Science.gov

Sample records for acutely dissociated neurons

  1. Efficacy and kinetics of opioid action on acutely dissociated neurons.

    PubMed

    Ingram, S; Wilding, T J; McCleskey, E W; Williams, J T

    1997-07-01

    Opioids have been shown to cause a potent inhibition of neurons in the locus ceruleus (LC) in vivo in brain slices and isolated neurons; however, the kinetics of opioid action have not been described. In this study, we used acutely isolated LC neurons to examine opioid and alpha2-adrenoceptor action on potassium and calcium currents. [Met]Enkephalin (ME), [D-Ser2,Leu5,Thr6]-enkephalin, etorphine, and [D-Ala2,N-Me-Phe4,Gly-ol5]enkephalin increased potassium conductance, whereas morphine and naloxone were antagonists. The time constant of potassium channel activation was approximately 0.7 sec and was the same for each agonist. The amplitude of the current and the time constant of decay were dependent on the agonist, suggesting that agonist efficacy and affinity, respectively, determined these parameters. The amplitude of potassium current induced by the alpha2-adrenoceptor agonist UK14304 was not significantly different from that induced by ME, but the time constant of current activation was half that of ME, and the decline was more rapid. When potassium conductances were blocked with the combination of internal cesium and external barium, opioid and alpha2 agonists had no effect at potentials more negative than -50 mV and decreased barium currents at potentials between -40 and +20 mV. Both morphine and clonidine caused a small inhibition of barium current. In dorsal root ganglion cells, morphine alone had small and inconsistent effects on the calcium current, but it always competitively antagonized the inhibition caused by [D-Ala2,N-Me-Phe4,Gly-ol5]enkephalin. The results in isolated LC neurons suggest 1) the amplitude and time course of the opioid-induced potassium current depend on agonist efficacy and affinity and 2) the coupling of both mu-opioid and alpha2-adrenoceptors to calcium channels seems to be more efficient than that to potassium channels.

  2. alpha2-Adrenoceptor-mediated potassium currents in acutely dissociated rat locus coeruleus neurones.

    PubMed

    Arima, J; Kubo, C; Ishibashi, H; Akaike, N

    1998-04-01

    1. The noradrenaline (NA)-activated response was investigated in neurones acutely dissociated from the rat locus coeruleus (LC) using nystatin-perforated, conventional whole-cell and inside-out patch recording modes under current- and voltage-clamp conditions. 2. Under current-clamp conditions, NA hyperpolarized the LC neurones, abolishing the spontaneous action potentials. In voltage-clamp studies, NA induced an inwardly rectifying K+ current (INA) in a concentration-dependent manner with a half-maximum effective concentration of 2.2 x 10(-7) M. 3. INA was mimicked by the alpha2-agonist UK14304 but was inhibited by either the alpha2B/alpha2C antagonist ARC239 or the alpha1- and alpha2B/alpha2C antagonist prazosin, suggesting the contribution of alpha2B/alpha2C adrenoceptors. 4. INA was inhibited by the intracellular application of GDPbetaS but fully activated by intracellular perfusion of GTPgammaS. 5. In the inside-out recording mode, the application of GTP to the cytoplasmic side of the patch membrane markedly enhanced the open probability of the NA-activated single channels which represented the inwardly rectifying properties. 6. These results indicate that the activation of alpha2B/alpha2C adrenoceptors coupled with GTP-binding protein directly activates the inwardly rectifying K+ currents in rat LC neurones, thus resulting in a decrease in the spontaneous firing activities.

  3. Characteristics of multiple Ca(2+)-activated K+ channels in acutely dissociated chick ciliary-ganglion neurones.

    PubMed Central

    Dryer, S E; Dourado, M M; Wisgirda, M E

    1991-01-01

    1. Whole-cell and single-channel recordings were used to characterize Ca(2+)-activated K+ channels (IK(Ca)) in acutely dissociated chick-ganglion neurones. 2. Application of depolarizing voltage steps resulted in outward currents that could be separated according to their dependence on external Ca2+ and/or holding potential. IK(Ca) was the only outward current that could be evoked from holding potentials of -50 mV or less. IK(Ca) was eliminated by bath application of Ca(2+)-free salines. A voltage-dependent outward current (IK(V)) could be evoked from more negative holding potentials in Ca(2+)-free salines. IK(V) was only partially blocked by as much as 30 mM-tetraethylammonium (TEA). 3. Tail currents associated with IK(Ca) reversed close to the K+ equilibrium potential (EK). IK(Ca) tail currents appeared sigmoidal, but the falling phase of the tail currents could be fitted with exponential curves that decayed faster at more negative membrane potentials. 4. IK(Ca) was blocked completely and reversibly by 10 mM-TEA. IK(Ca) was substantially reduced (80-90%) by as little as 1 mM-TEA. 5. Total IK(Ca) was reduced but not eliminated by saturating concentrations of apamin (200 nM). This blockade was not reversible with up to 30 min of washing. Application of 100 microM-d-tubocurare (dTC) also produced a partial blockade of total IK(Ca). 6. Whole-cell current-clamp recordings showed that IK(Ca) contributed to the late phases of spike repolarization and was the dominant current flowing during the spike after-hyperpolarization (AHP). Application of 200 nM-apamin caused a reduction in the duration of the AHP. This reduction was best seen when multiple spikes were evoked by prolonged (20-50 ms) injections of depolarizing current. 7. Three distinct types of IK(Ca) channels could be observed in inside-out patches in the presence of free Ca2+ concentrations of 2 x 10(-7) M, but not in the presence of free Ca2+ at concentrations of less than 10(-9) M. These had unitary chord

  4. Metabotropic glutamate response in acutely dissociated hippocampal CA1 pyramidal neurones of the rat.

    PubMed Central

    Shirasaki, T; Harata, N; Akaike, N

    1994-01-01

    1. The metabotropic glutamate (mGlu) response was investigated in dissociated rat hippocampal CA1 pyramidal neurones using conventional and nystatin-perforated whole-cell modes of the patch recording configuration. 2. In the perforated patch recording configuration, the application of glutamate (Glu), quisqualate (QA), aspartate (Asp) and N-methyl-D-aspartate (NMDA) induced a slow outward current superimposed on a fast ionotropic inward current, whereas alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) and kainate (KA) induced only an ionotropic inward current at a holding potential (VH) of -20 mV. A specific agonist of the mGlu receptor (mGluR), trans-1-aminocyclopentane-1,3-dicarboxylate (tACPD), induced an outward current in approximately 80% of the neurones tested. Asp- and NMDA-induced outward currents were antagonized by D-2-amino-5-phosphonopentanoate (D-AP5) whereas Glu-, QA- and tACPD-induced outward currents were not antagonized by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), 6,7-dinitroquinoxaline-2,3-dione (DNQX) and D-AP5, indicating that the mGlu response is an outward current component. 3. L-2-Amino-3-phosphonopropionate (L-AP3) and DL-2-amino-4-phosphonobutyrate (AP4) did not block the mGlu response. 4. The relative potencies of mGlu agonists were QA > Glu > tACPD. The threshold and EC50 values of metabotropic outward currents were 10-100 times lower than those of the ionotropic inward current (iGlu response). 5. The reversal potential of the mGlu response (EmGlu) was close to EK (K+ equilibrium potential), and it shifted 59.5 mV for a tenfold change in extracellular K+ concentration. 6. In Ca(2+)-free external solution, the mGlu response was elicited by an initial application of Glu, but subsequent applications failed to induce the response. There was also an increase in the intracellular free Ca2+ concentration ([Ca2+]i) during the application of Glu and QA but not of AMPA, indicating Ca2+ release from an intracellular Ca2+ store. 7

  5. Run-down of the GABAA response under experimental ischaemia in acutely dissociated CA1 pyramidal neurones of the rat.

    PubMed Central

    Harata, N; Wu, J; Ishibashi, H; Ono, K; Akaike, N

    1997-01-01

    1. The effect of experimental ischaemia on the response to gamma-aminobutyric acid (GABA) was assessed in acutely dissociated CA1 pyramidal neurones of rats, using the patch-clamp technique. 2. Rapid application of 3 x 10(-5) M GABA induced a bicuculline-sensitive inward Cl- current (IGABA) at a holding potential (Vh) of -44 mV. The peak amplitude of IGABA showed a time-dependent decrease (run-down) when it was recorded with the conventional whole-cell mode without internal ATP. The run-down was not observed when the intracellular ATP concentration ([ATP]i) was maintained by the nystatin-perforated recording with an intracellular Na+ concentration ([Na+]i) of 0 mM. 3. When [Na+]i was increased to more than 30 mM, the IGABA run-down was observed even with the nystatin-perforated recording. 4. The IGABA run-down observed at 60 mM [Na+]i with the nystatin method was further enhanced under experimental ischaemia without changes in the reversal potential of IGABA. The enhanced run-down was suppressed by application of the Na+,K(+)-ATPase inhibitors, ouabain and SPAI-1. 5. IGABA run-down during ischaemia was also accompanied by an outward holding current and a concomitant increase in intracellular free Ca2+ concentration ([Ca2+]i) in 48.5% of the neurones. The outward current was a Ca(2+)-activated K+ current, which was blocked by 3 x 10(-7) M charybdotoxin. 6. In the inside-out mode of the single-channel analysis, GABA activated three subconductance states with conductances of 33.4, 22.7 and 15.2 pS. Reduction of ATP concentration from 2 to 0 mM on the intracellular side suppressed the channel activities, while an increase in Ca2+ concentration from 0.7 x 10(-9) to 1.1 x 10(-6) M had no effect. 7. These results suggest that ischaemia induces the run-down of the postsynaptic GABA response at the GABAA receptor level, and that this run-down is triggered by a decrease in [ATP]i. Images Figure 3 Figure 4 Figure 5 Figure 6 PMID:9161985

  6. Mechanical Dissociation of Retinal Neurons with Vibration

    NASA Astrophysics Data System (ADS)

    Motomura, Tamami; Hayashida, Yuki; Murayama, Nobuki

    The neuromorphic device, which implements the functions of biological neural circuits by means of VLSI technology, has been collecting much attention in the engineering fields in the last decade. Concurrently, progress in neuroscience research has revealed the nonlinear computation in single neuron levels, suggesting that individual neurons are not merely the circuit elements but computational units. Thus, elucidating the properties of neuronal signal processing is thought to be an essential step for developing the next generation of neuromorphic devices. In the present study, we developed a method for dissociating single neurons from specific sublayers of mammalian retinas with using no proteolytic enzymes but rather combining tissue incubation in a low-Ca2+ medium and the vibro-dissociation technique developed for the slices of brains and spinal cords previously. Our method took shorter time of the procedure, and required less elaborated skill, than the conventional enzymatic method did; nevertheless it yielded enough number of the cells available for acute electrophysiological experiments. The isolated retinal neurons were useful for measuring the nonlinear membrane conductances as well as the spike firing properties under the perforated-patch whole-cell configuration. These neurons also enabled us to examine the effects of proteolytic enzymes on the membrane excitability in those cells.

  7. PRIMARY CULTURES OF DISSOCIATED SYMPATHETIC NEURONS

    PubMed Central

    Mains, Richard E.; Patterson, Paul H.

    1973-01-01

    Rat sympathetic ganglia were disrupted by mechanical agitation to yield dissociated primary neurons, and the conditions for long-term growth in culture of the isolated neurons were examined. The neurons were grown with or without non-neural cells, simply by the addition or deletion of bicarbonate during growth in culture. Fluorescence histochemistry indicated that the isolated neurons contained catecholamines; incubations with radioactive precursors were used to verify the synthesis and accumulation of both dopamine and norepinephrine. The neurons also produced octopamine using tyramine as precursor, but not with tyrosine as the precursor. In the presence of eserine, older cultures synthesized and stored small amounts of acetylcholine. The cultures did not synthesize and accumulate detectable levels of radioactive γ-aminobutyric acid, 5-hydroxytryptamine, or histamine. PMID:4616046

  8. Peritraumatic versus persistent dissociation in acute stress disorder.

    PubMed

    Panasetis, Paula; Bryant, Richard A

    2003-12-01

    The DSM-IV definition of acute stress disorder (ASD) regards dissociation that occurs during a trauma (peritraumatic dissociation) comparably to persistent dissociation. This study investigated the relative contributions of peritraumatic dissociation and persistent dissociation to acute posttraumatic stress reactions. Civilian trauma (N = 53) survivors with either acute stress disorder (ASD), subclinical ASD, or no ASD were administered modified versions of the Peritraumatic Dissociative Experiences Questionnaire that indexed both dissociation during the trauma and dissociation at the time of assessment. Persistent dissociation was more strongly associated with ASD severity and intrusive symptoms than peritraumatic dissociation. These results are consistent with the proposition that persistent, rather than peritraumatic, dissociation is associated with posttraumatic psychopathology.

  9. Self-organization and neuronal avalanches in networks of dissociated cortical neurons.

    PubMed

    Pasquale, V; Massobrio, P; Bologna, L L; Chiappalone, M; Martinoia, S

    2008-06-02

    Dissociated cortical neurons from rat embryos cultured onto micro-electrode arrays exhibit characteristic patterns of electrophysiological activity, ranging from isolated spikes in the first days of development to highly synchronized bursts after 3-4 weeks in vitro. In this work we analyzed these features by considering the approach proposed by the self-organized criticality theory: we found that networks of dissociated cortical neurons also generate spontaneous events of spreading activity, previously observed in cortical slices, in the form of neuronal avalanches. Choosing an appropriate time scale of observation to detect such neuronal avalanches, we studied the dynamics by considering the spontaneous activity during acute recordings in mature cultures and following the development of the network. We observed different behaviors, i.e. sub-critical, critical or super-critical distributions of avalanche sizes and durations, depending on both the age and the development of cultures. In order to clarify this variability, neuronal avalanches were correlated with other statistical parameters describing the global activity of the network. Criticality was found in correspondence to medium synchronization among bursts and high ratio between bursting and spiking activity. Then, the action of specific drugs affecting global bursting dynamics (i.e. acetylcholine and bicuculline) was investigated to confirm the correlation between criticality and regulated balance between synchronization and variability in the bursting activity. Finally, a computational model of neuronal network was developed in order to interpret the experimental results and understand which parameters (e.g. connectivity, excitability) influence the distribution of avalanches. In summary, cortical neurons preserve their capability to self-organize in an effective network even when dissociated and cultured in vitro. The distribution of avalanche features seems to be critical in those cultures displaying

  10. Potentiation by sevoflurane of the gamma-aminobutyric acid-induced chloride current in acutely dissociated CA1 pyramidal neurones from rat hippocampus.

    PubMed Central

    Wu, J.; Harata, N.; Akaike, N.

    1996-01-01

    1. The effects of a new kind of volatile anaesthetic, sevoflurane (Sev), on gamma-aminobutyric acid (GABA)-gated chloride current (Icl) in single neurones dissociated from the rat hippocampal CA1 area were examined using the nystatin perforated patch recording configuration under the voltage-clamp condition. All drugs were applied with a rapid perfusion system, termed the "Y-tube' method. 2. When the concentrations were higher than 3 x 10(-4) M, Sev, itself, induced an inward current (ISev) at a holding potential (VH) of -40 mV. The concentration-response curve of ISev was bell-shaped, with a suppressed peak and plateau currents at high concentrations (above 2 x 10(-3) M). The reversal potential of ISev (ESev) was close to the theoretical Cl- equilibrium potential, indicating that ISev was carried mainly by Cl-. 3. ISev was reversibly blocked by bicuculline (Bic), an antagonist of the GABAA receptor, in a concentration-dependent manner with a half-inhibitory concentration (IC50) of 7.2 x 10(-7) M. But ISev was insensitive to strychnine (Str), an antagonist of the glycine receptor. 4. At low concentrations (between 3 x 10(-4) and 10(-3) M), Sev markedly enhanced the 10(-6) M GABA induced current (IGABA) but reduced the IGABA with accelerating desensitization accompanied by a "hump' current after washout at high concentrations (higher than 2 x 10(-3) M). 5. Sev, 10(-3) M potentiated the current induced by low concentrations of GABA (between 10(-7) and 3 x 10(-6) M) but reduced the current induced by high concentrations (higher than 10(-5) M) of GABA with a clear acceleration of IGABA desensitization. 6. Sev, like pentobarbitone (PB), pregnanolone (PGN) or diazepam (DZP), potentiated the 10(-6) M GABA-induced response without shifting the reversal potential of IGABA. 7. ISev was augmented by PB, PGN, or DZP at concentrations that maximally potentiated IGABA, suggesting that Sev enhanced IGABA at a binding site distinct from that for PB, PGN, or DZP. 8. It is concluded

  11. Ionic mechanisms of burst firing in dissociated Purkinje neurons.

    PubMed

    Swensen, Andrew M; Bean, Bruce P

    2003-10-22

    Cerebellar Purkinje neurons have intrinsic membrane properties that favor burst firing, seen not only during complex spikes elicited by climbing fiber input but also with direct electrical stimulation of cell bodies. We examined the ionic conductances that underlie all-or-none burst firing elicited in acutely dissociated mouse Purkinje neurons by short depolarizing current injections. Blocking voltage-dependent calcium entry by cadmium or replacement of external calcium by magnesium enhanced burst firing, but it was blocked by cobalt replacement of calcium, probably reflecting block of sodium channels. In voltage-clamp experiments, we used the burst waveform of each cell as a voltage command and used ionic substitutions and pharmacological manipulations to isolate tetrodotoxin (TTX)-sensitive sodium current, P-type and T-type calcium current, hyperpolarization-activated cation current (Ih), voltage-activated potassium current, large-conductance calcium-activated potassium current, and small-conductance calcium-activated potassium (SK) current. Measured near the middle of the first interspike interval, TTX-sensitive sodium current carried the largest inward current, and T-type calcium current was also substantial. Current through P-type channels was large immediately after a spike but decayed rapidly. These inward currents were opposed by substantial components of voltage-dependent and calcium-dependent potassium current. Termination of the burst is caused partly by decay of sodium current, together with a progressive buildup of SK current after the first interspike interval. Although burst firing depends on the net balance between multiple large currents flowing after a spike, it is surprisingly robust, probably reflecting complex interactions between the exact voltage waveform and voltage and calcium dependence of the various currents.

  12. [Electrophysiological properties of inhibitory neurones in cultured dissociated hippocampal cells].

    PubMed

    Moskaliuk, A O; Kolodin, Iu O; Kravchenko, M O; Fedulova, S A; Veselovs'kyĭ, M S

    2004-01-01

    Electrophysiological properties of inhibitory (GABAergic) neurones were studied in dissociated hippocampal culture using simultaneous whole cell recordings from pairs of monosynaptically coupled neurons. Reliable identification of GABAergic neuron was performed by presence of monosynaptic inhibitory currents at postsynaptic cell in response to action potentials at stimulated cell. It was shown that GABAergic neurons in hippocampal culture are divided in two groups by their firing characteristics: first type generates action potentials at high frequency in response to injection of current (duration 0.5 s)--fast-spiking neurons (FS), cells from second type has no ability for high-frequency action potential generation--regular spiking neurons (RS). These two groups were distinguished by kinetic characteristics of action potentials, adaptation characteristics during continuous generation of action potentials and inhibitory effect making on postsynaptic cell. Application of potassium channel blocker 4-AP to somas of FS neurons in concentration, which selectively inhibits Kv3 potassium channels evoked reversible changes in kinetic of action potentials, frequency and adaptation characteristics during continuous generation of action potentials. It was concluded that there is hight level of expression of Kv3 potassium channels in the first group of neurons.

  13. Switch Function and Pathological Dissociation in Acute Psychiatric Inpatients

    PubMed Central

    Chiu, Chui-De; Tseng, Mei-Chih Meg; Chien, Yi-Ling; Liao, Shih-Cheng; Liu, Chih-Min; Yeh, Yei-Yu; Hwu, Hai-Gwo

    2016-01-01

    Swift switching, along with atypical ability on updating and inhibition, has been found in non-clinical dissociators. However, whether swift switching is a cognitive endophenotype that intertwines with traumatisation and pathological dissociation remains unknown. Unspecified acute psychiatric patients were recruited to verify a hypothesis that pathological dissociation is associated with swift switching and traumatisation may explain this relationship. Behavioural measures of intellectual function and three executive functions including updating, switching and inhibition were administered, together with standardised scales to evaluate pathological dissociation and traumatisation. Our results showed superior control ability on switching and updating in inpatients who displayed more symptoms of pathological dissociation. When all three executive functions were entered as predictors, in addition to intellectual quotient and demographic variables to regress upon pathological dissociation, switching rather than updating remained the significant predictor. Importantly, the relationship between pathological dissociation and switching became non-significant when the effect of childhood trauma were controlled. The results support a trauma-related switching hypothesis which postulates swift switching as a cognitive endophenotype of pathological dissociation; traumatisation in childhood may explain the importance of swift switching. PMID:27123578

  14. Dissociative disorders in acute psychiatric inpatients in Taiwan.

    PubMed

    Chiu, Chui-De; Meg Tseng, Mei-Chih; Chien, Yi-Ling; Liao, Shih-Cheng; Liu, Chih-Min; Yeh, Yei-Yu; Hwu, Hai-Gwo; Ross, Colin A

    2017-04-01

    Dissociative disorders have been documented to be common psychiatric disorders which can be detected reliably with standardized diagnostic instruments in North American and European psychiatric inpatients and outpatients (20.6% and 18.4%, respectively). However, there are concerns about their cross-cultural manifestations as an apparently low prevalence rate has been reported in East Asian inpatients and outpatients (1.7% and 4.9%, respectively). It is unknown whether the clinical profile of dissociative disorders in terms of their core symptomatic clusters, associated comorbid disorders, and environmental risk factors that has emerged in western clinical populations can also be found in non-western clinical populations. A standardized structured interview for DSM-IV dissociative disorders, post-traumatic stress disorder, and a history of interpersonal victimization was administered in a sample of Taiwanese acute psychiatric inpatients. Our results showed that 19.5% of our participants met criteria for a DSM-IV dissociative disorder, mostly dissociative disorder not otherwise specified. More importantly, the western clinical profile of dissociative disorders also characterized our patients, including a poly-symptomatic presentation and a history of interpersonal trauma in both childhood and adulthood. Our results lend support to the conclusion that cross-cultural manifestations of dissociative pathology in East Asia are similar to those in North America and Europe.

  15. Dissociation of dorsal root ganglion neurons induces hyperexcitability that is maintained by increased responsiveness to cAMP and cGMP.

    PubMed

    Zheng, Ji-Hong; Walters, Edgar T; Song, Xue-Jun

    2007-01-01

    Injury or inflammation affecting sensory neurons in dorsal root ganglia (DRG) causes hyperexcitability of DRG neurons that can lead to spontaneous firing and neuropathic pain. Recent results indicate that after chronic compression of DRG (CCD treatment), both hyperexcitability of neurons in intact DRG and behaviorally expressed hyperalgesia are maintained by concurrent activity in cAMP-protein kinase A (PKA) and cGMP-protein kinase G (PKG) signaling pathways. We report here that when tested under identical conditions, dissociation produces a pattern of hyperexcitability in small DRG neurons similar to that produced by CCD treatment, manifest as decreased action potential (AP) current threshold, increased AP duration, increased repetitive firing to depolarizing pulses, increased spontaneous firing and resting depolarization. A novel feature of this hyperexcitability is its early expression-as soon as testing can be conducted after dissociation (approximately 2 h). Both forms of injury increase the electrophysiological responsiveness of the neurons to activation of cAMP-PKA and cGMP-PKG pathways as indicated by enhancement of hyperexcitability by agonists of these pathways in dissociated or CCD-treated neurons but not in control neurons. Although inflammatory signals are known to activate cAMP-PKA pathways, dissociation-induced hyperexcitability is unlikely to be triggered by signals released from inflammatory cells recruited to the DRG because of insufficient time for recruitment during the dissociation procedure. Inhibition by specific antagonists indicates that continuing activation of cAMP-PKA and cGMP-PKG pathways is required to maintain hyperexcitability after dissociation. The reduction of hyperexcitability by blockers of adenylyl cyclase and soluble guanylyl cyclase after dissociation suggests a continuing release of autocrine and/or paracrine factors from dissociated neurons and/or satellite cells, which activate both cyclases and help to maintain acute

  16. Acute dissociation predicts rapid habituation of skin conductance responses to aversive auditory probes.

    PubMed

    Giesbrecht, Timo; Merckelbach, Harald; ter Burg, Linda; Cima, Maaike; Simeon, Daphne

    2008-04-01

    The present study examined how acute dissociation, trait-like dissociative symptoms, and physiological reactivity relate to each other. Sixty-nine undergraduate students were exposed to 14 aversive auditory probes, while their skin conductance responses were measured. A combination of self-reported anxiety and trait-like dissociation was found to predict variability in peritraumatic dissociation levels induced by the aversive probes. Furthermore, high levels of acute dissociation were associated with faster habituation of skin conductance responding, while trait-like dissociation was unrelated to habituation. Interestingly, individuals who reported childhood trauma displayed elevated skin conductance responses. Our findings contribute to the growing body of evidence indicating that subjective feelings of acute dissociation have their objective concomitants, notably fast habituation of physiologic responses.

  17. Dissociation between two subgroups of the suprachiasmatic nucleus affected by the number of damped oscillated neurons

    NASA Astrophysics Data System (ADS)

    Gu, Changgui; Yang, Huijie; Rohling, Jos HT

    2017-03-01

    In mammals, the main clock located in the suprachiasmatic nucleus (SCN) of the brain synchronizes the body rhythms to the environmental light-dark cycle. The SCN is composed of about 2 ×104 neurons which can be classified into three oscillatory phenotypes: self-sustained oscillators, damped oscillators, and arrhythmic neurons. Exposed to an artificial external light-dark cycle with a period of 22 h instead of 24 h , two subgroups of the SCN can become desynchronized (dissociated). The ventrolateral (VL) subgroup receives photic input and is entrained to the external cycle and a dorsomedial (DM) subgroup oscillates with its endogenous (i.e., free running) period and is synchronized to the external light-dark cycle through coupling from the VL. In the present study, we examined the effects of damped oscillatory neurons on the dissociation between VL and DM under an external 22 h cycle. We found that, with increasing numbers of damped oscillatory neurons located in the VL, the dissociation between the VL and DM emerges, but if these neurons are increasingly present in the DM the dissociation disappears. Hence, the damped oscillatory neurons in different subregions of the SCN play distinct roles in the dissociation between the two subregions of the SCN. This shows that synchrony between SCN subregions is affected by the number of damped oscillatory neurons and the location of these cells. We suggest that more knowledge on the number and the location of these cells may explain why some species do show a dissociation between the subregions and others do not, as the distribution of oscillatory types of neurons offers a plausible and novel candidate mechanism to explain heterogeneity.

  18. Feasibility Study of Odor Biosensor Using Dissociate Neuronal Culture with Gene Expression of Ionotropic Odorant Receptors

    NASA Astrophysics Data System (ADS)

    Tanada, Norio; Sakurai, Takeshi; Mitsuno, Hidefumi; Bakkum, Douglas; Kanzaki, Ryohei; Takahashi, Hirokazu

    We propose a highly sensitive and real-time odor biosensor by expressing ionotropic odorant receptors of insects into dissociated cultures of neurons of rats. The odorant-gated ion channel structure of insect odorant receptor is expected to allow easy functional expression into cells. The neuronal dissociated cultures of rats have two significant advantages: a long lifetime comparable to rats, i.e., a few years; and amplification ability from weak ionic currents of odorant receptors into easily detectable action potentials of neurons. In the present work, in order to show the feasibility of the proposed sensor, we attempt to express the pheromone receptors of silkmoth, Bombyx mori, into cultured neurons of rats. We demonstrate that 10% of neuronal cells transfected using Lipofectamine successfully expressed pheromone receptors, and that these cells showed significant increase of calcium signals by 50% at the presentation of pheromone.

  19. Mathematical model of bursting in dissociated purkinje neurons.

    PubMed

    Forrest, Michael D

    2013-01-01

    In vitro, Purkinje cell behaviour is sometimes studied in a dissociated soma preparation in which the dendritic projection has been cleaved. A fraction of these dissociated somas spontaneously burst. The mechanism of this bursting is incompletely understood. We have constructed a biophysical Purkinje soma model, guided and constrained by experimental reports in the literature, that can replicate the somatically driven bursting pattern and which hypothesises Persistent Na(+) current (INaP) to be its burst initiator and SK K(+) current (ISK) to be its burst terminator.

  20. MDMA, cannabis, and cocaine produce acute dissociative symptoms.

    PubMed

    van Heugten-Van der Kloet, Dalena; Giesbrecht, Timo; van Wel, Janelle; Bosker, Wendy M; Kuypers, Kim P C; Theunissen, Eef L; Spronk, Desirée B; Jan Verkes, Robbert; Merckelbach, Harald; Ramaekers, Johannes G

    2015-08-30

    Some drugs of abuse may produce dissociative symptoms, but this aspect has been understudied. We explored the dissociative potential of three recreational drugs (3,4-methylenedioxymethamphetamine (MDMA), cannabis, and cocaine) during intoxication and compared their effects to literature reports of dissociative states in various samples. Two placebo-controlled studies were conducted. In Study 1 (N=16), participants received single doses of 25, 50, and 100 mg of MDMA, and placebo. In Study 2 (N=21), cannabis (THC 300 µg/kg), cocaine (HCl 300 mg), and placebo were administered. Dissociative symptoms as measured with the Clinician-Administered Dissociative States Scale (CADSS) significantly increased under the influence of MDMA and cannabis. To a lesser extent, this was also true for cocaine. Dissociative symptoms following MDMA and cannabis largely exceeded those observed in schizophrenia patients, were comparable with those observed in Special Forces soldiers undergoing survival training, but were lower compared with ketamine-induced dissociation. Cocaine produced dissociative symptoms that were comparable with those observed in schizophrenia patients, but markedly less than those in Special Forces soldiers and ketamine users. Thus, MDMA and cannabis can produce dissociative symptoms that resemble dissociative pathology. The study of drug induced dissociation is important, because it may shed light on the mechanisms involved in dissociative psychopathology.

  1. Evidence for Cholinergic Synapses Between Dissociated Rat Sympathetic Neurons in Cell Culture

    PubMed Central

    O'Lague, P. H.; Obata, K.; Claude, P.; Furshpan, E. J.; Potter, D. D.

    1974-01-01

    Sympathetic principal neurons were dissociated from superior cervical ganglia of new-born rats, and grown in cell culture. In electrophysiological experiments two types of excitatory synapses were found. One, which was relatively rare, was shown to operate by electrical transmission. The other, the predominant type, had several characteristics of chemical transmission, and pharmacological evidence indicated it was cholinergic. Images PMID:4372629

  2. Acute and Chronic Dissociation and Somatized Anxiety as Related to Childhood Sexual Abuse.

    ERIC Educational Resources Information Center

    Maynes, Lynn C.; Feinauer, Leslie L.

    1994-01-01

    Examined relationship between effects of four sexual abuse variables (identity of perpetrator, frequency of abuse, duration of abuse experiences, and severity of sexual abuse) and survivor symptomatology of acute dissociation, chronic dissociation, and somatized anxiety. Data from 226 respondents showed that severity of sexual abuse experience was…

  3. Resurgent sodium current and action potential formation in dissociated cerebellar Purkinje neurons.

    PubMed

    Raman, I M; Bean, B P

    1997-06-15

    Voltage-dependent sodium channels were studied in dissociated cerebellar Purkinje neurons from rats. In whole-cell recordings, a tetrodotoxin (TTX)-sensitive inward current was elicited when the membrane was repolarized to voltages between -60 and -20 mV after depolarizations to +30 mV long enough to produce maximal inactivation. At -40 mV, this "resurgent" current peaked in 8 msec and decayed with a time constant of 30 msec. With 50 mM sodium as a charge carrier, the resurgent current was on average approximately 120 pA. CA3 pyramidal neurons had no such current. The current may reflect recovery of inactivated channels through open states, because in Purkinje neurons (but not CA3 neurons) there was partial recovery from inactivation at -40 mV, coinciding with the rise of resurgent current. In single-channel recordings, individual channels gave openings corresponding to resurgent and conventional transient current. Action potentials were recorded from dissociated neurons under current clamp to investigate the role of the resurgent current in action potential formation. Purkinje neurons fired spontaneously at approximately 30 Hz. Hyperpolarization to -85 mV prevented spontaneous firing, and brief depolarization then induced all-or-none firing of conglomerate action potentials comprising three to four spikes. When conglomerate action potentials were used as command voltages in voltage-clamp experiments, TTX-sensitive sodium current was elicited between spikes. The falling phase of an action potential is similar to voltage patterns that activate resurgent sodium current, and thus, resurgent sodium current likely contributes to the formation of conglomerate action potentials in Purkinje neurons.

  4. Acute stimulation of transplanted neurons improves motoneuron survival, axon growth, and muscle reinnervation.

    PubMed

    Grumbles, Robert M; Liu, Yang; Thomas, Christie M; Wood, Patrick M; Thomas, Christine K

    2013-06-15

    Few options exist for treatment of pervasive motoneuron death after spinal cord injury or in neurodegenerative diseases such as amyotrophic lateral sclerosis. Local transplantation of embryonic motoneurons into an axotomized peripheral nerve is a promising approach to arrest the atrophy of denervated muscles; however, muscle reinnervation is limited by poor motoneuron survival. The aim of the present study was to test whether acute electrical stimulation of transplanted embryonic neurons promotes motoneuron survival, axon growth, and muscle reinnervation. The sciatic nerve of adult Fischer rats was transected to mimic the widespread denervation seen after disease or injury. Acutely dissociated rat embryonic ventral spinal cord cells were transplanted into the distal tibial nerve stump as a neuron source for muscle reinnervation. Immediately post-transplantation, the cells were stimulated at 20 Hz for 1 h. Other groups were used to control for the cell transplantation and stimulation. When neurons were stimulated acutely, there were significantly more neurons, including cholinergic neurons, 10 weeks after transplantation. This led to enhanced numbers of myelinated axons, reinnervation of more muscle fibers, and more medial and lateral gastrocnemius muscles were functionally connected to the transplant. Reinnervation reduced muscle atrophy significantly. These data support the concept that electrical stimulation rescues transplanted motoneurons and facilitates muscle reinnervation.

  5. Acute peritraumatic dissociation: in favor of a phenomenological inquiry.

    PubMed

    Ataria, Yochai

    2014-01-01

    Fundamental aspects of trauma--among them dissociation during trauma, which is considered one of the strongest predictors of posttraumatic stress disorder-are not fully understood. This article argues that the application of the phenomenological structure of time and the phenomenological description of the self (minimal self, sense of ownership, sense of agency, sense of self) to dissociation during trauma can improve our understanding of this phenomenon-at its occurrence and during any possible ensuing symptoms. In addition, it is argued that the phenomenological approach, as a method that focuses on the bodily level of experience, in particular the body as it is experienced from within, enables us to penetrate the traumatic experience. Thus, by applying the phenomenological approach we may be able to improve our understanding of the traumatic experience and enable the development of better treatment.

  6. Differentiated pattern of sodium channel expression in dissociated Purkinje neurons maintained in long-term culture.

    PubMed

    Fry, Mark; Boegle, Aimee K; Maue, Robert A

    2007-05-01

    Cerebellar Purkinje neurons in vivo exhibit high frequency and multi-spike action potentials with transient (INaT), resurgent (INaR) and persistent (INaP) Na+ currents arising from voltage-gated Na+ channels, which play important roles in shaping the action potentials and electrical activity of these cells. However, little is known about Na+ channel expression in cultured Purkinje neurons despite the use of in vitro approaches to study these cells. Therefore, GFP-expressing Purkinje neurons isolated from transgenic mice were analysed after four weeks in culture, when, coincident with distinct axonal and dendritic morphologies, cultured Purkinje neurons exhibited dendrite-specific MAP2 expression characteristic of polarized neurons. In cell-attached patch clamp recordings, Na+ currents occurred at significantly higher frequencies and amplitudes in patches from the soma and axon than from dendrites, similar to the polarized distribution observed in vivo. INaT, INaR and INaP Na+ currents with properties similar to those observed in acutely isolated Purkinje neurons were detected in nucleated outside-out patches from cultured Purkinje cells. RT-PCR analysis detected Nav1.1, Nav1.2 and Nav1.6, but not Nav1.3, Nav1.4, Nav 1.5 or Nav1.8 Na+ channel alpha subunit gene expression in cultured Purkinje neurons, as observed in vivo. Together, the results indicate that key aspects of Na+ channel expression in mature Purkinje neurons in vivo occur in vitro.

  7. Peritraumatic dissociation mediates the relationship between acute panic and chronic posttraumatic stress disorder.

    PubMed

    Bryant, Richard A; Brooks, Robert; Silove, Derrick; Creamer, Mark; O'Donnell, Meaghan; McFarlane, Alexander C

    2011-05-01

    Although peritraumatic dissociation predicts subsequent posttraumatic stress disorder (PTSD), little is understood about the mechanism of this relationship. This study examines the role of panic during trauma in the relationship between peritraumatic dissociation and subsequent PTSD. Randomized eligible admissions to 4 major trauma hospitals across Australia (n=244) were assessed during hospital admission and within one month of trauma exposure for panic, peritraumatic dissociation and PTSD symptoms, and subsequently re-assessed for PTSD three months after the initial assessment (n=208). Twenty (9.6%) patients met criteria for PTSD at 3-months post injury. Structural equation modeling supported the proposition that peritraumatic derealization (a subset of dissociation) mediated the effect of panic reactions during trauma and subsequent PTSD symptoms. The mediation model indicated that panic reactions are linked to severity of subsequent PTSD via derealization, indicating a significant indirect relationship. Whereas peritraumatic derealization is associated with chronic PTSD symptoms, this relationship is influenced by initial acute panic responses.

  8. Plasticity of hypothalamic dopamine neurons during lactation results in dissociation of electrical activity and release.

    PubMed

    Romanò, Nicola; Yip, Siew H; Hodson, David J; Guillou, Anne; Parnaudeau, Sébastien; Kirk, Siobhan; Tronche, François; Bonnefont, Xavier; Le Tissier, Paul; Bunn, Stephen J; Grattan, Dave R; Mollard, Patrice; Martin, Agnès O

    2013-03-06

    Tuberoinfundibular dopamine (TIDA) neurons are the central regulators of prolactin (PRL) secretion. Their extensive functional plasticity allows a change from low PRL secretion in the non-pregnant state to the condition of hyperprolactinemia that characterizes lactation. To allow this rise in PRL, TIDA neurons are thought to become unresponsive to PRL at lactation and functionally silenced. Here we show that, contrary to expectations, the electrical properties of the system were not modified during lactation and that the neurons remained electrically responsive to a PRL stimulus, with PRL inducing an acute increase in their firing rate during lactation that was identical to that seen in non-pregnant mice. Furthermore, we show a long-term organization of TIDA neuron electrical activity with an harmonization of their firing rates, which remains intact during lactation. However, PRL-induced secretion of dopamine (DA) at the median eminence was strongly blunted during lactation, at least in part attributable to lack of phosphorylation of tyrosine hydroxylase, the key enzyme involved in DA synthesis. We therefore conclude that lactation, rather than involving electrical silencing of TIDA neurons, represents a condition of decoupling between electrical activity at the cell body and DA secretion at the median eminence.

