becomes tonically hypereactive in experimental models of OSA and heart failure. Chronic intermittent hypoxia (CIH), a main feature of OSA, enhances CB chemosensory baseline discharges in normoxia and in response to hypoxia, inducing sympathetic overactivity and hypertension. Oxidative stress, increased levels of ET-1, Angiotensin II and pro-inflammatory cytokines, along with a reduced production of NO in the CB, have been associated with the enhanced carotid chemosensory activity. In this review, we will discuss new evidence supporting a main role for the CB chemoreceptor in the autonomic and cardiorespiratory alterations induced by intermittent hypoxia, as well as the molecular mechanisms involved in the CB chemosensory potentiation. PMID:25520668

  15. Clinical characteristics and remedies in 45 Iranians with carotid body tumors.

    PubMed

    Nazari, Iraj; Aarabi Moghaddam, Fatemeh; Zamani, Mohammad Mahdi; Salimi, Javad

    2012-01-01

    Carotid body tumors (CBTs) are rare, slow-growing tumors that should be considered in evaluating every lateral neck mass. This single center study was performed to define demographic features, clinical characteristics and remedies of Iranian patients with CBT. A retrospective review of prospectively collected data was done on 45 patients with 50 CBTs who have been referred to Sina Hospital, Tehran, Iran, during a 10-year period, were investigated in this study. The demographic characteristics, clinical and pathologic features, imagings, preoperative treatments, surgical approach and complications were analyzed. The study group predominantly consisted of females (82%). Age of diagnosis was 18 to 75 years old. Five patients had bilateral CBT. Family history of CBT was positive in seven patients. Most of CBTs were ≤ 3cm in size. All of the patients presented with a neck mass, mostly without pain (84%). Other symptoms included vertigo 4%, dysphasia 4% and tinnitus 2%. There was no patient with cranial nerve involvement at presentation. The most common imaging helping the diagnosis was color Doppler sonography. Three patients had preoperative embolization. All patients underwent surgery and seven patients had post-operative cranial nerve injury. Nine cases underwent external carotid artery ligation and four ones had external carotid repair. Post operative mortality rate was one patient. This study provides epidemiological data on patients with CBT in Iran, which could be useful for health care workers in prompt diagnosis and appropriate work ups for patient's families in bilateral CBTs.

  16. Fractal analysis of the structural complexity of the connective tissue in human carotid bodies

    PubMed Central

    Guidolin, Diego; Porzionato, Andrea; Tortorella, Cinzia; Macchi, Veronica; De Caro, Raffaele

    2014-01-01

    The carotid body (CB) may undergo different structural changes during perinatal development, aging, or in response to environmental stimuli. In the previous literature, morphometric approaches to evaluate these changes have considered quantitative first order parameters, such as volumes or densities, while changes in spatial disposition and/or complexity of structural components have not yet been considered. In the present study, different strategies for addressing morphological complexity of CB, apart from the overall amount of each tissue component, were evaluated and compared. In particular, we considered the spatial distribution of connective tissue in the carotid bodies of young control subjects, young opiate-related deaths and aged subjects, through analysis of dispersion (Morisita's index), gray level co-occurrence matrix (entropy, angular second moment, variance, correlation), and fractal analysis (fractal dimension, lacunarity). Opiate-related deaths and aged subjects showed a comparable increase in connective tissue with respect to young controls. However, the Morisita's index (p < 0.05), angular second moment (p < 0.05), fractal dimension (p < 0.01), and lacunarity (p < 0.01) permitted to identify significant differences in the disposition of the connective tissue between these two series. A receiver operating characteristic (ROC) curve was also calculated to evaluate the efficiency of each parameter. The fractal dimension and lacunarity, with areas under the ROC curve of 0.9651 (excellent accuracy) and 0.8835 (good accuracy), respectively, showed the highest discriminatory power. They evidenced higher level of structural complexity in the carotid bodies of opiate-related deaths than old controls, due to more complex branching of intralobular connective tissue. Further analyses will have to consider the suitability of these approaches to address other morphological features of the CB, such as different cell populations, vascularization, and innervation

  17. Fractal analysis of the structural complexity of the connective tissue in human carotid bodies.

    PubMed

    Guidolin, Diego; Porzionato, Andrea; Tortorella, Cinzia; Macchi, Veronica; De Caro, Raffaele

    2014-01-01

    The carotid body (CB) may undergo different structural changes during perinatal development, aging, or in response to environmental stimuli. In the previous literature, morphometric approaches to evaluate these changes have considered quantitative first order parameters, such as volumes or densities, while changes in spatial disposition and/or complexity of structural components have not yet been considered. In the present study, different strategies for addressing morphological complexity of CB, apart from the overall amount of each tissue component, were evaluated and compared. In particular, we considered the spatial distribution of connective tissue in the carotid bodies of young control subjects, young opiate-related deaths and aged subjects, through analysis of dispersion (Morisita's index), gray level co-occurrence matrix (entropy, angular second moment, variance, correlation), and fractal analysis (fractal dimension, lacunarity). Opiate-related deaths and aged subjects showed a comparable increase in connective tissue with respect to young controls. However, the Morisita's index (p < 0.05), angular second moment (p < 0.05), fractal dimension (p < 0.01), and lacunarity (p < 0.01) permitted to identify significant differences in the disposition of the connective tissue between these two series. A receiver operating characteristic (ROC) curve was also calculated to evaluate the efficiency of each parameter. The fractal dimension and lacunarity, with areas under the ROC curve of 0.9651 (excellent accuracy) and 0.8835 (good accuracy), respectively, showed the highest discriminatory power. They evidenced higher level of structural complexity in the carotid bodies of opiate-related deaths than old controls, due to more complex branching of intralobular connective tissue. Further analyses will have to consider the suitability of these approaches to address other morphological features of the CB, such as different cell populations, vascularization, and innervation.

  18. Multiple effects of nordihydroguaiaretic acid on ionic currents in rat isolated type I carotid body cells

    PubMed Central

    Hatton, C J; Peers, C

    1997-01-01

    The effects of the lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA) on the ionic currents of rat carotid body type I cells were investigated by use of whole-cell and outside-out patch clamp techniques. NDGA (5–50 μM) produced a concentration-dependent inhibition of whole-cell K+ currents at all activating test potentials (holding potential −70 mV). The time-course of the inhibition was also concentration-dependent and the effects of NDGA were only reversible following brief periods of exposure (<2 min). Another lipoxygenase inhibitor, phenidone (5 μM), was without effect on whole-cell K+ currents in carotid body type I cells. NDGA (5–50 μM) also inhibited whole-cell Ca2+ channel currents (recorded with Ba2+ as charge carrier) in a concentration-dependent manner. Isolation of voltage-gated K+ channels by use of high [Mg2+] (6 mM), low [Ca2+] (0.1 mM) solutions revealed a direct inhibition of the voltage-sensitive component of the whole-cell K+ current by NDGA (50 μM). In excised, outside-out patches NDGA (20–50 μM) increased large conductance, Ca2+ activated K+ channel activity approximately 10 fold, an effect which could be reversed by either tetraethylammonium (10 mM) or charybdotoxin (30 nM). It is concluded that NDGA activates maxi-K+ channels in carotid body type I cells and over the same concentration range inhibits voltage-sensitive K+ and Ca2+ channels. The inhibition of whole cell K+ currents seen is most likely due to a combination of direct inhibition of the voltage-sensitive K+ current and indirect inhibition of maxi-K+ channel activity through blockade of Ca2+ channels. PMID:9384510

  19. Effects of angiotensin II on leptin and downstream leptin signaling in the carotid body during acute intermittent hypoxia.

    PubMed

    Moreau, J M; Messenger, S A; Ciriello, J

    2015-12-03

    Angiotensin II (ANG II) is known to promote leptin production and secretion. Although ANG II type 1 receptors (AT1Rs) and leptin are expressed within the carotid body, it is not known whether AT1R and leptin are co-expressed in the same glomus cells nor if these peptides are affected within the carotid body by intermittent hypoxia (IH). This study was done to investigate whether ANG II modulated leptin signaling in the carotid body during IH. Rats were treated with captopril (Capt) or the AT1R blocker losartan (Los) in the drinking water for 3days prior to being exposed to IH (8h) or normoxia (8h). IH induced increases in plasma ANG II and leptin compared to normoxic controls. Capt treatment abolished the plasma leptin changes to IH, whereas Los treatment had no effect on the IH induced increase in plasma leptin. Additionally, carotid body glomus cells containing both leptin and the long form of the leptin receptor (OB-Rb) were found to co-express AT1R protein, and IH increased the expression of only AT1R protein within the carotid body in both Capt- and non-Capt-treated animals. On the other hand, Los treatment did not modify AT1R protein expression to IH. Additionally, Capt and Los treatment eliminated the elevated carotid body leptin protein expression, and the changes in phosphorylated signal transducer and activator of transcription three protein, the short form of the leptin receptor (OB-R100), suppressor of cytokine signaling 3, and phosphorylated extracellular-signal-regulated kinase 1/2 protein expression induced by IH. However, Capt elevated the expression of OB-Rb protein, whereas Los abolished the changes in OB-Rb protein to IH. These findings, taken together with the previous observation that ANG II modifies carotid body chemosensitivity, suggest that the increased circulating levels of ANG II and leptin induced by IH act at the carotid body to alter leptin signaling within the carotid body which in turn may influence chemoreceptor function.

  20. Radical resection of a Shamblin type III carotid body tumour without cerebro-neurological deficit: Improved technique with preoperative embolization and carotid stenting.

    PubMed

    Ong, H S; Fan, X D; Ji, T

    2014-12-01

    The surgical resection of a large unfavourable Shamblin type III carotid body tumour (CBT) can be very challenging technically, with many potential significant complications. Preoperative embolization aids in shrinking the lesion, reducing intraoperative blood loss, and improving visualization of the surgical field. Preoperative internal carotid artery (ICA) stenting aids in reinforcing the arterial wall, thereby providing a better dissection plane. A woman presented to our institution with a large right-sided CBT. Failure of the preoperative temporary balloon occlusion (TBO) test emphasized the importance of intraoperative preservation of the ipsilateral ICA. A combination of both preoperative embolization and carotid stenting allowed a less hazardous radical resection of the CBT. An almost bloodless surgical field permitted meticulous dissection, hence reducing the risk of intraoperative vascular and nerve injury. Embolization and carotid stenting prior to surgical resection should be considered in cases with bilateral CBT or a skull base orientated high CBT, and for those with intracranial extension and patients who have failed the TBO test. Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  1. Modulation of the hypoxic sensory response of the carotid body by 5-hydroxytryptamine: role of the 5-HT2 receptor.

    PubMed

    Jacono, F J; Peng, Y-J; Kumar, G K; Prabhakar, N R

    2005-02-15

    Previous studies have shown that glomus cells of the carotid body express 5-hydroxytryptamine (5-HT). The aim of this study was to elucidate the role of 5-HT on the hypoxic sensory response (HSR) of the carotid body. Sensory activity was recorded from multi-fiber (n=16) and single-fiber (n=8) preparations of ex vivo carotid bodies harvested from anesthetized, adult rats. 5-HT (3 microM) had no significant effect on the magnitude or on the onset of the HSR. However, 5-HT consistently prolonged the time necessary for the sensory activity to return to baseline following the termination of the hypoxic challenge. Ketanserin (40 microM), a 5-HT2 receptor antagonist completely prevented 5-HT-induced prolongation of the HSR, whereas had no effect on the control HSR (onset, magnitude, and time for decay without 5-HT). Carotid bodies expressed 5-HT, but hypoxia did not facilitate 5-HT release. These observations suggest that 5-HT is not critical for the HSR of the rat carotid body, but it modulates the dynamics of the HSR via its action on 5-HT2 receptors.

  2. The general ultrastructure of the carotid body of the domestic fowl.

    PubMed

    Hodges, R D; King, A S; King, D Z; French, E I

    1975-10-27

    Electron microscopic studies of the carotid body of the domestic fowl (Gallus gallus domesticus) have shown Type I and Type II cells combined with axons into compact groups. The many Type I cells in the depths of the organ had a body, containing the nucleus, and an elongated, flared process. Some of the Type I cells in the superficial regions tended to be spindle-shaped. Type I cells were characterised by membrane-bound, dense-cored vesicles about 120 nm in diameter. Type II cells invested the Type I cells and had axons embedded in them as in Schwann cells. The fine structure of the carotid body in the domestic fowl resembles that of the Lovebird (Uroloncha domestica) and of various amphibia and mammals. The possibility is discussed that the Type I cells may have a chemoreceptor or a general secretory function, or even both of these axons leading to or from Type I cells. The main role of the Type II cells seems to be to provide a pathway for functions together.

  3. A pilot study of the body weight of pure-bred client-owned adult cats.

    PubMed

    Kienzle, Ellen; Moik, Katja

    2011-10-01

    A total of 539 pure-bred and seventy-five cats without a pedigree were weighed and scored at cat shows or in veterinary surgeries. Data from normal-weight cats with a body condition score (BCS) of 5 (ideal) were only used. Breeds were grouped into five classes. For female cats, the mean weight for these groups were as follows: very light (2.8 kg); light (3.2 kg); medium (3.5 kg); large (4.0 kg); giant (4.9) kg. For male cats, the corresponding values were 3.6, 4.2, 4.3, 5.1 and 6.1 kg. Siamese/Oriental Shorthair were identified as a very light breed, the Norwegian Forest and the Siberian Cat as a large breed and the Maine Coon as a giant breed. Males and females of the same breed did not always belong to the same class. In some breeds, individuals of the same sex were found in two different classes. The percentage of intact overweight cats (BCS >5) was low (7 % of intact males, 3 % of intact females). Incidence of overweight in neutered cats was 50 % in males and 38 % in females. Among pedigreed cats, there were differences in the incidence of overweight in neutered cats: high in Norwegian Forest Cats (males 75 %, females 50 %) and low in Siamese/Oriental Shorthair Cats (males 25 %, females 1 %). Cats with a BCS of 6, 7 and 8 had on average 120, 154 and 214 % of the normal weight of their breed, respectively.

  4. CaV3.2 T-type Ca²⁺ channels in H₂S-mediated hypoxic response of the carotid body.

    PubMed

    Makarenko, Vladislav V; Peng, Ying-Jie; Yuan, Guoxiang; Fox, Aaron P; Kumar, Ganesh K; Nanduri, Jayasri; Prabhakar, Nanduri R

    2015-01-15

    Arterial blood O2 levels are detected by specialized sensory organs called carotid bodies. Voltage-gated Ca(2+) channels (VGCCs) are important for carotid body O2 sensing. Given that T-type VGCCs contribute to nociceptive sensation, we hypothesized that they participate in carotid body O2 sensing. The rat carotid body expresses high levels of mRNA encoding the α1H-subunit, and α1H protein is localized to glomus cells, the primary O2-sensing cells in the chemoreceptor tissue, suggesting that CaV3.2 is the major T-type VGCC isoform expressed in the carotid body. Mibefradil and TTA-A2, selective blockers of the T-type VGCC, markedly attenuated elevation of hypoxia-evoked intracellular Ca(2+) concentration, secretion of catecholamines from glomus cells, and sensory excitation of the rat carotid body. Similar results were obtained in the carotid body and glomus cells from CaV3.2 knockout (Cacna1h(-/-)) mice. Since cystathionine-γ-lyase (CSE)-derived H2S is a critical mediator of the carotid body response to hypoxia, the role of T-type VGCCs in H2S-mediated O2 sensing was examined. Like hypoxia, NaHS, a H2S donor, increased intracellular Ca(2+) concentration and augmented carotid body sensory nerve activity in wild-type mice, and these effects were markedly attenuated in Cacna1h(-/-) mice. In wild-type mice, TTA-A2 markedly attenuated glomus cell and carotid body sensory nerve responses to hypoxia, and these effects were absent in CSE knockout mice. These results demonstrate that CaV3.2 T-type VGCCs contribute to the H2S-mediated carotid body response to hypoxia. Copyright © 2015 the American Physiological Society.

  5. CaV3.2 T-type Ca2+ channels in H2S-mediated hypoxic response of the carotid body

    PubMed Central

    Makarenko, Vladislav V.; Peng, Ying-Jie; Yuan, Guoxiang; Fox, Aaron P.; Kumar, Ganesh K.; Nanduri, Jayasri

    2014-01-01

    Arterial blood O2 levels are detected by specialized sensory organs called carotid bodies. Voltage-gated Ca2+ channels (VGCCs) are important for carotid body O2 sensing. Given that T-type VGCCs contribute to nociceptive sensation, we hypothesized that they participate in carotid body O2 sensing. The rat carotid body expresses high levels of mRNA encoding the α1H-subunit, and α1H protein is localized to glomus cells, the primary O2-sensing cells in the chemoreceptor tissue, suggesting that CaV3.2 is the major T-type VGCC isoform expressed in the carotid body. Mibefradil and TTA-A2, selective blockers of the T-type VGCC, markedly attenuated elevation of hypoxia-evoked intracellular Ca2+ concentration, secretion of catecholamines from glomus cells, and sensory excitation of the rat carotid body. Similar results were obtained in the carotid body and glomus cells from CaV3.2 knockout (Cacna1h−/−) mice. Since cystathionine-γ-lyase (CSE)-derived H2S is a critical mediator of the carotid body response to hypoxia, the role of T-type VGCCs in H2S-mediated O2 sensing was examined. Like hypoxia, NaHS, a H2S donor, increased intracellular Ca2+ concentration and augmented carotid body sensory nerve activity in wild-type mice, and these effects were markedly attenuated in Cacna1h−/− mice. In wild-type mice, TTA-A2 markedly attenuated glomus cell and carotid body sensory nerve responses to hypoxia, and these effects were absent in CSE knockout mice. These results demonstrate that CaV3.2 T-type VGCCs contribute to the H2S-mediated carotid body response to hypoxia. PMID:25377087

  6. Dopaminergic metabolism in carotid bodies and high-altitude acclimatization in female rats.

    PubMed

    Joseph, Vincent; Soliz, Jorge; Soria, Ruddy; Pequignot, Jacqueline; Favier, Roland; Spielvogel, Hilde; Pequignot, Jean Marc

    2002-03-01

    We tested the hypothesis that ovarian steroids stimulate breathing through a dopaminergic mechanism in the carotid bodies. In ovariectomized female rats raised at sea level, domperidone, a peripheral D2-receptor antagonist, increased ventilation in normoxia (minute ventilation = +55%) and acute hypoxia (+32%). This effect disappeared after 10 daily injections of ovarian steroids (progesterone + estradiol). At high altitude (3,600 m, Bolivian Institute for High-Altitude Biology-IBBA, La Paz, Bolivia), neutered females had higher carotid body tyrosine hydroxylase activity (the rate-limiting enzyme for catecholamine synthesis: +129%) and dopamine utilization (+150%), lower minute ventilation (-30%) and hypoxic ventilatory response (-57%), and higher hematocrit (+18%) and Hb concentration (+21%) than intact female rats. Consistent signs of arterial pulmonary hypertension (right ventricular hypertrophy) also appeared in ovariectomized females. None of these parameters was affected by gonadectomy in males. Our results show that ovarian steroids stimulate breathing by lowering a peripheral dopaminergic inhibitory drive. This process may partially explain the deacclimatization of postmenopausal women at high altitude.

  7. Single and combined effects of body composition phenotypes on carotid intima-media thickness.

    PubMed

    Melo, X; Santa-Clara, H; Santos, D A; Pimenta, N M; Pinto, R; Minderico, C S; Fernhall, B; Sardinha, L B

    2016-08-01

    Central fatness might be a more sensitive predictor of atherosclerotic changes in children than are total body fat measures. However, it is unclear whether a total body fat measure coupled with an estimate of a more central pattern of fat accumulation predicts increased carotid intima-media-thickness (cIMT) better than either measure alone. The objective of the study is to identify the ability of a combination of simple anthropometric screening tools or a combination of objective measures of body composition to predict cIMT. cIMT was assessed on the common carotid artery in 349 children aged 11-12 years old (183 girls). Body mass index (BMI), waist circumference (WC) and waist-to-height ratio (WHtR) were dichotomized according to established criteria and indices of total body (TBFI) and abdominal (ABFMI) fat were assessed by dual-energy X-ray absorptiometry and categorized (increased risk ≥85%). Single and combined associations among anthropometric and laboratorial measures with the risk of having increased cIMT (≥85%) and discriminatory performance were tested with logistic regression analysis and Receiver Operator Curve analysis. Children with higher total fatness (BMI and TBFI) or higher central pattern of fat accumulation (WC, WHtR and BFMI) were in higher risk for increased cIMT [odds ratio (OR): 2.08-3.24). The risk for increased cIMT was not higher among children who coupled high total and high central fatness (OR: 2.27-3.10). Combination of total and central measures of fat does not improve the prediction of increased cIMT in children. Simple surrogate measures of fatness can be used to predict increased cIMT urging special attention to those children who exhibit increased abdominal fat. © 2015 World Obesity.

  8. Effects of low oxygen on the release of dopamine from the rabbit carotid body in vitro

    PubMed Central

    Fidone, S.; Gonzalez, C.; Yoshizaki, K.

    1982-01-01

    1. Rabbit carotid bodies were pre-loaded with [3H]dopamine (DA) synthesized from [3H]tyrosine and then mounted in a vertical drop-type superfusion chamber which permitted simultaneous collection of released [3H]DA and recording of chemoreceptor discharge from the carotid sinus nerve. 2. The time course of the spontaneous release of [3H]DA (superfusion with media equilibrated with 100% O2) in the presence of monoamine oxidase inhibitors exhibited two linear components, an initial steep phase followed after 3-4 hr by a later slower phase of release. 3. When a 5 min low O2 stimulus was delivered during the initial steep linear component of resting [3H]DA release, there was an abrupt increase in release, the magnitude of which was stimulus-dependent. 4. The efflux of total radioactivity from the preparation declined exponentially with time; under resting conditions it was principally non-metabolized [3H]tyrosine. During stimulation, however the efflux increased, and 60-80% of the radioactivity could be attributed to [3H]DA. 5. For a given low O2 stimulus, the ratio of [3H]DA release during the stimulus period over that in the preceding control period remained approximately the same throughout a single experiment. Ratios for different low O2 stimuli (50, 40, 30, 20, 10 and 0% O2 in N2) yielded a parabolic relationship when plotted against stimulus intensity. 6. Transection of the carotid sinus nerve or removal of the superior cervical ganglion 12-15 days prior to the experiment did not affect the release of [3H]DA at moderate stimulus intensities (superfusion with media equilibrated with 30% or 10% O2 in N2) but both procedures significantly depressed release at the highest stimulus intensity (100% N2). 7. Chemoreceptor discharge and [3H]DA release were simultaneously monitored in experiments using superfusion media free of monoamine oxidase inhibitors. In these experiments, the efflux of [3H]dihydroxyphenyl acetic acid (DOPAC) was also measured. The increase in peak

  9. Retrobulbar lymphoma associated with a ballistic foreign body in a cat.

    PubMed

    Robat, C; Bemelmans, I; Marescaux, L

    2016-04-01

    A seven-year-old domestic shorthair cat, adopted 5 years previously with a corneal perforation of the left eye, was presented for investigation of a left orbital mass. Computed tomography revealed a metallic foreign body within a contrast-enhancing, heterogeneous orbital mass. Large cell lymphoma was diagnosed from a fine needle aspirate. The cat staged negatively and was treated with L-asparaginase, prednisolone and three fractions of radiation therapy. A rapid clinical remission was obtained and the cat remained in remission for 3 years after therapy. This is the first report of large cell lymphoma likely occurring secondary to a foreign body.

  10. Peptide receptor radionuclide therapy with (177)Lu DOTATATE in a case of recurrent carotid body paraganglioma with spinal metastases.

    PubMed

    Gupta, Santosh Kumar; Singla, Suhas; Karunanithi, Sellam; Damle, Nishikant; Bal, Chandrasekhar

    2014-05-01

    Paragangliomas are rare benign neuroendocrine tumors, and 80% of all paragangliomas are either carotid body tumors or glomus jugulare tumors. We present a case of recurrent unresectable carotid body paraganglioma with nodal and T7 vertebral metastases in a 30-year-old man 6 years postsurgery detected with Ga DOTANOC PET/CT and was administered with peptide receptor radionuclide therapy using Lu DOTATATE. After 5 cycles of Lu DOTATATE (total cumulative activity of 750 mCi [27 GBq]), significant response at the primary site on Ga DOTANOC PET/CT and complete disappearance of nodal and T7 vertebral metastases were noted.

  11. Sewing needle foreign body ingestion in dogs and cats: 65 cases (2000-2012).

    PubMed

    Pratt, Chap L; Reineke, Erica L; Drobatz, Kenneth J

    2014-08-01

    To characterize clinical signs, diagnostic test results, foreign body location, treatment, and outcome for dogs and cats with sewing needle foreign bodies. Retrospective case series. 65 dogs and cats with sewing needle foreign bodies. Medical records of 27 dogs and 38 cats examined because of sewing needle foreign bodies from January 2000 to February 2012 were reviewed for signalment, medical history, physical examination findings, diagnostic test results, interval from witnessed exposure and radiographic imaging to definitive treatment, definitive treatment, sewing needle location, complications, and outcome. 7 (10.8%) animals had sewing needles in extragastrointestinal locations that were not causing clinical signs. The remaining 58 (89.2%) animals had known sewing needle exposure or acute clinical signs associated with ingestion. The esophageal and gastric regions were the most common location for a sewing needle (10/21 [47.6%] dogs; 19/37 [51.4%] cats), followed by the oropharynx (7/21 [33.3%] dogs; 11/37 [29.7%] cats) and small and large intestines (4/21 [19.0%] dogs; 7/37 [18.9%] cats). Gastrointestinal perforation was detected in 10 of 58 (17.2%) animals (5/21 [23.8%] dogs; 5/37 [13.5%] cats). Sewing needles in the esophagus and stomach were successfully removed endoscopically in 8 of 9 dogs and 18 of 19 cats. Survival rate was 98.1% (51/52) for animals receiving definitive treatment. Endoscopic removal of ingested sewing needles was highly successful and should be recommended to prevent gastrointestinal tract perforation and associated morbidity. Prognosis for dogs and cats receiving definitive treatment for sewing needle foreign body ingestion was excellent.

  12. Heinz body formation in cats fed baby food containing onion powder.

    PubMed

    Robertson, J E; Christopher, M M; Rogers, Q R

    1998-04-15

    To determine whether cats fed baby food with onion powder develop Heinz bodies and anemia and to establish a dose-response relation between dietary onion powder content and Heinz body formation. Prospective study. 42 healthy, adult, specific-pathogen-free cats. Commercial baby food with and without onion powder was fed to 2 groups of 6 cats for 5 weeks. Heinz body percentage, PCV, reticulocyte percentage, turbidity index, and methemoglobin and reduced glutathione concentrations were determined twice weekly and then weekly for 4 weeks following removal of the diet. For the dose-response study, 5 groups of 6 cats were fed a canned diet for 2 months that contained 0, 0.3, 0.75, 1.5, or 2.5% onion powder. Heinz body percentage, PCV, and reticulocyte percentage were determined twice weekly. Compared with cats fed baby food without onion powder, cats ingesting baby food with onion powder had significantly higher Heinz body percentages that peaked at 33 to 53%. Methemoglobin concentration also significantly increased but did not exceed 1.2%. Glutathione concentration, PCV, and food intake did not differ between the 2 groups. Rate and degree of Heinz body formation differed significantly between various onion powder concentrations fed. Compared with 0% onion powder, the diet with 2.5% onion powder caused a significant decrease in PCV and an increased punctate reticulocyte percentage. Baby food or other foods containing similar amounts of onion powder should be avoided for use in cats because of Heinz body formation and the potential for development of anemia, particularly with high food intake. Cats with diseases associated with oxidative stress may develop additive hemoglobin damage when fed baby food containing onion powder.

  13. The relationship between distribution of body fat mass and carotid artery intima-media thickness in Korean older adults.

    PubMed

    Park, Jin-Kee; Park, Hyuntae; Kim, Kwi-Baek

    2015-10-01

    [Purpose] The aim of this study was to examine the relationships between the amount and distribution of body fat and the carotid intima-media thickness to explore whether coronary artery disease risk may be mediated through effects on the amount of fat mass in older adults. [Subjects and Methods] A total of 200 elderly females was participated. The percentage of body fat mass was measured by the bioelectrical impedance analysis method, and the carotid intima-media thickness was measured by B-mode ultrasound. Analysis of covariance was performed to assess independent associations between the four categories of percentage of body fat mass and the carotid intima-media thickness after multivariate adjustment. Logistic regression analyses were utilized to calculate odds ratios and 95% confidence intervals for examining independent associations between percentage of body fat mass and the estimated risk of coronary artery disease. [Results] Analysis of covariance showed that the carotid intima-media thickness was significantly thick in both obesity and overweight groups. When multivariate-adjusted OR for the estimated risk of coronary artery disease, the odds ratios for the obesity and overweight groups were 3.0 (95% confidence interval, 1.1 to 8.7) and 2.5 (95% confidence interval, 1.0 to 6.1), respectively. [Conclusion] This study demonstrates that elderly females with a high body fat mass are more likely to have the estimated risk of CAD than who fit body fat mass in elderly female.

  14. The relationship between distribution of body fat mass and carotid artery intima-media thickness in Korean older adults

    PubMed Central

    Park, Jin-Kee; Park, Hyuntae; Kim, Kwi-Baek

    2015-01-01

    [Purpose] The aim of this study was to examine the relationships between the amount and distribution of body fat and the carotid intima-media thickness to explore whether coronary artery disease risk may be mediated through effects on the amount of fat mass in older adults. [Subjects and Methods] A total of 200 elderly females was participated. The percentage of body fat mass was measured by the bioelectrical impedance analysis method, and the carotid intima-media thickness was measured by B-mode ultrasound. Analysis of covariance was performed to assess independent associations between the four categories of percentage of body fat mass and the carotid intima-media thickness after multivariate adjustment. Logistic regression analyses were utilized to calculate odds ratios and 95% confidence intervals for examining independent associations between percentage of body fat mass and the estimated risk of coronary artery disease. [Results] Analysis of covariance showed that the carotid intima-media thickness was significantly thick in both obesity and overweight groups. When multivariate-adjusted OR for the estimated risk of coronary artery disease, the odds ratios for the obesity and overweight groups were 3.0 (95% confidence interval, 1.1 to 8.7) and 2.5 (95% confidence interval, 1.0 to 6.1), respectively. [Conclusion] This study demonstrates that elderly females with a high body fat mass are more likely to have the estimated risk of CAD than who fit body fat mass in elderly female. PMID:26633917

  15. Signal transduction of aortic and carotid sinus baroreceptors is not modified by central command during spontaneous motor activity in decerebrate cats.

    PubMed

    Matsukawa, Kanji; Ishii, Kei; Kadowaki, Akito; Ishida, Tomoko; Idesako, Mitsuhiro; Liang, Nan

    2014-05-15

    Our laboratory has suggested that central command provides selective inhibition of the cardiomotor component of aortic baroreflex at the start of exercise, preserving carotid sinus baroreflex. It is postulated that central command may modify the signal transduction of aortic baroreceptors, so as to decrease aortic baroreceptor input to the cardiovascular centers, and, thereby, can cause the selective inhibition of aortic baroreflex. To test the hypothesis, we directly analyzed the responses in multifiber aortic nerve activity (AoNA) and carotid sinus nerve activity (CsNA) during spontaneous motor activity in decerebrate, paralyzed cats. The increases of 62-104% in mean AoNA and CsNA were found during spontaneous motor activity, in proportion to a rise of 35 ± 3 mmHg (means ± SE) in mean arterial blood pressure (MAP), and had an attenuating tendency by restraining heart rate (HR) at the lower intrinsic frequency of 154 ± 6 beats/min. Brief occlusion of the abdominal aorta was conducted before and during spontaneous motor activity to produce a mechanically evoked increase in MAP and, thereby, to examine the stimulus-response relationship of arterial baroreceptors. Although the sensitivity of the MAP-HR baroreflex curve was markedly blunted during spontaneous motor activity, the stimulus-response relationships of AoNA and CsNA were not influenced by spontaneous motor activity, irrespective of the absence or presence of the HR restraint. Thus, it is concluded that aortic and carotid sinus baroreceptors can code beat-by-beat blood pressure during spontaneous motor activity in decerebrate cats and that central command is unlikely to modulate the signal transduction of arterial baroreceptors. Copyright © 2014 the American Physiological Society.

  16. Impaired ventilatory acclimatization to hypoxia in female mice overexpressing erythropoietin: unexpected deleterious effect of estradiol in carotid bodies.

    PubMed

    Gassmann, Max; Pfistner, Christine; Doan, Van Diep; Vogel, Johannes; Soliz, Jorge

    2010-12-01

    Apart from enhancing the production of red blood cells, erythropoietin (Epo) alters the ventilatory response when oxygen supply is reduced. We recently demonstrated that Epo's beneficial effect on the ventilatory response to acute hypoxia is sex dependent, with female mice being better able to cope with reduced oxygenation. In the present work, we hypothesized that ventilatory acclimatization to chronic hypoxia (VAH) in transgenic female mice (Tg6) harboring high levels of Epo in the brain and blood will also be improved compared with wild-type (WT) animals. Surprisingly, VAH was blunted in Tg6 female mice. To define whether this phenomenon had a central (brain stem respiratory centers) and/or peripheral (carotid bodies) origin, a bilateral transection of carotid sinus nerve (chemodenervation) was performed. This procedure allowed the analysis of the central response in the absence of carotid body information. Interestingly, chemodenervation restored the VAH in Tg6 mice, suggesting that carotid bodies were responsible for the blunted response. Coherently with this observation, the sensitivity to oxygen alteration in arterial blood (Dejour test) after chronic hypoxia was lower in transgenic carotid bodies compared with the WT control. As blunted VAH occurred in female but not male transgenic mice, the involvement of sex female steroids was obvious. Indeed, measurement of sexual female hormones revealed that the estradiol serum level was 4 times higher in transgenic mice Tg6 than in WT animals. While ovariectomy decreased VAH in WT females, this treatment restored VAH in Tg6 female mice. In line with this observation, injections of estradiol in ovariectomized Tg6 females dramatically reduced the VAH. We concluded that during chronic hypoxia, estradiol in carotid bodies suppresses the Epo-mediated elevation of ventilation. Considering the increased application of recombinant Epo for a variety of disorders, our data imply the need to take the patient's hormonal status

  17. Acute oxygen sensing by the carotid body: from mitochondria to plasma membrane.

    PubMed

    Chang, Andy J

    2017-08-17

    Maintaining oxygen homeostasis is crucial to the survival of animals. Mammals respond acutely to changes in blood oxygen levels by modulating cardiopulmonary function. The major sensor of blood oxygen that regulates breathing is the carotid body (CB), a small chemosensory organ located at the carotid bifurcation. When arterial blood oxygen levels drop in hypoxia, neuroendocrine cells in the CB called glomus cells are activated to signal to afferent nerves that project to the brainstem. The mechanism by which hypoxia stimulates CB sensory activity has been the subject of many studies over the last 90 years. Two discrete models emerged that argue for the seat of oxygen sensing to lie either in the plasma membrane or mitochondria of CB cells. Recent studies are bridging the gap between these models by identifying hypoxic signals generated by changes in mitochondrial function in the CB that can be sensed by plasma membrane proteins on glomus cells. The CB is important for physiological adaptation to hypoxia, and its dysfunction contributes to sympathetic hyperactivity in common conditions such as sleep-disordering breathing, chronic heart failure, and insulin resistance. Understanding the basic mechanism of oxygen sensing in the CB could allow us to develop strategies to target this organ for therapy. In this short review, I will describe two historical models of CB oxygen sensing and new findings that are integrating these models. Copyright © 2017, Journal of Applied Physiology.

  18. The von Hippel-Lindau Chuvash mutation in mice causes carotid-body hyperplasia and enhanced ventilatory sensitivity to hypoxia.

    PubMed

    Slingo, Mary E; Turner, Philip J; Christian, Helen C; Buckler, Keith J; Robbins, Peter A

    2014-04-01

    The hypoxia-inducible factor (HIF) family of transcription factors coordinates diverse cellular and systemic responses to hypoxia. Chuvash polycythemia (CP) is an autosomal recessive disorder in humans in which there is impaired oxygen-dependent degradation of HIF, resulting in long-term systemic elevation of HIF levels at normal oxygen tensions. CP patients demonstrate the characteristic features of ventilatory acclimatization to hypoxia, namely, an elevated baseline ventilation and enhanced acute hypoxic ventilatory response (AHVR). We investigated the ventilatory and carotid-body phenotype of a mouse model of CP, using whole-body plethysmography, immunohistochemistry, and electron microscopy. In keeping with studies in humans, CP mice had elevated ventilation in euoxia and a significantly exaggerated AHVR when exposed to 10% oxygen, with or without the addition of 3% carbon dioxide. Carotid-body immunohistochemistry demonstrated marked hyperplasia of the oxygen-sensing type I cells, and the cells themselves appeared enlarged with more prominent nuclei. This hypertrophy was confirmed by electron microscopy, which also revealed that the type I cells contained an increased number of mitochondria, enlarged dense-cored vesicles, and markedly expanded rough endoplasmic reticulum. The morphological and ultrastructural changes seen in the CP mouse carotid body are strikingly similar to those observed in animals exposed to chronic hypoxia. Our study demonstrates that the HIF pathway plays a major role, not only in regulating both euoxic ventilatory control and the sensitivity of the response to hypoxia, but also in determining the morphology of the carotid body.

  19. The von Hippel-Lindau Chuvash mutation in mice causes carotid-body hyperplasia and enhanced ventilatory sensitivity to hypoxia

    PubMed Central

    Slingo, Mary E.; Turner, Philip J.; Christian, Helen C.; Buckler, Keith J.

    2013-01-01

    The hypoxia-inducible factor (HIF) family of transcription factors coordinates diverse cellular and systemic responses to hypoxia. Chuvash polycythemia (CP) is an autosomal recessive disorder in humans in which there is impaired oxygen-dependent degradation of HIF, resulting in long-term systemic elevation of HIF levels at normal oxygen tensions. CP patients demonstrate the characteristic features of ventilatory acclimatization to hypoxia, namely, an elevated baseline ventilation and enhanced acute hypoxic ventilatory response (AHVR). We investigated the ventilatory and carotid-body phenotype of a mouse model of CP, using whole-body plethysmography, immunohistochemistry, and electron microscopy. In keeping with studies in humans, CP mice had elevated ventilation in euoxia and a significantly exaggerated AHVR when exposed to 10% oxygen, with or without the addition of 3% carbon dioxide. Carotid-body immunohistochemistry demonstrated marked hyperplasia of the oxygen-sensing type I cells, and the cells themselves appeared enlarged with more prominent nuclei. This hypertrophy was confirmed by electron microscopy, which also revealed that the type I cells contained an increased number of mitochondria, enlarged dense-cored vesicles, and markedly expanded rough endoplasmic reticulum. The morphological and ultrastructural changes seen in the CP mouse carotid body are strikingly similar to those observed in animals exposed to chronic hypoxia. Our study demonstrates that the HIF pathway plays a major role, not only in regulating both euoxic ventilatory control and the sensitivity of the response to hypoxia, but also in determining the morphology of the carotid body. PMID:24030664

  20. [Transformation of neuronal activity in the cat lateral geniculate body].

    PubMed

    Silakov, V L

    1976-05-01

    The neuronal activity transformations were studied in the cat LGB under the action of nembutal, light stimulation, and micropolarization of geniculate cells. The transformation of single spike activity into bursts was found to reflect the inhibitory state of the neurons. Their excitation entailed a reverse transformation. Short feed-back connections functioning within the microsystems of LGB neurons are supposed to underlie the transformations.

  1. Hypoxic pulmonary vasoconstriction, carotid body function and erythropoietin production in adult rats perinatally exposed to hyperoxia.

    PubMed

    Prieto-Lloret, Jesus; Ramirez, Maria; Olea, Elena; Moral-Sanz, Javier; Cogolludo, Angel; Castañeda, Javier; Yubero, Sara; Agapito, Teresa; Gomez-Niño, Angela; Rocher, Asuncion; Rigual, Ricardo; Obeso, Ana; Perez-Vizcaino, Francisco; González, Constancio

    2015-06-01

    Adult animals that have been perinatally exposed to oxygen-rich atmospheres (hyperoxia), recalling those used for oxygen therapy in infants, exhibit a loss of hypoxic pulmonary vasoconstriction, whereas vasoconstriction elicited by depolarizing agents is maintained. Loss of pulmonary hypoxic vasoconstriction is not linked to alterations in oxygen-sensitive K(+) currents in pulmonary artery smooth muscle cells. Loss of hypoxic vasoconstriction is associated with early postnatal oxidative damage and corrected by an antioxidant diet. Perinatal hyperoxia damages carotid body chemoreceptor cell function and the antioxidant diet does not reverse it. The hypoxia-elicited increase in erythropoietin plasma levels is not affected by perinatal hyperoxia. The potential clinical significance of the findings in clinical situations such as pneumonia, chronic obstructive pulmonary disease or general anaesthesia is considered. Adult mammalians possess three cell systems that are activated by acute bodily hypoxia: pulmonary artery smooth muscle cells (PASMC), carotid body chemoreceptor cells (CBCC) and erythropoietin (EPO)-producing cells. In rats, chronic perinatal hyperoxia causes permanent carotid body (CB) atrophy and functional alterations of surviving CBCC. There are no studies on PASMC or EPO-producing cells. Our aim is to define possible long-lasting functional changes in PASMC or EPO-producing cells (measured as EPO plasma levels) and, further, to analyse CBCC functional alterations. We used 3- to 4-month-old rats born and reared in a normal atmosphere or exposed to perinatal hyperoxia (55-60% O2 for the last 5-6 days of pregnancy and 4 weeks after birth). Perinatal hyperoxia causes an almost complete loss of hypoxic pulmonary vasoconstriction (HPV), which was correlated with lung oxidative status in early postnatal life and prevented by antioxidant supplementation in the diet. O2 -sensitivity of K(+) currents in the PASMC of hyperoxic animals is normal, indicating that

  2. Hypoxic pulmonary vasoconstriction, carotid body function and erythropoietin production in adult rats perinatally exposed to hyperoxia

    PubMed Central

    Prieto-Lloret, Jesus; Ramirez, Maria; Olea, Elena; Moral-Sanz, Javier; Cogolludo, Angel; Castañeda, Javier; Yubero, Sara; Agapito, Teresa; Gomez-Niño, Angela; Rocher, Asuncion; Rigual, Ricardo; Obeso, Ana; Perez-Vizcaino, Francisco; González, Constancio

    2015-01-01

    Adult mammalians possess three cell systems that are activated by acute bodily hypoxia: pulmonary artery smooth muscle cells (PASMC), carotid body chemoreceptor cells (CBCC) and erythropoietin (EPO)-producing cells. In rats, chronic perinatal hyperoxia causes permanent carotid body (CB) atrophy and functional alterations of surviving CBCC. There are no studies on PASMC or EPO-producing cells. Our aim is to define possible long-lasting functional changes in PASMC or EPO-producing cells (measured as EPO plasma levels) and, further, to analyse CBCC functional alterations. We used 3- to 4-month-old rats born and reared in a normal atmosphere or exposed to perinatal hyperoxia (55–60% O2 for the last 5–6 days of pregnancy and 4 weeks after birth). Perinatal hyperoxia causes an almost complete loss of hypoxic pulmonary vasoconstriction (HPV), which was correlated with lung oxidative status in early postnatal life and prevented by antioxidant supplementation in the diet. O2-sensitivity of K+ currents in the PASMC of hyperoxic animals is normal, indicating that their inhibition is not sufficient to trigger HPV. Perinatal hyperoxia also abrogated responses elicited by hypoxia on catecholamine and cAMP metabolism in the CB. An increase in EPO plasma levels elicited by hypoxia was identical in hyperoxic and control animals, implying a normal functioning of EPO-producing cells. The loss of HPV observed in adult rats and caused by perinatal hyperoxia, comparable to oxygen therapy in premature infants, might represent a previously unrecognized complication of such a medical intervention capable of aggravating medical conditions such as regional pneumonias, atelectases or general anaesthesia in adult life. Key points Adult animals that have been perinatally exposed to oxygen-rich atmospheres (hyperoxia), recalling those used for oxygen therapy in infants, exhibit a loss of hypoxic pulmonary vasoconstriction, whereas vasoconstriction elicited by depolarizing agents is

  3. Tracheobronchial foreign bodies in cats: a retrospective study of 12 cases.

    PubMed

    Leal, Rodolfo Oliveira; Bongrand, Yannick; Lepoutre, Julie Gallay; Gomes, Eymeric; Hernandez, Juan

    2017-02-01

    Objectives The aim of the study was to evaluate age, sex, breed, clinical signs, time between onset of signs and presentation, diagnostic procedures, method of extraction, location and nature of foreign bodies (FBs) in confirmed cases of tracheobronchial FBs in cats. We hypothesised that bronchoscopy was effective in extracting tracheobronchial FBs in cats. Methods A retrospective study was performed using clinical reports from three private practices in France between May 2009 and November 2014. Cats were included if an intraluminal tracheobronchial FB had been identified and extracted (either by bronchoscopy or surgery). Results Twelve cats (six male, six female) were included. Mean age was 3.75 ± 2.5 years. Coughing was the main complaint and was present in 9/12 (75%) of the cats. Thoracic radiographs were obtained in 12/12 cats (100%) and a FB was suspected in 11/12 (92%). Bronchoscopy was performed in all of the cats and enabled FB extraction in 10/12 (83%) of them. In 2/12 cats (17%), an additional surgical approach was required. In 6/12 (50%) cats, FBs were located in the trachea, while in 6/12 (50%) cats FBs were in the bronchial tree, particularly in the right caudal bronchus (4/6; 66%). Seven of 12 (58%) FBs were vegetal in nature, 3/12 (25%) were mineral and 2/12 (17%) were undetermined. All the mineral FBs were extracted from the trachea, while the majority of the vegetal ones (5/7; 71%) were found in the bronchi. Conclusions and relevance Feline respiratory FBs can be found in the trachea and in the bronchial tree, particularly in the right caudal bronchus. Vegetal FBs tend to migrate through the bronchial tree, whereas mineral ones tend to lodge in the trachea. Bronchoscopy seems to be a highly effective procedure for the extraction of tracheobronchial FBs in cats.

  4. Blood pressure, heart rate and arterial blood gas reactions to acute hypoxia in carotid body denervated spontaneously hypertensive rats.

    PubMed

    Huckstorf, C; Behm, R; Habeck, J O; Rückborn, K; Franz, U

    1987-01-01

    The role of the peripheral arterial chemoreceptors in the reflex control of respiration and the cardiovascular systems was studied in spontaneously hypertensive rats (SHR). In carotid body denervated and in sham-operated control rats mean arterial blood pressure, heart rate, respiratory rate and arterial blood gases were measured under normoxic conditions and in acute normobaric hypoxia. Under normoxia the carotid body denervated SHR differ from the sham-operated ones only in significantly lowered arterial pO2 and pH and in significantly increased pCO2 values. The carotid body denervated SHR react to acute hypoxia with a significantly smaller increase in respiratory rate, a more pronounced fall in the arterial pO2 and a greater decrease in mean arterial blood pressure than the sham-operated control rats. Our results suggest that carotid body chemoreceptors in SHR are of great importance in regulating respiration but of secondary consequence regarding the reflex control of the cardiovascular system.

  5. Volatile Anaesthetic Depression of the Carotid Body Chemoreflex-Mediated Ventilatory Response to Hypoxia: Directions for Future Research

    PubMed Central

    Pandit, J. J.

    2014-01-01

    In assessing whether volatile anaesthetics directly depress the carotid body response to hypoxia it is necessary to combine in meta-analysis studies of when it is “functionally isolated” (e.g., recordings are made from its afferent nerve). Key articles were retrieved (full papers in English) and subjected to quantitative analysis to yield an aggregate estimate of effect. Results from articles that did not use such methodology were assessed separately from this quantitative approach, to see what could be learned also from a nonquantitative overview. Just 7 articles met the inclusion criteria for hypoxia and just 6 articles for hypercapnia. Within these articles, the anaesthetic (mean dose 0.75, standard deviation (SD) 0.40 minimum alveolar concentration, MAC) statistically significantly depressed carotid body hypoxic response by 24% (P = 0.041), but a similar dose (mean 0.81 (0.42) MAC) did not affect the hypercapnic response. The articles not included in the quantitative analysis (31 articles), assessed qualitatively, also indicated that anaesthetics depress carotid body function. This conclusion helps direct future research on the anaesthetic effects on putative cellular/molecular processes that underlie the transduction of hypoxia in the carotid body. PMID:24808974

  6. Chemotransduction in the Carotid Body: K+ Current Modulated by Po2 in Type I Chemoreceptor Cells

    NASA Astrophysics Data System (ADS)

    Lopez-Barneo, Jose; Lopez-Lopez, Jose R.; Urena, Juan; Gonzalez, Constancio

    1988-07-01

    The ionic currents of carotid body type I cells and their possible involvement in the detection of oxygen tension (Po2) in arterial blood are unknown. The electrical properties of these cells were studied with the whole-cell patch clamp technique, and the hypothesis that ionic conductances can be altered by changes in Po2 was tested. The results show that type I cells have voltage-dependent sodium, calcium, and potassium channels. Sodium and calcium currents were unaffected by a decrease in Po2 from 150 to 10 millimeters of mercury, whereas, with the same experimental protocol, potassium currents were reversibly reduced by 25 to 50 percent. The effect of hypoxia was independent of internal adenosine triphosphate and calcium. Thus, ionic conductances, and particularly the O2-sensitive potassium current, play a key role in the transduction mechanism of arterial chemoreceptors.

  7. Role of the Carotid Body in the Pathophysiology of Heart Failure

    PubMed Central

    Schultz, Harold D.; Marcus, Noah J.; Rio, Rodrigo Del

    2013-01-01

    Important recent advances implicate a role of the carotid body (CB) chemoreflex in sympathetic and breathing dysregulation in several cardio-respiratory diseases, drawing renewed interest in its potential implications for clinical treatment. Evidence from both chronic heart failure (CHF) patients and animal models indicates that the CB chemoreflex is enhanced in CHF, and contributes to the tonic elevation in sympathetic nerve activity (SNA) and periodic breathing associated with the disease. Although this maladaptive change likely derives from altered function at all levels of the reflex arc, a change in afferent function of the CB is likely to be a main driving force. This review will focus on recent advances in our understanding of the pathophysiological mechanisms that alter CB function in CHF and their potential translational impact on treatment of chronic heart failure (CHF). PMID:23824499

  8. Does Shamblin's classification predict postoperative morbidity in carotid body tumors? A proposal to modify Shamblin's classification.

    PubMed

    Luna-Ortiz, Kuauhyama; Rascon-Ortiz, Mario; Villavicencio-Valencia, Veronica; Herrera-Gomez, Angel

    2006-02-01

    The objective of this study was to analyze the possible correlation between Shamblin's classification and post-surgical morbidity in the treatment of carotid body tumors (CBTs). Seventy-two patients with carotid body tumors were seen over a 22-year period. Twenty-three patients were excluded as they did not comply with the criteria of the objectives. All patients were grouped according to Shamblin's classification. We propose a modification to this classification and make a comparison by analyzing the surgical time and bleeding, as well as the neurological and vascular damage. We resected 50 CBTs in 49 patients, ranging in age from 18 to 73 years. Three groups were formed: group I with 8 (16%) patients, group II with 17 (34%) and group III with 24 (49%). Post-surgical neurological damage was observed in one patient (12.5%) from group I, in six (35%) from group II and in nine patients (37.5%) from group III. Vascular sacrifice had to be performed in 21% of class II tumors and in 8.7% of class III. None of the class I tumors required vascular sacrifice. No statistically significant difference existed for vascular or neurological risk in relation to Shamblin's classification. However, when analyzed according to the classification proposed herein, there was a correlation between Shamblin's classification and vascular sacrifice (P =0.001). There was a statistically significant correlation between the original Shamblin and the modified Shamblin regarding surgical time and bleeding. Shamblin's classification predicts only vascular morbidity. Neurological morbidity is not reflected in it and only reflects the surgeon's experience with CBT resections. Surgical time and bleeding are directly related to the Shamblin as it reflects the size of tumors in relation to the blood vessels. Shamblin's classification must be modified to be more objective so that the international reports can accurately reflect the morbidity related to it.