  9. Iridium oxide microelectrode arrays for in vitro stimulation of individual rat neurons from dissociated cultures.

    PubMed

    Eick, Stefan; Wallys, Jens; Hofmann, Boris; van Ooyen, André; Schnakenberg, Uwe; Ingebrandt, Sven; Offenhäusser, Andreas

    2009-01-01

    We present the first in vitro extracellular stimulation of individual neurons from dissociated cultures with iridium oxide (IrO(x)) electrodes. Microelectrode arrays with sputtered IrO(x) films (SIROF) were developed for electrophysiological investigations with electrogenic cells. The microelectrodes were characterized with scanning electron and atomic force microscopy, revealing rough and porous electrodes with enlarged surface areas. As shown by cyclic voltammetry and electrochemical impedance spectroscopy, the large surface area in combination with the good electrochemical properties of SIROF resulted in high charge storage capacity and low electrode impedance. Thus, we could transfer the good properties of IrO(x) as material for in vivo stimulation electrodes to multi-electrode arrays with electrode diameters as small as 10 mum for in vitro applications. Single rat cortical neurons from dissociated cultures were successfully stimulated to fire action potentials using single or trains of biphasic rectangular voltage-controlled stimulation pulses. The stimulated cell's membrane potential was simultaneously monitored using whole-cell current-clamp recordings. This experimental configuration allowed direct evaluation of the influence of pulse phase sequence, amplitude, and number on the stimulation success ratio and action potential latency. Negative phase first pulses were more effective for extracellular stimulation and caused reduced latency in comparison to positive phase first pulses. Increasing the pulse amplitude also improved stimulation reliability. However, in order to prevent cell or electrode damage, the pulse amplitude is limited to voltages below the threshold for irreversible electrochemical reactions at the electrode. As an alternative to increasing the amplitude, a higher number of stimulation pulses was also shown to increase stimulation success.

  10. Iridium Oxide Microelectrode Arrays for In Vitro Stimulation of Individual Rat Neurons from Dissociated Cultures

    PubMed Central

    Eick, Stefan; Wallys, Jens; Hofmann, Boris; van Ooyen, André; Schnakenberg, Uwe; Ingebrandt, Sven; Offenhäusser, Andreas

    2009-01-01

    We present the first in vitro extracellular stimulation of individual neurons from dissociated cultures with iridium oxide (IrOx) electrodes. Microelectrode arrays with sputtered IrOx films (SIROF) were developed for electrophysiological investigations with electrogenic cells. The microelectrodes were characterized with scanning electron and atomic force microscopy, revealing rough and porous electrodes with enlarged surface areas. As shown by cyclic voltammetry and electrochemical impedance spectroscopy, the large surface area in combination with the good electrochemical properties of SIROF resulted in high charge storage capacity and low electrode impedance. Thus, we could transfer the good properties of IrOx as material for in vivo stimulation electrodes to multi-electrode arrays with electrode diameters as small as 10 μm for in vitro applications. Single rat cortical neurons from dissociated cultures were successfully stimulated to fire action potentials using single or trains of biphasic rectangular voltage-controlled stimulation pulses. The stimulated cell's membrane potential was simultaneously monitored using whole-cell current-clamp recordings. This experimental configuration allowed direct evaluation of the influence of pulse phase sequence, amplitude, and number on the stimulation success ratio and action potential latency. Negative phase first pulses were more effective for extracellular stimulation and caused reduced latency in comparison to positive phase first pulses. Increasing the pulse amplitude also improved stimulation reliability. However, in order to prevent cell or electrode damage, the pulse amplitude is limited to voltages below the threshold for irreversible electrochemical reactions at the electrode. As an alternative to increasing the amplitude, a higher number of stimulation pulses was also shown to increase stimulation success. PMID:19949459

  11. Effects of 1,8-cineole on Na(+) currents of dissociated superior cervical ganglia neurons.

    PubMed

    Ferreira-da-Silva, Francisco Walber; da Silva-Alves, Kerly Shamyra; Alves-Fernandes, Thaís Antônia; Coelho-de-Souza, Andrelina Noronha; Leal-Cardoso, José Henrique

    2015-05-19

    1,8-Cineole is a terpenoid present in many essential oil of plants with several pharmacological and biological effects, including antinociceptive, smooth muscle relaxant and ion channel activation. Also, 1,8-cineole blocked action potentials, reducing excitability of peripheral neurons. The objective of this work was to investigate effects of 1,8-cineole on Na(+) currents (INa(+)) in dissociated superior cervical ganglion neurons (SCG). Wistar rats of both sexes were used (10-12 weeks old, 200-300g). SCG's were dissected and neurons were enzymatically treated. To study 1,8-cineole effect on INa(+), the patch-clamp technique in whole-cell mode was employed. 1,8-Cineole (6.0mM) partially blocked INa(+) in SCG neurons. The effect stabilized within ∼150s and there was a partial recovery of INa(+) after washout. Current density was reduced from -105.8 to -83.7pA/pF, corresponding to a decrease to ∼20% of control. 1,8-Cineole also reduced the time-to-peak of INa(+) activation and the amplitude and decay time constants of INa(+) inactivation. Current-voltage plots revealed that 1,8-cineole left-shifted the V1/2 of both activation and inactivation curves by ∼10 and ∼20mV, respectively. In conclusion, we demonstrate that 1,8-cineole directly affects Na(+) channels of the SCG by modifying several gating parameters that are likely to be the major cause of excitability blockade.

  12. Assessing DSM-5 latent subtypes of acute stress disorder dissociative or intrusive?

    PubMed

    Armour, Cherie; Hansen, Maj

    2015-02-28

    Acute Stress Disorder (ASD) was first included in the DSM-IV in 1994. It was proposed to account for traumatic responding in the early post trauma phase and to act as an identifier for later Posttraumatic Stress Disorder (PTSD). Unlike PTSD it included a number of dissociative indicators. The revised DSM-5 PTSD criterion included a dissociative-PTSD subtype. The current study assessed if a dissociative-ASD subtype may be present for DSM-5 ASD. Moreover, we assessed if a number of risk factors resulted in an increased probability of membership in symptomatic compared to a baseline ASD profile. We used data from 450 bank robbery victims. Latent profile analysis (LPA) was used to uncover latent profiles of ASD. Multinomial logistic regression was used to determine if female gender, age, social support, peritraumatic panic, somatization, and number of trauma exposures increased or decreased the probability of profile membership. Four latent profiles were uncovered and included an intrusion rather than dissociative subtype. Increased age and social support decreased the probability of individuals being grouped into the intrusion subtype whereas increased peritraumatic panic and somatization increased the probability of individuals being grouped into the intrusion subtype. Findings are discussed in regard to the ICD-11 and the DSM-5.

  13. Acute coronal plane scaphoid fracture and scapholunate dissociation from an axial load: a case report.

    PubMed

    Shin, Alexander Y; Horton, Todd; Bishop, Allen T

    2005-03-01

    Coronal fractures of the scaphoid are rare and can be difficult to diagnose. Axial load injuries that result in a complete coronal fracture of the scaphoid associated with an acute scapholunate dissociation are exceedingly rare. In our patient the radiographic finding of wide scapholunate dissociation was obvious; however, the coronal scaphoid fracture was not recognized initially nor suspected. During surgery the coronal scaphoid fracture was identified, reduced anatomically, and fixed with a compression screw. The scapholunate ligament also was repaired. A good result was obtained with return to sports with extension of 60 degrees and flexion of 70 degrees , grip strength equal to that of the uninjured wrist, and no radiographic problems (arthrosis, avascular necrosis, nonunion).

  14. Effects of acute spinalization on neurons of postural networks

    PubMed Central

    Zelenin, Pavel V.; Lyalka, Vladimir F.; Hsu, Li-Ju; Orlovsky, Grigori N.; Deliagina, Tatiana G.

    2016-01-01

    Postural limb reflexes (PLRs) represent a substantial component of postural corrections. Spinalization results in loss of postural functions, including disappearance of PLRs. The aim of the present study was to characterize the effects of acute spinalization on two populations of spinal neurons (F and E) mediating PLRs, which we characterized previously. For this purpose, in decerebrate rabbits spinalized at T12, responses of interneurons from L5 to stimulation causing PLRs before spinalization, were recorded. The results were compared to control data obtained in our previous study. We found that spinalization affected the distribution of F- and E-neurons across the spinal grey matter, caused a significant decrease in their activity, as well as disturbances in processing of posture-related sensory inputs. A two-fold decrease in the proportion of F-neurons in the intermediate grey matter was observed. Location of populations of F- and E-neurons exhibiting significant decrease in their activity was determined. A dramatic decrease of the efficacy of sensory input from the ipsilateral limb to F-neurons, and from the contralateral limb to E-neurons was found. These changes in operation of postural networks underlie the loss of postural control after spinalization, and represent a starting point for the development of spasticity. PMID:27302149

  15. Neuronal mechanism for acute mechanosensitivity in tactile-foraging waterfowl

    PubMed Central

    Schneider, Eve R.; Mastrotto, Marco; Laursen, Willem J.; Schulz, Vincent P.; Goodman, Jena B.; Funk, Owen H.; Gallagher, Patrick G.; Gracheva, Elena O.; Bagriantsev, Sviatoslav N.

    2014-01-01

    Relying almost exclusively on their acute sense of touch, tactile-foraging birds can feed in murky water, but the cellular mechanism is unknown. Mechanical stimuli activate specialized cutaneous end organs in the bill, innervated by trigeminal afferents. We report that trigeminal ganglia (TG) of domestic and wild tactile-foraging ducks exhibit numerical expansion of large-diameter mechanoreceptive neurons expressing the mechano-gated ion channel Piezo2. These features are not found in visually foraging birds. Moreover, in the duck, the expansion of mechanoreceptors occurs at the expense of thermosensors. Direct mechanical stimulation of duck TG neurons evokes high-amplitude depolarizing current with a low threshold of activation, high signal amplification gain, and slow kinetics of inactivation. Together, these factors contribute to efficient conversion of light mechanical stimuli into neuronal excitation. Our results reveal an evolutionary strategy to hone tactile perception in vertebrates at the level of primary afferents. PMID:25246547

  16. Distinct effects of Abelson kinase mutations on myocytes and neurons in dissociated Drosophila embryonic cultures: mimicking of high temperature.

    PubMed

    Liu, Lijuan; Wu, Chun-Fang

    2014-01-01

    Abelson tyrosine kinase (Abl) is known to regulate axon guidance, muscle development, and cell-cell interaction in vivo. The Drosophila primary culture system offers advantages in exploring the cellular mechanisms mediated by Abl with utilizing various experimental manipulations. Here we demonstrate that single-embryo cultures exhibit stage-dependent characteristics of cellular differentiation and developmental progression in neurons and myocytes, as well as nerve-muscle contacts. In particular, muscle development critically depends on the stage of dissociated embryos. In wild-type (WT) cultures derived from embryos before stage 12, muscle cells remained within cell clusters and were rarely detected. Interestingly, abundant myocytes were spotted in Abl mutant cultures, exhibiting enhanced myocyte movement and fusion, as well as neuron-muscle contacts even in cultures dissociated from younger, stage 10 embryos. Notably, Abl myocytes frequently displayed well-expanded lamellipodia. Conversely, Abl neurons were characterized with fewer large veil-like lamellipodia, but instead had increased numbers of filopodia and darker nodes along neurites. These distinct phenotypes were equally evident in both homo- and hetero-zygous cultures (Abl/Abl vs. Abl/+) of different alleles (Abl(1) and Abl(4) ) indicating dominant mutational effects. Strikingly, in WT cultures derived from stage 10 embryos, high temperature (HT) incubation promoted muscle migration and fusion, partially mimicking the advanced muscle development typical of Abl cultures. However, HT enhanced neuronal growth with increased numbers of enlarged lamellipodia, distinct from the characteristic Abl neuronal morphology. Intriguingly, HT incubation also promoted Abl lamellipodia expansion, with a much greater effect on nerve cells than muscle. Our results suggest that Abl is an essential regulator for myocyte and neuron development and that high-temperature incubation partially mimics the faster muscle development

  17. Acute ethanol suppresses glutamatergic neurotransmission through endocannabinoids in hippocampal neurons.

    PubMed

    Basavarajappa, Balapal S; Ninan, Ipe; Arancio, Ottavio

    2008-11-01

    Ethanol exposure during fetal development is a leading cause of long-term cognitive impairments. Studies suggest that ethanol exposure have deleterious effects on the hippocampus, a brain region that is important for learning and memory. Ethanol exerts its effects, in part, via alterations in glutamatergic neurotransmission, which is critical for the maturation of neuronal circuits during development. The current literature strongly supports the growing evidence that ethanol inhibits glutamate release in the neonatal CA1 hippocampal region. However, the exact molecular mechanism responsible for this effect is not well understood. In this study, we show that ethanol enhances endocannabinoid (EC) levels in cultured hippocampal neurons, possibly through calcium pathways. Acute ethanol depresses miniature post-synaptic current (mEPSC) frequencies without affecting their amplitude. This suggests that ethanol inhibits glutamate release. The CB1 receptors (CB1Rs) present on pre-synaptic neurons are not altered by acute ethanol. The CB1R antagonist SR 141716A reverses ethanol-induced depression of mEPSC frequency. Drugs that are known to enhance the in vivo function of ECs occlude ethanol effects on mEPSC frequency. Chelation of post-synaptic calcium by EGTA antagonizes ethanol-induced depression of mEPSC frequency. The activation of CB1R with the selective agonist WIN55,212-2 also suppresses the mEPSC frequency. This WIN55,212-2 effect is similar to the ethanol effects and is reversed by SR141716A. In addition, tetani-induced excitatory post-synaptic currents (EPSCs) are depressed by acute ethanol. SR141716A significantly reverses ethanol effects on evoked EPSC amplitude in a dual recording preparation. These observations, taken together, suggest the participation of ECs as retrograde messengers in the ethanol-induced depression of synaptic activities.

  18. Functional dissociation in sweet taste receptor neurons between and within taste organs of Drosophila

    PubMed Central

    Thoma, Vladimiros; Knapek, Stephan; Arai, Shogo; Hartl, Marion; Kohsaka, Hiroshi; Sirigrivatanawong, Pudith; Abe, Ayako; Hashimoto, Koichi; Tanimoto, Hiromu

    2016-01-01

    Finding food sources is essential for survival. Insects detect nutrients with external taste receptor neurons. Drosophila possesses multiple taste organs that are distributed throughout its body. However, the role of different taste organs in feeding remains poorly understood. By blocking subsets of sweet taste receptor neurons, we show that receptor neurons in the legs are required for immediate sugar choice. Furthermore, we identify two anatomically distinct classes of sweet taste receptor neurons in the leg. The axonal projections of one class terminate in the thoracic ganglia, whereas the other projects directly to the brain. These two classes are functionally distinct: the brain-projecting neurons are involved in feeding initiation, whereas the thoracic ganglia-projecting neurons play a role in sugar-dependent suppression of locomotion. Distinct receptor neurons for the same taste quality may coordinate early appetitive responses, taking advantage of the legs as the first appendages to contact food. PMID:26893070

  19. Acute dissociative reaction to spontaneous delivery in a case of total denial of pregnancy: Diagnostic and forensic aspects.

    PubMed

    Şar, Vedat; Aydın, Nazan; van der Hart, Onno; Steven Frankel, A; Şar, Meriç; Omay, Oğuz

    2016-12-20

    This article presents the history of a 21-year-old female college student with total denial of pregnancy who experienced an acute dissociative reaction during the spontaneous delivery at home without medical assistance where the newborn died immediately. Psychiatric examination, self-report questionnaires, legal documents, and witness reports have been reviewed in evaluation of the case. Evidence pointed to total denial of pregnancy, that is, until delivery. The diagnoses of an acute dissociative reaction to stress (remitted) and a subsequent PTSD were established in a follow-up examination conducted 7 months after the delivery. Notwithstanding the inherently dissociative nature of total denial of pregnancy, no other evidence has been found about pre-existing psychopathology. For causing the newborn's death, the patient faced charges for "aggravated murder," which were later on reduced into "involuntary manslaughter." Given the physical incapacity to perform voluntary acts due to the loss of control over her actions during the delivery, and the presence of an acute dissociative reaction to unexpected delivery, the legal case represents an intricate overlap between "insanity" and "incapacitation" defenses. The rather broad severity spectrum of acute dissociative conditions requires evaluation of the limits and conditions of appropriate legal defenses by mental health experts and lawyers. Denial of pregnancy as a source of potential stress has attracted little interest in psychiatric literature although solid research exists which documented that it is not infrequent. Arguments are presented to introduce this condition as a diagnostic category of female reproductive psychiatry with a more neutral label: "unperceived pregnancy."

  20. Acute effects of ACTH on dissociated adrenocortical cells: quantitative changes in mitochondria and lipid droplets.

    PubMed

    Zoller, L C; Malamed, S

    1975-08-01

    To study the role of certain organelles in steroidogenesis, dissociated rat adrenocortical cells were incubated for two hours with ACTH at a concentration that induces a high level of steroid production. Sections of ACTH treated and untreated cells were photographed in the electron microscope, and morphometric analysis was undertaken to assess possible ACTH-induced changes in total cell volume, volume density and numerical denisty of lipid droplets and mitochondria. There was no change in total cell volume. Lipid droplet volume density and numerical density decreased. Mitochondrial volume density did not change, but numerical density increased. The decrease in lipid droplet volume density indicates a rapid depletion of cholesterol for steroid production. This depletion is almost entirely due to the disappearance of lipid droplets, rather than to an overall diminution in their size, as shown by the decrease in lipid droplet numerical density. The mitochondrial data suggest that the adrenocortical cell has an adedquate mitochondrial apparatus to respond to acute ACTH stimulation with increased steroid output without an increase inmitochondrial volume.

  1. Neuronal activity mediated regulation of glutamate transporter GLT‐1 surface diffusion in rat astrocytes in dissociated and slice cultures

    PubMed Central

    Al Awabdh, Sana; Gupta‐Agarwal, Swati; Sheehan, David F.; Muir, James; Norkett, Rosalind; Twelvetrees, Alison E.; Griffin, Lewis D.

    2016-01-01

    The astrocytic GLT‐1 (or EAAT2) is the major glutamate transporter for clearing synaptic glutamate. While the diffusion dynamics of neurotransmitter receptors at the neuronal surface are well understood, far less is known regarding the surface trafficking of transporters in subcellular domains of the astrocyte membrane. Here, we have used live‐cell imaging to study the mechanisms regulating GLT‐1 surface diffusion in astrocytes in dissociated and brain slice cultures. Using GFP‐time lapse imaging, we show that GLT‐1 forms stable clusters that are dispersed rapidly and reversibly upon glutamate treatment in a transporter activity‐dependent manner. Fluorescence recovery after photobleaching and single particle tracking using quantum dots revealed that clustered GLT‐1 is more stable than diffuse GLT‐1 and that glutamate increases GLT‐1 surface diffusion in the astrocyte membrane. Interestingly, the two main GLT‐1 isoforms expressed in the brain, GLT‐1a and GLT‐1b, are both found to be stabilized opposed to synapses under basal conditions, with GLT‐1b more so. GLT‐1 surface mobility is increased in proximity to activated synapses and alterations of neuronal activity can bidirectionally modulate the dynamics of both GLT‐1 isoforms. Altogether, these data reveal that astrocytic GLT‐1 surface mobility, via its transport activity, is modulated during neuronal firing, which may be a key process for shaping glutamate clearance and glutamatergic synaptic transmission. GLIA 2016;64:1252–1264 PMID:27189737

  2. APP as a Protective Factor in Acute Neuronal Insults

    PubMed Central

    Hefter, Dimitri; Draguhn, Andreas

    2017-01-01

    Despite its key role in the molecular pathology of Alzheimer’s disease (AD), the physiological function of amyloid precursor protein (APP) is unknown. Increasing evidence, however, points towards a neuroprotective role of this membrane protein in situations of metabolic stress. A key observation is the up-regulation of APP following acute (stroke, cardiac arrest) or chronic (cerebrovascular disease) hypoxic-ischemic conditions. While this mechanism may increase the risk or severity of AD, APP by itself or its soluble extracellular fragment APPsα can promote neuronal survival. Indeed, different animal models of acute hypoxia-ischemia, traumatic brain injury (TBI) and excitotoxicity have revealed protective effects of APP or APPsα. The underlying mechanisms involve APP-mediated regulation of calcium homeostasis via NMDA receptors (NMDAR), voltage-gated calcium channels (VGCC) or internal calcium stores. In addition, APP affects the expression of survival- or apoptosis-related genes as well as neurotrophic factors. In this review, we summarize the current understanding of the neuroprotective role of APP and APPsα and possible implications for future research and new therapeutic strategies. PMID:28210211

  3. [Responses of neurons of the associative parietal cortex during acute extinction restoration of a conditioned reflex].

    PubMed

    Prikhodchenko, N N

    1977-01-01

    The dynamics of spike neuronal activity in the parietal associative cortex was studied in the course of acute extinction and restoration of a conditioned reflex. Certain similarities have been found in neuronal firing during the reorganization of behavioral acts (transient processes in neuronal activity, general types of neuronal responses, etc.) The data obtained suggest the involvement of neurones of the parietal associative cortex in the processes related to the reorganization of behavioral acts, and the existence of common mechanisms of search for an optimal regime of neuronal assemblies functioning in different types of conditioned activity.

  4. Sleep active cortical neurons expressing neuronal nitric oxide synthase are active after both acute sleep deprivation and chronic sleep restriction.

    PubMed

    Zielinski, M R; Kim, Y; Karpova, S A; Winston, S; McCarley, R W; Strecker, R E; Gerashchenko, D

    2013-09-05

    Non-rapid eye movement (NREM) sleep electroencephalographic (EEG) delta power (~0.5-4 Hz), also known as slow wave activity (SWA), is typically enhanced after acute sleep deprivation (SD) but not after chronic sleep restriction (CSR). Recently, sleep-active cortical neurons expressing neuronal nitric oxide synthase (nNOS) were identified and associated with enhanced SWA after short acute bouts of SD (i.e., 6h). However, the relationship between cortical nNOS neuronal activity and SWA during CSR is unknown. We compared the activity of cortical neurons expressing nNOS (via c-Fos and nNOS immuno-reactivity, respectively) and sleep in rats in three conditions: (1) after 18-h of acute SD; (2) after five consecutive days of sleep restriction (SR) (18-h SD per day with 6h ad libitum sleep opportunity per day); (3) and time-of-day matched ad libitum sleep controls. Cortical nNOS neuronal activity was enhanced during sleep after both 18-h SD and 5 days of SR treatments compared to control treatments. SWA and NREM sleep delta energy (the product of NREM sleep duration and SWA) were positively correlated with enhanced cortical nNOS neuronal activity after 18-h SD but not 5days of SR. That neurons expressing nNOS were active after longer amounts of acute SD (18h vs. 6h reported in the literature) and were correlated with SWA further suggest that these cells might regulate SWA. However, since these neurons were active after CSR when SWA was not enhanced, these findings suggest that mechanisms downstream of their activation are altered during CSR.

  5. Caffeine and related compounds block inhibitory amino acid-gated Cl- currents in freshly dissociated rat hippocampal neurones.

    PubMed Central

    Uneyama, H.; Harata, N.; Akaike, N.

    1993-01-01

    1. The effects of caffeine and related compounds on responses mediated by inhibitory amino acids were investigated in freshly dissociated rat hippocampal pyramidal neurones by conventional and nystatin perforated patch-clamp techniques. 2. Glycine and gamma-aminobutyric acid (GABA) evoked Cl- currents in hippocampal neurones. The half-maximum effective concentrations (EC50) of glycine and GABA were 8.5 x 10(-5) and 5 x 10(-6) M, respectively. 3. Caffeine reversibly inhibited both 10(-4) M glycine- and 10(-5) M GABA-induced Cl-currents in a concentration-dependent manner. The half-maximum inhibitory concentrations (IC50) of caffeine were 4.5 x 10(-4) M for the glycine response and 3.6 x 10(-3) M for the GABA response. 4. Caffeine shifted the concentration-response curve of IGly to the right without affecting the maximum response. 5. The inhibitory action of caffeine did not show voltage-dependency. 6. The blocking action of caffeine was not affected by intracellular perfusion with 5 mM BAPTA or by pretreatment with the protein kinase A inhibitor, H-8. This excludes the participation of Ca2+ or cyclic AMP in the inhibitory action of caffeine. 7. Caffeine failed to inhibit the augmentations of aspartate- and N-methyl-D-aspartate (NMDA) -gated current by glycine, suggesting that caffeine has no effect on the allosteric glycine binding site on the NMDA receptor. 8. The inhibitory effects of some xanthine derivatives on IGly were compared. The inhibitory potency of those compounds on IGly was in the order of pentoxifylline > theophylline > or = caffeine > paraxanthine > IBMX > or = theobromine > dyphylline. Xanthine had no effect.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7689394

  6. Differential time-course of slow afterhyperpolarizations and associated Ca2+ transients in rat CA1 pyramidal neurons: further dissociation by Ca2+ buffer.

    PubMed

    Jahromi, B S; Zhang, L; Carlen, P L; Pennefather, P

    1999-01-01

    Hippocampal neurons exhibit a slow afterhyperpolarization following membrane depolarization; this is thought to reflect an underlying Ca2+-dependent K+ current. This current is potentiated by intermediate concentrations (0.1-1.0 mM) of exogenous Ca2+ buffer [Schwindt P. C. et al. (1992) Neuroscience 47, 571-578; Zhang L. et al. (1995) J. Neurophysiol. 74, 2225-2241]. The relationship between the slow afterhyperpolarization and associated Ca2+ transients was investigated in the presence and absence of added exogenous Ca2+ buffer. Slow afterhyperpolarizations and underlying K+ currents were measured using whole-cell patch-clamp recordings from hippocampal CA1 neurons in acute rat brain slices. Inclusion of fluorescent Ca2+ indicators in the patch pipette solution allowed simultaneous measurement of the evoked subcellular Ca2+ transients using a confocal microscope. The peak Ca2+ signal exhibited an incremental increase with each action potential. This increase eventually reached a plateau with increasing numbers of action potentials, suggesting dye saturation with peak Ca2+ concentrations. As the K(D) for Ca2+ of the indicator dyes used was between 200 and 300 nM, it is predicted that saturation will occur when the peak Ca2+ signal exceeds 1 microM. This occurred with fewer action potentials in dendritic vs somatic compartments. Neither compartment exhibited averaged Ca2+ transients matching the slow afterhyperpolarization time-course, dendritic Ca2+ transients being most divergent. Intracellular accumulation of exogenous Ca2+ buffer, either by inclusion in the patch pipette or by incubation of the brain slice with its membrane-permeable form, caused a prolongation of the slow afterhyperpolarization but not of the somatic Ca2+ transient. The initial rate of decline of the dendritic Ca2+ transient was diminished, but remained faster than that of the slow afterhyperpolarization. We conclude that neither dendritic nor somatic Ca2+ signals match the slow

  7. Evaluation of the importance of astrocytes when screening for acute toxicity in neuronal cell systems.

    PubMed

    Woehrling, E K; Hill, E J; Coleman, M D

    2010-02-01

    Reliable, high throughput, in vitro preliminary screening batteries have the potential to greatly accelerate the rate at which regulatory neurotoxicity data is generated. This study evaluated the importance of astrocytes when predicting acute toxic potential using a neuronal screening battery of pure neuronal (NT2.N) and astrocytic (NT2.A) and integrated neuronal/astrocytic (NT2.N/A) cell systems derived from the human NT2.D1 cell line, using biochemical endpoints (mitochondrial membrane potential (MMP) depolarisation and ATP and GSH depletion). Following exposure for 72 h, the known acute human neurotoxicants trimethyltin-chloride, chloroquine and 6-hydroxydopamine were frequently capable of disrupting biochemical processes in all of the cell systems at non-cytotoxic concentrations. Astrocytes provide key metabolic and protective support to neurons during toxic challenge in vivo and generally the astrocyte containing cell systems showed increased tolerance to toxicant insult compared with the NT2.N mono-culture in vitro. Whilst there was no consistent relationship between MMP, ATP and GSH log IC(50) values for the NT2.N/A and NT2.A cell systems, these data did provide preliminary evidence of modulation of the acute neuronal toxic response by astrocytes. In conclusion, the suitability of NT2 neurons and astrocytes as cell systems for acute toxicity screening deserves further investigation.

  8. Prefrontal cortex gates acute morphine action on dopamine neurons in the ventral tegmental area.

    PubMed

    Liu, Changliang; Fang, Xing; Wu, Qianqian; Jin, Guozhang; Zhen, Xuechu

    2015-08-01

    Morphine excites dopamine (DA) neurons in the ventral tegmental area (VTA), an effect mediated by both local and systemic mechanisms. While the importance of the prefrontal cortex (PFC) - VTA circuit in opiate addiction is well established, little is known about how the PFC regulates the activity of VTA DA neurons upon morphine stimulation. One major challenge is that VTA DA neurons are highly heterogeneous in terms of projection and regulation, making their responses to PFC manipulations variable. Our previous work has identified a subgroup of VTA DA neurons exhibiting significant slow oscillation in their firing sequence, and demonstrated that most of these neurons are functionally connected with the PFC. In the present study, we focus our efforts only on VTA DA neurons expressing strong slow oscillation, and report that blocking the neuronal activity in the PFC remarkably attenuates the morphine-induced excitation of these neurons. Using in vivo microdialysis, we find that inactivation of the PFC also reduces the morphine-induced elevation of DA levels in the nucleus accumbens (NAc). Furthermore, 24 h after only single morphine exposure, PFC-inactivation failed to prevent subsequent morphine challenge from exciting VTA DA neurons, which is paralleled by altered response of PFC pyramidal neurons to morphine stimulation. Our results indicate that the PFC gates acute morphine action on a subset of VTA DA neurons, which is highly plastic and can be functionally remodeled by morphine exposure.

  9. Effect of acute lateral hemisection of the spinal cord on spinal neurons of postural networks.

    PubMed

    Zelenin, P V; Lyalka, V F; Orlovsky, G N; Deliagina, T G

    2016-12-17

    In quadrupeds, acute lateral hemisection of the spinal cord (LHS) severely impairs postural functions, which recover over time. Postural limb reflexes (PLRs) represent a substantial component of postural corrections in intact animals. The aim of the present study was to characterize the effects of acute LHS on two populations of spinal neurons (F and E) mediating PLRs. For this purpose, in decerebrate rabbits, responses of individual neurons from L5 to stimulation causing PLRs were recorded before and during reversible LHS (caused by temporal cold block of signal transmission in lateral spinal pathways at L1), as well as after acute surgical LHS at L1. Results obtained after Sur-LHS were compared to control data obtained in our previous study. We found that acute LHS caused disappearance of PLRs on the affected side. It also changed a proportion of different types of neurons on that side. A significant decrease and increase in the proportion of F- and non-modulated neurons, respectively, was found. LHS caused a significant decrease in most parameters of activity in F-neurons located in the ventral horn on the lesioned side and in E-neurons of the dorsal horn on both sides. These changes were caused by a significant decrease in the efficacy of posture-related sensory input from the ipsilateral limb to F-neurons, and from the contralateral limb to both F- and E-neurons. These distortions in operation of postural networks underlie the impairment of postural control after acute LHS, and represent a starting point for the subsequent recovery of postural functions.

  10. Regulation of K+ conductance by histamine H1 and H2 receptors in neurones dissociated from rat neostriatum.

    PubMed

    Munakata, M; Akaike, N

    1994-10-15

    1. The effects of histamine on dissociated neostriatal neurones of the rat were investigated in the whole-cell mode using the nystatin-perforated patch recording technique. 2. Histamine evoked a net inward current accompanied by a decrease in the membrane conductance at a holding potential (Vh) of -44 mV. This response was observed in neurones considered to be interneurones based on morphology, membrane properties and the responsiveness to acetylcholine. 3. A net inward current evoked by 10(-8) to 10(-6) M histamine was inhibited in a concentration-dependent manner by the H1 receptor antagonists, pyrilamine and triprolidine. The H1 receptor agonists, 2-methylhistamine and 2-thiazolylethylamine, mimicked the histamine response, indicating that this response was mediated by the H1 receptor. 4. Histamine, at high concentrations between 10(-6) and 10(-5) M, evoked an additional net inward current with a decrease in the membrane conductance, which was inhibited by the H2 receptor antagonists, cimetidine, ranitidine and famotidine. The H2 receptor agonist, impromidine, partially mimicked the response. Thus, this additional current was considered to be mediated by the H2 receptor. 5. The reversal potentials for H1 and H2 receptor-operated currents shifted 56.9 and 59.3 mV for a 10-fold change in [K+]o, respectively, suggesting that these currents were carried by K+. 6. An analysis of change in current fluctuations mediated by H1 and H2 receptors suggested that the unitary current amplitudes of K+ channels linked to H1 and H2 receptors were 0.29 +/- 0.06 (n = 4) and 0.27 +/- 0.07 pA (n = 4), respectively. There was no significant difference between these values. The estimated mean life times (tau) for both channels were also identical (1.1 ms). 7. It was concluded that histamine reduces K+ currents in neostriatal interneurones and that both H1 and H2 receptors are involved in the response.

  11. Brain neuronal chromatin responses in acute soman intoxicated rats.

    PubMed

    Martin, L J; Doebler, J A; Wall, T J; Shih, T M; Anthony, A

    1986-08-01

    Male Sprague-Dawley rats (200 g) were injected subcutaneously with soman, a potent neuronal acetylcholinesterase (AChE) inhibitor, at doses of 0.5, 0.8 and 1.0 LD50 (1 LD50 = 135 micrograms/kg) before decapitation at 1 and 24 h post-exposure. Correlative data were obtained on the severity of brain AChE inactivation and physicochemical changes in nuclear chromatin of cerebrocortical (layer V) and striatal neurons using Feulgen-DNA (F-DNA) cytophotometry and ocular filar micrometry. Decreased lability of neurons to F-DNA acid hydrolysis (reduced F-DNA yield), nuclear shrinkage and chromatin aggregation (decreased chromophore area) were used as indices of suppression of genomic template activity; conversely, increases in F-DNA yield and chromophore area signify enhanced neuroexcitation. At 1 hr post-soman there was a dose-dependent inactivation of AChE with a moderate increase in chromatin activation, i.e., nuclear hypertrophy and chromatin dispersion. At 24 hr post-soman there was a partial restoration of AChE activity, notably in striatal neurons, with a suppression in chromatin template activity. These data indicate that actions of soman on neuronal functioning are time-dependent. The absence of any dose-related neuronal chromatin changes may signify existence of non-cholinergic mediated events.

  12. Acute effect of exposure of mollusk single neuron to 900-MHz mobile phone radiation.

    PubMed

    Partsvania, B; Sulaberidze, T; Shoshiashvili, L; Modebadze, Z

    2011-09-01

    The goal of the present work was to explore the influence of commercially available cell phone irradiation on the single neuron excitability and memory processes. A Transverse Electromagnetic Cell (TEM Cell) was used to expose single neurons of mollusk to the electromagnetic field. Finite-Difference Time-Domain (FDTD) method was used for modeling the TEM Cell and the electromagnetic field interactions with living nerve ganglion and neurons. Neuron electrophysiology was investigated using standard microelectrode technique. The specific absorption rate (SAR) deposited into the single neuron was calculated to be 0.63 W/kg with a temperature increment of 0.1°C. After acute exposure, average firing threshold of the action potentials was not changed. However, the average latent period was significantly decreased. This indicates that together with latent period the threshold and the time of habituation might be altered during exposure. However, these alterations are transient and only latent period remains on the changed level.

  13. Properties of native P2X receptors in large multipolar neurons dissociated from rat hypothalamic arcuate nucleus.

    PubMed

    Wakamori, Minoru; Sorimachi, Masaru

    2004-04-16

    ATP, the ligand of P2X receptors, is a candidate of neurotransmitter or co-transmitter in the peripheral and the central nervous systems. Anatomical studies have revealed the wide distribution of P2X receptors in the brain. So far, P2X-mediated small synaptic responses have been recorded in some brain regions. To determine the physiological significance of postsynaptic ATP receptors in the brain, we have investigated the P2X responses in rat dissociated hypothalamic arcuate neurons by using the patch-clamp technique. ATP evoked inward currents in a concentration-dependent manner (EC(50)=42 microM) at a holding potential of -70 mV. The current-voltage relationship showed a marked inward rectification starting around -10 mV. Although neither 300 microM alphabeta-methylene-ATP nor 300 microM betagamma-methylene-ATP induced any currents, 100 microM ATPgammaS and 100 microM 2-methylthio-ATP evoked inward currents of which amplitude was about 60% of the control currents evoked by 100 microM ATP. PPADS, one of P2 receptor antagonists, inhibited the ATP-evoked currents in a time- and a concentration-dependent manners (IC(50)=19 microM at 2 min). Permeant Ca(2+) inhibited the ATP-evoked currents in the range of millimolars (IC(50)=7 mM); however, Cd(2+) (1-300 microM), a broad cation channel blocker, facilitated the currents with slow off-response. Zn(2+) in the range of 1-100 microM facilitated the currents whereas Zn(2+) at the concentrations over 100 microM inhibited the currents. These observations suggest that functional P2X receptors are expressed in the hypothalamic arcuate nucleus. The most likely subunit combinations of the P2X receptors are P2X(2)-homomultimer and P2X(2)/P2X(6)-heteromultimer.

  14. Activity-dependent modulation of gonadotrophin-releasing hormone neurone activity by acute oestradiol.

    PubMed

    Romanò, Nicola; Herbison, Allan E

    2012-10-01

    Oestradiol (E₂) exerts potent feedback actions upon gonadotrophin-releasing hormone (GnRH) neurones and part of this feedback action may occur through the rapid action of E₂. Using a transgenic GnRH-Pericam mouse line that allows real-time intracellular calcium concentrations ([Ca²⁺](i)) to be monitored in adult GnRH neurones in a brain slice preparation, we examined the acute effects of 100 pM-100 nM E₂ on [Ca²⁺](i) transients in spontaneously active GnRH neurones. Approximately 30% of GnRH neurones exhibit spontaneous [Ca²⁺](i) transients at a frequency greater than two transients/15 min in adult female mice. In these cells, treatment with an incremental 1, 10, 100 nM E₂ protocol or 100 pM E₂ alone resulted in the suppression or complete cessation of [Ca²⁺](i) transients in 15 of 18 (83%) GnRH neurones. This effect was mimicked by E₂ bound to albumin, suggesting a membrane site of action, and was maintained in oestrogen receptor β knockout mice, indicating that this receptor is not essential for the rapid suppression of [Ca²⁺](i) transients. These findings contrast with those GnRH neurones exhibiting very few or no [Ca²⁺](i) transients (< 2 transients/15 min) that exhibit the opposite response of being activated by acute E₂. A series of dual calcium-cell-attached electrical recordings showed that [Ca²⁺](i) transients were associated with GnRH neurone burst firing and that E₂ suppression or activation of [Ca²⁺](i) transients was mirrored by a depression or initiation of burst firing. Taken together, these studies demonstrate that the acute actions of E₂ on GnRH neurones are critically dependent upon their pattern of burst firing.

  15. Differences in agonist dissociation constant estimates for 5-HT at 5-HT2-receptors: a problem of acute desensitization?

    PubMed Central

    Leff, P.; Martin, G. R.

    1988-01-01

    1. The agonist dissociation constant for 5-hydroxytryptamine (5-HT) was estimated in the guinea-pig isolated trachea by the method of receptor inactivation. The value obtained (pKA = 6.45) was significantly lower than estimates previously obtained in the rabbit aorta and rat jugular vein, although all three tissues are supposed to contain the same 5-HT2 class of receptor. 2. The antagonist dissociation constant for alpha,alpha-dimethyltryptamine was also estimated in the guinea-pig trachea. The pKB value (5.43) was not significantly different from previous estimates in the rabbit aorta and rat jugular vein, consistent with receptor homogeneity between the three tissues. 3. The effect-time profiles corresponding to individual 5-HT applications were more transient in the guinea-pig trachea than in the rabbit aorta. This difference could be accounted for using a simple model of acute receptor desensitization (Leff, 1986), assuming that the conversion of active agonist-receptor complexes into inactive ones was faster in the guinea-pig trachea than in the rabbit aorta. 4. Computer simulation of the desensitization model showed that the discrepancy of pKA estimates for 5-HT between the rabbit aorta and guinea-pig trachea could also be explained using the same rate constant difference that accounted for the difference in effect-time profiles. This analysis indicated that the estimate made in the trachea was erroneously low, whereas that made in the aorta was concluded to be correct. 5. The apparent association between transience of response and pKA estimates is discussed with particular attention to the reliability of agonist affinity estimates in receptor classification. PMID:3228675

  16. Dissociated functional connectivity profiles for motor and attention deficits in acute right-hemisphere stroke.

    PubMed

    Baldassarre, Antonello; Ramsey, Lenny; Rengachary, Jennifer; Zinn, Kristi; Siegel, Joshua S; Metcalf, Nicholas V; Strube, Michael J; Snyder, Abraham Z; Corbetta, Maurizio; Shulman, Gordon L

    2016-07-01

    Strokes often cause multiple behavioural deficits that are correlated at the population level. Here, we show that motor and attention deficits are selectively associated with abnormal patterns of resting state functional connectivity in the dorsal attention and motor networks. We measured attention and motor deficits in 44 right hemisphere-damaged patients with a first-time stroke at 1-2 weeks post-onset. The motor battery included tests that evaluated deficits in both upper and lower extremities. The attention battery assessed both spatial and non-spatial attention deficits. Summary measures for motor and attention deficits were identified through principal component analyses on the raw behavioural scores. Functional connectivity in structurally normal cortex was estimated based on the temporal correlation of blood oxygenation level-dependent signals measured at rest with functional magnetic resonance imaging. Any correlation between motor and attention deficits and between functional connectivity in the dorsal attention network and motor networks that might spuriously affect the relationship between each deficit and functional connectivity was statistically removed. We report a double dissociation between abnormal functional connectivity patterns and attention and motor deficits, respectively. Attention deficits were significantly more correlated with abnormal interhemispheric functional connectivity within the dorsal attention network than motor networks, while motor deficits were significantly more correlated with abnormal interhemispheric functional connectivity patterns within the motor networks than dorsal attention network. These findings indicate that functional connectivity patterns in structurally normal cortex following a stroke link abnormal physiology in brain networks to the corresponding behavioural deficits.

  17. Acute treatment with 17beta-estradiol attenuates astrocyte-astrocyte and astrocyte-neuron communication.

    PubMed

    Rao, Shilpa P; Sikdar, Sujit Kumar

    2007-12-01

    Astrocytes are now recognized as dynamic signaling elements in the brain. Bidirectional communication between neurons and astrocytes involves integration of neuronal inputs by astrocytes and release of gliotransmitters that modulate neuronal excitability and synaptic transmission. The ovarian steroid hormone, 17beta-estradiol, in addition to its rapid actions on neuronal electrical activity can rapidly alter astrocyte intracellular calcium concentration ([Ca2+]i) through a membrane-associated estrogen receptor. Using calcium imaging and electrophysiological techniques, we investigated the functional consequences of acute treatment with estradiol on astrocyte-astrocyte and astrocyte-neuron communication in mixed hippocampal cultures. Mechanical stimulation of an astrocyte evoked a [Ca2+]i rise in the stimulated astrocyte, which propagated to the surrounding astrocytes as a [Ca2+]i wave. Following acute treatment with estradiol, the amplitude of the [Ca2+]i elevation in astrocytes around the stimulated astrocyte was attenuated. Further, estradiol inhibited the [Ca2+]i rise in individual astrocytes in response to the metabotropic glutamate receptor agonist, trans-(+/-)-1-amino-1,3-cyclopentanedicarboxylic acid. Mechanical stimulation of astrocytes induced [Ca2+]i elevations and electrophysiological responses in adjacent neurons. Estradiol rapidly attenuated the astrocyte-evoked glutamate-mediated [Ca2+]i rise and slow inward current in neurons. Also, the incidence of astrocyte-induced increase in spontaneous postsynaptic current frequency was reduced in the presence of estradiol. The effects of estradiol were stereo-specific and reversible following washout. These findings may indicate that the regulation of neuronal excitability and synaptic transmission by astrocytes is sensitive to rapid estradiol-mediated hormonal control.

  18. Nucleus accumbens neuronal activity correlates to the animal's behavioral response to acute and chronic methylphenidate.

    PubMed

    Claussen, Catherine M; Chong, Samuel L; Dafny, Nachum

    2014-04-22

    Acute and chronic methylphenidate (MPD) exposure was recorded simultaneously for the rat's locomotor activity and the nucleus accumbens (NAc) neuronal activity. The evaluation of the neuronal events was based on the animal's behavior response to chronic MPD administration: 1) Animals exhibiting behavioral sensitization, 2) Animals exhibiting behavioral tolerance. The experiment lasted for 10days with four groups of animals; saline, 0.6, 2.5, and 10.0mg/kg MPD. For the main behavioral findings, about half of the animals exhibited behavioral sensitization or behavioral tolerance to 0.6, 2.5, and/or 10mg/kg MPD respectively. Three hundred and forty one NAc neuronal units were evaluated. Approximately 80% of NAc units responded to 0.6, 2.5, and 10.0mg/kg MPD. When the neuronal activity was analyzed based on the animals' behavioral response to chronic MPD exposure, significant differences were seen between the neuronal population responses recorded from animals that expressed behavioral sensitization when compared to the NAc neuronal responses recorded from animals exhibiting behavioral tolerance. Three types of neurophysiological sensitization and neurophysiological tolerance can be recognized following chronic MPD administration to the neuronal populations. Collectively, these findings show that the same dose of chronic MPD can elicit either behavioral tolerance or behavioral sensitization. Differential statistical analyses were used to verify our hypothesis that the neuronal activity recorded from animals exhibiting behavioral sensitization will respond differently to MPD compared to those animals exhibiting behavioral tolerance, thus, suggesting that it is essential to record the animal's behavior concomitantly with neuronal recordings.

  19. Repetitive acute intermittent hypoxia increases growth/neurotrophic factor expression in non-respiratory motor neurons.

    PubMed

    Satriotomo, I; Nichols, N L; Dale, E A; Emery, A T; Dahlberg, J M; Mitchell, G S

    2016-05-13

    Repetitive acute intermittent hypoxia (rAIH) increases growth/trophic factor expression in respiratory motor neurons, thereby eliciting spinal respiratory motor plasticity and/or neuroprotection. Here we demonstrate that rAIH effects are not unique to respiratory motor neurons, but are also expressed in non-respiratory, spinal alpha motor neurons and upper motor neurons of the motor cortex. In specific, we used immunohistochemistry and immunofluorescence to assess growth/trophic factor protein expression in spinal sections from rats exposed to AIH three times per week for 10weeks (3×wAIH). 3×wAIH increased brain-derived neurotrophic factor (BDNF), its high-affinity receptor, tropomyosin receptor kinase B (TrkB), and phosphorylated TrkB (pTrkB) immunoreactivity in putative alpha motor neurons of spinal cervical 7 (C7) and lumbar 3 (L3) segments, as well as in upper motor neurons of the primary motor cortex (M1). 3×wAIH also increased immunoreactivity of vascular endothelial growth factor A (VEGFA), the high-affinity VEGFA receptor (VEGFR-2) and an important VEGF gene regulator, hypoxia-inducible factor-1α (HIF-1α). Thus, rAIH effects on growth/trophic factors are characteristic of non-respiratory as well as respiratory motor neurons. rAIH may be a useful tool in the treatment of disorders causing paralysis, such as spinal injury and motor neuron disease, as a pretreatment to enhance motor neuron survival during disease, or as preconditioning for cell-transplant therapies.

  20. Caudate neuronal recording in freely behaving animals following acute and chronic dose response methylphenidate exposure.

    PubMed

    Claussen, Catherine M; Dafny, Nachum

    2015-09-01

    The misuse and abuse of the psychostimulant, methylphenidate (MPD) the drug of choice in the treatment of attention deficit hyperactivity disorder (ADHD) has seen a sharp uprising in recent years among both youth and adults for its cognitive enhancing effects and for recreational purposes. This uprise in illicit use has lead to many questions concerning the long-term consequences of MPD exposure. The objective of this study was to record animal behavior concomitantly with the caudate nucleus (CN) neuronal activity following acute and repetitive (chronic) dose response exposure to methylphenidate (MPD). A saline control and three MPD dose (0.6, 2.5, and 10.0mg/kg) groups were used. Behaviorally, the same MPD dose in some animals following chronic MPD exposure elicited behavioral sensitization and other animals elicited behavioral tolerance. Based on this finding, the CN neuronal population recorded from animals expressing behavioral sensitization was also evaluated separately from CN neurons recorded from animals expressing behavioral tolerance to chronic MPD exposure, respectively. Significant differences in CN neuronal population responses between the behaviorally sensitized and the behaviorally tolerant animals were observed for the 2.5 and 10.0mg/kg MPD exposed groups. For 2.5mg/kg MPD, behaviorally sensitized animals responded by decreasing their firing rates while behaviorally tolerant animals showed mainly an increase in their firing rates. The CN neuronal responses recorded from the behaviorally sensitized animals following 10.0mg/kg MPD responded by increasing their firing rates whereas the CN neuronal recordings from the behaviorally tolerant animals showed that approximately half decreased their firing rates in response to 10.0mg/kg MPD exposure. The comparison of percentage change in neuronal firing rates showed that the behaviorally tolerant animals trended to exhibit increases in their neuronal firing rates at ED1 following initial MPD exposure and

  1. Calcium Imaging of AM Dyes Following Prolonged Incubation in Acute Neuronal Tissue

    PubMed Central

    Morley, John W.; Tapson, Jonathan; Breen, Paul P.; van Schaik, André

    2016-01-01

    Calcium-imaging is a sensitive method for monitoring calcium dynamics during neuronal activity. As intracellular calcium concentration is correlated to physiological and pathophysiological activity of neurons, calcium imaging with fluorescent indicators is one of the most commonly used techniques in neuroscience today. Current methodologies for loading calcium dyes into the tissue require prolonged incubation time (45–150 min), in addition to dissection and recovery time after the slicing procedure. This prolonged incubation curtails experimental time, as tissue is typically maintained for 6–8 hours after slicing. Using a recently introduced recovery chamber that extends the viability of acute brain slices to more than 24 hours, we tested the effectiveness of calcium AM staining following long incubation periods post cell loading and its impact on the functional properties of calcium signals in acute brain slices and wholemount retinae. We show that calcium dyes remain within cells and are fully functional >24 hours after loading. Moreover, the calcium dynamics recorded >24 hrs were similar to the calcium signals recorded in fresh tissue that was incubated for <4 hrs. These results indicate that long exposure of calcium AM dyes to the intracellular cytoplasm did not alter the intracellular calcium concentration, the functional range of the dye or viability of the neurons. This data extends our previous work showing that a custom recovery chamber can extend the viability of neuronal tissue, and reliable data for both electrophysiology and imaging can be obtained >24hrs after dissection. These methods will not only extend experimental time for those using acute neuronal tissue, but also may reduce the number of animals required to complete experimental goals. PMID:27183102

  2. Adaptations in responsiveness of brainstem pain-modulating neurons in acute compared with chronic inflammation.

    PubMed

    Cleary, Daniel R; Heinricher, Mary M

    2013-06-01

    Despite similar behavioral hypersensitivity, acute and chronic pain have distinct neural bases. We used intraplantar injection of complete Freund's adjuvant to directly compare activity of pain-modulating neurons in the rostral ventromedial medulla (RVM) in acute vs chronic inflammation. Heat-evoked and von Frey-evoked withdrawal reflexes and corresponding RVM neuronal activity were recorded in lightly anesthetized animals either during the first hour after complete Freund's adjuvant injection (acute) or 3 to 10 days later (chronic). Thermal and modest mechanical hyperalgesia during acute inflammation were associated with increases in the spontaneous activity of pain-facilitating ON-cells and suppression of pain-inhibiting OFF-cells. Acute hyperalgesia was reversed by RVM block, showing that the increased activity of RVM ON-cells is necessary for acute behavioral hypersensitivity. In chronic inflammation, thermal hyperalgesia had resolved but mechanical hyperalgesia had become pronounced. The spontaneous discharges of ON- and OFF-cells were not different from those in control subjects, but the mechanical response thresholds for both cell classes were reduced into the innocuous range. RVM block in the chronic condition worsened mechanical hyperalgesia. These studies identify distinct contributions of RVM ON- and OFF-cells to acute and chronic inflammatory hyperalgesia. During early immune-mediated inflammation, ON-cell spontaneous activity promotes hyperalgesia. After inflammation is established, the antinociceptive influence of OFF-cells is dominant, yet the lowered threshold for the OFF-cell pause allows behavioral responses to stimuli that would normally be considered innocuous. The efficacy of OFF-cells in counteracting sensitization of ascending transmission pathways could therefore be an important determining factor in development of chronic inflammatory pain.

  3. Combined Exposure to Simulated Microgravity and Acute or Chronic Radiation Reduces Neuronal Network Integrity and Survival

    PubMed Central

    Quintens, Roel; Samari, Nada; de Saint-Georges, Louis; van Oostveldt, Patrick; Baatout, Sarah; Benotmane, Mohammed Abderrafi

    2016-01-01

    During orbital or interplanetary space flights, astronauts are exposed to cosmic radiations and microgravity. However, most earth-based studies on the potential health risks of space conditions have investigated the effects of these two conditions separately. This study aimed at assessing the combined effect of radiation exposure and microgravity on neuronal morphology and survival in vitro. In particular, we investigated the effects of simulated microgravity after acute (X-rays) or during chronic (Californium-252) exposure to ionizing radiation using mouse mature neuron cultures. Acute exposure to low (0.1 Gy) doses of X-rays caused a delay in neurite outgrowth and a reduction in soma size, while only the high dose impaired neuronal survival. Of interest, the strongest effect on neuronal morphology and survival was evident in cells exposed to microgravity and in particular in cells exposed to both microgravity and radiation. Removal of neurons from simulated microgravity for a period of 24 h was not sufficient to recover neurite length, whereas the soma size showed a clear re-adaptation to normal ground conditions. Genome-wide gene expression analysis confirmed a modulation of genes involved in neurite extension, cell survival and synaptic communication, suggesting that these changes might be responsible for the observed morphological effects. In general, the observed synergistic changes in neuronal network integrity and cell survival induced by simulated space conditions might help to better evaluate the astronaut's health risks and underline the importance of investigating the central nervous system and long-term cognition during and after a space flight. PMID:27203085

  4. Myelin-associated glycoprotein (MAG) protects neurons from acute toxicity using a ganglioside-dependent mechanism.

    PubMed

    Mehta, Niraj R; Nguyen, Thien; Bullen, John W; Griffin, John W; Schnaar, Ronald L

    2010-03-17

    Myelin-associated glycoprotein (MAG), a protein expressed on the innermost wrap of myelin, contributes to long-term axon stability as evidenced by progressive axon degeneration in Mag-null mice. Recently, MAG was also found to protect axons from acute toxic insults. In the current study, rat dorsal root ganglion neurons were cultured on control substrata and substrata adsorbed with myelin proteins. Neurons on myelin-adsorbed surfaces were resistant to acute degeneration of neurites induced by vincristine, a cancer chemotherapeutic agent with neuropathic side effects. Myelin-mediated protection was reversed by anti-MAG antibody and was absent when cells were cultured on extracts from Mag-null mouse myelin, confirming the protective role of MAG. Gangliosides (sialylated glycosphingolipids) are one functional class of axonal receptors for MAG. In the current studies, a direct role for gangliosides in mediating the acute protective effects of MAG was established. Treatment of neurons with sialidase, an enzyme that cleaves the terminal sialic acids required for MAG binding, reversed MAG's protective effect, as did treatment with (1R,2R)-1-phenyl-2-hexadecanoylamino-3-pyrrolidino-1-propanol, an inhibitor of glycosphingolipid biosynthesis. In contrast, treatment with phosphatidylinositol-specific phospholipase C, an enzyme that cleaves Nogo receptors (NgR, another class of MAG receptor), or with a peptide inhibitor of an NgR-associated signaling molecule p75(NTR), failed to diminish MAG-mediated protection. Inhibiting the Rho-associated protein kinase ROCK reversed protection. We conclude that MAG protects neurites from acute toxic insult via a ganglioside-mediated signaling pathway that involves activation of RhoA. Understanding MAG-mediated protection may provide opportunities to reduce axonal damage and loss.

  5. Nicotinamide reduces acute cortical neuronal death and edema in the traumatically injured brain.

    PubMed

    Hoane, Michael R; Gilbert, David R; Holland, Michael A; Pierce, Jeremy L

    2006-11-06

    Previous studies have shown that administration of nicotinamide (Vitamin B(3)) in animal models of traumatic brain injury (TBI) and ischemia significantly reduced the size of infarction or injury and improved functional recovery. The present study evaluated the ability of nicotinamide to provide acute neuroprotection and edema reduction following TBI. Groups of rats were assigned to nicotinamide (500mg/kg) or saline (1.0ml/kg) treatment conditions and received contusion injuries or sham surgeries. Drug treatment was administered 15min following injury. Brains were harvested 24h later and either processed for histology or water content. Frozen sections were stained with the degenerating neuron stain (Fluoro-Jade B) (FJ) and cell counts were performed at the site of injury. Additional brains were processed for water content (a measure of injury-induced edema). Results of this study showed that administration of nicotinamide following TBI significantly reduced the number of FJ(+) neurons in the injured cortex compared to saline-treated animals. Examination of the water content of the brains also revealed that administration of nicotinamide significantly attenuated the amount of water compared to saline-treated animals in the injured cortex. These results indicate that nicotinamide administration significantly reduced neuronal death and attenuated cerebral edema following injury. The current findings suggest that nicotinamide significantly modulates acute pathophysiological processes following injury and that this may account for its beneficial effects on recovery of function following injury.

  6. Endoplasmic reticulum stress-regulated CXCR3 pathway mediates inflammation and neuronal injury in acute glaucoma.

    PubMed

    Ha, Y; Liu, H; Xu, Z; Yokota, H; Narayanan, S P; Lemtalsi, T; Smith, S B; Caldwell, R W; Caldwell, R B; Zhang, W

    2015-10-08

    Acute glaucoma is a leading cause of irreversible blindness in East Asia. The mechanisms underlying retinal neuronal injury induced by a sudden rise in intraocular pressure (IOP) remain obscure. Here we demonstrate that the activation of CXCL10/CXCR3 axis, which mediates the recruitment and activation of inflammatory cells, has a critical role in a mouse model of acute glaucoma. The mRNA and protein expression levels of CXCL10 and CXCR3 were significantly increased after IOP-induced retinal ischemia. Blockade of the CXCR3 pathway by deleting CXCR3 gene significantly attenuated ischemic injury-induced upregulation of inflammatory molecules (interleukin-1β and E-selectin), inhibited the recruitment of microglia/monocyte to the superficial retina, reduced peroxynitrite formation, and prevented the loss of neurons within the ganglion cell layer. In contrast, intravitreal delivery of CXCL10 increased leukocyte recruitment and retinal cell apoptosis. Inhibition of endoplasmic reticulum (ER) stress with chemical chaperones partially blocked ischemic injury-induced CXCL10 upregulation, whereas induction of ER stress with tunicamycin enhanced CXCL10 expression in retina and primary retinal ganglion cells. Interestingly, deleting CXCR3 attenuated ER stress-induced retinal cell death. In conclusion, these results indicate that ER stress-medicated activation of CXCL10/CXCR3 pathway has an important role in retinal inflammation and neuronal injury after high IOP-induced ischemia.

  7. Dissociation between neuronal activity in sensorimotor cortex and hand movement revealed as a function of movement rate.

    PubMed

    Hermes, Dora; Siero, Jeroen C W; Aarnoutse, Erik J; Leijten, Frans S S; Petridou, Natalia; Ramsey, Nick F

    2012-07-11

    It is often assumed that similar behavior is generated by the same brain activity. However, this does not take into account the brain state or recent behavioral history and movement initiation or continuation may not be similarly generated in the brain. To study whether similar movements are generated by the same brain activity, we measured neuronal population activity during repeated movements. Three human subjects performed a motor repetition task in which they moved their hand at four different rates (0.3, 0.5, 1, and 2 Hz). From high-resolution electrocorticography arrays implanted on motor and sensory cortex, high-frequency power (65-95 Hz) was extracted as a measure of neuronal population activity. During the two faster movement rates, high-frequency power was significantly suppressed, whereas movement parameters remained highly similar. This suppression was nonlinear: after the initial movement, neuronal population activity was reduced most strongly, and the data fit a model in which a fast decline rapidly converged to saturation. The amplitude of the beta-band suppression did not change with different rates. However, at the faster rates, beta power did not return to baseline between movements but remained suppressed. We take these findings to indicate that the extended beta suppression at the faster rates, which may suggest a release of inhibition in motor cortex, facilitates movement initiation. These results show that the relationship between behavior and neuronal activity is not consistent: recent movement influences the state of motor cortex and facilitates next movements by reducing the required level of neuronal activity.

  8. Peroxisome proliferator-activated receptor α mediates acute effects of palmitoylethanolamide on sensory neurons.

    PubMed

    Khasabova, Iryna A; Xiong, Yee; Coicou, Lia G; Piomelli, Daniele; Seybold, Virginia

    2012-09-12

    The amplitude of the depolarization-evoked Ca2+ transient is larger in dorsal root ganglion (DRG) neurons from tumor-bearing mice compared with that of neurons from naive mice, and the change is mimicked by coculturing DRG neurons with the fibrosarcoma cells used to generate the tumors (Khasabova et al., 2007). The effect of palmitoylethanolamide (PEA), a ligand for the peroxisome proliferator-activated receptor α (PPARα), was determined on the evoked-Ca2+ transient in the coculture condition. The level of PEA was reduced in DRG cells from tumor-bearing mice as well as those cocultured with fibrosarcoma cells. Pretreatment with PEA, a synthetic PPARα agonist (GW7647), or ARN077, an inhibitor of the enzyme that hydrolyzes PEA, acutely decreased the amplitude of the evoked Ca2+ transient in small DRG neurons cocultured with fibrosarcoma cells. The PPARα antagonist GW6471 blocked the effect of each. In contrast, the PPARα agonist was without effect in the control condition, but the antagonist increased the amplitude of the Ca2+ transient, suggesting that PPARα receptors are saturated by endogenous ligand under basal conditions. Effects of drugs on mechanical sensitivity in vivo paralleled their effects on DRG neurons in vitro. Local injection of ARN077 decreased mechanical hyperalgesia in tumor-bearing mice, and the effect was blocked by GW6471. These data support the conclusion that the activity of DRG neurons is rapidly modulated by PEA through a PPARα-dependent mechanism. Moreover, agents that increase the activity of PPARα may provide a therapeutic strategy to reduce tumor-evoked pain.

  9. Cellular and molecular characterization of Ca2+ currents in acutely isolated, adult rat neostriatal neurons.

    PubMed

    Bargas, J; Howe, A; Eberwine, J; Cao, Y; Surmeier, D J

    1994-11-01

    Ca2+ currents in acutely isolated, adult rat neostriatal neurons were studied with whole-cell voltage-clamp techniques. In the vast majority of neurons (approximately 90%, n > 250), currents were exclusively of the high-voltage-activated (HVA) type. HVA currents activated near -40 mV and reached their maximum amplitude near 0 mV. Quasi-steady-state inactivation curves in many neurons were well fitted only with a sum of Boltzmann functions, suggesting that the HVA currents were heterogeneous. Although the block of whole-cell current by Cd2+ was well fitted with a single isotherm having an IC50 of near 1 microM, experiments with organic channel antagonists suggested that at least four types of HVA channels were expressed by most cells. On average, the L-channel antagonist nifedipine (5-10 microM) blocked 31 +/- 10% of the whole-cell current (n = 20), the N-channel antagonist omega-conotoxin GVIA (omega-CgTx) (2-5 microM) blocked 27 +/- 11% (n = 20), and the P-channel antagonist omega-agatoxin IVA (100-500 nM) blocked 21 +/- 10% (n = 18). In many neurons, the block by omega-CgTx was partially or completely reversible. In cells tested with a combination of these antagonists, 34 +/- 17% of the peak Ca2+ current remained unblocked (n = 13). Single-cell expression profiling of medium-sized neurons revealed the presence of rbA and rbB Ca2+ channel alpha 1 subunit mRNAs but low or undetectable levels of rbC mRNA (n = 12). These findings suggest that although adult neostriatal projection neurons do not express significant levels of LVA Ca2+ current, they do express a pharmacologically and structurally heterogeneous population of HVA currents.

  10. Intermittent fasting dissociates beneficial effects of dietary restriction on glucose metabolism and neuronal resistance to injury from calorie intake.

    PubMed

    Anson, R Michael; Guo, Zhihong; de Cabo, Rafael; Iyun, Titilola; Rios, Michelle; Hagepanos, Adrienne; Ingram, Donald K; Lane, Mark A; Mattson, Mark P

    2003-05-13

    Dietary restriction has been shown to have several health benefits including increased insulin sensitivity, stress resistance, reduced morbidity, and increased life span. The mechanism remains unknown, but the need for a long-term reduction in caloric intake to achieve these benefits has been assumed. We report that when C57BL6 mice are maintained on an intermittent fasting (alternate-day fasting) dietary-restriction regimen their overall food intake is not decreased and their body weight is maintained. Nevertheless, intermittent fasting resulted in beneficial effects that met or exceeded those of caloric restriction including reduced serum glucose and insulin levels and increased resistance of neurons in the brain to excitotoxic stress. Intermittent fasting therefore has beneficial effects on glucose regulation and neuronal resistance to injury in these mice that are independent of caloric intake.

  11. A neuronal population in hypothalamus that dramatically resists acute ischemic injury compared to neocortex.

    PubMed

    Brisson, C Devin; Andrew, R David

    2012-07-01

    Pyramidal neurons (PyNs) of the cortex are highly susceptible to acute stroke damage, yet "lower" brain regions like hypothalamus and brain stem better survive global ischemia. Here we show for the first time that a "lower" neuron population intrinsically resists acute strokelike injury. In rat brain slices deprived of oxygen and glucose (OGD), we imaged anoxic depolarization (AD) as it propagated through neocortex or hypothalamus. AD, the initial electrophysiological event of stroke, is a front of depolarization that drains residual energy in compromised gray matter. The extent of AD reliably determines ensuing cortical damage, but do all CNS neurons generate a robust AD? During 10 min of OGD, PyNs depolarize without functional recovery. In contrast, magnocellular neuroendocrine cells (MNCs) in hypothalamus under identical stress generate a weak and delayed AD, resist complete depolarization, and rapidly repolarize when oxygen and glucose are restored. They recover their membrane potential, input resistance, and spike amplitude and can survive multiple OGD exposures. Two-photon microscopy in slices derived from a fluorescent mouse line confirms this protection, revealing PyN swelling and dendritic beading after OGD, whereas MNCs are not injured. Exposure to the Na(+)-K(+)-ATPase inhibitor ouabain (100 μM) induces AD similar to OGD in both cell types. Moreover, elevated extracellular K(+) concentration ([K(+)](o)) evokes spreading depression (SD), a milder version of AD, in PyNs but not MNCs. Therefore overriding the pump by OGD, ouabain, or elevated [K(+)](o) evokes a propagating depolarization in higher gray matter but not in MNCs. We suggest that variation in Na(+)-K(+)-ATPase pump efficiency during ischemia injury determines whether a neuronal type succumbs to or resists stroke.

  12. Pronase acutely modifies high voltage-activated calcium currents and cell properties of Lymnaea neurons.

    PubMed

    Hermann, P M; Lukowiak, K; Wildering, W C; Bulloch, A G

    1997-12-01

    Pronase E ('pronase') is one of the proteolytic enzymes that are used in preparative procedures such as cell isolation and to soften the sheath of invertebrate ganglia. Although several effects of proteolytic enzymes on the physiology of non-neuronal tissues have been described, the effects of these enzymes on central neurons have received little attention. We examined the effects of bath-applied pronase on neurons in the Lymnaea central nervous system and in vitro. Pronase caused action potential broadening in neurons that exhibit a shoulder on the repolarization phase of their action potentials. This effect of pronase was accompanied by, although unrelated to, a depolarization and decrease in action potential interval. Some, but not all, effects of pronase in the central nervous system were reversible. For example, the decreases in membrane potential and action potential interval were both reversed after approximately 1 h of washing with saline. However, the effect of pronase on the action potential duration was not reversed after a period of 90 min. The modulation of action potential width prompted us to examine Ca2+ currents. Exposure to pronase resulted in an increase in both peak and late high voltage-activated Ca2+ currents in isolated neurons. Pronase neither changed the inactivation rate nor caused a shift in the current-voltage relationship of the current. The changes in action potential duration could be prevented by application of 0.1 mM Cd2+, indicating that the action potential broadening caused by pronase depends on Ca2+ influx. This is the first systematic study of the acute and direct actions of pronase on Ca2+ currents and cell properties both in the CNS and in vitro.

  13. Quasimodo mediates daily and acute light effects on Drosophila clock neuron excitability.

    PubMed

    Buhl, Edgar; Bradlaugh, Adam; Ogueta, Maite; Chen, Ko-Fan; Stanewsky, Ralf; Hodge, James J L

    2016-11-22

    We have characterized a light-input pathway regulating Drosophila clock neuron excitability. The molecular clock drives rhythmic electrical excitability of clock neurons, and we show that the recently discovered light-input factor Quasimodo (Qsm) regulates this variation, presumably via an Na(+), K(+), Cl(-) cotransporter (NKCC) and the Shaw K(+) channel (dKV3.1). Because of light-dependent degradation of the clock protein Timeless (Tim), constant illumination (LL) leads to a breakdown of molecular and behavioral rhythms. Both overexpression ((OX)) and knockdown ((RNAi)) of qsm, NKCC, or Shaw led to robust LL rhythmicity. Whole-cell recordings of the large ventral lateral neurons (l-LNv) showed that altering Qsm levels reduced the daily variation in neuronal activity: qsm(OX) led to a constitutive less active, night-like state, and qsm(RNAi) led to a more active, day-like state. Qsm also affected daily changes in K(+) currents and the GABA reversal potential, suggesting a role in modifying membrane currents and GABA responses in a daily fashion, potentially modulating light arousal and input to the clock. When directly challenged with blue light, wild-type l-LNvs responded with increased firing at night and no net response during the day, whereas altering Qsm, NKKC, or Shaw levels abolished these day/night differences. Finally, coexpression of Shaw(OX) and NKCC(RNAi) in a qsm mutant background restored LL-induced behavioral arrhythmicity and wild-type neuronal activity patterns, suggesting that the three genes operate in the same pathway. We propose that Qsm affects both daily and acute light effects in l-LNvs probably acting on Shaw and NKCC.

  14. Modifications of excitatory and inhibitory transmission in rat hippocampal pyramidal neurons by acute lithium treatment.

    PubMed

    Wakita, Masahito; Nagami, Hideaki; Takase, Yuko; Nakanishi, Ryoji; Kotani, Naoki; Akaike, Norio

    2015-08-01

    The acute effects of high-dose Li(+) treatment on glutamatergic and GABAergic transmissions were studied in the "synaptic bouton" preparation of isolated rat hippocampal pyramidal neurons by using focal electrical stimulation. Both action potential-dependent glutamatergic excitatory and GABAergic inhibitory postsynaptic currents (eEPSC and eIPSC, respectively) were dose-dependently inhibited in the external media containing 30-150 mM Li(+), but the sensitivity for Li(+) was greater tendency for eEPSCs than for eIPSCs. When the effects of Li(+) on glutamate or GABAA receptor-mediated whole-cell responses (IGlu and IGABA) elicited by an exogenous application of glutamate or GABA were examined in the postsynaptic soma membrane of CA3 neurons, Li(+) slightly inhibited both IGlu and IGABA at the 150 mM Li(+) concentration. Present results suggest that acute treatment with high concentrations of Li(+) acts preferentially on presynaptic terminals, and that the Li(+)-induced inhibition may be greater for excitatory than for inhibitory transmission.

  15. The role of parkin in the differential susceptibility of tuberoinfundibular and nigrostriatal dopamine neurons to acute toxicant exposure.

    PubMed

    Benskey, Matthew J; Manfredsson, Fredric P; Lookingland, Keith J; Goudreau, John L

    2015-01-01

    Parkinson disease causes degeneration of nigrostriatal dopamine (DA) neurons, while tuberoinfundibular DA neurons remain unaffected. A similar pattern is observed following exposure to 1-methy-4-phenyl-1,2,3,6-tetrahydropyradine (MPTP). The mechanism of tuberoinfundibular neuronal recovery from MPTP is associated with up-regulation of parkin protein. Here we tested if parkin mediates tuberoinfundibular neuronal recovery from MPTP by knocking-down parkin in tuberoinfundibular neurons using recombinant adeno-associated virus (rAAV), expressing a short hairpin RNA (shRNA) directed toward parkin. Following knockdown, axon terminal DA and tyrosine hydroxylase (TH) concentrations were analyzed 24h post-MPTP administration. rAAV-shRNA-mediated knockdown of endogenous parkin rendered tuberoinfundibular neurons susceptible to MPTP induced terminal DA loss, but not TH loss, within 24h post-MPTP. To determine if the neuroprotective benefits of parkin up-regulation could be translated to nigrostriatal neurons, rAAV expressing human parkin was injected into the substantia nigra of mice and axon terminal DA and TH concentrations were analyzed 24h post-MPTP. Nigral parkin over-expression prevented loss of TH in the axon terminals and soma of nigrostriatal neurons, but had no effect on terminal DA loss within 24h post-MPTP. These data show that parkin is necessary for the recovery of terminal DA concentrations within tuberoinfundibular neurons following acute MPTP administration, and parkin can rescue MPTP-induced decreases in TH within nigrostriatal neurons.

  16. Visually guided whole cell patch clamp of mouse supraoptic nucleus neurons in cultured and acute conditions.

    PubMed

    Stachniak, Tevye J E; Bourque, Charles W

    2006-07-01

    Recent advances in neuronal culturing techniques have supplied a new set of tools for studying neural tissue, providing effective means to study molecular aspects of regulatory elements in the supraoptic nucleus of the hypothalamus (SON). To combine molecular biology techniques with electrophysiological recording, we modified an organotypic culture protocol to permit transfection and whole cell patch-clamp recordings from SON cells. Neonatal mouse brain coronal sections containing the SON were dissected out, placed on a filter insert in culture medium, and incubated for at least 4 days to allow attachment to the insert. The SON was identifiable using gross anatomical landmarks, which remained intact throughout the culturing period. Immunohistochemical staining identified both vasopressinergic and oxytocinergic cells present in the cultures, typically appearing in well-defined clusters. Whole cell recordings from these cultures demonstrated that certain properties of the neonatal mouse SON were comparable to adult mouse magnocellular neurons. SON neurons in both neonatal cultures and acute adult slices showed similar sustained outward rectification above -60 mV and action potential broadening during evoked activity. Membrane potential, input resistance, and rapidly inactivating potassium current density (IA) were reduced in the cultures, whereas whole cell capacitance and spontaneous synaptic excitation were increased, perhaps reflecting developmental changes in cell physiology that warrant further study. The use of the outlined organotypic culturing procedures will allow the study of such electrophysiological properties of mouse SON using whole cell patch-clamp, in addition to various molecular, techniques that require longer incubation times.