  9. Changes in neurochemicals within the ventrolateral medullary respiratory column in awake goats after carotid body denervation

    PubMed Central

    Miller, Justin Robert; Neumueller, Suzanne; Muere, Clarissa; Olesiak, Samantha; Pan, Lawrence; Hodges, Matthew R.

    2013-01-01

    A current and major unanswered question is why the highly sensitive central CO2/H+ chemoreceptors do not prevent hypoventilation-induced hypercapnia following carotid body denervation (CBD). Because perturbations involving the carotid bodies affect central neuromodulator and/or neurotransmitter levels within the respiratory network, we tested the hypothesis that after CBD there is an increase in inhibitory and/or a decrease in excitatory neurochemicals within the ventrolateral medullary column (VMC) in awake goats. Microtubules for chronic use were implanted bilaterally in the VMC within or near the pre-Bötzinger Complex (preBötC) through which mock cerebrospinal fluid (mCSF) was dialyzed. Effluent mCSF was collected and analyzed for neurochemical content. The goats hypoventilated (peak +22.3 ± 3.4 mmHg PaCO2) and exhibited a reduced CO2 chemoreflex (nadir, 34.8 ± 7.4% of control ΔV̇E/ΔPaCO2) after CBD with significant but limited recovery over 30 days post-CBD. After CBD, GABA and glycine were above pre-CBD levels (266 ± 29% and 189 ± 25% of pre-CBD; P < 0.05), and glutamine and dopamine were significantly below pre-CBD levels (P < 0.05). Serotonin, substance P, and epinephrine were variable but not significantly (P > 0.05) different from control after CBD. Analyses of brainstem tissues collected 30 days after CBD exhibited 1) a midline raphe-specific reduction (P < 0.05) in the percentage of tryptophan hydroxylase–expressing neurons, and 2) a reduction (P < 0.05) in serotonin transporter density in five medullary respiratory nuclei. We conclude that after CBD, an increase in inhibitory neurotransmitters and a decrease in excitatory neuromodulation within the VMC/preBötC likely contribute to the hypoventilation and attenuated ventilatory CO2 chemoreflex. PMID:23869058

  10. AMP-ACTIVATED PROTEIN KINASE MEDIATES CAROTID BODY EXCITATION BY HYPOXIA*

    PubMed Central

    Wyatt, Christopher N.; Mustard, Kirsty J.W.; Pearson, Selina A.; Dallas, Mark L; Atkinson, Lucy; Kumar, Prem; Peers, Chris; Hardie, D. Grahame; Evans, A. Mark

    2007-01-01

    Early detection of an O2 deficit in the bloodstream is essential to initiate corrective changes in the breathing pattern of mammals. Carotid bodies serve an essential role in this respect;their type I cells depolarize when O2 levels fall, causing voltage-gated Ca2+ entry. Subsequent neurosecretion elicits increased afferent chemosensory fibre discharge to induce appropriate changes in respiratory function (1). Whilst depolarization of type I cells by hypoxia is known to arise from K+ channel inhibition, the identity of the signalling pathway has been contested and the coupling mechanism is unknown (2). We tested the hypothesis that AMP-activated protein kinase (AMPK)1 is the effector of hypoxic chemotransduction. AMPK is co-localized at the plasma membrane of type I cells with O2-sensitive K+ channels. In isolated type I cells, activation of AMPK using AICAR inhibited O2-sensitive K+ currents (carried by large conductance Ca2+-activated (BKCa) channels and TASK-like channels), leading to plasma membrane depolarization, Ca2+ influx and increased chemosensory fibre discharge. Conversely, the AMPK antagonist compound C reversed the effects of hypoxia and AICAR on type I cell and carotid body activation. These results suggest that AMPK activation is both sufficient and necessary for the effects of hypoxia. Furthermore, AMPK activation inhibited currents carried by recombinant BKCa channels while purified AMPK phosphorylated the α subunit of the channel in immunoprecipitates, an effect that was stimulated by AMP and inhibited by compound C. Our findings demonstrate a central role for AMPK in stimulus-response coupling by hypoxia, and identify for the first time a link between metabolic stress and ion channel regulation in an O2-sensing system. PMID:17179156

  11. Effects of osmotic changes on the chemoreceptor cell of rat carotid body.

    PubMed

    Molnár, Zoltán; Petheo, Gábor L; Fülöp, Csaba; Spät, András

    2003-01-15

    The carotid body plays a crucial role in cardiorespiratory regulation. In the present study we investigated the effect of osmotic changes on cytoplasmic calcium concentration ([Ca(2+)](c)) and pH (pH(i)) of isolated chemoreceptor cells of the rat carotid body. In CO(2)/HCO(3)(-)-buffered medium, reduction of osmolality from the control level of 300 mosmol kg(-1) to 250-285 mosmol kg(-1) resulted in a rise in [Ca(2+)](c), as measured with Indo-1, whereas elevation of osmolality to 350 mosmol kg(-1) had no effect. The Ca(2+) response required extracellular Ca(2+) and was reduced by application of the L-type Ca(2+) channel antagonist nifedipine (10 microM). The hyposmosis-induced Ca(2+) response could be prevented by application of niflumic acid (300 microM), an inhibitor of the swelling-activated Cl(-) channel. In whole-cell patch-clamp experiments niflumic acid abolished the swelling-activated Cl(-) current but only slightly depressed the Ca(2+) current. The inhibition of Ca(2+) current by niflumic acid does not account for its action in preventing of hyposmosis-induced Ca(2+) response, which seems to be initiated by Cl(-)-mediated depolarisation. Withdrawal of CO(2)/HCO(3)(-) also prevented the Ca(2+) response. Reduction of the osmotic concentration by 50 mosmol kg(-1) induced a small but sustained decrease in pH(i), while elevation by 50 mosmol kg(-1) had an inverse effect, as measured fluorimetrically with carboxy SNARF-1. Our conclusion is that in the rat chemoreceptor cell the activation of Cl(-) channels, e.g. by hyposmotic challenge, induces depolarisation, which, in turn, activates voltage-gated Ca(2+) channels.

  12. The Effects of Preoperative Embolization on Carotid Body Paraganglioma Surgery: A Systematic Review and Meta-analysis.

    PubMed

    Jackson, Ryan S; Myhill, Jeffrey A; Padhya, Tapan A; McCaffrey, Judith C; McCaffrey, Thomas V; Mhaskar, Rahul S

    2015-12-01

    There is no definitive consensus on the impact of preoperative embolization on carotid body paraganglioma management. The purpose of this study was to assess the effects of preoperative embolization on carotid body paraganglioma excision. A systematic search was conducted without limits, and it included studies published on or before July 2013 from PubMed, CINAHL, Web of Knowledge, and the Cochrane Library. Relevant synonyms for the search terms "paraganglioma,"carotid body tumor," and "embolization" were applied. Studies evaluating patients undergoing surgical intervention with embolization for carotid body tumors were included. Two reviewers independently assessed the titles and abstracts for inclusion and extracted the data. The guidelines set forth by the Cochrane Collaboration were followed in the process of data extraction. Data were pooled with a fixed effects model, and standardized mean difference (SMD) and 95% confidence intervals (95% CIs) are reported. A total of 22 studies (15 nonrandomized studies with a comparator, 7 single-arm studies) were included, enrolling 578 patients with 607 tumors. Patients undergoing preoperative embolization had significantly less estimated blood loss compared with those of surgical excision only (12 studies; 295 tumors; SMD: -0.52; 95% CI: -0.77, -0.28). Patients undergoing preoperative embolization had less operative time compared with that of surgical excision only (6 studies; 174 tumors; SMD: -0.46; 95% CI: -0.77, -0.14). Surgical excision with preoperative embolization appears to decrease estimated blood loss and operative time when compared with that without preoperative embolization for carotid body paragangliomas. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

  13. KISS1 and KISS1R expression in the human and rat carotid body and superior cervical ganglion.

    PubMed

    Porzionato, A; Fenu, G; Rucinski, M; Macchi, V; Montella, A; Malendowicz, L K; De Caro, R

    2011-05-04

    KISS1 and its receptor, KISS1R, have both been found to be expressed in central nervous system, but few data are present in the literature about their distribution in peripheral nervous structures. Thus, the aim of the present study was to investigate, through immunohistochemistry, the expression and distribution of KISS1 and KISS1R in the rat and human carotid bodies and superior cervical ganglia, also with particular reference to the different cellular populations. Materials consisted of carotid bodies and superior cervical ganglia were obtained at autopsy from 10 adult subjects and sampled from 10 adult Sprague-Dawley rats. Immunohistochemistry revealed diffuse expression of KISS1 and KISS1R in type I cells of both human and rat carotid bodies, whereas type II cells were negative. In both human and rat superior cervical ganglia positive anti-KISS1 and -KISS1R immunostainings were also selectively found in ganglion cells, satellite cells being negative. Endothelial cells also showed moderate immunostaining for both KISS1 and KISS1R. The expression of both kisspeptins and kisspeptin receptors in glomic type I cells and sympathetic ganglion cells supports a modulatory role of KISS1 on peripheral chemoreception and sympathetic function. Moreover, local changes in blood flow have been considered to be involved in carotid body chemoreceptor discharge and kisspeptins and kisspeptin receptors have also been found in the endothelial cells. As a consequence, a possible role of kisspeptins in the regulation of carotid body blood flow and, indirectly, in chemoreceptor discharge may also be hypothesized.

  14. Dosing obese cats based on body weight spuriously affects some measures of glucose tolerance.

    PubMed

    Reeve-Johnson, M K; Rand, J S; Anderson, S T; Appleton, D J; Morton, J M; Vankan, D

    2016-10-01

    The primary objective was to investigate whether dosing glucose by body weight results in spurious effects on measures of glucose tolerance in obese cats because volume of distribution does not increase linearly with body weight. Healthy research cats (n = 16; 6 castrated males, 10 spayed females) were used. A retrospective study was performed using glucose concentration data from glucose tolerance and insulin sensitivity tests before and after cats were fed ad libitum for 9 to 12 mo to promote weight gain. The higher dose of glucose (0.5 vs 0.3 g/kg body weight) in the glucose tolerance tests increased 2-min glucose concentrations (P < 0.001), and there was a positive correlation between 2-min and 2-h glucose (r = 0.65, P = 0.006). Two-min (P = 0.016 and 0.019, respectively), and 2-h (P = 0.057 and 0.003, respectively) glucose concentrations, and glucose half-life (T1/2; P = 0.034 and <0.001 respectively) were positively associated with body weight and body condition score. Glucose dose should be decreased by 0.05 g for every kg above ideal body weight. Alternatively, for every unit of body condition score above 5 on a 9-point scale, observed 2-h glucose concentration should be adjusted down by 0.1 mmol/L. Dosing glucose based on body weight spuriously increases glucose concentrations at 2 h in obese cats and could lead to cats being incorrectly classified as having impaired glucose tolerance. This has important implications for clinical studies assessing the effect of interventions on glucose tolerance when lean and obese cats are compared.

  15. Overt and subclinical baroreflex dysfunction following bilateral carotid body tumor resection: pathophysiology, diagnosis, and implications for management.

    PubMed

    Ghali, Michael G Z; Srinivasan, Visish M; Hanna, Ehab; DeMonte, Franco

    2017-02-25

    Carotid body paragangliomas are rare, usually benign, tumors arising from glomus cells of the carotid body. Bilateral involvement is present in ∼5% of sporadic cases and up to one-third of familial cases. In the majority of patients undergoing bilateral resection of carotid body tumors (CBTs), a condition known as baroreflex failure syndrome (BFS) develops following resection of the second tumor characterized by headache, anxiety, emotional lability, orthostatic lightheadedness, hypertension, and tachycardia. This is believed to result from damage to the carotid baroreceptor apparatus. Patients without overt cardiovascular abnormalities may have subclinical baroreceptor dysfunction evident only on specific testing, measuring HR and sympathetic nerve responses to baro-loading (eg., phenylephrine) and baro-unloading (e.g., Valsalva maneuver). Given the high incidence of BFS in patients undergoing bilateral resection of CBTs, it is suggested that operation be limited to unilateral resection of the dominant/symptomatic lesion and non-surgical intervention (i.e., embolization, radiotherapy) on the contralateral side. Alternatively, refinement of surgical technique to prevent injury to elements of the baroreceptor apparatus may prevent this unfortunate complication of bilateral tumor resection. We present a case of a 16 year old girl with bilateral jugular vagale and carotid body tumors who developed hypertension following surgical resection of her left jugular vagale tumor and worsening of hypertension concurrent with progression, eventually requiring intensity-modulated radiation therapy and a resection for significant progression of her left jugular vagale tumor. Our case illustrates the generalizability of BFS to patients with tumors involving the vagal baro-afferent fibers.

  16. The role of nitric oxide in carotid chemoreception.

    PubMed

    Wang, Z Z; Dinger, B G; Stensaas, L J; Fidone, S J

    1995-01-01

    Immunocytochemical and histochemical studies of cat and rat carotid bodies have revealed a plexus of nitric oxide synthase (NOS)-positive nerve fibers associated with lobules of chemosensory type I cells as well as with the carotid body vasculature. NOS-positive fibers originate from (1) autonomic neurons located in the carotid body and distributed along the carotid sinus nerve (CNS) and IXth cranial nerve which terminate in the adventitial layer of carotid body blood vessels, and (2) from unipolar sensory neurons of the petrosal (IXth nerve) ganglion. Carotid bodies incubated with the NO precursor, 3H-arginine, yield 3H-citrulline, the detectable coproduct of NO synthesis. Furthermore, electrical stimulation of the CNS or exposure of carotid bodies to hypoxic incubation media elevates 3H-citrulline formation. Millimolar concentrations of L-arginine inhibit chemoreceptor activity evoked by hypoxia, an effect which is reversed by the specific NOS antagonist, L-NG-nitroarginine methylester (L-NAME, 0.1 mM). Electrical stimulation of CNS C fibers elevates cyclic GMP in the carotid body vasculature and lobules of type I cells. Cyclic GMP production is reduced during stimulation in the presence of L-NAME, a finding consistent with the known ability of NO to activate a soluble form of guanylate cyclase. Further studies showed that brief (< 1 min) stimulation of CNS C fibers inhibits basal chemoreceptor discharge in a perfused/superfused in vitro carotid body preparation, whereas prolonged (> 5 min) stimulation is required to inhibit the response to hypoxia. The inhibitory effect is reversed by L-NAME. Our combined anatomical, neuropharmacological and electrophysiological data suggest that NO plays a dual role in mediating CNS inhibition, one via its actions on the organ's vasculature and the other through direct effects on the chemosensory type I cells. The former pathway involves cholinergic/NOS presumptive parasympathetic autonomic neurons, while the latter may be

  17. Influence of age, body mass index, and blood pressure on the carotid intima-media thickness in normotensive and hypertensive patients.

    PubMed

    Honzikova, Natasa; Labrova, Ruzena; Fiser, Bohumil; Maderova, Eva; Novakova, Zuzana; Zavodna, Eva; Semrad, Borivoj

    2006-10-01

    We investigated whether body mass index and blood pressure have an additive influence on the carotid intima-media thickness (IMT). In 27 patients treated for hypertension (47.2+/-8.7 years) and 23 normotensive subjects (44.1+/-8.1 years), 24-h recording of blood pressure was performed. The carotid IMT was determined by ultrasonography and baroreflex sensitivity by a spectral method from 5-min recordings of blood pressure. Significant differences between hypertensive and normotensive subjects were observed for carotid IMT (0.60+/-0.08 vs. 0.51+/-0.07 mm; p<0.001) and baroreflex sensitivity (3.5+/-1.8 vs. 5.6+/-2.1 ms/mm Hg; p<0.001). Hierarchical multiple regression analysis (p<0.01) showed that carotid IMT was positively correlated with age (p<0.001) and body mass index (p<0.05) in normotensive subjects. The increased carotid IMT in hypertensive patients was not additively influenced by either age or body mass index. Baroreflex sensitivity decreased with age (p<0.01) and with carotid IMT (p<0.05) in normotensive subjects only. Multiregression analysis showed that an additive influence of age and body mass index on the development of carotid IMT is essential only in normotensive subjects. In hypertensive subjects the influence of blood pressure predominates, as documented by a comparison of the carotid IMT between hypertensive and normotensive subjects.

  18. Carotid body denervation improves autonomic and cardiac function and attenuates disordered breathing in congestive heart failure

    PubMed Central

    Marcus, Noah J; Rio, Rodrigo; Schultz, Evan P; Xia, Xiao-Hong; Schultz, Harold D

    2014-01-01

    In congestive heart failure (CHF), carotid body (CB) chemoreceptor activity is enhanced and is associated with oscillatory (Cheyne–Stokes) breathing patterns, increased sympathetic nerve activity (SNA) and increased arrhythmia incidence. We hypothesized that denervation of the CB (CBD) chemoreceptors would reduce SNA, reduce apnoea and arrhythmia incidence and improve ventricular function in pacing-induced CHF rabbits. Resting breathing, renal SNA (RSNA) and arrhythmia incidence were measured in three groups of animals: (1) sham CHF/sham–CBD (sham–sham); (2) CHF/sham–CBD (CHF–sham); and (3) CHF/CBD (CHF–CBD). Chemoreflex sensitivity was measured as the RSNA and minute ventilatory () responses to hypoxia and hypercapnia. Respiratory pattern was measured by plethysmography and quantified by an apnoea–hypopnoea index, respiratory rate variability index and the coefficient of variation of tidal volume. Sympatho-respiratory coupling (SRC) was assessed using power spectral analysis and the magnitude of the peak coherence function between tidal volume and RSNA frequency spectra. Arrhythmia incidence and low frequency/high frequency ratio of heart rate variability were assessed using ECG and blood pressure waveforms, respectively. RSNA and responses to hypoxia were augmented in CHF–sham and abolished in CHF–CBD animals. Resting RSNA was greater in CHF–sham compared to sham–sham animals (43 ± 5% max vs. 23 ± 2% max, P < 0.05), and this increase was not found in CHF–CBD animals (25 ± 1% max, P < 0.05 vs. CHF–sham). Low frequency/high frequency heart rate variability ratio was similarly increased in CHF and reduced by CBD (P < 0.05). Respiratory rate variability index, coefficient of variation of tidal volume and apnoea–hypopnoea index were increased in CHF–sham animals and reduced in CHF–CBD animals (P < 0.05). SRC (peak coherence) was increased in CHF–sham animals (sham–sham 0.49 ± 0.05; CHF–sham 0.79

  19. Blood donation, body iron status and carotid intima-media thickness.

    PubMed

    Engberink, Mariëlle F; Geleijnse, Johanna M; Durga, Jane; Swinkels, Dorine W; de Kort, Wim L A M; Schouten, Evert G; Verhoef, Petra

    2008-02-01

    Iron could promote free radical formation, which may lead to injury of the arterial wall and atherosclerosis. Blood donation may reduce cardiovascular risk by lowering body iron status. We collected data on blood donation history and intima-media thickness of the common carotid artery (CIMT) in 819 subjects (50-70 years), who were recruited from municipal and blood bank registries in The Netherlands. Serum iron parameters were assessed, including non-transferrin bound iron (NTBI) that has recently been found in conditions of iron overload. Serum ferritin was lower in current donors (n=443; 44 microg/L) than in ex-donors (n=120; 114 microg/L) and never-donors (n=256; 124 microg/L, P for trend <0.001). For NTBI, values were 2.33, 2.54, and 2.51 micromol/L, respectively (P<0.05). CIMT was slightly reduced in frequent donors (i.e., > or =49 times during life or > or =2 times per year), although not statistically significant. CIMT was not significantly related to NTBI. Frequent blood donation, resulting in lowered body iron, might give some protection against accelerated atherosclerosis.

  20. Imaging carotid body chemodectomas with 68Ga-DOTA-NOC PET-CT

    PubMed Central

    Naswa, N; Kumar, A; Sharma, P; Bal, C; Malhotra, A; Kumar, R

    2012-01-01

    Objective The purpose of the present study was to evaluate the role of 68-gallium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-1-Nal3-octreotide (68Ga-DOTA-NOC) positron emission tomography CT (PET-CT) in carotid body chemodectomas (CBCs). Methods : 5 patients with known CBCs (conventional imaging and angiography) were evaluated retrospectively (3 males, 2 females; mean age 36.6 years). All underwent PET-CT after injection of 148 MBq (4 mCi) of 68Ga-DOTA-NOC. Results : At baseline there were four bilateral CBCs and one unilateral CBC with an additional glomus tympanicum and bilateral glomus jugulare tumour in these five patients. All these lesions showed intense uptake on 68Ga-DOTA-NOC PET-CT. Apart from these known lesions, additional tumours were detected in three patients; glomus jugulare in one, aortic body tumour and multiple abdominal paragangliomas in another and unsuspected vertebral metastasis in the last. Overall it led to a change in management in 3 of the 5 patients (60%). Conclusion : 68Ga-DOTA-NOC PET-CT is a promising non-invasive imaging modality in the detection and characterisation of CBCs. PMID:22096221

  1. Oxygen sensing by the carotid body: mechanisms and role in adaptation to hypoxia.

    PubMed

    López-Barneo, José; González-Rodríguez, Patricia; Gao, Lin; Fernández-Agüera, M Carmen; Pardal, Ricardo; Ortega-Sáenz, Patricia

    2016-04-15

    Oxygen (O2) is fundamental for cell and whole-body homeostasis. Our understanding of the adaptive processes that take place in response to a lack of O2(hypoxia) has progressed significantly in recent years. The carotid body (CB) is the main arterial chemoreceptor that mediates the acute cardiorespiratory reflexes (hyperventilation and sympathetic activation) triggered by hypoxia. The CB is composed of clusters of cells (glomeruli) in close contact with blood vessels and nerve fibers. Glomus cells, the O2-sensitive elements in the CB, are neuron-like cells that contain O2-sensitive K(+)channels, which are inhibited by hypoxia. This leads to cell depolarization, Ca(2+)entry, and the release of transmitters to activate sensory fibers terminating at the respiratory center. The mechanism whereby O2modulates K(+)channels has remained elusive, although several appealing hypotheses have been postulated. Recent data suggest that mitochondria complex I signaling to membrane K(+)channels plays a fundamental role in acute O2sensing. CB activation during exposure to low Po2is also necessary for acclimatization to chronic hypoxia. CB growth during sustained hypoxia depends on the activation of a resident population of stem cells, which are also activated by transmitters released from the O2-sensitive glomus cells. These advances should foster further studies on the role of CB dysfunction in the pathogenesis of highly prevalent human diseases. Copyright © 2016 the American Physiological Society.

  2. Selective accumulation of biotin in arterial chemoreceptors: requirement for carotid body exocytotic dopamine secretion.

    PubMed

    Ortega-Sáenz, Patricia; Macías, David; Levitsky, Konstantin L; Rodríguez-Gómez, José A; González-Rodríguez, Patricia; Bonilla-Henao, Victoria; Arias-Mayenco, Ignacio; López-Barneo, José

    2016-12-15

    Biotin, a vitamin whose main role is as a coenzyme for carboxylases, accumulates at unusually large amounts within cells of the carotid body (CB). In biotin-deficient rats biotin rapidly disappears from the blood; however, it remains at relatively high levels in CB glomus cells. The CB contains high levels of mRNA for SLC5a6, a biotin transporter, and SLC19a3, a thiamine transporter regulated by biotin. Animals with biotin deficiency exhibit pronounced metabolic lactic acidosis. Remarkably, glomus cells from these animals have normal electrical and neurochemical properties. However, they show a marked decrease in the size of quantal dopaminergic secretory events. Inhibitors of the vesicular monoamine transporter 2 (VMAT2) mimic the effect of biotin deficiency. In biotin-deficient animals, VMAT2 protein expression decreases in parallel with biotin depletion in CB cells. These data suggest that dopamine transport and/or storage in small secretory granules in glomus cells depend on biotin. Biotin is a water-soluble vitamin required for the function of carboxylases as well as for the regulation of gene expression. Here, we report that biotin accumulates in unusually large amounts in cells of arterial chemoreceptors, carotid body (CB) and adrenal medulla (AM). We show in a biotin-deficient rat model that the vitamin rapidly disappears from the blood and other tissues (including the AM), while remaining at relatively high levels in the CB. We have also observed that, in comparison with other peripheral neural tissues, CB cells contain high levels of SLC5a6, a biotin transporter, and SLC19a3, a thiamine transporter regulated by biotin. Biotin-deficient rats show a syndrome characterized by marked weight loss, metabolic lactic acidosis, aciduria and accelerated breathing with normal responsiveness to hypoxia. Remarkably, CB cells from biotin-deficient animals have normal electrophysiological and neurochemical (ATP levels and catecholamine synthesis) properties; however

  3. Whole body mechanics of stealthy walking in cats.

    PubMed

    Bishop, Kristin L; Pai, Anita K; Schmitt, Daniel

    2008-01-01

    The metabolic cost associated with locomotion represents a significant part of an animal's metabolic energy budget. Therefore understanding the ways in which animals manage the energy required for locomotion by controlling muscular effort is critical to understanding limb design and the evolution of locomotor behavior. The assumption that energetic economy is the most important target of natural selection underlies many analyses of steady animal locomotion, leading to the prediction that animals will choose gaits and postures that maximize energetic efficiency. Many quadrupedal animals, particularly those that specialize in long distance steady locomotion, do in fact reduce the muscular contribution required for walking by adopting pendulum-like center of mass movements that facilitate exchange between kinetic energy (KE) and potential energy (PE). However, animals that are not specialized for long distance steady locomotion may face a more complex set of requirements, some of which may conflict with the efficient exchange of mechanical energy. For example, the "stealthy" walking style of cats may demand slow movements performed with the center of mass close to the ground. Force plate and video data show that domestic cats (Felis catus, Linnaeus, 1758) have lower mechanical energy recovery than mammals specialized for distance. A strong negative correlation was found between mechanical energy recovery and diagonality in the footfalls and there was also a negative correlation between limb compression and diagonality of footfalls such that more crouched postures tended to have greater diagonality. These data show a previously unrecognized mechanical relationship in which crouched postures are associated with changes in footfall pattern which are in turn related to reduced mechanical energy recovery. Low energy recovery was not associated with decreased vertical oscillations of the center of mass as theoretically predicted, but rather with posture and footfall pattern

  4. Lynxacarus radovskyi mites in feral cats: a study of diagnostic methods, preferential body locations, co-infestations and prevalence.

    PubMed

    Ketzis, Jennifer K; Dundas, James; Shell, Linda G

    2016-10-01

    Lynxacarus radovskyi (fur mites) are ectoparasites found on the hair shafts of cats living in tropical environments. Diagnosis is via microscopic examination of hairs. Various anatomical areas have been reported to harbour these mites. To assess adhesive tape impressions and trichograms for detecting L. radovskyi and co-infestations; to determine host body predilection sites and affected gender; to determine prevalence of L. radovskyi in a feral cat population. 121 feral cats in a trap, neuter and release programme. After cats were premedicated for surgical sterilization, hairs from seven to nine body sites were removed from each cat using adhesive tape impression and trichogram techniques. Samples were examined at 10-100× magnification using compound or stereo microscopes. The prevalence of L. radovskyi was 71% (86 of 121) within the feral cat population. Tape impressions identified 75 cats; trichograms identified 56 cats. There were fewer false negative results with tape impressions. Caudal body sites were more likely to be positive, with the perianal area being the most commonly affected. Males and females were infested equally. Tape impressions identified more Cheyletiella blakei infestations and both methods identified some Felicola felis infestations. Tape impressions were easier to perform and identified more L. radovskyi positive cats and more co-infestations. Hairs from the perianal area and other caudal body sites are most likely to harbour L. radovskyi. Within this feral cat population, L. radovskyi was a common infestation. © 2016 ESVD and ACVD.

  5. Management of dogs and cats with endotracheal tube tracheal foreign bodies

    PubMed Central

    Nutt, Laura K.; Webb, Jinelle A.; Prosser, Kirsten J.; Defarges, Alice

    2014-01-01

    Two cats and 3 dogs were treated for an endotracheal tube tracheal foreign body (ETFB) during recovery from general anesthesia. Bronchoscopy was used to remove the ETFB. Animals were clinically normal at discharge. While rare, ETFB can occur upon recovery from anesthesia. Bronchoscopy is an effective way to remove ETFB. PMID:24891640

  6. Variations in leopard cat (Prionailurus bengalensis) skull morphology and body size: sexual and geographic influences

    PubMed Central

    Oliveira, Luiz Flamarion B.

    2015-01-01

    The leopard cat, Prionailurus bengalensis (Kerr, 1792), is one of the most widespread Asian cats, occurring in continental eastern and southeastern Asia. Since 1929, several studies have focused on the morphology, ecology, and taxonomy of leopard cats. Nevertheless, hitherto there has been no agreement on basic aspects of leopard cat biology, such as the presence or absence of sexual dimorphism, morphological skull and body differences between the eleven recognized subspecies, and the biogeography of the different morphotypes. Twenty measurements on 25 adult leopard cat skulls from different Asian localities were analyzed through univariate and multivariate statistical approaches. Skull and external body measurements from studies over the last 77 years were assembled and organized in two categories: full data and summary data. Most of this database comprises small samples, which have never been statistically tested and compared with each other. Full data sets were tested with univariate and multivariate statistical analyses; summary data sets (i.e., means, SDs, and ranges) were analyzed through suitable univariate approaches. The independent analyses of the data from these works confirmed our original results and improved the overview of sexual dimorphism and geographical morphological variation among subspecies. Continental leopard cats have larger skulls and body dimensions. Skulls of Indochinese morphotypes have broader and higher features than those of continental morphotypes, while individuals from the Sunda Islands have skulls with comparatively narrow and low profiles. Cranial sexual dimorphism is present in different degrees among subspecies. Most display subtle sex-related variations in a few skull features. However, in some cases, sexual dimorphism in skull morphology is absent, such as in P. b. sumatranus and P. b. borneoensis. External body measurement comparisons also indicate the low degree of sexual dimorphism. Apart from the gonads, the longer hind

  7. Variations in leopard cat (Prionailurus bengalensis) skull morphology and body size: sexual and geographic influences.

    PubMed

    Sicuro, Fernando L; Oliveira, Luiz Flamarion B

    2015-01-01

    The leopard cat, Prionailurus bengalensis (Kerr, 1792), is one of the most widespread Asian cats, occurring in continental eastern and southeastern Asia. Since 1929, several studies have focused on the morphology, ecology, and taxonomy of leopard cats. Nevertheless, hitherto there has been no agreement on basic aspects of leopard cat biology, such as the presence or absence of sexual dimorphism, morphological skull and body differences between the eleven recognized subspecies, and the biogeography of the different morphotypes. Twenty measurements on 25 adult leopard cat skulls from different Asian localities were analyzed through univariate and multivariate statistical approaches. Skull and external body measurements from studies over the last 77 years were assembled and organized in two categories: full data and summary data. Most of this database comprises small samples, which have never been statistically tested and compared with each other. Full data sets were tested with univariate and multivariate statistical analyses; summary data sets (i.e., means, SDs, and ranges) were analyzed through suitable univariate approaches. The independent analyses of the data from these works confirmed our original results and improved the overview of sexual dimorphism and geographical morphological variation among subspecies. Continental leopard cats have larger skulls and body dimensions. Skulls of Indochinese morphotypes have broader and higher features than those of continental morphotypes, while individuals from the Sunda Islands have skulls with comparatively narrow and low profiles. Cranial sexual dimorphism is present in different degrees among subspecies. Most display subtle sex-related variations in a few skull features. However, in some cases, sexual dimorphism in skull morphology is absent, such as in P. b. sumatranus and P. b. borneoensis. External body measurement comparisons also indicate the low degree of sexual dimorphism. Apart from the gonads, the longer hind

  8. Effect of hyperoxic exposure during early development on neurotrophin expression in the carotid body and nucleus tractus solitarii

    PubMed Central

    Chavez-Valdez, Raul; Mason, Ariel; Nunes, Ana R.; Northington, Frances J.; Tankersley, Clarke; Ahlawat, Rajni; Johnson, Sheree M.

    2012-01-01

    Synaptic activity can modify expression of neurotrophins, which influence the development of neuronal circuits. In the newborn rat, early hyperoxia silences the synaptic activity and input from the carotid body, impairing the development and function of chemoreceptors. The purpose of this study was to determine whether early hyperoxic exposure, sufficient to induce hypoplasia of the carotid body and decrease the number of chemoafferents, would also modify neurotrophin expression within the nucleus tractus solitarii (nTS). Rat pups were exposed to hyperoxia (fraction of inspired oxygen 0.60) or normoxia until 7 or 14 days of postnatal development (PND). In the carotid body, hyperoxia decreased brain-derived neurotrophic factor (BDNF) protein expression by 93% (P = 0.04) after a 7-day exposure, followed by a decrease in retrogradely labeled chemoafferents by 55% (P = 0.004) within the petrosal ganglion at 14 days. Return to normoxia for 1 wk after a 14-day hyperoxic exposure did not reverse this effect. In the nTS, hyperoxia for 7 days: 1) decreased BDNF gene expression by 67% and protein expression by 18%; 2) attenuated upregulation of BDNF mRNA levels in response to acute hypoxia; and 3) upregulated p75 neurotrophic receptor, truncated tropomyosin kinase B (inactive receptor), and cleaved caspase-3. These effects were not observed in the locus coeruleus (LC). Hyperoxia for 14 days also decreased tyrosine hydroxylase levels by 18% (P = 0.04) in nTS but not in the LC. In conclusion, hyperoxic exposure during early PND reduces neurotrophin levels in the carotid body and the nTS and shifts the balance of neurotrophic support from prosurvival to proapoptotic in the nTS, the primary brain stem site for central integration of sensory and autonomic inputs. PMID:22422797

  9. The carotid body in the duck and the consequences of its denervation upon the cardiac responses to immersion

    PubMed Central

    Jones, D. R.; Purves, M. J.

    1970-01-01

    1. The anatomy of the carotid body and its afferent nerve supply was studied in the duck and a method of denervating the carotid body which ensures a satisfactory post-operative course is described. 2. The effect of denervating the carotid body upon the cardiac response to immersion of the head in water was studied in ten ducks which at the time of the test were unanaesthetized. 3. When the nerves were intact, immersion of the head caused a fall in heart rate after a latent period of between 1 and 9 sec to an average of 24% of the resting rate after 30 sec. Simultaneous measurement of arterial oxygen tension (Pa, O2) in the brachiocephalic artery showed a rapid initial fall during the initial 10 sec from control levels, 93-103 mm Hg, to between 42 and 47 mm Hg, followed by a gradual fall of 3-5 mm Hg for each subsequent 30 sec period of submergence. 4. Following carotid body denervation, the latent period before heart rate started to fall was no different from control but the average fall in heart rate was now to 90% of the resting rate and brachiocephalic Pa. O2 continued to fall steadily during submergence reaching levels of between 10 and 21 mm Hg by the end of the second minute. 5. Stimulation of the central end of branches of the IXth (glossopharyngeal) nerve supplying the glottis caused apnoea and bradycardia. 6. It is concluded that apnoea and bradycardia during submergence in the duck is initiated reflexly from receptors in the nares, pharynx and glottis but that the profound degree of bradycardia and mechanisms which maintain a relatively high Pa, O2 are regulated by peripheral chemoreceptor activity. ImagesPlate 1 PMID:5501002

  10. Research Report: Intermittent hypobaric hypoxia and hyperbaric oxygen on GAP-43 in the rat carotid body.

    PubMed

    Peng, Zhengwu; Fan, Juan; Liu, Ling; Kuang, Fang; Xue, Fen; Wang, Bairen

    2015-01-01

    Adaptive changes in the carotid body (CB) including the expression of the growth-associated protein-43 (GAP-43) have been studied in response to low, but not high, oxygen exposure. Expression of GAP-43 in the CB of rats under different atmospheric pressures and oxygen partial pressure (PO2) conditions was investigated. Mature male Sprague-Dawley rats were exposed to intermittent hypobaric hypoxia (IHH, 0, 1, 2 and 3 weeks), intermittent hyperbaric oxygen (IHBO2, 0, 1, 5 and 10 days, sacrificed six hours or 24 hours after the last HBO2 exposure), and intermittent hyperbaric normoxia (IHN, same treatment pattern as IHBO2). GAP-43 was highly expressed (mainly in type I cells) in the CB of normal rats. IHH u-regulated GAP-43 expression in the CB with significant differences (immunohistochemical staining [IHC]: F(3,15)=40.64, P < 0.01; western blot [WB]: F(3,16) = 53.52, P < 0.01) across the subgroups. GAP-43 expression in the CB was inhibited by IHBO2 (controls vs. IHBO2 groups, IHC: F(6,30) = 15.85, P < 0.01; WB: F(6,29) = 15.95, P < 0.01). No detectable changes in GAP-43 expression were found for IHN. These findings indicated that different PO2 conditions, but not air pressures, played an important role in the plasticity of the CB, and that GAP-43 might be a viable factor for the plasticity of the CB.

  11. Central role of carotid body chemoreceptors in disordered breathing and cardiorenal dysfunction in chronic heart failure

    PubMed Central

    Marcus, Noah J.; Del Rio, Rodrigo; Schultz, Harold D.

    2014-01-01

    Oscillatory breathing (OB) patterns are observed in pre-term infants, patients with cardio-renal impairment, and in otherwise healthy humans exposed to high altitude. Enhanced carotid body (CB) chemoreflex sensitivity is common to all of these populations and is thought to contribute to these abnormal patterns by destabilizing the respiratory control system. OB patterns in chronic heart failure (CHF) patients are associated with greater levels of tonic and chemoreflex-evoked sympathetic nerve activity (SNA), which is associated with greater morbidity and poor prognosis. Enhanced chemoreflex drive may contribute to tonic elevations in SNA by strengthening the relationship between respiratory and sympathetic neural outflow. Elimination of CB afferents in experimental models of CHF has been shown to reduce OB, respiratory-sympathetic coupling, and renal SNA, and to improve autonomic balance in the heart. The CB chemoreceptors may play an important role in progression of CHF by contributing to respiratory instability and OB, which in turn further exacerbates tonic and chemoreflex-evoked increases in SNA to the heart and kidney. PMID:25505417

  12. Effects of almitrine on the release of catecholamines from the rabbit carotid body in vitro.

    PubMed

    Almaraz, L; Rigual, R; Obeso, A; Evrard, Y; Gonzalez, C

    1992-07-01

    1. Almitrine increases ventilation by stimulating the carotid body (CB) arterial chemoreceptors but neither its intraglomic target nor its mechanism of action have been elucidated. 2. We have tested the hypothesis that chemoreceptor cells are targets for almitrine by studying its effects on the release of 3H-catecholamines in an in vitro rabbit CB preparation. 3. It was found that almitrine (0.3 and 1.5 x 10(-6) M; i.e. 0.2 and 1 mg ml-1) increases the resting release of 3H-catecholamines from CBs (previously loaded with [3H]-tyrosine) incubated in a balanced 95% O2/5% CO2-equilibrated solution. 4. Almitrine at a concentration of 3 x 10(-6) M (2 mg l-1) also augmented the release of 3H-catecholamines elicited by incubating the CBs in a hypoxic solution (equilibrated with 7% O2/5% CO2 in N2), by high external K+ (35 mM) and by veratridine (2 x 10(-5) M), but did not modify release induced by dinitrophenol (7.5 x 10(-5) M). 5. At the same concentration (3 x 10(-6) M), almitrine increased the rate of dopamine synthesis and was ineffective in modifying the cyclic AMP levels in either normoxic or hypoxic CBs. 6. It is concluded that chemoreceptor cells are the intraglomic targets for almitrine. The mechanisms of action of almitrine on chemoreceptor cells are discussed.

  13. Carotid body: a new target for rescuing neural control of cardiorespiratory balance in disease.

    PubMed

    Fitzgerald, Robert S

    2014-01-01

    Significant insight into the mechanisms involved in chronic heart failure (CHF) have been provided by Schultz and his associates at the University of Nebraska Medical Center with the use of pacing-induced heart failure rabbits. Critical among the CHF mechanisms was the role of the carotid body (CB). The stimulated CB produces a wide array of systemic reflex responses; certainly those in the cardiopulmonary (CP) system are the most important in CHF. This generates a question as to whether the CB could serve as a target for some kind of treatment to reestablish control of cardiorespiratory balance in CHF. Any treatment would have to be based on a solid understanding of the mechanisms of chemosensing by the CB as well as the transducing of that sensing into neural activity sent to the medullary centers and regions of autonomic outflow to the periphery. Two avenues of treatment could be to (1) silence or attenuate the CB's neural output pharmacologically and (2) excise the CBS. There is a long history of CB removal mostly as a remedy for chronic obstructive lung disease. Results have been inconclusive as to the effectiveness of this procedure. But if carefully planned, the procedure might be a helpful treatment.

  14. Non-additive interactions between mitochondrial complex IV blockers and hypoxia in rat carotid body responses

    PubMed Central

    Donnelly, David F; Kim, Insook; Mulligan, Eileen M; Carroll, John L

    2013-01-01

    The metabolic hypothesis of carotid body chemoreceptor hypoxia transduction proposes an impairment of ATP production as the signal for activation. We hypothesized that mitochondrial complex IV blockers and hypoxia would act synergistically in exciting afferent nerve activity. Following a pretreatment with low dosage sodium cyanide (10-20μM), the hypoxia-induced nerve response was significantly reduced along with hypoxia-induced catecholamine release. However, in isolated glomus cells, the intracellular calcium response was enhanced as initially predicted. This suggests a cyanide-mediated impairment in the step between the glomus cell intracellular calcium rise and neurotransmitter release from secretory vesicles. Administration of a PKC blocker largely reversed the inhibitory actions of cyanide on the neural response. We conclude that the expected synergism between cyanide and hypoxia occurs at the level of glomus cell intracellular calcium but not at downstream steps due to a PKC-dependent inhibition of secretion. This suggests that at least one regulatory step beyond the glomus cell calcium response may modulate the magnitude of chemoreceptor responsiveness. PMID:24096081

  15. Effects of almitrine on the release of catecholamines from the rabbit carotid body in vitro.

    PubMed Central

    Almaraz, L.; Rigual, R.; Obeso, A.; Evrard, Y.; Gonzalez, C.

    1992-01-01

    1. Almitrine increases ventilation by stimulating the carotid body (CB) arterial chemoreceptors but neither its intraglomic target nor its mechanism of action have been elucidated. 2. We have tested the hypothesis that chemoreceptor cells are targets for almitrine by studying its effects on the release of 3H-catecholamines in an in vitro rabbit CB preparation. 3. It was found that almitrine (0.3 and 1.5 x 10(-6) M; i.e. 0.2 and 1 mg ml-1) increases the resting release of 3H-catecholamines from CBs (previously loaded with [3H]-tyrosine) incubated in a balanced 95% O2/5% CO2-equilibrated solution. 4. Almitrine at a concentration of 3 x 10(-6) M (2 mg l-1) also augmented the release of 3H-catecholamines elicited by incubating the CBs in a hypoxic solution (equilibrated with 7% O2/5% CO2 in N2), by high external K+ (35 mM) and by veratridine (2 x 10(-5) M), but did not modify release induced by dinitrophenol (7.5 x 10(-5) M). 5. At the same concentration (3 x 10(-6) M), almitrine increased the rate of dopamine synthesis and was ineffective in modifying the cyclic AMP levels in either normoxic or hypoxic CBs. 6. It is concluded that chemoreceptor cells are the intraglomic targets for almitrine. The mechanisms of action of almitrine on chemoreceptor cells are discussed. PMID:1504753

  16. Hypoxia transduction by carotid body chemoreceptors in mice lacking dopamine D(2) receptors.

    PubMed

    Prieto-Lloret, J; Donnelly, D F; Rico, A J; Moratalla, R; González, C; Rigual, R J

    2007-10-01

    Hypoxia-induced dopamine (DA) release from carotid body (CB) glomus cells and activation of postsynaptic D(2) receptors have been proposed to play an important role in the neurotransmission process between the glomus cells and afferent nerve endings. To better resolve the role of D(2) receptors, we examined afferent nerve activity, catecholamine content and release, and ventilation of genetically engineered mice lacking D(2) receptors (D(2)(-/-) mice). Single-unit afferent nerve activities of D(2)(-/-) mice in vitro were significantly reduced by 45% and 25% compared with wild-type (WT) mice during superfusion with saline equilibrated with mild hypoxia (Po(2) approximately 50 Torr) or severe hypoxia (Po(2) approximately 20 Torr), respectively. Catecholamine release in D(2)(-/-) mice was enhanced by 125% in mild hypoxia and 75% in severe hypoxia compared with WT mice, and the rate of rise was increased in D(2)(-/-) mice. We conclude that CB transduction of hypoxia is still present in D(2)(-/-) mice, but the response magnitude is reduced. However, the ventilatory response to acute hypoxia is maintained, perhaps because of an enhanced processing of chemoreceptor input by brain stem respiratory nuclei.

  17. Effects of mitochondrial poisons on glutathione redox potential and carotid body chemoreceptor activity.

    PubMed

    Gomez-Niño, A; Agapito, M T; Obeso, A; Gonzalez, C

    2009-01-01

    Low oxygen sensing in chemoreceptor cells involves the inhibition of specific plasma membrane K(+) channels, suggesting that mitochondria-derived reactive oxygen species (ROS) link hypoxia to K(+) channel inhibition, subsequent cell depolarization and activation of neurotransmitter release. We have used several mitochondrial poisons, alone and in combination with the antioxidant N-acetylcysteine (NAC), and quantify their capacity to alter GSH/GSSG levels and glutathione redox potential (E(GSH)) in rat diaphragm. Selected concentrations of mitochondrial poisons with or without NAC were tested for their capacity to activate neurotransmitter release in chemoreceptor cells and to alter ATP levels in intact rat carotid body (CB). We found that rotenone (1 microM), antimycin A (0.2 microg/ml) and sodium azide (5mM) decreased E(GSH); NAC restored E(GSH) to control values. At those concentrations mitochondrial poisons activated neurotransmitter release from CB chemoreceptor cells and decreased CB ATP levels, NAC being ineffective to modify these responses. Additional experiments with 3-nitroprionate (5mM), lower concentrations of rotenone and dinitrophenol revealed variable relationships between E(GSH) and chemoreceptor cell neurotransmitter release responses and ATP levels. These findings indicate a lack of correlation between mitochondrial-generated modifications of E(GSH) and chemoreceptor cells activity. This lack of correlation renders unlikely that alteration of mitochondrial production of ROS is the physiological pathway chemoreceptor cells use to signal hypoxia.

  18. Physiological Plasticity of Neural-Crest-Derived Stem Cells in the Adult Mammalian Carotid Body.

    PubMed

    Annese, Valentina; Navarro-Guerrero, Elena; Rodríguez-Prieto, Ismael; Pardal, Ricardo

    2017-04-18

    Adult stem cell plasticity, or the ability of somatic stem cells to cross boundaries and differentiate into unrelated cell types, has been a matter of debate in the last decade. Neural-crest-derived stem cells (NCSCs) display a remarkable plasticity during development. Whether adult populations of NCSCs retain this plasticity is largely unknown. Herein, we describe that neural-crest-derived adult carotid body stem cells (CBSCs) are able to undergo endothelial differentiation in addition to their reported role in neurogenesis, contributing to both neurogenic and angiogenic processes taking place in the organ during acclimatization to hypoxia. Moreover, CBSC conversion into vascular cell types is hypoxia inducible factor (HIF) dependent and sensitive to hypoxia-released vascular cytokines such as erythropoietin. Our data highlight a remarkable physiological plasticity in an adult population of tissue-specific stem cells and could have impact on the use of these cells for cell therapy. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  19. Plasticity in the brain: influence of bilateral carotid body resection (bCBR) on central CO2 sensitivity.

    PubMed

    Dahan, Albert; Sarton, Elise; Teppema, Luc

    2008-01-01

    We investigated the effect of bilateral carotid body resection (bCBR) in a patient with bilateral carotid body tumors on central CO2 sensitivity. We applied multiple square-wave changes in end-tidal CO2 and measured ventilation before the first surgery and at regular intervals for 3 years after surgery. The data were analyzed using a two-compartment model of the ventilatory control system. bCBR resulted in the loss of the fast response to CO2, and a sharp reduction in the magnitude of central CO2 sensitivity (a reduction of about 80% within 3 months after bCBR). Central CO2 sensitivity gradually increased to pre-operative values within 2 years after surgery. These observations are a strong indication for (1) the existence of a tonic influence from the peripheral chemoreceptors of the carotid bodies on central CO2 drive; (2) absence of any recovery of the peripheral drive after bCBR; and (3) neural plasticity causing the regeneration of central drive after bCBR.

  20. Carotid intima media thickness is associated with body fat abnormalities in HIV-infected patients

    PubMed Central

    2014-01-01

    Background HIV-infected patients may be at increased risk of cardiovascular (CV) events, and lipodystrophy is generally associated with proatherogenic metabolic disturbances. Carotid intima-media thickness (cIMT) has been used as a surrogate marker for atherosclerosis and it has been shown to be an independent risk factor for CV disease. Our objective was to evaluate cIMT in HIV-infected patients on combined anti-retroviral therapy (cART) with and without lipodystrophy defined by fat mass ratio (L-FMR), and to determine the association of lipodystrophy and visceral obesity [(visceral (VAT), subcutaneous adipose tissue (SAT) volume and VAT/SAT ratio, objectively evaluated by CT scan] with cIMT. Methods Cross-sectional study of 199 HIV-infected patients. Body composition by DXA and abdominal CT, lipids, blood pressure, inflammatory markers, and cIMT by ultrasonography were performed. L-FMR was defined as the ratio of the percentage of trunk fat mass to the percentage of lower limb fat mass by DXA. Categorical variables were compared using the chi-square or Fisher’s exact test. Spearman correlation coefficients were estimated to study the association between cIMT and clinical and metabolic characteristics. Means of cIMT, adjusted for age, were calculated, using generalized linear models. Results L-FMR was present in 41.2% of patients and cIMT was higher in these patients [0.81 (0.24) vs. 0.76 (0.25); p = 0.037)]. Lipodystrophic patients had higher VAT and VAT/SAT ratio and lower SAT. cIMT was associated with lipodystrophy evaluated by FMR, trunk fat, total abdominal fat, VAT and VAT/SAT ratio. No association was observed between cIMT and leg fat mass. Using generalized linear models, cIMT means were adjusted for age and no significant differences remained after this adjustment. The adjusted mean of cIMT was 0.787 (95% CI: 0.751-0.823) in patients without lipodystrophy, and 0.775 (95% CI: 0.732-0.817) in those with lipodystrophy (p = 0.671). Conclusions

  1. Color Doppler Ultrasound in Diagnosis and Assessment of Carotid Body Tumors: Comparison with Computed Tomography Angiography.

    PubMed

    Jin, Zhan-Qiang; He, Wen; Wu, Dong-Fang; Lin, Mei-Ying; Jiang, Hua-Tang

    2016-09-01

    A carotid body tumor (CBT) is a rare, non-chromaffin paraganglioma, and its diagnosis mainly depends on imaging modalities. The aim of this study was to investigate the ability of color Doppler ultrasound (CDU) in the diagnosis and assessment of CBT based on computed tomography (CT). We retrospectively reviewed the CDU and CT features of 49 consecutive CBTs and 23 schwannomas from 67 patients and compared these findings with surgical resection specimens. The mean size of CBT lesions on ultrasound scans and CT angiography (CTA) was 3.24 cm ± 0.82 cm (range, 1.6-5.2 cm) and 3.84 cm ± 1.08 cm (range, 1.8-6.8 cm), respectively, which had statistically significant difference (t = 9.815, p = 0.000). The vascularity of CBT lesions was richer than that of schwannoma lesions (p < 0.05). Intra-lesional vascularities feeding CBT mostly arose from the external carotid artery and had spectrum characteristics including low velocity and resistance. Peak systolic velocity (PSV) and resistance index (RI) of the vasa vasorum were 39.8 cm/s ± 19.8 cm/s and 0.54 ± 0.06, respectively. There was the correlation between CTA and CDU in identifying Shamblin type I CBT lesions, while CTA technique was superior for CDU, identifying Shamblin type II and III CBT lesions. Accuracy, specificity and sensitivity of CDU in diagnosing CBTs were 87.5% (63 of 72), 82.6% (19 of 23) and 89.8% (44 of 49), respectively. Both accuracy and sensitivity of CTA in diagnosing CBTs were 100%. CDU can be useful for assessment of Shamblin's type and intra-lesional blood flow of CBTs before its metastases, while CT imaging can reveal the relationship between lesions and adjacent arteries, as well as the involvement of the skull base. CDU combined with CT imaging can be used as an optimal detection modality for the assessment and management of CBT.