  17. Fractal Dimension of EEG Activity Senses Neuronal Impairment in Acute Stroke

    PubMed Central

    Zappasodi, Filippo; Olejarczyk, Elzbieta; Marzetti, Laura; Assenza, Giovanni; Pizzella, Vittorio; Tecchio, Franca

    2014-01-01

    The brain is a self-organizing system which displays self-similarities at different spatial and temporal scales. Thus, the complexity of its dynamics, associated to efficient processing and functional advantages, is expected to be captured by a measure of its scale-free (fractal) properties. Under the hypothesis that the fractal dimension (FD) of the electroencephalographic signal (EEG) is optimally sensitive to the neuronal dysfunction secondary to a brain lesion, we tested the FD’s ability in assessing two key processes in acute stroke: the clinical impairment and the recovery prognosis. Resting EEG was collected in 36 patients 4–10 days after a unilateral ischemic stroke in the middle cerebral artery territory and 19 healthy controls. National Health Institute Stroke Scale (NIHss) was collected at T0 and 6 months later. Highuchi FD, its inter-hemispheric asymmetry (FDasy) and spectral band powers were calculated for EEG signals. FD was smaller in patients than in controls (1.447±0.092 vs 1.525±0.105) and its reduction was paired to a worse acute clinical status. FD decrease was associated to alpha increase and beta decrease of oscillatory activity power. Larger FDasy in acute phase was paired to a worse clinical recovery at six months. FD in our patients captured the loss of complexity reflecting the global system dysfunction resulting from the structural damage. This decrease seems to reveal the intimate nature of structure-function unity, where the regional neural multi-scale self-similar activity is impaired by the anatomical lesion. This picture is coherent with neuronal activity complexity decrease paired to a reduced repertoire of functional abilities. FDasy result highlights the functional relevance of the balance between homologous brain structures’ activities in stroke recovery. PMID:24967904

  18. Fractal dimension of EEG activity senses neuronal impairment in acute stroke.

    PubMed

    Zappasodi, Filippo; Olejarczyk, Elzbieta; Marzetti, Laura; Assenza, Giovanni; Pizzella, Vittorio; Tecchio, Franca

    2014-01-01

    The brain is a self-organizing system which displays self-similarities at different spatial and temporal scales. Thus, the complexity of its dynamics, associated to efficient processing and functional advantages, is expected to be captured by a measure of its scale-free (fractal) properties. Under the hypothesis that the fractal dimension (FD) of the electroencephalographic signal (EEG) is optimally sensitive to the neuronal dysfunction secondary to a brain lesion, we tested the FD's ability in assessing two key processes in acute stroke: the clinical impairment and the recovery prognosis. Resting EEG was collected in 36 patients 4-10 days after a unilateral ischemic stroke in the middle cerebral artery territory and 19 healthy controls. National Health Institute Stroke Scale (NIHss) was collected at T0 and 6 months later. Highuchi FD, its inter-hemispheric asymmetry (FDasy) and spectral band powers were calculated for EEG signals. FD was smaller in patients than in controls (1.447±0.092 vs 1.525±0.105) and its reduction was paired to a worse acute clinical status. FD decrease was associated to alpha increase and beta decrease of oscillatory activity power. Larger FDasy in acute phase was paired to a worse clinical recovery at six months. FD in our patients captured the loss of complexity reflecting the global system dysfunction resulting from the structural damage. This decrease seems to reveal the intimate nature of structure-function unity, where the regional neural multi-scale self-similar activity is impaired by the anatomical lesion. This picture is coherent with neuronal activity complexity decrease paired to a reduced repertoire of functional abilities. FDasy result highlights the functional relevance of the balance between homologous brain structures' activities in stroke recovery.

  19. Dissociative Disorders

    MedlinePlus

    ... of continuity between thoughts, memories, surroundings, actions and identity. People with dissociative disorders escape reality in ways ... at bay. Symptoms — ranging from amnesia to alternate identities — depend in part on the type of dissociative ...

  20. Acute oral administration of low doses of methylphenidate targets calretinin neurons in the rat septal area

    PubMed Central

    García-Avilés, Álvaro; Albert-Gascó, Héctor; Arnal-Vicente, Isabel; Elhajj, Ebtisam; Sanjuan-Arias, Julio; Sanchez-Perez, Ana María; Olucha-Bordonau, Francisco

    2015-01-01

    Methylphenidate (MPD) is a commonly administered drug to treat children suffering from attention deficit hyperactivity disorder (ADHD). Alterations in septal driven hippocampal theta rhythm may underlie attention deficits observed in these patients. Amongst others, the septo-hippocampal connections have long been acknowledged to be important in preserving hippocampal function. Thus, we wanted to ascertain if MPD administration, which improves attention in patients, could affect septal areas connecting with hippocampus. We used low and orally administered MPD doses (1.3, 2.7 and 5 mg/Kg) to rats what mimics the dosage range in humans. In our model, we observed no effect when using 1.3 mg/Kg MPD; whereas 2.7 and 5 mg/Kg induced a significant increase in c-fos expression specifically in the medial septum (MS), an area intimately connected to the hippocampus. We analyzed dopaminergic areas such as nucleus accumbens and striatum, and found that only 5 mg/Kg induced c-fos levels increase. In these areas tyrosine hydroxylase correlated well with c-fos staining, whereas in the MS the sparse tyrosine hydroxylase fibers did not overlap with c-fos positive neurons. Double immunofluorescence of c-fos with neuronal markers in the septal area revealed that co-localization with choline acethyl transferase, parvalbumin, and calbindin with c-fos did not change with MPD treatment; whereas, calretinin and c-fos double labeled neurons increased after MPD administration. Altogether, these results suggest that low and acute doses of methylphenidate primary target specific populations of caltretinin medial septal neurons. PMID:25852493

  1. Effect of Octreotide on Enteric Motor Neurons in Experimental Acute Necrotizing Pancreatitis

    PubMed Central

    Zou, Duowu; Wu, Wenbin; Li, Zhaoshen

    2012-01-01

    Background/Aims Amelioration of intestinal dysmotility and stasis during the early period of acute necrotizing pancreatitis (ANP) appears to be important to reduce the risks of secondary pancreatic infection. We aimed to characterize the association between the neuropathy of the enteric nervous system and gut dysfunction and to examine the effect of octreotide on motor innervation in the early stage of ANP. Methodology/Principal Findings The rats were randomly divided into eight groups: control+saline; control+octreotide; ANP+saline and ANP+octreotide (24 h, 48 h, 72 h). The spontaneous activity of ileal segments and the response to ACh, l-NNA were recorded. The alterations of myenteric neuronal nitric oxide synthase (nNOS), choline acetyltransferase (CHAT), PGP9.5 and somatostatin receptor 2 (SSTR2) immunoreactive cells were evaluated by immunofluorescence and the protein expression of nNOS and CHAT were evaluated by western blot. We found the amplitude of spontaneous contractions at 48 h and the response to ACh at 24 h declined in the ANP+saline rats. A higher contractile response to both ACh and to l-NNA was observed in the ANP+octreotide group, compared with the ANP+saline rats at 24 h. A significant reduction in the nNOS and cholinergic neurons was observed in ANP+saline rats at the three time points. However, this reduction was greatly ameliorated in the presence of octreotide at 24 h and 48 h. The protein expression of CHAT neurons at 24 h and the nNOS neurons at 48 h in the ANP+octreotide rats was much higher than the ANP+saline rats. Conclusion The pathogenesis of ileus in the early stage of ANP may be related to the neuropathy of the enteric nervous system. Octreotide may reduce the severity of ileus by lessening the damage to enteric motor innervation. PMID:23300603

  2. GnRH neuron firing and response to GABA in vitro depend on acute brain slice thickness and orientation.

    PubMed

    Constantin, Stephanie; Piet, Richard; Iremonger, Karl; Hwa Yeo, Shel; Clarkson, Jenny; Porteous, Robert; Herbison, Allan E

    2012-08-01

    The GnRH neurons exhibit long dendrites and project to the median eminence. The aim of the present study was to generate an acute brain slice preparation that enabled recordings to be undertaken from GnRH neurons maintaining the full extent of their dendrites or axons. A thick, horizontal brain slice was developed, in which it was possible to record from the horizontally oriented GnRH neurons located in the anterior hypothalamic area (AHA). In vivo studies showed that the majority of AHA GnRH neurons projected outside the blood-brain barrier and expressed c-Fos at the time of the GnRH surge. On-cell recordings compared AHA GnRH neurons in the horizontal slice (AHAh) with AHA and preoptic area (POA) GnRH neurons in coronal slices [POA coronal (POAc) and AHA coronal (AHAc), respectively]. AHAh GnRH neurons exhibited tighter burst firing compared with other slice orientations. Although α-Amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) excited GnRH neurons in all preparations, γ-aminobutyric acid (GABA) was excitatory in AHAc and POAc but inhibitory in AHAh slices. GABA(A) receptor postsynaptic currents were the same in AHAh and AHAc slices. Intriguingly, direct activation of GABA(A) or GABA(B) receptors respectively stimulated and inhibited GnRH neurons regardless of slice orientation. Subsequent experiments indicated that net GABA effects were determined by differences in the ratio of GABA(A) and GABA(B) receptor-mediated effects in "long" and "short" dendrites of GnRH neurons in the different slice orientations. These studies document a new brain slice preparation for recording from GnRH neurons with their extensive dendrites/axons and highlight the importance of GnRH neuron orientation relative to the angle of brain slicing in studying these neurons in vitro.

  3. Combined exposure to simulated microgravity and acute or chronic radiation reduces neuronal network integrity and cell survival

    NASA Astrophysics Data System (ADS)

    Benotmane, Rafi

    During orbital or interplanetary space flights, astronauts are exposed to cosmic radiations and microgravity. This study aimed at assessing the effect of these combined conditions on neuronal network density, cell morphology and survival, using well-connected mouse cortical neuron cultures. To this end, neurons were exposed to acute low and high doses of low LET (X-rays) radiation or to chronic low dose-rate of high LET neutron irradiation (Californium-252), under the simulated microgravity generated by the Random Positioning Machine (RPM, Dutch space). High content image analysis of cortical neurons positive for the neuronal marker βIII-tubulin unveiled a reduced neuronal network integrity and connectivity, and an altered cell morphology after exposure to acute/chronic radiation or to simulated microgravity. Additionally, in both conditions, a defect in DNA-repair efficiency was revealed by an increased number of γH2AX-positive foci, as well as an increased number of Annexin V-positive apoptotic neurons. Of interest, when combining both simulated space conditions, we noted a synergistic effect on neuronal network density, neuronal morphology, cell survival and DNA repair. Furthermore, these observations are in agreement with preliminary gene expression data, revealing modulations in cytoskeletal and apoptosis-related genes after exposure to simulated microgravity. In conclusion, the observed in vitro changes in neuronal network integrity and cell survival induced by space simulated conditions provide us with mechanistic understanding to evaluate health risks and the development of countermeasures to prevent neurological disorders in astronauts over long-term space travels. Acknowledgements: This work is supported partly by the EU-FP7 projects CEREBRAD (n° 295552)

  4. Spatiotemporal pattern of neuronal injury induced by DFP in rats: A model for delayed neuronal cell death following acute OP intoxication

    SciTech Connect

    Li Yonggang; Lein, Pamela J.; Liu Cuimei; Bruun, Donald A.; Tewolde, Teclemichael; Ford, Gregory; Ford, Byron D.

    2011-06-15

    Organophosphate (OP) neurotoxins cause acute cholinergic toxicity and seizures resulting in delayed brain damage and persistent neurological symptoms. Testing novel strategies for protecting against delayed effects of acute OP intoxication has been hampered by the lack of appropriate animal models. In this study, we characterize the spatiotemporal pattern of cellular injury after acute intoxication with the OP diisopropylfluorophosphate (DFP). Adult male Sprague-Dawley rats received pyridostigmine (0.1 mg/kg, im) and atropine methylnitrate (20 mg/kg, im) prior to DFP (9 mg/kg, ip) administration. All DFP-treated animals exhibited moderate to severe seizures within minutes after DFP injection but survived up to 72 h. AChE activity was significantly depressed in the cortex, hippocampus, subcortical brain tissue and cerebellum at 1 h post-DFP injection and this inhibition persisted for up to 72 h. Analysis of neuronal injury by Fluoro-Jade B (FJB) labeling revealed delayed neuronal cell death in the hippocampus, cortex, amygdala and thalamus, but not the cerebellum, starting at 4 h and persisting until 72 h after DFP treatment, although temporal profiles varied between brain regions. At 24 h post-DFP injection, the pattern of FJB labeling corresponded to TUNEL staining in most brain regions, and FJB-positive cells displayed reduced NeuN immunoreactivity but were not immunopositive for astrocytic (GFAP), oligodendroglial (O4) or macrophage/microglial (ED1) markers, demonstrating that DFP causes a region-specific delayed neuronal injury mediated in part by apoptosis. These findings indicate the feasibility of this model for testing neuroprotective strategies, and provide insight regarding therapeutic windows for effective pharmacological intervention following acute OP intoxication. - Research Highlights: > DFP induced neuronal FJB labeling starting at 4-8 h after treatment > The pattern of DFP-induced FJB labeling closely corresponded to TUNEL staining > FJB

  5. Acute upregulation of neuronal mitochondrial type-1 cannabinoid receptor and it's role in metabolic defects and neuronal apoptosis after TBI.

    PubMed

    Xu, Zhen; Lv, Xiao-Ai; Dai, Qun; Ge, Yu-Qing; Xu, Jie

    2016-08-02

    Metabolic defects and neuronal apoptosis initiated by traumatic brain injury (TBI) contribute to subsequent neurodegeneration. They are all regulated by mechanisms centered around mitochondrion. Type-1 cannabinoid receptor (CB1) is a G-protein coupled receptor (GPCR) enriched on neuronal plasma membrane. Recent evidences point to the substantial presence of CB1 receptors on neuronal mitochondrial outer membranes (mtCB1) and the activation of mtCB1 influences aerobic respiration via inhibiting mitochondrial cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)/complex I pathway. The expression and role of neuronal mtCB1 under TBI are unknown. Using TBI models of cultured neurons, wild type and CB1 knockout mice, we found mtCB1 quickly upregulated after TBI. Activation of mtCB1 promoted metabolic defects accompanied with ATP shortage but protected neurons from apoptosis. Selective activation of plasma membrane CB1 showed no effects on neuronal metabolism and apoptosis. Activation of mtCB1 receptors inhibited mitochondrial cAMP/PKA/complex I and resulted in exacerbated metabolic defects accompanied with a higher ratio of ATP reduction to oxygen consumption decrease as well as neuronal apoptosis. Further research found the remarkable accumulation of protein kinase B (AKT) on neuronal mitochondria following TBI and the activation of mtCB1 upregulated mitochondrial AKT/complex V activity. Upregulation of mitochondrial AKT/complex V activity showed anti-apoptosis effects and alleviated ATP shortage in metabolic defects. Taken together, we have identified mtCB1 quickly upregulate after TBI and a dual role the mtCB1 might play in metabolic defects and neuronal apoptosis initiated by TBI: the inhibition of mitochondrial cAMP/PKA/complex I aggravates metabolic defects, energy insufficiency as well as neuronal apoptosis, but the coactivation of mitochondrial AKT/complex V mitigates energy insufficiency and neuronal apoptosis.

  6. Electrophysiological profile of the new atypical neuroleptic, sertindole, on midbrain dopamine neurones in rats: acute and repeated treatment.

    PubMed

    Skarsfeldt, T

    1992-01-01

    Sertindole (Lundbeck code No. Lu 23-174) (1-[2-[4-[5-chloro-1-(4-fluorophenyl)-1H-indol-3-yl]-1-piperidinyl] ethyl]-2-imidazolidinone) is a new potential neuroleptic compound. After 3 weeks of treatment sertindole shows an extreme selectivity to inhibit the number of spontaneously active dopaminergic (DA) neurones in ventral tegmental area (VTA) while leaving the number of active DA neurones in substantia nigra pars compacta (SNC) unaffected. Acute injection of apomorphine or baclofen reverse the inhibition of activity seen after repeated treatment with sertindole. This suggests that sertindole induces a depolarization inactivation of the DA neurones. The depolarization inactivation is reversible since normal activity of DA neurones is found in both SNC and VTA after two weeks withdrawal from repeated treatment with a low dose with sertindole. One or two weeks administration of a high dose of sertindole induced only minor effects on the DA neurones in VTA; i.e., in order to obtain the depolarization inactivation sertindole requires 3 weeks of treatment as has also been reported for other neuroleptics. Three weeks of treatment with clozapine induces a selective inhibition of the active DA neurones in VTA but at much higher doses than seen with sertindole, while haloperidol induces a non-selective decrease of spontaneously active DA neurones in both areas. In acute electrophysiological experiments intravenous (i.v.) administration of sertindole--in contrast to both clozapine and haloperidol--neither reverse d-amphetamine- nor apomorphine-induced inhibition of the firing frequencies of DA neurones in SNC or in VTA. In addition, sertindole does not--even in high doses--increase the firing frequency of DA neurones in SNC or VTA.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Characterization of strychnine-sensitive glycine receptors in acutely isolated adult rat basolateral amygdala neurons.

    PubMed

    McCool, B A; Botting, S K

    2000-03-24

    Large concentrations of the beta-amino acid, taurine, can be found in many forebrain areas such as the basolateral amygdala, a portion of the limbic forebrain intimately associated with the regulation of fear/anxiety-like behaviors. In addition to its cytoprotective and osmoregulatory roles, taurine may also serve as an agonist at GABA(A)- and strychnine-sensitive glycine receptors. In this latter context, the present study demonstrates that application of taurine to acutely isolated neurons from the basolateral amygdala of adult rats causes significant alterations in resting membrane current, as measured by whole-cell patch clamp electrophysiology. Using standard pharmacological approaches, we find that currents gated by concentrations of taurine neurons, these two chloride channels are functionally expressed at comparable levels. Given that a number of clinically relevant compounds are associated with the regulation of GABA(A) receptors in this brain region, the presence of both strychnine-sensitive glycine receptors and their agonist, taurine, in the basolateral amygdala may suggest an important role for these receptors in the limbic forebrain of adult rats.

  8. Expression of mRNAs for PPT, CGRP, NF-200, and MAP-2 in cocultures of dissociated DRG neurons and skeletal muscle cells in administration of NGF or NT-3.

    PubMed

    Zhang, Weiwei; Li, Hao; Xing, Ziying; Yuan, Hongtu; Kindy, Mark S; Li, Zhenzhong

    2012-07-05

    Both neurotrophins (NTs) and target skeletal muscle (SKM) cells are essential for the maintenance of the function of neurons and nerve-muscle communication. However, much less is known about the association of target SKM cells with distinct NTs on the expression of mRNAs for preprotachykinin (PPT), calcitonin-gene related peptide (CGRP), neurofilament 200 (NF-200), and microtubule associated protein 2 (MAP-2) in dorsal root ganglion (DRG) sensory neurons. In the present study, a neuromuscular coculture model of dissociated dorsal root ganglion (DRG) neurons and SKM cells was established. The morphology of DRG neurons and SKM cells in coculture was observed with an inverted phase contrast microscope. The effects of nerve growth factor (NGF) or neurotrophin-3 (NT-3) on the expression of mRNAs for PPT, CGRP, NF-200, and MAP-2 was analyzed by real time-PCR assay. The morphology of DRG neuronal cell bodies and SKM cells in neuromuscular coculture at different conditions was similar. The neurons presented evidence of dense neurite outgrowth in the presence of distinct NTs in neuromuscular cocultures. NGF and NT-3 increased mRNA levels of PPT, CGRP, and NF-200, but not MAP-2, in neuromuscular cocultures. These results offer new clues towards a better understanding of the association of target SKM cells with distinct NTs on the expression of mRNAs for PPT, CGRP, NF-200 and MAP-2, and implicate the association of target SKM cells and NTs with DRG sensory neuronal phenotypes.

  9. Mu-Opioid Stimulation in Rat Prefrontal Cortex Engages Hypothalamic Orexin/Hypocretin-Containing Neurons, and Reveals Dissociable Roles of Nucleus Accumbens and Hypothalamus in Cortically Driven Feeding

    PubMed Central

    Mena, Jesus D.; Selleck, Ryan A.

    2013-01-01

    Mu-opioid receptor (μOR) stimulation within ventral medial prefrontal cortex (vmPFC) induces feeding and hyperactivity, resulting possibly from recruitment of glutamate signaling in multiple vmPFC projection targets. We tested this hypothesis by analyzing Fos expression in vmPFC terminal fields after intra-vmPFC μOR stimulation, and by examining of the impact of glutamate receptor blockade in two feeding-related targets of vmPFC, the lateral-perifornical hypothalamic area (LH-PeF) and nucleus accumbens shell (Acb shell), upon behavioral effects elicited by intra-vmPFC μOR stimulation in rats. Intra-vmPFC infusion of the μOR agonist, DAMGO, provoked Fos expression in the dorsomedial sector of tuberal hypothalamus (including the perifornical area) and increased the percentage of Fos-expressing hypocretin/orexin-immunoreactive neurons in these zones. NMDA receptor blockade in the LH-PeF nearly eliminated intra-vmPFC DAMGO-induced food intake without altering DAMGO-induced hyperactivity. In contrast, blocking AMPA-type glutamate receptors within the Acb shell (the feeding-relevant subtype in this structure) antagonized intra-vmPFC DAMGO-induced hyperlocomotion but enhanced food intake. Intra-vmPFC DAMGO also elevated the breakpoint for sucrose-reinforced progressive-ratio responding; this effect was significantly enhanced by concomitant AMPA blockade in the Acb shell. Conversely, intra-Acb shell AMPA stimulation reduced breakpoint and increased nonspecific responding on the inactive lever. These data indicate intra-vmPFC μOR signaling jointly modulates appetitive motivation and generalized motoric activation through functionally dissociable vmPFC projection targets. These findings may shed light on the circuitry underlying disorganized appetitive responses in psychopathology; e.g., binge eating and opiate or alcohol abuse, disorders in which μORs and aberrant cortical activation have been implicated. PMID:24259576

  10. Dissociative disorders.

    PubMed

    Kihlstrom, John F

    2005-01-01

    The dissociative disorders, including "psychogenic" or "functional" amnesia, fugue, dissociative identity disorder (DID, also known as multiple personality disorder), and depersonalization disorder, were once classified, along with conversion disorder, as forms of hysteria. The 1970s witnessed an "epidemic" of dissociative disorder, particularly DID, which may have reflected enthusiasm for the diagnosis more than its actual prevalence. Traditionally, the dissociative disorders have been attributed to trauma and other psychological stress, but the existing evidence favoring this hypothesis is plagued by poor methodology. Prospective studies of traumatized individuals reveal no convincing cases of amnesia not attributable to brain insult, injury, or disease. Treatment generally involves recovering and working through ostensibly repressed or dissociated memories of trauma; at present, there are few quantitative or controlled outcome studies. Experimental studies are few in number and have focused largely on state-dependent and implicit memory. Depersonalization disorder may be in line for the next "epidemic" of dissociation.

  11. Dissociative amnesia.

    PubMed

    Staniloiu, Angelica; Markowitsch, Hans J

    2014-08-01

    Dissociative amnesia is one of the most enigmatic and controversial psychiatric disorders. In the past two decades, interest in the understanding of its pathophysiology has surged. In this report, we review new data about the epidemiology, neurobiology, and neuroimaging of dissociative amnesia and show how advances in memory research and neurobiology of dissociation inform proposed pathogenetic models of the disorder. Dissociative amnesia is characterised by functional impairment. Additionally, preliminary data suggest that affected people have an increased and possibly underestimated suicide risk. The prevalence of dissociative amnesia differs substantially across countries and populations. Symptoms and disease course also vary, indicating a possibly heterogeneous disorder. The accompanying clinical features differ across cultural groups. Most dissociative amnesias are retrograde, with memory impairments mainly involving the episodic-autobiographical memory domain. Anterograde dissociative amnesia occurring without significant retrograde memory impairments is rare. Functional neuroimaging studies of dissociative amnesia with prevailing retrograde memory impairments show changes in the network that subserves autobiographical memory. At present, no evidence-based treatments are available for dissociative amnesia and no broad framework exists for its rehabilitation. Further research is needed into its neurobiology, course, treatment options, and strategies to improve differential diagnoses.

  12. Acute psychological reactions in assault victims of non-domestic violence: peritraumatic dissociation, post-traumatic stress disorder, anxiety and depression.

    PubMed

    Johansen, Venke A; Wahl, Astrid K; Eilertsen, Dag Erik; Hanestad, Berit R; Weisaeth, Lars

    2006-01-01

    The aims of this study were to investigate acute and subacute post-traumatic reactions in victims of physical non-domestic violence. A Norwegian sample of 138 physically assaulted victims was interviewed and a questionnaire was completed. The following areas were examined: the frequency and intensity of acute and subacute psychological reactions such as peritraumatic dissociation (PD), post-traumatic stress disorder (PTSD) and anxiety and depression; the relationship between several psychological reactions; the relationship between psychological reactions and level of physical injury, perceived life threat, and potential of severe physical injury, and the relationship between psychological reactions and socio-demographic variables. The following distress reactions were measured retrospectively: PD, PTSD, and anxiety and depression. Thirty-three per cent of the victims scored as probable PTSD cases according to the Post Traumatic Symptoms Scale 10 (PTSS-10); the corresponding Impact of Event Scale-15 (IES-15) score identified prevalence of 34% respectively. Forty-four per cent scored as cases with probable anxiety and depression, according to the Hopkins Symptom Check List 25 (HSCL-25). Severity of perceived threat predicted higher scores on all measures of psychological reactions. There were no statistically significant differences between acute and subacute groups on PD, PTSS-10, IES-15, IES-22 and HSCL-25 according to measured means (and standard deviations) and occurrence of probable cases and risk level cases. The results showed no connection between severity of physical injury and caseness. The acute psychological impairment that results from assault violence may have a deleterious effect on the mental health of victims.

  13. Electrophysiological and Morphological Characterization of Neuronal Microcircuits in Acute Brain Slices Using Paired Patch-Clamp Recordings

    PubMed Central

    Qi, Guanxiao; Radnikow, Gabriele; Feldmeyer, Dirk

    2015-01-01

    The combination of patch clamp recordings from two (or more) synaptically coupled neurons (paired recordings) in acute brain slice preparations with simultaneous intracellular biocytin filling allows a correlated analysis of their structural and functional properties. With this method it is possible to identify and characterize both pre- and postsynaptic neurons by their morphology and electrophysiological response pattern. Paired recordings allow studying the connectivity patterns between these neurons as well as the properties of both chemical and electrical synaptic transmission. Here, we give a step-by-step description of the procedures required to obtain reliable paired recordings together with an optimal recovery of the neuron morphology. We will describe how pairs of neurons connected via chemical synapses or gap junctions are identified in brain slice preparations. We will outline how neurons are reconstructed to obtain their 3D morphology of the dendritic and axonal domain and how synaptic contacts are identified and localized. We will also discuss the caveats and limitations of the paired recording technique, in particular those associated with dendritic and axonal truncations during the preparation of brain slices because these strongly affect connectivity estimates. However, because of the versatility of the paired recording approach it will remain a valuable tool in characterizing different aspects of synaptic transmission at identified neuronal microcircuits in the brain. PMID:25650985

  14. Ovarian hormone deficiency reduces intrinsic excitability and abolishes acute estrogen sensitivity in hippocampal CA1 pyramidal neurons

    PubMed Central

    Wu, Wendy W.; Adelman, John P.; Maylie, James

    2011-01-01

    Premature and uncompensated loss of ovarian hormones following ovariectomy (OVX) elevates the risks of cognitive impairment and dementia. These risks are prevented with estrogen (E2)-containing hormone replacement therapy initiated shortly following OVX but not after substantial delay. Currently the cellular bases underlying these clinical findings are unknown. At the cellular level, intrinsic membrane properties regulate the efficiency of synaptic inputs to initiate output action potentials (APs), thereby affecting neuronal communication hence cognitive processing. This study tested the hypothesis that in CA1 pyramidal neurons, intrinsic membrane properties and their acute regulation by E2 require ovarian hormones for maintenance. Whole-cell current clamp recordings were performed on neurons from ~7 months old OVX rats that experienced either short-term (10 days, control OVX) or long-term (5 months, OVXLT) ovarian hormone deficiency. The results reveal that long-term hormone deficiency reduced intrinsic membrane excitability (IE) as measured by the number of evoked action potentials (APs) and firing duration for a given current injection. This was accompanied by AP broadening, an increased slow afterhyperpolarization (sAHP), and faster accumulation of NaV channel inactivation during repetitive firing. In the control OVX neurons, E2 acutely increased IE and reduced the sAHP. In contrast, acute regulation of IE by E2 was absent in the OVXLT neurons. Since the degree of IE of hippocampal pyramidal neurons is positively related with hippocampus-dependent learning ability, and modulation of IE is observed following successful learning, these findings provide a framework for understanding hormone deficiency-related cognitive impairment and the critical window for therapy initiation. PMID:21325532

  15. Genome-Wide Expression Analysis Reveals Diverse Effects of Acute Nicotine Exposure on Neuronal Function-Related Genes and Pathways

    PubMed Central

    Wang, Ju; Cui, Wenyan; Wei, Jinxue; Sun, Dongxiao; Gutala, Ramana; Gu, Jun; Li, Ming D.

    2011-01-01

    Previous human and animal studies demonstrate that acute nicotine exposure has complicated influences on the function of the nervous system, which may lead to long-lasting effects on the behavior and physiology of the subject. To determine the genes and pathways that might account for long-term changes after acute nicotine exposure, a pathway-focused oligoarray specifically designed for drug addiction research was used to assess acute nicotine effect on gene expression in the neuron-like SH-SY5Y cells. Our results showed that 295 genes involved in various biological functions were differentially regulated by 1 h of nicotine treatment. Among these genes, the expression changes of 221 were blocked by mecamylamine, indicating that the majority of nicotine-modulated genes were altered through the nicotinic acetylcholine receptors (nAChRs)-mediated signaling process. We further identified 14 biochemical pathways enriched among the nicotine-modulated genes, among which were those involved in neural development/synaptic plasticity, neuronal survival/death, immune response, or cellular metabolism. In the genes significantly regulated by nicotine but blocked by mecamylamine, 13 enriched pathways were detected. Nine of these pathways were shared with those enriched in the genes regulated by nicotine, including neuronal function-related pathways such as glucocorticoid receptor signaling, p38 MAPK signaling, PI3K/AKT signaling, and PTEN signaling, implying that nAChRs play important roles in the regulation of these biological processes. Together, our results not only provide insights into the mechanism underlying the acute response of neuronal cells to nicotine but also provide clues to how acute nicotine exposure exerts long-term effects on the nervous system. PMID:21556275

  16. Acute neurotoxic effects of mancozeb and maneb in mesencephalic neuronal cultures are associated with mitochondrial dysfunction.

    PubMed

    Domico, Lisa M; Zeevalk, Gail D; Bernard, Laura P; Cooper, Keith R

    2006-09-01

    Recent studies suggest that exposure to agrochemicals may contribute to the development of idiopathic Parkinson's disease. Maneb (MB), a widely used Mn-containing ethylene-bis-dithiocarbamate (EBDC) fungicide, has been implicated in selective dopaminergic neurotoxicity. In this study, we examine the potential neurotoxicity of mancozeb (MZ), a widely used EBDC fungicide that is structurally similar to MB, but contains both Zn and Mn. Primary mesencephalic cells isolated from Sprague-Dawley embryonic day 15 rat embryos were exposed in vitro to either MZ or MB to compare their cytotoxic potential. Exposure to 10-120 microM MZ or MB for 24h resulted in a dose-dependent toxicity in both the dopamine (DA) and GABA mesencephalic populations as assessed by a functional assay for high affinity transporter activity. Consistent with this, cell viability as well as tyrosine hydroxylase-positive neurons decreased with increasing doses of MZ or MB. Toxic potencies for MZ and MB were similar and no difference in sensitivity between the DA and GABA populations was observed with the fungicides. Exposure to ethylene thiourea, the major metabolite of either MZ or MB, was not toxic, implicating the parent compound in toxicity. Both the organic and Mn metal components of the fungicides were found to contribute to toxicity. Non-toxic exposures to the fungicides decreased ATP levels in a dose-dependent manner suggesting impairment of energy metabolism. In whole mitochondrial preparations isolated from adult rat brains, MZ and MB inhibited NADH-linked state 3 respiration. Mild to moderate mitochondrial uncoupling was also observed in response to the fungicides. In conclusion, our findings indicate that acute exposure to high doses of MZ and MB produce equipotent toxic effects in both DA and GABA neurons that may be associated with perturbations in mitochondrial respiration.

  17. Examination of the influence of leptin and acute metabolic challenge on RFRP-3 neurons of mice in development and adulthood

    PubMed Central

    Poling, Matthew C.; Shieh, Morris P.; Munaganuru, Nagambika; Luo, Elena; Kauffman, Alexander S.

    2014-01-01

    Background The neuropeptide RFamide-related peptide-3 (RFRP-3; mammalian ortholog to GnIH) can inhibit LH release and increases feeding, but the regulation and development of RFRP-3 neurons remains poorly characterized, especially in mice. Methods and Results We first confirmed that peripheral injections of murine RFRP-3 peptide could markedly suppress luteinizing hormone secretion in adult mice, as in other species. Second, given RFRP-3′s reported orexigenic properties, we performed double-label in situ hybridization for metabolic genes in Rfrp neurons of mice. While Rfrp neurons did not readily co-express NPY, TRH, or MC4R, a small subset of Rfrp neurons did express leptin receptor in both sexes. Surprisingly, we identified no changes in Rfrp expression or neuronal activation in adult mice after acute fasting. However, we determined that Rfrp mRNA levels in the DMN were significantly reduced in adult Obese (Ob) mice of both sexes. Given the lower Rfrp levels observed in adult Ob mice, we asked whether leptin might also regulate RFRP-3 neuron development. Rfrp gene expression changed markedly over juvenile development, correlating with the timing of the juvenile “leptin surge” known to govern hypothalamic feeding circuit development. However, the dramatic developmental changes in juvenile Rfrp expression did not appear to be leptin-driven, as the pattern and timing of Rfrp neuron development were unaltered in Ob juveniles. Conclusion Leptin status modulates RFRP-3 expression in adulthood, but is not required for normal development of the RFRP-3 system. Leptin's regulation of adult RFRP-3 neurons likely occurs via primarily indirect signaling, and may be secondary to obesity, as only a small subset of RFRP-3 neurons express LepRb. PMID:25378037

  18. Dissociative experiences on ice--peritraumatic and trait dissociation during the cold pressor test.

    PubMed

    Giesbrecht, Timo; Smeets, Tom; Merckelbach, Harald

    2008-01-15

    The present study investigated the relationship between trait dissociation and peritraumatic dissociation during acute painful stimulation. In a sample of 70 undergraduate students, peritraumatic dissociation was induced by means of a cold pressor test, which basically consists of participants holding an arm in ice water for as long as possible. Results indicate that heightened trait dissociation scores were related to shorter durations that participants could sustain the task. However, trait dissociation was not associated with increases in acute dissociative symptoms (i.e., peritraumatic dissociation). These findings are in sharp contrast to the defensive function ascribed to both types of dissociation and also the commonly held assumption that peritraumatic and trait dissociation are intimately linked.

  19. Influences of nanoparticle zinc oxide on acutely isolated rat hippocampal CA3 pyramidal neurons.

    PubMed

    Zhao, Jingxia; Xu, Lanju; Zhang, Tao; Ren, Guogang; Yang, Zhuo

    2009-03-01

    The effects of zinc oxide nanoparticles (nano-ZnO) on the properties of voltage-dependent sodium, potassium currents and evoked action potentials were studied in acutely isolated rat hippocampal CA3 pyramidal neurons at postnatal ages of 10-14 days rats using the whole-cell patch-clamp technique. The results indicated that: (1) in the present of final concentration of 10(-4)g/ml nano-ZnO, the current-voltage curve of sodium current (I(Na)) was decreased, and the peak amplitudes of I(Na) were increased considerably from -50 to +20mV (p<0.05). Meanwhile, the inactivation and the recovery from inactivation of I(Na) were also promoted by the nano-ZnO solution (10(-4)g/ml) (p<0.01). However, the steady-state activation curve of I(Na) was not shifted by the nano-ZnO. (2) The amplitudes of transient outward potassium current (I(A)) were increased by the nano-ZnO solution (10(-4)g/ml), while the current-voltage curve of delayed rectifier potassium current (I(K)) was significantly increased from +20 to +90mV (p<0.05). However, it is apparent that the nano-ZnO solution did not shift the steady-state activation curve of I(A) and I(K), and neither had significant effects on the inactivation and the recovery from inactivation of I(A). (3) Peak amplitude and overshoot of the evoked single action potential were increased and half-width was diminished in the presence of the 10(-4)g/ml nano-ZnO solution (p<0.05). Simultaneously, a prolonged depolarizing current injection enhanced (p<0.05) repetitive firing evoked firing rate. These results suggested that 10(-4)g/ml nano-ZnO solution can lead to an enhancement in the current amplitudes of I(Na) and I(K) by increasing the opening number of sodium channels, delaying rectifier potassium channels, and enhancing the excitability of neurons, which lead to Na(+) influx and the accumulation of intracellular Na(+), as well as K(+) efflux plus the loss of cytoplasmic K(+). These may disturb the ionic homeostasis and the physiological

  20. Exploring psychotic symptoms: a comparison of motor related neuronal activation during and after acute psychosis

    PubMed Central

    2012-01-01

    Background Delusions and hallucinations are classic positive symptoms of schizophrenia. A contemporary cognitive theory called the ‘forward output model’ suggests that the misattribution of self-generated actions may underlie some of these types of symptoms, such as delusions of control – the experience of self-generated action being controlled by an external agency. In order to examine the validity of this suggestion, we performed a longitudinal functional magnetic resonance imaging (fMRI) study examining neuronal activation associated with motor movement during acute psychosis. Methods We studied brain activation using fMRI during a motor task in 11 patients with schizophrenia and 9 healthy controls. The patient group was tested at two time points separated by 6–8 weeks. Results At initial testing, the patient group had a mean Positive and Negative Syndrome Scale score of 56.3, and showed significantly increased activation within the left inferior parietal lobe (IPL) compared to controls. Patients reported significantly decreased positive symptoms at 6–8 week followup and IPL activation had returned to normal. Our results demonstrate that first-rank positive symptoms are associated with hyperactivation in the secondary somatosensory cortex (IPL). Conclusions These findings lend further credence to the theory that a dysfunction in the sensory feedback system located in the IPL, and which is thought to underlie our sense of agency, may contribute to the aetiology of delusions of control. PMID:22871335

  1. Acute intravenous administration of dietary constituent theanine suppresses noxious neuronal transmission of trigeminal spinal nucleus caudalis in rats.

    PubMed

    Takehana, Shiori; Kubota, Yoshiko; Uotsu, Nobuo; Yui, Kei; Shimazu, Yoshihito; Takeda, Mamoru

    2017-03-15

    Theanine is a non-dietary amino acid linked to the modulation of synaptic transmission in the central nervous system, although the acute effects of theanine in vivo, particularly on nociceptive transmission in the trigeminal system, remain to be determined. The present study investigated whether acute intravenous theanine administration to rats attenuates the excitability of wide dynamic range (WDR) spinal trigeminal nucleus caudalis (SpVc) neurons in response to nociceptive and non-nociceptive mechanical stimulation in vivo. Extracellular single unit recordings were made from 15 SpVc neurons in response to orofacial mechanical stimulation of pentobarbital-anesthetized rats, and responses to non-noxious and noxious mechanical stimuli were analyzed. The mean firing frequency of SpVc WDR neurons in response to all mechanical stimuli was dose-dependently inhibited by theanine (10, 50, and 100mM, i.v.) with the maximum inhibition of discharge frequency reached within 5min. These inhibitory effects were reversed after approximately 10min. The relative magnitude of theanine's inhibition of SpVc WDR neuronal discharge frequency was significantly greater for noxious than non-noxious stimulation. Iontophoretic application of l-glutamate induced the mean firing frequency of SpVc WDR neuron responding to noxious mechanical stimulation was also inhibited by intravenous administration of 100mM theanine. These results suggest that acute intravenous theanine administration suppresses glutaminergic noxious synaptic transmission in the SpVc, implicating theanine as a potential complementary and alternative therapeutic agent for the treatment of trigeminal nociceptive pain.