  2. Body size and metabolic differences in Maine Coon cats with and without hypertrophic cardiomyopathy.

    PubMed

    Freeman, Lisa M; Rush, John E; Meurs, Kathryn M; Bulmer, Barret J; Cunningham, Suzanne M

    2013-02-01

    An interplay between growth, glucose regulation and hypertrophic cardiomyopathy (HCM) may exist, but has not been studied in detail. The purpose of this study was to characterize morphometric features, insulin-like growth factor-1 (IGF-1) and glucose metabolism in Maine Coon cats with HCM. Body weight, body condition score (BCS), head length and width, and abdominal circumference were measured in Maine Coon cats >2 years of age. Echocardiography and thoracic radiography (for measurement of humerus length, and fourth and twelfth vertebrae length) were also performed. Blood was collected for biochemistry profile, DNA testing, insulin and IGF-1. Sixteen of 63 cats had HCM [myosin binding protein C (MYBPC)+, n = 3 and MYBPC-, n = 13] and 47/63 were echocardiographically normal (MYBPC+, n = 17 and MYBPC-, n = 30). There were no significant differences in any measured parameter between MYBPC+ and MYBPC- cats. Cats with HCM were significantly older (P <0.001), heavier (P = 0.006), more obese (P = 0.008), and had longer humeri (P = 0.02) compared with the HCM- group. Cats with HCM also had higher serum glucose (P = 0.01), homeostasis model assessment (HOMA) and IGF-1 (P = 0.01) concentrations, were from smaller litters (P = 0.04), and were larger at 6 months (P = 0.02) and at 1 year of age (P = 0.03). Multivariate analysis revealed that age (P <0.001), BCS (P = 0.03) and HOMA (P = 0.047) remained significantly associated with HCM. These results support the hypothesis that early growth and nutrition, larger body size and obesity may be environmental modifiers of genetic predisposition to HCM. Further studies are warranted to evaluate the effects of early nutrition on the phenotypic expression of HCM.

  3. Adrenaline release evokes hyperpnoea and an increase in ventilatory CO2 sensitivity during hypoglycaemia: a role for the carotid body.

    PubMed

    Thompson, Emma L; Ray, Clare J; Holmes, Andrew P; Pye, Richard L; Wyatt, Christopher N; Coney, Andrew M; Kumar, Prem

    2016-08-01

    Hypoglycaemia is counteracted by release of hormones and an increase in ventilation and CO2 sensitivity to restore blood glucose levels and prevent a fall in blood pH. The full counter-regulatory response and an appropriate increase in ventilation is dependent on carotid body stimulation. We show that the hypoglycaemia-induced increase in ventilation and CO2 sensitivity is abolished by preventing adrenaline release or blocking its receptors. Physiological levels of adrenaline mimicked the effect of hypoglycaemia on ventilation and CO2 sensitivity. These results suggest that adrenaline, rather than low glucose, is an adequate stimulus for the carotid body-mediated changes in ventilation and CO2 sensitivity during hypoglycaemia to prevent a serious acidosis in poorly controlled diabetes. Hypoglycaemia in vivo induces a counter-regulatory response that involves the release of hormones to restore blood glucose levels. Concomitantly, hypoglycaemia evokes a carotid body-mediated hyperpnoea that maintains arterial CO2 levels and prevents respiratory acidosis in the face of increased metabolism. It is unclear whether the carotid body is directly stimulated by low glucose or by a counter-regulatory hormone such as adrenaline. Minute ventilation was recorded during infusion of insulin-induced hypoglycaemia (8-17 mIU kg(-1)  min(-1) ) in Alfaxan-anaesthetised male Wistar rats. Hypoglycaemia significantly augmented minute ventilation (123 ± 4 to 143 ± 7 ml min(-1) ) and CO2 sensitivity (3.3 ± 0.3 to 4.4 ± 0.4 ml min(-1)  mmHg(-1) ). These effects were abolished by either β-adrenoreceptor blockade with propranolol or adrenalectomy. In this hypermetabolic, hypoglycaemic state, propranolol stimulated a rise in P aC O2, suggestive of a ventilation-metabolism mismatch. Infusion of adrenaline (1 μg kg(-1)  min(-1) ) increased minute ventilation (145 ± 4 to 173 ± 5 ml min(-1) ) without altering P aC O2 or pH and enhanced ventilatory CO2 sensitivity (3

  4. Expression of nitric oxide-containing structures in the rat carotid body.

    PubMed

    Atanasova, Dimitrinka Y; Dimitrov, Nikolay D; Lazarov, Nikolai E

    2016-10-01

    The carotid body (CB) is a major peripheral arterial chemoreceptor organ that evokes compensatory reflex responses so as to maintain gas homeostasis. It is dually innervated by sensory fibers from petrosal ganglion (PG) neurons, and autonomic fibers from postganglionic sympathetic neurons of the superior cervical ganglion (SCG) and parasympathetic vasomotor fibers of intrinsic ganglion cells in the CB. The presence of nitric oxide (NO), a putative gaseous neurotransmitter substance in a number of neuronal and non-neuronal structures, was examined in the CB, PG and SCG of the rat using nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) histochemistry, nitric oxide synthase (NOS) immunohistochemistry and retrograde tracing. One week after injecting the retrograde tracer Fast Blue (FB) in the CB, we found that a subset of perikarya in the caudal portions of the PG and SCG were FB-labeled. Histochemistry and immunohistochemistry revealed that the majority of large- and medium-sized PG and SCG cells were NADPH-d positive and displayed a strong NOS immunostaining. We also observed that many varicose nerve fibers penetrating the CB and enveloping the glomus cells and blood vessels were NADPH-d reactive and expressed the constitutive isoforms of NOS, nNOS and eNOS. In addition, some autonomic microganglion cells embedded within, or located at the periphery of the CB, and not glomus or sustentacular cells were nNOS-immunopositive while CB microvasculature expressed eNOS. The present results suggest that NO is a transmitter in the autonomic nerve endings supplying the CB and is involved in efferent chemoreceptor inhibition by a dual mechanism.

  5. Ionic mechanisms for the transduction of acidic stimuli in rabbit carotid body glomus cells.

    PubMed Central

    Rocher, A; Obeso, A; Gonzalez, C; Herreros, B

    1991-01-01

    1. The release of [3H]dopamine (DA) in response to inhibition of the Na+ pump or to intracellular acid load was studied in rabbit carotid bodies (CB) previously incubated with the precursor [3H]tyrosine. The ionic requirements of the release response and the involvement of specific ion transport systems were investigated. 2. Inhibition of the Na+ pump, by incubating the CB with ouabain or in K(+)-free medium, evokes a DA release response which requires the presence of Na+ and Ca2+ in the medium and is insensitive to nisoldipine. This suggests that the response is triggered by entry of external Ca2+ through Na(+)-Ca2+ exchange, a consequence of the increase in intracellular Na+ resulting from inhibition of the pump. 3. Incubation of the CB in medium equilibrated with 20% CO2 at pH 6.6, or in medium containing the protonophore dinitrophenol (DNP) or the weak acid propionate, elicits a DA release response which requires also the presence of Na+ and Ca2+ in the medium and is insensitive to dihydropyridines. 4. Ethylisopropylamiloride (EIPA), an inhibitor of the Na(+)-H+ exchanger, markedly decreases the release response elicited by DNP or propionate in bicarbonate-free medium, but has not any effect in bicarbonate-buffered medium. In the latter condition, the EIPA-insensitive release of DA is inhibited by reducing the HCO3- concentration in the medium to 2 mM or by removal of Cl-, suggesting that in bicarbonate-buffered medium a Na(+)-dependent HCO3(-)-Cl- exchanger is involved in the release response. 5. It is concluded that the release of DA by the chemoreceptor cells in response to acidic stimulation is triggered by entry of external Ca2+ through Na(+)-Ca2+ exchange. This exchange is promoted by the increase of intracellular Na+ that results from the operation of Na(+)-coupled H(+)-extruding mechanisms activated by the acid load. PMID:1668755

  6. Some reflections on intermittent hypoxia. Does it constitute the translational niche for carotid body chemoreceptor researchers?

    PubMed

    Gonzalez, Constancio; Yubero, Sara; Gomez-Niño, M Angela; Agapito, Teresa; Rocher, Asuncion; Rigual, Ricardo; Obeso, Ana; Montserrat, Jose M

    2012-01-01

    The views presented in this article are the fruit of reflections and discussion with my colleagues at Valladolid and with the members of the Sleep Apnea Hypopnea Syndrome Group of the CIBERES (Spain). We have assembled the article in three sections. In the first one we provide a mechanistic description of obstructive sleep apnea (OSA) and all of its components, including the repetitive episodes of upper airways (UA) obstruction and accompanying hypoxic hypoxia, the respiratory efforts to fight and overcome the obstruction, and the sleep fragmentation due to the hypoxia-triggered arousal reactions, all events occurring during sleep hours with frequencies that might reach up >40-50 episodes/sleep hour. When OSA is accompanied by some of the elements of a big cohort of associated pathologies (vascular, metabolic, and neuropsychiatric) it conforms the obstructive sleep apnea syndrome (OSAS). The high frequency of OSAS in adults (>35 years old) and the costs in every regard of the treatment makes the syndrome a primary importance socio-sanitary problem. In the second section, we describe the experimental models of OSAS, basically the episodic repetitive hypoxic model described by Fletcher and coworkers in 1992, today named in short intermittent hypoxia (IH). From these lines, we want to call for some kind of consensus among researchers to lessen the dispersion of IH protocols. Finally, in the last section we intend to share our optimism with all ISAC members. The optimism is based on the recognition that carotid body (CB) chemoreceptors are critical elements of one of the main pathophysiologic loops in the genesis of OSAS. Therefore, we believe that all of us, as ISAC members, are well qualified to contribute in multidisciplinary research teams with well defined translational interests.

  7. Paracrine Signaling in Glial-Like Type II Cells of the Rat Carotid Body.

    PubMed

    Murali, Sindhubarathi; Zhang, Min; Nurse, Colin A

    2015-01-01

    The carotid body (CB) chemosensory complex uses ATP as a key excitatory neurotransmitter that is the main contributor to the sensory discharge during acute hypoxia. The complex includes receptor type I cells, which depolarize and release various neurochemicals including ATP during hypoxia, and contiguous glial-like type II cells which express purinergic P2Y2 receptors (P2Y2R). We previously showed that activation of P2Y2R on rat type II cells led to the opening of pannexin-1 (Panx-1) channels, which acted as conduits for the further release of ATP. More recently, we considered the possibility that other CB neuromodulators may have a similar paracrine role, leading to the activation of type II cells. Here, we examine the evidence that angiotensin II (ANG II), endothelin- (ET-1), and muscarinic agonists (e.g. acetylcholine, ACh) may activate intracellular Ca(2+) signals in type II cells and, in the case of ANG II and ACh, Panx-1 currents as well. Using ratiometric Ca(2+) imaging, we found that a substantial population of type II cells responded to 100 nM ANG II with a robust rise in intracellular Ca(2+) and activation of Panx-1 current. Both effects of ANG II were mediated via AT(1) receptors (AT(1)Rs) and current activation could be inhibited by the Panx-1 channel blocker, carbenoxolone (CBX; 5 μM). Additionally, low concentrations of ET-1 (1 nM) evoked robust intracellular Ca(2+) responses in subpopulations of type II cells. The mAChR agonist muscarine (10 μM) also induced a rise in intracellular Ca(2+) in some type II cells, and preliminary perforated-patch, whole-cell recordings revealed that ACh (10 μM) may activate Panx-1-like currents. These data suggest that paracrine activation of type II cells by endogenous neuromodulators may be a common feature of signal processing in the rat CB.

  8. Characterization of ectonucleotidase expression in the rat carotid body: regulation by chronic hypoxia.

    PubMed

    Salman, Shaima; Vollmer, Cathy; McClelland, Grant B; Nurse, Colin A

    2017-09-01

    The carotid body (CB) chemoreflex maintains blood Po2 and Pco2/H(+) homeostasis and displays sensory plasticity during exposure to chronic hypoxia. Purinergic signaling via P1 and P2 receptors plays a pivotal role in shaping the afferent discharge at the sensory synapse containing catecholaminergic chemoreceptor (type I) cells, glial-like type II cells, and sensory (petrosal) nerve endings. However, little is known about the family of ectonucleotidases that control synaptic nucleotide levels. Using quantitative PCR (qPCR), we first compared expression levels of ectonucleoside triphosphate diphosphohydrolases (NTPDases1,2,3,5,6) and ecto-5'-nucleotidase (E5'Nt/CD73) mRNAs in juvenile rat CB vs. brain, petrosal ganglia, sympathetic (superior cervical) ganglia, and a sympathoadrenal chromaffin (MAH) cell line. In whole CB extracts, qPCR revealed a high relative expression of surface-located members NTPDase1,2 and E5'Nt/CD73, compared with low NTPDase3 expression. Immunofluorescence staining of CB sections or dissociated CB cultures localized NTPDase2,3 and E5'Nt/CD73 protein to the periphery of type I clusters, and in association with sensory nerve fibers and/or isolated type II cells. Interestingly, in CBs obtained from rats reared under chronic hypobaric hypoxia (~60 kPa, equivalent to 4,300 m) for 5-7 days, in addition to the expected upregulation of tyrosine hydroxylase and VEGF mRNAs, there was a significant upregulation of NTPDase3 and E5'Nt/CD73 mRNA, but a downregulation of NTPDase1 and NTPDase2 relative to normoxic controls. We conclude that NTPDase1,2,3 and E5'Nt/CD73 are the predominant surface-located ectonucleotidases in the rat CB and suggest that their differential regulation during chronic hypoxia may contribute to CB plasticity via control of synaptic ATP, ADP, and adenosine pools. Copyright © 2017 the American Physiological Society.

  9. Glucose sensing by carotid body glomus cells: potential implications in disease

    PubMed Central

    Gao, Lin; Ortega-Sáenz, Patricia; García-Fernández, María; González-Rodríguez, Patricia; Caballero-Eraso, Candela; López-Barneo, José

    2014-01-01

    The carotid body (CB) is a key chemoreceptor organ in which glomus cells sense changes in blood O2, CO2, and pH levels. CB glomus cells have also been found to detect hypoglycemia in both non-primate mammals and humans. O2 and low-glucose responses share a common final pathway involving membrane depolarization, extracellular calcium influx, increase in cytosolic calcium concentration, and neurotransmitter secretion, which stimulates afferent sensory fibers to evoke sympathoadrenal activation. On the other hand, hypoxia and low glucose induce separate signal transduction pathways. Unlike O2 sensing, the response of the CB to low glucose is not altered by rotenone, with the low glucose-activated background cationic current unaffected by hypoxia. Responses of the CB to hypoglycemia and hypoxia can be potentiated by each other. The counter-regulatory response to hypoglycemia by the CB is essential for the brain, an organ that is particularly sensitive to low glucose. CB glucose sensing could be altered in diabetic patients, particularly those under insulin treatment, as well as in other medical conditions such as sleep apnea or obstructive pulmonary diseases, where chronic hypoxemia presents with plastic modifications in CB structure and function. The current review will focus on the following main aspects: (1) the CB as a low glucose sensor in both in vitro and in vivo models; (2) molecular and ionic mechanisms of low glucose sensing by glomus cells, (3) the interplay between low glucose and O2 sensing in CB, and (4) the role of CB low glucose sensing in the pathophysiology of cardiorespiratory and metabolic diseases, and how this may serve as a potential therapeutic target. PMID:25360117

  10. Purinergic stimulation of carotid body efferent glossopharyngeal neurones increases intracellular Ca2+ and nitric oxide production.

    PubMed

    Lowe, Michael; Park, Sung Jin; Nurse, Colin A; Campanucci, Verónica A

    2013-07-01

    The mammalian carotid body (CB) is a peripheral chemosensory organ that controls ventilation and is innervated by both afferent and efferent nerve fibres. The afferent pathway is stimulated by chemoexcitants, such as hypoxia, hypercapnia and acidosis. The efferent pathway causes inhibition of the sensory discharge via release of NO that originates mainly from neuronal nitric oxide synthase (nNOS)-positive autonomic neurones within the glossopharyngeal nerve (GPN). Recent studies in the rat indicate that these inhibitory GPN neurones and their processes express purinergic P2X receptors and can be activated by ATP, a key excitatory CB neurotransmitter. Here we tested the hypothesis that purinergic agonists stimulate a rise in [Ca(2+)]i, leading to nNOS activation and NO production in isolated GPN neurones, using the fluorescent probes fura-2 and 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM DA), respectively. ATP caused a dose-dependent increase in [Ca(2+)]i in GPN neurones (EC50 ≈ 1.92 μm) that was markedly inhibited by a combination of 100 μm suramin (a non-specific P2X blocker) and 100 nm Brilliant Blue G (a selective P2X7 blocker). ATP also stimulated NO production in GPN neurones, as revealed by an increase in DAF fluorescence; this NO signal was inhibited by purinergic blockers, chelators of extracellular Ca(2+), the nNOS inhibitor l-NAME and the NO scavenger carboxy-PTIO. The P2X2/3 and P2X7 agonists α,β,-methylene ATP and benzoyl ATP mimicked the effects of ATP. Taken together, these data indicate that ATP may contribute to negative feedback inhibition of CB sensory discharge via purinergic stimulation of NO production in efferent fibres.

  11. Carotid Body Ablation Abrogates Hypertension and Autonomic Alterations Induced by Intermittent Hypoxia in Rats.

    PubMed

    Del Rio, Rodrigo; Andrade, David C; Lucero, Claudia; Arias, Paulina; Iturriaga, Rodrigo

    2016-08-01

    Chronic intermittent hypoxia (CIH), the main feature of obstructive sleep apnea, enhances carotid body (CB) chemosensory responses to hypoxia and produces autonomic dysfunction, cardiac arrhythmias, and hypertension. We tested whether autonomic alterations, arrhythmogenesis, and the progression of hypertension induced by CIH depend on the enhanced CB chemosensory drive, by ablation of the CB chemoreceptors. Male Sprague-Dawley rats were exposed to control (Sham) conditions for 7 days and then to CIH (5% O2, 12/h 8 h/d) for a total of 28 days. At 21 days of CIH exposure, rats underwent bilateral CB ablation and then exposed to CIH for 7 additional days. Arterial blood pressure and ventilatory chemoreflex response to hypoxia were measured in conscious rats. In addition, cardiac autonomic imbalance, cardiac baroreflex gain, and arrhythmia score were assessed during the length of the experiments. In separate experimental series, we measured extracellular matrix remodeling content in cardiac atrial tissue and systemic oxidative stress. CIH induced hypertension, enhanced ventilatory response to hypoxia, induced autonomic imbalance toward sympathetic preponderance, reduced baroreflex gain, and increased arrhythmias and atrial fibrosis. CB ablation normalized blood pressure, reduced ventilatory response to hypoxia, and restored cardiac autonomic and baroreflex function. In addition, CB ablation reduced the number of arrhythmias, but not extracellular matrix remodeling or systemic oxidative stress, suggesting that reductions in arrhythmia incidence during CIH were related to normalization of cardiac autonomic balance. Present results show that autonomic alterations induced by CIH are critically dependent on the CB and support a main role for the CB in the CIH-induced hypertension. © 2016 American Heart Association, Inc.

  12. Intermittent Hypoxia-Induced Carotid Body Chemosensory Potentiation and Hypertension Are Critically Dependent on Peroxynitrite Formation

    PubMed Central

    Moya, Esteban A.; Arias, Paulina; Varela, Carlos; Oyarce, María P.; Del Rio, Rodrigo; Iturriaga, Rodrigo

    2016-01-01

    Oxidative stress is involved in the development of carotid body (CB) chemosensory potentiation and systemic hypertension induced by chronic intermittent hypoxia (CIH), the main feature of obstructive sleep apnea. We tested whether peroxynitrite (ONOO−), a highly reactive nitrogen species, is involved in the enhanced CB oxygen chemosensitivity and the hypertension during CIH. Accordingly, we studied effects of Ebselen, an ONOO− scavenger, on 3-nitrotyrosine immunoreactivity (3-NT-ir) in the CB, the CB chemosensory discharge, and arterial blood pressure (BP) in rats exposed to CIH. Male Sprague-Dawley rats were exposed to CIH (5% O2, 12 times/h, 8 h/day) for 7 days. Ebselen (10 mg/kg/day) was administrated using osmotic minipumps and BP measured with radiotelemetry. Compared to the sham animals, CIH-treated rats showed increased 3-NT-ir within the CB, enhanced CB chemosensory responses to hypoxia, increased BP response to acute hypoxia, and hypertension. Rats treated with Ebselen and exposed to CIH displayed a significant reduction in 3-NT-ir levels (60.8 ± 14.9 versus 22.9 ± 4.2 a.u.), reduced CB chemosensory response to 5% O2 (266.5 ± 13.4 versus 168.6 ± 16.8 Hz), and decreased mean BP (116.9 ± 13.2 versus 82.1 ± 5.1 mmHg). Our results suggest that CIH-induced CB chemosensory potentiation and hypertension are critically dependent on ONOO− formation. PMID:26798430

  13. Glycogen metabolism protects against metabolic insult to preserve carotid body function during glucose deprivation

    PubMed Central

    Holmes, Andrew P; Turner, Philip J; Carter, Paul; Leadbeater, Wendy; Ray, Clare J; Hauton, David; Buckler, Keith J; Kumar, Prem

    2014-01-01

    The view that the carotid body (CB) type I cells are direct physiological sensors of hypoglycaemia is challenged by the finding that the basal sensory neuronal outflow from the whole organ is unchanged in response to low glucose. The reason for this difference in viewpoint and how the whole CB maintains its metabolic integrity when exposed to low glucose is unknown. Here we show that, in the intact superfused rat CB, basal sensory neuronal activity was sustained during glucose deprivation for 29.1 ± 1.2 min, before irreversible failure following a brief period of excitation. Graded increases in the basal discharge induced by reducing the superfusate led to proportional decreases in the time to the pre-failure excitation during glucose deprivation which was dependent on a complete run-down in glycolysis and a fall in cellular energy status. A similar ability to withstand prolonged glucose deprivation was observed in isolated type I cells. Electron micrographs and immunofluorescence staining of rat CB sections revealed the presence of glycogen granules and the glycogen conversion enzymes glycogen synthase I and glycogen phosphorylase BB, dispersed throughout the type I cell cytoplasm. Furthermore, pharmacological attenuation of glycogenolysis and functional depletion of glycogen both significantly reduced the time to glycolytic run-down by ∼33 and 65%, respectively. These findings suggest that type I cell glycogen metabolism allows for the continuation of glycolysis and the maintenance of CB sensory neuronal output in periods of restricted glucose delivery and this may act as a key protective mechanism for the organ during hypoglycaemia. The ability, or otherwise, to preserve energetic status may thus account for variation in the reported capacity of the CB to sense physiological glucose concentrations and may even underlie its function during pathological states associated with augmented CB discharge. PMID:25063821

  14. Glycogen metabolism protects against metabolic insult to preserve carotid body function during glucose deprivation.

    PubMed

    Holmes, Andrew P; Turner, Philip J; Carter, Paul; Leadbeater, Wendy; Ray, Clare J; Hauton, David; Buckler, Keith J; Kumar, Prem

    2014-10-15

    The view that the carotid body (CB) type I cells are direct physiological sensors of hypoglycaemia is challenged by the finding that the basal sensory neuronal outflow from the whole organ is unchanged in response to low glucose. The reason for this difference in viewpoint and how the whole CB maintains its metabolic integrity when exposed to low glucose is unknown. Here we show that, in the intact superfused rat CB, basal sensory neuronal activity was sustained during glucose deprivation for 29.1 ± 1.2 min, before irreversible failure following a brief period of excitation. Graded increases in the basal discharge induced by reducing the superfusate PO2 led to proportional decreases in the time to the pre-failure excitation during glucose deprivation which was dependent on a complete run-down in glycolysis and a fall in cellular energy status. A similar ability to withstand prolonged glucose deprivation was observed in isolated type I cells. Electron micrographs and immunofluorescence staining of rat CB sections revealed the presence of glycogen granules and the glycogen conversion enzymes glycogen synthase I and glycogen phosphorylase BB, dispersed throughout the type I cell cytoplasm. Furthermore, pharmacological attenuation of glycogenolysis and functional depletion of glycogen both significantly reduced the time to glycolytic run-down by ∼33 and 65%, respectively. These findings suggest that type I cell glycogen metabolism allows for the continuation of glycolysis and the maintenance of CB sensory neuronal output in periods of restricted glucose delivery and this may act as a key protective mechanism for the organ during hypoglycaemia. The ability, or otherwise, to preserve energetic status may thus account for variation in the reported capacity of the CB to sense physiological glucose concentrations and may even underlie its function during pathological states associated with augmented CB discharge.

  15. Uric acid, carotid intima-media thickness and body composition in prepubertal children.

    PubMed

    Bassols, J; Martínez-Calcerrada, J M; Prats-Puig, A; Carreras-Badosa, G; Díaz-Roldán, F; Osiniri, I; Riera-Pérez, E; de Zegher, F; Ibáñez, L; López-Bermejo, A

    2016-10-01

    Increased uric acid is an independent biomarker for cardiovascular disease in obese adolescents and adults. We investigated whether uric acid relates to carotid intima-media thickness (cIMT) in prepubertal children, and whether body mass index (BMI) and preperitoneal fat modulate this association. 359 asymptomatic prepubertal Caucasian children were stratified according to BMI categories (171 with BMI-SDS < 0; 188 with BMI-SDS ≥ 0) and according to preperitoneal fat levels (180 with preperitoneal fat <50th centile; 179 with preperitoneal fat >50th centile). Uric acid levels, insulin resistance (homeostasis model assessment insulin resistance; HOMA-IR), C-reactive protein (CRP), triacylglycerol (TG), systolic blood pressure (SBP), abdominal fat and cIMT (both by ultrasound) were assessed. Uric acid was associated with several cardiovascular risk factors, namely higher HOMA-IR, CRP, TG, BMI, waist, SBP, preperitoneal fat and cIMT (all P < 0.001 to P < 0.0001). Significant BMI and preperitoneal fat interactions were documented in the relationship between uric acid and cIMT (both P < 0.05), as uric acid was preferentially related to cIMT in heavier children (β = 0.247, P < 0.001, r(2)  = 9.1%) and in children with more preperitoneal fat (β = 0.263, P < 0.0001, r(2)  = 11.9%). Serum uric acid is associated with cIMT in asymptomatic prepubertal children. Both higher BMI and preperitoneal fat aggravate the potential risk of atherosclerotic disease imposed by higher concentrations of uric acid. © 2015 World Obesity.

  16. Glucose sensing by carotid body glomus cells: potential implications in disease.

    PubMed

    Gao, Lin; Ortega-Sáenz, Patricia; García-Fernández, María; González-Rodríguez, Patricia; Caballero-Eraso, Candela; López-Barneo, José

    2014-01-01

    The carotid body (CB) is a key chemoreceptor organ in which glomus cells sense changes in blood O2, CO2, and pH levels. CB glomus cells have also been found to detect hypoglycemia in both non-primate mammals and humans. O2 and low-glucose responses share a common final pathway involving membrane depolarization, extracellular calcium influx, increase in cytosolic calcium concentration, and neurotransmitter secretion, which stimulates afferent sensory fibers to evoke sympathoadrenal activation. On the other hand, hypoxia and low glucose induce separate signal transduction pathways. Unlike O2 sensing, the response of the CB to low glucose is not altered by rotenone, with the low glucose-activated background cationic current unaffected by hypoxia. Responses of the CB to hypoglycemia and hypoxia can be potentiated by each other. The counter-regulatory response to hypoglycemia by the CB is essential for the brain, an organ that is particularly sensitive to low glucose. CB glucose sensing could be altered in diabetic patients, particularly those under insulin treatment, as well as in other medical conditions such as sleep apnea or obstructive pulmonary diseases, where chronic hypoxemia presents with plastic modifications in CB structure and function. The current review will focus on the following main aspects: (1) the CB as a low glucose sensor in both in vitro and in vivo models; (2) molecular and ionic mechanisms of low glucose sensing by glomus cells, (3) the interplay between low glucose and O2 sensing in CB, and (4) the role of CB low glucose sensing in the pathophysiology of cardiorespiratory and metabolic diseases, and how this may serve as a potential therapeutic target.

  17. Study of the effects of age and body mass index on the carotid wall vibration: extraction methodology and analysis.

    PubMed

    Yousefi Rizi, Fereshteh; Setarehdan, Seyed Kamaledin; Behnam, Hamid; Alizadeh Sani, Zahra

    2014-07-01

    This study aims to non-invasively extract the vibrations of the carotid wall and evaluate the changes in the carotid artery wall caused by age and obesity. Such evaluation can increase the possibility of detecting wall stiffness and atherosclerosis in its early stage. In this study, a novel method that uses a phase-tracking method based on the continuous wavelet transform calculates the carotid wall motion from the ultrasound radio frequency signals. To extract the high-frequency components of the wall motion, wall vibration, the empirical mode decomposition was then used. The posterior wall (intima-media) motion and vibration were extracted for 54 healthy volunteers (mean age: 33.87 ± 14.73 years), including 13 overweight subjects (body mass index > 25) and 14 female participants using their radio frequency signals. The results showed that the dominant frequency of the wall vibration correlates with age (r = -0.5887, p < 0.001) and body mass index (r = -0.4838, p < 0.001). The quantitative analysis further demonstrated that the dominant frequency of the vibration in the radial direction of the carotid wall decreases by age and is lower in overweight subjects. Besides, the peak-to-peak amplitude of the wall vibration showed significant correlations with age (r = -0.5456, p < 0.001) and body mass index (r = -0.5821, p < 0.001). The peak-to-peak amplitude also decreases by age and is lower in overweight subjects. However, there were no significant correlations between these features of the wall vibrations and systolic/diastolic blood pressure and sex. Our proposed measures were certified using the calculated arterial stiffness indices. The average power spectrum of the elderly subjects'wall motion in the frequency range of the wall vibration (>100 Hz) is decreased more in comparison with the young subjects. Our results revealed that the proposed method may be useful for detecting the stiffness and distortion in the carotid wall that occur prior to wall thickening

  18. [Effect of mammillary body ablation on extinctive inhibition in cats].

    PubMed

    Voronin, L G; Nikol'skaia, K A

    1978-01-01

    Chronic extinction of chain closed conditioned reflex in intact rabbits took five to six days. The order of extinction of the reflex links was as follows: the nearer to reinforcement the link of the chain, the sooner it was inhibited. In the course of extinction different "compensatory" movements appeared with a high frequency. Unlike the conditioned movements they were not fully extinguished: in the rest periods (lying for 4 to 10 min.), running and sniffing took place 4 to 8 times in the session. After the ablation of the mammilary bodies, extinctive inhibition was developing slower (9 to 13 days) than in the norm. The order of extinction became reverse: the nearer the link of the chain to reinforcement, the greater the difficulty of inhibition. The appearance of "compensatory" movements sharply differed from the norm. The general behaviour of the operated rabbits was peculiar in that during extinction of conditioned movements the short periods of rest (1 to 3 min.) alternated with running, sitting, scratching, washing, etc.

  19. Whole body computed tomographic characteristics of skeletal and cardiac muscular metastatic neoplasia in dogs and cats.

    PubMed

    Vignoli, Massimo; Terragni, Rossella; Rossi, Federica; Frühauf, Lukas; Bacci, Barbara; Ressel, Lorenzo; Capitani, Ombretta; Marconato, Laura

    2013-01-01

    Muscular metastatic neoplasia has been reported to be rare in domestic animals, however previous studies were based primarily on necropsy findings. The purpose of this retrospective study was to describe whole body computed tomography (CT) characteristics of confirmed muscular metastases in a cohort of dogs and cats presented for oncology evaluation. Medical records of 1201 oncology patients were reviewed. Included animals underwent pre and postcontrast whole body CT, and CT-guided tru-cut biopsy or fine needle aspiration of one or more metastatic lesions. Twenty-one dogs and six cats met inclusion criteria, representing 2.08% of all canine oncology patients and 3.1% of all feline oncology patients. Mean age was 9.6 years. Postcontrast CT characteristics included well-demarcated, oval-to-round lesions with varying enhancement patterns: ring enhancing (n = 16), heterogeneously enhancing (n = 8), or homogeneously enhancing (n = 5). Five animals showed concurrent and varying nodular patterns. In seven cases (five dogs and two cats), one single muscular nodule was observed. In 20 cases, two or more lesions were observed. In two cases, cardiac hypodense nodules were observed in the postcontrast CT, while appearing isodense in the precontrast study. Necropsy confirmed neoplasia in both of them. Locations of muscular metastases included epaxial/paraspinal muscles of the cervical, thoracic, and lumbar spine (n = 18), superficial muscles of the thoracic wall (n = 13), scapular/shoulder region (n = 3), hind limb (n = 3), and abdominal wall muscles (n = 1). Findings supported the use of pre and postcontrast whole body CT for oncologic staging in dogs and cats, especially for primary tumors characterized by a high metastatic rate.

  20. Reduced to oxidized glutathione ratios and oxygen sensing in calf and rabbit carotid body chemoreceptor cells

    PubMed Central

    Sanz-Alfayate, G; Obeso, A; Agapito, M T; González, C

    2001-01-01

    The aim of this work was to test the redox hypotheses of O2 chemoreception in the carotid body (CB). They postulate that hypoxia alters the levels of reactive oxygen species (ROS) and the ratio of reduced to oxidized glutathione (GSH/GSSG), causing modifications to the sulfhydryl groups/disulfide bonds of K+ channel proteins, which leads to the activation of chemoreceptor cells. We found that the GSH/GSSG ratio in normoxic calf CB (30.14 ± 4.67; n = 12) and hypoxic organs (33.03 ± 6.88; n = 10), and the absolute levels of total glutathione (0.71 ± 0.07 nmol (mg tissue)−1, normoxia vs. 0.76 ± 0.07 nmol (mg tissue)−1, hypoxia) were not statistically different. N-Acetylcysteine (2 mm; NAC), a precursor of glutathione and ROS scavenger, increased normoxic glutathione levels to 1.03 ± 0.06 nmol (mg tissue)−1 (P < 0.02) and GSH/GSSG ratios to 59.05 ± 5.05 (P < 0.001). NAC (20 μm–10 mm) did not activate or inhibit chemoreceptor cells as it did not alter the normoxic or the hypoxic release of 3H-catecholamines (3H-CAs) from rabbit and calf CBs whose CA deposits had been labelled by prior incubation with the natural CA precursor 3H-tyrosine. NAC (2 mm) was equally ineffective in altering the release of 3H-CAs induced by stimuli (high external K+ and ionomycin) that bypass the initial steps of the hypoxic cascade of activation of chemoreceptor cells, thereby excluding the possibility that the lack of effect of NAC on normoxic and hypoxic release of 3H-CAs results from a concomitant alteration of Ca2+ channels or of the exocytotic machinery. The present findings do not support the contention that O2 chemoreception in the CB is linked to variations in the GSH/GSSG quotient as the redox models propose. PMID:11711574

  1. Comparison of retrocarotid and caudocranial dissection techniques for the surgical treatment of carotid body tumors.

    PubMed

    Hinojosa, Carlos A; Ortiz-Lopez, Laura J; Anaya-Ayala, Javier E; Orozco-Sevilla, Vicente; Nunez-Salgado, Ana E

    2015-10-01

    Carotid body tumors (CBTs) are rare neoplasms. Complete surgical resection is the curative therapy and is considered the therapeutic gold standard. This study compared the retrocarotid dissection (RCD) technique with the standard caudocranial dissection (SCCD) technique in operative time, blood loss, vascular or nerve injuries, and hospital stay. A retrospective review was conducted of patients with CBTs who underwent surgical treatment with the RCD technique at the National Institute of Medical Sciences and Nutrition "Salvador Zubirán" in Mexico City from July 2007 to January 2013. This cohort was compared with an historical cohort treated with standard SCCD from 1995 to 2007 at the same institution. A total of 68 procedures (41 SCCD, 27 RCD) were performed in 68 patients (91% women) with a mean age of 54 years (standard deviation [SD], 15 years). According to the Shamblin classification, 6 CBTs were type I (9%), 35 were type II (51%), and 27 were type III (40%). Comparative analysis identified mean blood loss of 480 mL (SD, 380 mL) in the RCD group and 690 mL (SD, 680 mL) for the SCCD cohort (P < .31). The mean procedural time was 172 minutes (SD, 60 minutes) for the RCD group and 260 minutes (SD, 100 minutes) for the SCCD group (P < .001). Hospital stay was significantly shorter for the RCD group with an average of 5 days (SD, 2 days) compared with 9 days (SD, 6 days) for the SCCD cohort (P < .0001). Cranial nerve deficit occurred in 17 patients, consisting of six transient nerve palsies in the RCD cohort and 11 in the SCCD group. Postoperative cerebrovascular accidents occurred in three patients in the SCCD cohort, with none observed in the RCD group. This translates into a rate of 22% of postoperative neurologic complications for the RCD cohort and 34% in the SCCD group (P < .08). Significant differences in intraoperative vascular injuries were not observed. The RCD technique is a safe and viable option for the surgical resection of CBTs. In our experience

  2. Properties of a transient K+ current in chemoreceptor cells of rabbit carotid body.

    PubMed Central

    López-López, J R; De Luis, D A; Gonzalez, C

    1993-01-01

    1. Adult rabbit carotid body chemoreceptor cells, enzymatically dispersed and short-term cultured, exhibit an inactivating outward K+ current that is reversibly inhibited by low PO2. In the present work we have characterized the biophysical and pharmacological properties of this current using the whole-cell voltage clamp recording technique. 2. Inactivating current was recorded after blockage of Ca2+ currents with extracellular Co2+, Cd2+, or after complete washing out of Ca2+ channels. 3. The threshold of activation of this inactivating current was about -40 mV. Current activated very quickly (mean rise time 4.8 +/- 0.42 ms at +60 mV) but inactivated more slowly. Inactivation was well fitted by two exponentials with time constants of 79.7 +/- 6.6 and 824 +/- 42.8 ms (at +40 mV). The inactivation process showed a little voltage dependence. 4. The steady-state inactivation was well fitted by a Boltzman function. Inactivation was fully removed at potentials negative to -80 mV and was complete at voltages near -10 mV; 50% inactivation occurred at -41 mV. 5. Recovery from inactivation had several components and was voltage dependent. Initial recovery was fast, but full recovery, even at -100 mV, required more than 30 s. 6. Inactivating current was selectively blocked by 4-aminopyridine (4-AP), in a dose-dependent manner (IC50, 0.2 mM). The duration of chemoreceptor cells action potentials was augmented by 1 mM 4-AP from 2.3 +/- 0.36 to 7.0 +/- 0.25 ms at 0 mV. Tetraethylamonium (TEA), at concentrations above 5 mM, blocked inactivating and non-inactivating components of the whole K+ current. 7. Inactivating current was modulated by cyclic AMP (cAMP). Bath application of 2 mM dibutyryl cAMP reduced peak amplitude by 18.7 +/- 2.9% (at +30 mV) and slowed down the rise time of the current. The effect was not voltage dependent. Forskolin (10-20 microM) also affected inactivating current, by accelerating the inactivation process. In the same preparations neither dibutyryl c

  3. Respiratory Adaptation to Acute Metabolic Acidosis in Goats with Ablated Carotid Bodies,

    DTIC Science & Technology

    1982-06-03

    values. DISCUSSION We have shown in a previous communication (26) that the goats used in the present study were deprived of peripheral chemoreception ...was manifest in the chemodenervated awake goats. This is in agreement with findings in anesthetized cats (14) and in anesthetized (12) and awake dogs...anesthetized cats by Katsaros (14). It appears that a respiratory adaptation to AMA, mani- fest in lowering the resting PaCO 2 and in shifting CO2

  4. Successful surgical management of a perforating oesophageal foreign body in a cat.

    PubMed

    Cariou, Matthieu P L; Lipscomb, Victoria J

    2011-01-01

    CASE PRESENTATION AND SURGICAL INTERVENTION: a 3-year-old cat was presented with a recent history of dysphagia and intermittent regurgitation. Radiography revealed a bony oesophageal foreign body at the level of the thoracic inlet. Endoscopic retrieval was attempted but resulted in severe dyspnoea due to the development of pneumomediastinum, pneumothorax and subcutaneous emphysema secondary to perforation of the oesophageal wall. Immediate surgical exploration was carried out. Extensive necrosis of the oesophagus resulting from the presence of the foreign body led to a decision to perform an oesophageal resection and anastomosis. this is the first clinical report of a cat treated successfully by oesophagectomy following oesophageal perforation due to an obstructive foreign body. The authors suggest that prompt surgical intervention, the ability to convert to a surgical procedure under the same anaesthetic as a non-surgical retrieval, placement of a gastrostomy tube and the availability of advanced anaesthetic and critical care support are important factors to consider when managing feline patients with a perforating oesophageal foreign body.

  5. The XY Body of the Cat (Felis catus): Structural Differentiations and Protein Immunolocalization.

    PubMed

    Sciurano, Roberta B; De Luca, Geraldine; Rahn, I Mónica; Solari, Alberto J

    2017-01-01

    The heteromorphic X and Y chromosomes behave in a special way in mammalian spermatocytes; they form the XY body and synapse only partially. The aim of this article was to study the origin and the role of the special differentiations in the XY pair of the domestic cat during pachytene by analyzing its fine structural characteristics and the immunolocalization of the main meiotic proteins SYCP3, SYCP1, SYCE3, SMC3, γ-H2AX, BRCA1, H3K27me3, and MLH1. The cat XY body shows particularly striking structures: an extreme degree of axial fibrillation in late pachynema and a special location of SYCP3-containing fibrils, bridging different regions of the main X axis, as well as one bridge at the inner end of the pairing region that colocalizes with the single mandatory MLH1 focus. There are sequential changes, first bullous expansions, then subdivision into fibrils, all involving axial thickening. The chromatin of the XY body presents the usual features of meiotic sex chromosome inactivation. An analysis of the XY body of many eutherians and metatherians suggests that axial thickenings are primitive features. The sequential changes in the mass and location of SYCP3-containing fibers vary among the clades because of specific processes of axial assembly/disassembly occurring in different species. © 2017 S. Karger AG, Basel.

  6. Can increased visceral adiposity without body weight changes accelerate carotid atherosclerosis in South Korean participants with type 2 diabetes?

    PubMed

    Kim, Chul Sik; Kim, Soo-Kyung; Araneta, Maria Rosario G; Lee, Eun Jig; Barrett-Connor, Elizabeth; Huh, Kab Bum

    2015-01-01

    Type 2 diabetes mellitus (T2DM) and visceral obesity are associated with each other and with cardiovascular diseases. We determined whether increased visceral adiposity without weight gain was associated with sex-specific accelerated carotid atherosclerosis in South Koreans with T2DM. From 2003 to 2012, we recruited 280 participants with T2DM for the Seoul Metabolic Syndrome cohort who had body weight, visceral fat thickness (VFT), and carotid intima-media thickness (CIMT) measured at intervals of 2years. According to VFT change, sex-specific quartiles of clinical characteristics and changes of CIMT were determined. Logistic regression models predicted the odds of the progression of CIMTs in each quartile. During 2years of observation, VFTs fell by 5.2±13.5mm in men (P<0.001) and 3.4±10.5mm in women (P<0.001). Progression of CIMT was only significant for women's maximal CIMT (0.031±0.145mm, P=0.012), while significant improvements in HbA1c were found (0.9%; P<0.001 in both sexes). There were no significant differences in clinical characteristics, or in progression of CIMT in men or women according to 2-year quartiles of VFT change. Our results do not suggest that increased visceral adiposity without body weight changes impacts the CIMT progression in South Korean men or women with T2DM. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. K+ channels in O2 sensing and postnatal development of carotid body glomus cell response to hypoxia

    PubMed Central

    Kim, Donghee

    2016-01-01

    The sensitivity of carotid body chemoreceptors to hypoxia is low just after birth and increases over the first few weeks of the postnatal period. At present, it is believed that the hypoxia-induced excitation of carotid body glomus cells begins with the inhibition of the outward K+ current via one or more O2 sensors. Although the nature of the O2 sensors and their signals that inhibit the K+ current are not well defined, studies suggest that the postnatal maturation of the glomus cell response to hypoxia is largely due to the increased sensitivity of K+ channels to hypoxia. As KV, BK and TASK channels that are O2-sensitive contribute to the K+ current, it is important to identify the O2 sensor and the signaling molecule for each of these K+ channels. Various O2 sensors (mitochondrial hemeprotein, hemeoxygenase-2, NADPH oxidase) and associated signals have been proposed to mediate the inhibition of K+ channels by hypoxia. Studies suggest that a mitochondrial hemeprotein is likely to serve as an O2 sensor for K+ channels, particularly for TASK, and that multiple signals may be involved. Thus, changes in the sensitivity of the mitochondrial O2 sensor to hypoxia, the sensitivity of K+ channels to signals generated by mitochondria, and/or the expression levels of K+ channels are likely to account for the postnatal maturation of O2 sensing by glomus cells. PMID:22801091

  8. Lower body positive pressure application with an antigravity suit in acute carotid occlusion.

    PubMed

    Berthet, Karine; Lukaszewicz, Anne Claire; Bousser, Marie-Germaine; Payen, Didier

    2010-04-01

    The challenge in acute stroke is still to reperfuse as early as possible the ischemic territory. Since fibrinolytic therapies have a limited window with potential risk of bleeding, having a nonpharmacologic mean to recruit vessels in area surrounding necrosis might be useful. We propose here to use antigravity suit inflated at "venous" pressure levels to shift blood towards thoracic and brain territories. We report two cases of spectacular clinical recovery after acute carotid occlusion.

  9. The effect of discrete stimulation of carotid body chemoreceptors on atrial natriuretic peptide in anaesthetized dogs.

    PubMed Central

    al-Obaidi, M; Whitaker, E M; Karim, F

    1991-01-01

    1. In seven chloralose-anaesthetized and artificially ventilated beagles, the carotid sinus regions were vascularly isolated and perfused with either arterial or mixed (arterial and venous) blood (PO2 46.4 +/- 1.5 mmHg, mean +/- S.E.M.) to stimulate the chemoreceptors at constant flow and pressure. Cervical vagosympathetic trunks were ligated in all dogs, and gallamine triethiodide (2.0 mg kg-1 h-1, I.V.) was given in five dogs. Right atrial pressure was measured in all dogs, and left atrial pressure in four dogs. Mean aortic pressure was held constant (91.0 +/- 3.0 mmHg) by means of a reservoir connected to the animal via the common carotid and femoral arteries. Plasma atrial natriuretic peptide (ANP) was measured by radioimmunoassay and urinary sodium by flame photometry. 2. In seven dogs with mean carotid sinus pressure maintained at 96.0 +/- 4.3 mmHg, stimulation of the carotid chemoreceptors for 25 min produced significant increases in left atrial pressure of 41.2 +/- 3.3% (n = 4; P less than 0.005) from 5.4 +/- 0.6 cmH2O and of 30.9 +/- 4.5% (n = 7; P less than 0.002) in ANP from 31.6 +/- 2.1 pg ml-1. However, chemoreceptor stimulation produced significant decreases in urine flow rate of 26.1 +/- 1.9% (n = 9; P less than 0.001) from 0.29 +/- 0.03 ml min-1 (100 g kidney weight)-1 and sodium excretion of 29.0 +/- 2.3% (P less than 0.001) from 8.5 +/- 1.7 mumol min-1 (100 g kidney weight)-1 but right atrial pressure and heart rate did not change significantly. In three of the dogs, beta-adrenoceptor blockade by atenolol (2 mg kg-1, I.V.) greatly reduced the effects of chemoreceptor stimulation on plasma levels of ANP. 3. The results show, for the first time, that discrete stimulation of the carotid chemoreceptors caused an increase in plasma ANP levels, probably due to the reflex increase in atrial pressure that results from an inhibition of the cardiac sympathetic nerves, and an increase in venous return from a reduction of peripheral vascular capacitance. PMID

  10. Increased age, high body mass index and low HDL-C levels are related to an echolucent carotid intima-media: the METEOR study.

    PubMed

    Peters, S A E; Lind, L; Palmer, M K; Grobbee, D E; Crouse, J R; O'Leary, D H; Evans, G W; Raichlen, J; Bots, M L; den Ruijter, H M

    2012-09-01

    Echolucent plaques are related to a higher cardiovascular risk. Studies to investigate the relationship between echolucency and cardiovascular risk in the early stages of atherosclerosis are limited. We studied the relationship between cardiovascular risk factors and echolucency of the carotid intima-media in low-risk individuals. Data were analysed from the Measuring Effects on Intima-Media Thickness: an Evaluation of Rosuvastatin (METEOR) study, a randomized placebo-controlled trial including 984 individuals which showed that rosuvastatin attenuated the rate of change of carotid intima-media thickness (CIMT). In this post hoc analysis, duplicate baseline ultrasound images from the far wall of the left and right common carotid arteries were used for the evaluation of the echolucency of the carotid intima-media, measured by grey-scale median (GSM) on a scale of 0-256. Low GSM values reflect echolucent, whereas high values reflect echogenic structures. The relationship between baseline GSM and cardiovascular risk factors was evaluated using linear regression models. Mean baseline GSM (± SD) was 84 ± 29. Lower GSM of the carotid intima-media was associated with older age, high body mass index (BMI) and low levels of high-density lipoprotein cholesterol (HDL-C) [beta -4.49, 95% confidence interval (CI) -6.50 to -2.49; beta -4.51, 95% CI -6.43 to -2.60; beta 2.45, 95% CI 0.47 to 4.42, respectively]. Common CIMT was inversely related to GSM of the carotid intima-media (beta -3.94, 95% CI -1.98 to -5.89). Older age, high BMI and low levels of HDL-C are related to echolucency of the carotid intima-media. Hence, echolucency of the carotid intima-media may be used as a marker of cardiovascular risk profile to provide more information than thickness alone. © 2012 The Association for the Publication of the Journal of Internal Medicine.

  11. Original report of bilateral carotid body tumors with 2 rare concomitant anatomic findings, an ectopic parathyroid gland and cervical thymus, with literature review.

    PubMed

    Westbrook, Benjamin J; Harsha, Wayne J; Strenge, Karen

    2013-03-01

    Carotid body tumors are uncommon neoplasms with unique epidemiology and management demands. Cervical embryology is complex. Developmental abnormalities can result in ectopic displacement of native tissues. We present the case of a 21-year-old female with bilateral carotid body paragangliomas who presented to our clinic seeking excision of the symptomatic right-sided tumor. The patient was successfully treated with surgical excision. Two rare anatomic variants were identified in her surgical specimen: a carotid sheath parathyroid gland and ectopic thymus tissue. This patient represents an unreported combination of pathologic and anatomic phenomena. The paraganglioma resulted from a familial genetic mutation that is well studied in this patient's ethnic population (Dutch), and the literature on this topic is reviewed herein. The 2 anatomic variants likely represent a single, embryologic glitch that will carry no physiologic sequelae. The clinical application of this ectopic anatomy and the common embryologic origins are discussed. Copyright © 2011 Wiley Periodicals, Inc.

  12. A Short-Term Fasting in Neonates Induces Breathing Instability and Epigenetic Modification in the Carotid Body.

    PubMed

    Shirahata, Machiko; Tang, Wan-Yee; Kostuk, Eric W

    2015-01-01

    The respiratory control system is not fully developed in newborn, and data suggest that adequate nutrition is important for the development of the respiratory control system. Infants need to be fed every 2-4 h to maintain appropriate energy levels, but a skip of feeding can occur due to social economical reasons or mild sickness of infants. Here, we asked questions if a short-term fasting (1) alters carotid body (CB) chemoreceptor activity and integrated function of the respiratory control system; (2) causes epigenetic modification within the respiratory control system. Mouse pups (carotid sinus nerve activity appeared to be depressed after fasting. Moreover, fasting increased global 5mC and 5-hmC content in DNA isolated from the CB but not DNA in the superior cervical ganglion (SCG). Methylation specific PCR (MSPCR) revealed that fasting increased methylation of leptin and socs3 genes. The results suggest fasting inhibits CB activity leading to hypoventilation, and low glucose does not compensate the low CB activity. Epigenetic effect on CB function/activity may be related to the prolonged effect of fasting on ventilation.