  2. Contrasting alterations to synaptic and intrinsic properties in upper-cervical superficial dorsal horn neurons following acute neck muscle inflammation

    PubMed Central

    2014-01-01

    Background Acute and chronic pain in axial structures, like the back and neck, are difficult to treat, and have incidence as high as 15%. Surprisingly, most preclinical work on pain mechanisms focuses on cutaneous structures in the limbs and animal models of axial pain are not widely available. Accordingly, we developed a mouse model of acute cervical muscle inflammation and assessed the functional properties of superficial dorsal horn (SDH) neurons. Results Male C57/Bl6 mice (P24-P40) were deeply anaesthetised (urethane 2.2 g/kg i.p) and the rectus capitis major muscle (RCM) injected with 40 μl of 2% carrageenan. Sham animals received vehicle injection and controls remained anaesthetised for 2 hrs. Mice in each group were sacrificed at 2 hrs for analysis. c-Fos staining was used to determine the location of activated neurons. c-Fos labelling in carrageenan-injected mice was concentrated within ipsilateral (87% and 63% of labelled neurons in C1 and C2 segments, respectively) and contralateral laminae I - II with some expression in lateral lamina V. c-Fos expression remained below detectable levels in control and sham animals. In additional experiments, whole cell recordings were obtained from visualised SDH neurons in transverse slices in the ipsilateral C1 and C2 spinal segments. Resting membrane potential and input resistance were not altered. Mean spontaneous EPSC amplitude was reduced by ~20% in neurons from carrageenan-injected mice versus control and sham animals (20.63 ± 1.05 vs. 24.64 ± 0.91 and 25.87 ± 1.32 pA, respectively). The amplitude (238 ± 33 vs. 494 ± 96 and 593 ± 167 pA) and inactivation time constant (12.9 ± 1.5 vs. 22.1 ± 3.6 and 15.3 ± 1.4 ms) of the rapid A type potassium current (IAr), the dominant subthreshold current in SDH neurons, were reduced in carrageenan-injected mice. Conclusions Excitatory synaptic drive onto, and important intrinsic properties (i.e., IAr) within SDH neurons are

  3. Contributions of Bcl-xL to acute and long term changes in bioenergetics during neuronal plasticity.

    PubMed

    Jonas, Elizabeth A

    2014-08-01

    Mitochondria manufacture and release metabolites and manage calcium during neuronal activity and synaptic transmission, but whether long term alterations in mitochondrial function contribute to the neuronal plasticity underlying changes in organism behavior patterns is still poorly understood. Although normal neuronal plasticity may determine learning, in contrast a persistent decline in synaptic strength or neuronal excitability may portend neurite retraction and eventual somatic death. Anti-death proteins such as Bcl-xL not only provide neuroprotection at the neuronal soma during cell death stimuli, but also appear to enhance neurotransmitter release and synaptic growth and development. It is proposed that Bcl-xL performs these functions through its ability to regulate mitochondrial release of bioenergetic metabolites and calcium, and through its ability to rapidly alter mitochondrial positioning and morphology. Bcl-xL also interacts with proteins that directly alter synaptic vesicle recycling. Bcl-xL translocates acutely to sub-cellular membranes during neuronal activity to achieve changes in synaptic efficacy. After stressful stimuli, pro-apoptotic cleaved delta N Bcl-xL (ΔN Bcl-xL) induces mitochondrial ion channel activity leading to synaptic depression and this is regulated by caspase activation. During physiological states of decreased synaptic stimulation, loss of mitochondrial Bcl-xL and low level caspase activation occur prior to the onset of long term decline in synaptic efficacy. The degree to which Bcl-xL changes mitochondrial membrane permeability may control the direction of change in synaptic strength. The small molecule Bcl-xL inhibitor ABT-737 has been useful in defining the role of Bcl-xL in synaptic processes. Bcl-xL is crucial to the normal health of neurons and synapses and its malfunction may contribute to neurodegenerative disease.

  4. The expression of amphetamine sensitization is dissociable from anxiety and aversive memory: Effect of an acute injection of amphetamine.

    PubMed

    Gatica, Rafael Ignacio; Pérez-Valenzuela, Enzo; Sierra-Mercado, Demetrio; Fuentealba, José Antonio

    2017-01-18

    The repeated administration of amphetamine can lead to locomotor sensitization. Although the repeated administration of amphetamine has been associated with anxiety and impaired working memory, it is uncertain if expression of amphetamine sensitization is associated with modifications of emotional memories. To address this issue, rats were injected once daily with amphetamine for five consecutive days (1.5mg/kg). After four days of withdrawal, rats were delivered an acute amphetamine injection to assess the expression of sensitization. A single exposure to an elevated plus maze (EPM), 24h after the last injection of amphetamine, showed that amphetamine sensitization is not accompanied by anxiety. Next, aversive memory was assessed using an 11day inter-trial interval between the EPM Trial 1 and EPM Trial 2. Rats administered with saline showed a percentage of open arms time (% OAT) in Trial 2 that was comparable to Trial 1, demonstrating a reduction in the retrieval of aversive memory. However, rats sensitized after the EPM Trial 1 showed a significant decrease in the % OAT in Trial 2. Importantly, a decrease in the % OAT in Trial 2 compared to Trial 1 was also observed after a single injection of amphetamine 24h before Trial 2. These results show a facilitation in the retrieval of aversive memory, and suggest that a previous amphetamine injection is enough to produce a protracted activation of neural circuits necessary for the retrieval of aversive memory.

  5. Morphofunctional alterations in ventral tegmental area dopamine neurons in acute and prolonged opiates withdrawal. A computational perspective.

    PubMed

    Enrico, P; Migliore, M; Spiga, S; Mulas, G; Caboni, F; Diana, M

    2016-05-13

    Dopamine (DA) neurons of the ventral tegmental area (VTA) play a key role in the neurobiological basis of goal-directed behaviors and addiction. Morphine (MOR) withdrawal induces acute and long-term changes in the morphology and physiology of VTA DA cells, but the mechanisms underlying these modifications are poorly understood. Because of their predictive value, computational models are a powerful tool in neurobiological research, and are often used to gain further insights and deeper understanding on the molecular and physiological mechanisms underlying the development of various psychiatric disorders. Here we present a biophysical model of a DA VTA neuron based on 3D morphological reconstruction and electrophysiological data, showing how opiates withdrawal-driven morphological and electrophysiological changes could affect the firing rate and discharge pattern. The model findings suggest how and to what extent a change in the balance of GABA/GLU inputs can take into account the experimentally observed hypofunction of VTA DA neurons during acute and prolonged withdrawal, whereas morphological changes may play a role in the increased excitability of VTA DA cell to opiate administration observed during opiate withdrawal.

  6. The effects of acute alcohol exposure on the response properties of neurons in visual cortex area 17 of cats

    SciTech Connect

    Chen Bo; Xia Jing; Li Guangxing; Zhou Yifeng

    2010-03-15

    Physiological and behavioral studies have demonstrated that a number of visual functions such as visual acuity, contrast sensitivity, and motion perception can be impaired by acute alcohol exposure. The orientation- and direction-selective responses of cells in primary visual cortex are thought to participate in the perception of form and motion. To investigate how orientation selectivity and direction selectivity of neurons are influenced by acute alcohol exposure in vivo, we used the extracellular single-unit recording technique to examine the response properties of neurons in primary visual cortex (A17) of adult cats. We found that alcohol reduces spontaneous activity, visual evoked unit responses, the signal-to-noise ratio, and orientation selectivity of A17 cells. In addition, small but detectable changes in both the preferred orientation/direction and the bandwidth of the orientation tuning curve of strongly orientation-biased A17 cells were observed after acute alcohol administration. Our findings may provide physiological evidence for some alcohol-related deficits in visual function observed in behavioral studies.

  7. Cellular NAD depletion and decline of SIRT1 activity play critical roles in PARP-1-mediated acute epileptic neuronal death in vitro.

    PubMed

    Wang, Shengjun; Yang, Xue; Lin, Youting; Qiu, Xiaoxue; Li, Hui; Zhao, Xiuhe; Cao, Lili; Liu, Xuewu; Pang, Yuejiu; Wang, Xuping; Chi, Zhaofu

    2013-10-16

    Intense poly(ADP-ribose) polymerase-1 (PARP-1) activation was implicated as a major cause of caspase-independent cell death in the hippocampal neuronal culture (HNC) model of acute acquired epilepsy (AE). The molecular mechanisms are quite complicated. The linkage among neuronal death, cellular nicotinamide adenine dinucleotide (NAD) levels, apoptosis-inducing factor (AIF) translocation, SIRT1 expression and activity were investigated here. The results showed that PARP-1 over-activation caused by Mg²⁺-free stimuli led to cellular NAD depletion which could block AIF translocation from mitochondria to nucleus and attenuate neuronal death. Also, SIRT1 deacetylase activity was reduced by Mg²⁺-free treatment, accompanied by elevated ratio of neuronal death, which could be rescued by NAD repletion. These data demonstrated that cellular NAD depletion and decline of SIRT1 activity play critical roles in PARP-1-mediated epileptic neuronal death in the HNC model of acute AE.

  8. Toll-like receptor 4 signaling in neurons of trigeminal ganglion contributes to nociception induced by acute pulpitis in rats

    PubMed Central

    Lin, Jia-Ji; Du, Yi; Cai, Wen-Ke; Kuang, Rong; Chang, Ting; Zhang, Zhuo; Yang, Yong-Xiang; Sun, Chao; Li, Zhu-Yi; Kuang, Fang

    2015-01-01

    Pain caused by acute pulpitis (AP) is a common symptom in clinical settings. However, its underlying mechanisms have largely remained unknown. Using AP model, we demonstrated that dental injury caused severe pulp inflammation with up-regulated serum IL-1β. Assessment from head-withdrawal reflex thresholds (HWTs) and open-field test demonstrated nociceptive response at 1 day post injury. A consistent up-regulation of Toll-like receptor 4 (TLR4) in the trigeminal ganglion (TG) ipsilateral to the injured pulp was found; and downstream signaling components of TLR4, including MyD88, TRIF and NF-κB, and cytokines such as TNF-α and IL-1β, were also increased. Retrograde labeling indicated that most TLR4 positve neuron in the TG innnervated the pulp and TLR4 immunoreactivity was mainly in the medium and small neurons. Double labeling showed that the TLR4 expressing neurons in the ipsilateral TG were TRPV1 and CGRP positive, but IB4 negative. Furthermore, blocking TLR4 by eritoran (TLR4 antagonist) in TGs of the AP model significantly down-regulated MyD88, TRIF, NF-κB, TNF-α and IL-1β production and behavior of nociceptive response. Our findings suggest that TLR4 signaling in TG cells, particularly the peptidergic TRPV1 neurons, plays a key role in AP-induced nociception, and indicate that TLR4 signaling could be a potential therapeutic target for orofacial pain. PMID:26224622

  9. Effects of neuron-specific estrogen receptor (ER) α and ERβ deletion on the acute estrogen negative feedback mechanism in adult female mice.

    PubMed

    Cheong, Rachel Y; Porteous, Robert; Chambon, Pierre; Abrahám, István; Herbison, Allan E

    2014-04-01

    The negative feedback mechanism through which 17β-estradiol (E2) acts to suppress the activity of the GnRH neurons remains unclear. Using inducible and cell-specific genetic mouse models, we examined the estrogen receptor (ER) isoforms expressed by neurons that mediate acute estrogen negative feedback. Adult female mutant mice in which ERα was deleted from all neurons in the neonatal period failed to exhibit estrous cycles or negative feedback. Adult mutant female mice with neonatal neuronal ERβ deletion exhibited normal estrous cycles, but a failure of E2 to suppress LH secretion was seen in ovariectomized mice. Mutant mice with a GnRH neuron-selective deletion of ERβ exhibited normal cycles and negative feedback, suggesting no critical role for ERβ in GnRH neurons in acute negative feedback. To examine the adult roles of neurons expressing ERα, an inducible tamoxifen-based Cre-LoxP approach was used to ablate ERα from neurons that express calmodulin kinase IIα in adults. This resulted in mice with no estrous cycles, a normal increase in LH after ovariectomy, but an inability of E2 to suppress LH secretion. Finally, acute administration of ERα- and ERβ-selective agonists to adult ovariectomized wild-type mice revealed that activation of ERα suppressed LH secretion, whereas ERβ agonists had no effect. This study highlights the differences in adult reproductive phenotypes that result from neonatal vs adult ablation of ERα in the brain. Together, these experiments expand previous global knockout studies by demonstrating that neurons expressing ERα are essential and probably sufficient for the acute estrogen negative feedback mechanism in female mice.

  10. The acute phase of mild traumatic brain injury is characterized by a distance-dependent neuronal hypoactivity.

    PubMed

    Johnstone, Victoria P A; Shultz, Sandy R; Yan, Edwin B; O'Brien, Terence J; Rajan, Ramesh

    2014-11-15

    The consequences of mild traumatic brain injury (TBI) on neuronal functionality are only now being elucidated. We have now examined the changes in sensory encoding in the whisker-recipient barrel cortex and the brain tissue damage in the acute phase (24 h) after induction of TBI (n=9), with sham controls receiving surgery only (n=5). Injury was induced using the lateral fluid percussion injury method, which causes a mixture of focal and diffuse brain injury. Both population and single cell neuronal responses evoked by both simple and complex whisker stimuli revealed a suppression of activity that decreased with distance from the locus of injury both within a hemisphere and across hemispheres, with a greater extent of hypoactivity in ipsilateral barrel cortex compared with contralateral cortex. This was coupled with an increase in spontaneous output in Layer 5a, but only ipsilateral to the injury site. There was also disruption of axonal integrity in various regions in the ipsilateral but not contralateral hemisphere. These results complement our previous findings after mild diffuse-only TBI induced by the weight-drop impact acceleration method where, in the same acute post-injury phase, we found a similar depth-dependent hypoactivity in sensory cortex. This suggests a common sequelae of events in both diffuse TBI and mixed focal/diffuse TBI in the immediate post-injury period that then evolve over time to produce different long-term functional outcomes.

  11. The Acute Phase of Mild Traumatic Brain Injury Is Characterized by a Distance-Dependent Neuronal Hypoactivity

    PubMed Central

    Johnstone, Victoria P.A.; Shultz, Sandy R.; Yan, Edwin B.; O'Brien, Terence J.

    2014-01-01

    Abstract The consequences of mild traumatic brain injury (TBI) on neuronal functionality are only now being elucidated. We have now examined the changes in sensory encoding in the whisker-recipient barrel cortex and the brain tissue damage in the acute phase (24 h) after induction of TBI (n=9), with sham controls receiving surgery only (n=5). Injury was induced using the lateral fluid percussion injury method, which causes a mixture of focal and diffuse brain injury. Both population and single cell neuronal responses evoked by both simple and complex whisker stimuli revealed a suppression of activity that decreased with distance from the locus of injury both within a hemisphere and across hemispheres, with a greater extent of hypoactivity in ipsilateral barrel cortex compared with contralateral cortex. This was coupled with an increase in spontaneous output in Layer 5a, but only ipsilateral to the injury site. There was also disruption of axonal integrity in various regions in the ipsilateral but not contralateral hemisphere. These results complement our previous findings after mild diffuse-only TBI induced by the weight-drop impact acceleration method where, in the same acute post-injury phase, we found a similar depth-dependent hypoactivity in sensory cortex. This suggests a common sequelae of events in both diffuse TBI and mixed focal/diffuse TBI in the immediate post-injury period that then evolve over time to produce different long-term functional outcomes. PMID:24927383

  12. Diverse impact of acute and long-term extracellular proteolytic activity on plasticity of neuronal excitability

    PubMed Central

    Wójtowicz, Tomasz; Brzdąk, Patrycja; Mozrzymas, Jerzy W.

    2015-01-01

    Learning and memory require alteration in number and strength of existing synaptic connections. Extracellular proteolysis within the synapses has been shown to play a pivotal role in synaptic plasticity by determining synapse structure, function, and number. Although synaptic plasticity of excitatory synapses is generally acknowledged to play a crucial role in formation of memory traces, some components of neural plasticity are reflected by nonsynaptic changes. Since information in neural networks is ultimately conveyed with action potentials, scaling of neuronal excitability could significantly enhance or dampen the outcome of dendritic integration, boost neuronal information storage capacity and ultimately learning. However, the underlying mechanism is poorly understood. With this regard, several lines of evidence and our most recent study support a view that activity of extracellular proteases might affect information processing in neuronal networks by affecting targets beyond synapses. Here, we review the most recent studies addressing the impact of extracellular proteolysis on plasticity of neuronal excitability and discuss how enzymatic activity may alter input-output/transfer function of neurons, supporting cognitive processes. Interestingly, extracellular proteolysis may alter intrinsic neuronal excitability and excitation/inhibition balance both rapidly (time of minutes to hours) and in long-term window. Moreover, it appears that by cleavage of extracellular matrix (ECM) constituents, proteases may modulate function of ion channels or alter inhibitory drive and hence facilitate active participation of dendrites and axon initial segments (AISs) in adjusting neuronal input/output function. Altogether, a picture emerges whereby both rapid and long-term extracellular proteolysis may influence some aspects of information processing in neurons, such as initiation of action potential, spike frequency adaptation, properties of action potential and dendritic

  13. Resveratrol suppresses calcium-mediated microglial activation and rescues hippocampal neurons of adult rats following acute bacterial meningitis.

    PubMed

    Sheu, Ji-Nan; Liao, Wen-Chieh; Wu, Un-In; Shyu, Ling-Yuh; Mai, Fu-Der; Chen, Li-You; Chen, Mei-Jung; Youn, Su-Chung; Chang, Hung-Ming

    2013-03-01

    Acute bacterial meningitis (ABM) is a serious disease with severe neurological sequelae. The intense calcium-mediated microglial activation and subsequently pro-inflammatory cytokine release plays an important role in eliciting ABM-related oxidative damage. Considering resveratrol possesses significant anti-inflammatory and anti-oxidative properties, the present study aims to determine whether resveratrol would exert beneficial effects on hippocampal neurons following ABM. ABM was induced by inoculating Klebsiella pneumoniae into adult rats intraventricularly. The time-of-flight secondary ion mass spectrometry (TOF-SIMS), Griffonia simplicifolia isolectin-B4 (GSA-IB4) and ionized calcium binding adaptor molecule 1 (Iba1) immunohistochemistry, enzyme-linked immunosorbent assay as well as malondialdehyde (MDA) measurement were used to examine the calcium expression, microglial activation, pro-inflammatory cytokine level, and extent of oxidative stress, respectively. In ABM rats, strong calcium signaling associated with enhanced microglial activation was observed in hippocampus. Increased microglial expression was coincided with intense production of pro-inflammatory cytokines and oxidative damage. However, in rats receiving resveratrol after ABM, the calcium intensity, microglial activation, pro-inflammatory cytokine and MDA levels were all significantly decreased. Quantitative data showed that much more hippocampal neurons were survived in resveratrol-treated rats following ABM. As resveratrol successfully rescues hippocampal neurons from ABM by suppressing the calcium-mediated microglial activation, therapeutic use of resveratrol may act as a promising strategy to counteract the ABM-induced neurological damage.

  14. 5-HT1A receptor activation counteracted the effect of acute immobilization of noradrenergic neurons in the rat locus coeruleus.

    PubMed

    Rioja, José; Santín, Luis J; López-Barroso, Diana; Doña, Alicia; Ulzurrun, Eugenia; Aguirre, José A

    2007-01-22

    The aim of our study was to evaluate the effect of acute stress and the 5-HT(1A) receptor involvement in both, the hippocampus noradrenaline (NA) tissue levels and the c-Fos immunoreactivity (c-Fos-IR) in the catecholaminergic neurons of the locus coeruleus (LC). Double immunocytochemical staining of tyrosine hydroxilase (TH) and c-Fos protein combined with stereological techniques were used to study the specific cell activation in the LC neurons in five experimental groups (control group, immobilization (1h) group, 8-OH-DPAT group (8-OH-DPAT 0.3mg/kg, s.c.), DPAT+IMMO group (8-OH-DPAT 0.3mg/kg, s.c., 30' prior acute immobilization) and WAY+DPAT+IMMO group (WAY-100635 0.3mg/kg, s.c. and 8-OH-DPAT 0.3mg/kg, s.c., 45'and 30', respectively, before immobilization). The results showed that hippocampal NA tissue levels and c-Fos-IR in the TH positive neurons of the LC were significantly increased immediately and after 90', respectively, after the immobilization period. Pre-treatment with 8-OH-DPAT counteracted the effects induced by immobilization, but pre-treatment with WAY-100635 did not block the effects induced by 8-OH-DPAT. These results suggest that noradrenaline system is associated in a significant way with immobilization stress. The role of 5-HT(1A) receptor activation in this stress response is also discussed.

  15. Effects of acute treadmill running at different intensities on activities of serotonin and corticotropin-releasing factor neurons, and anxiety- and depressive-like behaviors in rats.

    PubMed

    Otsuka, Tomomi; Nishii, Ayu; Amemiya, Seiichiro; Kubota, Natsuko; Nishijima, Takeshi; Kita, Ichiro

    2016-02-01

    Accumulating evidence suggests that physical exercise can reduce and prevent the incidence of stress-related psychiatric disorders, including depression and anxiety. Activation of serotonin (5-HT) neurons in the dorsal raphe nucleus (DRN) is implicated in antidepressant/anxiolytic properties. In addition, the incidence and symptoms of these disorders may involve dysregulation of the hypothalamic-pituitary-adrenal axis that is initiated by corticotropin-releasing factor (CRF) neurons in the hypothalamic paraventricular nucleus (PVN). Thus, it is possible that physical exercise produces its antidepressant/anxiolytic effects by affecting these neuronal activities. However, the effects of acute physical exercise at different intensities on these neuronal activation and behavioral changes are still unclear. Here, we examined the activities of 5-HT neurons in the DRN and CRF neurons in the PVN during 30 min of treadmill running at different speeds (high speed, 25 m/min; low speed, 15m/min; control, only sitting on the treadmill) in male Wistar rats, using c-Fos/5-HT or CRF immunohistochemistry. We also performed the elevated plus maze test and the forced swim test to assess anxiety- and depressive-like behaviors, respectively. Acute treadmill running at low speed, but not high speed, significantly increased c-Fos expression in 5-HT neurons in the DRN compared to the control, whereas high-speed running significantly enhanced c-Fos expression in CRF neurons in the PVN compared with the control and low-speed running. Furthermore, low-speed running resulted in decreased anxiety- and depressive-like behaviors compared with high-speed running. These results suggest that acute physical exercise with mild and low stress can efficiently induce optimal neuronal activation that is involved in the antidepressant/anxiolytic effects.

  16. Scapholunate Dissociation.

    PubMed

    Ramponi, Denise; McSwigan, Tara

    2016-01-01

    Wrist injuries are a common complaint in the emergency setting. Any disruption of the anatomy of the carpal bones can impair hand function, leading to pain, weakness, and complications. One of the most common forms of carpal bone instability is scapholunate dissociation. This injury can lead to significant morbidity including avascular necrosis, impaired healing, limited function, and arthritis. These diagnostic findings may be subtle, thus identifying high-risk mechanisms of injury, and clinical manifestations will assist the emergency practitioner with early diagnosis and treatment of this high-risk injury.

  17. Stimulus-induced dissociation of neuronal firing rates and local field potential gamma power and its relationship to the blood oxygen level-dependent signal in macaque primary visual cortex

    PubMed Central

    Bartolo, M J; Gieselmann, M A; Vuksanovic, V; Hunter, D; Sun, L; Chen, X; Delicato, L S; Thiele, A

    2011-01-01

    The functional magnetic resonance imaging (fMRI) blood oxygenation level-dependent (BOLD) signal is regularly used to assign neuronal activity to cognitive function. Recent analyses have shown that the local field potential (LFP) gamma power is a better predictor of the fMRI BOLD signal than spiking activity. However, LFP gamma power and spiking activity are usually correlated, clouding the analysis of the neural basis of the BOLD signal. We show that changes in LFP gamma power and spiking activity in the primary visual cortex (V1) of the awake primate can be dissociated by using grating and plaid pattern stimuli, which differentially engage surround suppression and cross-orientation inhibition/facilitation within and between cortical columns. Grating presentation yielded substantial V1 LFP gamma frequency oscillations and significant multi-unit activity. Plaid pattern presentation significantly reduced the LFP gamma power while increasing population multi-unit activity. The fMRI BOLD activity followed the LFP gamma power changes, not the multi-unit activity. Inference of neuronal activity from the fMRI BOLD signal thus requires detailed a priori knowledge of how different stimuli or tasks activate the cortical network. PMID:22081989

  18. Fingolimod Limits Acute Aβ Neurotoxicity and Promotes Synaptic Versus Extrasynaptic NMDA Receptor Functionality in Hippocampal Neurons

    PubMed Central

    Joshi, Pooja; Gabrielli, Martina; Ponzoni, Luisa; Pelucchi, Silvia; Stravalaci, Matteo; Beeg, Marten; Mazzitelli, Sonia; Braida, Daniela; Sala, Mariaelvina; Boda, Enrica; Buffo, Annalisa; Gobbi, Marco; Gardoni, Fabrizio; Matteoli, Michela; Marcello, Elena; Verderio, Claudia

    2017-01-01

    Fingolimod, also known as FTY720, is an analogue of the sphingolipid sphingosine, which has been proved to be neuroprotective in rodent models of Alzheimer’s disease (AD). Several cellular and molecular targets underlying the neuroprotective effects of FTY720 have been recently identified. However, whether the drug directly protects neurons from toxicity of amyloid-beta (Aβ) still remains poorly defined. Using a combination of biochemical assays, live imaging and electrophysiology we demonstrate that FTY720 induces a rapid increase in GLUN2A-containing neuroprotective NMDARs on the surface of dendritic spines in cultured hippocampal neurons. In addition, the drug mobilizes extrasynaptic GLUN2B-containing NMDARs, which are coupled to cell death, to the synapses. Altered ratio of synaptic/extrasynaptic NMDARs decreases calcium responsiveness of neurons to neurotoxic soluble Aβ 1–42 and renders neurons resistant to early alteration of calcium homeostasis. The fast defensive response of FTY720 occurs through a Sphingosine-1-phosphate receptor (S1P-R) -dependent mechanism, as it is lost in the presence of S1P-R1 and S1P-R3 antagonists. We propose that rapid synaptic relocation of NMDARs might have direct impact on amelioration of cognitive performance in transgenic APPswe/PS1dE9 AD mice upon sub-chronic treatment with FTY720. PMID:28134307

  19. Acute Cocaine Induces Fast Activation of D1R and Progressive Deactivation of D2R Striatal Neurons: In vivo Optical MicroProbe [Ca2+]i Imaging

    PubMed Central

    Luo, Zhongchi; Volkow, Nora D.; Heintz, Nathaniel; Pan, Yingtian; Du, Congwu

    2011-01-01

    Cocaine induces fast dopamine increases in brain striatal regions, which are recognized to underlie its rewarding effects. Both dopamine D1 and D2 receptors are involved in cocaine’s reward but the dynamic downstream consequences of cocaine effects in striatum are not fully understood. Here we used transgenic mice expressing EGFP under the control of either the D1 receptor (D1R) or the D2 receptor (D2R) gene and microprobe optical imaging to assess the dynamic changes in intracellular calcium ([Ca2+]i) responses (used as marker of neuronal activation) to acute cocaine in vivo separately for D1R versus D2R expressing neurons in striatum. Acute cocaine (8 mg/kg ip) rapidly increased [Ca2+]i in D1R expressing neurons (10.6±3.2%) in striatum within 8.3±2.3min after cocaine administration after which the increases plateaued; these fast [Ca2+]i increases were blocked by pretreatment with a D1R antagonist (SCH 23390). In contrast cocaine induced progressive decreases in [Ca2+]i in D2R expressing neurons (10.4±5.8%) continuously throughout the 30min that followed cocaine administration; these slower [Ca2+]i decreases were blocked by pretreatment with a D2R antagonist (raclopride). Since activation of striatal D1R expressing neurons (direct-pathway) enhances cocaine reward whereas activation of D2R expressing neurons suppresses it (indirect-pathway) (Lobo et al., 2010), this suggests that cocaine’s rewarding effects entail both its fast stimulation of D1R (resulting in abrupt activation of direct-pathway neurons) and a slower stimulation of D2R (resulting in longer lasting deactivation of indirect-pathway neurons). We also provide direct in-vivo evidence of D2R and D1R interactions in the striatal responses to acute cocaine administration. PMID:21917801

  20. Intrinsic excitability changes induced by acute treatment of hippocampal CA1 pyramidal neurons with exogenous amyloid β peptide.

    PubMed

    Tamagnini, Francesco; Scullion, Sarah; Brown, Jon T; Randall, Andrew D

    2015-07-01

    Accumulation of beta-amyloid (Aβ) peptides in the human brain is a canonical pathological hallmark of Alzheimer's disease (AD). Recent work in Aβ-overexpressing transgenic mice indicates that increased brain Aβ levels can be associated with aberrant epileptiform activity. In line with this, such mice can also exhibit altered intrinsic excitability (IE) of cortical and hippocampal neurons: these observations may relate to the increased prevalence of seizures in AD patients. In this study, we examined what changes in IE are produced in hippocampal CA1 pyramidal cells after 2-5 h treatment with an oligomeric preparation of synthetic human Aβ 1-42 peptide. Whole cell current clamp recordings were compared between Aβ-(500 nM) and vehicle-(DMSO 0.05%) treated hippocampal slices obtained from mice. The soluble Aβ treatment did not produce alterations in sub-threshold intrinsic properties, including membrane potential, input resistance, and hyperpolarization activated "sag". Similarly, no changes were noted in the firing profile evoked by 500 ms square current supra-threshold stimuli. However, Aβ 500 nM treatment resulted in the hyperpolarization of the action potential (AP) threshold. In addition, treatment with Aβ at 500 nM depressed the after-hyperpolarization that followed both a single AP or 50 Hz trains of a number of APs between 5 and 25. These data suggest that acute exposure to soluble Aβ oligomers affects IE properties of CA1 pyramidal neurons differently from outcomes seen in transgenic models of amyloidopathy. However, in both chronic and acute models, the IE changes are toward hyperexcitability, reinforcing the idea that amyloidopathy and increased incidence in seizures might be causally related in AD patients.

  1. Comparison of the acute inhibitory effects of Tetrodotoxin (TTX) in rat and human neuronal networks for risk assessment purposes.

    PubMed

    Kasteel, Emma E J; Westerink, Remco H S

    2017-03-15

    Tetrodotoxin (TTX) is an extremely toxic marine neurotoxin. TTX inhibits voltage-gated sodium channels, resulting in a potentially lethal inhibition of neurotransmission. Despite numerous intoxications in Asia and Europe, limited (human) toxicological data are available for TTX. Additionally, the degree of interspecies differences for TTX is not well established, hampering the use of available (animal) data for human risk assessment and establishing regulatory limits for TTX concentrations in (shell)fish. We therefore used micro-electrode array (MEA) recordings as an integrated measure of neurotransmission to demonstrate that TTX inhibits neuronal electrical activity in both primary rat cortical cultures and human-induced pluripotent stem cell (hIPSC)-derived iCell(®) neurons in co-culture with hIPSC-derived iCell(®) astrocytes, with IC50 values of 7 and 10nM, respectively. From these data combined with LD50 values and IC50 concentrations of voltage-gated sodium channels derived from literature it can be concluded that interspecies differences are limited for TTX. Consequently, we used experimental animal data to derive a human acute reference dose of 1.33μg/kg body weight, which corresponds to maximum concentration of TTX in shellfish of 200μg/kg.

  2. Basic presynaptic functions in hippocampal neurons are not affected by acute or chronic lithium treatment.

    PubMed

    Lueke, Katharina; Kaiser, Tobias; Svetlitchny, Alexei; Welzel, Oliver; Wenzel, Eva M; Tyagarajan, Shiva; Kornhuber, Johannes; Groemer, Teja W

    2014-02-01

    Lithium is an effective mood-stabilizer in the treatment of bipolar affective disorder. While glycogen synthase kinase 3-mediated and inositol depletion-dependent effects of lithium have been described extensively in literature, there is very little knowledge about the consequences of lithium treatment on vesicle recycling and neurotransmitter availability. In the present study we have examined acute and chronic effects of lithium on synaptic vesicle recycling using primary hippocampal neurons. We found that exocytosis of readily releasable pool vesicles as well as recycling pool vesicles was unaffected by acute and chronic treatment within the therapeutic range or at higher lithium concentrations. Consistent with this observation, we also noticed that the network activity and number of active synapses within the network were also not significantly altered after lithium treatment. Taken together, as lithium treatment does not affect synaptic vesicle release at even high concentrations, our data suggest that therapeutic effects of lithium in bipolar affective disorder are not directly related to presynaptic function.

  3. Effects of extracellular delta-aminolaevulinic acid on sodium currents in acutely isolated rat hippocampal CA1 neurons.

    PubMed

    Wang, Lang; Yan, Dan; Gu, Yan; Sun, Li-Guang; Ruan, Di-Yun

    2005-12-01

    The effects of delta-aminolaevulinic acid (ALA) on voltage-gated sodium channel (VGSC) currents (I(Na)) in acutely isolated hippocampal CA1 neurons from 10- to 12-day-old Wistar rats were examined by using the whole-cell patch-clamp technique under voltage-clamp conditions. ALA from 0.01 microm to 20 microm was applied to the recorded neurons. Low concentrations of ALA (0.01-1.0 microM) increased I(Na) amplitude, whereas high concentrations of ALA (5.0-20.0 microM) decreased it. The average I(Na) amplitude reached a maximum of 117.4 +/- 3.9% (n = 9, P < 0.05) with 0.1 microM ALA, and decreased to 78.1 +/- 3.8% (n = 13, P < 0.05) with 10 microm ALA. ALA shifted the steady-state activation and inactivation curves of I(Na) in the hyperpolarizing direction with different V0.5, suggesting that ALA could depress the opening threshold of the voltage-gated sodium channel (VGSC) and thus increase the excitability of neurons through facilitating the opening of VGSC. The time course of recovery from inactivation was significantly prolonged at both low and high concentrations of ALA, whereas either low or high concentrations of ALA had no significant effect on the attenuation of I(Na) during stimulation at 5 Hz, indicating that the effect of ALA on VGSC is state-independent. Furthermore, we found that application of ascorbic acid, which blocks pro-oxidative effects in neurons, could prevent the increase of I(Na) amplitude at low concentrations of ALA. Baclofen, an agonist of GABAb receptors, induced some similar effects to ALA on VGSC, whereas bicuculline, an antagonist of GABAa receptors, could not prevent ALA-induced effects on VGSC. These results suggested that ALA regulated VGSC mainly through its pro-oxidative effects and GABAb receptor-mediated effects.

  4. Neuroprotective effect of acute melatonin treatment on hippocampal neurons against irradiation by inhibition of caspase-3

    PubMed Central

    LI, JIANGUO; ZHANG, GUOWEI; MENG, ZHUANGZHI; WANG, LINGZHAN; LIU, HAIYING; LIU, QIANG; BUREN, BATU

    2016-01-01

    Neuronal cell apoptosis is associated with various factors that induce neurological damage, including radiation exposure. When administered prior to exposure to radiation, a protective agent may prevent cellular and molecular injury. The present study aimed to investigate whether melatonin exerts a neuroprotective effect by inhibiting the caspase cell death pathway. Male Sprague-Dawley rats were administered melatonin (100 mg/kg body weight) 30 min prior to radiation exposure in red light during the evening. In order to elucidate whether melatonin has a neuroprotective role, immunohistochemistry, terminal deoxynucleotidyl transferase dUTP nick-end labeling, Nissl staining, reverse transcription-quantitative polymerase chain reaction, reactive oxygen species analysis and western blotting were performed. At 24 h post-melatonin treatment, caspase-3 mRNA and protein expression levels were significantly decreased. These results demonstrated that melatonin may protect hippocampal neurons via the inhibition of caspase-3 when exposed to irradiation. Therefore, caspase-3 inhibition serves a neuroprotective and antioxidant role in the interventional treatment of melatonin. The results of the present study suggested that melatonin may have a potential therapeutic effect against irradiation; however, further studies are required in order to elucidate the underlying antioxidant mechanisms. PMID:27313671

  5. Acute canine distemper encephalitis is associated with rapid neuronal loss and local immune activation.

    PubMed

    Rudd, Penny A; Bastien-Hamel, Louis-Etienne; von Messling, Veronika

    2010-04-01

    For most virus infections of the central nervous system (CNS), immune-mediated damage, the route of inoculation and death of infected cells all contribute to the pathology observed. To investigate the role of these factors in early canine distemper neuropathogenesis, we infected ferrets either intranasally or intraperitoneally with the neurovirulent canine distemper virus strain Snyder Hill. Regardless of the route of inoculation, the virus primarily targeted the olfactory bulb, brainstem, hippocampus and cerebellum, whereas only occasional foci were detected in the cortex. The infection led to widespread neuronal loss, which correlated with the clinical signs observed. Increased numbers of activated microglia, reactive gliosis and different pro-inflammatory cytokines were detected in the infected areas, suggesting that the presence and ultimate death of infected cells at early times after infection trigger strong local immune activation, despite the observed systemic immunosuppression.

  6. A microfluidic device to study neuronal and motor responses to acute chemical stimuli in zebrafish.

    PubMed

    Candelier, Raphaël; Murmu, Meena Sriti; Romano, Sebastián Alejo; Jouary, Adrien; Debrégeas, Georges; Sumbre, Germán

    2015-07-21

    Zebrafish larva is a unique model for whole-brain functional imaging and to study sensory-motor integration in the vertebrate brain. To take full advantage of this system, one needs to design sensory environments that can mimic the complex spatiotemporal stimulus patterns experienced by the animal in natural conditions. We report on a novel open-ended microfluidic device that delivers pulses of chemical stimuli to agarose-restrained larvae with near-millisecond switching rate and unprecedented spatial and concentration accuracy and reproducibility. In combination with two-photon calcium imaging and recordings of tail movements, we found that stimuli of opposite hedonic values induced different circuit activity patterns. Moreover, by precisely controlling the duration of the stimulus (50-500 ms), we found that the probability of generating a gustatory-induced behavior is encoded by the number of neurons activated. This device may open new ways to dissect the neural-circuit principles underlying chemosensory perception.