  13. Tetrodotoxin as a Tool to Elucidate Sensory Transduction Mechanisms: The Case for the Arterial Chemoreceptors of the Carotid Body

    PubMed Central

    Rocher, Asuncion; Caceres, Ana Isabel; Obeso, Ana; Gonzalez, Constancio

    2011-01-01

    Carotid bodies (CBs) are secondary sensory receptors in which the sensing elements, chemoreceptor cells, are activated by decreases in arterial PO2 (hypoxic hypoxia). Upon activation, chemoreceptor cells (also known as Type I and glomus cells) increase their rate of release of neurotransmitters that drive the sensory activity in the carotid sinus nerve (CSN) which ends in the brain stem where reflex responses are coordinated. When challenged with hypoxic hypoxia, the physiopathologically most relevant stimulus to the CBs, they are activated and initiate ventilatory and cardiocirculatory reflexes. Reflex increase in minute volume ventilation promotes CO2 removal from alveoli and a decrease in alveolar PCO2 ensues. Reduced alveolar PCO2 makes possible alveolar and arterial PO2 to increase minimizing the intensity of hypoxia. The ventilatory effect, in conjunction the cardiocirculatory components of the CB chemoreflex, tend to maintain an adequate supply of oxygen to the tissues. The CB has been the focus of attention since the discovery of its nature as a sensory organ by de Castro (1928) and the discovery of its function as the origin of ventilatory reflexes by Heymans group (1930). A great deal of effort has been focused on the study of the mechanisms involved in O2 detection. This review is devoted to this topic, mechanisms of oxygen sensing. Starting from a summary of the main theories evolving through the years, we will emphasize the nature and significance of the findings obtained with veratridine and tetrodotoxin (TTX) in the genesis of current models of O2-sensing. PMID:22363245

  14. Titmouse calling and foraging are affected by head and body orientation of cat predator models and possible experience with real cats.

    PubMed

    Book, D L; Freeberg, Todd M

    2015-09-01

    Although anti-predator behavior systems have been studied in diverse taxa, less is known about how prey species detect and assess the immediate threat posed by a predator based on its behavior. In this study, we evaluated a potential cue that some species may utilize when assessing predation threat-the predator's body and head orientation. We tested the effect of this orientation cue on signaling and predation-risk-sensitive foraging of a prey species, tufted titmice (Baeolophus bicolor). Earlier work revealed sensitivity of titmice and related species to the presence of predator stimuli. Here, we manipulated cat models to face either toward or away from a food source preferred by titmice and then measured titmouse calling and seed-taking behavior. Titmice showed greater feeder avoidance when the cat predator models faced the feeder, compared to when the models faced away from the feeder or when titmice were exposed to control stimuli. Titmouse calling was also sensitive to predator head/body orientation, depending upon whether titmice were from sites where real cats had been observed or not. This study experimentally demonstrated that both calling and foraging of prey species can be affected by the head and body orientation of an important terrestrial predator. Prey species may therefore signal in strategic ways to conspecifics not just about predator presence, but also urgency of threat related to the more subtle cue of the head and body orientation of the predator. These findings hold potential implications for understanding animal cognition and learning processes.

  15. Compatibility of imported fire ant whole body extract with cat, ragweed, Dermatophagoides pteronyssinus, and timothy grass allergens.

    PubMed

    Rans, Tonya S; Hrabak, Todd M; Whisman, Bonnie A; Grier, Thomas J; LeFevre, Dawn M; Kwon, Paul O; Tankersley, Michael S

    2009-01-01

    Recommendations regarding the administration of imported fire ant whole body extract (IFA WBE) combined with aeroallergens or environmental allergens in a single immunotherapy injection are lacking. To evaluate the degradative effect of IFA WBE on cat, ragweed, Dermatophagoides pteronyssinus, and timothy grass allergens. Imported fire ant whole body extract was combined with extracts of cat, ragweed, D pteronyssinus, and timothy grass. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed on each sample after storage for 0, 1, 3, and 6 months at 4 degrees C. In addition, cat and ragweed combinations were evaluated by radial immunodiffusion (RID); D pteronyssinus by enzyme-linked immunosorbent assay (ELISA) inhibition; and timothy grass by ELISA inhibition and Western blot. Imported fire ant whole body extract combined with timothy grass demonstrated degradation of timothy grass allergens by SDS-PAGE, ELISA inhibition, and Western blot results. Cat and ragweed allergens were stable after mixing with IFA WBE, based on SDS-PAGE and RID analyses. Stability of D pteronyssinus allergens with IFA WBE was evident from SDS-PAGE and ELISA inhibition data. Imported fire ant whole body extract combined with timothy grass resulted in significant and rapid timothy protein degradation. Imported fire ant whole body extract mixed with cat, ragweed, or D pteronyssinus revealed aeroallergen stability, yielding the possibility of combining these extracts in a single immunotherapy injection. Compatibilities of IFA WBE with other common aeroallergens remain undetermined and thus are not recommended for single-injection immunotherapy formulations.

  16. Carotid labyrinth of amphibians.

    PubMed

    Kusakabe, Tatsumi

    2002-11-01

    - and baroreceptor functions analogous to those of the mammalian carotid body and carotid sinus. The ultrastructural characteristics of the glomus cells during and after metamorphosis suggest that the glomus cells contribute to the chemoreception after metamorphosis. The three-dimensional fine structure of vascular corrosion casts suggests that the amphibian carotid labyrinth has the appropriate architecture for controlling vascular tone and the findings throughout metamorphosis reveal that the vascular regulatory function begins at an early stage of metamorphosis. In addition, immunohistochemical studies suggest that the vascular regulation in the carotid labyrinth is under peptidergic innervation. Thus, the multiple functions of the carotid labyrinth underline the importance of this relatively small organ for maintenance of homeostasis and appropriate blood supply to the cephalic region.

  17. CO(2) and pH independently modulate L-type Ca(2+) current in rabbit carotid body glomus cells.

    PubMed

    Summers, Beth A; Overholt, Jeffrey L; Prabhakar, Nanduri R

    2002-08-01

    The carotid bodies respond to changes in arterial O(2), CO(2), and pH, and Ca(2+) influx via voltage-gated Ca(2+) channels is an important step in the chemoreception process. The objectives of the present study were as follows: 1) to determine whether hypercapnia modulates Ca(2+) current in glomus cells, and if so, to determine if this modulation is secondary to changes in pH; 2) to examine the mechanism of CO(2) modulation of the Ca(2+) current; and 3) to determine whether the effects of hypercapnia and hypoxia on Ca(2+) channel activity in glomus cells are synergistic. The effects of CO(2) on Ca(2+) current were monitored in glomus cells isolated from rabbit carotid bodies using both perforated and conventional patch-clamp techniques. Raising CO(2) in the extracellular solution from 5 to 10% (hypercapnia) reversibly augmented the whole-cell Ca(2+) current. This augmentation was rapid and increased the whole-cell Ca(2+) current similarly in both the perforated and the conventional patch configurations by 16 +/- 2% (n = 5) and 15 +/- 1% (n = 32), respectively. The following observations suggest that the effects of CO(2) are not secondary to changes in pH: 1) isohydric hypercapnia (pH maintained at 7.4) augmented the Ca(2+) current by 24 +/- 2% (n = 6); 2) decreasing the pH of the extra- or intracellular solutions decreased the Ca(2+) current by 43 +/- 4% (n = 8) and 13 +/- 1% (n = 5), respectively; and 3) hypercapnia did not shift the half-maximal activation voltage (V(1/2)), whereas intracellular and extracellular acidosis alone caused shifts in V(1/2). Furthermore, 100 nM of a membrane-permeable protein kinase A inhibitor prevented the augmentation by CO(2), and 500 microM 8-Br-cAMP mimicked the effect of CO(2) by augmenting the Ca(2+) current by 10 +/- 2% (n = 6). Also, cyclic AMP levels in carotid bodies increased from 1.98 +/- 0.6 to 9.0 +/- 2 pmol/microg protein in response to hypercapnia. In contrast, decreasing pH in the nominal absence of CO(2) did not

  18. Peripheral chemoreceptors determine the respiratory sensitivity of central chemoreceptors to CO2: role of carotid body CO2

    PubMed Central

    Smith, Curtis A; Blain, Grégory M; Henderson, Kathleen S; Dempsey, Jerome A

    2015-01-01

    Abstract We asked if the type of carotid body (CB) chemoreceptor stimulus influenced the ventilatory gain of the central chemoreceptors to CO2. The effect of CB normoxic hypocapnia, normocapnia and hypercapnia (carotid body  ≈ 22, 41 and 68 mmHg, respectively) on the ventilatory CO2 sensitivity of central chemoreceptors was studied in seven awake dogs with vascularly-isolated and extracorporeally-perfused CBs. Chemosensitivity with one CB was similar to that in intact dogs. In four CB-denervated dogs, absence of hyper-/hypoventilatory responses to CB perfusion with of 19–75 mmHg confirmed separation of the perfused CB circulation from the brain. The group mean central CO2 response slopes were increased 303% for minute ventilation ()(P ≤ 0.01) and 251% for mean inspiratory flow rate (VT/TI) (P ≤ 0.05) when the CB was hypercapnic vs. hypocapnic; central CO2 response slopes for tidal volume (VT), breathing frequency (fb) and rate of rise of the diaphragm EMG increased in 6 of 7 animals but the group mean changes did not reach statistical significance. Group mean central CO2 response slopes were also increased 237% for (P ≤ 0.01) and 249% for VT/TI(P ≤ 0.05) when the CB was normocapnic vs. hypocapnic, but no significant differences in any of the central ventilatory response indices were found between CB normocapnia and hypercapnia. These hyperadditive effects of CB hyper-/hypocapnia agree with previous findings using CB hyper-/hypoxia.We propose that hyperaddition is the dominant form of chemoreceptor interaction in quiet wakefulness when the chemosensory control system is intact, response gains physiological, and carotid body chemoreceptors are driven by a wide range of O2 and/or CO2. Key points The influence of specific carotid body (CB) normoxic hypocapnia, hypercapnia and normocapnia on the ventilatory sensitivity of central chemoreceptors to systemic hypercapnia was assessed in seven awake dogs with extracorporeal perfusion of the

  19. Measurement of body composition in cats using computed tomography and dual energy X-ray absorptiometry.

    PubMed

    Buelund, Lene E; Nielsen, Dorte H; McEvoy, Fintan J; Svalastoga, Eiliv L; Bjornvad, Charlotte R

    2011-01-01

    Dual energy X-ray absorptiometry (DEXA) is a reference method for assessing body composition but is seldom `accessible in veterinary settings. Computed tomography (CT) can provide similar body composition estimates and we propose that it can be used in body composition studies in animals. We compared CT and DEXA data from 73 healthy adult neutered domestic cats. Three approaches for measuring adipose tissue percentage from full-body CT scans were explored. By examining the frequency distribution of voxels by Hounsfield unit (HU) value, it is possible to calculate a fat index (Fat%) that is in close agreement with the fat percentages obtained from DEXA scans. Fat% values obtained by the best of the methods had a mean difference of 0.96% (95% confidence interval 0.33-1.59%) from the DEXA results. Fat% obtained by the other two methods were characterized by good correlation but poor agreement and in one of the methods, the difference between the values from the two modalities was proportional to their mean. By using CT, it is possible to obtain body composition estimates that are in close agreement with those available using DEXA. While the significance of individual Fat% measurements obtained from CT can be difficult to interpret and to compare between centers, CT can contribute to research studies concerned either with nutrition or with obesity-related disorders.

  20. The respiratory response to carbon dioxide in humans with unilateral and bilateral resections of the carotid bodies

    PubMed Central

    Fatemian, Marzieh; Nieuwenhuijs, Diederik J F; Teppema, Luc J; Meinesz, Sietske; van der Mey, Andel G L; Dahan, Albert; Robbins, Peter A

    2003-01-01

    The acute hypercapnic ventilatory response (AHCVR) arises from both peripheral and central chemoreflexes. In humans, one technique for identifying the separate contributions of these chemoreflexes to AHCVR has been to associate the rapid component of AHCVR with the peripheral chemoreflex and the slow component with the central chemoreflex. Our first aim was to validate this technique further by determining whether a single slow component was sufficient to describe AHCVR in patients with bilateral carotid body resections (BR) for glomus cell tumours. Our second aim was to determine whether the slow component of AHCVR was diminished following carotid body resection as has been suggested by studies in experimental animals. Seven BR subjects were studied together with seven subjects with unilateral resections (UR) and seven healthy controls. A multifrequency binary sequence in end-tidal PCO2 was employed to stimulate ventilation dynamically under conditions of both euoxia and mild hypoxia. Both two- and one-compartment models of AHCVR were fitted to the data. For BR subjects, the two-compartment model fitted significantly better on 1 out of 13 occasions compared with 22 out of 28 occasions for the other subjects. Average values for the chemoreflex sensitivity of the slow component of AHCVR differed significantly (P < 0.05) between the groups and were 0.95, 1.38 and 1.50 l min−1 Torr−1 for BR, UR and control subjects, respectively. We conclude that, without the peripheral chemoreflex, AHCVR is adequately described by a single slow component and that BR subjects have sensitivities for the slow component that are lower than those of control subjects. PMID:12717011

  1. Carotid Ultrasound

    MedlinePlus

    ... this page from the NHLBI on Twitter. Carotid Ultrasound Also known as carotid duplex. Carotid ultrasound is a painless imaging test that uses high- ... of your carotid arteries. This test uses an ultrasound machine, which includes a computer, a screen, and ...

  2. In the carotid body, galanin is a signal for neurogenesis in young, and for neurodegeneration in the old and in drug-addicted subjects.

    PubMed

    Mazzatenta, Andrea; Marconi, Guya D; Zara, Susi; Cataldi, Amelia; Porzionato, Andrea; Di Giulio, Camillo

    2014-01-01

    The carotid body is a highly specialized chemoreceptive structure for the detection of and reaction to hypoxia, through induction of an increase in hypoxia inducible factor. As tissue hypoxia increases with aging and can have dramatic effects in respiratory depression induced by drug addiction, we investigated the carotid body in young and old healthy subjects in comparison with drug-addicted subjects, including the expression of the neurotransmitter galanin. Galanin expression was recently reported for neuronal-like cells of the human carotid body, and it is implicated in several functions in neurons. In particular, this includes the regulation of differentiation of neural stem cells, and participation in the development and plasticity of the nervous system. Using immunohistochemistry detection, we demonstrate that galanin expression in the human carotid body in healthy older subjects and drug-addicted subjects is significantly reduced in comparison with healthy young subjects. This demonstrates not only the effects of normal aging and senescence, but also in the drug-addicted subjects, this appears to be due to a disorganization of the chemo-sensory region. With both aging and drug addiction, this results in a physiological reduction in neuronal-like cells, coupled with interlobular and intralobular increases in connective tissue fibers. Consequently, in both aging and drug addiction, this reduction of neuronal-like cells and the regeneration suggest that the carotid body is losing its sensory capabilities, with the transmission of chemoreceptive signals dramatically and vitally reduced. The level of galanin expression would thus provide a signal for neurogenesis in young subjects, and for neurodegeneration in older and drug-addicted subjects.

  3. Usefulness of acute phase proteins in differentiating between feline infectious peritonitis and other diseases in cats with body cavity effusions.

    PubMed

    Hazuchova, Katarina; Held, Susanne; Neiger, Reto

    2017-08-01

    Objectives The aim of this study was to evaluate the measurement of acute phase proteins (APPs) as a diagnostic tool to differentiate between feline infectious peritonitis (FIP) and other diseases in cats with body cavity effusions. Methods Cats with pleural, abdominal or pericardial effusion were prospectively enrolled. Cats were classified as having or not having FIP based on immunohistochemistry (if available) or a sophisticated statistical method using machine learning methodology with concepts from game theory. Cats without FIP were further subdivided into three subgroups: cardiac disease, neoplasia and other diseases. Serum amyloid A (SAA), haptoglobin (Hp) and α1-acid glycoprotein (AGP) were measured in serum and effusion, using assays previously validated in cats. Results Serum and effusion samples were available for the measurement of APPs from 88 and 67 cats, respectively. Concentrations of the APPs in serum and effusion were significantly different in cats with and without FIP ( P <0.001 for all three APPs). The best APP to distinguish between cats with and without FIP was AGP in the effusion; a cut-off value of 1550 µg/ml had a sensitivity and specificity of 93% each for diagnosing FIP. Conclusions and relevance AGP, particularly if measured in effusion, was found to be useful in differentiating between FIP and other diseases, while SAA and Hp were not. The concentration of all three APPs in some diseases (eg, septic processes, disseminated neoplasia) was as high as in cats with FIP; therefore, none of these can be recommended as a single diagnostic test for FIP.

  4. Morphological differences of the carotid body among C57/BL6 (B6), A/J, and CSS B6A1 mouse strains.

    PubMed

    Chai, Sam; Gillombardo, Carl B; Donovan, Lucas; Strohl, Kingman P

    2011-08-15

    The C57/BL6 (B6) mouse strain exhibits post-hypoxic frequency decline and periodic breathing, as well as greater amount of irregular breathing during rest in comparison to the A/J and to the B6a1, a chromosomal substitution strain whereby the A/J chromosome 1 is bred onto the B6 background (Han et al., 2002; Yamauchi et al., 2008a,b). The hypothesis was that morphological differences in the carotid body would associate with such trait variations. After confirming strain differences in post-hypoxic ventilatory behavior, histological examination (n=8 in each group) using hematoxylin and eosin (H&E) staining revealed equivalent, well-defined tissue structure at the bifurcation of the carotid arteries, an active secretory parenchyma (type I cells) from the supportive stromal tissue, and clustering of type I cells in all three strains. Tyrosine hydroxylase (TH) immunohistochemical staining revealed a typical organization of type I cells and neurovascular components into glomeruli in all three strains. Image analysis from 5 μm sections from each strain generated a series of cytological metrics. The percent carotid body composition of TH+ type I cells in the A/J, B6 and B6a1 was 20±4%, 39±3%, and 44±3%, respectively (p=0.00004). However, cellular organization in terms of density and ultrastructure in the B6a1 is more similar to the B6 than to the A/J. These findings indicate that genetic mechanisms that produce strain differences in ventilatory function do not associate with carotid body structure or tyrosine hydroxylase morphology, and that A/J chromosome 1 does not contribute much to B6 carotid body morphology.

  5. Chronic caffeine intake in adult rat inhibits carotid body sensitization produced by chronic sustained hypoxia but maintains intact chemoreflex output.

    PubMed

    Conde, Silvia V; Ribeiro, Maria J; Obeso, Ana; Rigual, Ricardo; Monteiro, Emilia C; Gonzalez, Constancio

    2012-12-01

    Sustained hypoxia produces a carotid body (CB) sensitization, known as acclimatization, which leads to an increase in carotid sinus nerve (CSN) activity and ensuing hyperventilation greater than expected from the prevailing partial pressure of oxygen. Whether sustained hypoxia is physiological (high altitude) or pathological (lung disease), acclimatization has a homeostatic implication because it tends to minimize hypoxia. Caffeine, the most commonly ingested psychoactive drug and a nonselective adenosine receptor antagonist, alters CB function and ventilatory responses when administered acutely. Our aim was to investigate the effect of chronic caffeine intake on CB function and acclimatization using four groups of rats: normoxic, caffeine-treated normoxic, chronically hypoxic (12% O₂, 15 days), and caffeine-treated chronically hypoxic rats. Caffeine was administered in drinking water (1 mg/ml). Caffeine ameliorated ventilatory responses to acute hypoxia in normoxic animals without altering the output of the CB (CSN neural activity). Caffeine-treated chronically hypoxic rats exhibited a decrease in the CSN response to acute hypoxia tests but maintained ventilation compared with chronically hypoxic animals. The findings related to CSN neural activity combined with the ventilatory responses indicate that caffeine alters central integration of the CB input to increase the gain of the chemoreflex and that caffeine abolishes CB acclimatization. The putative mechanisms involved in sensitization and its loss were investigated: expression of adenosine receptors in CB (A(2B)) was down-regulated and that in petrosal ganglion (A(2A)) was up-regulated in caffeine-treated chronically hypoxic rats; both adenosine and dopamine release from CB chemoreceptor cells was increased in chronic hypoxia and in caffeine-treated chronic hypoxia groups.

  6. Subcutaneous hemangiosarcoma induced by a foreign body (steel staple) in a cat.

    PubMed

    Tan, Rommel Max; Singh, Kuldeep; Sandman, Kristi

    2013-04-01

    An 8-year-old, female domestic shorthair cat was presented with a ventral abdominal subcutaneous mass. A radiograph showed that the center of the mass contained what appeared to be steel sutures, presumed to be from an ovariohysterectomy performed 7 years earlier. The excised mass was irregular and contained numerous pockets filled with friable necrotic material and hemorrhages that were dissected by fibrous connective tissue bands. Multiple tangled and fragmented pieces of steel staples were deeply embedded within the mass. Histologically, the mass was non-encapsulated, densely cellular, and infiltrative. Neoplastic cells lined caverns and channels and were factor VIII-positive by immunohistochemistry. The neoplastic cells were oval to round with granular cytoplasm and vesicular nucleus and exhibited moderate cellular and nuclear pleomorphism. A diagnosis of subcutaneous hemangiosarcoma was made. To our knowledge, this is the first report of foreign body associated hemangiosarcoma and the first case of steel staple associated neoplasm in domestic animals.

  7. Differential modulation by extracellular ATP of carotid chemosensory responses.

    PubMed

    Spergel, D; Lahiri, S

    1993-06-01

    The possibility that the carotid body has ATP surface receptors that mediate O2 chemoreception was tested. To distinguish between the event(s) initiating chemoreception and those at the neurotransmitter level, we also tested the chemosensory response to nicotine before and after ATP administration. Carotid bodies from cats anesthetized with pentobarbital sodium were perfused and superfused in vitro with modified Tyrode solution (PCO2 < 1 Torr, pH 7.4, 36 degrees C) equilibrated at PO2 > 400 or approximately 150 Torr while chemosensory discharge was recorded extracellularly. ATP and adenosine 5'-[gamma-thio]triphosphate stimulated discharge with similar dose dependence, whereas adenosine had little effect. ATP infusion for > or = 2 min evoked an initial stimulation of discharge followed by a decline to baseline (desensitization). Desensitization did not affect the response to hypoxia (perfusate flow interruption) but inhibited the response to nicotine (4-nmol pulse). Therefore, 1) the carotid body has surface ATP receptors that may mediate the chemosensory response to nicotine but not to hypoxia and 2) nicotinic receptors are not required for carotid body O2 chemoreception.

  8. Biphasic changes in body temperature produced by intracerebroventricular injections of histamine in the cat.

    PubMed

    Clark, W G; Cumby, H R

    1976-09-01

    1. Intracerebroventricular administration of histamine to cats caused hypothermia followed by a rise in body temperature. 2-Methylhistamine caused a similar biphasic response, while 3-methylhistamine had no effect on body temperature and 4-methylhistamine produced a delayed hyperthermia. Some tolerance to the hypothermic activity developed when a series of closely spaced injections of histamine was given. 2. Doses of histamine and 2-methylhistamine which altered body temperature when given centrally were ineffective when infused or injected I.V. 3. Pyrilamine, an H1-receptor antagonist, prevented the hypothermic response to histamine. 4. Hypothermic responses to histamine at an environmental temperature of 22 degrees C were comparable to responses in a cold room at 4 degrees C in both resting animals and animals acting to depress a lever to escape an external heat load. A change in error signal from the thermostat could account for these results. However, lesser degrees of hypothermia developed when histamine was given to animals in a hot environment. In some, but not all animals, this smaller response could be attributed to inadequate heat loss in spite of maximal activation of heat-loss mechanisms. 5. The hyperthermic response to histamine was antagonized by central, but not peripheral, injection of metiamide, an H2-receptor antagonist. 6. The results indicate that histamine and related agents can act centrally to cause both hypothermia, mediated by H1-receptors, and hyperthermia, mediated by H2-receptors.

  9. Effect of feeding a weight loss food beyond a caloric restriction period on body composition and resistance to weight gain in cats.

    PubMed

    Floerchinger, Amanda M; Jackson, Matthew I; Jewell, Dennis E; MacLeay, Jennifer M; Hahn, Kevin A; Paetau-Robinson, Inke

    2015-08-15

    To determine the effect of feeding a food with coconut oil and supplemental L-carnitine, lysine, leucine, and fiber on weight loss and maintenance in cats. Prospective clinical study. 50 overweight cats. The study consisted of 2 trials. During trial 1, 30 cats were allocated to 3 groups (10 cats/group) to be fed a dry maintenance cat food to maintain body weight (group 1) or a dry test food at the same amount on a mass (group 2) or energy (group 3) basis as group 1. During trial 2, each of 20 cats was fed the test food and caloric intake was adjusted to maintain a weight loss rate of 1%/wk (weight loss phase). Next, each cat was fed the test food in an amount calculated to maintain the body weight achieved at the end of the weight loss phase (weight maintenance phase). Cats were weighed and underwent dual-energy x-ray absorptiometry monthly. Metabolomic data were determined before (baseline) and after each phase. During trial 1, cats in groups 2 and 3 lost significantly more weight than did those in group 1. During trial 2, cats lost a significant amount of body weight and fat mass but retained lean body mass during the weight loss phase and continued to lose body weight and fat mass but gained lean body mass during the weight maintenance phase. Evaluation of metabolomic data suggested that fat metabolism was improved from baseline for cats fed the test food. Results suggested that feeding overweight cats the test food caused weight loss and improvements in body condition during the weight maintenance phase, possibly because the food composition improved energy metabolism.

  10. Carotid artery surgery

    MedlinePlus

    Carotid endarterectomy; CAS surgery; Carotid artery stenosis - surgery; Endarterectomy - carotid artery ... through the catheter around the blocked area during surgery. Your carotid artery is opened. The surgeon removes ...

  11. Human carotid body neuroglobin, vascular endothelial growth factor and inducible nitric oxide synthase expression in heroin addiction.

    PubMed

    Zara, S; Porzionato, A; De Colli, M; Macchi, V; Cataldi, A; De Caro, R; Di Giulio, C

    2013-07-01

    The carotid body (CB) represents the prime site for detecting and responding to hypoxia. Since the role of heroin in respiratory depression with consequent hypoxia is known, the authors were able to investigate morphological and molecular modifications occurring in the CB of heroin addicted subjects compared to subjects who died because of trauma. CB sampled from six 27 year old subjects, slides were treated with Mallory Trichrome staining or used for immunohistochemical analysis to detect Neuroglobin (NGB), Hypoxia Inducible Factor-1 (HIF-1α), Vascular Endothelial Growth Factor (VEGF), Inducible Nitric Oxide Synthase (i-NOS), Bax and cleaved Caspase-3 proteins. Mallory Trichrome staining shows an increase in the connective tissue in heroin subjects compared to controls and a parallel reduction in parenchymal area. Immunohistochemical analyses in heroin subjects found a decrease in NGB and an increase in HIF-1α and VEGF compared to controls; i-NOS expression was not statistically significant. Bax and cleaved caspase-3 were positive only in the heroin subjects. These results could confirm the typical hypoxic condition occurring in heroin addicts. Since NGB may function as a reactive oxygen or nitrogen species scavenger and as apoptotic cell death protector, the decrease in its expression may suggest a key role of this globin in human CB impairment due to heroin addiction.

  12. Changes in carotid body and nTS neuronal excitability following neonatal sustained and chronic intermittent hypoxia exposure.

    PubMed

    Mayer, C A; Wilson, C G; MacFarlane, P M

    2015-01-01

    We investigated whether pre-treatment with neonatal sustained hypoxia (SH) prior to chronic intermittent hypoxia (SH+CIH) would modify in vitro carotid body (CB) chemoreceptor activity and the excitability of neurons in the caudal nucleus of the solitary tract (nTS). Sustained hypoxia followed by CIH exposure simulates an oxygen paradigm experienced by extremely premature infants who developed persistent apnea. Rat pups were treated with 5 days of SH (11% O2) from postnatal age 1 (P1) followed by 10 days of subsequent chronic intermittent hypoxia (CIH, 5% O2/5 min, 8 h/day, between P6 and P15) as described previously (Mayer et al., Respir. Physiol. Neurobiol. 187(2): 167-75, 2013). At the end of SH+CIH exposure (P16), basal firing frequency was enhanced, and the hypoxic sensory response of single unit CB chemoafferents was attenuated. Further, basal firing frequency and the amplitude of evoked excitatory post-synaptic currents (ESPC's) of nTS neurons was augmented compared to age-matched rats raised in normoxia. These effects were unique to SH+CIH exposure as neither SH or CIH alone elicited any comparable effect on chemoafferent activity or nTS function. These data indicated that pre-treatment with neonatal SH prior to CIH exposure uniquely modified mechanisms of peripheral (CB) and central (nTS) neural function in a way that would be expected to disturb the ventilatory response to acute hypoxia.

  13. Interleukin-1β promotes the neurogenesis of carotid bodies by stimulating the activation of ERK1/2.

    PubMed

    Xue, Fen; Liu, Ling; Fan, Juan; He, ShanShan; Li, Rui; Peng, Zheng-Wu; Wang, Bai-Ren

    2015-12-01

    The carotid body (CB) is a complex sensory organ that functions to sense homeostatic O2 in the blood. Previous studies have shown that CBs express interleukin (IL)-1 receptor type I and that the chemosensitivity of CBs is increased following stimulation with pro-inflammatory cytokines. However, the effects of pro-inflammatory cytokines, such as IL-1β, on the neurogenesis of CB are unclear. Thus, in this study, we aimed to assess the effects of IL-1β and intermittent hypobaric hypoxia (IHH) plus IL-1β on the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, tyrosine hydroxylase (TH) and the expression of nestin, a well-established stem cell marker in the nervous system. The results showed that TH, nestin expression and ERK1/2 phosphorylation were increased in the rat CB following intraperitoneal injection of IL-1β. Moreover, IL-1β had additive effects on IHH. These results suggested that the plasticity of CB was increased following treatment with IL-1β and that ERK1/2 may be involved in neurogenic signaling in CBs. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Sympathetic regulation of vascular tone via noradrenaline and serotonin in the rat carotid body as revealed by intracellular calcium imaging.

    PubMed

    Yokoyama, Takuya; Nakamuta, Nobuaki; Kusakabe, Tatsumi; Yamamoto, Yoshio

    2015-01-30

    Hypoxia-induced chemosensory activity in the carotid body (CB) may be enhanced by the sympathetic regulation of vascular tone in the CB. In the present study, we recorded cervical sympathetic nerve activity in rats exposed to hypoxia, and examined noradrenaline (NA)- and serotonin (5-HT)-induced intracellular Ca(2+) ([Ca(2+)]i) responses in smooth muscle cells and pericytes in isolated blood vessels from the CB. Multifiber electrical activity recorded from the cervical sympathetic trunk was increased during the inhalation of hypoxic gas. NA induced [Ca(2+)]i increases in smooth muscle cells in arteriole specimens, whereas 5-HT did not cause any [Ca(2+)]i responses. However, NA did not induce [Ca(2+)]i increases in pericytes in capillaries, whereas 5-HT did and this response was inhibited by the 5-HT2 receptor antagonist, ketanserin. In conclusion, cervical sympathetic nerves enhanced by hypoxia may reduce blood flow in the CB in order to increase chemosensitivity. Thus, hypoxic chemosensitivity in the CB may involve a positive feedback mechanism via sympathetic nerves. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Serotonin-mediated modulation of hypoxia-induced intracellular calcium responses in glomus cells isolated from rat carotid body.

    PubMed

    Yokoyama, Takuya; Nakamuta, Nobuaki; Kusakabe, Tatsumi; Yamamoto, Yoshio

    2015-06-15

    In the present study, we examined serotonin (5-HT)-induced intracellular Ca(2+) ([Ca(2+)]i) responses to hypoxia in glomus cells isolated from carotid body (CB) of the rat. 5-HT did not induce any [Ca(2+)]i responses in clustered glomus cells during normoxia (21% O2), whereas, the perfusion of hypoxic solution (1% O2) induced repetitive increases in [Ca(2+)]i in the same specimens. The frequency and magnitude of hypoxia-induced [Ca(2+)]i changes observed in the glomus cells were enhanced in the presence of 5-HT, and this response was inhibited by the 5-HT2 receptor antagonist, ketanserin. Furthermore, RT-PCR analysis detected the expression of 5-HT1A, 5-HT1B, 5-HT1D, 5-HT1F, 5-HT2A, 5-HT2B, 5-HT3A, and 5-HT3B receptor mRNAs in extracts of the CB. These results suggest that 5-HT increases hypoxia-induced [Ca(2+)]i responses in glomus cells. 5-HT may elevate hypoxic responses in glomus cells in order to increase chemosensory activity of the CB.

  16. Effect of peritoneal lavage solution temperature on body temperature in anaesthetised cats and small dogs.

    PubMed

    Barnes, D C; Leece, E A; Trimble, T A; Demetriou, J L

    2017-05-20

    A prospective, randomised, non-blinded, clinical study to assess the effect of peritoneal lavage using warmed fluid on body temperature in anesthetised cats and dogs of less than 10 kg body mass undergoing coeliotomy. A standardised anaesthetic protocol was used. Oesophageal and rectal temperatures were measured at various time points. At the end of surgery, group 1 patients (n=10) were lavaged with 200 ml/kg sterile isotonic saline at 34±1°C and group 2 (n=10) at 40±1°C. Groups were similar with respect to age, mass, body condition and surgical incision length. Duration of anaesthesia, surgical procedures and peritoneal lavage was similar between groups. Linear regression showed no significant change in oesophageal temperature during the lavage period for group 1 (P=0.64), but a significant increase for group 2 patients (P<0.0001), with mean temperature changes of -0.5°C (from (36.3°C to 35.9°C) and +0.9°C (from 35.4°C to 36.3°C), respectively. Similar results were found for rectal temperature, with mean changes of -0.5°C and +0.8°C (P=0.922 and 0.045), respectively. The use of isotonic crystalloid solution for peritoneal lavage at a temperature of 40±1°C significantly warms small animal patients, when applied in a clinical setting, compared with lavage solution at 34±1°C. British Veterinary Association.

  17. Whole-Body Counter Evaluation of Internal Radioactive Cesium in Dogs and Cats Exposed to the Fukushima Nuclear Disaster

    PubMed Central

    Wada, Seiichi; Ito, Nobuhiko; Watanabe, Masamichi; Kakizaki, Takehiko; Natsuhori, Masahiro; Kawamata, Jun; Urayama, Yoshio

    2017-01-01

    As a result of the 2011 nuclear incident that occurred at the Fukushima Nuclear Power Plant, a large number of abandoned dogs and cats were left within the disaster zone. A small number of these animals were rescued and cared for at shelters. Prior to the dispersal of these animals to their owners or fosterers, we evaluated the degree of internal radiocesium contamination using a specially designed whole-body counter. We conducted 863 non-invasive measurements of gamma rays due to internal radioactive cesium for 68 dogs and 120 cats at one shelter. After plotting graphs of 137Cs density we generated exponential functions of decay from seven dogs and six cats. From the regression formulae, we were able to determine the biological half-lives as 38.2 days for dogs and 30.8 days for cats. We found that in dogs there was a correlation between the biological half-life of radioactive cesium and age. Using our data, we estimated whole-body densities for each cat and dog at the time when they were rescued. We found that there were deviations in the data distributions among the different species, likely due to the timing of rescue, or living habits prior to rescue. A significant correlation was found when extracted feline reproductive organs were analyzed; the coefficients for the estimation of whole-body densities were approximately 7-fold higher than those based on the extracted feline reproductive organs. This may be due to the fact that majority of the radioactive cesium accumulates within muscular tissue with less distribution in other organs. It is possible to plan the appropriate management period in an animal shelter based on the use of the biological half-life of radioactive cesium calculated in this study. We believe that the correlations we uncovered in this work would be of great use for the management of companion animals in the event of a future nuclear accident. PMID:28099476

  18. Whole-Body Counter Evaluation of Internal Radioactive Cesium in Dogs and Cats Exposed to the Fukushima Nuclear Disaster.

    PubMed

    Wada, Seiichi; Ito, Nobuhiko; Watanabe, Masamichi; Kakizaki, Takehiko; Natsuhori, Masahiro; Kawamata, Jun; Urayama, Yoshio

    2017-01-01

    As a result of the 2011 nuclear incident that occurred at the Fukushima Nuclear Power Plant, a large number of abandoned dogs and cats were left within the disaster zone. A small number of these animals were rescued and cared for at shelters. Prior to the dispersal of these animals to their owners or fosterers, we evaluated the degree of internal radiocesium contamination using a specially designed whole-body counter. We conducted 863 non-invasive measurements of gamma rays due to internal radioactive cesium for 68 dogs and 120 cats at one shelter. After plotting graphs of 137Cs density we generated exponential functions of decay from seven dogs and six cats. From the regression formulae, we were able to determine the biological half-lives as 38.2 days for dogs and 30.8 days for cats. We found that in dogs there was a correlation between the biological half-life of radioactive cesium and age. Using our data, we estimated whole-body densities for each cat and dog at the time when they were rescued. We found that there were deviations in the data distributions among the different species, likely due to the timing of rescue, or living habits prior to rescue. A significant correlation was found when extracted feline reproductive organs were analyzed; the coefficients for the estimation of whole-body densities were approximately 7-fold higher than those based on the extracted feline reproductive organs. This may be due to the fact that majority of the radioactive cesium accumulates within muscular tissue with less distribution in other organs. It is possible to plan the appropriate management period in an animal shelter based on the use of the biological half-life of radioactive cesium calculated in this study. We believe that the correlations we uncovered in this work would be of great use for the management of companion animals in the event of a future nuclear accident.

  19. Neural coding of repetitive clicks in the medial geniculate body of cat.

    PubMed

    Rouiller, E; de Ribaupierre, Y; Toros-Morel, A; de Ribaupierre, F

    1981-09-01

    The activity of 418 medial geniculate body (MGB) units was studied in response to repetitive acoustic pulses in 35 nitrous oxide anaesthetized cats. The proportion of MGB neurons insensitive to repetitive clicks was close to 30%. On the basis of their pattern of discharge, the responsive units were divided into three categories. The majority of them (71%), classified as "lockers', showed discharges precisely time-locked to the individual clicks of the train. A few units (8%), called "groupers', had discharges loosely synchronized to low-rate repetitive clicks. When the spikes were not synchronized, the cell had transient or sustained responses for a limited frequency range and was classified as a "special responder' (21%). Responses of "lockers' were time-locked up to a limiting rate, which varied between 10 and 800 Hz; half of the "lockers' had a limiting rate of locking equal to or higher than 100 Hz. The degree of entrainment, defined as the probability that each click evokes at least one spike, regularly decreases for increasing rates; on the other hand, the precision of locking increasing increases with frequency. The time jitter observed at 100 Hz might be as small as 0.2 ms and was 1.2 ms on average. The population of "lockers' can mark with precision the transients of complex sounds and has response properties still compatible with a temporal coding of the fundamental frequency of most animal vocalizations.

  20. Current and adolescent body fatness and fat distribution: relationships with carotid intima-media thickness and large artery stiffness at the age of 36 years.

    PubMed

    Ferreira, Isabel; Twisk, Jos W R; van Mechelen, Willem; Kemper, Han C G; Seidell, Jacob C; Stehouwer, Coen D A

    2004-01-01

    Body fat and its distribution are determinants of cardiovascular disease but the underlying mechanisms of these adverse effects are poorly understood. We therefore investigated (1) the cross-sectional relationship between estimates of body fatness and its distribution on the one hand and carotid atherosclerosis and stiffness of the carotid, femoral and brachial arteries and the carotido-femoral segment on the other (336 subjects, 175 women); (2) the relationship between estimates of body fatness and its distribution during adolescence (13-16 years) and the same arterial properties at age 36- prospective analyses (subpopulation of 159 subjects, 84 girls). Cross-sectional and prospective analyses within an ongoing observational longitudinal study: The Amsterdam Growth and Health Longitudinal Study. Body fatness and its distribution were assessed by anthropometry and dual-energy X-ray absorptiometry (DXA); arterial properties were assessed non-invasively by ultrasound imaging. Total adiposity and, in men, truncal subcutaneous fat accumulation during adolescence, were positively and independently associated with carotid intima-media thickness at age 36, a pre-clinical indicator of atherosclerosis. Adolescent truncal subcutaneous fat accumulation but not total adiposity was associated with increased arterial stiffness at age 36. At age 36, both abdominal and truncal subcutaneous fat were independently associated with arterial stiffness, while the associations between total adiposity and arterial stiffness appeared to be mediated by other cardiovascular risk factors. Body fatness and body fat distribution are associated with large artery structural and functional properties at age 36 and the roots of these associations may already be present in adolescence.

  1. Nutrition for aging cats and dogs and the importance of body condition.

    PubMed

    Laflamme, Dorothy P

    2005-05-01

    Before recommending a diet for a senior pet, a thorough nutritional evaluation should be completed. Although many middle-aged and older pets are overweight, a large percentage of geriatric cats and dogs have a low BCS. Approximately one third of cats older than 12 years of age may have a decreased ability to digest fat, whereas one in five may have a compromised ability to digest protein. Thus, appropriate diets for these two age groups may differ considerably. Mature (middle-aged) cats would likely benefit from a lower calorie food, whereas geriatric cats (>12 years of age) may need a highly digestible nutrient-dense diet. More than 40% of dogs between the ages of 5 and 10 years are overweight or obese. Such dogs may benefit from diets with lower fat and calories. Senior dogs also have an increased need for dietary protein, however. Therefore, healthy older dogs may benefit from diets with an increased protein-to-calorie ratio, providing a minimum of 25% of calories from protein. Common obesity-related conditions in dogs or cats include DM and OA. Diabetes differs between dogs and cats. Type I diabetes, common in dogs, seems to respond to fiber-enriched diets, whereas type II diabetes, common in cats, seems to benefit from high-protein and low-carbohydrate diets. OA, an inflammatory condition that occurs in approximately 20% of dogs, may benefit from weight management and nutrients that reduce the inflammatory responses, such as long-chain n-3 fatty acids.

  2. RT-PCR and pharmacological analysis of L-and T-type calcium channels in rat carotid body.

    PubMed

    Cáceres, A I; Gonzalez-Obeso, E; Gonzalez, C; Rocher, A

    2009-01-01

    Mechanisms involved in carotid body (CB) chemoreceptor cells O(2)-sensing and responses are not fully understood. So far, it is known that hypoxia depolarizes chemoreceptor cells via O(2)-sensitive K(+)-channel inhibition; calcium influx via voltage-gated channels and neurotransmitter secretion follow. Presence of high voltage activated (HVA) calcium channels in rat CB chemoreceptor cells is well documented, but the presence of low voltage activated (LVH) or T-type calcium channels has not been reported to date. The fact that O(2)-sensitive PC12 cells express T-type channels and that they are inducible by chronic hypoxia (CH) lead us to hypothesize they could be present and play a role in the genesis of the hypoxic response in rat CB chemoreceptor cells. We have analyzed the expression of the three isoforms of T-type calcium channels (alpha1G, alpha1H and alpha1I) and the isoforms alpha1C and alpha1D of L-type calcium channels in rat CB by RT-PCR. We found that rat CB expresses alpha1G and alpha1C subunits. After chronic hypoxic treatment of adult rats (10 degrees O(2), 8 days), expression of alpha1G seems to be down-regulated whereas alpha1C expression is up-regulated. Functionally, it was found that the release of catecholamine induced by hypoxia and high external K({+}) from CB chemoreceptor cells was fully sensitive to L-type channel inhibition (nisoldipine, 2 microM), while specific inhibition of T-channels (mibefradil, 2 microM) inhibited exclusively hypoxia-induced release (50 degrees ). As a whole, present findings demonstrate the presence of T-type as well as L-type calcium channels in rat CB and suggest a selective participation of the T-type channels in the hypoxic activation of chemoreceptor cells.

  3. Attenuated outward potassium currents in carotid body glomus cells of heart failure rabbit: involvement of nitric oxide

    PubMed Central

    Li, Yu-Long; Sun, Shu-Yu; Overholt, Jeffery L; Prabhakar, Nanduri R; Rozanski, George J; Zucker, Irving H; Schultz, Harold D

    2004-01-01

    It has been shown that peripheral chemoreceptor sensitivity is enhanced in both clinical and experimental heart failure (HF) and that impairment of nitric oxide (NO) production contributes to this enhancement. In order to understand the cellular mechanisms associated with the alterations of chemoreceptor function and the actions of NO in the carotid body (CB), we compared the outward K+ currents (IK) of glomus cells in sham rabbits with that in HF rabbits and monitored the effects of NO on these currents. Ik was measured in glomus cells using conventional and perforated whole-cell configurations. IK was attenuated in glomus cells of HF rabbits, and their resting membrane potentials (−34.7 ± 1.0 mV) were depolarized as compared with those in sham rabbits (−47.2 ± 1.9 mV). The selective Ca2+-dependent K+ channel (KCa) blocker iberiotoxin (IbTx, 100 nm) reduced IK in glomus cells from sham rabbits, but had no effect on IK from HF rabbits. In perforated whole-cell mode, the NO donor SNAP (100 μm) increased IK in glomus cells from HF rabbits to a greater extent than that in sham rabbits (P < 0.01), and IbTx inhibited the effects of SNAP. However, in conventional whole-cell mode, SNAP had no effect. Nω-nitro-L-arginine (L-NNA, NO synthase inhibitor) decreased Ik in sham rabbits but not in HF rabbits. The guanylate cyclase inhibitor 1H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one (ODQ) inhibited the effect of SNAP on Ik. These results demonstrate that IK is reduced in CB glomus cells from HF rabbits. This effect is due mainly to the suppression of KCa channel activity caused by decreased availability of NO. In addition, intracellular cGMP is necessary for the KCa channel modulation by NO. PMID:14673183

  4. Type I cell ROS kinetics under hypoxia in the intact mouse carotid body ex vivo: a FRET-based study.

    PubMed

    Bernardini, A; Brockmeier, U; Metzen, E; Berchner-Pfannschmidt, U; Harde, E; Acker-Palmer, A; Papkovsky, D; Acker, H; Fandrey, J

    2015-01-01

    Reactive oxygen species (ROS) mainly originating from NADPH oxidases have been shown to be involved in the carotid body (CB) oxygen-sensing cascade. For measuring ROS kinetics, type I cells of the mouse CB in an ex vivo preparation were transfected with the ROS sensor construct FRET-HSP33. After 2 days of tissue culture, type I cells expressed FRET-HSP33 as shown by immunohistochemistry. In one population of CBs, 5 min of hypoxia induced a significant and reversible decrease of type I cell ROS levels (n = 9 CBs; P < 0.015), which could be inhibited by 4-(2-aminoethyl)benzensulfonylfluorid (AEBSF), a highly specific inhibitor of the NADPH oxidase subunits p47(phox) and p67(phox). In another population of CBs, however, 5 min of hypoxia induced a significant and reversible increase of ROS levels in type I cells (n = 8 CBs; P < 0.05), which was slightly enhanced by administration of 3 mM AEBSF. These different ROS kinetics seemed to coincide with different mice breeding conditions. Type I cells of both populations showed a typical hypoxia-induced membrane potential (MP) depolarization, which could be inhibited by 3 mM AEBSF. ROS and MP closely followed the hypoxic decrease in CB tissue oxygen as measured with an O2-sensitive dye. We conclude that attenuated p47(phox) subunit activity of the NADPH oxidase under hypoxia is the physiological trigger for type I cell MP depolarization probably due to ROS decrease, whereas the observed ROS increase has no influence on type I cell MP kinetics under hypoxia.

  5. Regulation of hypoxia-inducible factor-α isoforms and redox state by carotid body neural activity in rats

    PubMed Central

    Peng, Ying-Jie; Yuan, Guoxiang; Khan, Shakil; Nanduri, Jayasri; Makarenko, Vladislav V; Reddy, Vaddi Damodara; Vasavda, Chirag; Kumar, Ganesh K; Semenza, Gregg L; Prabhakar, Nanduri R

    2014-01-01

    Previous studies reported that chronic intermittent hypoxia (CIH) results in an imbalanced expression of hypoxia-inducible factor-α (HIF-α) isoforms and oxidative stress in rodents, which may be due either to the direct effect of CIH or indirectly via hitherto uncharacterized mechanism(s). As neural activity is a potent regulator of gene transcription, we hypothesized that carotid body (CB) neural activity contributes to CIH-induced HIF-α isoform expression and oxidative stress in the chemoreflex pathway. Experiments were performed on adult rats exposed to CIH for 10 days. Rats exposed to CIH exhibited: increased HIF-1α and decreased HIF-2α expression; increased NADPH oxidase 2 and decreased superoxide dismutase 2 expression; and oxidative stress in the nucleus tractus solitarius and rostral ventrolateral medulla as well as in the adrenal medulla (AM), a major end organ of the sympathetic nervous system. Selective ablation of the CB abolished these effects. In the AM, sympathetic activation by the CB chemoreflex mediates CIH-induced HIF-α isoform imbalance via muscarinic acetylcholine receptor-mediated Ca2+ influx, and the resultant activation of mammalian target of rapamycin pathway and calpain proteases. Rats exposed to CIH presented with hypertension, elevated sympathetic activity and increased circulating catecholamines. Selective ablation of either the CB (afferent pathway) or sympathetic innervation to the AM (efferent pathway) abolished these effects. These observations uncover CB neural activity-dependent regulation of HIF-α isoforms and the redox state by CIH in the central and peripheral nervous systems associated with the chemoreflex. PMID:24973414

  6. Postsynaptic action of GABA in modulating sensory transmission in co-cultures of rat carotid body via GABAA receptors

    PubMed Central

    Zhang, Min; Clarke, Katherine; Zhong, Huijun; Vollmer, Cathy; Nurse, Colin A

    2009-01-01

    GABA is expressed in carotid body (CB) chemoreceptor type I cells and has previously been reported to modulate sensory transmission via presynaptic GABAB receptors. Because low doses of clinically important GABAA receptor (GABAAR) agonists, e.g. benzodiazepines, have been reported to depress afferent CB responses to hypoxia, we investigated the potential contribution of GABAAR in co-cultures of rat type I cells and sensory petrosal neurones (PNs). During gramicidin perforated-patch recordings (to preserve intracellular Cl−), GABA and/or the GABAA agonist muscimol (50 μm) induced a bicuculline-sensitive membrane depolarization in isolated PNs. GABA-induced whole-cell currents reversed at ∼−38 mV and had an EC50 of ∼10 μm (Hill coefficient =∼1) at −60 mV. During simultaneous PN and type I cell recordings at functional chemosensory units in co-culture, bicuculline reversibly potentiated the PN, but not type I cell, depolarizing response to hypoxia. Application of the CB excitatory neurotransmitter ATP (1 μm) over the soma of functional PN induced a spike discharge that was markedly suppressed during co-application with GABA (2 μm), even though GABA alone was excitatory. RT-PCR analysis detected expression of GABAergic markers including mRNA for α1, α2, β2, γ2S, γ2L and γ3 GABAAR subunits in petrosal ganglia extracts. Also, CB extracts contained mRNAs for GABA biosynthetic markers, i.e. glutamate decarboxylase (GAD) isoforms GAD 67A,E, and GABA transporter isoforms GAT 2,3 and BGT-1. In CB sections, sensory nerve endings apposed to type I cells were immunopositive for the GABAAR β subunit. These data suggest that GABA, released from the CB during hypoxia, inhibits sensory discharge postsynaptically via a shunting mechanism involving GABAA receptors. PMID:19029183

  7. Hypoxia induces voltage-dependent Ca2+ entry and quantal dopamine secretion in carotid body glomus cells.

    PubMed Central

    Ureña, J; Fernández-Chacón, R; Benot, A R; Alvarez de Toledo, G A; López-Barneo, J

    1994-01-01

    We have investigated the changes of cytosolic [Ca2+] and the secretory activity in single glomus cells dispersed from rabbit carotid bodies during exposure to solutions with variable O2 tension (Po2). In normoxic conditions (Po2 = 145 mmHg; 1 mmHg = 133 Pa), intracellular [Ca2+] was 58 +/- 29 nM, and switching to low Po2 (between 10 and 60 mmHg) led to a reversible increase of [Ca2+] up to 800 nM. The response to hypoxia completely disappeared after removal of external Ca2+ or with the addition of 0.2 mM Cd2+ to the external solution. These same solutions also abolished both the Ca2+ current of the cells and the increase of internal [Ca2+] elicited by high external K+. Elevations of cytosolic [Ca2+] in response to hypoxia or to direct membrane depolarization elicited the release of dopamine, which was detected by amperometric techniques. Dopamine secretion occurred in episodes of spike-like activity that appear to represent the release from single secretory vesicles. From the mean charge of well-resolved secretory events, we estimated the average number of dopamine molecules per vesicle to be approximately 140,000, a value about 15 times smaller than a previous estimate in chromaffin granules of adrenomedullary cells. These results directly demonstrate in a single-cell preparation the secretory response of glomus cells to hypoxia. The data indicate that the enhancement of cellular excitability upon exposure to low Po2 results in Ca2+ entry through voltage-gated channels, which leads to an increase in intracellular [Ca2+] and exocytotic transmitter release. PMID:7937863

  8. An Unusual Case of a Nasal Foreign Body in a Cat with Chronic Nasal Discharge.

    PubMed

    Bellei, Emma; Pisoni, Luciano; Joechler, Monika; Pietra, Marco

    2015-01-01

    This report describes a cat infected with the feline infectious virus and a 1 yr history of unilateral mucopurulent nasal discharge. Intraoral radiography and endoscopic examination revealed the presence of a large fragment of tooth root in the right nasal cavity. The cat had previously undergone maxillary canine tooth (104) extraction. The root was successfully removed by an endoscopic-assisted procedure, and follow-up examination 1 yr later documented complete disappearance of the respiratory signs.