  7. Rebuilding a realistic corticostriatal “social network” from dissociated cells

    PubMed Central

    Garcia-Munoz, Marianela; Taillefer, Eddy; Pnini, Reuven; Vickers, Catherine; Miller, Jonathan; Arbuthnott, Gordon W.

    2015-01-01

    Many of the methods available for the study of cortical influences on striatal neurons have serious problems. In vivo the connectivity is so complex that the study of input from an individual cortical neuron to a single striatal cell is nearly impossible. Mixed corticostriatal cultures develop many connections from striatal cells to cortical cells, in striking contrast to the fact that only connections from cortical cells to striatal cells are present in vivo. Furthermore, interneuron populations are over-represented in organotypic cultures. For these reasons, we have developed a method for growing cortical and striatal neurons in separated compartments that allows cortical neurons to innervate striatal cells in culture. The method works equally well for acutely dissociated or cryopreserved neurons and allows a number of manipulations that are not otherwise possible. Either cortical or striatal compartments can be transfected with channel rhodopsins. The activity of both areas can be recorded in multielectrode arrays or individual patch recordings from pairs of cells. Finally, corticostriatal connections can be severed acutely. This procedure enables determination of the importance of corticostriatal interaction in the resting pattern of activity. These cultures also facilitate development of sensitive analytical network methods to track connectivity. PMID:25941477

  8. Prostaglandin E(2) inhibits calcium current in two sub-populations of acutely isolated mouse trigeminal sensory neurons.

    PubMed

    Borgland, Stephanie L; Connor, Mark; Ryan, Renae M; Ball, Helen J; Christie, MacDonald J

    2002-03-01

    Prostaglandins are important mediators of pain and inflammation. We have examined the effects of prostanoids on voltage-activated calcium currents (I(Ca)) in acutely isolated mouse trigeminal sensory neurons, using standard whole cell voltage clamp techniques. Trigeminal neurons were divided into two populations based on the presence (Type 2) or absence (Type 1) of low voltage-activated T-type I(Ca). The absence of T-type I(Ca) is highly correlated with sensitivity to mu-opioid agonists and the VR1 agonist capsaicin. In both populations of cells, high voltage-activated I(Ca) was inhibited by PGE(2) with an EC(50) of about 35 nM, to a maximum of 30 %. T-type I(Ca) was not inhibited by PGE(2). Pertussis toxin pre-treatment abolished the effects of PGE(2) in Type 2 cells, but not in Type 1 cells, whereas treatment with cholera toxin prevented the effects of PGE(2) in Type 1 cells, but not in Type 2 cells. Inhibition of I(Ca) by PGE(2) was associated with slowing of current activation and could be relieved with a large positive pre-pulse, consistent with inhibition of I(Ca) by G protein betagamma subunits. Reverse transcription-polymerase chain reaction of mRNA from trigeminal ganglia indicated that all four EP prostanoid receptors were present. However, in both Type 1 and Type 2 cells the effects of PGE(2) were only mimicked by the selective EP(3) receptor agonist ONO-AE-248, and not by selective agonists for EP(1) (ONO-DI-004), EP(2) (ONO-AE1-259) and EP(4) (ONO-AE1-329) receptors. These data indicate that two populations of neurons in trigeminal ganglia differing in their calcium channel expression, sensitivity to mu-opioids and capsaicin also have divergent mechanisms of PGE(2)-mediated inhibition of calcium channels, with Gi/Go type G proteins involved in one population, and Gs type G proteins in the other.

  9. Dissociative phenomenology of dissociative identity disorder.

    PubMed

    Dell, Paul F

    2002-01-01

    The goal of this study was to investigate the dissociative phenomenology of dissociative identity disorder (DID). The Multidimensional Inventory of Dissociation (MID) was administered to 34 patients with DID, 23 patients with dissociative disorder not otherwise specified (DDNOS), 52 patients with mixed psychiatric disorders, and 58 normal individuals. DID patients obtained significantly higher scores than the other three groups on 27 dissociation-related variables. DDNOS patients had significantly higher scores than normals and mixed psychiatric patients on 17 and 15 dissociation-related variables, respectively. The findings of the present study are virtually identical to a large body of replicated findings about the dissociative phenomenology of DID. This broad range of dissociation-related phenomena, which routinely occurs in individuals with DID, is largely absent from the DSM-IV-TR account of DID. Factor analysis of the 11 dimensions of dissociation that are measured by the MID extracted only one factor that accounted for 85% of the variance. It was concluded that dissociation is a unifactorial taxon or natural type that has different aspects or epiphenomena (i.e., amnesia, depersonalization, voices, trance, etc.).

  10. Acute reduction of neuronal RNA binding Elavl2 protein and Gap43 mRNA in mouse hippocampus after kainic acid treatment.

    PubMed

    Ohtsuka, Takafumi; Yano, Masato; Okano, Hideyuki

    2015-10-09

    Activity-dependent gene regulation in neurons has been hypothesized to be under transcriptional control and to include dramatic increases in immediate early genes (IEGs) after neuronal activity. In addition, several reports have focused on post-transcriptional regulation, which could be mediated by neuronal post-transcriptional regulators, including RNA binding proteins (RNABPs). One such protein family is the neuronal Elavls (nElavls; Elavl2, Elavl3, and Elavl4), whose members are widely expressed in peripheral and central nervous system. Previous reports showed that Elavl3 and 4 are up-regulated following repeated stimulation such as during cocaine administration, a seizure, or a spatial discrimination task. In this study, we focused on Elavl2, a candidate gene for schizophrenia and studied its role in neuronal activity. First we found that Elavl2 has a cell-type specific expression pattern that is highly expressed in hippocampal CA3 pyramidal neurons and hilar interneurons using Elavl2 specific antibody. Second, unexpectedly, we discovered that the Elavl2 protein level in the hippocampus was acutely down-regulated for 3 h after a kainic acid (KA)-induced seizure in the hippocampal CA3 region. In addition, level of Gap43 mRNA, a target mRNA of Elavl2 is decreased 12 h after KA treatment, thus suggesting the involvement of Elavl2 in activity-dependent RNA regulation.

  11. Serum neuron-specific enolase levels are upregulated in patients with acute lymphoblastic leukemia and are predictive of prognosis

    PubMed Central

    Wang, Liang; Geng, Qi-rong; Chen, Xiao-qin; Lu, Yue

    2016-01-01

    We explored the relationship between neuron-specific enolase (NSE) levels and the clinical features of acute lymphoblastic leukemia (ALL). Seventy ALL patients and forty-two healthy controls were enrolled in this study, and their serum NSE levels were measured using an electrochemiluminescence assay. The serum NSE concentration was higher in ALL patients than in healthy controls. In ALL patients, the mean serum NSE level declined after complete remission (CR) but increased with relapse. In addition, the mean serum NSE level was lower in the CR group than in the non-CR group. High NSE levels were associated with poorer progression-free and overall survival than low NSE levels. Serum NSE levels closely correlated with several clinical features, including the immunophenotype, risk stratification and serum lactate dehydrogenase levels. Multivariate analysis revealed that high NSE expression was an independent prognostic factor in adult ALL patients. NSE mRNA levels were also higher in ALL cell lines and bone marrow mononuclear cells from ALL patients than in control cells. These results suggested that NSE could be a clinical prognostic factor and a potential therapeutic target in ALL. PMID:27409171

  12. Alpers progressive infantile neuronal poliodystrophy: an acute neonatal form with findings of the fetal akinesia syndrome.

    PubMed

    Frydman, M; Jager-Roman, E; de Vries, L; Stoltenburg-Didinger, G; Nussinovitch, M; Sirota, L

    1993-08-01

    We report on 8 patients from two families with Alpers syndrome. The onset in one family was prenatal and in the 4 patients who were examined, severe microcephaly, intrauterine growth retardation, and typical manifestations of fetal akinesia, including retrognathia, joint limitations, and chest deformity were found. The second family presented with an early infantile form. All the affected offspring had micrognathia and one had findings of fetal akinesia, comparable to those seen in the other family. Microcephaly was mild at birth and progressed with age. Refractory neonatal convulsions, swallowing difficulties, and pneumonia complicated the clinical course of patients in both families, and all the patients died before age 20 months. Results of comprehensive biochemical and metabolic studies in both families were normal and the diagnosis was supported by demonstration of extensive progressive brain atrophy on CT and typical histological findings. Patients without a detectable defect in energy metabolism and normal liver histology comprise a distinct subset of Alpers syndrome. Until the metabolic defect(s) is defined, we suggest naming the acute neonatal form of this subset of Alpers syndrome "type 1."

  13. A novel high channel-count system for acute multisite neuronal recordings.

    PubMed

    Hofmann, Ulrich G; Folkers, Andre; Mösch, Florian; Malina, Thomas; Menne, Kerstin M L; Biella, Gerardo; Fagerstedt, Patriq; De Schutter, Erik; Jensen, Winnie; Yoshida, Ken; Hoehl, Dirk; Thomas, Uwe; Kindlundh, Maria G; Norlin, Peter; de Curtis, Marco

    2006-08-01

    Multisite recording represents a suitable condition to study microphysiology and network interactions in the central nervous system and, therefore, to understand brain functions. Several different materials and array configurations have been proposed for the development of new probes utilized to record brain activity from experimental animal models. We describe new multisite silicon probes that broaden the currently available application base for neuroscientists. The array arrangement of the probes recording sites was extended to increase their spatial resolution. Probes were integrated with a newly developed electronic hardware and novel software for advanced real-time processing and analysis. The new system, based on 32- and 64-electrode silicon probes, proved very valuable to record field potentials and single unit activity from the olfactory-limbic cortex of the in vitro isolated guinea-pig brain preparation and to acutely record unit activity at multiple sites from the cerebellar cortex in vivo. The potential advantages of the new system in comparison to the currently available technology are discussed.

  14. Changes in compressed neurons from dogs with acute and severe cauda equina constrictions following intrathecal injection of brain-derived neurotrophic factor-conjugated polymer nanoparticles☆

    PubMed Central

    Tan, Junming; Shi, Jiangang; Shi, Guodong; Liu, Yanling; Liu, Xiaohong; Wang, Chaoyang; Chen, Dechun; Xing, Shunming; Shen, Lianbing; Jia, Lianshun; Ye, Xiaojian; He, Hailong; Li, Jiashun

    2013-01-01

    This study established a dog model of acute multiple cauda equina constriction by experimental constriction injury (48 hours) of the lumbosacral central processes in dorsal root ganglia neurons. The repair effect of intrathecal injection of brain-derived neurotrophic factor with 15 mg encapsulated biodegradable poly(lactide-co-glycolide) nanoparticles on this injury was then analyzed. Dorsal root ganglion cells (L7) of all experimental dogs were analyzed using hematoxylin-eosin staining and immunohistochemistry at 1, 2 and 4 weeks following model induction. Intrathecal injection of brain-derived neurotrophic factor can relieve degeneration and inflammation, and elevate the expression of brain-derived neurotrophic factor in sensory neurons of compressed dorsal root ganglion. Simultaneously, intrathecal injection of brain-derived neurotrophic factor obviously improved neurological function in the dog model of acute multiple cauda equina constriction. Results verified that sustained intraspinal delivery of brain-derived neurotrophic factor encapsulated in biodegradable nanoparticles promoted the repair of histomorphology and function of neurons within the dorsal root ganglia in dogs with acute and severe cauda equina syndrome. PMID:25206593

  15. Time-Dependent Increases in Protease Activities for Neuronal Apoptosis in Spinal Cords of Lewis Rats During Development of Acute Experimental Autoimmune Encephalomyelitis

    PubMed Central

    Das, Arabinda; Guyton, M. Kelly; Matzelle, Denise D.; Ray, Swapan K.; Banik, Naren L.

    2008-01-01

    Multiple sclerosis (MS) is characterized by axonal demyelination and neurodegeneration, the latter having been inadequately explored in the MS animal model experimental autoimmune encephalomyelitis (EAE). The purpose of this study was to examine the time-dependent correlation between increased calpain and caspase activities and neurodegeneration in spinal cord tissues from Lewis rats with acute EAE. An increase in TUNEL-positive neurons and internucleosomal DNA fragmentation in EAE spinal cords suggested that neuronal death was a result of apoptosis on days 8–10 following induction of EAE. Increases in calpain expression in EAE correlated with activation of pro-apoptotic proteases, leading to apoptotic cell death beginning on day 8 of EAE, which occurred before the appearance of visible clinical symptoms. Increases in calcineurin expression and decreases in phospho-Bad (p-Bad) suggested Bad activation in apoptosis during acute EAE. Increases in the Bax:Bcl-2 ratio and activation of caspase-9 showed the involvement of mitochondria in apoptosis. Further, caspase-8 activation suggested induction of the death receptor–mediated pathway for apoptosis. Endoplasmic reticulum stress leading to caspase-3 activation was also observed, indicating that multiple apoptotic pathways were activated following EAE induction. In contrast, cell death was mostly a result of necrosis on the later day (day 11), when EAE entered a severe stage. From these findings, we conclude that increases in calpain and caspase activities play crucial roles in neuronal apoptosis during the development of acute EAE. PMID:18521931

  16. Chronic stress alters the dendritic morphology of callosal neurons and the acute glutamate stress response in the rat medial prefrontal cortex.

    PubMed

    Luczynski, Pauline; Moquin, Luc; Gratton, Alain

    2015-01-01

    We have previously reported that interhemispheric regulation of medial prefrontal cortex (PFC)-mediated stress responses is subserved by glutamate (GLU)- containing callosal neurons. Evidence of chronic stress-induced dendritic and spine atrophy among PFC pyramidal neurons led us to examine how chronic restraint stress (CRS) might alter the apical dendritic morphology of callosal neurons and the acute GLU stress responses in the left versus right PFC. Morphometric analyses of retrogradely labeled, dye-filled PFC callosal neurons revealed hemisphere-specific CRS-induced dendritic retraction; whereas significant dendritic atrophy occurred primarily within the distal arbor of left PFC neurons, it was observed within both the proximal and distal arbor of right PFC neurons. Overall, CRS also significantly reduced spine densities in both hemispheres with the greatest loss occurring among left PFC neurons, mostly at the distal extent of the arbor. While much of the overall decrease in dendritic spine density was accounted by the loss of thin spines, the density of mushroom-shaped spines, despite being fewer in number, was halved. Using microdialysis we found that, compared to controls, basal PFC GLU levels were significantly reduced in both hemispheres of CRS animals and that their GLU response to 30 min of tail-pinch stress was significantly prolonged in the left, but not the right PFC. Together, these findings show that a history of chronic stress alters the dendritic morphology and spine density of PFC callosal neurons and suggest a mechanism by which this might disrupt the interhemispheric regulation of PFC-mediated responses to subsequent stressors.

  17. Acute estradiol protects CA1 neurons from ischemia-induced apoptotic cell death via the PI3K/Akt pathway

    PubMed Central

    Jover-Mengual, Teresa; Miyawaki, Takahiro; Latuszek, Adrianna; Alborch, Enrique; Zukin, R. Suzanne; Etgen, Anne M.

    2010-01-01

    Global ischemia arising during cardiac arrest or cardiac surgery causes highly selective, delayed death of hippocampal CA1 neurons. Exogenous estradiol ameliorates global ischemia-induced neuronal death and cognitive impairment in male and female rodents. However, the molecular mechanisms by which a single acute injection of estradiol administered after the ischemic event intervenes in global ischemia-induced apoptotic cell death are unclear. Here we show that acute estradiol acts via the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling cascade to protect CA1 neurons in ovariectomized female rats. We demonstrate that global ischemia promotes early activation of glycogen synthase kinase-3β (GSK3β) and forkhead transcription factor of the O class (FOXO)3A, known Akt targets that are related to cell survival, and activation of caspase-3. Estradiol prevents ischemia-induced dephosphorylation and activation of GSK3β and FOXO3A, and the caspase death cascade. These findings support a model whereby estradiol acts by activation of PI3K/Akt signaling to promote neuronal survival in the face of global ischemia. PMID:20114038

  18. Dissociating motor cortex from the motor

    PubMed Central

    Schieber, Marc H

    2011-01-01

    Abstract During closed-loop control of a brain–computer interface, neurons in the primary motor cortex can be intensely active even though the subject may be making no detectable movement or muscle contraction. How can neural activity in the primary motor cortex become dissociated from the movements and muscles of the native limb that it normally controls? Here we examine circumstances in which motor cortex activity is known to dissociate from movement – including mental imagery, visuo-motor dissociation and instructed delay. Many such motor cortex neurons may be related to muscle activity only indirectly. Furthermore, the integration of thousands of synaptic inputs by individual α-motoneurons means that under certain circumstances even cortico-motoneuronal cells, which make monosynaptic connections to α-motoneurons, can become dissociated from muscle activity. The natural ability of motor cortex neurons under voluntarily control to become dissociated from bodily movement may underlie the utility of this cortical area for controlling brain–computer interfaces. PMID:22005673

  19. The new P2Y-like receptor G protein-coupled receptor 17 mediates acute neuronal injury and late microgliosis after focal cerebral ischemia in rats.

    PubMed

    Zhao, B; Zhao, C Z; Zhang, X Y; Huang, X Q; Shi, W Z; Fang, S H; Lu, Y B; Zhang, W P; Xia, Q; Wei, E Q

    2012-01-27

    G protein-coupled receptor 17 (GPR17), the new P2Y-like receptor, is phylogenetically related to the P2Y and cysteinyl leukotriene receptors, and responds to both uracil nucleotides and cysteinyl leukotrienes. GPR17 has been proposed to be a damage sensor in ischemic stroke; however, its role in brain inflammation needs further detailed investigation. Here, we extended previous studies on the spatiotemporal profiles of GPR17 expression and localization, and their implications for brain injury after focal cerebral ischemia. We found that in the ischemic core, GPR17 mRNA and protein levels were upregulated at both 12-24 h and 7-14 days, but in the boundary zone the levels increased 7-14 days after reperfusion. The spatiotemporal pattern of GPR17 expression well matched the acute and late (subacute/chronic) responses in the ischemic brain. According to previous findings, in the acute phase, after ischemia (24 h), upregulated GPR17 was localized in injured neurons in the ischemic core and in a few microglia in the ischemic core and boundary zone. In the late phase (14 days), it was localized in microglia, especially in activated (ED1-positive) microglia in the ischemic core, but weakly in most microglia in the boundary zone. No GPR17 was detectable in astrocytes. GPR17 knockdown by a small interfering RNA attenuated the neurological dysfunction, infarction, and neuron loss at 24 h, and brain atrophy, neuron loss, and microglial activation at 14 days after reperfusion. Thus, GPR17 might mediate acute neuronal injury and late microgliosis after focal cerebral ischemia.

  20. The stressed female brain: neuronal activity in the prelimbic but not infralimbic region of the medial prefrontal cortex suppresses learning after acute stress.

    PubMed

    Maeng, Lisa Y; Shors, Tracey J

    2013-01-01

    Women are nearly twice as likely as men to suffer from anxiety and post-traumatic stress disorder (PTSD), indicating that many females are especially vulnerable to stressful life experience. A profound sex difference in the response to stress is also observed in laboratory animals. Acute exposure to an uncontrollable stressful event disrupts associative learning during classical eyeblink conditioning in female rats but enhances this same type of learning process in males. These sex differences in response to stress are dependent on neuronal activity in similar but also different brain regions. Neuronal activity in the basolateral nucleus of the amygdala (BLA) is necessary in both males and females. However, neuronal activity in the medial prefrontal cortex (mPFC) during the stressor is necessary to modify learning in females but not in males. The mPFC is often divided into its prelimbic (PL) and infralimbic (IL) subregions, which differ both in structure and function. Through its connections to the BLA, we hypothesized that neuronal activity within the PL, but not IL, during the stressor is necessary to suppress learning in females. To test this hypothesis, either the PL or IL of adult female rats was bilaterally inactivated with GABAA agonist muscimol during acute inescapable swim stress. About 24 h later, all subjects were trained with classical eyeblink conditioning. Though stressed, females without neuronal activity in the PL learned well. In contrast, females with IL inactivation during the stressor did not learn well, behaving similarly to stressed vehicle-treated females. These data suggest that exposure to a stressful event critically engages the PL, but not IL, to disrupt associative learning in females. Together with previous studies, these data indicate that the PL communicates with the BLA to suppress learning after a stressful experience in females. This circuit may be similarly engaged in women who become cognitively impaired after stressful life

  1. Recovery of hypothalamic tuberoinfundibular dopamine neurons from acute toxicant exposure is dependent upon protein synthesis and associated with an increase in parkin and ubiquitin carboxy-terminal hydrolase-L1 expression.

    PubMed

    Benskey, Matthew; Behrouz, Bahareh; Sunryd, Johan; Pappas, Samuel S; Baek, Seung-Hoon; Huebner, Marianne; Lookingland, Keith J; Goudreau, John L

    2012-06-01

    Hypothalamic tuberoinfundibular dopamine (TIDA) neurons remain unaffected in Parkinson disease (PD) while there is significant degeneration of midbrain nigrostriatal dopamine (NSDA) neurons. A similar pattern of susceptibility is observed in acute and chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse and rotenone rat models of degeneration. It is not known if the resistance of TIDA neurons is a constitutive or induced cell-autonomous phenotype for this unique subset of DA neurons. In the present study, treatment with a single injection of MPTP (20 mg/kg; s.c.) was employed to examine the response of TIDA versus NSDA neurons to acute injury. An acute single dose of MPTP caused an initial loss of DA from axon terminals of both TIDA and NSDA neurons, with recovery occurring solely in TIDA neurons by 16 h post-treatment. Initial loss of DA from axon terminals was dependent on a functional dopamine transporter (DAT) in NSDA neurons but DAT-independent in TIDA neurons. The active metabolite of MPTP, 1-methyl, 4-phenylpyradinium (MPP+), reached higher concentration and was eliminated slower in TIDA compared to NSDA neurons, which indicates that impaired toxicant bioactivation or distribution is an unlikely explanation for the observed resistance of TIDA neurons to MPTP exposure. Inhibition of protein synthesis prevented TIDA neuron recovery, suggesting that the ability to recover from injury was dependent on an induced, rather than a constitutive cellular mechanism. Further, there were no changes in total tyrosine hydroxylase (TH) expression following MPTP, indicating that up-regulation of the rate-limiting enzyme in DA synthesis does not account for TIDA neuronal recovery. Differential candidate gene expression analysis revealed a time-dependent increase in parkin and ubiquitin carboxyl-terminal hydrolase-L1 (UCH-L1) expression (mRNA and protein) in TIDA neurons during recovery from injury. Parkin expression was also found to increase with incremental

  2. Volatile Organic Compound Gamma-Butyrolactone Released upon Herpes Simplex Virus Type -1 Acute Infection Modulated Membrane Potential and Repressed Viral Infection in Human Neuron-Like Cells

    PubMed Central

    Waguespack, Yan; Figliozzi, Robert W.; Kharel, Madan K.; Zhang, Qiaojuan; Martin-Caraballo, Miguel

    2016-01-01

    Herpes Simplex Virus Type -1 (HSV-1) infections can cause serious complications such as keratitis and encephalitis. The goal of this study was to identify any changes in the concentrations of volatile organic compounds (VOCs) produced during HSV-1 infection of epithelial cells that could potentially be used as an indicator of a response to stress. An additional objective was to study if any VOCs released from acute epithelial infection may influence subsequent neuronal infection to facilitate latency. To investigate these hypotheses, Vero cells were infected with HSV-1 and the emission of VOCs was analyzed using two-dimensional gas chromatograph/mass spectrometry (2D GC/MS). It was observed that the concentrations of gamma-butyrolactone (GBL) in particular changed significantly after a 24-hour infection. Since HSV-1 may establish latency in neurons after the acute infection, GBL was tested to determine if it exerts neuronal regulation of infection. The results indicated that GBL altered the resting membrane potential of differentiated LNCaP cells and promoted a non-permissive state of HSV-1 infection by repressing viral replication. These observations may provide useful clues towards understanding the complex signaling pathways that occur during the HSV-1 primary infection and establishment of viral latency. PMID:27537375

  3. Acute morphine induces matrix metalloproteinase-9 up-regulation in primary sensory neurons to mask opioid-induced analgesia in mice

    PubMed Central

    2012-01-01

    Background Despite decades of intense research efforts, actions of acute opioids are not fully understood. Increasing evidence suggests that in addition to well-documented antinociceptive effects opioids also produce paradoxical hyperalgesic and excitatory effects on neurons. However, most studies focus on the pronociceptive actions of chronic opioid exposure. Matrix metalloproteinase 9 (MMP-9) plays an important role in neuroinflammation and neuropathic pain development. We examined MMP-9 expression and localization in dorsal root ganglia (DRGs) after acute morphine treatment and, furthermore, the role of MMP-9 in modulating acute morphine-induced analgesia and hyperalgesia in mice. Results Subcutaneous morphine induced a marked up-regulation of MMP-9 protein in DRGs but not spinal cords. Morphine also increased MMP-9 activity and mRNA expression in DRGs. MMP-9 up-regulation peaked at 2 h but returned to the baseline after 24 h. In DRG tissue sections, MMP-9 is expressed in small and medium-sized neurons that co-express mu opioid receptors (MOR). In DRG cultures, MOR agonists morphine, DAMGO, and remifentanil each increased MMP-9 expression in neurons, whereas the opioid receptor antagonist naloxone and the MOR-selective antagonist D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2 (CTAP) suppressed morphine-induced MMP-9 expression. Notably, subcutaneous morphine-induced analgesia was enhanced and prolonged in Mmp9 knockout mice and also potentiated in wild-type mice receiving intrathecal injection of MMP-9 inhibitors. Consistently, intrathecal injection of specific siRNA targeting MMP-9 reduced MMP-9 expression in DRGs and enhanced and prolonged morphine analgesia. Subcutaneous morphine also produced heat hyperalgesia at 24 h, but this opioid-induced hyperalgesia was not enhanced after MMP-9 deletion or inhibition. Conclusions Transient MMP-9 up-regulation in DRG neurons can mask opioid analgesia, without modulating opioid-induced hyperalgesia. Distinct molecular

  4. Rho kinase inhibition following traumatic brain injury in mice promotes functional improvement and acute neuron survival but has little effect on neurogenesis, glial responses or neuroinflammation.

    PubMed

    Bye, Nicole; Christie, Kimberly J; Turbic, Alisa; Basrai, Harleen S; Turnley, Ann M

    2016-05-01

    Inhibition of the Rho/Rho kinase pathway has been shown to be beneficial in a variety of neural injuries and diseases. In this manuscript we investigate the role of Rho kinase inhibition in recovery from traumatic brain injury using a controlled cortical impact model in mice. Mice subjected to a moderately severe TBI were treated for 1 or 4 weeks with the Rho kinase inhibitor Y27632, and functional outcomes and neuronal and glial cell responses were analysed at 1, 7 and 35 days post-injury. We hypothesised that Y27632-treated mice would show functional improvement, with augmented recruitment of neuroblasts from the SVZ and enhanced survival of newborn neurons in the pericontusional cortex, with protection against neuronal degeneration, neuroinflammation and modulation of astrocyte reactivity and blood-brain-barrier permeability. While Rho kinase inhibition enhanced recovery of motor function after trauma, there were no substantial increases in the recruitment of DCX(+) neuroblasts or the number of BrdU(+) or EdU(+) labelled newborn neurons in the pericontusional cortex of Y27632-treated mice. Inhibition of Rho kinase significantly reduced the number of degenerating cortical neurons at 1day post-injury compared to saline controls but had no longer term effect on neuronal degeneration, with only modest effects on astrocytic reactivity and macrophage/microglial responses. Overall, this study showed that Rho kinase contributes to acute neurodegenerative processes in the injured cortex but does not play a significant role in SVZ neural precursor cell-derived adult neurogenesis, glial responses or blood-brain barrier permeability following a moderately severe brain injury.

  5. Optical electrocorticogram (OECoG) using wide-field calcium imaging reveals the divergence of neuronal and glial activity during acute rodent seizures.

    PubMed

    Daniel, Andy G S; Laffont, Philippe; Zhao, Mingrui; Ma, Hongtao; Schwartz, Theodore H

    2015-08-01

    The role of glia in epilepsy has been widely debated. Using in vivo bulk loading of calcium dyes, we imaged neuronal and glial activity in an acute pharmacologic rodent model of neocortical seizures. Optical calcium-based ECoG maps revealed that neuronal waves propagated rapidly and remained mostly confined to the seizure focus. Glial waves were triggered by ictal onset but propagated slowly in a stereotypical fashion far beyond the seizure focus. Although related at their onset, the divergence of these two phenomena during seizure evolution calls into question their interdependence and the criticality of the role of glia in seizure onset and neurovascular coupling. This article is part of a Special Issue entitled "Status Epilepticus".

  6. Guilt by dissociation: guilt primes augment the relationship between dissociative tendencies and state dissociation.

    PubMed

    Rugens, Alex; Terhune, Devin Blair

    2013-03-30

    We examined the influence of guilt on the relationship between dissociative tendencies and state dissociation during mirror-gazing in a non-clinical sample. Dissociative tendencies correlated with state dissociation following guilt primes, but not after negative or neutral primes. This suggests that guilt augments the relationship between dissociative tendencies and state dissociation.

  7. Attenuation of acute and chronic effects of morphine by the imidazoline receptor ligand 2-(2-benzofuranyl)-2-imidazoline in rat locus coeruleus neurons

    PubMed Central

    Ruiz-Durántez, Eduardo; Torrecilla, María; Pineda, Joseba; Ugedo, Luisa

    2003-01-01

    The aim of this study was to determine if 2-(2-benzofuranyl)-2-imidazoline (2-BFI) interacts with the opioid system in the rat locus coeruleus, using single-unit extracellular recordings. In morphine-dependent rats, acute administration of the selective imidazoline receptor ligands 2-BFI (10 and 40 mg kg−1, i.p. and 100 μg, i.c.v.) or valldemossine (10 mg kg−1, i.p.) did not modify the naloxone-induced hyperactivity of locus coeruleus neurons compared with that observed in the morphine-dependent control group. After chronic administration of 2-BFI (10 mg kg−1, i.p., three times daily, for 5 days) and morphine, naloxone-induced hyperactivity and tolerance to morphine were attenuated. This effect was not observed when a lower dose of 2-BFI (1 mg kg−1, i.p.) or valldemossine (10 mg kg−1, i.p.) were used. Acute administration of 2-BFI (10 and 40 mg kg−1, i.p. and 100 μg, i.c.v.) but not valldemossine (40 mg kg−1, i.p.) diminished the potency of morphine to inhibit locus coeruleus neuron activity in vivo (ED50 values increased by 2.3, 2.9; and 3.1 fold respectively). Similarly, the potency of Met5-enkephalin to inhibit locus coeruleus neurons was decreased when 2-BFI (100 μM) was applied to rat brain slices (EC50 increased by 5.6; P<0.05). The present data demonstrate that there is an interaction between 2-BFI and the opioid system in the locus coeruleus. This interaction leads to an attenuation of both the hyperactivity of locus coeruleus neurons during opiate withdrawal and the development of tolerance to morphine when 2-BFI is chronically administered. These results suggest that imidazoline drugs may prove to be useful agents for the management of opioid dependence and tolerance. PMID:12569074

  8. Acute p38-mediated inhibition of NMDA-induced outward currents in hippocampal CA1 neurons by interleukin-1beta.

    PubMed

    Zhang, Ruoyu; Sun, Li; Hayashi, Yoshinori; Liu, Xia; Koyama, Susumu; Wu, Zhou; Nakanishi, Hiroshi

    2010-04-01

    Interleukin-1beta (IL-1beta) is a potent pro-inflammatory cytokine that is primarily produced by microglia in the brain. IL-1beta inhibits N-methyl-d-aspartate (NMDA)-induced outward currents (I(NMDA-OUT)) through IL-1 type I receptor (IL-1RI) in hippocampal CA1 neurons (Zhang, R., Yamada, J., Hayashi, Y., Wu, Z, Koyama, S., Nakanishi, H., 2008. Inhibition of NMDA-induced outward currents by interleukin-1beta in hippocampal neurons, Biochem. Biophys. Res. Commun. 372, 816-820). Although IL-1RI is associated with mitogen-activated protein kinases, their involvement in the effect of IL-1beta on I(NMDA-OUT) remains unclear. In the present study, we demonstrate that IL-1beta caused activation of p38 mitogen-activated protein kinase and that the p38 inhibitor SB203580 significantly blocked the effect of IL-1beta on I(NMDA-OUT) in hippocampal CA1 neurons. Furthermore, the intracellular perfusion of active recombinant p38alpha significantly decreased the mean amplitude of I(NMDA-OUT). In neurons prepared from inflamed hippocampus, the mean amplitude of I(NMDA-OUT) was significantly reduced. In the inflamed hippocampus, IL-1beta and IL-1RI were expressed mainly in microglia and neurons, respectively. These results suggest that IL-1beta increases the excitability of hippocampal CA1 neurons in the p38-dependent inhibition of I(NMDA-OUT).

  9. Radiogenic changes in the behavior and physiology of the spontaneously hypertensive rat: evidence for a dissociation between acute hypotension and incapacitation

    SciTech Connect

    Mickley, G.A.; Teitelbaum, H.; Parker, G.A.; Vieras, F.; Dennison, B.A.; Bonney, C.H.

    1982-07-01

    Immediately following exposure to a sufficiently large dose of ionizing radiation, rats and several other species experience a transient period of acute hypotension and an accompanying deficit in performance. Although significant correlations have been reported between the drop in blood pressure and the early transient incapacitation (ETI) and a causal relationship has been suggested, the extent to which hypotension precipitates the occurrence of the behavioral deficits remains uncertain. The present experiments investigated both radiogenic blood pressure and performance changes in a strain of rat bred for hypertension (spontaneously hypertensive rat: SHR) in order to determine if high blood pressure might attenuate ETI. Although male SHRs experienced a severe ETI and a drop in blood pressure, much of the data is inconsistent with the hypothesis that hypotension causes performance decrements. In an additional series of studies, blood volume and serum chemistry data were analyzed. Male SHRs were significantly higher than normotensive controls on several blood chemistry determinations. Exposure to ionizing radiation, more often than not, enhanced these differences. These results could not be explained on the basis of radiogenic blood volume fluctuations.

  10. The Many Faces of Dissociation: Opportunities for Innovative Research in Psychiatry

    PubMed Central

    2014-01-01

    It has been claimed that the progress of psychiatry has lagged behind that of other medical disciplines over the last few decades. This may suggest the need for innovative thinking and research in psychiatry, which should consider neglected areas as topics of interest in light of the potential progress which might be made in this regard. This review is concerned with one such field of psychiatry: dissociation and dissociative disorders. Dissociation is the ultimate form of human response to chronic developmental stress, because patients with dissociative disorders report the highest frequency of childhood abuse and/or neglect among all psychiatric disorders. The cardinal feature of dissociation is a disruption in one or more mental functions. Dissociative amnesia, depersonalization, derealization, identity confusion, and identity alterations are core phenomena of dissociative psychopathology which constitute a single dimension characterized by a spectrum of severity. While dissociative identity disorder (DID) is the most pervasive condition of all dissociative disorders, partial representations of this spectrum may be diagnosed as dissociative amnesia (with or without fugue), depersonalization disorder, and other specified dissociative disorders such as subthreshold DID, dissociative trance disorder, acute dissociative disorders, and identity disturbances due to exposure to oppression. In addition to constituting disorders in their own right, dissociation may accompany almost every psychiatric disorder and operate as a confounding factor in general psychiatry, including neurobiological and psycho-pharmacological research. While an anti- dissociative drug does not yet exist, appropriate psychotherapy leads to considerable improvement for many patients with dissociative disorders. PMID:25598819

  11. Neuronal polarization in the developing cerebral cortex

    PubMed Central

    Sakakibara, Akira; Hatanaka, Yumiko

    2015-01-01

    Cortical neurons consist of excitatory projection neurons and inhibitory GABAergic interneurons, whose connections construct highly organized neuronal circuits that control higher order information processing. Recent progress in live imaging has allowed us to examine how these neurons differentiate during development in vivo or in in vivo-like conditions. These analyses have revealed how the initial steps of polarization, in which neurons establish an axon, occur. Interestingly, both excitatory and inhibitory cortical neurons establish neuronal polarity de novo by undergoing a multipolar stage reminiscent of the manner in which polarity formation occurs in hippocampal neurons in dissociated culture. In this review, we focus on polarity formation in cortical neurons and describe their typical morphology and dynamic behavior during the polarization period. We also discuss cellular and molecular mechanisms underlying polarization, with reference to polarity formation in dissociated hippocampal neurons in vitro. PMID:25904841

  12. Narrative, dialogue, and dissociation.

    PubMed

    Gedo, Paul M

    2014-02-01

    This paper explores dissociative phenomena as disruptions of dialogue between persons, and disruptions of internal narratives. A dissociating patient temporarily loses ability to convey his or her inner experience to the therapist. The disconnection between dialogue and internal experience can mislead both participants, or distract them from underlying connotations. Dissociation also disrupts the patient's sense of internal coherence and internal conversation. Dissociation represents a regression to an early, preverbal mode of (internal and external) communication. The challenge for the dyad is to restore dialogue and then to discern the multiply determined meanings of the dissociative communication. This therapeutic work allows the patient to achieve a more coherent sense of self and of his or her life course.

  13. Neurokinin B Causes Acute GnRH Secretion and Repression of GnRH Transcription in GT1–7 GnRH Neurons

    PubMed Central

    Glidewell-Kenney, Christine A.; Shao, Paul P.; Iyer, Anita K.; Grove, Anna M. H.; Meadows, Jason D.

    2013-01-01

    Genetic studies in human patients with idiopathic hypogonadotropic hypogonadism (IHH) identified mutations in the genes that encode neurokinin B (NKB) and the neurokinin 3 receptor (NK3R). However, determining the mechanism whereby NKB regulates gonadotropin secretion has been difficult because of conflicting results from in vivo studies investigating the luteinizing hormone (LH) response to senktide, a NK3R agonist. NK3R is expressed in a subset of GnRH neurons and in kisspeptin neurons that are known to regulate GnRH secretion. Thus, one potential source of inconsistency is that NKB could produce opposing direct and indirect effects on GnRH secretion. Here, we employ the GT1-7 cell model to elucidate the direct effects of NKB on GnRH neuron function. We find that GT1-7 cells express NK3R and respond to acute senktide treatment with c-Fos induction and increased GnRH secretion. In contrast, long-term senktide treatment decreased GnRH secretion. Next, we focus on the examination of the mechanism underlying the long-term decrease in secretion and determine that senktide treatment represses transcription of GnRH. We further show that this repression of GnRH transcription may involve enhanced c-Fos protein binding at novel activator protein-1 (AP-1) half-sites identified in enhancer 1 and the promoter, as well as chromatin remodeling at the promoter of the GnRH gene. These data indicate that NKB could directly regulate secretion from NK3R-expressing GnRH neurons. Furthermore, whether the response is inhibitory or stimulatory toward GnRH secretion could depend on the history or length of exposure to NKB because of a repressive effect on GnRH transcription. PMID:23393128

  14. Dissociative recombination in aeronomy

    NASA Technical Reports Server (NTRS)

    Fox, J. L.

    1989-01-01

    The importance of dissociative recombination in planetary aeronomy is summarized, and two examples are discussed. The first is the role of dissociative recombination of N2(+) in the escape of nitrogen from Mars. A previous model is updated to reflect new experimental data on the electronic states of N produced in this process. Second, the intensity of the atomic oxygen green line on the nightside of Venus is modeled. Use is made of theoretical rate coefficients for production of O (1S) in dissociative recombination from different vibrational levels of O2(+).

  15. Dissociative Identity Disorder

    PubMed Central

    2009-01-01

    A brief description of the controversies surrounding the diagnosis of dissociative identity disorder is presented, followed by a discussion of the proposed similarities and differences between dissociative identity disorder and borderline personality disorder. The phenomenon of autohypnosis in the context of early childhood sexual trauma and disordered attachment is discussed, as is the meaning of alters or alternate personalities. The author describes recent neurosciences research that may relate the symptoms of dissociative identity disorder to demonstrable disordered attention and memory processes. A clinical description of a typical patient presentation is included, plus some recommendations for approaches to treatment. PMID:19724751

  16. Patch-clamp recordings of rat neurons from acute brain slices of the somatosensory cortex during magnetic stimulation

    PubMed Central

    Pashut, Tamar; Magidov, Dafna; Ben-Porat, Hana; Wolfus, Shuki; Friedman, Alex; Perel, Eli; Lavidor, Michal; Bar-Gad, Izhar; Yeshurun, Yosef; Korngreen, Alon

    2014-01-01

    Although transcranial magnetic stimulation (TMS) is a popular tool for both basic research and clinical applications, its actions on nerve cells are only partially understood. We have previously predicted, using compartmental modeling, that magnetic stimulation of central nervous system neurons depolarized the soma followed by initiation of an action potential in the initial segment of the axon. The simulations also predict that neurons with low current threshold are more susceptible to magnetic stimulation. Here we tested these theoretical predictions by combining in vitro patch-clamp recordings from rat brain slices with magnetic stimulation and compartmental modeling. In agreement with the modeling, our recordings demonstrate the dependence of magnetic stimulation-triggered action potentials on the type and state of the neuron and its orientation within the magnetic field. Our results suggest that the observed effects of TMS are deeply rooted in the biophysical properties of single neurons in the central nervous system and provide a framework both for interpreting existing TMS data and developing new simulation-based tools and therapies. PMID:24917788

  17. Importance of Being Nernst: Synaptic Activity and Functional Relevance in Stem Cell-derived Neurons

    DTIC Science & Technology

    2015-07-26

    dissociated primary neurons, immortalized cell lines derived from neuronal and non-neuronal tissues and, most recently, stem cells. The predictive value of...repair of damaged neural tissues [8,9]. However, SCN models must be shown to be competent to form context-appropriate, functioning neurons before...of neuronal maturation have been well-described in dissociated cultures of primary neurons, it is important to recognize that the source tissues

  18. Characterization of Ca(2+) channels in rat subthalamic nucleus neurons.

    PubMed

    Song, W J; Baba, Y; Otsuka, T; Murakami, F

    2000-11-01

    The subthalamic nucleus (STN) plays a key role in motor control. Although previous studies have suggested that Ca(2+) conductances may be involved in regulating the activity of STN neurons, Ca(2+) channels in this region have not yet been characterized. We have therefore investigated the subtypes and functional characteristics of Ca(2+) conductances in STN neurons, in both acutely isolated and slice preparations. Acutely isolated STN cells were identified by retrograde filling with the fluorescent dye, Fluoro-Gold. In acutely isolated STN neurons, Cd(2+)-sensitive, depolarization-activated Ba(2+) currents were observed in all cells studied. The current-voltage relationship and current kinetics were characteristic of high-voltage-activated Ca(2+) channels. The steady-state voltage-dependent activation curves and inactivation curves could both be fitted with a single Boltzmann function. Currents evoked with a prolonged pulse, however, inactivated with multiple time constants, suggesting either the presence of more than one Ca(2+) channel subtype or multiple inactivation processes with a single channel type in STN neurons. Experiments using organic Ca(2+) channel blockers revealed that on average, 21% of the current was nifedipine sensitive, 52% was sensitive to omega-conotoxin GVIA, 16% was blocked by a high concentration of omega-agatoxin IVA (200 nM), and the remainder of the current (9%) was resistant to the co-application of all blockers. These currents had similar voltage dependencies, but the nifedipine-sensitive current and the resistant current activated at slightly lower voltages. omega-Agatoxin IVA at 20 nM was ineffective in blocking the current. Together, the above results suggest that acutely isolated STN neurons have all subtypes of high-voltage-activated Ca(2+) channels except for P-type, but have no low-voltage-activated channels. Although acutely isolated neurons provide a good preparation for whole cell voltage-clamp study, dendritic processes are

  19. Dopamine Modulates Spike Timing-Dependent Plasticity and Action Potential Properties in CA1 Pyramidal Neurons of Acute Rat Hippocampal Slices

    PubMed Central

    Edelmann, Elke; Lessmann, Volkmar

    2011-01-01

    Spike timing-dependent plasticity (STDP) is a cellular model of Hebbian synaptic plasticity which is believed to underlie memory formation. In an attempt to establish a STDP paradigm in CA1 of acute hippocampal slices from juvenile rats (P15–20), we found that changes in excitability resulting from different slice preparation protocols correlate with the success of STDP induction. Slice preparation with sucrose containing ACSF prolonged rise time, reduced frequency adaptation, and decreased latency of action potentials in CA1 pyramidal neurons compared to preparation in conventional ASCF, while other basal electrophysiological parameters remained unaffected. Whereas we observed prominent timing-dependent long-term potentiation (t-LTP) to 171 ± 10% of controls in conventional ACSF, STDP was absent in sucrose prepared slices. This sucrose-induced STDP deficit could not be rescued by stronger STDP paradigms, applying either more pre- and/or postsynaptic stimuli, or by a higher stimulation frequency. Importantly, slice preparation with sucrose containing ACSF did not eliminate theta-burst stimulation induced LTP in CA1 in field potential recordings in our rat hippocampal slices. Application of dopamine (for 10–20 min) to sucrose prepared slices completely rescued t-LTP and recovered action potential properties back to levels observed in ACSF prepared slices. Conversely, acute inhibition of D1 receptor signaling impaired t-LTP in ACSF prepared slices. No similar restoring effect for STDP as seen with dopamine was observed in response to the β-adrenergic agonist isoproterenol. ELISA measurements demonstrated a significant reduction of endogenous dopamine levels (to 61.9 ± 6.9% of ACSF values) in sucrose prepared slices. These results suggest that dopamine signaling is involved in regulating the efficiency to elicit STDP in CA1 pyramidal neurons. PMID:22065958

  20. Electroacupuncture Reduces the Effects of Acute Noxious Stimulation on the Electrical Activity of Pain-Related Neurons in the Hippocampus of Control and Neuropathic Pain Rats

    PubMed Central

    Wang, Jun-Ying; Chen, Renbo; Feng, Xiu-Mei; Yan, Yaxia; Lippe, Irmgard Th.

    2016-01-01

    To study the effects of acupuncture analgesia on the hippocampus, we observed the effects of electroacupuncture (EA) and mitogen-activated protein kinase (MEK) inhibitor on pain-excited neurons (PENs) and pain-inhibited neurons (PINs) in the hippocampal area CA1 of sham or chronic constrictive injury (CCI) rats. The animals were randomly divided into a control, a CCI, and a U0126 (MEK1/2 inhibitor) group. In all experiments, we briefly (10-second duration) stimulated the sciatic nerve electrically and recorded the firing rates of PENs and PINs. The results showed that in both sham and CCI rats brief sciatic nerve stimulation significantly increased the electrical activity of PENs and markedly decreased the electrical activity of PINs. These effects were significantly greater in CCI rats compared to sham rats. EA treatment reduced the effects of the noxious stimulus on PENs and PINs in both sham and CCI rats. The effects of EA treatment could be inhibited by U0126 in sham-operated rats. The results suggest that EA reduces effects of acute sciatic nerve stimulation on PENs and PINs in the CA1 region of the hippocampus of both sham and CCI rats and that the ERK (extracellular regulated kinase) signaling pathway is involved in the modulation of EA analgesia. PMID:27833763

  1. Effect of interaction between acute administration of morphine and cannabinoid compounds on spontaneous excitatory and inhibitory postsynaptic currents of magnocellular neurons of supraoptic nucleus

    PubMed Central

    Yousefpour, Mitra; Naderi, Nima; Motamedi, Fereshteh

    2016-01-01

    Objective(s): Opioids and cannabinoids are two important compounds that have been shown to influence the activity of magnocellular neurons (MCNs) of supraoptic nucleus (SON). The interaction between opioidergic and cannabinoidergic systems in various structures of the brain and spinal cord is now well established, but not in the MCNs of SON. Materials and methods: In this study, whole cell patch clamp recording of neurons in rat brain slice was used to investigate the effect of acute morphine and cannabinoid administration on spontaneous inhibitory and excitatory spostsynaptic currents (sIPSCs and sEPSCs) in MCNs. Results: Bath application of morphine produced an increase in sEPSCs frequency and a decrease in sIPSCs frequency. In contrast, bath application of URB597 (fatty acid amide hydrolase (FAAH) inhibitor) produced a decrease in sEPSCs frequency but an increase in sIPSCs frequency. WIN55212-2 (cannabinoid receptor agonist) decreased both sIPSCs and sEPSCs frequencies of MCNs. Co-application of morphine and URB597 attenuated the effect of morphine on MCNs. Conclusion: Taken together, these data indicated that at the cellular level, pharmacological augmentation of endocannabinoids could attenuate morphine effects on MCNs. PMID:27482350

  2. Adult Bone Marrow Neural Crest Stem Cells and Mesenchymal Stem Cells Are Not Able to Replace Lost Neurons in Acute MPTP-Lesioned Mice

    PubMed Central

    Neirinckx, Virginie; Marquet, Alice; Coste, Cécile

    2013-01-01

    Adult bone marrow stroma contains multipotent stem cells (BMSC) that are a mixed population of mesenchymal and neural-crest derived stem cells. Both cells are endowed with in vitro multi-lineage differentiation abilities, then constituting an attractive and easy-available source of material for cell therapy in neurological disorders. Whereas the in vivo integration and differentiation of BMSC in neurons into the central nervous system is currently matter of debate, we report here that once injected into the striatum of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice, pure populations of either bone marrow neural crest stem cells (NCSC) or mesenchymal stem cells (MSC) survived only transiently into the lesioned brain. Moreover, they do not migrate through the brain tissue, neither modify their initial phenotype, while no recovery of the dopaminergic system integrity was observed. Consequently, we tend to conclude that MSC/NCSC are not able to replace lost neurons in acute MPTP-lesioned dopaminergic system through a suitable integration and/or differentiation process. Altogether with recent data, it appears that neuroprotective, neurotrophic and anti-inflammatory features characterizing BMSC are of greater interest as regards CNS lesions management. PMID:23741377

  3. Acute tianeptine treatment selectively modulates neuronal activation in the central nucleus of the amygdala and attenuates fear extinction.

    PubMed

    Godsil, B P; Bontempi, B; Mailliet, F; Delagrange, P; Spedding, M; Jay, T M

    2015-11-01

    Antidepressant drugs are commonly prescribed treatments for anxiety disorders, and there is growing interest in understanding how these drugs impact fear extinction because extinction learning is pivotal to successful exposure-based therapy (EBT). A key objective within this domain is understanding how antidepressants alter the activation of specific elements of the limbic-based network that governs such fear processing. Chronic treatment with the antidepressant tianeptine has been shown to reduce the acquisition of extinction learning in rats, yet the drug's acute influence on activation in prefrontal and amygdalar regions, and on extinction learning are not well understood. To assess its influence on cellular activation, rats were injected with tianeptine and Fos immunoreactivity was measured in these regions. Acute tianeptine treatment selectively altered Fos expression within subdivisions of the central nucleus of the amygdala (CEA) in a bidirectional manner that varied in relation to ongoing activation within the capsular subdivision and its prefrontal and intra-amygdalar inputs. This pattern of results suggests that the drug can conditionally modulate the activation of CEA subdivisions, which contain microcircuits strongly implicated in fear processing. The effect of acute tianeptine was also examined with respect to the acquisition, consolidation and expression of fear extinction in rats. Acute tianeptine attenuated extinction learning as well as the recall of extinction memory, which underscores that acute dosing with the drug could alter learning during EBT. Together these findings provide a new perspective for understanding the mechanism supporting tianeptine's clinical efficacy, as well as its potential influence on CEA-based learning mechanisms.

  4. Dissociative disorders in medical settings.

    PubMed

    MacPhee, Edward

    2013-10-01

    Despite the challenges of conducting research on dissociation and the dissociative disorders, our understanding has grown greatly over the past three decades, including our knowledge of the often overlooked sensorimotor manifestations of dissociation, more commonly referred to as somatoform dissociation. This article will first review the definitions and presentations of dissociation in general along with recent research on the concept of somatoform dissociation. Then, each of the dissociative disorders and conversion disorder will be discussed in further detail as well as how they might present in a medical setting. Current recommendations for diagnosis and treatment will also be provided.

  5. Peritraumatic dissociation following motor vehicle accidents: relationship to prior trauma and prior major depression.

    PubMed

    Fullerton, C S; Ursano, R J; Epstein, R S; Crowley, B; Vance, K L; Kao, T C; Baum, A

    2000-05-01

    Individuals who dissociate at the time of a traumatic event (peritraumatic dissociation) are more likely to develop acute and chronic posttraumatic stress disorder (PTSD). However, little is known about who is at risk of peritraumatic dissociation. Motor vehicle accident subjects (N = 122) were systematically recruited and followed over 12 months. We used the Structured Clinical Interview for DSM-III-R (SCID) and the Peritraumatic Dissociative Experiences Questionnaire-Rater Version (PDEQ-RV). Younger subjects were more likely to experience peritraumatic dissociation as were white versus nonwhites, and single versus married subjects. Younger subjects reported a greater number of peritraumatic dissociative symptoms as did subjects with an injured passenger. After adjusting for age and passenger injury, prior major depression was significantly related to more peritraumatic dissociative symptoms. An interaction of age and prior major depression indicated that those who were younger and reported a history of major depression had the greatest number of peritraumatic dissociative symptoms.

  6. Dissociation of diatomic gases

    NASA Technical Reports Server (NTRS)

    Hansen, C. F.

    1991-01-01

    The Landau-Zener theory of reactive cross sections has been applied to diatomic molecules dissociating from a ladder of rotational and vibrational states. Although the preexponential factor of the Arrhenius rate expression is shown to be a complex function of the dimensionless activation energy, the average over all states in the ladder is well represented by a single factor that varies about as T exp (-n), where the coefficient n is the order of unity. This relation agrees very well with experimental data for dissociation of O2 and N2, for example. The results validate previous empirical assignment of a single preexponential factor in the Arrhenius expression and justify the extrapolation of the expression well beyond the range of data. The theory is then used to calculate the effect of vibrational nonequilibrium on dissociation rate. For Morse oscillators the results are about the same as for harmonic oscillators, and the dissociation from a ladder of equilibrium rotational and nonequilibrium vibrational states is close to an analytic approximation provided by Hammerling, Kivel, and Teare for harmonic oscillators all dissociating from the ground rotational state.

  7. Redox modulation of A-type K+ currents in pain-sensing dorsal root ganglion neurons.

    PubMed

    Hsieh, Chi-Pan

    2008-06-06

    Redox modulation of fast inactivation has been described in certain cloned A-type voltage-gated K(+) (Kv) channels in expressing systems, but the effects remain to be demonstrated in native neurons. In this study, we examined the effects of cysteine-specific redox agents on the A-type K(+) currents in acutely dissociated small diameter dorsal root ganglion (DRG) neurons from rats. The fast inactivation of most A-type currents was markedly removed or slowed by the oxidizing agents 2,2'-dithio-bis(5-nitropyridine) (DTBNP) and chloramine-T. Dithiothreitol, a reducing agent for the disulfide bond, restored the inactivation. These results demonstrated that native A-type K(+) channels, probably Kv1.4, could switch the roles between inactivating and non-inactivating K(+) channels via redox regulation in pain-sensing DRG neurons. The A-type channels may play a role in adjusting pain sensitivity in response to peripheral redox conditions.

  8. N-Acetylaspartate, a marker of both cellular dysfunction and neuronal loss: its relevance to studies of acute brain injury.

    PubMed

    Demougeot, C; Garnier, P; Mossiat, C; Bertrand, N; Giroud, M; Beley, A; Marie, C

    2001-04-01

    To evaluate the contribution of cellular dysfunction and neuronal loss to brain N-acetylaspartate (NAA) depletion, NAA was measured in brain tissue by HPLC and UV detection in rats subjected to cerebral injury, associated or not with cell death. When lesion was induced by intracarotid injection of microspheres, the fall in NAA was related to the degree of embolization and to the severity of brain oedema. When striatal lesion was induced by local injection of malonate, the larger the lesion volume, the higher the NAA depletion. However, reduction of brain oedema and striatal lesion by treatment with the lipophilic iron chelator dipyridyl (20 mg/kg, 1 h before and every 8 h after embolization) and the inducible nitric oxide synthase inhibitor aminoguanidine (100 mg/kg given 1 h before malonate and then every 9 h), respectively, failed to ameliorate the fall in NAA. Moreover, after systemic administration of 3-nitropropionic acid, a marked reversible fall in NAA striatal content was observed despite the lack of tissue necrosis. Overall results show that cellular dysfunction can cause higher reductions in NAA level than neuronal loss, thus making of NAA quantification a potential tool for visualizing the penumbra area in stroke patients.

  9. SUMOylation of NaV1.2 channels mediates the early response to acute hypoxia in central neurons

    PubMed Central

    Plant, Leigh D; Marks, Jeremy D; Goldstein, Steve AN

    2016-01-01

    The mechanism for the earliest response of central neurons to hypoxia—an increase in voltage-gated sodium current (INa)—has been unknown. Here, we show that hypoxia activates the Small Ubiquitin-like Modifier (SUMO) pathway in rat cerebellar granule neurons (CGN) and that SUMOylation of NaV1.2 channels increases INa. The time-course for SUMOylation of single NaV1.2 channels at the cell surface and changes in INa coincide, and both are prevented by mutation of NaV1.2-Lys38 or application of a deSUMOylating enzyme. Within 40 s, hypoxia-induced linkage of SUMO1 to the channels is complete, shifting the voltage-dependence of channel activation so that depolarizing steps evoke larger sodium currents. Given the recognized role of INa in hypoxic brain damage, the SUMO pathway and NaV1.2 are identified as potential targets for neuroprotective interventions. DOI: http://dx.doi.org/10.7554/eLife.20054.001 PMID:28029095

  10. Psychophysiology of dissociated consciousness.

    PubMed

    Bob, Petr

    2014-01-01

    Recent study of consciousness provides an evidence that there is a limit of consciousness, which presents a barrier between conscious and unconscious processes. This barrier likely is specifically manifested as a disturbance of neural mechanisms of consciousness that through distributed brain processing, attentional mechanisms and memory processes enable to constitute integrative conscious experience. According to recent findings a level of conscious integration may change during certain conditions related to experimental cognitive manipulations, hypnosis, or stressful experiences that can lead to dissociation of consciousness. In psychopathological research the term dissociation was proposed by Pierre Janet for explanation of processes related to splitting of consciousness due to traumatic events or during hypnosis. According to several recent findings dissociation of consciousness likely is related to deficits in global distribution of information and may lead to heightened levels of "neural complexity" that reflects brain integration or differentiation based on numbers of independent neural processes in the brain that may be specifically related to various mental disorders.

  11. Dissociative Spectrum Disorders in the Primary Care Setting

    PubMed Central

    Elmore, James L.

    2000-01-01

    Dissociative disorders have a lifetime prevalence of about 10%. Dissociative symptoms may occur in acute stress disorder, posttraumatic stress disorder, somatization disorder, substance abuse, trance and possession trance, Ganser's syndrome, and dissociative identity disorder, as well as in mood disorders, psychoses, and personality disorders. Dissociative symptoms and disorders are observed frequently among patients attending our rural South Carolina community mental health center. Given the prevalence of mental illness in primary care settings and the diagnostic difficulties encountered with dissociative disorders, such illness may be undiagnosed or misdiagnosed in primary care settings. We developed an intervention model that may be applicable to primary care settings or helpful to primary care physicians. Key points of the intervention are identification of dissociative symptoms, patient and family education, review of the origin of the symptoms as a method of coping with trauma, and supportive reinforcement of cognitive and relaxation skills during follow-up visits. Symptom recognition, Education of the family, Learning new skills, and Follow-up may be remembered by the mnemonic device SELF. We present several cases to illustrate dissociative symptoms and our intervention. Physicians and other professionals using the 4 steps and behavioral approaches will be able to better recognize and triage patients with dissociative symptoms. Behaviors previously thought to be secondary to psychosis or personality disorders may be seen in a new frame of reference, strengthening the therapeutic alliance while reducing distress and acting-out behaviors. PMID:15014580

  12. Processing of cdk5 activator p35 to its truncated form (p25) by calpain in acutely injured neuronal cells.

    PubMed

    Nath, R; Davis, M; Probert, A W; Kupina, N C; Ren, X; Schielke, G P; Wang, K K

    2000-07-21

    Recently, it was shown that conversion of cdk5 activator protein p35 to a C-terminal fragment p25 promotes a deregulation of cdk5 activity, which may contribute to neurodegeneration in Alzheimer's disease. In this study, we present evidence that calpain is a protease involved in the conversion of p35 to p25. To activate calpain, rat cerebellar granule neurons were treated with maitotoxin (MTX). A C-terminus-directed anti-p35 antibody detected that p35 conversion to p25 paralleled the formation of calpain-generated alpha-spectrin (alpha-fodrin) breakdown products (SBDP's) in a maitotoxin-dose-dependent manner. Two calpain inhibitors (MDl28170 and SJA6017) reduced p35 processing but were unchanged when exposed to the caspase inhibitor carbobenzoxy-Asp-CH(2)OC(=O)-2, 6-dichlorobenzene or the proteasome inhibitors (lactacystin and Z-Ile-Glu(OtBu)Ala-Leu-CHO). p35 protein was also degraded to p25 when rat brain lysate was subjected to in vitro digestion with purified mu- and m-calpains. Additionally, in a rat temporary middle cerebral artery occlusion model, p35 processing to p25 again paralleled SBDP formation in the ischemic core. Lastly, in malonate-injured rat brains, the ipsilateral side showed a striking correlation of SBDP formation with p35 to p25 conversion and tau phosphorylation (at Ser202 and Thr205) increase. These data suggest that calpain is a major neuronal protease capable of converting p35 to p25 and might play a pathological role of activating cdk5 and its phosphorylation of tau in Alzheimer's disease.

  13. Mechanisms of sustained high firing rates in two classes of vestibular nucleus neurons: differential contributions of resurgent Na, Kv3, and BK currents.

    PubMed

    Gittis, Aryn H; Moghadam, Setareh H; du Lac, Sascha

    2010-09-01

    To fire at high rates, neurons express ionic currents that work together to minimize refractory periods by ensuring that sodium channels are available for activation shortly after each action potential. Vestibular nucleus neurons operate around high baseline firing rates and encode information with bidirectional modulation of firing rates up to several hundred Hz. To determine the mechanisms that enable these neurons to sustain firing at high rates, ionic currents were measured during firing by using the action potential clamp technique in vestibular nucleus neurons acutely dissociated from transgenic mice. Although neurons from the YFP-16 line fire at rates higher than those from the GIN line, both classes of neurons express Kv3 and BK currents as well as both transient and resurgent Na currents. In the fastest firing neurons, Kv3 currents dominated repolarization at all firing rates and minimized Na channel inactivation by rapidly transitioning Na channels from the open to the closed state. In slower firing neurons, BK currents dominated repolarization at the highest firing rates and sodium channel availability was protected by a resurgent blocking mechanism. Quantitative differences in Kv3 current density across neurons and qualitative differences in immunohistochemically detected expression of Kv3 subunits could account for the difference in firing range within and across cell classes. These results demonstrate how divergent firing properties of two neuronal populations arise through the interplay of at least three ionic currents.

  14. The dissociative recombination of ?

    NASA Astrophysics Data System (ADS)

    Laubé, S.; Lehfaoui, L.; Rowe, B. R.; Mitchell, J. B. A.

    1998-09-01

    The dissociative recombination rate coefficient for 0953-4075/31/18/016/img2 has been measured at 300 K using a flowing afterglow Langmuir probe-mass spectrometer apparatus. A value of 0953-4075/31/18/016/img3 has been found.

  15. Introduction to dissociative recombination

    NASA Technical Reports Server (NTRS)

    Guberman, Steven L.; Mitchell, J. Brian A.

    1989-01-01

    Dissociative recombination (DR) of molecular ions with electrons has important consequences in many areas of physical science. Ab-initio calculations coupled with resonant scattering theory and multichannel quantum defect studies have produced detailed results illuminating the role of ion vibrational excitation, the quantum yields of the DR products, and the role of Rydberg states. The theoretical and experimental results are discussed.

  16. Dissociative Identity Disorder

    ERIC Educational Resources Information Center

    Schmidt, Tom

    2007-01-01

    Few psychological disorders in the Diagnostic Statistical Manual have generated as much controversy as Dissociative Identity Disorder (DID). For the past 35 years diagnoses of DID, previously referred to as Multiple Personality Disorder (MPD), have increased exponentially, causing various psychological researchers and clinicians to question the…

  17. Functional (dissociative) retrograde amnesia.

    PubMed

    Markowitsch, H J; Staniloiu, A

    2017-01-01

    Retrograde amnesia is described as condition which can occur after direct brain damage, but which occurs more frequently as a result of a psychiatric illness. In order to understand the amnesic condition, content-based divisions of memory are defined. The measurement of retrograde memory is discussed and the dichotomy between "organic" and "psychogenic" retrograde amnesia is questioned. Briefly, brain damage-related etiologies of retrograde amnesia are mentioned. The major portion of the review is devoted to dissociative amnesia (also named psychogenic or functional amnesia) and to the discussion of an overlap between psychogenic and "brain organic" forms of amnesia. The "inability of access hypothesis" is proposed to account for most of both the organic and psychogenic (dissociative) patients with primarily retrograde amnesia. Questions such as why recovery from retrograde amnesia can occur in retrograde (dissociative) amnesia, and why long-term new learning of episodic-autobiographic episodes is possible, are addressed. It is concluded that research on retrograde amnesia research is still in its infancy, as the neural correlates of memory storage are still unknown. It is argued that the recollection of episodic-autobiographic episodes most likely involves frontotemporal regions of the right hemisphere, a region which appears to be hypometabolic in patients with dissociative amnesia.

  18. Dissociative Reactions to Incest.

    ERIC Educational Resources Information Center

    Hall, J. Mark

    In contrast to Freud's later and revised view of the etiology of hysterical, or dissociative, symptoms, it is now known that real, and not fantasized, sexual experiences in childhood are experienced in disociative symptomatology. It is useful to understand that incest involves both traumatic events, that is, incidents of sexual violation per se,…

  19. Pathological Dissociation as Measured by the Child Dissociative Checklist

    ERIC Educational Resources Information Center

    Wherry, Jeffrey N.; Neil, Debra A.; Taylor, Tamara N.

    2009-01-01

    The component structure of the Child Dissociative Checklist was examined among abused children. A factor described as pathological dissociation emerged that was predicted by participants being male. There also were differences in pathological dissociation between groups of sexually abused and physically abused children. Replication of this factor…

  20. Dissociation and psychosis in dissociative identity disorder and schizophrenia.

    PubMed

    Laddis, Andreas; Dell, Paul F

    2012-01-01

    Dissociative symptoms, first-rank symptoms of schizophrenia, and delusions were assessed in 40 schizophrenia patients and 40 dissociative identity disorder (DID) patients with the Multidimensional Inventory of Dissociation (MID). Schizophrenia patients were diagnosed with the Structured Clinical Interview for the DSM-IV Axis I Disorders; DID patients were diagnosed with the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised. DID patients obtained significantly (a) higher dissociation scores; (b) higher passive-influence scores (first-rank symptoms); and (c) higher scores on scales that measure child voices, angry voices, persecutory voices, voices arguing, and voices commenting. Schizophrenia patients obtained significantly higher delusion scores than did DID patients. What is odd is that the dissociation scores of schizophrenia patients were unrelated to their reports of childhood maltreatment. Multiple regression analyses indicated that 81% of the variance in DID patients' dissociation scores was predicted by the MID's Ego-Alien Experiences Scale, whereas 92% of the variance in schizophrenia patients' dissociation scores was predicted by the MID's Voices Scale. We propose that schizophrenia patients' responses to the MID do not index the same pathology as do the responses of DID patients. We argue that neither phenomenological definitions of dissociation nor the current generation of dissociation instruments (which are uniformly phenomenological in nature) can distinguish between the dissociative phenomena of DID and what we suspect are just the dissociation-like phenomena of schizophrenia.

  1. High-threshold, Kv3-like potassium currents in magnocellular neurosecretory neurons and their role in spike repolarization.

    PubMed

    Shevchenko, Talent; Teruyama, Ryoichi; Armstrong, William E

    2004-11-01

    We identified Kv3-like high-threshold K+ currents in hypothalamic supraoptic neurons using whole cell recordings in hypothalamic slices and in acutely dissociated neurons. Tetraethylammonium (TEA)-sensitive currents (< 1 mM TEA) evoked from -50 mV were characterized by a large component that inactivated in 10-30 ms, and a smaller, persistent component that inactivated in 1-2 s. I/V relations in dissociated neurons revealed TEA-subtracted currents with a slope and voltage dependency consistent with the presence of Kv3-like channels. In slices, tests with 0.01-0.7 mM TEA produced an IC50 of 200-300 nM for both fast and persistent currents. The fast transient current was similar to currents associated with the expression of Kv3.4 subunits, given that it was sensitive to BDS-I (100 nM). The persistent TEA-sensitive current appeared similar to those attributed to Kv3.1/3.2 subunits. Although qualitatively similar, oxytocin (OT) and vasopressin (VP) neurons in slices differed in the stronger presence of persistent current in VP neurons. In both cell types, the IC50 for TEA-induced spike broadening was similar to that observed for current suppression in voltage clamp. However, TEA had a greater effect on the spike width of VP neurons than of OT neurons. Immunochemical studies revealed a stronger expression of the Kv3.1b alpha-subunit in VP neurons, which may be related to the greater importance of this current type in VP spike repolarization. Because OT and VP neurons are not considered fast firing, but do exhibit frequency- and calcium-dependent spike broadening, Kv3-like currents may be important for maintaining spike width and calcium influx within acceptable limits during repetitive firing.

  2. Three dimensions of dissociative amnesia.

    PubMed

    Dell, Paul F

    2013-01-01

    Principal axis factor analysis with promax rotation extracted 3 factors from the 42 memory and amnesia items of the Multidimensional Inventory of Dissociation (MID) database (N = 2,569): Discovering Dissociated Actions, Lapses of Recent Memory and Skills, and Gaps in Remote Memory. The 3 factors' shared variance ranged from 36% to 64%. Construed as scales, the 3 factor scales had Cronbach's alpha coefficients of .96, .94, and .93, respectively. The scales correlated strongly with mean Dissociative Experiences Scale scores, mean MID scores, and total scores on the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised (SCID-D-R). What is interesting is that the 3 amnesia factors exhibited a range of correlations with SCID-D-R Amnesia scores (.52, .63, and .70, respectively), suggesting that the SCID-D-R Amnesia score emphasizes gaps in remote memory over amnesias related to dissociative identity disorder. The 3 amnesia factor scales exhibited a clinically meaningful pattern of significant differences among dissociative identity disorder, dissociative disorder not otherwise specified-1, dissociative amnesia, depersonalization disorder, and nonclinical participants. The 3 amnesia factors may have greater clinical utility for frontline clinicians than (a) amnesia as discussed in the context of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, nosology of the dissociative disorders or (b) P. Janet's (1893/1977 ) 4-fold classification of dissociative amnesia. The author recommends systematic study of the phenomenological differences within specific dissociative symptoms and their differential relationship to specific dissociative disorders.

  3. The Corticostriatal System in Dissociated Cell Culture

    PubMed Central

    Randall, Fiona E.; Garcia-Munoz, Marianela; Vickers, Catherine; Schock, Sarah C.; Staines, William A.; Arbuthnott, Gordon W.

    2011-01-01

    The sparse connectivity within the striatum in vivo makes the investigation of individual corticostriatal synapses very difficult. Most studies of the corticostriatal input have been done using electrical stimulation under conditions where it is hard to identify the precise origin of the cortical input. We have employed an in vitro dissociated cell culture system that allows the identification of individual corticostriatal pairs and have been developing methods to study individual neuron inputs to striatal neurons. In mixed corticostriatal cultures, neurons had resting activity similar to the system in vivo. Up/down states were obvious and seemed to encompass the entire culture. Mixed cultures of cortical neurons from transgenic mice expressing green fluorescent protein with striatal neurons from wild-type mice of the same developmental stage allowed visual identification of individual candidate corticostriatal pairs. Recordings were performed between 12 and 37 days in vitro (DIV). To investigate synaptic connections we recorded from 69 corticostriatal pairs of which 44 were connected in one direction and 25 reciprocally. Of these connections 41 were corticostriatal (nine inhibitory) and 53 striatocortical (all inhibitory). The observed excitatory responses were of variable amplitude (−10 to −370 pA, n = 32). We found the connections very secure – with negligible failures on repeated stimulation (approximately 1 Hz) of the cortical neuron. Inhibitory corticostriatal responses were also observed (−13 to −314 pA, n = 9). Possibly due to the mixed type of culture we found an inhibitory striatocortical response (−14 to −598 pA, n = 53). We are now recording from neurons in separate compartments to more closely emulate neuroanatomical conditions but still with the possibility of the easier identification of the connectivity. PMID:21743806

  4. Acute Cocaine Induces Fast Activation of D1 Receptor and Progressive Deactivation of D2 Receptor Strial Neurons: In Vivo Optical Microprobe [Ca(superscript)2+]subscript)i Imaging

    SciTech Connect

    Du, C.; Luo, Z.; Volkow, N.D.; Heintz, N.; Pan, Y.; Du, C.

    2011-09-14

    Cocaine induces fast dopamine increases in brain striatal regions, which are recognized to underlie its rewarding effects. Both dopamine D1 and D2 receptors are involved in cocaine's reward but the dynamic downstream consequences of cocaine effects in striatum are not fully understood. Here we used transgenic mice expressing EGFP under the control of either the D1 receptor (D1R) or the D2 receptor (D2R) gene and microprobe optical imaging to assess the dynamic changes in intracellular calcium ([Ca{sup 2+}]{sub i} ) responses (used as marker of neuronal activation) to acute cocaine in vivo separately for D1R- versus D2R-expressing neurons in striatum. Acute cocaine (8 mg/kg, i.p.) rapidly increased [Ca{sup 2+}]{sub i} in D1R-expressing neurons (10.6 {+-} 3.2%) in striatum within 8.3 {+-} 2.3 min after cocaine administration after which the increases plateaued; these fast [Ca{sup 2+}]{sub i} increases were blocked by pretreatment with a D1R antagonist (SCH23390). In contrast, cocaine induced progressive decreases in [Ca{sup 2+}]{sub i} in D2R-expressing neurons (10.4 {+-} 5.8%) continuously throughout the 30 min that followed cocaine administration; these slower [Ca{sup 2+}]{sub i} decreases were blocked by pretreatment with a D2R antagonist (raclopride). Since activation of striatal D1R-expressing neurons (direct-pathway) enhances cocaine reward, whereas activation of D2R expressing neurons suppresses it (indirect-pathway) (Lobo et al., 2010), this suggests that cocaine's rewarding effects entail both its fast stimulation ofD1R (resulting in abrupt activation of direct-pathway neurons) and a slower stimulation of D2R (resulting in longer-lasting deactivation of indirect-pathway neurons). We also provide direct in vivo evidence of D2R and D1R interactions in the striatal responses to acute cocaine administration.

  5. Imagining the impossible before breakfast: the relation between creativity, dissociation, and sleep

    PubMed Central

    van Heugten - van der Kloet, Dalena; Cosgrave, Jan; Merckelbach, Harald; Haines, Ross; Golodetz, Stuart; Lynn, Steven Jay

    2015-01-01

    Dissociative symptoms have been related to higher rapid eye movement sleep density, a sleep phase during which hyperassociativity may occur. This may enhance artistic creativity during the day. To test this hypothesis, we conducted a creative photo contest to explore the relation between dissociation, sleep, and creativity. During the contest, participants (N = 72) took one photo per day for five consecutive days, based on specific daily themes (consisting of single words) and the instruction to take as creative a photo as possible each day. Furthermore, they completed daily measures of state dissociation and a short sleep diary. The photos and their captions were ranked by two professional photographers and two clinical psychologists based on creativity, originality, bizarreness, and quality. We expected that dissociative people would rank higher in the contest compared with low-dissociative participants, and that the most original photos would be taken on days when the participants scored highest on acute dissociation. We found that acute dissociation predicted a higher ranking on creativity. Poorer sleep quality and fewer hours of sleep predicted more bizarreness in the photos and captions. None of the trait measures could predict creativity. In sum, acute dissociation related to enhanced creativity. These findings contribute to our understanding of dissociative symptomatology. PMID:25859231

  6. Neurotensin excitation of serotonergic neurons in the rat nucleus raphe magnus: ionic and molecular mechanisms.

    PubMed

    Li, A H; Yeh, T H; Tan, P P; Hwang, H M; Wang, H L

    2001-06-01

    To understand the cellular and molecular mechanisms by which neurotensin (NT) induces an analgesic effect in the nucleus raphe magnus (NRM), whole-cell patch-clamp recordings were performed to investigate the electrophysiological effects of NT on acutely dissociated NRM neurons. Two subtypes of neurons, primary serotonergic and secondary non-serotonergic cells, were identified from acutely isolated NRM neurons. During current-clamp recordings, NT depolarized NRM serotonergic neurons and evoked action potentials. Voltage-clamp recordings showed that NT excited serotonergic neurons by enhancing a voltage-insensitive and non-selective cationic conductance. Both SR48692, a selective antagonist of subtype 1 neurotensin receptor (NTR-1), and SR 142948A, a non-selective antagonist of NTR-1 and subtype 2 neurotensin receptor (NTR-2), failed to prevent neurotensin from exciting NRM serotonergic neurons. NT-evoked cationic current was inhibited by the intracellular administration of GDP-beta-S. NT failed to induce cationic currents after dialyzing serotonergic neurons with the anti-G(alphaq/11) antibody. Cellular Ca(2+) imaging study using fura-2 showed that NT induced the calcium release from the intracellular store. NT-evoked current was blocked after the internal perfusion of heparin, an IP(3) receptor antagonist, or BAPTA, a fast Ca(2+) chelator. It is concluded that neurotensin enhancement of the cationic conductance of NRM serotonergic neurons is mediated by a novel subtype of neurotensin receptors. The coupling mechanism via G(alphaq/11) proteins is likely to involve the generation of IP(3), and subsequent IP(3)-evoked Ca(2+) release from intracellular stores results in activating the non-selective cationic conductance.