  9. Dissociation between blood pressure and heart rate response to hypoxia after bilateral carotid body removal in men with systolic heart failure.

    PubMed

    Niewinski, Piotr; Janczak, Dariusz; Rucinski, Artur; Tubek, Stanislaw; Engelman, Zoar J; Jazwiec, Przemyslaw; Banasiak, Waldemar; Sobotka, Paul A; Hart, Emma C J; Paton, Julian F R; Ponikowski, Piotr

    2014-03-01

    While the ventilatory response to hypoxia is known to be mediated by the carotid bodies, the origin of the haemodynamic alterations evoked by hypoxia is less certain. Bilateral carotid body removal (CBR) performed to treat congestive heart failure may serve as a model to improve our understanding of haemodynamic responses to hypoxia in humans. We studied six congestive heart failure patients before and 1 month after CBR [median (interquartile range): age, 58.5 (56-61) years old; and ejection fraction, 32 (25-34)%]. Peripheral chemosensitivity (hypoxic ventilatory response) was equated to the slope relating lowest oxygen saturation to highest minute ventilation following exposures to hypoxia. Likewise, systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) slopes were calculated as slopes relating the lowest oxygen saturations to the highest SBP, DBP and HR responses. We found that CBR reduces the hypoxic ventilatory response (91%, P < 0.05), SBP (71%, P < 0.05) and DBP slopes (59%, P = 0.07). In contrast, the HR slope remained unchanged. The dissociation between the blood pressure and HR responses after CBR shows involvement of a different chemoreceptive site(s) maintaining the response to acute hypoxia. We conclude that carotid bodies are responsible for ventilatory and blood pressure responses, while the HR response might be mediated by the aortic bodies. The significant reduction of the blood pressure response to hypoxia after CBR suggests a decrease in sympathetic tone, which is of particular clinical relevance in congestive heart failure.

  10. Inverse relationship between the body mass index and severity of carotid siphon calcifications (another obesity paradox): Results from the Atahualpa Project.

    PubMed

    Del Brutto, Oscar H; Mera, Robertino M

    2017-04-01

    The importance of the obesity paradox in the intracranial vasculature has not been explored. We assessed whether the body mass index (BMI) correlates with severity of carotid siphon calcifications (CSC) in community-dwelling adults. Using a population-based study design, Atahualpa residents aged ≥40 years underwent head computed tomography (CT) for assessment of CSC. We evaluated the association between BMI and severity of CSC (dependent variable) using regression models adjusted for demographics and cardiovascular risk factors. Of 830 people enrolled in the Atahualpa Project, 651 (78%) were included. Mean BMI was 27.3 ± 5 kg/m(2), with 39% being overweight and 27% obese. CT revealed high calcium content in the carotid siphon in 25% participants. In an adjusted model, individuals with normal weight had a trend for presenting with more severe CSC than those overweight (p = 0.06), and those ones had significantly more severe CSC than obese participants (p = 0.04). Predictive margins of BMI were higher in individuals with low calcium content in the carotid siphon. A contour plot with Shepard interpolation showed that the paradox disappeared in older individuals and in those with severe obesity, irrespective of age. BMI inversely associates with severity of CSC. This paradox is relevant in younger individuals and in those without severe obesity, irrespective of age. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Haloperidol-induced suppression of carotid chemoreception in vitro.

    PubMed

    Nolan, W F; Donnelly, D F; Smith, E J; Dutton, R E

    1985-09-01

    Effects of antagonism of endogenous dopamine with haloperidol on single-unit frequency, interspike interval distribution, and interval serial dependency of the cat sinus nerve were tested using an in vitro carotid body-sinus nerve superfusion technique. A dose dependency of inhibition by haloperidol (0.05-2.0 microgram/ml) was observed. Superfusion with 1-2 microgram/ml haloperidol significantly reduced frequency within 5 min (P less than 0.05) and caused a complete cessation of firing within 25 min in 5 of 10 chemoreceptor units. Frequency recovered to control during drug washout. Acetylcholine (10-micrograms/ml superfusion or 500-micrograms bolus) increased sinus nerve activity under control conditions but not during superfusion with haloperidol. No effect of haloperidol on impulse serial dependency was detected. However, interval distribution was significantly altered by haloperidol in five of six chemoreceptor units. Our results suggest an excitatory role for dopamine in carotid chemoreception.

  12. Neurons sensitive to narrow ranges of repetitive acoustic transients in the medial geniculate body of the cat.

    PubMed

    Rouiller, E; de Ribaupierre, F

    1982-01-01

    Neuronal activity was recorded in the medial geniculate body (MGB) of nitrous oxide anaesthetized, paralysed cats in response to click trains. For most cells responding to these stimuli the spike discharges are precisely time locked to individual clicks within the train. The present study has revealed that, apart from the normal "locker" response being characterized by a monotonic decrease in the entrainment as the frequency of the clicks within the train increases, there is a small population of "lockers" which show a non-monotonic response to increasing click frequency. 41% of these non-monotonic cells were not at all entrained by the lowest click rates and had time-locked responses for very restricted frequency ranges. These particular non-monotonic "lockers" were more commonly-found in the posterior part of the pars lateralis and in the suprageniculate nucleus. These cells might be involved in the temporal coding of natural sounds such as animal vocalizations and the cat's purr.

  13. A revisit to O2 sensing and transduction in the carotid body chemoreceptors in the context of reactive oxygen species biology.

    PubMed

    Gonzalez, C; Agapito, M T; Rocher, A; Gomez-Niño, A; Rigual, R; Castañeda, J; Conde, S V; Obeso, A

    2010-12-31

    Oxygen-sensing and transduction in purposeful responses in cells and organisms is of great physiological and medical interest. All animals, including humans, encounter in their lifespan many situations in which oxygen availability might be insufficient, whether acutely or chronically, physiologically or pathologically. Therefore to trace at the molecular level the sequence of events or steps connecting the oxygen deficit with the cell responses is of interest in itself as an achievement of science. In addition, it is also of great medical interest as such knowledge might facilitate the therapeutical approach to patients and to design strategies to minimize hypoxic damage. In our article we define the concepts of sensors and transducers, the steps of the hypoxic transduction cascade in the carotid body chemoreceptor cells and also discuss current models of oxygen- sensing (bioenergetic, biosynthetic and conformational) with their supportive and unsupportive data from updated literature. We envision oxygen-sensing in carotid body chemoreceptor cells as a process initiated at the level of plasma membrane and performed by a hemoprotein, which might be NOX4 or a hemoprotein not yet chemically identified. Upon oxygen-desaturation, the sensor would experience conformational changes allosterically transmitted to oxygen regulated K+ channels, the initial effectors in the transduction cascade. A decrease in their opening probability would produce cell depolarization, activation of voltage dependent calcium channels and release of neurotransmitters. Neurotransmitters would activate the nerve endings of the carotid body sensory nerve to convey the information of the hypoxic situation to the central nervous system that would command ventilation to fight hypoxia.

  14. The role of sodium and calcium ions in the hypothalamus in the control of body temperature of the unanaesthetized cat

    PubMed Central

    Myers, R. D.; Veale, W. L.

    1971-01-01

    1. Isolated regions of the anterior, posterior and other areas of the hypothalamus of the unanaesthetized cat were perfused by means of push-pull cannulae lowered through permanently implanted guide tubes. Each site was perfused for a 30 min interval at a rate of 50 μl./min. Concentrations of sodium, calcium, potassium and magnesium ions in the perfusate were altered selectively. 2. Sodium ions in a concentration which varied from 13·6 to 68·0 mM in excess of the level in extracellular fluid caused a steep rise in the temperature of the cat when the solution was perfused at sites located within the posterior hypothalamic area. Shivering, vasoconstriction, and piloerection accompanied the increase in temperature. When the chloride was replaced in the perfusate by the toluene-p-sulphonate salt of sodium, the hyperthermia was equally intense. Solutions containing excess sodium ions perfused within the anterior and other hypothalamic areas produced either a slight fall or rise in temperature as well as other physiological changes. 3. Calcium ions in a concentration which varied from 2·6 to 10·4 mM in excess of the physiological level perfused at the same sites within the posterior region of the hypothalamus produced a sharp fall in body temperature, which was accompanied by vasodilatation and a decrease in the activity of the cat. When solutions containing excess calcium were perfused in the anterior and other hypothalamic areas, no consistent change in temperature occurred. 4. Potassium or magnesium ions in concentrations which varied from two to ten times the level in extracellular fluid had virtually no effect on the temperature of the cat when they were perfused in the anterior, posterior or other areas of the hypothalamus. 5. We conclude that the constancy in the ratio between sodium and calcium ions in the posterior hypothalamus may be the inherent mechanism by which the set-point for body temperature is determined. ImagesFig. 7 PMID:5548019

  15. Bilateral Carotid Artery Injury Response in Side Impact Using a Vessel Model Integrated with a Human Body Model

    PubMed Central

    Danelson, Kerry A.; Gayzik, F. Scott; Yu, Mao M.; Martin, R. Shayn; Duma, Stefan M.; Stitzel, Joel D.

    2009-01-01

    In a far-side crash configuration, the occupant can experience severe excursion from the seat space. Given this challenge, there are research efforts focused on alternate restraints, such as four-point belts. A potential implication of this geometry would be interaction of the belt with the occupant’s neck. This study examines the response of the carotid arteries using a Finite Element Model (FEM) in a far-side crash configuration with a reversed three-point restraint. A FEM of the carotid artery and neck fascia was developed and integrated with the Total Human Model for Safety (THUMS) version 1.44. This model was subjected to four test conditions simulating far-side crashes. Load conditions included a low velocity impact of approximately 4 m/s and a higher velocity impact of approximately 10 m/s. For each velocity, the model was restrained with a belt placed low on the neck and a belt placed higher on the neck. Strain data in each element of the carotid arteries was analyzed. The overall response of the vessel was examined to determine locations of high strain values. Low belt placement resulted in more head excursion, stretching the carotid on the non-struck side. High belt placement resulted in compression of the artery on the struck side due to direct loading of the vessel from the belt. Strain values in the carotid artery elements increased with increasing speed of impact. The lower and higher speed tests with a low belt configuration resulted in a maximum principal strains, at maximal belt engagement, of 0.223 and 0.459, respectively. Corresponding values for the high belt configuration were 0.222 and 0.563. In both belt configurations, the non-struck side vessel stretched more than the struck side vessel; however, the non-struck side vessel experienced higher compressive forces. Strain values measured during the simulations can be compared to a value of 0.31 to intimal failure in previous experimental tests. These results quantitatively illustrate the two

  16. CaV3.2 T-type Ca2+ channels mediate the augmented calcium influx in carotid body glomus cells by chronic intermittent hypoxia

    PubMed Central

    Makarenko, Vladislav V.; Ahmmed, Gias U.; Peng, Ying-Jie; Khan, Shakil A.; Nanduri, Jayasri; Kumar, Ganesh K.; Fox, Aaron P.

    2015-01-01

    Chronic intermittent hypoxia (CIH) is a hallmark manifestation of sleep apnea. A heightened carotid body activity and the resulting chemosensory reflex mediate increased sympathetic nerve activity by CIH. However, the mechanisms underlying heightened carotid body activity by CIH are not known. An elevation of intracellular calcium ion concentration ([Ca2+]i) in glomus cells, the primary oxygen-sensing cells, is an essential step for carotid body activation by hypoxia. In the present study, we examined the effects of CIH on the glomus cell [Ca2+]i response to hypoxia and assessed the underlying mechanisms. Glomus cells were harvested from adult rats or wild-type mice treated with 10 days of either room air (control) or CIH (alternating cycles of 15 s of hypoxia and 5 min of room air; 9 episodes/h; 8 h/day). CIH-treated glomus cells exhibited an enhanced [Ca2+]i response to hypoxia, and this effect was absent in the presence of 2-(4-cyclopropylphenyl)-N-((1R)-1-[5-[(2,2,2-trifluoroethyl)oxo]-pyridin-2-yl]ethyl)acetamide (TTA-A2), a specific inhibitor of T-type Ca2+ channels, and in voltage-gated calcium channel, type 3.2 (CaV3.2), null glomus cells. CaV3.2 knockout mice exhibited an absence of CIH-induced hypersensitivity of the carotid body. CIH increased reactive oxygen species (ROS) levels in glomus cells. A ROS scavenger prevented the exaggerated TTA-A2-sensitive [Ca2+]i response to hypoxia. CIH had no effect on CaV3.2 mRNA levels. CIH augmented Ca2+ currents and increased CaV3.2 protein in plasma membrane fractions of human embryonic kidney-293 cells stably expressing CaV3.2, and either a ROS scavenger or brefeldin-A, an inhibitor of protein trafficking, prevented these effects. These findings suggest that CIH leads to an augmented Ca2+ influx via ROS-dependent facilitation of CaV3.2 protein trafficking to the plasma membrane. PMID:26561606

  17. CaV3.2 T-type Ca2+ channels mediate the augmented calcium influx in carotid body glomus cells by chronic intermittent hypoxia.

    PubMed

    Makarenko, Vladislav V; Ahmmed, Gias U; Peng, Ying-Jie; Khan, Shakil A; Nanduri, Jayasri; Kumar, Ganesh K; Fox, Aaron P; Prabhakar, Nanduri R

    2016-01-01

    Chronic intermittent hypoxia (CIH) is a hallmark manifestation of sleep apnea. A heightened carotid body activity and the resulting chemosensory reflex mediate increased sympathetic nerve activity by CIH. However, the mechanisms underlying heightened carotid body activity by CIH are not known. An elevation of intracellular calcium ion concentration ([Ca(2+)]i) in glomus cells, the primary oxygen-sensing cells, is an essential step for carotid body activation by hypoxia. In the present study, we examined the effects of CIH on the glomus cell [Ca(2+)]i response to hypoxia and assessed the underlying mechanisms. Glomus cells were harvested from adult rats or wild-type mice treated with 10 days of either room air (control) or CIH (alternating cycles of 15 s of hypoxia and 5 min of room air; 9 episodes/h; 8 h/day). CIH-treated glomus cells exhibited an enhanced [Ca(2+)]i response to hypoxia, and this effect was absent in the presence of 2-(4-cyclopropylphenyl)-N-((1R)-1-[5-[(2,2,2-trifluoroethyl)oxo]-pyridin-2-yl]ethyl)acetamide (TTA-A2), a specific inhibitor of T-type Ca(2+) channels, and in voltage-gated calcium channel, type 3.2 (CaV3.2), null glomus cells. CaV3.2 knockout mice exhibited an absence of CIH-induced hypersensitivity of the carotid body. CIH increased reactive oxygen species (ROS) levels in glomus cells. A ROS scavenger prevented the exaggerated TTA-A2-sensitive [Ca(2+)]i response to hypoxia. CIH had no effect on CaV3.2 mRNA levels. CIH augmented Ca(2+) currents and increased CaV3.2 protein in plasma membrane fractions of human embryonic kidney-293 cells stably expressing CaV3.2, and either a ROS scavenger or brefeldin-A, an inhibitor of protein trafficking, prevented these effects. These findings suggest that CIH leads to an augmented Ca(2+) influx via ROS-dependent facilitation of CaV3.2 protein trafficking to the plasma membrane. Copyright © 2016 the American Physiological Society.

  18. Age and body weight effects on glucose and insulin tolerance in colony cats maintained since weaning on high dietary carbohydrate.

    PubMed

    Backus, R C; Cave, N J; Ganjam, V K; Turner, J B M; Biourge, V C

    2010-12-01

    High dietary carbohydrate is suggested to promote development of diabetes mellitus in cats. Glucose tolerance, insulin sensitivity, and insulin secretion were assessed in young [0.8-2.3 (median = 1.1) years, n = 13] and mature [4.0-7.0 (median 5.8) years, n = 12] sexually intact females of a large (n ≅ 700) feline colony in which only dry-type diets (35% metabolizable energy as carbohydrate) were fed from weaning. Insulin sensitivity was assessed from the 'late-phase' (60-120 min) plasma insulin response of intravenous glucose tolerance tests (IVGTTs) and from fractional change in glycaemia from baseline 15 min after an insulin bolus (0.1 U/kg, i.v.). Insulin secretion was assessed from the 'early-phase' (0-15 min) plasma insulin response of IVGTTs. Compared to the young cats, the mature cats had greater body weights [2.3-3.8 (median = 2.9) vs. 3.0-6.3 (median = 4.0) kg, p < 0.01], greater late-phase insulin responses (p < 0.05), lower insulin-induced glycaemic changes (p = 0.06), lower early-phase insulin responses (p < 0.05), and non-significantly different rates of glucose disposal. The late-phase insulin response was correlated with body weight and age (p < 0.05). When group assignments were balanced for body weight, the age-group differences and correlations became non-significant. The findings indicate that body weight gain is more likely than dry-type diets to induce the pre-diabetic conditions of insulin resistance and secretion dysfunction.

  19. Relative mitochondrial membrane potential and [Ca2+]i in type I cells isolated from the rabbit carotid body.

    PubMed Central

    Duchen, M R; Biscoe, T J

    1992-01-01

    1. In the accompanying paper (Duchen & Biscoe, 1992) we have described graded changes in autofluorescence derived from mitochondrial NAD(P)H in type I cells of the carotid body in response to changes of PO2 over a physiologically significant range. These observations suggest that mitochondrial function in these cells is unusually sensitive to oxygen and could play a role in oxygen sensing. We have now explored further the relationships between hypoxia, mitochondrial membrane potential (delta psi m) and [Ca2+]i. 2. The fluorescence of Rhodamine 123 (Rh 123) accumulated within mitochondria is quenched by delta psi m. Mitochondrial depolarization thus increases the fluorescence signal. Blockade of electron transport (CN-, anoxia, rotenone) and uncoupling agents (e.g. carbonyl cyanide p-trifluoromethoxy-phenylhydrazone; FCCP) increased fluorescence by up to 80-120%, while fluorescence was reduced by blockade of the F0 proton channel of the mitochondrial ATP synthase complex (oligomycin). 3. delta psi m depolarized rapidly with anoxia, and was usually completely dissipated within 1-2 min. The depolarization of delta psi m with anoxia (or CN-) and repolarization on reoxygenation both followed a time course well characterized as the sum of two exponential processes. Oligomycin (0.2-2 micrograms/ml) hyperpolarized delta psi m and abolished the slower components of both the depolarization with anoxia and of the subsequent repolarization. These data (i) illustrate the role of the F1-F0 ATP synthetase in slowing the rate of dissipation of delta psi m on cessation of electron transport, (ii) confirm blockade of the ATP synthetase by oligomycin at these concentrations, and (iii) indicate significant accumulation of intramitochondrial ADP during 1-2 min of anoxia. 4. Depolarization of delta psi m was graded with graded changes in PO2 below about 60 mmHg. The stimulus-response curves thus constructed strongly resemble those for [Ca2+]i and NAD(P)H with PO2. The change in delta

  20. The effect of reducing dietary energy density via the addition of water to a dry diet, on body weight, energy intake and physical activity in adult neutered cats.

    PubMed

    Alexander, Janet E; Colyer, Alison; Morris, Penelope J

    2014-01-01

    Increasingly domestic cats live in an overfeeding and underexercising environment where obesity is a major health concern. One strategy to aid healthy body weight maintenance is dietary energy dilution. Published data indicate that increasing dietary moisture content leads to a reduction in energy intake and increased activity. However, a number of different methodologies were employed in these studies and associated changes in physical activity have only been measured once. The aim of the present study was to determine the effect of diets of three different moisture contents offered in excess of energy requirements, on body weight, energy intake and physical activity in adult neutered cats. Sixty-nine adult cats randomised into three groups, received 100 % of their daily individual maintenance energy requirements (IMER) of dry diet or dry diet hydrated to 40 or 80 % total moisture content (tmc). Baseline activity, intake, body weight and body composition were measured. Following this baseline phase, the cats received the same diets at 200 % of daily IMER and the measurements repeated over the next 28 d. When offered the diets at 200 % IMER, cats fed the dry diet significantly increased body weight and percentage of body fat (P < 0·01), while those offered the hydrated diets did not (P > 0·01). The levels of physical activity in cats offered the hydrated 80 % tmc diet were significantly (P < 0·01) higher than those offered the dry or 40 % tmc diet. We suggest that dietary energy dilution by addition of water may be a useful strategy for healthy body weight maintenance in overfed cats.

  1. Whole-body biodistribution of 3'-deoxy-3'-[(18) f]fluorothymidine ((18) FLT) in healthy adult cats.

    PubMed

    Rowe, Joshua A; Morandi, Federica; Wall, Jonathan S; Akula, Murthy; Kennel, Stephen J; Osborne, Dustin; Martin, Emily B; Galyon, Gina D; Long, Misty J; Stuckey, Alan C; LeBlanc, Amy K

    2013-01-01

    Positron emission tomography/computed tomography (PET/CT) utilizing 3'-deoxy-3'-[(18) F]fluorothymidine ((18) FLT), a proliferation tracer, has been found to be a useful tool for characterizing neoplastic diseases and bone marrow function in humans. As PET and PET/CT imaging become increasingly available in veterinary medicine, knowledge of radiopharmaceutical biodistribution in veterinary species is needed for lesion interpretation in the clinical setting. The purpose of this study was to describe the normal biodistribution of (18) FLT in adult domestic cats. Imaging of six healthy young adult castrated male cats was performed using a commercially available PET/CT scanner consisting of a 64-slice helical CT scanner with an integrated whole-body, high-resolution lutetium oxy-orthosilicate (LSO) PET scanner. Cats were sedated and injected intravenously with 108.60 ± 2.09 (mean ± SD) MBq of (18) FLT (greater than 99% radiochemical purity by high-performance liquid chromatography). Imaging was performed in sternal recumbency under general anesthesia. Static images utilizing multiple bed positions were acquired 80.83 ± 7.52 (mean ± SD) minutes post-injection. Regions of interest were manually drawn over major parenchymal organs and selected areas of bone marrow and increased tracer uptake. Standardized uptake values were calculated. Notable areas of uptake included hematopoietic bone marrow, intestinal tract, and the urinary and hepatobiliary systems. No appreciable uptake was observed within brain, lung, myocardium, spleen, or skeletal muscle. Findings from this study can be used as baseline data for future studies of diseases in cats.

  2. Effects of modulators of AMP-activated protein kinase on TASK-1/3 and intracellular Ca2+ concentration in rat carotid body glomus cells

    PubMed Central

    Kim, Donghee; Kang1,2, Dawon; Martin, Elizabeth A.; Kim, Insook; Carroll, John L.

    2014-01-01

    Acute hypoxia depolarizes carotid body chemoreceptor (glomus) cells and elevates intracellular Ca2+ concentration ([Ca2+]i). Recent studies suggest that AMP-activated protein kinase (AMPK) mediates these effects of hypoxia by inhibiting the background K+ channels such as TASK. Here we studied the effects of modulators of AMPK on TASK activity in cell-attached patches. Activators of AMPK (1 mM AICAR and 0.1–0.5 mM A769662) did not inhibit TASK activity or cause depolarization during acute (10 min) or prolonged (2–3 hr) exposure. Hypoxia inhibited TASK activity by ~70% in cells pretreated with AICAR or A769662. Both AICAR and A769662 (15–40 min) failed to increase [Ca2+]i in glomus cells. Compound C (40 µM), an inhibitor of AMPK, showed no effect on hypoxia-induced inhibition of TASK. AICAR and A769662 phosphorylated AMPKα in PC12 cells, and Compound C blocked the phosphorylation. Our results suggest that AMPK does not affect TASK activity and is not involved in hypoxia-induced elevation of intracellular [Ca2+] in isolated rat carotid body glomus cells. PMID:24530802

  3. Carotid duplex

    MedlinePlus

    ... moved around your neck. The pressure should not cause any pain. You may also hear a "whooshing" sound. This is normal. ... clotting (thrombosis) Narrowing in the arteries (stenosis) Other ... an abnormal sound called a bruit over the carotid neck arteries. ...

  4. Carotid Endarterectomy

    MedlinePlus

    ... is not a cure. Your arteries can become blocked again if your underlying condition, such as high ... or cut, on your neck to expose the blocked section of the carotid artery. Your surgeon will ...

  5. Association between adjunctive metformin therapy in young type 1 diabetes patients with excess body fat and reduction of carotid intima-media thickness.

    PubMed

    Burchardt, Paweł; Zawada, Agnieszka; Kaczmarek, Jolanta; Marcinkaniec, Justyna; Wysocki, Henryk; Wierusz-Wysocka, Bogna; Grzymisławski, Marian; Rzeźniczak, Janusz; Zozulińska-Ziółkiewicz, Dorota; Naskręt, Dariusz

    2016-08-25

    INTRODUCTION    Lipoprotein-associated phospholipase A2 (Lp-PLA2) and cholesteryl ester lipase (CEL) may oxidize low-density lipoproteins (oxLDL). OBJECTIVES    The aim of the study was to determine the influence of metformin on the metabolism of atherogenic lipid fractions in relation to Lp-PLA2 and CEL levels, as well as assess consequent improvement in the intima-media thickness (IMT) of the common carotid artery in young type 1 diabetes patients with excess body fat. PATIENTS AND METHODS    It was an open-label randomized clinical trial that lasted 6 months. It included a total of 84 people with metabolic decompensation (glycated hemoglobin >7.5%, >58.5 mmol/mol) of diabetes. Adjunctive metformin therapy (in addition to insulin) was administered in 42 patients, and the remaining 42 patients received insulin alone. Glycated low-density lipoproteins (LDLs), oxLDL, Lp-PLA2, and CEL were assessed by commercially available enzyme-linked immunosorbent assay kits. Cartoid IMT was measured using the Carotid Analyser for Research tool. Biochemical analyses were performed using routine laboratory techniques. RESULTS    The reduction of mean carotid IMT was observed in young type 1 diabetic adults treated additionally with metformin (0.6 ±0.1 cm vs 0.53 ±0.1 cm; P = 0.002). This effect was probably due to weight reduction (90 ±16 kg vs 87 ±15 kg, P = 0.054) and the decrease in atherogenic glycated LDL levels (1.5 ±0.5 mg/dl vs 1.6 ±1.046 mg/dl, P = 0.006). No such correlations were observed in patients treated with insulin alone. Additionally, in patients receiving metformin, glycated LDL levels were inversely correlated with Lp-PLA2 levels (r = -0.31, P <0.05). CONCLUSIONS    Additional use of metformin in young type 1 diabetic patients with excess body fat leads to a significant reduction of mean IMT in the common carotid artery. Concentrations of CEL and Lp-PLA2 were significantly increased in both study arms despite improved glucose metabolism.

  6. Carotid Artery Screening

    MedlinePlus

    ... Physician Resources Professions Site Index A-Z Carotid Artery Screening What is carotid artery screening? Who should ... information about carotid artery screening? What is carotid artery screening? Screening examinations are tests performed to find ...

  7. Responses of neurons in the rostral ventrolateral medulla to whole body rotations: comparisons in decerebrate and conscious cats

    PubMed Central

    DeStefino, V. J.; Reighard, D. A.; Sugiyama, Y.; Suzuki, T.; Cotter, L. A.; Larson, M. G.; Gandhi, N. J.; Barman, S. M.

    2011-01-01

    The responses to vestibular stimulation of brain stem neurons that regulate sympathetic outflow and blood flow have been studied extensively in decerebrate preparations, but not in conscious animals. In the present study, we compared the responses of neurons in the rostral ventrolateral medulla (RVLM), a principal region of the brain stem involved in the regulation of blood pressure, to whole body rotations of conscious and decerebrate cats. In both preparations, RVLM neurons exhibited similar levels of spontaneous activity (median of ∼17 spikes/s). The firing of about half of the RVLM neurons recorded in decerebrate cats was modulated by rotations; these cells were activated by vertical tilts in a variety of directions, with response characteristics suggesting that their labyrinthine inputs originated in otolith organs. The activity of over one-third of RVLM neurons in decerebrate animals was altered by stimulation of baroreceptors; RVLM units with and without baroreceptor signals had similar responses to rotations. In contrast, only 6% of RVLM neurons studied in conscious cats exhibited cardiac-related activity, and the firing of just 1% of the cells was modulated by rotations. These data suggest that the brain stem circuitry mediating vestibulosympathetic reflexes is highly sensitive to changes in body position in space but that the responses to vestibular stimuli of neurons in the pathway are suppressed by higher brain centers in conscious animals. The findings also raise the possibility that autonomic responses to a variety of inputs, including those from the inner ear, could be gated according to behavioral context and attenuated when they are not necessary. PMID:21493724

  8. Responses of neurons in the rostral ventrolateral medulla to whole body rotations: comparisons in decerebrate and conscious cats.

    PubMed

    Destefino, V J; Reighard, D A; Sugiyama, Y; Suzuki, T; Cotter, L A; Larson, M G; Gandhi, N J; Barman, S M; Yates, B J

    2011-06-01

    The responses to vestibular stimulation of brain stem neurons that regulate sympathetic outflow and blood flow have been studied extensively in decerebrate preparations, but not in conscious animals. In the present study, we compared the responses of neurons in the rostral ventrolateral medulla (RVLM), a principal region of the brain stem involved in the regulation of blood pressure, to whole body rotations of conscious and decerebrate cats. In both preparations, RVLM neurons exhibited similar levels of spontaneous activity (median of ∼17 spikes/s). The firing of about half of the RVLM neurons recorded in decerebrate cats was modulated by rotations; these cells were activated by vertical tilts in a variety of directions, with response characteristics suggesting that their labyrinthine inputs originated in otolith organs. The activity of over one-third of RVLM neurons in decerebrate animals was altered by stimulation of baroreceptors; RVLM units with and without baroreceptor signals had similar responses to rotations. In contrast, only 6% of RVLM neurons studied in conscious cats exhibited cardiac-related activity, and the firing of just 1% of the cells was modulated by rotations. These data suggest that the brain stem circuitry mediating vestibulosympathetic reflexes is highly sensitive to changes in body position in space but that the responses to vestibular stimuli of neurons in the pathway are suppressed by higher brain centers in conscious animals. The findings also raise the possibility that autonomic responses to a variety of inputs, including those from the inner ear, could be gated according to behavioral context and attenuated when they are not necessary.

  9. Pneumomediastinum, pneumothorax and pneumoretroperitoneum following endoscopic retrieval of a tracheal foreign body from a cat.

    PubMed

    Zambelli, A B

    2006-03-01

    A 6-year-old entire male cat was presented with a 1-week history of severe dyspnoea without coughing. Upon auscultation, an inspiratory and particularly pronounced expiratory wheeze was noted, with severe dyspnoea. The minimum database was normal. Plain thoracic radiographs showed signs of a mural or intraluminal intrathoracic (T1-T4) tracheal narrowing. A dynamic collapsing trachea was ruled out using fluoroscopy. Bronchoscopy was performed and a dark green and brown spiculated foreign object was found just cranial to the carina. Following removal, the cat rapidly developed extensive truncal subcutaneous emphysema and oxygen-responsive dyspnoea and cyanosis. Follow-up radiographs demonstrated unilateral pneumothorax and lung collapse, marked pneumomediastinum and dissection of air through the tracheal wall. A thoracic drain was placed and the pneumothorax resolved rapidly. Follow-up radiographs demonstrated resolution of pneumothorax and development of extensive retroperitoneal air. The cat made an uneventful recovery. The foreign object was the calyx and stem of a flower. This article emphasises the importance of diagnostic imaging in the dyspnoeic patient, both for confirming initial suspicions of respiratory tract disease, and in managing and charting post-therapy resolution or complications.

  10. Intracellular pH and its regulation in isolated type I carotid body cells of the neonatal rat.

    PubMed Central

    Buckler, K J; Vaughan-Jones, R D; Peers, C; Nye, P C

    1991-01-01

    1. The dual-emission pH-sensitive fluoroprobe carboxy-SNARF-1 (carboxy-seminaptharhodofluor) was used to measure pHi in type I cells enzymically dispersed from the neonatal rat carotid body. 2. Steady-state pHi in cells bathed in a HEPES-buffered Tyrode solution (pH 7.4) was found to be remarkably alkaline (pHi = 7.77) whereas cells bathed in a CO2-HCO3(-)-buffered Tyrode solution (pH 7.4) had a more 'normal' pHi (pHi = 7.28). These observations were further substantiated by using an independent nullpoint test method to determine pHi. 3. Intracellular intrinsic buffering (beta, determined by acidifying the cell using an NH4Cl pre-pulse) was in the range 7-20 mM per pH unit and appeared to be dependent upon pHi with beta increasing as pHi decreased. 4. In cells bathed in a HEPES-buffered Tyrode solution, pHi recovery from an induced intracellular acid load (10 mM-NH4Cl pre-pulse) was inhibited by the Na(+)-H+ exchange inhibitor ethyl isopropyl amiloride (EIPA; 150 microM) or substitution of Nao+ with N-methyl-D-glucamine (NMG). Both EIPA and Nao+ removal also caused a rapid intracellular acidification, which in the case of Nao+ removal, was readily reversible. The rate of this acidification was similar for both Nao+ removal and EIPA addition. 5. Transferring cells from a HEPES-buffered Tyrode solution to one buffered with 5% CO2-HCO3- resulted in an intracellular acidification which was partially, or wholly, sustained. The rate of acidification upon transfer to CO2-HCO3- was considerably slowed by the membrane permeant carbonic anhydrase inhibitor, acetazolamide, thus indicating the presence of the enzyme in these cells. 6. In CO2-HCO3(-)-buffered Tyrode solution, pHi recovery from an intracellular acidosis (NH4+ pre-pulse) was only partially inhibited by EIPA or amiloride whereas Nao+ removal completely inhibited the recovery. The stilbene DIDS (4,4-diisothiocyanatostilbenedisulphonic acid, 200 microM) also partially inhibited pHi recovery following an induced

  11. Responses of aortic chemoreceptors before and after pneumothorax in the cat.

    PubMed

    Pokorski, M; Mokashi, A; Mulligan, E; Nishino, T; Lahiri, S

    1981-09-01

    That the response of aortic chemoreceptors to hypercapnia is considerably smaller than that of carotid chemoreceptors is well accepted, but the mechanism for the difference is not known. It has been suggested that surgical exposure of the carotid body may contribute to the difference. Accordingly, the response of aortic body chemoreceptors to CO2 would be expected to resemble quantitatively that of carotid chemoreceptors after exposure of the aortic bodies by pneumothorax. The effect of opening the chest on aortic and carotid chemoreceptor responses to several levels of arterial CO2 and O2 tension and arterial blood pressure were studied in anesthetized cats. The activity of aortic chemoreceptors increased in spite of a decreased stimulus level in the thoracic cavity after pneumothorax. The activity remained higher than the control at all levels of arterial CO2 and O2 tension and arterial blood pressure. However, the slopes of CO2 response curves, which were initially small, did not change after pneumothorax. Thus a change in the normal environment of the aortic bodies by experimental manipulation did not cause the aortic chemoreceptor responses to resemble those of carotid chemoreceptors.

  12. [Syncope and carotid paraganglioma].

    PubMed

    Bizueto-Rosas, Héctor; Salazar-Reyes, Anabel; Moran-Reyes, Ely Guadalupe; González-Arcos, Gregorio; Hernández-Pérez, Noemí A; Solorio-Rosette, Hugo F; Soto-Hernández, Gabriel

    2014-01-01

    Syncope is a medical emergency, which is more or less frequent. Its prevalence increases with age. It is defined as the loss of consciousness and postural tone resulting from a transient alteration of cerebral flow. It appears suddenly, but it does not leave behind any sequela or after-effects. Out of two groups, the neutrally mediated (or neuromediated) syncope, especially the one called carotid sinus hypersensitivity, is related to the carotid sinus paraganglioma. It is triggered by sinus pressure, which results in sudden death by overstimulation. In the next article, we show the case of a sexagenarian female patient with a disabling syncope and a 7 cm carotid body paraganglioma, which did not allow her the minimum movement of lateral dorsiflexion or extension of the neck. For this reason, the patient had to remain hospitalized, in a dorsal decubitus position with semiflexion of the neck. Before the surgery was practiced, a temporary pacemaker was used, and after the resection of the carotid body paraganglioma, in accordance to the patient's studies of cardiac electrophysiology, she was discharged without electrical nerve stimulation.

  13. Inhibition of adenylate cyclase attenuates muscarinic Ca²(+) signaling by a PKA-independent mechanism in rat carotid body Type I cells.

    PubMed

    Thompson, Carrie M; Wyatt, Christopher N

    2011-01-31

    Carotid body (CB) Type I cells respond to hypoxia by releasing excitatory and inhibitory neurotransmitters. This mechanism leads to increased firing of the carotid sinus nerve (CSN) which alters breathing to maintain blood gases within the physiological range. Acetylcholine targets both muscarinic and nicotinic receptors in the rat CB, acting postsynaptically on CSN and presynaptically on Type I cells. Muscarinic Ca²(+) signaling is inhibited by the activation of G(i)-coupled receptors including histamine H3 receptors. Here inhibition of adenylate cyclase with SQ22536 mimicked H3 receptor activation. Using Ca²(+) imaging techniques it was observed that inhibition of muscarinic Ca²(+) signaling was independent of protein kinase A (PKA) as PKA inhibitors H89 and KT5720 were without effect on the muscarinic Ca²(+) response. By contrast the Epac (exchange protein activated by cAMP) inhibitor brefeldin A inhibited muscarinic Ca²(+) signaling whereas the Epac activator 8-pCPT-2'-O-Me-cAMP-AM potentiated Ca²(+) signaling. Thus in Type I cells inhibition of adenylate cyclase inhibited muscarinic Ca²(+) signaling via a PKA-independent pathway that may rely upon modulation of Epac.

  14. Body composition and amino acid concentrations of select birds and mammals consumed by cats in northern and central California.

    PubMed

    Kremen, N A; Calvert, C C; Larsen, J A; Baldwin, R A; Hahn, T P; Fascetti, A J

    2013-03-01

    The diet of the feral domestic cat consists of primarily birds and small mammals, but the nutritional composition is relatively unknown. Because of the increasing popularity of natural diets for cats and other wild captive carnivores, the purpose of this study was to describe the body composition and AA concentrations of select birds and small mammals in northern and central California: wild-caught mice (n = 7), Norway rats (n = 2), roof rats (n = 2), voles (n = 4), moles (n = 2), gophers (n = 3), and birds (n = 4). Body water, crude fat (CFa), CP, ash, and AA composition for each specimen were determined. Results are reported as mean ± SD. All results are reported on a DM basis except body water (as-is basis) and AA (g/16 g N). Combined, carcasses had this mean composition: 67.35 ± 3.19% water, 11.72 ± 6.17% CFa, 62.19 ± 7.28% CP, and 14.83 ± 2.66% ash. Concentrations of Arg, Tau, Cys, and Met were 5.63 ± 0.46, 0.92 ± 0.33, 1.91 ± 0.89, and 1.82 ± 0.19 g/16 g N, respectively. Using NRC physiologic fuel values for CP, CFa, and carbohydrate by difference, the combined average energy content of the carcasses was 3,929 kcal/kg DM, but the fiber content was not determined. With the exception of mice and rats, little historical data exist regarding the body and AA composition of many of the species analyzed in this study. Wild-caught mice and rats were composed of less fat but more ash compared with previously reported data in their purpose-bred counterparts. The CP content of mice in this study was similar to previous reports in purpose-bred mice. The CP content of rats was similar or slightly greater compared with historical findings in purpose-bred rats. The N content of rats and AA concentrations on a per-N basis for both rats and mice were similar to previously published data on purpose-bred rodents. The discrepancies in nutrient composition, especially fat concentration, indicate that using purpose-bred animals to represent the diet of the feral domestic

  15. Tasting arterial blood: what do the carotid chemoreceptors sense?

    PubMed

    Prabhakhar, Nanduri R; Joyner, Michael J

    2014-01-01

    The carotid bodies are sensory organs that detect the chemical composition of the arterial blood. The carotid body sensory activity increases in response to arterial hypoxemia and the ensuing chemoreflex regulates vital homeostatic functions. Recent studies suggest that the carotid bodies might also sense arterial blood glucose and circulating insulin levels. This review focuses on how the carotid bodies sense O2, glucose, and insulin and some potential implications of these sensory functions on physiological regulation and in pathophysiological conditions. Emerging evidence suggests that carbon monoxide (CO)-regulated hydrogen sulfide (H2S), stemming from hypoxia, depolarizes type I cells by inhibiting certain K(+) channels, facilitates voltage-gated Ca(2+) influx leading to sensory excitation of the carotid body. Elevated CO and decreased H2S renders the carotid bodies insensitive to hypoxia resulting in attenuated ventilatory adaptations to high altitude hypoxia, whereas reduced CO and high H2S result in hypersensitivity of the carotid bodies to hypoxia and hypertension. Acute hypoglycemia augments the carotid body responses to hypoxia but that a prolonged lack of glucose in the carotid bodies can lead to a failure to sense hypoxia. Emerging evidence also indicates that carotid bodies might sense insulin directly independent of its effect on glucose, linking the carotid bodies to the pathophysiological consequences of the metabolic syndrome. How glucose and insulin interact with the CO-H2S signaling is an area of ongoing study.

  16. Tasting arterial blood: what do the carotid chemoreceptors sense?

    PubMed Central

    Prabhakhar, Nanduri R.; Joyner, Michael J.

    2015-01-01

    The carotid bodies are sensory organs that detect the chemical composition of the arterial blood. The carotid body sensory activity increases in response to arterial hypoxemia and the ensuing chemoreflex regulates vital homeostatic functions. Recent studies suggest that the carotid bodies might also sense arterial blood glucose and circulating insulin levels. This review focuses on how the carotid bodies sense O2, glucose, and insulin and some potential implications of these sensory functions on physiological regulation and in pathophysiological conditions. Emerging evidence suggests that carbon monoxide (CO)-regulated hydrogen sulfide (H2S), stemming from hypoxia, depolarizes type I cells by inhibiting certain K+ channels, facilitates voltage-gated Ca2+ influx leading to sensory excitation of the carotid body. Elevated CO and decreased H2S renders the carotid bodies insensitive to hypoxia resulting in attenuated ventilatory adaptations to high altitude hypoxia, whereas reduced CO and high H2S result in hypersensitivity of the carotid bodies to hypoxia and hypertension. Acute hypoglycemia augments the carotid body responses to hypoxia but that a prolonged lack of glucose in the carotid bodies can lead to a failure to sense hypoxia. Emerging evidence also indicates that carotid bodies might sense insulin directly independent of its effect on glucose, linking the carotid bodies to the pathophysiological consequences of the metabolic syndrome. How glucose and insulin interact with the CO-H2S signaling is an area of ongoing study. PMID:25642193

  17. Mean circulatory filling pressure during splanchnic nerve stimulation and whole-body hypoxia in the anaesthetized cat.

    PubMed Central

    Bower, E A; O'Donnell, C P

    1991-01-01

    1. Mean circulatory filling pressure (MCFP) was measured in cats under chloralose anaesthesia by obstruction of blood flow in the pulmonary artery. Pressures in the aorta, hepatic portal vein and right atrium were recorded, and MCFP was estimated from the value at which all three pressures became equal when blood was pumped from aorta to vena cava during circulatory arrest. Simultaneous equality was not attained at MCFP values below 5 mmHg. 2. In cats ventilated by positive pressure after administration of gallamine, MCFP was 9.7 +/- 0.3 mmHg (n = 14). The values of MCFP measured in six cats before and after administration of gallamine did not differ significantly. Change of blood volume altered MCFP linearly over the range 5-21 mmHg. Noradrenaline (7.5 micrograms kg-1 min-1) increased MCFP from 9.3 +/- 0.9 to 16.5 +/- 0.6 mmHg (n = 4), and phentolamine (2 mg kg-1) reduced it to 5.6 +/- 0.3 mmHg (n = 5). 3. Changes in MCFP were evoked at different circulating blood volumes by stimulation of the splanchnic sympathetic nerves and by whole-body hypoxia. Ablation of all splanchnic nerves reduced MCFP from 9.4 +/- 0.5 to 7.1 +/- 0.3 mmHg (n = 5) and stimulation of their distal ends at 10 Hz increased it by 4.1 +/- 0.4 mmHg (n = 4); similar increments were obtained at different blood volumes and initial values of MCFP. 4. Hypoxia increased MCFP by 0.23 mmHg per 1 mmHg fall in arterial oxygen tension below Pa,O2 56 mmHg (r = -0.86; n = 24). Similar increments were obtained at different blood volumes and initial values of MCFP. Ablation of all splanchnic nerves reduced the increments by 60%, and administration of phentolamine abolished them. PMID:1886068

  18. Microsurgical anatomy of the human carotid body (glomus caroticum): Features of its detailed topography, syntopy and morphology.

    PubMed

    Schulz, Sissy-Amelie; Wöhler, Aliona; Beutner, Dirk; Angelov, Doychin N

    2016-03-01

    The human glomus caroticum (GC) is not readily accessible during ordinary anatomical teaching courses because of insufficient time and difficulties encountered in the preparation. Accordingly, most anatomical descriptions of its location, relationship to neighboring structures, size and shape are supported only by drawings, but not by photographs. The aim of this study is to present the GC with all associated roots and branches. Following microscope-assisted dissection and precise photo-documentation, a detailed analysis of location, syntopy and morphology was performed. We carried out this study on 46 bifurcations of the common carotid artery (CCA) into the external (ECA) and internal (ICA) carotid arteries and identified the GC in 40 (91%) of them. We found significant variations regarding the location of the GC and its syntopy: GC was associated with CCA (42%), ECA (28%) and ICA (30%) lying on the medial or lateral surface (82% or 13%, respectively) or exactly in the middle (5%) of the bifurcation. The short and long diameter of its oval form varied from 1.0 × 2.0 to 5.0 × 5.0mm. Connections with the sympathetic trunk (100%), glossopharyngeal (93%), vagus (79%) and hypoglossal nerve (90%) could be established in 29 cadavers. We conclude that precise knowledge of this enormous variety might be very helpful not only to students in medicine and dentistry during anatomical dissection courses, but also to surgeons working in this field. Copyright © 2015 Elsevier GmbH. All rights reserved.

  19. Acetylcholine increases intracellular calcium of arterial chemoreceptor cells of adult cats.

    PubMed

    Shirahata, M; Fitzgerald, R S; Sham, J S

    1997-11-01

    Acetylcholine increases intracellular calcium of arterial chemoreceptor cells of adult cats. J. Neurophysiol. 78: 2388-2395, 1997. Several neurotransmitters have been reported to play important roles in the chemoreception of the carotid body. Among them acetylcholine (ACh) appears to be involved in excitatory processes in the cat carotid body. As one of the steps to elucidate possible roles of ACh in carotid body chemoreception in the cat, we examined the effect of ACh on intracellular calcium concentration ([Ca2+]i) of cultured carotid body cells. The carotid body from adult cats was dissociated and cultured for up to 2 wk. [Ca2+]i was measured from clusters of cells with a microfluorometric technique using Indo-1 AM. Experiments were performed at 37 degrees C, and cells were continuously superfused with modified Krebs solutions equilibrated with 5% CO2-16% O2-79% N2. ACh (100 mu M) caused a marked increase in [Ca2+]i in approximately 70% of clusters, and the responses to 1-300 mu M of ACh were concentration dependent. The magnitude and kinetics of the ACh response were mimicked by the application of nicotine, whereas muscarinic agonists, pilocarpine, and muscarine failed to evoke a similar response. ACh-induced increase in [Ca2+]i was dependent on extracellular Ca2+: it was greatly reduced or completely abolished by a transient removal of extracellular Ca2+. The response was consistently but only partially reduced by caffeine (5 mM) or nifedipine (10 mu M). The effect of mecamylamine (100 mu M) was inhibitory but small. Moreover, the increase in [Ca2+]i in response to ACh was also observed in some clusters that did not respond to high K (100 mM) Krebs. These results suggest that ACh increases [Ca2+]i of cultured carotid body cells by activating neuronal nicotinic ACh receptors, leading to Ca2+ influx via nicotinic channels. In addition, other pathways such as Ca2+ influx through L-type calcium channels, perhaps secondary to membrane depolarization, and Ca2

  20. The influence of acute hypoxia and carotid body denervation on thermoregulation during non-rapid eye movement sleep in the developing lamb.

    PubMed

    Symonds, M E; Andrews, D C; Johnson, P

    1999-11-01

    We investigated the influence of ambient temperature on the thermoregulatory response to hypoxia in developing lambs before (at 4 and 14 days of age) and after (17 and 30 days of age) carotid body denervation (CBD). Lambs were studied during non-rapid eye movement sleep at thermoneutral (23-15 C) and cool (10-5 C) ambient temperatures, during normoxia and acute hypoxia (inspired oxygen content of 13 %). Measurements of oxygen consumption, arterial partial pressures of O2 and CO2, colonic temperature, incidence of shivering and plasma concentrations of thyroid hormones, cortisol, insulin and glucose were made under each condition. Oxygen consumption was higher at cool compared with thermoneutral ambient temperatures and decreased during hypoxia during cooling at all stages. At 4 days of age, only one lamb shivered during cooling in normoxia, but 4 out of 12 lambs shivered during hypoxia and colonic temperature fell, significantly, by 0.2 C. At 14 days, 8 out of 12 lambs shivered during cooling, of which 6 continued to shiver during hypoxia but colonic temperature did not change significantly. Plasma triiodothyronine concentrations increased on cooling at 4 and 14 days, an affect that was inhibited by hypoxia at 4, but not 14 days of age. At 17 days of age, i.e. post-CBD, plasma thyroid hormone concentrations and oxygen consumption were lower during cold exposure compared with intact lambs at 14 days of age. In CBD lambs, imposing further hypoxia resulted in colonic temperature falling 0. 6 C during cooling, with only 2 out of 10 lambs shivering. Plasma glucose and insulin, but not cortisol, concentrations decreased during hypoxia, irrespective of age or CBD. It is concluded that hypoxia has an important influence on metabolism and thermoregulation, which is modulated by age and environmental conditions. Compromised carotid body function, in lambs older than 2 weeks of age, can result in severe hypoxia and thermoregulatory dysfunction even with modest environmental

  1. Oestradiol, but not genistein, inhibits the rise in food intake following gonadectomy in cats, but genistein is associated with an increase in lean body mass.

    PubMed

    Cave, N J; Backus, R C; Marks, S L; Klasing, K C

    2007-10-01

    The prevalence of obesity in domestic cats is increasing worldwide, and is strongly associated with gonadectomy. We have previously demonstrated the effectiveness of oestradiol in reducing food intake in both male and female neutered cats. This experiment was designed to test the hypothesis that oestradiol or genistein would prevent the increase in food intake following gonadectomy of male and female cats, and would prevent an increase in body fat mass. Three groups of eight cats each were surgically neutered then treated daily with either 0.5 mug oestradiol subcutaneously, 100 mg/kg genistein orally, or vehicle only. Effect of treatment on food intake, vaginal cytology and body weight were recorded, and body composition was assayed using the D(2)O isotopic dilution method. Neutering was followed by an increase in food intake, bodyweight and body fat mass in the control group, which were almost completely prevented by treatment with oestradiol (p < 0.001). Treatment with genistein had no effect on food intake or bodyweight increase, but was associated with a significant increase in lean body mass (p = 0.018), and significantly less body fat accumulation than the control group (p = 0.01). There were no significant differences in responses to treatment between sexes. These findings demonstrate the importance of gonadal oestrogen for the control of food intake in male and female cats, and suggest the provision of an oestrogenic compound could help prevent obesity following neutering. In addition, the findings of this study are consistent with observations in rodents of the efficacy of genistein in inhibiting adipogenesis and promoting lean body tissue development.

  2. Dietary fat and carbohydrate have different effects on body weight, energy expenditure, glucose homeostasis and behaviour in adult cats fed to energy requirement.

    PubMed

    Gooding, Margaret A; Atkinson, Jim L; Duncan, Ian J H; Niel, Lee; Shoveller, Anna K

    2015-01-01

    The effects of dietary carbohydrate and fat on feline health are not well understood. The effects of feeding diets moderately high in fat (HF; n 10; 30 % fat, 26 % carbohydrate as fed) or carbohydrate (HC; n 10; 11 % fat, 47 % carbohydrate), for 84 d, were investigated in healthy, adult cats (3·5 (sd 0·5) years). Data on indirect calorimetry, blood biomarkers, activity, play and cognition were collected at baseline, and at intervals throughout the study. Body composition was measured by dual-energy X-ray absorptiometry at baseline and on day 85. There were no significant main effects of diet on body weight and composition. When data were analysed over study day within diet, cats fed HF diets experienced a significant increase in body fat (P = 0·001) and body weight (P = 0·043) in contrast to cats consuming the HC diet that experienced no change in body fat or body weight (P = 0·762) throughout the study. Overall, energy expenditure was similar between diets (P = 0·356 (fasted), P = 0·086 (postprandial)) and respiratory quotient declined with exposure to the HF diet and increased with exposure to the HC diet (P < 0·001; fasted and postprandial). There was no difference in insulin sensitivity as an overall effect of diet (P = 0·266). Activity declined from baseline with exposure to both diets (HC: P = 0·002; HF: P = 0·01) but was not different between diets (P = 0·247). There was no effect of diet on play (P = 0·387) and cats consuming either the HF or HC diet did not successfully learn the cognitive test. Overall, cats adapt to dietary macronutrient content, and the implications of feeding HC and HF diets on risk for adiposity as driven by metabolic and behavioural mechanisms are discussed.

  3. Functional abolition of carotid body activity restores insulin action and glucose homeostasis in rats: key roles for visceral adipose tissue and the liver.

    PubMed

    Sacramento, Joana F; Ribeiro, Maria J; Rodrigues, Tiago; Olea, Elena; Melo, Bernardete F; Guarino, Maria P; Fonseca-Pinto, Rui; Ferreira, Cristiana R; Coelho, Joana; Obeso, Ana; Seiça, Raquel; Matafome, Paulo; Conde, Sílvia V

    2017-01-01

    We recently described that carotid body (CB) over-activation is involved in the aetiology of insulin resistance and arterial hypertension in animal models of the metabolic syndrome. Additionally, we have demonstrated that CB activity is increased in animal models of insulin resistance, and that carotid sinus nerve (CSN) resection prevents the development of insulin resistance and arterial hypertension induced by high-energy diets. Here, we tested whether the functional abolition of CB by CSN transection would reverse pre-established insulin resistance, dyslipidaemia, obesity, autonomic dysfunction and hypertension in animal models of the metabolic syndrome. The effect of CSN resection on insulin signalling pathways and tissue-specific glucose uptake was evaluated in skeletal muscle, adipose tissue and liver. Experiments were performed in male Wistar rats submitted to two high-energy diets: a high-fat diet, representing a model of insulin resistance, hypertension and obesity, and a high-sucrose diet, representing a lean model of insulin resistance and hypertension. Half of each group was submitted to chronic bilateral resection of the CSN. Age-matched control rats were also used. CSN resection normalised systemic sympathetic nervous system activity and reversed weight gain induced by high-energy diets. It also normalised plasma glucose and insulin levels, insulin sensitivity lipid profile, arterial pressure and endothelial function by improving glucose uptake by the liver and perienteric adipose tissue. We concluded that functional abolition of CB activity restores insulin sensitivity and glucose homeostasis by positively affecting insulin signalling pathways in visceral adipose tissue and liver.

  4. The Mitochondrial SDHD Gene Is Required for Early Embryogenesis, and Its Partial Deficiency Results in Persistent Carotid Body Glomus Cell Activation with Full Responsiveness to Hypoxia

    PubMed Central

    Piruat, José I.; Pintado, C. Oscar; Ortega-Sáenz, Patricia; Roche, Marta; López-Barneo, José

    2004-01-01

    The SDHD gene encodes one of the two membrane-anchoring proteins of the succinate dehydrogenase (complex II) of the mitochondrial electron transport chain. This gene has recently been proposed to be involved in oxygen sensing because mutations that cause loss of its function produce hereditary familiar paraganglioma, a tumor of the carotid body (CB), the main arterial chemoreceptor that senses oxygen levels in the blood. Here, we report the generation of a SDHD knockout mouse, which to our knowledge is the first mammalian model lacking a protein of the electron transport chain. Homozygous SDHD−/− animals die at early embryonic stages. Heterozygous SDHD+/− mice show a general, noncompensated deficiency of succinate dehydrogenase activity without alterations in body weight or major physiological dysfunction. The responsiveness to hypoxia of CBs from SDHD+/− mice remains intact, although the loss of an SDHD allele results in abnormal enhancement of resting CB activity due to a decrease of K+ conductance and persistent Ca2+ influx into glomus cells. This CB overactivity is linked to a subtle glomus cell hypertrophy and hyperplasia. These observations indicate that constitutive activation of SDHD+/− glomus cells precedes CB tumor transformation. They also suggest that, contrary to previous beliefs, mitochondrial complex II is not directly involved in CB oxygen sensing. PMID:15572694

  5. Purinergic signalling mediates bidirectional crosstalk between chemoreceptor type I and glial-like type II cells of the rat carotid body.

    PubMed

    Murali, Sindhubarathi; Nurse, Colin A

    2016-01-15

    Carotid body chemoreceptors are organized in clusters containing receptor type I and contiguous glial-like type II cells. While type I cells depolarize and release ATP during chemostimulation, the role of type II cells which express purinergic P2Y2 receptors (P2Y2Rs) and ATP-permeable pannexin-1 (Panx-1) channels, is unclear. Here, we show that in isolated rat chemoreceptor clusters, type I cell depolarization induced by hypoxia, hypercapnia, or high K(+) caused delayed intracellular Ca(2+) elevations (Δ[Ca(2+)]i) in nearby type II cells that were inhibited by the P2Y2R blocker suramin, or by the nucleoside hydrolase apyrase. Likewise, stimulation of P2Y2Rs on type II cells caused a delayed, secondary Δ[Ca(2+)]i in nearby type I cells that was inhibited by blockers of Panx-1 channels, adenosine A2A receptors and 5'-ectonucleotidase. We propose that reciprocal crosstalk between type I and type II cells contributes to sensory processing in the carotid body via purinergic signalling pathways. The mammalian carotid body (CB) is excited by blood-borne stimuli including hypoxia and acid hypercapnia, leading to respiratory and cardiovascular reflex responses. This chemosensory organ consists of innervated clusters of receptor type I cells, ensheathed by processes of adjacent glial-like type II cells. ATP is a major excitatory neurotransmitter released from type I cells and type II cells express purinergic P2Y2 receptors (P2Y2Rs), the activation of which leads to the opening of ATP-permeable, pannexin-1 (Panx-1) channels. While these properties support crosstalk between type I and type II cells during chemotransduction, direct evidence is lacking. To address this, we first exposed isolated rat chemoreceptor clusters to acute hypoxia, isohydric hypercapnia, or the depolarizing stimulus high K(+), and monitored intracellular [Ca(2+)] using Fura-2. As expected, these stimuli induced intracellular [Ca(2+)] elevations (Δ[Ca(2+)]i) in type I cells. Interestingly, however

  6. Carotid bypass for carotid occlusion.

    PubMed

    Hage, Ziad A; Behbahani, Mandana; Amin-Hanjani, Sepideh; Charbel, Fady T

    2015-07-01

    The 2-year risk of ipsilateral ischemic stroke following internal carotid artery occlusion (ICAO) in a patient undergoing maximal medical therapy is 5-8% per year. While medical therapy may reduce the risk of stroke, it does not completely eliminate it. Since the 1985 extracranial-intracranial (EC-IC) bypass study, additional trials have been conducted to further investigate the usefulness of EC-IC bypass surgery in more selected patients with cerebral ischemia and impaired hemodynamic reserve. These important studies will be briefly reviewed in this article, as well as a discussion regarding the utility of bypass surgery for ICAO in current clinical practice. In addition, a short discussion regarding the pathophysiology of carotid occlusion will be presented. We will also highlight our own institutional patient selection criteria based on the latest methods for hemodynamic assessment, as well as our intraoperative flow assisted surgical techniques (FAST), and post-operative patient follow-up.

  7. CT angiography ofthe carotid arteries.

    PubMed

    Prokop, M; Waaijer, A; Kreuzer, S

    2004-01-01

    The introduction of multislice scanning has made CT angiography (CTA) a serious competitor to MR angiography (MRA) as a second line method for the evaluation of the carotid arteries. For optimum display of the morphology of stenoses, it is necessary to apply the thinnest possible section collimation (ideally [symbol: see text] 1.25mm). While the scan range is limited for single slice CTA, it is possible to cover the whole supraaortic circulation from the aortic arch to the intracranial vessels using multislice scanning. Timing of contrast injection is important, however, the injection technique for carotid CTA is more forgiving than for other body regions. Image evaluation is mainly based on axial sections and curved planar reformations (CPR). Other techniques only serve as an adjunct to better be able to demonstrate the findings. Most potential pitfalls can be avoided by using the appropriate technique. CTA has been shown to have a pooled sensitivity of 95% and specificity of 98% for the detection of >70% stenoses, even if only older single-slice techniques are used. Differentiation between lipid, fibrous and calcified plaques may be possible, especially with multislice scanning. Multislice CTA can in addition detect tandem stenoses in the region of the carotid origin from the aorta, the carotid siphon, and the intracranial portion of the carotids. CT is able to provide a comprehensive evaluation of patients with acute stroke by using a combined approach of pre-contrast CT to detect hemorrhage and manifest infarction, CT brain perfusion measurements to differentiate between penumbra and infarct and CTA to detect the occluded vessel as well as potential concomitant carotid abnormalities. In summary, carotid CTA has come of age and can be used to quantify stenoses more precisely than ultrasound, to detect tandem stenoses and for the workup of acute stroke patients. The learning objectives include learning how to chose acquisition parameters for carotid CTA, how to

  8. Carotid artery stenting versus carotid endarterectomy.

    PubMed

    Nanna, Michael G; Gomes, Paulina; Njoh, Roland F; Ward, Charisse; Attaran, Robert R; Mena, Carlos

    2016-09-01

    Stroke remains a significant contributor to morbidity and mortality in developed countries. Carotid artery stenosis is a major cause of stroke. Advances in medical therapy, surgical technique and endovascular maturation has resulted in options for the treatment of carotid stenosis. Here, we present a review of carotid artery stenting and carotid endarterectomy as it applies to trials comparing and contrasting the two treatment options. We also explore the intricacies surrounding reimbursement of these treatment strategies in the USA.

  9. Modulation of junctional conductance between rat carotid body glomus cells by hypoxia, cAMP and acidity.

    PubMed

    Abudara, V; Eyzaguirre, C

    1998-05-04

    Short-term cultures of glomus cells (up to seven days), were employed to study intercellular electrical communications. Bidirectional electric coupling was established under current clamping after impaling two adjacent glomus cells with microelectrodes, and alternate stimulation and recording. Their resting potential (Vm) and input resistance (Ro) were thus measured. Both coupled cells were then voltage clamped at a level between their Vms. Current pulses applied to either cell elicited a transjunctional voltage (Vj) and current (Ij), used to calculate the junctional conductance (Gj). Gj was 1.52+/-0.29 nS (mean+/-S.E.; n=147). Vj linearly influenced Gj, suggesting ohmic junctions. Gj was not affected by Vm in 50% of the cases. However, there was Vm-dependence in the others, but voltage changes had to be large (>+/-40 mV from the Vm). Therefore, physiologically or pharmacologically induced glomus cell depolarization or hyperpolarization may not significantly affect intercellular coupling unless there are large variations in Vm. Hypoxia (induced by Na2S2O4 1 mM or 100% N2) decreased Gj in 60-80% of the pairs while producing tighter coupling in the rest. Similar effects were obtained when the medium was acidified with lactic acid 1-10 mM. Cobalt chloride (3 mM) prevented, diminished or reversed the changes in Gj observed during low PO2, suggesting that [Ca2+]i changes are important in hypoxic uncoupling. However, non-specific cationic effects of Co2+ have not been ruled out. Applications of the membrane-permeant dB-cAMP 1 mM tightened coupling in almost all cell pairs. This is important because endogenous cAMP increases during hypoxia. Our results suggest that multiple factors modulate junctional conductance between glomus cells. Changes in Gj by 'natural' stimuli and/or cAMP may play an important role in chemoreception, especially in titrating the release of transmitters toward the carotid nerve terminals. Copyright 1998 Elsevier Science B.V.

  10. The cell bodies of origin of sympathetic and sensory axons in some skin and muscle nerves of the cat hindlimb.

    PubMed

    McLachlan, E M; Jänig, W

    1983-02-20

    Cell bodies of sensory and sympathetic axons projecting to skin and skeletal muscle of the cat hindlimb have been labeled retrogradely with horseradish peroxidase (HRP) in order to study location, size, and numbers of the somata of these neurons. HRP was applied to the freshly transected axons of nerves supplying hairy skin (superficial peroneal, SP; sural, Su), hairy and hairless skin of the paw (medial plantar, MP), or skeletal muscle (gastrocnemius-soleus, GS). Serial sections of lumbosacral dorsal root and sympathetic ganglia were studied after standard histochemical processing. Additionally, the numbers of myelinated fibers in the same nerves were determined. All sensory somata and 99.4% of sympathetic cell bodies were located ipsilaterally. Sensory somata were commonly restricted to two adjacent dorsal root ganglia (usually L6-7 for SP, MP; L7-S1 for Su, GS). Although sympathetic somata were more widely distributed rostrocaudally, their maximum frequency always occurred in the segmental ganglia immediately rostral to the sensory outflows, i.e., corresponding to rami communicantes grisei. Dimensions of sympathetic somata varied little between populations projecting to different tissues and were unimodally distributed. The size distributions of sensory somata were characterized by a peak between 10 and 20 microns radius, similar to sympathetic somata, and a varying smaller number of cells ranging up to 60 microns radius. Each nerve had a characteristic distribution profile of afferent somata. A population of very small cells was only present in GS, while the largest sensory somata in GS and MP were bigger than those in SP and Su. Numerical analysis of the data disclosed the characteristic composition of both myelinated and unmyelinated fibers in each nerve studied.

  11. The CamKKβ Inhibitor STO609 Causes Artefacts in Calcium Imaging and Selectively Inhibits BKCa in Mouse Carotid Body Type I Cells.

    PubMed

    Jurcsisn, Jennifer G; Pye, Richard L; Ali, Jon; Barr, Barbara L; Wyatt, Christopher N

    2015-01-01

    It has previously been reported that AMP-activated protein kinase (AMPK) may be critical for hypoxic chemotransduction in carotid body type I cells. This study sought to determine the importance of the regulatory upstream kinase of AMPK, CamKKβ, in the acute response to hypoxia in isolated mouse type I cells.Initial data indicated several previously unreported artefacts associated with using the CamKKβ inhibitor STO609 and Ca(2+) imaging techniques. Most importantly Fura-2 and X-Rhod1 imaging revealed that STO609 quenched emission fluorescence even in the absence of intracellular Ca(2+) ([Ca(2+)](I)). Furthermore, STO609 (100 μM) rapidly inhibited outward macroscopic currents and this inhibition was abolished in the presence of the selective BK(Ca) inhibitor paxilline.Taken together these data suggest that ST0609 should be used with caution during Ca(2+) imaging studies as it can directly interact with Ca(2+) binding dyes. The rapid inhibitory effect of STO609 on BK(Ca) was unexpected as the majority of studies using this compound required an incubation of approximately 10 min to inhibit the kinase. Furthermore, as AMPK activation inhibits BK(Ca), inhibiting AMPK's upstream kinases would, if anything, be predicted to have the opposite effect on BK(Ca). Future work will determine if the inhibition of BK(Ca) is via CamKKβ or via an off target action of STO609 on the channel itself.

  12. Gene Expression Profiling Supports the Neural Crest Origin of Adult Rodent Carotid Body Stem Cells and Identifies CD10 as a Marker for Mesectoderm-Committed Progenitors.

    PubMed

    Navarro-Guerrero, Elena; Platero-Luengo, Aida; Linares-Clemente, Pedro; Cases, Ildefonso; López-Barneo, José; Pardal, Ricardo

    2016-06-01

    Neural stem cells (NSCs) are promising tools for understanding nervous system plasticity and repair, but their use is hampered by the lack of markers suitable for their prospective isolation and characterization. The carotid body (CB) contains a population of peripheral NSCs, which support organ growth during acclimatization to hypoxia. We have set up CB neurosphere (NS) cultures enriched in differentiated neuronal (glomus) cells versus undifferentiated progenitors to investigate molecular hallmarks of cell classes within the CB stem cell (CBSC) niche. Microarray gene expression analysis in NS is compatible with CBSCs being neural crest derived-multipotent progenitor cells able to sustain CB growth upon exposure to hypoxia. Moreover, we have identified CD10 as a marker suitable for isolation of a population of CB mesectoderm-committed progenitor cells. CD10 + cells are resting in normoxia, and during hypoxia they are activated to proliferate and to eventually complete maturation into mesectodermal cells, thus participating in the angiogenesis necessary for CB growth. Our results shed light into the molecular and cellular mechanisms involved in CBSC fate choice, favoring a potential use of these cells for cell therapy. Stem Cells 2016;34:1637-1650. © 2016 AlphaMed Press.

  13. Carotid artery anatomy (image)

    MedlinePlus

    There are four carotid arteries, two on each side of the neck: right and left internal carotid arteries, and right and left external carotid arteries. The carotid arteries deliver oxygen-rich blood from the heart to the head and brain.

  14. Directionality derived from differential sensitivity to monaural and binaural cues in the cat's medial geniculate body.

    PubMed

    Samson, F K; Barone, P; Irons, W A; Clarey, J C; Poirier, P; Imig, T J

    2000-09-01

    Azimuth tuning of high-frequency neurons in the primary auditory cortex (AI) is known to depend on binaural disparity and monaural spectral (pinna) cues present in broadband noise bursts. Single-unit response patterns differ according to binaural interactions, strength of monaural excitatory input from each ear, and azimuth sensitivity to monaural stimulation. The latter characteristic has been used as a gauge of neural sensitivity to monaural spectral directional cues. Azimuth sensitivity may depend predominantly on binaural disparity cues, exclusively on monaural spectral cues, or on both. The primary goal of this study was to determine whether each cortical response pattern corresponds to a similar pattern in the medial geniculate body (MGB) or whether some patterns are unique to the cortex. Single-unit responses were recorded from the ventral nucleus (Vn) and lateral part of the posterior group of thalamic nuclei (Po), tonotopic subdivisions of the MGB. Responses to free-field presentation of noise bursts that varied in azimuth and sound pressure level were obtained using methods identical to those used previously in field AI. Many units were azimuth sensitive, i.e., they responded well at some azimuths, and poorly, if at all, at others. These were studied further by obtaining responses to monaural noise stimulation, approximated by reversible plugging of one ear. Monaural directional (MD) cells were sensitive to the azimuth of monaural noise stimulation, whereas binaural directional (BD) cells were either insensitive to its azimuth or monaurally unresponsive. Thus BD and MD cells show differential sensitivity to monaural spectral cues. Monaural azimuth sensitivity could not be used to interpret the spectral sensitivity of predominantly binaural cells that exhibited strong binaural facilitation because they were either unresponsive or poorly responsive to monaural stimulation. The available evidence suggests that some such cells are sensitive to spectral cues

  15. Dependence of carotid chemosensory responses on metabolic substrates.

    PubMed

    Spergel, D; Lahiri, S; Wilson, D F

    1992-11-20

    The dependence of the carotid chemosensory response to hypoxia on metabolic substrate and the hypothesis that lactic acidosis is essential for O2 chemoreception were tested. Effects of 3 types of substrate (glucose, glutamate and a mixture of amino acids) on the response to hypoxia (perfusate flow interruption) were measured (n = 33 carotid bodies). The response to nicotine (n = 25) was used to determine whether these effects were exclusive to the hypoxic response. The cat carotid body was perfused and superfused in vitro with modified Tyrode solution (pO2 > 400 Torr, pCO2 < 1 Torr, pH = 7.4) at 36 degrees C containing a given substrate for at least 15 min prior to flow interruption or nicotine injection. Without substrate, responses to flow interruption (n = 4) and nicotine (n = 2) were irreversibly depressed. With glucose, responses to flow interruption (n = 13) and nicotine (n = 8) increased in a concentration-dependent fashion. Glutamate (42 mM) alone (n = 11) or a mixture of amino acids (4.2 mM) plus 5.5 mM glucose (n = 12) substituted for 11 mM glucose (n = 10). Thus, glutamate (42 mM), or a mixture of amino acids (4.2 mM) or a high concentration of glucose (11 mM) can support chemosensory responses to flow interruption and nicotine. Since glutamate undergoes oxidative deamination to alpha-ketoglutarate without lactic acid production, O2 chemoreception does not depend on lactic acidosis.

  16. Autonomic control of the cardiovascular system in the cat during hypoxemia.

    PubMed

    Fitzgerald, Robert S; Dehghani, Gholam Abbas; Kiihl, Samara

    2013-03-01

    This study aimed to determine the roles played by the autonomic interoreceptors, the carotid bodies (cbs) and the aortic bodies (abs) in anesthetized, paralyzed, artificially ventilated cats' response to systemic hypoxemia. Four 15min challenges stimulated each of 15 animals: (1) hypoxic hypoxia (10%O₂ in N₂; HH) in the intact (int) cat where both abs and cbs sent neural traffic to the nucleus tractus solitarius (NTS); (2) carbon monoxide hypoxia (30%O₂ in N₂ with the addition of CO; COH) in the intact cat where only the abs sent neural traffic to the NTS; (3) HH in the cat after transection of both aortic depressor nerves, resecting the aortic bodies (HHabr), where only the cbs sent neural traffic to the NTS; (4) COH to the abr cat where neither abs nor cbs sent neural traffic to the NTS. Cardiac output (C.O.), contractility (dP/dt(MAX)), systolic/diastolic pressures, aortic blood pressure, total peripheral resistance, pulmonary arterial pressure, and pulmonary vascular resistance (PVR) were measured. When both cbs and abs were active the maximum increases were observed except for PVR which decreased. Some variables showed the cbs to have a greater effect than the abs. The abs proved to be important during some challenges for maintaining blood pressure. The data support the critically important role for the chemoreceptor-sympathetic nervous system connection during hypoxemia for maintaining viable homeostasis, with some differences between the cbs and the abs.

  17. Is plasticity within the retrotrapezoid nucleus responsible for the recovery of the PCO2 set‐point after carotid body denervation in rats?

    PubMed Central

    Basting, Tyler M.; Abe, Chikara; Viar, Kenneth E.; Stornetta, Ruth L.

    2016-01-01

    Key points Arterial PCO2 is kept constant via breathing adjustments elicited, at least partly, by central chemoreceptors (CCRs) and the carotid bodies (CBs).The CBs may be active in a normal oxygen environment because their removal reduces breathing. Thereafter, breathing slowly returns to normal. In the present study, we investigated whether an increase in the activity of CCRs accounts for this return.One week after CB excision, the hypoxic ventilatory reflex was greatly reduced as expected, whereas ventilation and blood gases at rest under normoxia were normal.Optogenetic inhibition of Phox2b‐expressing neurons including the retrotrapezoid nucleus, a cluster of CCRs, reduced breathing proportionally to arterial pH. The hypopnoea was greater after CB excision but only in a normal or hypoxic environment. The difference could be simply explained by the loss of fast feedback from the CBs.We conclude that, in rats, CB denervation may not produce CCR plasticity. We also question whether the transient hypoventilation elicited by CB denervation means that these afferents are active under normoxia. Abstract Carotid body denervation (CBD) causes hypoventilation and increases the arterial PCO2 set‐point; these effects eventually subside. The hypoventilation is attributed to reduced CB afferent activity and the PCO2 set‐point recovery to CNS plasticity. In the present study, we investigated whether the retrotrapezoid nucleus (RTN), a group of non‐catecholaminergic Phox2b‐expressing central respiratory chemoreceptors (CCRs), is the site of such plasticity. We evaluated the contribution of the RTN to breathing frequency (F R), tidal volume (V T) and minute volume (V E) by inhibiting this nucleus optogenetically for 10 s (archaerhodopsinT3.0) in unanaesthetized rats breathing various levels of O2 and/or CO2. The measurements were made in seven rats before and 6–7 days after CBD and were repeated in seven sham‐operated rats. Seven days post‐CBD, blood gases and

  18. Evidence that 5-HT stimulates intracellular Ca(2+) signalling and activates pannexin-1 currents in type II cells of the rat carotid body.

    PubMed

    Murali, Sindhubarathi; Zhang, Min; Nurse, Colin A

    2017-07-01

    5-HT is a neuromodulator released from carotid body (CB) chemoreceptor (type I) cells and facilitates the sensory discharge following chronic intermittent hypoxia (CIH). In the present study, we show that, in addition to type I cells, adjacent glial-like type II cells express functional, ketanserin-sensitive 5-HT2 receptors, and their stimulation increases cytoplasmic Ca(2+) derived from intracellular stores. In type II cells, 5-HT activated a ketanserin-sensitive inward current (I5-HT ) that was similar to that (IUTP ) activated by the P2Y2R agonist, UTP. As previously shown for IUTP , I5-HT was inhibited by BAPTA-AM and carbenoxolone (5 μm), a putative blocker of ATP-permeable pannexin (Panx)-1 channels; IUTP was reversibly inhibited by the specific Panx-1 mimetic peptide channel blocker, (10) Panx peptide. Paracrine stimulation of type II cells by 5-HT, leading to ATP release via Panx-1 channels, may contribute to CB excitability, especially in pathophysiological conditions associated with CIH (e.g. obstructive sleep apnoea). Carotid body (CB) chemoreceptor (type I) cells can synthesize and release 5-HT and increased autocrine-paracrine 5-HT2 receptor signalling contributes to sensory long-term facilitation during chronic intermittent hypoxia (CIH). However, recent studies suggest that adjacent glial-like type II cells can respond to CB paracrine signals by elevating intracellular calcium (Δ[Ca(2+) ]i ) and activating carbenoxolone-sensitive, ATP-permeable, pannexin (Panx)-1-like channels. In the present study, using dissociated rat CB cultures, we found that 5-HT induced Δ[Ca(2+) ]i responses in a subpopulation of type I cells, as well as in most (∼67%) type II cells identified by their sensitivity to the P2Y2 receptor agonist, UTP. The 5-HT-induced Ca(2+) response in type II cells was dose-dependent (EC50 ∼183 nm) and largely inhibited by the 5-HT2A receptor blocker, ketanserin (1 μm), and also arose mainly from intracellular stores. 5-HT also

  19. Body Condition Scores and Evaluation of Feeding Habits of Dogs and Cats at a Low Cost Veterinary Clinic and a General Practice.

    PubMed

    Sapowicz, Stephanie A; Linder, Deborah E; Freeman, Lisa M

    2016-01-01

    This study assessed body condition scores (BCS) and feeding habits for dogs and cats. Eighty-six cats and 229 dogs (and their owners) were enrolled from 2 clinics: a low cost clinic (n = 149) and a general practice (n = 166). BCS and body weight were recorded. Owners completed a survey which included animal age, sex, and breed; owner demographics; and feeding practices (e.g., diet, rationale for feeding practices). Owners from the low cost clinic had a significantly lower income (P < 0.001) and education (P < 0.001) compared to those from the general practice. Animals from the low cost clinic were younger (P < 0.001) and dogs were less likely to be neutered (P < 0.001). Overweight prevalence was 55% overall (P = 0.083), with a significantly higher prevalence in the general practice for cats (44% versus 66%; P = 0.046), but not for dogs (58% versus 53%; P = 0.230). Multivariate analysis showed that only neuter status was significantly associated with BCS (P = 0.004). Veterinarians were the most common source of nutritional information, though lack of accurate nutrition knowledge was common among all participants. These findings support the need for enhanced communication about optimal BCS and nutrition regardless of socioeconomic status.

  20. Body Condition Scores and Evaluation of Feeding Habits of Dogs and Cats at a Low Cost Veterinary Clinic and a General Practice

    PubMed Central

    2016-01-01

    This study assessed body condition scores (BCS) and feeding habits for dogs and cats. Eighty-six cats and 229 dogs (and their owners) were enrolled from 2 clinics: a low cost clinic (n = 149) and a general practice (n = 166). BCS and body weight were recorded. Owners completed a survey which included animal age, sex, and breed; owner demographics; and feeding practices (e.g., diet, rationale for feeding practices). Owners from the low cost clinic had a significantly lower income (P < 0.001) and education (P < 0.001) compared to those from the general practice. Animals from the low cost clinic were younger (P < 0.001) and dogs were less likely to be neutered (P < 0.001). Overweight prevalence was 55% overall (P = 0.083), with a significantly higher prevalence in the general practice for cats (44% versus 66%; P = 0.046), but not for dogs (58% versus 53%; P = 0.230). Multivariate analysis showed that only neuter status was significantly associated with BCS (P = 0.004). Veterinarians were the most common source of nutritional information, though lack of accurate nutrition knowledge was common among all participants. These findings support the need for enhanced communication about optimal BCS and nutrition regardless of socioeconomic status. PMID:27722198

  1. Molecular identification and functional role of voltage-gated sodium channels in rat carotid body chemoreceptor cells. Regulation of expression by chronic hypoxia in vivo.

    PubMed

    Caceres, Ana I; Obeso, Ana; Gonzalez, Constancio; Rocher, Asuncion

    2007-07-01

    We have assessed the expression, molecular identification and functional role of Na+ channels (Na(v)) in carotid bodies (CB) obtained from normoxic and chronically hypoxic adult rats. Veratridine evoked release of catecholamines (CA) from an in vitro preparation of intact CBs obtained from normoxic animals, the response being Ca2+ and Na+-dependent and sensitive to tetrodotoxin (TTX). TTX inhibited by 25-50% the CA release response evoked by graded hypoxia. Immunoblot assays demonstrated the presence of Na(v)alpha-subunit (c. 220 kDa) in crude homogenates from rat CBs, being evident an up-regulation (60%) of this protein in the CBs obtained from chronically hypoxic rats (10% O2; 7 days). This up-regulation was accompanied by an enhanced TTX-sensitive release response to veratridine, and by an enhanced ventilatory response to acute hypoxic stimuli. RT-PCR studies demonstrated the expression of mRNA for Na(v)1.1, Na(v)1.2, Na(v)1.3, Na(v)1.6 and Na(v)1.7 isoforms. At least three isoforms, Na(v)1.1, Na(v)1.3 and Na(v)1.6 co-localized with tyrosine hydroxylase in all chemoreceptor cells. RT-PCR and immunocytochemistry indicated that Na(v)1.1 isoform was up-regulated by chronic hypoxia in chemoreceptor cells. We conclude that Na(v) up-regulation represents an adaptive mechanism to increase chemoreceptor sensitivity during acclimatization to sustained hypoxia as evidenced by enhanced ventilatory responses to acute hypoxic tests.

  2. Carotid baroreflex control of heart rate is enhanced, while control of mean arterial pressure is preserved during whole body heat stress in young healthy men.

    PubMed

    Krnjajic, Davor; Allen, Dustin R; Butts, Cory L; Keller, David M

    2016-10-01

    Whole body heat stress (WBH) results in numerous cardiovascular alterations that ultimately reduce orthostatic tolerance. While impaired carotid baroreflex (CBR) function during WBH has been reported as a potential reason for this decrement, study design considerations may limit interpretation of previous findings. We sought to test the hypothesis that CBR function is unaltered during WBH. CBR function was assessed in 10 healthy male subjects (age: 26 ± 3; height: 185 ± 7 cm; weight: 82 ± 10 kg; BMI: 24 ± 3 kg/m(2); means ± SD) using 5-s trials of neck pressure (+45, +30, and +15 Torr) and neck suction (-20, -40, -60, and -80 Torr) during normothermia (NT) and passive WBH (Δ core temp ∼1°C). Analyses of stimulus response curves (four-parameter logistic model) for CBR control of heart rate (CBR-HR) and mean arterial pressure (CBR-MAP), as well as separate two-way ANOVA of the hypotensive and hypertensive stimuli (factor 1: thermal condition, factor 2: chamber pressure), were performed. For CBR-HR, maximal gain was increased during WBH (-0.73 ± 0.11) compared with NT (-0.39 ± 0.04, mean ± SE, P = 0.03). In addition, the CBR-HR responding range was increased during WBH (33 ± 5) compared with NT (19 ± 2 bpm, P = 0.03). Separate analysis of hypertensive stimulation revealed enhanced HR responses during WBH at -40, -60, and -80 Torr (condition × chamber pressure interaction, P = 0.049) compared with NT. For CBR-MAP, both logistic analysis and separate two-way ANOVA revealed no differences during WBH. Therefore, in response to passive WBH, CBR control of heart rate (enhanced) and arterial pressure (no change) is well preserved. Copyright © 2016 the American Physiological Society.

  3. BDNF and AMPA receptors in the cNTS modulate the hyperglycemic reflex after local carotid body NaCN stimulation.

    PubMed

    Cuéllar, R; Montero, S; Luquín, S; García-Estrada, J; Melnikov, V; Virgen-Ortiz, A; Lemus, M; Pineda-Lemus, M; de Álvarez-Buylla, E

    2017-07-01

    The application of sodium cyanide (NaCN) to the carotid body receptors (CBR) (CBR stimulation) induces rapid blood hyperglycemia and an increase in brain glucose retention. The commissural nucleus tractus solitarius (cNTS) is an essential relay nucleus in this hyperglycemic reflex; it receives glutamatergic afferents (that also release brain derived neurotrophic factor, BDNF) from the nodose-petrosal ganglia that relays CBR information. Previous work showed that AMPA in NTS blocks hyperglycemia and brain glucose retention after CBR stimulation. In contrast, BDNF, which attenuates glutamatergic AMPA currents in NTS, enhances these glycemic responses. Here we investigated the combined effects of BDNF and AMPA (and their antagonists) in NTS on the glycemic responses to CBR stimulation. Microinjections of BDNF plus AMPA into the cNTS before CBR stimulation in anesthetized rats, induced blood hyperglycemia and an increase in brain arteriovenous (a-v) of blood glucose concentration difference, which we infer is due to increased brain glucose retention. By contrast, the microinjection of the TrkB antagonist K252a plus AMPA abolished the glycemic responses to CBR stimulation similar to what is observed after AMPA pretreatments. In BDNF plus AMPA microinjections preceding CBR stimulation, the number of c-fos immunoreactive cNTS neurons increased. In contrast, in the rats microinjected with K252a plus AMPA in NTS, before CBR stimulation, c-fos expression in cNTS decreased. The expression of AMPA receptors GluR2/3 did not change in any of the studied groups. These results indicate that BDNF in cNTS plays a key role in the modulation of the hyperglycemic reflex initiated by CBR stimulation. Copyright © 2017. Published by Elsevier B.V.

  4. P2Y2 receptor activation opens pannexin-1 channels in rat carotid body type II cells: potential role in amplifying the neurotransmitter ATP.

    PubMed

    Zhang, Min; Piskuric, Nikol A; Vollmer, Cathy; Nurse, Colin A

    2012-09-01

    Signal processing in the carotid body (CB) is initiated at receptor glomus (or type I) cells which depolarize and release the excitatory neurotransmitter ATP during chemoexcitation by hypoxia and acid hypercapnia. Glomus cell clusters (GCs) occur in intimate association with glia-like type II cells which express purinergic P2Y2 receptors (P2Y2Rs) but their function is unclear. Here we immunolocalize the gap junction-like protein channel pannexin-1 (Panx-1) in type II cells and show Panx-1 mRNA expression in the rat CB. As expected, type II cell activation within or near isolated GCs by P2Y2R agonists, ATP and UTP (100 μm), induced a rise in intracellular [Ca(2+)]. Moreover in perforated-patch whole cell recordings from type II cells, these agonists caused a prolonged depolarization and a concentration-dependent, delayed opening of non-selective ion channels that was prevented by Panx-1 blockers, carbenoxolone (5 μm) and 4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid (DIDS; 10 μm). Because Panx-1 channels serve as conduits for ATP release, we hypothesized that paracrine, type II cell P2Y2R activation leads to ATP-induced ATP release. In proof-of-principle experiments we used co-cultured chemoafferent petrosal neurones (PNs), which express P2X2/3 purinoceptors, as sensitive biosensors of ATP released from type II cells. In several cases, UTP activation of type II cells within or near GCs led to depolarization or increased firing in nearby PNs, and the effect was reversibly abolished by the selective P2X2/3 receptor blocker, pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS; 10 μm). We propose that CB type II cells may function as ATP amplifiers during chemotransduction via paracrine activation of P2Y2Rs and Panx-1 channels.

  5. Increase in cytosolic Ca2+ produced by hypoxia and other depolarizing stimuli activates a non-selective cation channel in chemoreceptor cells of rat carotid body

    PubMed Central

    Kang, Dawon; Wang, Jiaju; Hogan, James O; Vennekens, Rudi; Freichel, Marc; White, Carl; Kim, Donghee

    2014-01-01

    The current model of O2 sensing by carotid body chemoreceptor (glomus) cells is that hypoxia inhibits the outward K+ current and causes cell depolarization, Ca2+ influx via voltage-dependent Ca2+ channels and a rise in intracellular [Ca2+] ([Ca2+]i). Here we show that hypoxia (<5% O2), in addition to inhibiting the two-pore domain K+ channels TASK-1/3 (TASK), indirectly activates an ∼20 pS channel in isolated glomus cells. The 20 pS channel was permeable to K+, Na+ and Cs+ but not to Cl− or Ca2+. The 20 pS channel was not sensitive to voltage. Inhibition of TASK by external acid, depolarization of glomus cells with high external KCl (20 mm) or opening of the Ca2+ channel with FPL64176 activated the 20 pS channel when 1 mm Ca2+ was present in the external solution. Ca2+ (10 μm) applied to the cytosolic side of inside-out patches activated the 20 pS channel. The threshold [Ca2+]i for activation of the 20 pS channel in cell-attached patches was ∼200 nm. The reversal potential of the 20 pS channel was estimated to be −28 mV. Our results reveal a sequential mechanism in which hypoxia (<5% O2) first inhibits the K+ conductance and then activates a Na+-permeable, non-selective cation channel via depolarization-induced rise in [Ca2+]i. Our results suggest that inhibition of K+ efflux and stimulation of Na+ influx both contribute to the depolarization of glomus cells during moderate to severe hypoxia. PMID:24591572

  6. Oxygen and mitochondrial inhibitors modulate both monomeric and heteromeric TASK-1 and TASK-3 channels in mouse carotid body type-1 cells

    PubMed Central

    Turner, Philip J; Buckler, Keith J

    2013-01-01

    In rat arterial chemoreceptors, background potassium channels play an important role in maintaining resting membrane potential and promoting depolarization and excitation in response to hypoxia or acidosis. It has been suggested that these channels are a heterodimer of TASK-1 and TASK-3 based on their similarity to heterologously expressed TASK-1/3 fusion proteins. In this study, we sought to confirm the identity of these channels through germline ablation of Task-1 (Kcnk3) and Task-3 (Kcnk9) in mice. Background K-channels were abundant in carotid body type-1 cells from wild-type mice and comparable to those previously described in rat type-1 cells with a main conductance state of 33 pS. This channel was absent from both Task-1−/− and Task-3−/− cells. In its place we observed a larger (38 pS) K+-channel in Task-1−/− cells and a smaller (18 pS) K+-channel in Task-3−/− cells. None of these channels were observed in Task-1−/−/Task-3−/− double knock-out mice. We therefore conclude that the predominant background K-channel in wild-type mice is a TASK-1/TASK-3 heterodimer, whereas that in Task-1−/− mice is TASK-3 and, conversely, that in Task-3−/− mice is TASK-1. All three forms of TASK channel in type-1 cells were inhibited by hypoxia, cyanide and the uncoupler FCCP, but the greatest sensitivity was seen in TASK-1 and TASK-1/TASK-3 channels. In summary, the background K-channel in type-1 cells is predominantly a TASK-1/TASK-3 heterodimer. Although both TASK-1 and TASK-3 are able to couple to the oxygen and metabolism sensing pathways present in type-1 cells, channels containing TASK-1 appear to be more sensitive. PMID:24042502

  7. Body CT (CAT Scan)

    MedlinePlus

    ... during the procedure. Metal objects, including jewelry, eyeglasses, dentures and hairpins, may affect the CT images and ... may increase the risk of an unusual adverse effect. Women should always inform their physician and the ...

  8. Body CT (CAT Scan)

    MedlinePlus

    ... lives. CT has been shown to be a cost-effective imaging tool for a wide range of ... accredited facilities database . This website does not provide cost information. The costs for specific medical imaging tests, ...

  9. Carotid baroreflex responsiveness in heat-stressed humans

    NASA Technical Reports Server (NTRS)

    Crandall, C. G.

    2000-01-01

    The effects of whole body heating on human baroreflex function are relatively unknown. The purpose of this project was to identify whether whole body heating reduces the maximal slope of the carotid baroreflex. In 12 subjects, carotid-vasomotor and carotid-cardiac baroreflex responsiveness were assessed in normothermia and during whole body heating. Whole body heating increased sublingual temperature (from 36.4 +/- 0.1 to 37.4 +/- 0.1 degrees C, P < 0.01) and increased heart rate (from 59 +/- 3 to 83 +/- 3 beats/min, P < 0. 01), whereas mean arterial blood pressure (MAP) was slightly decreased (from 88 +/- 2 to 83 +/- 2 mmHg, P < 0.01). Carotid-vasomotor and carotid-cardiac responsiveness were assessed by identifying the maximal gain of MAP and heart rate to R wave-triggered changes in carotid sinus transmural pressure. Whole body heating significantly decreased the responsiveness of the carotid-vasomotor baroreflex (from -0.20 +/- 0.02 to -0.13 +/- 0.02 mmHg/mmHg, P < 0.01) without altering the responsiveness of the carotid-cardiac baroreflex (from -0.40 +/- 0.05 to -0.36 +/- 0.02 beats x min(-1) x mmHg(-1), P = 0.21). Carotid-vasomotor and carotid-cardiac baroreflex curves were shifted downward and upward, respectively, to accommodate the decrease in blood pressure and increase in heart rate that accompanied the heat stress. Moreover, the operating point of the carotid-cardiac baroreflex was shifted closer to threshold (P = 0.02) by the heat stress. Reduced carotid-vasomotor baroreflex responsiveness, coupled with a reduction in the functional reserve for the carotid baroreflex to increase heart rate during a hypotensive challenge, may contribute to increased susceptibility to orthostatic intolerance during a heat stress.

  10. Carotid baroreflex responsiveness in heat-stressed humans

    NASA Technical Reports Server (NTRS)

    Crandall, C. G.

    2000-01-01

    The effects of whole body heating on human baroreflex function are relatively unknown. The purpose of this project was to identify whether whole body heating reduces the maximal slope of the carotid baroreflex. In 12 subjects, carotid-vasomotor and carotid-cardiac baroreflex responsiveness were assessed in normothermia and during whole body heating. Whole body heating increased sublingual temperature (from 36.4 +/- 0.1 to 37.4 +/- 0.1 degrees C, P < 0.01) and increased heart rate (from 59 +/- 3 to 83 +/- 3 beats/min, P < 0. 01), whereas mean arterial blood pressure (MAP) was slightly decreased (from 88 +/- 2 to 83 +/- 2 mmHg, P < 0.01). Carotid-vasomotor and carotid-cardiac responsiveness were assessed by identifying the maximal gain of MAP and heart rate to R wave-triggered changes in carotid sinus transmural pressure. Whole body heating significantly decreased the responsiveness of the carotid-vasomotor baroreflex (from -0.20 +/- 0.02 to -0.13 +/- 0.02 mmHg/mmHg, P < 0.01) without altering the responsiveness of the carotid-cardiac baroreflex (from -0.40 +/- 0.05 to -0.36 +/- 0.02 beats x min(-1) x mmHg(-1), P = 0.21). Carotid-vasomotor and carotid-cardiac baroreflex curves were shifted downward and upward, respectively, to accommodate the decrease in blood pressure and increase in heart rate that accompanied the heat stress. Moreover, the operating point of the carotid-cardiac baroreflex was shifted closer to threshold (P = 0.02) by the heat stress. Reduced carotid-vasomotor baroreflex responsiveness, coupled with a reduction in the functional reserve for the carotid baroreflex to increase heart rate during a hypotensive challenge, may contribute to increased susceptibility to orthostatic intolerance during a heat stress.

  11. [Conditioned reflex changes in the intra-analyzer interaction of the afferent inputs from the lateral geniculate body and pulvinar thalami in the cerebral cortex of cats].

    PubMed

    Shumikhina, S I

    1986-01-01

    Paired heterogeneous stimulation of the lateral geniculate body (LGB) and pulvinar (Pulv) as a conditioned stimulus of alimentary instrumental conditioned reflex (CR), resulted in a change of relations between afferent inputs from LGB and Pulv to the visual and associative cortex of cats. At stimulation of LGB preceding by 40 ms, facilitation of the response to testing Pulv stimulation observed in untrained cats, appeared only at the beginning of the learning and was suppressed by the end of elaboration, when the amplitude of the response to the conditioning LGB stimulation greatly increased. In the process of CR elaboration (in the middle of learning), Pulv stimulation preceding by 40 ms facilitated the response to the testing LGB stimulation and simultaneously increased the amplitude of the response to the conditioning Pulv stimulation.

  12. Carotid Artery Disease

    MedlinePlus

    ... brain with blood. If you have carotid artery disease, the arteries become narrow, usually because of atherosclerosis. ... one of the causes of stroke. Carotid artery disease often does not cause symptoms, but there are ...

  13. Carotid artery surgery - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100124.htm Carotid artery surgery - series—Normal anatomy To use the sharing ... out of 4 Overview There are four carotid arteries, with a pair located on each side of ...

  14. A Placebo-Controlled Study on the Effects of the Glucagon-Like Peptide-1 Mimetic, Exenatide, on Insulin Secretion, Body Composition and Adipokines in Obese, Client-Owned Cats

    PubMed Central

    Hoelmkjaer, Kirsten M.; Wewer Albrechtsen, Nicolai J.; Holst, Jens J.; Cronin, Anna M.; Nielsen, Dorte H.; Mandrup-Poulsen, Thomas; Bjornvad, Charlotte R.

    2016-01-01

    Glucagon-like Peptide-1 mimetics increase insulin secretion and reduces body weight in humans. In lean, healthy cats, short-term treatment has produced similar results, whereas the effect in obese cats or with extended duration of treatment is unknown. Here, prolonged (12 weeks) treatment with the Glucagon-like Peptide-1 mimetic, exenatide, was evaluated in 12 obese, but otherwise healthy, client-owned cats. Cats were randomized to exenatide (1.0 μg/kg) or placebo treatment twice daily for 12 weeks. The primary endpoint was changes in insulin concentration; the secondary endpoints were glucose homeostasis, body weight, body composition as measured by dual-energy x-ray absorptiometry and overall safety. An intravenous glucose tolerance test (1 g/kg body weight) was conducted at week 0 and week 12. Exenatide did not change the insulin concentration, plasma glucose concentration or glucose tolerance (P>0.05 for all). Exenatide tended to reduce body weight on continued normal feeding. Median relative weight loss after 12 weeks was 5.1% (range 1.7 to 8.4%) in the exenatide group versus 3.2% (range -5.3 to 5.7%) in the placebo group (P = 0.10). Body composition and adipokine levels were unaffected by exenatide (P>0.05). Twelve weeks of exenatide was well-tolerated, with only two cases of mild, self-limiting gastrointestinal signs and a single case of mild hypoglycemia. The long-term insulinotropic effect of exenatide appeared less pronounced in obese cats compared to previous short-term studies in lean cats. Further investigations are required to fully elucidate the effect on insulin secretion, glucose tolerance and body weight in obese cats. PMID:27136422

  15. Effects of the removal of extracellular Ca2+ on [Ca2+]i responses to FCCP and acetate in carotid body glomus cells of adult rabbits.

    PubMed

    Sato, M

    1997-09-12

    The effects of the removal of extracellular Ca2+ on the responses of cytosolic concentrations of Ca2+ ([Ca2+]i) to acidic stimuli, a protonophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) and an organic acid acetate, were examined in clusters of cultured carotid body glomus cells of adult rabbits using fura-2 microfluorometry. Application of FCCP (1 microM) induced an increase in [Ca2+]i (mean +/- S.E.M., 108 +/- 14%). After withdrawal of the protonophore the increased [Ca2+]i returned slowly to a resting level. The [Ca2+]i response was attenuated by an inorganic Ca2+ channel antagonist Ni2+ (2 mM) by 81 +/- 4%, and by an L-type voltage-gated Ca2+ channel antagonist D600 (10 microM) by 53 +/- 13%. The removal of extracellular Ca2+ eliminated the [Ca2+]i response in 71% of the tested cells (n = 17), and depressed it by 68 +/- 6% in the rest. Recovery following stimulation with FCCP in the absence of Ca2+ reversibly produced a rapid and large rise in [Ca2+]i, referred to as a [Ca2+]i rise after Ca2+-free/FCCP. The magnitude of a [Ca2+]i rise after Ca2+-free/FCCP (285 +/- 28%, P < 0.05) was larger than that of an increase in [Ca2+]i induced by FCCP in the presence of Ca2+ and had a correlation with the intensity of the suppression of the [Ca2+]i response by Ca2+ removal. A [Ca2+]i rise after Ca2+-free/FCCP was inhibited mostly by D600. Similarly, recovery following exposure to acetate in the absence of Ca2+ caused a rise in [Ca2+]i, referred to as a [Ca2+]i rise after Ca2+-free/acetate which was sensitive to D600. The magnitude of the [Ca2+]i rise was larger than that of a change in [Ca2+]i caused by acetate in the presence of Ca2+. These results suggest that FCCP-induced increase in [Ca2+]i was, in most cells, due to Ca2+ influx via L-type voltage-gated Ca2+ channels and, in some cells, due to both Ca2+ influx and Ca2+ release from internal Ca2+ pool. The removal of extracellular Ca2+ might modify [Ca2+]i responses to acidic stimuli, causing [Ca2+]i

  16. P2Y2 receptor activation opens pannexin-1 channels in rat carotid body type II cells: potential role in amplifying the neurotransmitter ATP

    PubMed Central

    Zhang, Min; Piskuric, Nikol A; Vollmer, Cathy; Nurse, Colin A

    2012-01-01

    Signal processing in the carotid body (CB) is initiated at receptor glomus (or type I) cells which depolarize and release the excitatory neurotransmitter ATP during chemoexcitation by hypoxia and acid hypercapnia. Glomus cell clusters (GCs) occur in intimate association with glia-like type II cells which express purinergic P2Y2 receptors (P2Y2Rs) but their function is unclear. Here we immunolocalize the gap junction-like protein channel pannexin-1 (Panx-1) in type II cells and show Panx-1 mRNA expression in the rat CB. As expected, type II cell activation within or near isolated GCs by P2Y2R agonists, ATP and UTP (100 μm), induced a rise in intracellular [Ca2+]. Moreover in perforated-patch whole cell recordings from type II cells, these agonists caused a prolonged depolarization and a concentration-dependent, delayed opening of non-selective ion channels that was prevented by Panx-1 blockers, carbenoxolone (5 μm) and 4,4′-diisothiocyano-2,2′-stilbenedisulfonic acid (DIDS; 10 μm). Because Panx-1 channels serve as conduits for ATP release, we hypothesized that paracrine, type II cell P2Y2R activation leads to ATP-induced ATP release. In proof-of-principle experiments we used co-cultured chemoafferent petrosal neurones (PNs), which express P2X2/3 purinoceptors, as sensitive biosensors of ATP released from type II cells. In several cases, UTP activation of type II cells within or near GCs led to depolarization or increased firing in nearby PNs, and the effect was reversibly abolished by the selective P2X2/3 receptor blocker, pyridoxalphosphate-6-azophenyl-2′,4′-disulphonic acid (PPADS; 10 μm). We propose that CB type II cells may function as ATP amplifiers during chemotransduction via paracrine activation of P2Y2Rs and Panx-1 channels. PMID:22733659

  17. Evaluation of carotid intima-media thickness and carotid arterial stiffness in children with adenotonsillar hypertrophy.

    PubMed

    Çiftel, Murat; Demir, Berrin; Kozan, Günay; Yılmaz, Osman; Kahveci, Hasan; Kılıç, Ömer

    2016-02-01

    Adenotonsillar hypertrophy can produce cardiopulmonary disease in children. However, it is unclear whether adenotonsillar hypertrophy causes atherosclerosis. This study evaluated carotid intimamedia thickness and carotid arterial stiffness in children with adenotonsillar hypertrophy. The study included 40 children with adenotonsillar hypertrophy (age: 5-10 years) and 36 healthy children with similar age and body mass index. Systolic blood pressure, diastolic blood pressure, and pulse pressure were measured in all subjects. Carotid intima-media thickness, carotid arterial systolic diameter, and carotid arterial diastolic diameter were measured using a high-resolution ultrasound device. Based on these measurements, carotid arterial strain, carotid artery distensibility, beta stiffness index, and elasticity modulus were calculated. Carotid intima-media thickness was greater in children with adenotonsillar hypertrophy (0.36±0.05 mm vs. 0.34±0.04 mm, P=0.02) compared to healthy controls. Beta stiffness index (3.01±1.22 vs. 2.98±0.98, P=0.85), elasticity modulus (231.39±99.23 vs. 226.46±83.20, P=0.88), carotid arterial strain (0.17±0.06 vs. 0.17±0.04, P=0.95), and carotid artery distensibility (13.14±3.88 vs. 12.92±3.84, P=0.75) were similar between children with adenotonsillar hypertrophy and the healthy controls. The present study revealed increased carotid intima-media thickness in children with adenotonsillar hypertrophy. The risk of subclinical atherosclerosis may be higher in children with adenotonsillar hypertrophy.

  18. Metronidazole neurotoxicosis in two cats.

    PubMed

    Caylor, K B; Cassimatis, M K

    2001-01-01

    Two cats were presented for neurological dysfunction from suspected metronidazole toxicity. One cat was receiving 111 mg/kg body weight per day of metronidazole for 9 weeks. After 9 weeks, the dose was increased to 222 mg/kg body weight per day, and 2 days later the cat began to experience progressive neurological signs that culminated in generalized seizures. The second cat was receiving metronidazole at a total dose of 58 mg/kg body weight per day for 6 months. This cat experienced acute onset of ataxia and alteration in mentation. Laboratory evaluations in both cases were without significant findings. The neurological signs in both cats resolved within days of initiating supportive therapy and withdrawal of the drug. This report describes the two cases and discusses the etiology of metronidazole neurotoxicosis.

  19. Metabolic determinants of body weight after cats were fed a low-carbohydrate high-protein diet or a high-carbohydrate low-protein diet ad libitum for 8 wk.

    PubMed

    Coradini, M; Rand, J S; Morton, J M; Rawlings, J M

    2014-10-01

    Overweight and obese conditions are common in cats and are associated with the development of a number of diseases. Knowledge of metabolic determinants and predictors of weight gain may enable better preventative strategies for obesity in cats. Lean, healthy cats were fed either a low-carbohydrate high-protein diet (n 16) or a high-carbohydrate low-protein (n 16) diet ad libitum for 8 wk. Potential determinants and predictors of final body weight assessed were body fat and lean masses, energy required for maintenance, energy requirements above maintenance for each kilogram of weight gain, insulin sensitivity index, fasting, mean 24-h and peak plasma glucose, insulin, and leptin concentrations, and fasting and mean 24-h serum adiponectin concentrations. In cats fed the low-carbohydrate high-protein diet, after adjusting for initial body weight, those with higher energy requirements for weight gain and higher fasting glucose concentration had higher final body weights (P ≤ 0.01). Predicted final body weights using initial body weight, fasting glucose and mean 24-h insulin concentrations (partial R(2) 37.3%) were imprecise. An equation using just initial body weight and fasting glucose concentration would be of more practical value, but was marginally less precise. In cats fed the high-carbohydrate low-protein diet, those with lower fasting leptin concentration initially had higher final body weights (P = 0.01). Predicted final body weights using initial body weight, energy requirements for maintenance, total body fat percentage and fasting leptin concentration (partial R(2) 39.2%) were reasonably precise. Further studies are warranted to confirm these findings and to improve the precision of predicted final body weights. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Diabetes mellitus in cats.

    PubMed

    Rand, Jacquie S; Marshall, Rhett D

    2005-01-01

    Feline diabetes is a multifactorial disease with genetic and environmental factors, including diet, excess body weight, and physical inactivity, involved in its pathogenesis. Although type 2 diabetes is most common in cats, most cats are insulin-dependent at the time of diagnosis. If good glycemic control can be achieved early after diagnosis, a substantial proportion of diabetic cats go into clinical remission. Diabetic remission may be facilitated by using a low-carbohydrate-high-protein diet combined with a long-acting insulin, such as glargine, administered twice daily. Rather than just controlling clinical signs, these new treatment modalities make curing feline diabetes a realistic goal for practitioners.

  1. Living with Carotid Artery Disease

    MedlinePlus

    ... from the NHLBI on Twitter. Living With Carotid Artery Disease If you have carotid artery disease, you can take steps to manage the ... treatment plan, and getting ongoing care. Having carotid artery disease raises your risk of having a stroke . ...

  2. What Is Carotid Artery Disease?

    MedlinePlus

    ... from the NHLBI on Twitter. What Is Carotid Artery Disease? Carotid artery disease is a disease in ... blood to your face, scalp, and neck. Carotid Arteries Figure A shows the location of the right ...

  3. In vitro activation of cyclo-oxygenase in the rabbit carotid body: effect of its blockade on [3H]catecholamine release.

    PubMed Central

    Gómez-Niño, A; Almaraz, L; González, C

    1994-01-01

    The release of prostaglandin E2 (PGE2) from rabbit carotid bodies (CBs) incubated in basal conditions (PO2 approximately 132 mmHg; PCO2 approximately 33 mmHg; pH = 7.42) amounts to 94.4 +/- 10.1 pg (mg protein)-1 (10 min)-1 (mean +/- S.E.M.). Incubation of the CB in a hypoxic solution (PO2 approximately 46 mmHg) produced a significant 40% increase (P < 0.05) in the release of PGE2. Indomethacin (2 microM) prevented the hypoxia-induced release of PGE2. Sensory plus sympathetic denervation of the CB 4 days prior to the experiments did not modify either basal or low PO2-induced PGE2 release, indicating that intraglomic nerve endings are not significant sources for the PGE2 released. Incubation of the CB in an acidic-hypercapnic solution (PO2 approximately 132 mmHg; PCO2 approximately 132 mmHg; pH = 6.60) or in a high K(+)-containing solution (35 mM) was also effective in promoting an increase in the outflow of PGE2 from the organs. The release of [3H]catecholamines ([3H]CA) from the CB elicited by incubating the organs in low PO2 solutions (PO2 ranged between 66 and 13 mmHg) was potentiated by two inhibitors of cyclo-oxygenase, acetylsalicylic acid (ASA, 100 microM) and indomethacin (2 microM). The effect persisted after chronic denervation of the organ. The secretory response elicited by acidic stimuli was also augmented by cyclo-oxygenase inhibitors. Thus, [3H]CA release elicited by incubating the CBs in the acidic-hypercapnic solution increased by 300% in the presence of indomethacin (2 microM), and ASA (100 microM) more than doubled the release induced by dinitrophenol (100 microM), a protonophore that mimics an acidic stimulus. Indomethacin, but not ASA, moderately increased the high K(+)-evoked [3H]CA release. The effect of indomethacin on the release of [3H]CA elicited by acidic and hypoxic stimuli was reversed by PGE2 in a dose-dependent manner (0.3-300 nM). These results show that low PO2 and high PCO2-low pH, the natural stimuli to the CB, as well as high

  4. Altered expression of adenosine A1 and A2A receptors in the carotid body and nucleus tractus solitarius of adult male and female rats following neonatal caffeine treatment.

    PubMed

    Bairam, Aida; Joseph, Vincent; Lajeunesse, Yves; Kinkead, Richard

    2009-09-01

    Neonatal caffeine treatment (adenosine receptor antagonist, 15 mg/kg/day, between postnatal days 3 and 12) affects respiratory patterns in adult male but not female rats as shown by an increase in the respiratory frequency in the early phase of response to hypoxia and an increase in the tidal volume in the late phase of response. Here, we tested the hypothesis that these changes are correlated with modified expression of adenosine receptors in the chemoreflex pathway. Carotid bodies, nucleus tractus solitarii, and superior cervical ganglia were collected from 3-month-old male and female rats that were either naive (not manipulated during the neonatal period) or treated with caffeine (NCT) or water (NWT) between postnatal days 3 and 12 by gavage. Western blot analysis was used to assess the expression of adenosine A(1) and A(2A) receptors and tyrosine hydroxylase, the rate-limiting enzyme for dopamine synthesis. In male rats, there was a 37% increase in the level of A(2A) receptor and a 17% decrease in tyrosine hydroxylase in the carotid body of NCT (p<0.001) as compared to NWT rats. In the nucleus tractus solitarius, we found a 13% and 19% decrease in A(1) receptor expression in NWT and NCT rats (p<0.01), respectively, compared to naive rats. In the superior cervical ganglion, there was no change in A(1) receptor, A(2A) receptor, and tyrosine hydroxylase expression. In female rats, the only changes observed were decreases of 12% and 15% in A(1) receptor levels in the nucleus tractus solitarius of NWT and NCT rats (p<0.01), respectively, compared to naive rats. We conclude that NCT induces long-term changes in the adenosine receptor system. These changes may partially explain the modifications of the respiratory pattern induced by NCT in adults. The increased expression of the adenosine A(2A) receptor (specific to male rats), combined with the decreased tyrosine hydroxylase expression in the carotid body, suggests that NCT affects adenosine-dopamine interactions

  5. Lumbosacral agenesis in a cat

    PubMed Central

    Hybki, Gabrielle C; Murphy, Lisa A; Marchi, Joseph P; Patlogar, Jeffrey E; Brisson, Jennifer O; Nakamura, Reid K

    2016-01-01

    Case summary Lumbosacral agenesis is a rare congenital condition reported in children. We report a 17-week-old female domestic shorthair cat with lumbosacral agenesis on whole-body radiographs. The cat was euthanized shortly thereafter presentation. A necropsy was not permitted. Relevance and novel information This is the first reported feline case of lumbosacral agenesis. PMID:28491410

  6. Cat Batiks.

    ERIC Educational Resources Information Center

    Buban, Marcia H.

    1998-01-01

    Discusses an art activity where fourth-grade students created backgrounds using melted paraffin and a variety of paints for their cat batik/collage. Explains that after the students created their backgrounds, they assembled their paper cats for the collage using smaller shapes glued together and wax to add texture for fur. (CMK)

  7. Cat Batiks.

    ERIC Educational Resources Information Center

    Buban, Marcia H.

    1998-01-01

    Discusses an art activity where fourth-grade students created backgrounds using melted paraffin and a variety of paints for their cat batik/collage. Explains that after the students created their backgrounds, they assembled their paper cats for the collage using smaller shapes glued together and wax to add texture for fur. (CMK)

  8. Muscle spindle responses to horizontal support surface perturbation in the anesthetized cat: insights into the role of autogenic feedback in whole body postural control

    PubMed Central

    Nardelli, Paul; Cope, Timothy C.; Nichols, T. Richard

    2012-01-01

    Intact cats and humans respond to support surface perturbations with broadly tuned, directionally sensitive muscle activation. These muscle responses are further sensitive to initial stance widths (distance between feet) and perturbation velocity. The sensory origins driving these responses are not known, and conflicting hypotheses are prevalent in the literature. We hypothesize that the direction-, stance-width-, and velocity-sensitive muscle response during support surface perturbations is driven largely by rapid autogenic proprioceptive pathways. The primary objective of this study was to obtain direct evidence for our hypothesis by establishing that muscle spindle receptors in the intact limb can provide appropriate information to drive the muscle response to whole body postural perturbations. Our second objective was to determine if spindle recordings from the intact limb generate the heightened sensitivity to small perturbations that has been reported in isolated muscle experiments. Maintenance of this heightened sensitivity would indicate that muscle spindles are highly proficient at detecting even small disturbances, suggesting they can provide efficient feedback about changing postural conditions. We performed intraaxonal recordings from muscle spindles in anesthetized cats during horizontal, hindlimb perturbations. We indeed found that muscle spindle afferents in the intact limb generate broadly tuned but directionally sensitive activation patterns. These afferents were also sensitive to initial stance widths and perturbation velocities. Finally, we found that afferents in the intact limb have heightened sensitivity to small perturbations. We conclude that muscle spindle afferents provide an array of important information about biomechanics and perturbation characteristics highlighting their potential importance in generating appropriate muscular response during a postural disturbance. PMID:22673334

  9. Muscle spindle responses to horizontal support surface perturbation in the anesthetized cat: insights into the role of autogenic feedback in whole body postural control.

    PubMed

    Honeycutt, Claire F; Nardelli, Paul; Cope, Timothy C; Nichols, T Richard

    2012-09-01

    Intact cats and humans respond to support surface perturbations with broadly tuned, directionally sensitive muscle activation. These muscle responses are further sensitive to initial stance widths (distance between feet) and perturbation velocity. The sensory origins driving these responses are not known, and conflicting hypotheses are prevalent in the literature. We hypothesize that the direction-, stance-width-, and velocity-sensitive muscle response during support surface perturbations is driven largely by rapid autogenic proprioceptive pathways. The primary objective of this study was to obtain direct evidence for our hypothesis by establishing that muscle spindle receptors in the intact limb can provide appropriate information to drive the muscle response to whole body postural perturbations. Our second objective was to determine if spindle recordings from the intact limb generate the heightened sensitivity to small perturbations that has been reported in isolated muscle experiments. Maintenance of this heightened sensitivity would indicate that muscle spindles are highly proficient at detecting even small disturbances, suggesting they can provide efficient feedback about changing postural conditions. We performed intraaxonal recordings from muscle spindles in anesthetized cats during horizontal, hindlimb perturbations. We indeed found that muscle spindle afferents in the intact limb generate broadly tuned but directionally sensitive activation patterns. These afferents were also sensitive to initial stance widths and perturbation velocities. Finally, we found that afferents in the intact limb have heightened sensitivity to small perturbations. We conclude that muscle spindle afferents provide an array of important information about biomechanics and perturbation characteristics highlighting their potential importance in generating appropriate muscular response during a postural disturbance.

  10. Photoacoustic imaging of carotid artery atherosclerosis

    NASA Astrophysics Data System (ADS)

    Kruizinga, Pieter; van der Steen, Antonius F. W.; de Jong, Nico; Springeling, Geert; Robertus, Jan Lukas; van der Lugt, Aad; van Soest, Gijs

    2014-11-01

    We introduce a method for photoacoustic imaging of the carotid artery, tailored toward detection of lipid-rich atherosclerotic lesions. A common human carotid artery was obtained at autopsy, embedded in a neck mimicking phantom and imaged with a multimodality imaging system using interstitial illumination. Light was delivered through a 1.25-mm-diameter optical probe that can be placed in the pharynx, allowing the carotid artery to be illuminated from within the body. Ultrasound imaging and photoacoustic signal detection is achieved by an external 8-MHz linear array coupled to an ultrasound imaging system. Spectroscopic analysis of photoacoustic images obtained in the wavelength range from 1130 to 1250 nm revealed plaque-specific lipid accumulation in the collagen structure of the artery wall. These spectroscopic findings were confirmed by histology.

  11. The relationship between carotid blood pressure reactivity to mental stress and carotid intima-media thickness.

    PubMed

    Spartano, Nicole L; Augustine, Jacqueline A; Lefferts, Wesley K; Gump, Brooks B; Heffernan, Kevin S

    2014-10-01

    Brachial blood pressure (BP) reactivity to stress predicts large artery damage and future cardiovascular (CV) events. Central BP is an emerging risk factor associated with target organ damage (TOD). Currently, little is known about the central BP response to mental stress and its association to TOD. Twenty-five healthy, non-obese adults completed a computerized mental stress test. Brachial and carotid systolic (S)BP reactivity to stress were calculated as SBP during stress minus resting SBP. Resting carotid intima-media thickness (IMT) was also measured. Carotid SBP reactivity to stress was significantly associated with carotid IMT, independent of age, sex, body mass index, non-high density lipoprotein cholesterol and brachial SBP reactivity to stress (r = 0.386, p < 0.05). The relationship between carotid SBP reactivity and carotid IMT suggests that the central BP response to stress may prove to be an early risk marker for potential subclinical TOD. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  12. Carotid artery disease

    MedlinePlus

    ... a stroke recover most or all of their functions. Others die of the stroke itself or from complications. About half of people ... patients with extracranial carotid and vertebral artery disease: executive summary: ... American Association of Neuroscience Nurses, American Association ...

  13. Carotid dissection (image)

    MedlinePlus

    ... This leaking of blood into the artery wall (dissection) may cause a clot to form, reducing blood ... the neck, which means stroke secondary to carotid dissection may occur in young people as well as ...

  14. Astronomy CATS

    NASA Astrophysics Data System (ADS)

    Brissenden, Gina; Prather, Edward E.; Impey, Chris

    2012-08-01

    The Center for Astronomy Education's (CAE's) NSF-funded Collaboration of Astronomy Teaching Scholars (CATS) Program is a grassroots multi-institutional effort to increase the capacity for astronomy education research and improve science literacy in the United States.Our primary target population is the 500,000 college students who each year enroll in an introductory general education (a breadth requirement for non-science majors) Earth, Astronomy, and Space Science (EASS) course (Fraknoi 2001, AGI 2006).An equally important population for our efforts is the individuals who are, or will be, teaching these students. In this chapter, we will briefly discuss the goals of CAE and CATS, the varied personnel that make up the CATS collective, the diverse projects we've undertaken, and the many challenges we have had to work through to make CATS a success.

  15. Hearing disorders in cats.

    PubMed

    Strain, George M

    2017-03-01

    Practical relevance: Auditory function is a sense that is central to life for cats - being important in situational awareness of potential predators, pursuit of prey, and for communication with conspecifics, humans and other species. Deafness in cats is most frequently the result of a genetic disorder, strongly associated with white fur and blue eyes, but may also result from acquired causes such as advancing age, ototoxic drugs, infection, environmental noise and physical trauma. Deafness can be sensorineural, where there is loss of cochlear hair cells, or conductive, where sound is muffled on its way to the inner ear. Clinical challenges: Establishing whether a cat is deaf can be difficult as behavioral testing of hearing is subjective and does not reliably detect unilateral deafness. Brainstem auditory evoked response testing is an objective measure but is limited in its availability. Currently, sensorineural deafness is irreversible because no treatments are available to restore lost hair cells. Conductive hearing loss can usually be treated, although full hearing recovery following otitis media may take weeks as the body clears the middle ear of debris. Evidence base: The author draws on the published literature and his extensive research on clinical aspects and molecular genetics of deafness, principally in companion animals, to review types and forms of deafness in cats. He also discusses current diagnostic approaches and provides brief advice for managing cats with hearing loss.

  16. [Carotid ultrasonography: evaluation of carotid ultrasonography].

    PubMed

    Taniuchi, Ryosui

    2007-02-01

    Carotid ultrasonography is a laboratory procedure showing how arteriosclerosis screening can diagnose carotid artery occlusion and high-grade stenosis. It is useful for inspection in general practice because of its non-invasiveness, development of sonography equipment, laboratory methods and the establishment of an evaluation method. We generally use a linear array probe of around 7-8MHz for carotid observation and combine the B mode method, color and power Doppler method, and pulsed Doppler method for inspection. At vessel analysis, the intima-media thickness, the property of plaque and stenotic ratio are evaluated. We observe the direction of bloodstream and presence of stricture by Doppler color flow imaging and measure flow velocity and the wave pattern by pulsed Doppler method and, with the B mode method, evaluate the extent or degree of stricture. This can be depicted well using a convex array probe and sector array probe when the mental change caused by disease is deep, and depiction is difficult by linear array probe.

  17. P2 purinergic receptor activation of neuronal nitric oxide synthase and guanylyl cyclase in the dorsal facial area of the medulla increases blood flow in the common carotid arteries of cats.

    PubMed

    Hung, Y-W; Leung, Y-M; Lin, N-N; Lee, T J-F; Kuo, J-S; Tung, K-C; Gong, C-L

    2015-02-12

    In the dorsal facial area (DFA) of the medulla, an activation of either P2 purinergic receptor or nitric oxide synthase (NOS) results in the release of glutamate, leading to an increase in blood flow of the common carotid artery (CCA). It is not known whether activation of the P2 receptor by ATP may mediate activation of NOS/guanylyl cyclase to cause glutamate release and/or whether L-Arg (nitric oxide (NO) precursor) may also cause ATP release from any other neuron, to cause an increase in CCA flow. We demonstrated that microinjections of P2 receptor agonists (ATP, α,β-methylene ATP) or NO precursor (L-arginine) into the DFA increased CCA blood flow. The P2-induced CCA blood flow increase was dose-dependently reduced by pretreatment with NG-nitro-arginine methyl ester (L-NAME, a non-specific NOS inhibitor), 7-nitroindazole (7-NI, a relatively selective neuronal NOS inhibitor) or methylene blue (MB, a guanylyl cyclase inhibitor) but not by that with D-NAME (an isomer of L-NAME) or N5-(1-iminoethyl)-L-ornithine (L-NIO, a potent endothelial NOS inhibitor). Involvement of glutamate release in these responses were substantiated by microdialysis studies, in which perfusions of ATP into the DFA increased the glutamate concentration in dialysates, but co-perfusion of ATP with L-NAME or 7-NI did not. Nevertheless, the arginine-induced CCA blood flow increase was abolished by combined pretreatment of L-NAME and MB, but not affected by pretreatment with a selective P2 receptor antagonist, pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS). In conclusion, ATP activation of the P2 receptor in the DFA induced activation of neuronal NOS/guanylyl cyclase, which causes glutamate release leading to an increase in CCA blood flow. However, arginine activation of neuronal NOS/guanylyl cyclase, which also caused glutamate release and CCA blood flow increase, did not induce activation of P2 receptors. These findings provide important information for drug design and

  18. Glomus tissue in the vicinity of the human carotid sinus.

    PubMed Central

    Garfia, A

    1980-01-01

    Three of 60 cadavers have shown, in the adventitia or in the adipose tissue from the human carotid sinus region, small islands of tissue richly and typically vascularized and with nerve endings contacting cells like the tissue of the principal carotid body. In two of the cases such 'miniglomera' were single but in the third there were several all on the same side. A modified en bloc silver nitrate reduction stain was used to demonstrate the microvascular arrangements and the nerve endings by light microscopy of serial tangential sections of the carotid bifurcation. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 PMID:7364653

  19. Screening for Carotid Artery Stenosis

    MedlinePlus

    ... Task Force learned about the potential benefits and harms of screening for carotid artery stenosis: Health professionals ... blood flow through the arteries. Potential Benefits and Harms of Carotid Artery Stenosis Screening and Treatment The ...

  20. Idiopathic generalised tremor syndrome in two cats.

    PubMed

    Mauler, Daniela A; Van Soens, Iris; Bhatti, Sofie F; Cornelis, Ine; Martlé, Valentine A; Van Ham, Luc M

    2014-04-01

    Two male neutered domestic shorthair cats were evaluated for generalised tremors. On neurological examination both cats showed whole-body tremors, worsening with stress. A mainly cerebellar disorder was suspected. Blood examination, cerebrospinal fluid analysis and electrophysiological examination of both cats and magnetic resonance imaging of the brain in one cat were normal. Idiopathic generalised tremor syndrome (IGTS) was suspected owing to the exclusion of underlying causes and the clinical similarities with the syndrome in dogs. Treatment as recommended for dogs was initiated and resulted in improvement. This report describes the first cases of IGTS in cats.

  1. Genetic Polymorphisms in SOD (rs2070424, rs7880) and CAT (rs7943316, rs1001179) Enzymes Are Associated with Increased Body Fat Percentage and Visceral Fat in an Obese Population from Central Mexico.

    PubMed

    Hernández-Guerrero, César; Hernández-Chávez, Paulina; Romo-Palafox, Inés; Blanco-Melo, Grecia; Parra-Carriedo, Alicia; Pérez-Lizaur, Ana

    2016-07-01

    Oxidative disturbance is an important factor involved in the etiology of comorbidities associated with obesity. Genetic polymorphisms such as SOD1 -251A>G, SOD2 47 C>T, CAT -21A>T and CAT -262 C>T have been described to alter the activity of antioxidant enzymes. The aim of the present work was to analyze the association of the mentioned SNPs with obesity and their relationship with anthropometric and clinical variables in this group. The study included 416 Mexican women (208 normal weight, NW and 208 subjects with obesity, OB). Dietary intake, anthropometric, biochemical and clinical features were evaluated and then analyzed in function of the genotypes. The mutated carriers (GA+GG) of SOD -251 were significantly higher in the OB group (0.24) compared to the NW group (0.08). The other SNPs showed no differences compared with control group. When comparing carrier mutated subjects with obesity vs. wild-type obese participants with the SNPs SOD1 -251, SOD2 47 and CAT -262, the carriers showed a significantly (p <0.05) higher value in body fat percentage. Also, carriers of SOD2 47 and CAT-262 showed significantly higher values (p = 0.002) and (p = 0.01), respectively, when visceral fat was compared between groups. Systolic blood pressure was significantly higher (p = 0.02) in carriers of mutated CAT-21. SOD1 -251A>G is associated with obesity independent of the presence of diabetes or dyslipidemia. Mutated obese carries of SOD1 -251, SOD2 47 and CAT -262 are associated with a higher distribution of fat in comparison with obese wild-type carriers. Copyright © 2016 IMSS. Published by Elsevier Inc. All rights reserved.

  2. Cat scratch disease (image)

    MedlinePlus

    Cat scratch disease is an infectious illness associated with cat scratches, bites, or exposure to cat saliva, causing chronic swelling of the lymph nodes. Cat scratch disease is possibly the most common cause of chronic ...

  3. [Grafting of carotid arteries].

    PubMed

    Belov, Iu V; Stepanenko, A B; Gens, A P; Bazylev, V V; Seleznev, M N; Savichev, D D

    2005-01-01

    Over 5-years, 167 reconstructive surgeries for stenosis of internal carotid arteries (ICA) were performed in 124 patients. Mean age of the patients was 63.5 years. One hundred and twenty-nine carotid endarterectomies (CEAE) in 86 patients and 38 reconstructive operations of ICA in 38 patients were performed. There were no lethal outcomes in short- and long-term postoperative period. In short-term period after prosthesis of ICA restenosis was revealed in 3% patients, after eversion CEAE in 3% patients the embolism was seen, after standard CEAE restenosis were diagnosed in 8% patients and thrombosis -- in 3%. In long-term period after grafting of ICA the strokes were seen in 3%, stenosis -- in 6% patients, after eversion endarterectomy -- in 0 and 3% patients, and after standard CEAE -- in 3 and 24% patients, respectively. It is concluded that grafting of ICA is adequate surgical method of reconstruction and stroke prevention in specific variants of carotid atherosclerosis.

  4. Carotid surgery following previous carotid endarterectomy is safe and effective.

    PubMed

    Abou-Zamzam, Ahmed M; Moneta, Gregory L; Landry, Gregory J; Yeager, Richard A; Edwards, James M; McConnell, Donald B; Taylor, Lloyd M; Porter, John M

    2002-01-01

    With the perceived high risk of repeat carotid surgery, carotid angioplasty and stenting have been advocated recently as the preferred treatment of recurrent carotid disease following carotid endarterectomy. An experience with the operative treatment of recurrent carotid disease to document the risks and benefits of this procedure is presented. A review of a prospectively acquired vascular registry over a 10-year period (Jan. 1990-Jan. 2000) was undertaken to identify patients undergoing repeat carotid surgery following previous carotid endarterectomy. All patients were treated with repeat carotid endarterectomy, carotid interposition graft, or subclavian-carotid bypass. The perioperative stroke and death rate, operative complications, life-table freedom from stroke, and rates of recurrent stenosis were documented. During the study period 56 patients underwent repeat carotid surgery, comprising 6% of all carotid operations during this period. The indication for operation was symptomatic disease recurrence in 41 cases (73%) and asymptomatic recurrent stenosis >/=80% in 15 cases (27%). The average interval from the prior carotid endarterectomy to the repeat operation was 78 months (range 3 weeks-297 months). The operations performed included repeat carotid endarterectomy with patch angioplasty in 31 cases (55%), interposition grafts in 19 cases (34%), and subclavian-carotid bypass in 6 cases (11%). There were three perioperative strokes with one resulting in death for a perioperative stroke and death rate of 5.4%. One minor transient cranial nerve (CN IX) injury occurred. Mean follow-up was 29 months (range, 1-116 months). Life-table freedom from stroke was 95% at 1 year and 90% at 5 years. Recurrent stenosis (>/=80%) developed in three patients (5.4%) during follow-up, including one internal carotid artery occlusion. Two patients (3.6%) underwent repeat surgery. Repeat surgery for recurrent cerebrovascular disease following carotid endarterectomy is safe and

  5. Carotid Artery Screening

    MedlinePlus

    ... or radiologist then places the transducer on the skin in various locations, sweeping over the area of interest or angling the sound beam from a different location to better see an area of concern. Doppler sonography and Carotid IMT US are performed using the ...

  6. Carotid endarterectomy in patients with contralateral carotid artery occlusion.

    PubMed

    Dalainas, Ilias; Nano, Giovanni; Bianchi, Paolo; Casana, Renato; Malacrida, Giovanni; Tealdi, Domenico G

    2007-01-01

    The aim of this study was to evaluate the 30-day outcome of carotid endarterectomy in patients with contralateral carotid artery occlusion and compare it to that in patients with patent contralateral carotid artery. We compared 2,959 carotid endarterectomies performed in patients with patent contralateral internal carotid artery to 373 carotid endarterectomies performed in patients with occlusion of the contralateral carotid artery in the same institute between 1988 and 2004. Patient demographics, surgical and anesthesiological strategy, perioperative neurological and cardiac events, and deaths were compared. The patients were grouped and analyzed according to the presence or absence of symptoms and to their gender. No significant difference was shown in perioperative cardiological and neurological events and deaths in patients with contralateral carotid occlusion versus patients without contralateral carotid occlusion. Females had significant more neurological events than males, in both the asymptomatic (P < 0.001) and symptomatic (P = 0.02) groups. Concomitant occlusion of the contralateral carotid artery was not associated with increased risk of perioperative cardiological or neurological adverse events. However, female gender was associated with higher risk for adverse neurological events.

  7. Medial humeral epicondylitis in clinically affected cats.

    PubMed

    Streubel, Ronny; Bilzer, Thomas; Grest, Paula; Damur, Daniel; Montavon, Pierre M

    2015-10-01

    To describe the clinical signs and histologic changes in cats clinically affected with medial humeral epicondylitis (MHE) and evaluate long-term outcome after either conservative or surgical treatment. Prospective cohort study. Client-owned cats (n = 17) with MHE. Cats diagnosed with MHE, based on clinical signs, radiographs and computed tomography (CT), were prospectively recruited. Cats were treated conservatively for an initial 4 weeks, followed by either surgery or continued conservative treatment. Followup examinations were performed at 6 and 12 weeks and at 6-49 months. Cats had a mean age of 10.3 years and presented for chronic lameness. Examination revealed pain on palpation caudodistal to the medial epicondyle and by exerting antebrachial supination/pronation with elbow and carpal flexion. Lameness was restricted to 1 limb although CT revealed bilateral disease in 11/17 cats. Free mineralized joint bodies were identified in 9/17 cats. Nine cats were treated surgically and 8 cats were treated conservatively. Intraoperative findings included new bone formation at the origin of the humeral head of the flexor carpi ulnaris muscle with displacement and adhesions of the ulnar nerve. Microscopic examination revealed neurogenic myopathy in 4/9 cats treated surgically. Seven of 9 cats treated surgically were free from lameness by 12 weeks. Seven of 8 cats treated conservatively were chronically lame throughout the study. Cats with forelimb lameness should be evaluated for MHE. This condition is associated with free joint bodies and neurogenic myopathy. Surgical treatment is associated with excellent outcome in the majority of cats. © Copyright 2015 by The American College of Veterinary Surgeons.

  8. Management of carotid 'blowout' with endovascular stent grafts.

    PubMed

    Warren, Frank M; Cohen, James I; Nesbit, Gary M; Barnwell, Stanley L; Wax, Mark K; Andersen, Peter E

    2002-03-01

    Since 1992, endovascular techniques for vascular occlusion and stenting have evolved significantly. Endovascular occlusion of the carotid artery has been used in the management of carotid "blowout." Although it seems logical to expand this application to the use of arterial stents to repair rather than occlude the artery when cerebral cross-circulation is inadequate, concerns remain regarding the placement of a foreign body in a contaminated field. The purpose of the present report is to describe our experience with endovascular stents for control of carotid hemorrhage. Retrospective case review. Retrospective review of three cases of acute or threatened carotid hemorrhage managed with endovascular stent placement. Two patients presented with acute carotid blowout, and one patient with a probable sentinel bleed. All patients previously had been heavily treated with surgery and irradiation: Two had developed pharyngocutaneous fistulas, and one had an open wound filled with tumor that surrounded the carotid artery. All were thought to be at significant risk for stroke if the carotid artery was occluded. In all three patients, stent placement resolved the acute hemorrhage. Mean duration of follow-up was 8.3 months. In two patients, the stent became exposed, ultimately thrombosed or extruded, or both. The third patient had no residual sequelae of stenting but died 3 months later. When an unacceptable risk of cardiovascular accident makes occlusion unwise, acute carotid hemorrhage can be successfully managed with directed placement of endovascular stents, but the long-term sequelae of placing these foreign bodies in a field with ongoing contamination make this a temporizing rather than permanent measure for use while more definitive long-term solutions are pursued.

  9. Cat scratch disease.

    PubMed

    Bozhkov, V; Madjov, R; Plachkov, I; Arnaudov, P; Chernopolsky, P; Krasnaliev, I

    2014-01-01

    Approximately 24,000 people are infected with cat scratch disease (CSD) every year. CSD is caused by the bacteria Bartonella henselae, a gram-negative bacteria most often transmitted to humans through a bite or scratch from an infected cat or kitten. Although CSD is often a benign and self-limiting condition, it can affect any major organ system in the body, manifesting in different ways and sometimes leading to lifelong sequelae. It is a disease that is often overlooked in primary care because of the wide range of symptom presentation and relative rarity of serious complications. It is important for health care providers to recognize patients at risk for CSD, know what laboratory testing and treatments are available, and be aware of complications that may arise from this disease in the future.

  10. Carotid-cardiac baroreflex influence on forearm vascular resistance during low level LBNP

    NASA Technical Reports Server (NTRS)

    Ludwig, David

    1990-01-01

    Twelve healthy males were tested at low levels of lower body negative pressure (LBNP) with and without artificial stimulation of the carotid-cardiac baroreceptors. The carotid-cardiac baroreceptors were stimulated by applying a pressure of 10 mmHg to the carotid artery via a pressurized neck chamber. During the procedure, forearm blood flow (FBF) and forearm vascular resistance (FVR) were measured using a Whitney mercury silastic strain gauge technique. FBF decreased while FVR increased with increased intensity of LBNP. Both FBF and FVR were unaffected by carotid-cardiac baroreceptor stimulation.

  11. Management of Carotid Artery Trauma

    PubMed Central

    Lee, Thomas S.; Ducic, Yadranko; Gordin, Eli; Stroman, David

    2014-01-01

    With increased awareness and liberal screening of trauma patients with identified risk factors, recent case series demonstrate improved early diagnosis of carotid artery trauma before they become problematio. There remains a need for unified screening criteria for both intracranial and extracranial carotid trauma. In the absence of contraindications, antithrombotic agents should be considered in blunt carotid artery injuries, as there is a significant risk of progression of vessel injury with observation alone. Despite CTA being used as a common screening modality, it appears to lack sufficient sensitivity. DSA remains to be the gold standard in screening. Endovascular techniques are becoming more widely accepted as the primary surgical modality in the treatment of blunt extracranial carotid injuries and penetrating/blunt intracranial carotid lessions. Nonetheless, open surgical approaches are still needed for the treatment of penetrating extracranial carotid injuries and in patients with unfavorable lesions for endovascular intervention. PMID:25136406

  12. Obesity and carotid artery remodeling

    PubMed Central

    Kozakova, M; Palombo, C; Morizzo, C; Højlund, K; Hatunic, M; Balkau, B; Nilsson, P M; Ferrannini, E

    2015-01-01

    Background/Objective: The present study tested the hypothesis that obesity-related changes in carotid intima-media thickness (IMT) might represent not only preclinical atherosclerosis but an adaptive remodeling meant to preserve circumferential wall stress (CWS) in altered hemodynamic conditions characterized by body size-dependent increase in stroke volume (SV) and blood pressure (BP). Subjects/Methods: Common carotid artery (CCA) luminal diameter (LD), IMT and CWS were measured in three different populations in order to study: (A) cross-sectional associations between SV, BP, anthropometric parameters and CCA LD (266 healthy subjects with wide range of body weight (24–159 kg)); (B) longitudinal associations between CCA LD and 3-year IMT progression rate (ΔIMT; 571 healthy non-obese subjects without increased cardiovascular (CV) risk); (C) the impact of obesity on CCA geometry and CWS (88 obese subjects without CV complications and 88 non-obese subjects matched for gender and age). Results: CCA LD was independently associated with SV that was determined by body size. In the longitudinal study, baseline LD was an independent determinant of ΔIMT, and ΔIMT of subjects in the highest LD quartile was significantly higher (28±3 μm) as compared with those in the lower quartiles (8±3, 16±4 and 16±3 μm, P=0.001, P<0.05 and P=0.01, respectively). In addition, CCA CWS decreased during the observational period in the highest LD quartile (from 54.2±8.6 to 51.6±7.4 kPa, P<0.0001). As compared with gender- and age-matched lean individuals, obese subjects had highly increased CCA LD and BP (P<0.0001 for both), but only slightly higher CWS (P=0.05) due to a significant increase in IMT (P=0.005 after adjustment for confounders). Conclusions: Our findings suggest that in obese subjects, the CCA wall thickens to compensate the luminal enlargement caused by body size-induced increase in SV, and therefore, to normalize the wall stress. CCA diameter in obesity could

  13. How Is Carotid Artery Disease Treated?

    MedlinePlus

    ... from the NHLBI on Twitter. How Is Carotid Artery Disease Treated? Treatments for carotid artery disease may ... plaque removed and normal blood flow restored. Carotid Artery Angioplasty and Stenting Doctors use a procedure called ...

  14. How Can Carotid Artery Disease Be Prevented?

    MedlinePlus

    ... from the NHLBI on Twitter. How Can Carotid Artery Disease Be Prevented? Taking action to control your risk factors can help prevent or delay carotid artery disease and stroke . Your risk for carotid artery ...

  15. Cool Cats: Feline Fun with Abstract Art.

    ERIC Educational Resources Information Center

    Lambert, Phyllis Gilchrist

    2002-01-01

    Presents a lesson that teaches students about abstract art in a fun way. Explains that students draw cats, learn about the work of Pablo Picasso, and, in the style of Picasso, combine the parts of the cats (tail, legs, head, body) together in unconventional ways. (CMK)

  16. Cool Cats: Feline Fun with Abstract Art.

    ERIC Educational Resources Information Center

    Lambert, Phyllis Gilchrist

    2002-01-01

    Presents a lesson that teaches students about abstract art in a fun way. Explains that students draw cats, learn about the work of Pablo Picasso, and, in the style of Picasso, combine the parts of the cats (tail, legs, head, body) together in unconventional ways. (CMK)

  17. An 8-channel RF coil array for carotid artery MR imaging in humans at 3 T.

    PubMed

    Hu, Xiaoqing; Zhang, Lei; Zhang, Xiaoliang; Zhu, Huabin; Chen, Xiao; Zhang, Yongqin; Chung, Yiu-Cho; Liu, Xin; Zheng, Hairong; Li, Ye

    2016-04-01

    Carotid artery diseases due to plaque buildup at the carotid bifurcation are a leading cause of stroke. Accurate plaque quantification and characterization of plaque composition and morphology by magnetic resonance imaging (MRI) is essential to identifying high-risk patients. Difficulties in detecting plaque, which is physically small, and the unique physiological structure of the carotid artery make use of a radio frequency (RF) coil array with high resolution, large longitudinal coverage, and deep penetration ideal for clinical examinations. The goal of this project was to design and fabricate a sensitive RF coil array with sufficient imaging coverage and signal-to-noise ratio (SNR) for carotid artery imaging at 3 T. Based on clinical requirements and the anatomical structure of the human carotid artery, an 8-channel carotid coil array was designed and fabricated for 3 T MRI of the carotid artery in humans. The performance of the proposed 8-channel carotid coil array was validated through bench tests and MR imaging experiments on a 3 T whole body MRI scanner. Its performance was also compared experimentally to the performance of a commercial 4-channel phased array carotid coil designed by Machnet BV (Machnet BV coil, Roden, Netherlands). The 8-channel carotid coil array performed significantly better in imaging the carotid artery than the commercial 4-channel Machnet BV coil in terms of the SNR, coverage, and penetration depth. In parallel imaging, the proposed 8-channel carotid coil array demonstrated a much lower maximum value and average value of the geometry factor in the region of interest. Carotid artery images acquired in vivo using the proposed 8-channel carotid artery coil and the commercial 4-channel Machnet BV coil were also compared, demonstrating the former's potential for clinical diagnosis. Based on the analyses of phantom and in vivo imaging studies, the proposed 8-channel carotid coil array has the potential for use in clinical diagnosis

  18. Atherosclerosis measured by whole body magnetic resonance angiography and carotid artery ultrasound is related to arterial compliance, but not to endothelium-dependent vasodilation - the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study.

    PubMed

    Lind, Lars; Andersson, Jessika; Hansen, Tomas; Johansson, Lars; Ahlström, Håkan

    2009-09-01

    Arterial compliance and endothelium-dependent vasodilation are two characteristics of the vessel wall. In the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, we studied the relationships between arterial compliance and endothelium-dependent vasodilation versus atherosclerosis as measured with two imaging modalities. In the population-based PIVUS study (1016 subjects aged 70), arterial compliance was determined by ultrasound in the carotid artery and the stroke volume to pulse pressure ratio by echocardiography, while endothelium-dependent vasodilation was assessed by the invasive forearm technique with acetylcholine and brachial artery ultrasound. Intima-media thickness was evaluated by ultrasound in the carotid artery (n = 954). Stenosis in the carotid, aorta, renal, upper and lower leg arteries were determined by magnetic resonance angiography in a random subsample of 306 subjects. After adjustments for gender, Framingham risk score, obesity, myocardial infarction and stroke, distensibility in the carotid artery and the stroke volume to pulse pressure ratio were both significantly related to a weighted index of stenosis in the five arterial territories evaluated by magnetic resonance angiography (p<0.02 for both). Distensibility in the carotid artery (P = 0.021), but not the stroke volume to pulse pressure ratio (P = 0.08), was also significantly related to intima-media thickness. In the elderly population, atherosclerosis is mainly related to arterial compliance, but not to endothelium-dependent vasodilation in peripheral conduit or resistance vessels.

  19. Cat scratch disease

    MedlinePlus

    ... t scratch and bite. Don't allow a cat to lick your skin, eyes, mouth, or open wounds or scratches. Use flea control measures to lower the risk your cat develops the disease. Don't touch feral cats. ...

  20. Endovascular treatment of the carotid stump syndrome.

    PubMed

    Nano, Giovanni; Dalainas, Ilias; Casana, Renato; Malacrida, Giovanni; Tealdi, Domenico G

    2006-01-01

    In patients with an occluded internal carotid artery, the carotid stump syndrome is a potential source of microemboli that pass through the ipsilateral external carotid artery and the ophthalmic artery to the territory of the middle cerebral artery. Thus, the syndrome is associated with carotid territory symptoms although the internal carotid artery is occluded. Surgical exclusion of the internal carotid artery associated with endarterectomy of the external carotid artery has been described as the gold standard of treatment by many authors. This report is the second case, to our knowledge, of endovascular treatment of the carotid stump syndrome with the use of a stent-graft.

  1. Carotid Artery Stenting versus Endarterectomy

    PubMed Central

    Gahremanpour, Amir; Perin, Emerson C.; Silva, Guilherme

    2012-01-01

    For about 2 decades, investigators have been comparing carotid endarterectomy with carotid artery stenting in regard to their effectiveness and safety in treating carotid artery stenosis. We conducted a systematic review to summarize and appraise the available evidence provided by randomized trials, meta-analyses, and registries comparing the clinical outcomes of the 2 procedures. We searched the MEDLINE, SciVerse Scopus, and Cochrane databases and the bibliographies of pertinent textbooks and articles to identify these studies. The results of clinical trials and, consequently, the meta-analyses of those trials produced conflicting results regarding the comparative effectiveness and safety of carotid endarterectomy and carotid stenting. These conflicting results arose because of differences in patient population, trial design, outcome measures, and variability among centers in the endovascular devices used and in operator skills. Careful appraisal of the trials and meta-analyses, particularly the most recent and largest National Institutes of Healthsponsored trial (the Carotid Revascularization Endarterectomy vs Stenting Trial [CREST]), showed that carotid stenting and endarterectomy were associated with similar rates of death and disabling stroke. Within the 30-day periprocedural period, carotid stenting was associated with higher risks of stroke, especially for patients aged >70 years, whereas carotid endarterectomy was associated with a higher risk of myocardial infarction. The slightly higher cost of stenting compared with endarterectomy was within an acceptable range by cost-effectiveness standards. We conclude that carotid artery stenting is an equivalent alternative to carotid endarterectomy when patient age and anatomy, surgical risk, and operator experience are considered in the choice of treatment approach. PMID:22949763

  2. [Carotid duplex ultrasonography for neurosurgeons].

    PubMed

    Sadahiro, Hirokazu; Ishihara, Hideyuki; Oka, Fumiaki; Suzuki, Michiyasu

    2011-12-01

    Carotid duplex ultrasonography (CDU) is one of the most well-known imaging methods for arteriosclerosis and ischemic stroke. For neurosurgeons, it is very important for the details of carotid plaque to be thoroughly investigated by CDU. Symptomatic carotid plaque is very fragile and easily changes morphologically, and so requires frequent CDU examination. Furthermore, after carotid endarterectomy (CEA) and carotid artery stenting (CAS), restenosis is evaluated with CDU. CDU facilitates not only morphological imaging in the B mode, but also allows a flow study with color Doppler and duplex imaging. So, CDU can help assess the presence of proximal and intracranial artery lesions in spite of only having a cervical view, and the patency of the extracranial artery to intracranial artery bypass is revealed with CDU, which shows a rich velocity and low pulsatility index (PI) in duplex imaging. For the examiner, it is necessary to ponder on what duplex imaging means in examinations, and to summarize all imaging finding.

  3. Clinical results of carotid artery stenting versus carotid endarterectomy

    PubMed Central

    Akinci, Tuba; Derle, Eda; Kibaroğlu, Seda; Harman, Ali; Kural, Feride; Cınar, Pınar; Kilinc, Munire; Akay, Hakki T.; Can, Ufuk; Benli, Ulku S.

    2016-01-01

    Objective: To review our results of carotid artery stenting (CAS) and carotid endarterectomy (CEA). Methods: We evaluated the medical records of patients undergoing carotid artery revascularization procedure, between 2001 and 2013 in Baskent University Hospital, Ankara, Turkey. Carotid artery stenting or CEA procedures were performed in patients with asymptomatic carotid stenosis (≥70%) or symptomatic stenosis (≥50%). Demographic data, procedural details, and clinical outcomes were recorded. Primary outcome measures were in 30-day stroke/transient ischemic attacks (TIA)/amaurosis fugax or death. Secondary outcome measures were nerve injury, bleeding complications, length of stay in hospital, stroke, restenosis (ICA patency), and all-cause death during long-term follow-up. Results: One hundred ninety-four CEA and 115 CAS procedures were performed for symptomatic and/or asymptomatic carotid artery stenosis. There is no significant differences 30-day mortality and neurologic morbidity between CAS (13%) and CEA procedures (7.7%). Length of stay in hospital were significantly longer in CEA group (p=0.001). In the post-procedural follow up, only in symptomatic patients, restenosis rate was higher in the CEA group (p=.045). The other endpoints did not differ significantly. Conclusions: Endovascular stent treatment of carotid artery atherosclerotic disease is an alternative for vascular surgery, especially for patients that are high risk for standard CEA. The increasing experience, development of cerebral protection systems and new treatment protocols increases CAS feasibility. PMID:27744460

  4. Redistribution by 5-hydroxytryptamine of carotid arterial blood at the expense of arteriovenous anastomotic blood flow

    PubMed Central

    Saxena, Pramod R.; Verdouw, Pieter D.

    1982-01-01

    1. The effects of 5-hydroxytryptamine by intravenous (1, 5 and 10 μg kg-1 min-1 in cats) and intracarotid (0·5 and 2 μg kg-1 min-1 in pigs) routes were studied on the complete distribution of common carotid artery blood flow, measured with radioactive microspheres (15 μm). In addition, the amine was also infused (0·75-3 μg kg-1 min-1) into the carotid artery of cats to observe its influence on the shunting of microspheres in the jugular venous blood. 2. The basal total common carotid blood flow was distributed ipsilaterally mainly to extracerebral tissues and only little blood entered the brain. As shown by the presence of microspheres in the lungs after injection into the carotid artery (52% in cats; 82% in pigs), a major fraction of the carotid blood by-passed the capillary bed through arteriovenous anastomoses in the head (non-nutrient fraction). 3. 5-Hydroxytryptamine redistributed the blood in favour of the nutrient compartment at the expense of arteriovenous anastomotic fraction. In cats, tissue blood flow did not significantly change but, in the pig, blood flow to all tissues, particularly to skin and ears, was substantially increased despite a reduction in total carotid blood flow. This reduction was entirely due to a change in the non-nutrient fraction. 4. Intracarotid infusion of 5-hydroxytryptamine in vagosympathectomized intact or spinal cats decreased the number of microspheres appearing in the jugular venous blood, again indicating a reduction in arteriovenous anastomotic flow due to a constriction of these non-nutrient vessels. 5. Cyproheptadine (1 mg kg-1) completely reversed the effect of 5-hydroxytryptamine on the total carotid blood flow. However, the vasoconstriction of arteriovenous anastomoses was only partially attenuated and the vasodilatatory response was either unchanged (muscle) or even enhanced (skin, ear and bones). 6. It is suggested that 5-hydroxytryptamine causes vasoconstriction of the large arteries via D-receptors which are

  5. Percutaneous Thrombin Injection with a Distal Embolic Protection Device for Treatment of a Common Carotid Artery Pseudoaneurysm

    PubMed Central

    Lee, J.H.; Tseng, I.K.; Siegel, R.L.; Roychowdhury, S.

    2013-01-01

    Summary Carotid artery pseudoaneurysm is a rare complication from placement of an internal jugular triple lumen catheter. Endovascular stenting is the favored treatment option in the setting of traumatic carotid injury. In other parts of the body, specifically the femoral artery, thrombin injection has become the standard of care. We intend to show that effective management of carotid pseudoaneurysms can also be achieved with thrombin injection after placement of a distal embolic protection device. PMID:23693049

  6. Carotid Disease Management: Surgery, Stenting, or Medication.

    PubMed

    Khandelwal, Priyank; Chaturvedi, Seemant

    2015-09-01

    Internal carotid artery stenosis accounts for about 7-10 % of ischemic strokes. Conventional risk factors such as aging, hypertension, diabetes mellitus, and smoking increase the risk for carotid atherosclerosis. All patients with carotid stenosis should receive aggressive medical therapy. Carotid revascularization with either endarterectomy or stenting can benefit select patients with severe stenosis. New clinical trials will examine the contemporary role of carotid revascularization relative to optimal medical therapy.

  7. [Carotid endarterectomy under local anesthesia].

    PubMed

    Kuz'min, A L; Belov, Iu V

    2001-01-01

    Results of carotid endarterectomy (CEAE) in 193 patients with different degree of cerebrovascular insufficiency were analyzed. All the patients were men with carotid atherosclerosis (age from 39 to 68 years, mean age 53.6 +/- 0.4). A total of 253 CEAEs were performed under local anesthesia (60 patients underwent consecutive bilateral operations). In early postoperative period 3 patients died, one of them--of ischemic stroke due to thrombosis of internal carotid artery on the side of the operation. Non-fatal stroke was in 1 patient. There were no intraoperative cerebral complications. This testifies to reliability of cerebral circulation control through direct contact with patient.

  8. Use of absorbable sutures in canine carotid arteries.

    PubMed

    Rey, A R; Carrillo-Farga, J; Velasco, C O; Valencia, M O

    1990-01-01

    To study the functional and microstructural characteristics of polydioxanone sutures in vascular surgery, we created 48 vascular anastomoses in the right and left common carotid arteries of 24 mongrel dogs. In each animal, polydioxanone sutures were used in 1 carotid artery, and polypropylene sutures were used in the contralateral carotid artery. Twelve groups of 2 animals each were then formed. The 1st group was observed for 1 month, the 2nd for 2 months, the 3rd for 3 months, and so on until the 12th group, which was observed for 12 months. At the end of each observation period, reoperation was undertaken to evaluate the vascular anastomoses by means of angiography and microscopy. The polypropylene anastomoses showed a marked deformity, with tissue retraction and a foreign body reaction. In contrast, the polydioxanone anastomoses exhibited satisfactory healing, without deformity, and were well tolerated histologically. We believe that polydioxanone may be a useful, alternative vascular suture material.

  9. [Extreme neutrophilia in cats - aetiology and prognosis].

    PubMed

    Langenstein, J; Bauer, N; Moritz, A

    2015-01-01

    The aim of this retrospective study was to evaluate the aetiology and prognostic factors of extreme neutrophilia in cats. Patient data over a 5-year period (January 2008  -  December 2013) were reviewed. Cats with a neutrophil count > 40 x 10⁹/l were included. They were further assigned to four groups: "inflammation", "neoplasia", "immune-mediated diseases", "unknown aetiology". Clinical signs, rectal temperature, hospitalisation, duration of hospitalisation, survival, left-shift and toxicity of neutrophils were evaluated. In total, 28/5185 cats (0.5%) displayed extreme neutrophilia with a mean neutrophil count of 48.5 x 10⁹/l (40.0-76.0 x 10⁹/l). The most common aetiology was a severe inflammation, as seen in 16/28 cats (57%), whereby peritonitis (5/15 cats, 31%) predominated. In cats with neoplastic diseases (9/28 cats, 32%), intestinal neoplasia with subsequent peritonitis was the most common diagnosis (4/9 cats, 44%). Diseases of unknown aetiology (2/28 cats, 7%) and immune-mediated diseases (1/28, 3.6%) were rare. The most common clinical indications included lethargy, anorexia, fever, and gastrointestinal signs. Rectal temperature ranged between 33.9  °C and 40.2   °C, whereby in 2/24 cats (8%) hyperthermia (> 39.3°C) and in 5/24 cats (21%) hypothermia (< 38.0°C) was observed. Hospitalisation occurred in 21/28 cats (75%) with a median duration of 5.5 days (1-30 days). In 24/28 cats, a manual differential count was performed. A left-shift and toxicity of neutrophils were seen in 23/24 cats (96%) and 21/24 cats (88%), respectively. The overall median survival rate was 50%, whereby the survival rate was significantly lower in cats with neoplasia than in those with inflammatory diseases (22% vs. 56%, p < 0.0001). An extreme neutrophilia is rare. It is commonly caused by peritonitis due to foreign bodies or ruptured intestinal tumours (in particular, intestinal lymphomas) and is characterised by a high mortality.

  10. [Cerebral hemorrhage after carotid endarterectomy in a young adult].

    PubMed

    Parra, J; Sancho, J; Santonja, J M; Pareja, A; Peiró, C

    1997-02-01

    Cerebral haemorrhage after carotid endarterectomy is a rare complication. It follows 0.5% to 20% of all endarterectomies, but should be borne in mind because of the morbidity and mortality seen in most cases. We describe the case of a 42 year old man in whom carotid endarterectomy had been done 7 days before to treat a stenosis of 80%. He complained of a sudden onset of weakness of the right half of his body and changes in his speech. Physical examination showed right inferior facial paresia, right hemiparesia and right extensor cutaneous plantar reflex. On admission to the Emergency Department, before treatment, blood pressure was 80/60. Carotid auscultation and palpation were normal. Cerebral TRC showed a left lenticular haematoma. The patient progressed satisfactorily. We review the literature on the subject as well as the factors which should be considered as possibly predisposing to bleeding after carotid endarterectomy, such as arterial hypertension and occlusion or severe stenosis of the contralateral carotid artery. The detection of patients with the risk of postendarterectomy bleeding by simple noninvasive investigations, such as the transcranial doppler and the acetazolamide test, and early diagnosis of a clinical picture compatible with a hyperperfusion syndrome may contribute to the relief and prevention of sequelae in these patients.

  11. ATP- and ACh-induced responses in isolated cat petrosal ganglion neurons.

    PubMed

    Alcayaga, Carmen; Varas, Rodrigo; Valdés, Viviana; Cerpa, Verónica; Arroyo, Jorge; Iturriaga, Rodrigo; Alcayaga, Julio

    2007-02-02

    Chemoreceptor (glomus) cells of the carotid body are synaptically connected to the sensory nerve endings of petrosal ganglion (PG) neurons. In response to natural stimuli, the glomus cells release transmitters, which acting on the nerve terminals of petrosal neurons increases the chemosensory afferent discharge. Among several transmitter molecules present in glomus cells, acetylcholine (ACh) and adenosine 5'-triphosphate (ATP) are considered to act as excitatory transmitter in this synapse. To test if ACh and ATP play a role as excitatory transmitters in the cat CB, we recorded the electrophysiological responses from PG neurons cultured in vitro. Under voltage clamp, ATP induces a concentration-dependent inward current that partially desensitizes during 20-30 s application pulses. The ATP-induced current has a threshold near 100 nM and saturates between 20-50 muM. ACh induces a fast, inactivating inward current, with a threshold between 10-50 muM, and saturates around 1 mM. A large part of the population of PG neurons (60%) respond to both ATP and ACh. Present results support the hypothesis that ACh and ATP act as excitatory transmitters between cat glomus cells and PG neurons.

  12. Rubbings deposited by cats elicit defensive behavior in rats.

    PubMed

    May, Matthew D; Bowen, Michael T; McGregor, Iain S; Timberlake, William

    2012-12-05

    Laboratory rats display pronounced defensive behaviors when confronted with a range of cat-derived stimuli, including collars worn by a cat, cloths rubbed on a cat, and cat fur. One possible explanation of this phenomenon (the "kairomone hypothesis") is that rats derive a survival advantage by eavesdropping on signals used by cats to communicate with each other. Cats are known to rub their bodies on objects at strategic environmental locations to signal their identity and mating potential to other cats. The current study assessed the sensitivity of laboratory rats to these body rubbings. In Experiment 1, food deprived Sprague-Dawley rats were trained to consume food pellets in one arm of a Y maze. On test day a damp cloth was placed near the food pellets that had been rubbed on a location (wall) where a cat had recently engaged in body rubbing. A control cloth and a collar worn by the cat were also tested. The presence of both the body rubbing residue and the cat collar increased latency to eat and decreased amount of food eaten. The disruption of consummatory behavior in the test environment was still evident 24h later in the absence of odor stimuli. Experiment 2 tested the reaction of naïve Wistar rats to body rubbings using a paradigm in which rats were given the opportunity to hide. Relative to a control condition, rats exposed to a cotton pad wiped on a cat body rubbing location showed increased hiding behavior, decreased exploration and reduced stimulus approach and investigation. These defensive responses persisted for up to 4days following a single stimulus exposure. These results suggest that rats eavesdrop readily on body rubbings cats use for identification purposes, providing further support for a kairomone hypothesis of predator odor avoidance. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Assessment of arterial compliance by carotid midwall strain-stress relation in normotensive adults.

    PubMed

    Bella, J N; Roman, M J; Pini, R; Schwartz, J E; Pickering, T G; Devereux, R B

    1999-03-01

    Examining left ventricular midwall as opposed to endocardial mechanics enhances understanding of left ventricular function in individuals with abnormal cardiac geometry. Accordingly, we used carotid ultrasound and applanation tonometry of arterial pressure to derive carotid midwall strain and its relation to carotid peak-systolic and end-diastolic stresses in 82 apparently normal, employed subjects (56 men, 26 women; median age, 47 years; 70% white; 21% overweight) with no evidence of coronary or valvular heart disease. Regression equations relating carotid luminal and midwall strain to the increment in carotid stress during systole (Deltacarotid stress) were used to predict strain for the observed Deltastress. Observed/predicted carotid luminal or midwall strain was calculated as a measure of carotid luminal or midwall strain for imposed stress, termed stress-corrected strain. Midwall carotid strain was similar in women and men but was negatively related to older age (r=-0.35, P=0.001) and higher body mass index (r=-0.31, P=0.005) and brachial and carotid blood pressure (r=-0.30 to -0.45, all P<0.01). The pulsatile change in arterial load, measured by Deltacarotid stress, was positively related to midwall strain (r=0. 44, P<0.001) more closely than was carotid luminal strain. Regression analyses revealed that carotid midwall strain was positively related to Deltastress, with additional negative relations to age and carotid diastolic diameter (all P<0.001). Stress-corrected carotid midwall strain was strongly and negatively correlated with midwall elastic modulus and Young's modulus (both r=-0.77, P<0.001), followed by elastic modulus (r=-0.74, P<0.001), midwall Young's modulus (r=-0.73, P<0.001), midwall stiffness index (r=-0.70, P<0.001), and stiffness index (r=-0.66, P<0.001). Thus, in normal adults, carotid midwall strain is unrelated to gender, is positively related to pulsatile carotid load as measured by Deltacarotid stress, and is negatively related to age

  14. pH regulation in adult rat carotid body glomus cells. Importance of extracellular pH, sodium, and potassium [published erratum appears in J Gen Physiol 1993 Jan;101(1):following 144

    PubMed Central

    1992-01-01

    The course of intracellular pH (pHi) was followed in superfused (36 degrees C) single glomus (type I) cells of the freshly dissociated adult rat carotid body. The cells had been loaded with the pH-sensitive fluorescent dye 2',7'-(2-carboxyethyl)-5 (and -6)-carboxyfluorescein. The high K(+)-nigericin method was used for calibration. The pHi of the glomus cell at pHo 7.40, without CO2, was 7.23 +/- 0.02 (n = 70); in 5% CO2/25 mM HCO3-, pHi was 7.18 +/- 0.08 (n = 9). The pHi was very sensitive to changes in pHo. Without CO2, delta pHi/delta pHo was 0.85 (pHo 6.20-8.00; 32 cells), while in CO2/HCO3- this ratio was 0.82 irrespective of whether pHo (6.80-7.40; 14 cells) was changed at constant PCO2 or at constant [HCO3-]o. The great pHi sensitivity of the glomus cell to pHo is matched only by that of the human red cell. An active Na+/H+ exchanger (apparent Km = 58 +/- 6 mM) is present in glomus cells: Na+ removal or addition of the amiloride derivative 5- (N,N-hexamethylene)-amiloride induced pHi to fall by as much as 0.9. The membrane of these cells also contains a K+/H+ exchanger. Raising [K+]o from 4.7 to 25, 50, or 140 mM reversibly raised pHi by 0.2, 0.3, and 0.6, respectively. Rb+ had no effect, but in corresponding concentrations of Tl+ alkalinization was much faster than in K+. Reducing [K+]o to 1.5 mM lowered pHi by 0.1. These pHi changes were shown not to be due to changes in membrane voltage, and were even more striking in the absence of Na+. Intrinsic buffering power (amount of strong base required to produce, in the nominal absence of CO2, a small pHi rise) increased from 3 to approximately 21 mM as pHi was lowered, but remained nearly unchanged below pHi 6.60. The fitted expression assumed the presence of one "equivalent" intracellular buffer (pK 6.41, 41 mM). The exceptional pHi sensitivity to pHo suggests that the pHi of the glomus cell is a link in the chemoreceptor's response to external acidity. PMID:1294152

  15. Cat-Scratch Disease

    MedlinePlus

    ... Spanish Announcements Connect With Us Digital Press Kit Cat-Scratch Disease Recommend on Facebook Tweet Share Compartir ( ... play and learn how to attack prey. How cats and people become infected Kitten playing with a ...

  16. Cat Scratch Disease

    MedlinePlus

    Cat scratch disease (CSD) is an illness caused by the bacterium Bartonella henselae. Almost half of all cats carry the infection ... symptoms of CSD, call your doctor. Centers for Disease Control and Prevention

  17. [Primary hyperaldosteronism in cats].

    PubMed

    Willi, B; Kook, P H; Quante, S; Boretti, F; Sieber-Ruckstuhl, N S; Grest, P; Scherrer, O; Riond, B; Hofmann-Lehmann, R; Nussberger, J; Reusch, C E

    2012-12-01

    Primary hyperaldosteronism is a clinical syndrome characterized by an elevated aldosterone secretion by the adrenals. The present case series describes 7 cats with primary hyperaldosteronism, which were presented between 2002 and 2011. Common clinical symptoms were weakness, anorexia, cervical ventroflexion and blindness. All cats showed hypokalemia. In 6 cats, blood pressure was determined: 5 cats showed hypertension, of which 4 animals exhibited retinal detachment and blindness. In the ultrasonographic examination, unilateral adrenomegaly was present in 6 cats whereas one animal showed normal adrenals. In 4 cats, the serum aldosterone concentration was above the reference range. Five cats underwent unilateral adrenalectomy, which was accomplished uneventfully and returned the electrolytes back to normal. Histopathological examination of the adrenals revealed 2 carcinomas and 4 adenomas; one cat with ultrasonographic normal adrenals exhibited bilateral nodular hyperplasia.

  18. The validity of internal carotid back pressure measurements during carotid endarterectomy for unilateral carotid stenosis.

    PubMed

    Lord, R S; Graham, A R

    1986-06-01

    Peri-operative neurological deficits in 212 patients undergoing carotid endarterectomy for unilateral carotid stenosis were examined to determine whether the internal carotid back pressure (ICBP) correctly predicted the need for a protective shunt during temporary carotid occlusion. Three strokes occurred in 149 patients who were not shunted. In one of these the ICBP indicated the need for a shunt, but shunting was not possible for technical reasons and a stroke due to hypoperfusion occurred. In another patient a stroke occurred as a result of embolism. There was only one patient where the ICBP possibly incorrectly predicted that a shunt would not be necessary. Four strokes due to various causes occurred in the 63 shunted patients. Shunting was not withheld from these patients in order to prove that ICBP would correctly predict their vulnerability to hypoperfusion since to have done so would be unethical. The results indicate that in patients with unilateral carotid stenosis the ICBP is an accurate indicator of which patients can undergo carotid endarterectomy without the need for shunting.

  19. Ototoxicity in dogs and cats.

    PubMed

    Oishi, Naoki; Talaska, Andra E; Schacht, Jochen

    2012-11-01

    A variety of drugs in veterinary use have side effects that can potentially damage the senses of hearing or balance in animals. A large body of literature exists on the incidence and mechanisms of ototoxicity in experimental animals and in humans, but little is documented in domestic dogs and cats. However, the generality of these adverse actions across species allows one to extrapolate and provide the veterinarian with insight into possible complications of chemotherapy.

  20. Ototoxicity in dogs and cats

    PubMed Central

    Oishi, Naoki; Talaska, Andra E.; Schacht, Jochen

    2012-01-01

    Synopsis A variety of drugs in veterinary use have side effects that can potentially damage the senses of hearing or balance in animals. A large body of literature exists on the incidence and mechanisms of “ototoxicity” in experimental animals and in humans, but little is documented in domestic dogs and cats. However, the generality of these adverse actions across species allows us to extrapolate and provide the veterinarian with insight into possible complications of chemotherapy. PMID:23122180

  1. CATS Featured Articles

    Atmospheric Science Data Center

    2017-01-31

      CATS Featured Articles       A Slice of Cirrus: Image of ... just hours before by the Cloud-Aerosol Transport System (CATS) onboard the International Space Station. Nighttime View of Raung Volcanic Plume : Natural Hazards  - The CATS instrument slices through darkness to reveal the vertical structure of a ...

  2. Cardiomyopathy prevalence in 780 apparently healthy cats in rehoming centres (the CatScan study).

    PubMed

    Payne, Jessie Rose; Brodbelt, David Charles; Luis Fuentes, Virginia

    2015-12-01

    Hypertrophic cardiomyopathy (HCM) appears to be common in cats and, based on pilot data, a prevalence of 15% has been hypothesized. The objectives were to screen a large population of apparently healthy adult cats for cardiac disease, and identify factors associated with a diagnosis of HCM. A total of 1007 apparently healthy cats ≥ 6 months of age. In this prospective, cross-sectional study, the inclusion criteria were: apparently healthy cats, aged ≥ 6 months, available for rehoming over a 17-month period from two rehoming centres. Hypertensive or hyperthyroid cats were excluded. Body weight, body condition score, auscultation, systolic blood pressure and two-dimensional (2-D) echocardiography were evaluated. Cats with left ventricular end-diastolic wall thickness ≥ 6 mm on 2-D echocardiography were considered to have HCM. Complete data were obtained in 780 cats. Heart murmur prevalence was 40.8% (95% confidence interval (CI) 37.3-44.3%), 70.4% of which were considered functional. The prevalence of HCM was 14.7% (95% CI 12.3-17.4%), congenital disease 0.5% (95% CI 0.1-1.3%), and other cardiomyopathies 0.1% (95% CI 0.0-0.7%). The HCM prevalence increased with age. The positive predictive value of a heart murmur for indicating HCM was 17.9-42.6% (higher in old cats), and the negative predictive value was 90.2-100% (higher in young cats). The factors associated with a diagnosis of HCM in binary logistic regression models were male sex, increased age, increased body condition score and a heart murmur (particularly grade III/VI or louder). Hypertrophic cardiomyopathy is common in apparently healthy cats, in contrast with other cardiomyopathies. Heart murmurs are also common, and are often functional. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Chronic Interactions Between Carotid Baroreceptors and Chemoreceptors in Obesity Hypertension.

    PubMed

    Lohmeier, Thomas E; Iliescu, Radu; Tudorancea, Ionut; Cazan, Radu; Cates, Adam W; Georgakopoulos, Dimitrios; Irwin, Eric D

    2016-07-01

    Carotid bodies play a critical role in protecting against hypoxemia, and their activation increases sympathetic activity, arterial pressure, and ventilation, responses opposed by acute stimulation of the baroreflex. Although chemoreceptor hypersensitivity is associated with sympathetically mediated hypertension, the mechanisms involved and their significance in the pathogenesis of hypertension remain unclear. We investigated the chronic interactions of these reflexes in dogs with sympathetically mediated, obesity-induced hypertension based on the hypothesis that hypoxemia and tonic activation of carotid chemoreceptors may be associated with obesity. After 5 weeks on a high-fat diet, the animals experienced a 35% to 40% weight gain and increases in arterial pressure from 106±3 to 123±3 mm Hg and respiratory rate from 8±1 to 12±1 breaths/min along with hypoxemia (arterial partial pressure of oxygen=81±3 mm Hg) but eucapnia. During 7 days of carotid baroreflex activation by electric stimulation of the carotid sinus, tachypnea was attenuated, and hypertension was abolished before these variables returned to prestimulation values during a recovery period. After subsequent denervation of the carotid sinus region, respiratory rate decreased transiently in association with further sustained reductions in arterial partial pressure of oxygen (to 65±2 mm Hg) and substantial hypercapnia. Moreover, the severity of hypertension was attenuated from 125±2 to 116±3 mm Hg (45%-50% reduction). These findings suggest that hypoxemia may account for sustained stimulation of peripheral chemoreceptors in obesity and that this activation leads to compensatory increases in ventilation and central sympathetic outflow that contributes to neurogenically mediated hypertension. Furthermore, the excitatory effects of chemoreceptor hyperactivity are abolished by chronic activation of the carotid baroreflex. © 2016 American Heart Association, Inc.

  4. Angioplasty and stent placement - carotid artery

    MedlinePlus

    ... in your carotid artery. Moving x-ray pictures (fluoroscopy) are used to see the artery and guide ... 18403765 . Kinlay S, Bhatt DL. Treatment of noncoronary obstructive ... versus surgery for asymptomatic carotid stenosis. N Engl J Med . ...

  5. Sympathoinhibition and hypotension in carotid sinus hypersensitivity

    NASA Technical Reports Server (NTRS)

    Smith, M. L.; Ellenbogen, K. A.; Eckberg, D. L.

    1992-01-01

    Carotid sinus reflex hypersensitivity is a known cause of syncope in humans. The condition is characterized by cardioinhibition and vasodepression, each to varying degrees. The extent and importance of sympathoinhibition has not been determined in patients with carotid sinus hypersensitivity. This study reports on the extent of sympathoinhibition measured directly directly during carotid massage with and without atrioventricular sequential pacing, in a patient with symptomatic carotid sinus reflex hypersensitivity. Carotid massage elicited asystole, hypotension and complete inhibition of muscle sympathetic nerve activity. Carotid massage during atrioventricular pacing produced similar sympathoinhibition, but with minimal hypotension. Therefore, sympathoinhibition did not contribute importantly to the hypotension during carotid massage in the supine position in this patient. Further investigations are required to elucidate the relation of sympathoinhibition to hypotension in patients with carotid sinus hypersensitivity in the upright position.

  6. Sympathoinhibition and hypotension in carotid sinus hypersensitivity

    NASA Technical Reports Server (NTRS)

    Smith, M. L.; Ellenbogen, K. A.; Eckberg, D. L.

    1992-01-01

    Carotid sinus reflex hypersensitivity is a known cause of syncope in humans. The condition is characterized by cardioinhibition and vasodepression, each to varying degrees. The extent and importance of sympathoinhibition has not been determined in patients with carotid sinus hypersensitivity. This study reports on the extent of sympathoinhibition measured directly directly during carotid massage with and without atrioventricular sequential pacing, in a patient with symptomatic carotid sinus reflex hypersensitivity. Carotid massage elicited asystole, hypotension and complete inhibition of muscle sympathetic nerve activity. Carotid massage during atrioventricular pacing produced similar sympathoinhibition, but with minimal hypotension. Therefore, sympathoinhibition did not contribute importantly to the hypotension during carotid massage in the supine position in this patient. Further investigations are required to elucidate the relation of sympathoinhibition to hypotension in patients with carotid sinus hypersensitivity in the upright position.

  7. Renal morphology in cats with diabetes mellitus.

    PubMed

    Zini, E; Benali, S; Coppola, L; Guscetti, F; Ackermann, M; Lutz, T A; Reusch, C E; Aresu, L

    2014-11-01

    In humans, diabetes mellitus (DM) is an important cause of renal damage, with glomerular lesions being predominant. In cats, although diabetes is a common endocrinopathy, it is yet unknown whether it leads to renal damage. The aim of the study was to compare renal histologic features and parameters of renal function in diabetic cats against a control population matched for age, gender, breed, and body weight. Thirty-two diabetic and 20 control cats were included. Kidney sections from paraffin-embedded kidney samples were stained and examined with optical microscopy to identify glomerular, tubulointerstitial, and vascular lesions and to assess their frequency and severity. Serum creatinine and urea concentrations were also compared. Glomerular lesions were observed in 29 cats overall, with mesangial matrix increase being more common (19 cats). Tubulointerstitial lesions were observed in 42 cats, including lymphocytic infiltration (29), fibrosis (22), or tubular necrosis (21). Vascular lesions were observed in 5 cases. The frequency and severity of histologic lesions did not differ between diabetic and control cats; however, among diabetics, those that survived longer after diagnosis had more glomerular and vascular lesions. Serum creatinine and urea concentrations were similar between groups; in diabetic cats median creatinine was 109 μmol/l (range, 51-1200) and urea was 12 mmol/l (range, 4-63), and in controls creatinine was 126 μmol/l (range, 50-875) and urea 11 mmol/l (range, 3-80). The results suggest that DM in cats does not lead to microscopically detectable kidney lesions or clinically relevant renal dysfunction. The authors hypothesize that the short life expectancy of diabetic cats may be the main reason for the difference from human diabetics. © The Author(s) 2014.

  8. The Short-Term Effect of Ketogenic Diet on Carotid Intima-Media Thickness and Elastic Properties of the Carotid Artery and the Aorta in Epileptic Children.

    PubMed

    Doksöz, Önder; Güzel, Orkide; Yılmaz, Ünsal; İşgüder, Rana; Çeleğen, Kübra; Meşe, Timur; Uysal, Utku

    2015-10-01

    The aim of this prospective study is to investigate the effect of a 6-month-long ketogenic diet on carotid intima-media thickness, carotid artery, and aortic vascular functions. Thirty-eight drug-resistant epileptic patients who were being treated with ketogenic diet were enrolled. Fasting total cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides, total cholesterol, and glucose concentrations were measured and echocardiography was performed in all patients before the beginning of ketogenic diet and at the sixth month of treatment. The body weight, height, body mass index, serum levels of triglyceride, total cholesterol, and low-density lipoprotein increased significantly at month 6 when compared to baseline values (P < .05). Carotid intima-media thickness, elastic properties of the aorta, and carotid artery did not change at the sixth month of therapy compared to baseline values. A 6-month-long ketogenic diet has no effect on carotid intima-media thickness and elastic properties of the carotid artery and the aorta.

  9. Physical activity level of adult cats with varied feeding frequency.

    PubMed

    Deng, Ping; Grant, Ryan W; Swanson, Kelly S

    2011-10-01

    The prevalence of feline obesity is influenced by numerous factors, including inactivity and overconsumption of food. The objective of the present study was to evaluate the effect of feeding frequency on physical activity in adult cats. A total of twelve healthy adult cats were used in a cross-over study consisting of 32 d. In each of the two periods, six cats were fed either two meals or four meals daily. Throughout the study, cats were fed the same diet at amounts to maintain body weight and body condition score. Cats were individually housed 4 h/d at each scheduled feeding time, while for the other 20 h, cats were group-housed to allow for voluntary physical activity in the room with a 16 h light-8 h dark cycle. Voluntary activity levels were evaluated using Actical activity collars for seven consecutive days in each period. Daily average activity level for two-meal-fed cats (20.04 (SEM 2.19), activity counts/epoch (15 s)) was not different from four-meal-fed cats (20.14 (SEM 2.15), activity counts/epoch (15 s); P>0.05). In conclusion, when group-housed cats are fed to maintain their body weight and body condition score, varied feeding frequency between twice and four times daily may not affect activity levels.

  10. Carotid bruits as predictor for carotid stenoses detected by ultrasonography: an observational study

    PubMed Central

    Johansson, Elias P; Wester, Per

    2008-01-01

    Background Carotid surgery in asymptomatic subjects with carotid stenosis is effective to prevent ischemic stroke. There is, however, uncertainty how to find such persons at risk, because mass screening with carotid artery ultrasonography (US) is not cost-effective. Signs of carotid bruits corresponding to the carotid arteries may serve as a tool to select subjects for further investigation. This study is thus aimed at determining the usefulness of carotid bruits in the screening of carotid stenoses. Methods 1555 consecutive carotid ultrasonography investigations from 1486 cases done between January 2004 and March 2006 at Norrlands University Hospital, Sweden, were examined. 356 subjects, medium age 69 (27–88) years, had a significant (≥ 50%) US-verified carotid stenosis uni- or bilaterally, 291 had been examined for signs of carotid bruits. The likelihood ratios for carotid bruits to predict US-verified carotid stenoses were calculated and expressed as likelihood percentages. Results Thirty-one out of 100 persons (31%) with carotid bruit as an indication to perform carotid US had a significant (≥ 50%) carotid stenosis. 281 of the 356 (79%) cases with significant carotid stenoses were found among patients with cerebrovascular disease (CVD). 145 of 226 (64%) CVD patients with a significant carotid stenosis had a carotid bruit. In patients with 50–99% carotid stenoses carotid bruits had an accuracy of 75% (436/582), a sensitivity of 71% (236/334), a specificity of 81% (200/248), a positive likelihood ratio at 3.65 and a negative likelihood at 0.36. Patients with 70–99% stenoses had the highest sensitivity at 77% (183/238). In patients with 100% carotid stenoses, carotid bruits had a sensitivity of 26% (15/57) and a specificity of 49% (256/525). Conclusion Although carotid bruits are not accurate to confirm or to exclude significant carotid stenoses, these signs are appropriate for directed screening for further investigation with carotid US if the patient

  11. Carotid-Femoral Pulse Wave Velocity: Impact of Different Arterial Path Length Measurements

    PubMed Central

    Sugawara, Jun; Hayashi, Koichiro; Yokoi, Takashi; Tanaka, Hirofumi

    2009-01-01

    Background Carotid-femoral pulse wave velocity (PWV) is the most established index of arterial stiffness. Yet there is no consensus on the methodology in regard to the arterial path length measurements conducted on the body surface. Currently, it is not known to what extent the differences in the arterial path length measurements affect absolute PWV values. Methods Two hundred fifty apparently healthy adults (127 men and 123 women, 19-79 years) were studied. Carotid-femoral PWV was calculated using (1) the straight distance between carotid and femoral sites (PWVcar–fem), (2) the straight distance between suprasternal notch and femoral site minus carotid arterial length (PWV(ssn–fem)-(ssn–car)), (3) the straight distance between carotid and femoral sites minus carotid arterial length (PWV(car–fem)-(ssn–car)), and (4) the combined distance from carotid site to the umbilicus and from the umbilicus to femoral site minus carotid arterial length (PWV(ssn–umb–fem)-(ssn–car)). Results All the calculated PWV were significantly correlated with each other (r=0.966-0.995). PWV accounting for carotid arterial length were 16-31% lower than PWVcar–fem. PWVcar–fem value of 12 m/sec corresponded to 8.3 m/sec for PWV(ssn–fem)-(ssn–car), 10.0 m/sec for PWV(car–fem)-(ssn–car), and 8.9 m/sec for PWV(ssn–umb–fem)-(ssn–car). Conclusion Different body surface measurements used to estimate arterial path length would produce substantial variations in absolute PWV values. PMID:20396400

  12. The reflex release of adrenaline and noradrenaline from the adrenal glands of cats and dogs.

    PubMed Central

    Critchley, J A; Ellis, P; Ungar, A

    1980-01-01

    1. We have studied the release of noradrenaline and adrenaline from the adrenal glands of dogs and cats in response to the lowering of carotid sinus pressure (baroreceptor tests) and to the perfusion of the vascularly isolated carotid bifurcations with hypoxic blood (chemoreceptor tests). 2. In cats, the resting output of catecholamines had a ratio of noradrenaline to adrenaline of 1:1. The ratio in the incremental release during baroreceptor tests rose to 3:1, and during chemoreceptor tests it fell to 1:6. 3. In dogs, the ratio of noradrenaline to adrenaline at rest was 1:4. The ratio did not change over a wide range of outputs during baroreceptor tests, chemoreceptor tests and splanchnic nerve stimulation. 4. The release of catecholamines in response to baroreceptor tests in the cat was abolished by hexamethomium bromide at doses that did not diminish the response to chemoreceptor tests. PMID:7359443

  13. Hypophosphatemia in cats after renal transplantation.

    PubMed

    Paster, Erin R; Mehl, Margo L; Kass, Philip H; Gregory, Clare R

    2009-12-01

    To report the prevalence of hypophosphatemia after renal transplantation in a historical cohort of cats. Case series. Cats (n=86) that received a renal allograft. Medical records (January 200-June 2006) were reviewed. Signalment, clinical signs, pre- and postoperative diet, pre- and postoperative clinicopathologic variables, renal histopathology, and outcome were retrieved. Prevalence, onset, duration, treatment and associated clinical signs of hypophosphatemia were recorded. A chi(2) test was used to compare hemolysis frequency between cats with normal serum phosphorus concentration or a single spurious low serum phosphorus concentration for <24 hours duration (group 1) and confirmed hypophosphatemia for >24 hours (group 2). A Cox proportional hazards model was used to evaluate the effects of hypophosphatemia on survival while controlling for other potentially confounding variables (age, sex, weight, body condition score, and pre- and 24 hours postoperative clinicopathologic variables). Eighty-six cats (mean age, 7.7 years) were identified. Hypophosphatemia occurred in 32 cats (37%), with a median onset of 2 days and median duration of 4 days. Treatment was initiated in 48 (56%) of hypophosphatemic cats. Survival and hemolysis frequency was not significantly different between groups, and no risk factors were identified. Hypophosphatemia occurs in cats after renal transplantation and does not affect survival. The clinical importance of hypophosphatemia in renal transplant recipients remains unknown.

  14. The effect of (+)-lysergic acid diethylamide and other drugs on the carotid sinus reflex

    PubMed Central

    Ginzel, K. H.

    1958-01-01

    In cats, lysergic acid diethylamide (LSD) selectively blocked the reflex blood pressure rise following carotid chemoreceptor stimulation. It also reduced or abolished the chemoreceptor component of the pressor response to occlusion of the common carotid arteries. It did not inhibit the respiratory reflexes arising from the carotid chemoreceptors, unless spontaneous respiration was interfered with as a whole. The site of action was central, probably below the intercollicular level, regardless of whether the drug was administered by the intravenous route or into the lateral ventricle of the brain. LSD did not block the baroreceptor depressor reflex elicited by stimulation of one carotid sinus nerve. LSD frequently caused the systemic pressure to fall, even after vagotomy and atropine, and this effect might account for the occasional reduction of the baroreceptor component of the carotid occlusion response. On the other hand, no relationship was found between the action of LSD on vasomotor tone and its blocking effect on the chemoreceptor pressor reflex. Some derivatives of LSD produced effects similar to those described for LSD, whether or not they possessed a psychotropic action in man, and independently of their efficiency as antagonists to 5-hydroxytryptamine. Of a series of compounds chemically unrelated to LSD, chlorpromazine was found to block the chemoreceptor pressor rise after intracerebroventricular injection. PMID:13584725

  15. Generation of cloned transgenic cats expressing red fluorescence protein.

    PubMed

    Yin, Xi Jun; Lee, Hyo Sang; Yu, Xian Feng; Choi, Eugene; Koo, Bon Chul; Kwon, Mo Sun; Lee, Young S; Cho, Su Jin; Jin, Guang Zhen; Kim, Lyoung Hyo; Shin, Hyoung Doo; Kim, Teoan; Kim, Nam Hyung; Kong, Il Keun

    2008-03-01

    A method for engineering and producing genetically modified cats is important for generating biomedical models of human diseases. Here we describe the use of somatic cell nuclear transfer to produce cloned transgenic cats that systemically express red fluorescent protein. Immature oocytes were collected from superovulating cat ovaries. Donor fibroblasts were obtained from an ear skin biopsy of a white male Turkish Angora cat, cultured for one to two passages, and subjected to transduction with a retrovirus vector designed to transfer and express the red fluorescent protein (RFP) gene. A total of 176 RFP cloned embryos were transferred into 11 surrogate mothers (mean = 16 +/- 7.5 per recipient). Three surrogate mothers were successfully impregnated (27.3%) and delivered two liveborn and one stillborn kitten at 65 to 66 days of gestation. Analysis of nine feline-specific microsatellite loci confirmed that the cloned cats were genetically identical to the donor cat. Presence of the RFP gene in the transgenic cat genome was confirmed by PCR and Southern blot analyses. Whole-body red fluorescence was detected 60 days after birth in the liveborn transgenic (TG) cat but not in the surrogate mother cat. Red fluorescence was detected in tissue samples, including hair, muscle, brain, heart, liver, kidney, spleen, bronchus, lung, stomach, intestine, tongue, and even excrement of the stillborn TG cat. These results suggest that this nuclear transfer procedure using genetically modified somatic cells could be useful for the efficient production of transgenic cats.

  16. Antiplatelet Therapy in Carotid Artery Stenting and Carotid Endarterectomy in the Asymptomatic Carotid Surgery Trial-2.

    PubMed

    Huibers, A; Halliday, A; Bulbulia, R; Coppi, G; de Borst, G J

    2016-03-01

    Strokes are infrequent but potentially serious complications following carotid intervention, but antiplatelet therapy can reduce these risks. There are currently no specific guidelines on dose or duration of peri-procedural antiplatelet treatment for patients undergoing carotid intervention. Within the ongoing Asymptomatic Carotid Surgery Trial-2 (ACST-2), this study aimed at assessing the current use of antiplatelet therapy before, during, and after CEA and CAS in patients with asymptomatic carotid stenosis. Questionnaires were sent to ACST-2 collaborators seeking information about the use of antiplatelet therapy during the pre-, peri-, and post-operative periods in patients undergoing carotid intervention at 77 participating sites and also whether sites tested for antiplatelet therapy resistance. The response rate was 68/77 (88%). For CAS, 82% of sites used dual antiplatelet therapy (DAPT) pre-operatively and 86% post-operatively with a mean post-procedural duration of 3 months (range 1-12), while 9% continued DAPT life-long. For CEA only 31% used DAPT pre-operatively, 24% post-operatively with a mean post-procedural duration of 3 months (range 1-5), while 10% continued DAPT life-long. For those prescribing post-procedural mono antiplatelet (MAPT) therapy (76%), aspirin was more commonly prescribed (59%) than clopidogrel (6%) and 11% of centres did not show a preference for either aspirin or clopidogrel. Eleven centres (16%) tested for antiplatelet therapy resistance. There appears to be broad agreement on the use of antiplatelet therapy in ACST-2 patients undergoing carotid artery stenting and surgery. Although evidence to help guide the duration of peri-procedural antiplatelet therapy is limited, long-term treatment with DAPT appears similar between both treatment arms. Copyright © 2015 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  17. Exocrine Pancreas in Cats With Diabetes Mellitus.

    PubMed

    Zini, E; Ferro, S; Lunardi, F; Zanetti, R; Heller, R S; Coppola, L M; Guscetti, F; Osto, M; Lutz, T A; Cavicchioli, L; Reusch, C E

    2016-01-01

    Pancreatitis has been described in cats with diabetes mellitus, although the number of studies currently available is very limited. In addition, ketoacidosis has been hypothesized to be associated with pancreatitis in diabetic cats. The aims of the present study were to investigate whether diabetic cats have pancreatitis and to determine if pancreatitis is more frequent with ketoacidosis. Samples of pancreas were collected postmortem from 37 diabetic cats, including 15 with ketoacidosis, and 20 control cats matched for age, sex, breed, and body weight. Sections were stained with hematoxylin and eosin, double-labeled for insulin/CD3, insulin/CD20, insulin/myeloperoxidase, insulin/PCNA, and glucagon/Ki67, and single-labeled for Iba1. A previously proposed semiquantitative score was used to characterize pancreatitis, along with counts of inflammatory cells. Scores of pancreatitis and the number of neutrophils, macrophages, and lymphocytes in the exocrine pancreas did not differ between diabetic and control cats or between diabetic cats with and without ketoacidosis. Of note, PCNA-positive acinar cells were increased (P = .002) in diabetic cats, particularly near islets (P < .001). Ki67-positive acinar cells were increased only near islets (P = .038). Ketoacidosis was not linked to proliferation. The results suggest that histopathologic evidence of pancreatitis may not be more frequent in diabetic cats and that ketoacidosis may not be associated with it at the time of death. Augmented PCNA-positive acinar cells might indicate increased proliferation due to chronic pancreatitis. The reason behind the prevalent proliferation of acinar cells surrounding pancreatic islets deserves further investigation. © The Author(s) 2015.

  18. Endocrine Pancreas in Cats With Diabetes Mellitus.

    PubMed

    Zini, E; Lunardi, F; Zanetti, R; Heller, R S; Coppola, L M; Ferro, S; Guscetti, F; Osto, M; Lutz, T A; Reusch, C E; Cavicchioli, L

    2016-01-01

    Pancreatic amyloidosis and loss of α and β cells have been shown to occur in cats with diabetes mellitus, although the number of studies currently available is very limited. Furthermore, it is not known whether pancreatic islet inflammation is a common feature. The aims of the present study were to characterize islet lesions and to investigate whether diabetic cats have inflammation of the pancreatic islets. Samples of pancreas were collected postmortem from 37 diabetic and 20 control cats matched for age, sex, breed, and body weight. Histologic sections were stained with hematoxylin and eosin and Congo red; double labeled for insulin/CD3, insulin/CD20, insulin/myeloperoxidase, insulin/proliferating cell nuclear antigen, and glucagon/Ki67; and single labeled for amylin and Iba1. Mean insulin-positive cross-sectional area was approximately 65% lower in diabetic than control cats (P = .009), while that of amylin and glucagon was similar. Surprisingly, amyloid deposition was similar between groups (P = .408). Proliferation of insulin- and glucagon-positive cells and the number of neutrophils, macrophages, and T (CD3) and B (CD20) lymphocytes in the islets did not differ. The presence of T and B lymphocytes combined tended to be more frequent in diabetic cats (n = 8 of 37; 21.6%) than control cats (n = 1 of 20; 5.0%). The results confirm previous observations that loss of β cells but not α cells occurs in diabetic cats. Islet amyloidosis was present in diabetic cats but was not greater than in controls. A subset of diabetic cats had lymphocytic infiltration of the islets, which might be associated with β-cell loss. © The Author(s) 2015.

  19. Dopamine inhibits ATP-induced responses in the cat petrosal ganglion in vitro.

    PubMed

    Alcayaga, Julio; Retamal, Mauricio; Cerpa, Verónica; Arroyo, Jorge; Zapata, Patricio

    2003-03-21

    The petrosal ganglion (PG) provides sensory innervation to the carotid sinus and carotid body through the carotid (sinus) nerve (CN). Application of either acetylcholine (ACh) or adenosine 5'-triphosphate (ATP) to the PG superfused in vitro activates CN fibers. Dopamine (DA) modulates the effects of ACh. We have previously shown that DA when applied to the PG modulates the effects of ACh on carotid sinus nerve fibers. We currently report the effects of DA on the ATP-induced responses in the isolated PG in vitro. While DA had no effect on the basal activity recorded from the CN, it reduced ATP-induced responses in a dose-dependent manner, when preceding ATP applications by 30 s. Our results suggest that DA-a transmitter present in a group of PG neurons and in carotid body cells-may act as an inhibitory modulator of ATP-evoked responses in PG neurons.

  20. Renal clearance of endogenous creatinine, urea, sodium, and potassium in normal cats and cats with chronic renal failure.

    PubMed

    Deguchi, E; Akuzawa, M

    1997-07-01

    The renal clearance test was carried out in 6 normal male cats and 12 male cats with chronic renal failure. The average concentrations of creatinine (Cr), urea, sodium (Na), and potassium (K) in the serum of the cats with chronic renal failure were 5.09, 136.7 (mg/100 ml), 143.9 and 3.71 (mEq/l) respectively, and the specific gravity of urine was 1.009. The renal clearances of Cr, urea, Na, and K (ml/min/kg of body weight) were 2.639 +/- 0.217, 1.034 +/- 0.110, 0.024 +/- 0.007 and 0.266 +/- 0.028, respectively in normal cats, and were 0.789 +/- 0.407, 0.358 +/- 0.211, 0.095 +/- 0.084 and 0.872 +/- 0.204 in cats with chronic renal failure. Clearance of Cr and urea was significantly lower in cats with chronic renal failure than in normal cats, while the values of Na and K were significantly higher in cats with chronic renal failure. The glomerular filtration of Cr and urea and the urinary excretion of these 4 substances were significantly higher in cats with chronic renal failure. The tubular reabsorption rates of Na and K were significantly lower in cats with chronic renal failure compared to those in normal cats, but there was no significant difference in urea and creatinine.

  1. Cat scratch encephalopathy.

    PubMed

    Silver, B E; Bean, C S

    1991-06-01

    Cat scratch disease is usually benign, self-limited and without sequelae. Margileth has established four clinical criteria, three of which must be satisfied to make the diagnosis: 1) a history of animal exposure, usually kitten, with primary skin or ocular lesions; 2) regional chronic adenopathy without other apparent cause; 3) a positive cat scratch disease antigen skin test; and 4) lymph node biopsy demonstrating noncaseating granulomas and germinal center hyperplasia. Central nervous system involvement in cat scratch disease has been previously reported, although it is extremely uncommon. In a several-month period, we encountered two cases of cat scratch disease complicated by encephalopathy. The intents of this paper are twofold: 1) to briefly review the current literature on cat scratch disease, 2) to demonstrate that cat scratch disease complicated by encephalopathy presents acutely with seizures, posturing and coma and resolves rapidly with supportive care.

  2. Cat-scratch Disease.

    PubMed

    Klotz, Stephen A; Ianas, Voichita; Elliott, Sean P

    2011-01-15

    Cat-scratch disease is a common infection that usually presents as tender lymphadenopathy. It should be included in the differential diagnosis of fever of unknown origin and any lymphadenopathy syndrome. Asymptomatic, bacteremic cats with Bartonella henselae in their saliva serve as vectors by biting and clawing the skin. Cat fleas are responsible for horizontal transmission of the disease from cat to cat, and on occasion, arthropod vectors (fleas or ticks) may transmit the disease to humans. Cat-scratch disease is commonly diagnosed in children, but adults can present with it as well. The causative microorganism, B. henselae, is difficult to culture. Diagnosis is most often arrived at by obtaining a history of exposure to cats and a serologic test with high titers (greater than 1:256) of immunoglobulin G antibody to B. henselae. Most cases of cat-scratch disease are self-limited and do not require antibiotic treatment. If an antibiotic is chosen, azithromycin has been shown in one small study to speed recovery. Infrequently, cat-scratch disease may present in a more disseminated form with hepatosplenomegaly or meningoencephalitis, or with bacillary angiomatosis in patients with AIDS.

  3. Barotrauma in a cat.

    PubMed

    Manning, M M; Brunson, D B

    1994-07-01

    A 3.5-year-old domestic long-hair cat was admitted to the veterinary hospital for routine procedures, including dental prophylaxis. The cat appeared clinically normal. General anesthesia was induced, and 30 minutes later, the pop-off valve was inadvertently left in a closed position. The cat developed pneumothorax, which was treated via thoracentesis and administration of oxygen. The condition resolved and the cat was released from the hospital to its owner. Barotrauma resulted because of high pressure in the anesthetic circuit. Barotrauma is a life-threatening complication of general anesthesia.

  4. The carotid rete and artiodactyl success.

    PubMed

    Mitchell, G; Lust, A

    2008-08-23

    Since the Eocene, the diversity of artiodactyls has increased while that of perissodactyls has decreased. Reasons given for this contrasting pattern are that the evolution of a ruminant digestive tract and improved locomotion in artiodactyls were adaptively advantageous in the highly seasonal post-Eocene climate. We suggest that evolution of a carotid rete, a structure highly developed in artiodactyls but absent in perissodactyls, was at least as important. The rete confers an ability to regulate brain temperature independently of body temperature. The net effect is that in hot ambient conditions artiodactyls are able to conserve energy and water, and in cold ambient conditions they are able to conserve body temperature. In perissodactyls, brain and body temperature change in parallel and thermoregulation requires abundant food and water to warm/cool the body. Consequently, perissodactyls occupy habitats of low seasonality and rich in food and water, such as tropical forests. Conversely, the increased thermoregulatory flexibility of artiodactyls has facilitated invasion of new adaptive zones ranging from the Arctic Circle to deserts and tropical savannahs.

  5. Metabolizable energy intake of client-owned adult cats.

    PubMed

    Thes, M; Koeber, N; Fritz, J; Wendel, F; Dobenecker, B; Kienzle, E

    2015-12-01

    A retrospective analysis of the metabolizable energy (ME) intake of privately owned pet cats from the authors' nutrition consultation practice (years 2007-2011) was carried out to test whether current recommendations are suitable for pet cats. Data of 80 adult cats (median age: 9.0 years, median deviation from ideal weight: +22.5%, majority neutered) at maintenance were available. Six percentage of the cats were healthy and the others were affected by various chronic diseases. A standardized questionnaire was used, cat owners weighed cat and food. For ration calculation, the software Diet Check Munich(™) was used (ME prediction according to National Research Council, 2006: Nutrient Requirements of Dogs and Cats. National Academy Press, Washington, DC). Data were analysed for the factors deviation from ideal weight, breed, age, gender, disease and type of feeding [prepared food (dry, wet) vs. home-made]. Over- or underweight were defined as ≥15% deviation from ideal body weight (BW) according to Kienzle and Moik (British Journal of Nutrition 2011, 106, Suppl 1: S113). Cat owner's estimation of ideal BW was higher than literature data from Kienzle and Moik (2011). Based on literature data, 26.3% of the pet cats were normal weight, 63.7% overweight and 10% underweight. The mean ME intake of all adult cats amounted to 0.40 ± 0.14 MJ/kg actual BW(0.67) (n = 80). When the data were analysed according to normal, over- and underweight, there was a significant effect with normal weight cats eating 0.46 MJ/kg BW(0.67) . Underweight cats ate even more (0.49 MJ/kg BW(0.67) ), whereas overweight cats ate considerably less (0.36 MJ/kg BW(0.67) ). The other factors had no influence on ME intake of adult cats.

  6. Incidence of and risk factors for diabetes mellitus in cats that have undergone renal transplantation: 187 cases (1986-2005).

    PubMed

    Case, Joseph B; Kyles, Andrew E; Nelson, Richard W; Aronson, Lillian; Kass, Philip H; Klose, Tyler C; Bailiff, Nathan L; Gregory, Clare R

    2007-03-15

    To compare incidence of diabetes mellitus in cats that had undergone renal transplantation with incidence in cats with chronic renal failure, compare mortality rates in cats that underwent renal transplantation and did or did not develop diabetes mellitus, and identify potential risk factors for development of posttransplantation diabetes mellitus (PTDM) in cats. Retrospective case series. 187 cats that underwent renal transplantation. Medical records were reviewed. 26 of the 187 (13.9%) cats developed PTDM, with the incidence of PTDM being 66 cases/1,000 cat years at risk. By contrast, the incidence of diabetes mellitus among a comparison population of 178 cats with chronic renal failure that did not undergo renal transplantation was 17.9 cases/1,000 cat years at risk, and cats that underwent renal trans-plantation were 5.45 times as likely to develop diabetes mellitus as were control cats with chronic renal failure. The mortality rate among cats with PTDM was 2.38 times the rate among cats that underwent renal transplantation but did not develop PTDM. Age, sex, body weight, and percentage change in body weight were not found to be significantly associated with development of PTDM. Results suggest that cats that undergo renal transplantation have an increased risk of developing diabetes mellitus, compared with cats with chronic renal failure, and that mortality rate is higher for cats that develop PTDM than for cats that do not.

  7. Resection of a large carotid paraganglioma in Carney-Stratakis syndrome: a multidisciplinary feat

    PubMed Central

    Nicholas, Rebecca Spenser; Quddus, Ayyaz; Topham, Charlotte; Baker, Daryll

    2015-01-01

    A 39-year-old man was referred to the vascular surgeons with a right-sided cervical mass, palpitations, headaches and sweating. He had presented with abdominal discomfort 12 months earlier. Investigations had revealed a gastrointestinal stromal tumour (GIST) and left adrenalectomy. CT of the neck with contrast demonstrated a large right carotid paraganglioma, extending superiorly from below the carotid bifurcation to encase the internal carotid artery. Genetic screening confirmed the diagnosis of Carney-Stratakis syndrome, an SDH-D germline mutation leading to GIST and multifocal paragangliomas. Successful surgical excision required considerable multidisciplinary teamwork between neuroendocrinologists, anaesthetists and surgeons. The tumour was highly vascular and involved the right carotid body, hypoglossal and vagus nerves. Access was challenging and maxillofacial surgical expertise were required for division of the mandible. The patient made a good recovery following speech and swallowing rehabilitation. PMID:25883251

  8. Ultrasonographically assessed carotid intima-media thickness and risk for asymptomatic cerebral infarction.

    PubMed

    Yamakado, M; Fukuda, I; Kiyose, H

    1998-02-01

    Cerebral infarction (CI) is still a leading cause of death in Japan. Thus, the management of risk factors for CI as primary prevention is one of the most important tasks in multiphasic health testing and services. To determine whether carotid intima-media thickness (IMT) is a risk for CI, ultrasonographically assessed carotid IMT was compared between normal subjects (N) and subjects with asymptomatic CI (ACI) in 243 subjects who underwent human brain dry dock. ACI was found in 68 people (28.0%). Age, body mass index, and mean blood pressure were higher in ACI than in N. Also, atherogenic index was higher in ACI than in N. Carotid IMT was significantly thicker in ACI than in N. Furthermore, incidence of atherogenic plaque in ACI was significantly higher than that in N. In conclusion, not only aging, obesity, blood pressure, and plasma lipids, but also carotid IMT may be a risk for ACI.

  9. Selection of treatment for patients with carotid artery disease: medication, carotid endarterectomy, or carotid artery stenting