  7. Dissociation: cognitive capacity or dysfunction?

    PubMed

    de Ruiter, Michiel B; Elzinga, Bernet M; Phaf, R Hans

    2006-01-01

    Dissociative experiences are mostly studied as a risk factor for dissociative pathology. Nonpathological dissociation is quite common in the general population, however, and may reflect a constitutionally determined cognitive style rather than a pathological trait acquired through the experience of adverse life events. In a theoretical model, we propose that nonpathological dissociation is characterized by high levels of elaboration learning and reconstructive retrieval, for which enhanced levels of attentional and working memory abilities are a prerequisite. These characteristics, in general, seem to be representative for a higher ability to (re-)construct conscious experiences. We review some of our behavioral as well as neural (i.e., fMRI, ERPs) studies, suggesting that high dissociative individuals are characterized by heightened levels of attention, working memory and episodic memory. In nonpathological conditions a person may benefit from these dissociative abilities, although after adverse (e.g., traumatic) events the disposition may develop into dissociative pathology.

  8. TRESK channel contribution to nociceptive sensory neurons excitability: modulation by nerve injury

    PubMed Central

    2011-01-01

    Background Neuronal hyperexcitability is a crucial phenomenon underlying spontaneous and evoked pain. In invertebrate nociceptors, the S-type leak K+ channel (analogous to TREK-1 in mammals) plays a critical role of in determining neuronal excitability following nerve injury. Few data are available on the role of leak K2P channels after peripheral axotomy in mammals. Results Here we describe that rat sciatic nerve axotomy induces hyperexcitability of L4-L5 DRG sensory neurons and decreases TRESK (K2P18.1) expression, a channel with a major contribution to total leak current in DRGs. While the expression of other channels from the same family did not significantly change, injury markers ATF3 and Cacna2d1 were highly upregulated. Similarly, acute sensory neuron dissociation (in vitro axotomy) produced marked hyperexcitability and similar total background currents compared with neurons injured in vivo. In addition, the sanshool derivative IBA, which blocked TRESK currents in transfected HEK293 cells and DRGs, increased intracellular calcium in 49% of DRG neurons in culture. Most IBA-responding neurons (71%) also responded to the TRPV1 agonist capsaicin, indicating that they were nociceptors. Additional evidence of a biological role of TRESK channels was provided by behavioral evidence of pain (flinching and licking), in vivo electrophysiological evidence of C-nociceptor activation following IBA injection in the rat hindpaw, and increased sensitivity to painful pressure after TRESK knockdown in vivo. Conclusions In summary, our results clearly support an important role of TRESK channels in determining neuronal excitability in specific DRG neurons subpopulations, and show that axonal injury down-regulates TRESK channels, therefore contributing to neuronal hyperexcitability. PMID:21527011

  9. Segregation and Crosstalk of D1 Receptor-Mediated Activation of ERK in Striatal Medium Spiny Neurons upon Acute Administration of Psychostimulants

    PubMed Central

    Gutierrez-Arenas, Omar; Eriksson, Olivia; Hellgren Kotaleski, Jeanette

    2014-01-01

    The convergence of corticostriatal glutamate and dopamine from the midbrain in the striatal medium spiny neurons (MSN) triggers synaptic plasticity that underlies reinforcement learning and pathological conditions such as psychostimulant addiction. The increase in striatal dopamine produced by the acute administration of psychostimulants has been found to activate not only effectors of the AC5/cAMP/PKA signaling cascade such as GluR1, but also effectors of the NMDAR/Ca2+/RAS cascade such as ERK. The dopamine-triggered effects on both these cascades are mediated by D1R coupled to Golf but while the phosphorylation of GluR1 is affected by reductions in the available amount of Golf but not of D1R, the activation of ERK follows the opposite pattern. This segregation is puzzling considering that D1R-induced Golf activation monotonically increases with DA and that there is crosstalk from the AC5/cAMP/PKA cascade to the NMDAR/Ca2+/RAS cascade via a STEP (a tyrosine phosphatase). In this work, we developed a signaling model which accounts for this segregation based on the assumption that a common pool of D1R and Golf is distributed in two D1R/Golf signaling compartments. This model integrates a relatively large amount of experimental data for neurons in vivo and in vitro. We used it to explore the crosstalk topologies under which the sensitivities of the AC5/cAMP/PKA signaling cascade to reductions in D1R or Golf are transferred or not to the activation of ERK. We found that the sequestration of STEP by its substrate ERK together with the insensitivity of STEP activity on targets upstream of ERK (i.e. Fyn and NR2B) to PKA phosphorylation are able to explain the experimentally observed segregation. This model provides a quantitative framework for simulation based experiments to study signaling required for long term potentiation in MSNs. PMID:24499932

  10. Dissociative absorption: An empirically unique, clinically relevant, dissociative factor.

    PubMed

    Soffer-Dudek, Nirit; Lassri, Dana; Soffer-Dudek, Nir; Shahar, Golan

    2015-11-01

    Research of dissociative absorption has raised two questions: (a) Is absorption a unique dissociative factor within a three-factor structure, or a part of one general dissociative factor? Even when three factors are found, the specificity of the absorption factor is questionable. (b) Is absorption implicated in psychopathology? Although commonly viewed as "non-clinical" dissociation, absorption was recently hypothesized to be specifically associated with obsessive-compulsive symptoms. To address these questions, we conducted exploratory and confirmatory factor analyses on 679 undergraduates. Analyses supported the three-factor model, and a "purified" absorption scale was extracted from the original inclusive absorption factor. The purified scale predicted several psychopathology scales. As hypothesized, absorption was a stronger predictor of obsessive-compulsive symptoms than of general psychopathology. In addition, absorption was the only dissociative scale that longitudinally predicted obsessive-compulsive symptoms. We conclude that absorption is a unique and clinically relevant dissociative tendency that is particularly meaningful to obsessive-compulsive symptoms.

  11. Dissociation of motor maturation.

    PubMed

    DiMario, Francis J

    2003-06-01

    We prospectively acquired clinical data regarding the presentation, evaluation, and developmental progress of all patients identified with dissociated motor maturation to define their clinical outcomes. Children (N = 8) referred for evaluation of suspected cerebral palsy because of delayed sitting or walking and identified to have dissociated motor maturation were followed with serial clinical examination. All displayed the characteristic "sitting on air" posture while held in vertical suspension and had otherwise normal developmental assessments. This posture is composed of the hips held in flexion and abduction with the knees extended and feet plantar or dorsiflexed. Three children were initially evaluated at 10 months of age owing to absence of sitting and five other children were evaluated at a mean of 14 months (range 12-19 months) owing to inability to stand. Follow-up evaluations were conducted over a mean of 10.5 months (range 5-34 months). Five children were born prematurely at 34 to 36 weeks gestation. Denver Developmental Screening Test and general and neurologic examinations were normal except to note hypotonia in six children and the "sitting on air" posture in all of the children. Four children have older siblings or parents who "walked late" (after 15 months). On average, the children attained sitting by 8 months (range 7-10 months). One child did not crawl prior to independent walking, two children scooted rather than crawled, and five children crawled at an average of 13.5 months (range 10-16 months). All children cruised by a mean of 18 months (range 16-21.5 months) and attained independent walking by 20.1 months (range 18-25 months). Neuroimaging and serum creatine kinase enzyme testing were normal in two children who were tested. These eight children conform to the syndrome of dissociated motor maturation. The "sitting on air" posture serves as a diagnostic sign and anticipated excellent prognosis, but follow-up is required to ensure a normal

  12. Effect of persistent monoarthritis of the temporomandibular joint region on acute mustard oil-induced excitation of trigeminal subnucleus caudalis neurons in male and female rats.

    PubMed

    Bereiter, David A; Okamoto, Keiichiro; Bereiter, Dominique F

    2005-09-01

    The effect of persistent inflammation of the temporomandibular (TMJ) region on Fos-like immunoreactivity (Fos-LI) evoked by acute noxious stimulation of the same or opposite TMJ was assessed in male and cycling female rats. Two weeks after inflammation of the TMJ by complete Freund's adjuvant (CFA, 25 microg) the selective small fiber excitant, mustard oil (MO, 20%), was injected into the arthritic or opposite TMJ under barbiturate anesthesia. MO stimulation of the arthritic TMJ increased Fos-LI ipsilateral, but not contralateral, to MO compared to naïve subjects in superficial laminae at the trigeminal subnucleus caudalis/upper cervical cord (Vc/C2) junction independent of sex hormone status. Unexpectedly, MO stimulation of the opposite TMJ in arthritic rats also produced a greater Fos-LI response ipsilateral to MO than naïve animals. Fos-LI produced in the dorsal paratrigeminal region (dPa5) and Vc/C2 junction after MO stimulation of the normal TMJ was significantly greater in proestrous than diestrous females or male monoarthritic rats. In contrast to naïve animals, Fos-LI was produced in deep laminae at the Vc/C2 junction ipsilateral to MO in CFA-treated animals independent of the site of prior CFA inflammation or sex hormone status. These results indicated that persistent monoarthritis of the TMJ region enhanced the excitability of trigeminal brainstem neurons to subsequent TMJ injury that occurred bilaterally in multiple regions of the lower trigeminal brainstem complex and depended on sex hormone status.

  13. Acute effect of ethanol on the pattern of behavioural specialization of neurons in the limbic cortex of the freely moving rabbit.

    PubMed

    Alexandrov YuI; Grinchenko YuV; Laukka, S; Järvilehto, T; Maz, V N; Svetlajev, I A

    1990-10-01

    Single-unit activity was studied in the limbic cortex of eight freely moving rabbits in order to find out what kind of changes in the organization of unit activity correlate with behavioural disturbances following an acute administration of ethanol (1 g kg-1). The rabbits were taught to acquire food by pressing pedals in the experimental cage. Unit activity was recorded during this behaviour in a control experiment and the alcohol experiment took place the next day. The number of behavioural mistakes significantly increased in the alcohol experiments. The pattern of behavioural specialization of the units also differed between the control and alcohol experiments. In the control experiments 55% of units did not show any constant activations in relation to the behavioural phases (non-involved units), 28% of the units were constantly activated in relation to one or more behavioural phases learned in the cage (e.g. use of pedals; L units) and 17% of units showed activations in relation to the behaviour learned before the teaching of food acquisition (e.g. movements in general; M units). In the alcohol experiments the number of active units decreased by one-third compared with that found in the control experiments. The relative number of non-involved units did not change, whereas the relation between L and M units was reversed (11% L units and 34% M units). This was the result of a decrease in the number of active L units, mainly in the upper layers of the cortex. The results indicate that ethanol has a selective depressing effect on cortical neurons with different behavioural specialization, which could explain the behavioural disturbances observed in the alcohol experiments.

  14. Redox-Dependent Modulation of T-Type Ca2+ Channels in Sensory Neurons Contributes to Acute Anti-Nociceptive Effect of Substance P

    PubMed Central

    Huang, Dongyang; Huang, Sha; Gao, Haixia; Liu, Yani; Qi, Jinlong; Chen, Pingping; Wang, Caixue; Scragg, Jason L.; Vakurov, Alexander; Peers, Chris; Du, Xiaona

    2016-01-01

    Abstract Aims: Neuropeptide substance P (SP) is produced and released by a subset of peripheral sensory neurons that respond to tissue damage (nociceptors). SP exerts excitatory effects in the central nervous system, but peripheral SP actions are still poorly understood; therefore, here, we aimed at investigating these peripheral mechanisms. Results: SP acutely inhibited T-type voltage-gated Ca2+ channels in nociceptors. The effect was mediated by neurokinin 1 (NK1) receptor-induced stimulation of intracellular release of reactive oxygen species (ROS), as it can be prevented or reversed by the reducing agent dithiothreitol and mimicked by exogenous or endogenous ROS. This redox-mediated T-type Ca2+ channel inhibition operated through the modulation of CaV3.2 channel sensitivity to ambient zinc, as it can be prevented or reversed by zinc chelation and mimicked by exogenous zinc. Elimination of the zinc-binding site in CaV3.2 rendered the channel insensitive to SP-mediated inhibition. Importantly, peripherally applied SP significantly reduced bradykinin-induced nociception in rats in vivo; knock-down of CaV3.2 significantly reduced this anti-nociceptive effect. This atypical signaling cascade shared the initial steps with the SP-mediated augmentation of M-type K+ channels described earlier. Innovation: Our study established a mechanism underlying the peripheral anti-nociceptive effect of SP whereby this neuropeptide produces ROS-dependent inhibition of pro-algesic T-type Ca2+ current and concurrent enhancement of anti-algesic M-type K+ current. These findings will lead to a better understanding of mechanisms of endogenous analgesia. Conclusion: SP modulates T-type channel activity in nociceptors by a redox-dependent tuning of channel sensitivity to zinc; this novel modulatory pathway contributes to the peripheral anti-nociceptive effect of SP. Antioxid. Redox Signal. 25, 233–251. PMID:27306612

  15. Lidocaine Inhibits HCN Currents in Rat Spinal Substantia Gelatinosa Neurons

    PubMed Central

    Hu, Tao; Liu, Nana; Lv, Minhua; Ma, Longxian; Peng, Huizhen; Peng, Sicong

    2016-01-01

    BACKGROUND: Lidocaine, which blocks voltage-gated sodium channels, is widely used in surgical anesthesia and pain management. Recently, it has been proposed that the hyperpolarization-activated cyclic nucleotide (HCN) channel is one of the other novel targets of lidocaine. Substantia gelatinosa in the spinal dorsal horn, which plays key roles in modulating nociceptive information from primary afferents, comprises heterogeneous interneurons that can be electrophysiologically categorized by firing pattern. Our previous study demonstrated that a substantial proportion of substantia gelatinosa neurons reveal the presence of HCN current (Ih); however, the roles of lidocaine and HCN channel expression in different types of substantia gelatinosa neurons remain unclear. METHODS: By using the whole-cell patch-clamp technique, we investigated the effect of lidocaine on Ih in rat substantia gelatinosa neurons of acute dissociated spinal cord slices. RESULTS: We found that lidocaine rapidly decreased the peak Ih amplitude with an IC50 of 80 μM. The inhibition rate on Ih was not significantly different with a second application of lidocaine in the same neuron. Tetrodotoxin, a sodium channel blocker, did not affect lidocaine’s effect on Ih. In addition, lidocaine shifted the half-activation potential of Ih from −109.7 to −114.9 mV and slowed activation. Moreover, the reversal potential of Ih was shifted by −7.5 mV by lidocaine. In the current clamp, lidocaine decreased the resting membrane potential, increased membrane resistance, delayed rebound depolarization latency, and reduced the rebound spike frequency. We further found that approximately 58% of substantia gelatinosa neurons examined expressed Ih, in which most of them were tonically firing. CONCLUSIONS: Our studies demonstrate that lidocaine strongly inhibits Ih in a reversible and concentration-dependent manner in substantia gelatinosa neurons, independent of tetrodotoxin-sensitive sodium channels. Thus, our

  16. Dissociative Electron Attachment

    NASA Astrophysics Data System (ADS)

    Arreola, Esmeralda; Esmeralda Arreola Collaboration; Leigh Hargreaves Collaboration

    Since the pioneering work of Boudiaffa et al., it has been understood that electrons, even with energies near or below the ionization threshold, are capable of initiating strand-breaks in human DNA. This discovery raised important questions for cancer treatments, since sub-ionizing electrons are known to be the most copiously produced secondary product of radiation therapy. But even to date these factors are largely excluded from dosimetry calculations. This lack of inclusion is, at least in part, certainly due to the dearth of fundamental data describing low-energy electron interactions with nucleotide molecules that form the basis of DNA. Understanding of how such slow electrons are able to damage DNA remains incomplete, but the strongly peaked nature of Boudiaffa et al.'s data gives strong hints at resonantly driven collision processes. DNA damage is therefore most likely driven by ``dissociative electron attachment'' (DEA). DEA is a rather complicated process to model due to the coupling of electronic and nuclear degrees of freedom in the molecule. At the California State University Fullerton, we are currently commissioning a new spectrometer to study dissociation channels, reaction rates and orientation effects in DEA collisions between slow electrons and nucleotide molecules. At the meeting we will present design parameters and commissioning data for this new apparatus.

  17. [Dissociative disorders and affective disorders].

    PubMed

    Montant, J; Adida, M; Belzeaux, R; Cermolacce, M; Pringuey, D; Da Fonseca, D; Azorin, J-M

    2014-12-01

    The phenomenology of dissociative disorders may be complex and sometimes confusing. We describe here two cases who were initially misdiagnosed. The first case concerned a 61 year-old woman, who was initially diagnosed as an isolated dissociative fugue and was actually suffering from severe major depressive episode. The second case concerned a 55 year-old man, who was suffering from type I bipolar disorder and polyvascular disease, and was initially diagnosed as dissociative fugue in a mooddestabilization context, while it was finally a stroke. Yet dissociative disorders as affective disorder comorbidity are relatively unknown. We made a review on this topic. Dissociative disorders are often studied through psycho-trauma issues. Litterature is rare on affective illness comorbid with dissociative disorders, but highlight the link between bipolar and dissociative disorders. The later comorbidity often refers to an early onset subtype with also comorbid panic and depersonalization-derealization disorder. Besides, unipolar patients suffering from dissociative symptoms have more often cyclothymic affective temperament. Despite the limits of such studies dissociative symptoms-BD association seems to correspond to a clinical reality and further works on this topic may be warranted.

  18. Activation of protease activated receptor 1 increases the excitability of the dentate granule neurons of hippocampus

    PubMed Central

    2011-01-01

    Protease activated receptor-1 (PAR1) is expressed in multiple cell types in the CNS, with the most prominent expression in glial cells. PAR1 activation enhances excitatory synaptic transmission secondary to the release of glutamate from astrocytes following activation of astrocytically-expressed PAR1. In addition, PAR1 activation exacerbates neuronal damage in multiple in vivo models of brain injury in a manner that is dependent on NMDA receptors. In the hippocampal formation, PAR1 mRNA appears to be expressed by a subset of neurons, including granule cells in the dentate gyrus. In this study we investigate the role of PAR activation in controlling neuronal excitability of dentate granule cells. We confirm that PAR1 protein is expressed in neurons of the dentate cell body layer as well as in astrocytes throughout the dentate. Activation of PAR1 receptors by the selective peptide agonist TFLLR increased the intracellular Ca2+ concentration in a subset of acutely dissociated dentate neurons as well as non-neuronal cells. Bath application of TFLLR in acute hippocampal slices depolarized the dentate gyrus, including the hilar region in wild type but not in the PAR1-/- mice. PAR1 activation increased the frequency of action potential generation in a subset of dentate granule neurons; cells in which PAR1 activation triggered action potentials showed a significant depolarization. The activation of PAR1 by thrombin increased the amplitude of NMDA receptor-mediated component of EPSPs. These data suggest that activation of PAR1 during normal function or pathological conditions, such as during ischemia or hemorrhage, can increase the excitability of dentate granule cells. PMID:21827709

  19. Mechanisms of protease-activated receptor 2-evoked hyperexcitability of nociceptive neurons innervating the mouse colon

    PubMed Central

    Kayssi, Ahmed; Amadesi, Silvia; Bautista, Francisco; Bunnett, Nigel W; Vanner, Stephen

    2007-01-01

    Agonists of protease-activated receptor 2 (PAR2) evoke hyperexcitability of dorsal root ganglia (DRG) neurons by unknown mechanisms. We examined the cellular mechanisms underlying PAR2-evoked hyperexcitability of mouse colonic DRG neurons to determine their potential role in pain syndromes such as visceral hyperalgesia. Colonic DRG neurons were identified by injecting Fast Blue and DiI retrograde tracers into the mouse colon. Using immunofluorescence, we found that DiI-labelled neurons contained PAR2 immunoreactivity, confirming the presence of receptors on colonic neurons. Whole-cell current-clamp recordings of acutely dissociated neurons demonstrated that PAR2 activation with a brief application (3 min) of PAR2 agonists, SLIGRL-NH2 and trypsin, evoked sustained depolarizations (up to 60 min) which were associated with increased input resistance and a marked reduction in rheobase (50% at 30 min). In voltage clamp, SLIGRL-NH2 markedly suppressed delayed rectifier IK currents (55% at 10 min), but had no effect on the transient IA current or TTX-resistant Na+ currents. In whole-cell current-clamp recordings, the sustained excitability evoked by PAR2 activation was blocked by the PKC inhibitor, calphostin, and the ERK1/2 inhibitor PD98059. Studies of ERK1/2 phosphorylation using confocal microscopy demonstrated that SLIGRL-NH2 increased levels of immunoreactive pERK1/2 in DRG neurons, particularly in proximity to the plasma membrane. Thus, activation of PAR2 receptors on colonic nociceptive neurons causes sustained hyperexcitability that is related, at least in part, to suppression of delayed rectifier IK currents. Both PKC and ERK1/2 mediate the PAR2-induced hyperexcitability. These studies describe a novel mechanism of sensitization of colonic nociceptive neurons that may be implicated in conditions of visceral hyperalgesia such as irritable bowel syndrome. PMID:17289784

  20. Hyperglycemia associated dissociative fugue (organic dissociative disorder) in an elderly.

    PubMed

    Ram, Dushad; Ashoka, H G; Gowdappa, Basavnna

    2015-01-01

    Inadequate glycemic control in patients with diabetes is known to be associated with psychiatric disorders such as depression, anxiety disorder, and cognitive impairment. However, dissociative syndrome has not been reported so far. Here we are reporting a case of repeated dissociative fugue associated with hyperglycemia, in an elderly with type II diabetes. Possible neurobiological mechanism has been discussed.

  1. Dissociative States and Neural Complexity

    ERIC Educational Resources Information Center

    Bob, Petr; Svetlak, Miroslav

    2011-01-01

    Recent findings indicate that neural mechanisms of consciousness are related to integration of distributed neural assemblies. This neural integration is particularly vulnerable to past stressful experiences that can lead to disintegration and dissociation of consciousness. These findings suggest that dissociation could be described as a level of…

  2. The latent structure of the Peritraumatic Dissociative Experiences Questionnaire.

    PubMed

    Brooks, Robert; Bryant, Richard A; Silove, Derrick; Creamer, Mark; O'Donnell, Meaghan; McFarlane, Alexander C; Marmar, Charles R

    2009-04-01

    This paper has been retracted due to a publisher's error: the order of the authors was incorrect. The Editor and Publisher of the Journal of Traumatic Stress apologize to the authors and our readership. The Peritraumatic Dissociative Experiences Questionnaire (PDEQ) is a widely used measure of peritraumatic dissociation, and is presumably a unidimensional construct. Two hundred forty-seven individuals admitted to five hospitals after traumatic injury were administered the Clinician Administered PTSD Scale, the Hospital Anxiety and Depression Scale, and the PDEQ. Factor analysis indicated that the PDEQ involved two factors containing four items each: one factor (altered awareness) indexes alterations in awareness and the other (derealization) reflects distortions in perceptions of the self and the world. Only the derealization factor was associated with acute stress, anxiety, and depression symptoms. Cross-validation with independent data provided only partial support for the 2-factor structure model. These data indicate that peritraumatic dissociation may involve two distinct constructs.

  3. Differential properties of type I and type II benzodiazepine receptors in mammalian CNS neurones.

    PubMed Central

    Yakushiji, T.; Shirasaki, T.; Munakata, M.; Hirata, A.; Akaike, N.

    1993-01-01

    1. The effects of benzodiazepine receptor (BZR) partial agonists, Y-23684 and CL218,872, were compared with its full agonist, diazepam, on gamma-aminobutyric acid (GABA)-induced Cl- current (ICl) in acutely dissociated rat cerebral cortex (CTX), cerebellar Purkinje (CPJ) and spinal ventral horn (SVH) neurones, by the whole-cell mode patch-clamp technique. 2. The GABA-induced responses were essentially the same in both SVH and CPJ neurones, but the KD value of the GABA response in CTX neurone was lower than those in the other two brain regions. 3. Enhancement of the GABA response by the two partial agonists was about one-third of that by diazepam in the SVH neurones (where type II subtype of BZR, BZ2, is predominant), whereas these partial agonists potentiated the GABA response as much as diazepam in CPJ neurones (where the type I subtype of BZR, BZ1, is predominant). In CTX neurones where both type I and II variants are expressed, the augmentation ratio of the GABA response by diazepam was between the values in CPJ and SVH neurones. 4. In concentration-response relationships of BZR partial agonists, the threshold concentrations, KD values and maximal augmentation ratio of the GABA response were similar in all CTX, CPJ and SVH neurones. Also, in all preparations, the threshold concentration and KD values of diazepam action were 10 fold less than those induced by partial agonists. 5. All BZR agonists shifted the concentration-response relationship for GABA to the left without changing the maximum current amplitude, indicating that activation of both BZ1 and BZ2 increase the affinity of the GABAA receptor for GABA.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8395299

  4. Differential properties of type I and type II benzodiazepine receptors in mammalian CNS neurones.

    PubMed

    Yakushiji, T; Shirasaki, T; Munakata, M; Hirata, A; Akaike, N

    1993-07-01

    1. The effects of benzodiazepine receptor (BZR) partial agonists, Y-23684 and CL218,872, were compared with its full agonist, diazepam, on gamma-aminobutyric acid (GABA)-induced Cl- current (ICl) in acutely dissociated rat cerebral cortex (CTX), cerebellar Purkinje (CPJ) and spinal ventral horn (SVH) neurones, by the whole-cell mode patch-clamp technique. 2. The GABA-induced responses were essentially the same in both SVH and CPJ neurones, but the KD value of the GABA response in CTX neurone was lower than those in the other two brain regions. 3. Enhancement of the GABA response by the two partial agonists was about one-third of that by diazepam in the SVH neurones (where type II subtype of BZR, BZ2, is predominant), whereas these partial agonists potentiated the GABA response as much as diazepam in CPJ neurones (where the type I subtype of BZR, BZ1, is predominant). In CTX neurones where both type I and II variants are expressed, the augmentation ratio of the GABA response by diazepam was between the values in CPJ and SVH neurones. 4. In concentration-response relationships of BZR partial agonists, the threshold concentrations, KD values and maximal augmentation ratio of the GABA response were similar in all CTX, CPJ and SVH neurones. Also, in all preparations, the threshold concentration and KD values of diazepam action were 10 fold less than those induced by partial agonists. 5. All BZR agonists shifted the concentration-response relationship for GABA to the left without changing the maximum current amplitude, indicating that activation of both BZ1 and BZ2 increase the affinity of the GABAA receptor for GABA. 6. The results are important in clarifying the mechanism of anxiety and might explain the anxioselectivity of BZR partial agonists.

  5. New Hippocampal Neurons Mature Rapidly in Response to Ketamine But Are Not Required for Its Acute Antidepressant Effects on Neophagia in Rats.

    PubMed

    Soumier, Amelie; Carter, Rayna M; Schoenfeld, Timothy J; Cameron, Heather A

    2016-01-01

    Virtually all antidepressant agents increase the birth of granule neurons in the adult dentate gyrus in rodents, providing a key basis for the neurogenesis hypothesis of antidepressant action. The novel antidepressant ketamine, however, shows antidepressant activity in humans within hours, far too rapid for a mechanism involving neuronal birth. Ketamine could potentially act more rapidly by enhancing maturation of new neurons born weeks earlier. To test this possibility, we assessed the effects of S-ketamine (S-(+)-ketamine hydrochloride) injection on maturation, as well as birth and survival, of new dentate gyrus granule neurons in rats, using the immediate-early gene zif268, proliferating cell nuclear antigen, and BrdU, respectively. We show that S-ketamine has rapid effects on new neurons, increasing the proportion of functionally mature young granule neurons within 2 h. A single injection of S-ketamine also increased cell proliferation and functional maturation, and decreased depressive-like behavior, for at least 4 weeks in rats treated with long-term corticosterone administration (a depression model) and controls. However, the behavioral effects of S-ketamine on neophagia were unaffected by elimination of adult neurogenesis. Together, these results indicate that ketamine has surprisingly rapid and long-lasting effects on the recruitment of young neurons into hippocampal networks, but that ketamine has antidepressant-like effects that are independent of adult neurogenesis.

  6. New Hippocampal Neurons Mature Rapidly in Response to Ketamine But Are Not Required for Its Acute Antidepressant Effects on Neophagia in Rats123

    PubMed Central

    Soumier, Amelie; Carter, Rayna M.; Schoenfeld, Timothy J.

    2016-01-01

    Abstract Virtually all antidepressant agents increase the birth of granule neurons in the adult dentate gyrus in rodents, providing a key basis for the neurogenesis hypothesis of antidepressant action. The novel antidepressant ketamine, however, shows antidepressant activity in humans within hours, far too rapid for a mechanism involving neuronal birth. Ketamine could potentially act more rapidly by enhancing maturation of new neurons born weeks earlier. To test this possibility, we assessed the effects of S-ketamine (S-(+)-ketamine hydrochloride) injection on maturation, as well as birth and survival, of new dentate gyrus granule neurons in rats, using the immediate-early gene zif268, proliferating cell nuclear antigen, and BrdU, respectively. We show that S-ketamine has rapid effects on new neurons, increasing the proportion of functionally mature young granule neurons within 2 h. A single injection of S-ketamine also increased cell proliferation and functional maturation, and decreased depressive-like behavior, for at least 4 weeks in rats treated with long-term corticosterone administration (a depression model) and controls. However, the behavioral effects of S-ketamine on neophagia were unaffected by elimination of adult neurogenesis. Together, these results indicate that ketamine has surprisingly rapid and long-lasting effects on the recruitment of young neurons into hippocampal networks, but that ketamine has antidepressant-like effects that are independent of adult neurogenesis. PMID:27066531

  7. Shock induced dissociation of polyethylene

    SciTech Connect

    Morris, C.E.; Loughran, E.D.; Mortensen, G.F.; Gray, G.T. III; Shaw, M.S.

    1989-01-01

    To identify the physical processes occurring on the Hugoniot, shock-recovery experiments were performed. Cylindrical recovery systems were used that enabled a wide range of single-shock Hugoniot states to be examined. Mass spectroscopy was used to examine the gaseous dissociation products. X-ray and TEM measurements were made to characterize the post-shock carbon structures. A dissociation product equation of state is presented to interpret the observed results. Polyethylene (PE) samples that were multiply shocked to their final states dissociated at much higher pressures than single-shocked samples. 5 refs., 2 figs., 1 tab.

  8. Are major dissociative disorders characterized by a qualitatively different kind of dissociation?

    PubMed

    Rodewald, Frauke; Dell, Paul F; Wilhelm-Gossling, Claudia; Gast, Ursula

    2011-01-01

    A total of 66 patients with a major dissociative disorder, 54 patients with nondissociative disorders, and 30 nonclinical controls were administered the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised, the Dissociative Experiences Scale, the Multidimensional Inventory of Dissociation, and the Symptom Checklist 90-Revised. Dissociative patients reported significantly more dissociative and nondissociative symptoms than did nondissociative patients and nonclinical controls. When general psychopathology was controlled, the dissociation scores of dissociative patients were still significantly higher than those of both other groups, whereas the dissociation scores of nondissociative patients and nonclinical controls no longer differed. These findings appear to be congruent with a typological model of dissociation that distinguishes between 2 qualitatively different kinds of dissociation. Specifically, the results of this study suggest that the dissociation that occurs in major dissociative disorders (i.e., dissociative identity disorder [DID] and dissociative disorder not otherwise specified, Type 1 [DDNOS-1]) is qualitatively different from the dissociation that occurs in persons who do not have a dissociative disorder. In contrast to previous research, the dissociation of persons who do not have a dissociative disorder is not limited to absorption; it covers a much wider range of phenomena. The authors hypothesize that different mechanisms produce the dissociation of persons with DID and DDNOS-1 as opposed to the dissociation of persons who do not have a dissociative disorder.

  9. Antibody uptake into neurons occurs primarily via clathrin-dependent Fcγ receptor endocytosis and is a prerequisite for acute tau protein clearance.

    PubMed

    Congdon, Erin E; Gu, Jiaping; Sait, Hameetha B R; Sigurdsson, Einar M

    2013-12-06

    Tau immunotherapy is effective in transgenic mice, but the mechanisms of Tau clearance are not well known. To this end, Tau antibody uptake was analyzed in brain slice cultures and primary neurons. Internalization was rapid (<1 h), saturable, and substantial compared with control mouse IgG. Furthermore, temperature reduction to 4 °C, an excess of unlabeled mouse IgG, or an excess of Tau antibodies reduced uptake in slices by 63, 41, and 62%, respectively (p = 0.002, 0.04, and 0.005). Uptake strongly correlated with total and insoluble Tau levels (r(2) = 0.77 and 0.87 and p = 0.002 and 0.0002), suggesting that Tau aggregates influence antibody internalization and/or retention within neurons. Inhibiting phagocytosis did not reduce uptake in slices or neuronal cultures, indicating limited microglial involvement. In contrast, clathrin-specific inhibitors reduced uptake in neurons (≤ 78%, p < 0.0001) and slices (≤ 35%, p = 0.03), demonstrating receptor-mediated endocytosis as the primary uptake pathway. Fluid phase endocytosis accounted for the remainder of antibody uptake in primary neurons, based on co-staining with internalized dextran. The receptor-mediated uptake is to a large extent via low affinity FcγII/III receptors and can be blocked in slices (43%, p = 0.04) and neurons (53%, p = 0.008) with an antibody against these receptors. Importantly, antibody internalization appears to be necessary for Tau reduction in primary neurons. Overall, these findings clarify that Tau antibody uptake is primarily receptor-mediated, that these antibodies are mainly found in neurons with Tau aggregates, and that their intracellular interaction leads to clearance of Tau pathology, all of which have major implications for therapeutic development of this approach.

  10. Recurrent Episodes of Dissociative Fugue

    PubMed Central

    Angothu, Hareesh; Pabbathi, Lokeswar Reddy

    2016-01-01

    Dissociative fugue is rare entity to encounter with possible differentials of epilepsy and malingering. It is one of the dissociative disorders rarely seen in clinical practice more often because of the short lasting nature of this condition. This might also be because of organized travel of the individuals during the episodes and return to their families after the recovery from episodes. This is a case description of a patient who has experienced total three episodes of dissociative fugue. The patient has presented during the third episode and two prior episodes were diagnosed as fugue episodes retrospectively based on the history. Planned travel in this case by the patient to a distant location was prevented because of early diagnosis and constant vigilance till the recovery. As in this case, it may be more likely that persons with Dissociative fugue may develop similar episodes if they encounter exceptional perceived stress. However, such conclusions may require follow-up studies. PMID:27114633

  11. Dissociation Rates of Diatomic Molecules

    DTIC Science & Technology

    1992-12-01

    relatively simple design that we have used extensively in earlier research; its characteristics were recently described in detail. 10 This source is by...the dominant dissociation background when observing electron- impact dissociation products. This background constitutes the single greatest impediment...a3aF) + o(3P) at 11.385 eV. Photoexcitation studies indeed find that O(1S) and CO(a) are the dominant photodissociation products. 32,33 If the energy

  12. Dissociative disorders in DSM-5.

    PubMed

    Spiegel, David; Lewis-Fernández, Roberto; Lanius, Ruth; Vermetten, Eric; Simeon, Daphne; Friedman, Matthew

    2013-01-01

    The rationale, research literature, and proposed changes to the dissociative disorders and conversion disorder in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) are presented. Dissociative identity disorder will include reference to possession as well as identity fragmentation, to make the disorder more applicable to culturally diverse situations. Dissociative amnesia will include dissociative fugue as a subtype, since fugue is a rare disorder that always involves amnesia but does not always include confused wandering or loss of personality identity. Depersonalization disorder will include derealization as well, since the two often co-occur. A dissociative subtype of posttraumatic stress disorder (PTSD), defined by the presence of depersonalization or derealization in addition to other PTSD symptoms, is being recommended, based upon new epidemiological and neuroimaging evidence linking it to an early life history of adversity and a combination of frontal activation and limbic inhibition. Conversion disorder (functional neurological symptom disorder) will likely remain with the somatic symptom disorders, despite considerable dissociative comorbidity.

  13. Taurine activates excitatory non-synaptic glycine receptors on dopamine neurones in ventral tegmental area of young rats.

    PubMed

    Wang, Fushun; Xiao, Cheng; Ye, Jiang Hong

    2005-06-01

    The physiological and pharmacological properties of taurine-induced responses were investigated in dopaminergic (DA) neurones from the ventral tegmental area (VTA) of young rats aged 1-13 postnatal days, either in acute brain slices or acutely dissociated neurones. When whole-cell responses were recorded from current-clamped neurones using the gramicidin-perforated technique, the application of taurine (0.01-30 mm) accelerated firings and induced membrane depolarization. In voltage-clamped neurones, taurine induced a current which was antagonized by strychnine and by picrotoxin, but not by bicuculline. In addition, taurine-induced current showed complete cross-desensitization with glycine-activated currents but not with gamma-aminobutyric acid (GABA)-activated currents. Thus, taurine is a full agonist of the glycine receptors (GlyRs) in the VTA. Further studies found that taurine acted mainly on non-synaptic GlyRs. The application of 20 microm bicuculline abolished the spontaneous inhibitory post-synaptic currents (IPSCs) in 40/45 neurones, and 93% of the evoked IPSCs. The addition of 1 microm strychnine completely eliminated the remaining IPSCs. These results suggest that GABAergic IPSCs predominate, and that functional glycinergic synapses are present in a subset of the VTA neurones. The application of 1 mum strychnine alone induced an outward current, suggesting that these neurones were exposed to tonically released taurine/glycine. In conclusion, by activating non-synaptic GlyRs, taurine may act as an excitatory extra-synaptic neurotransmitter in the VTA during early development.

  14. Global functioning and disability in dissociative disorders.

    PubMed

    Mueller-Pfeiffer, Christoph; Rufibach, Kaspar; Perron, Noelle; Wyss, Daniela; Kuenzler, Cornelia; Prezewowsky, Cornelia; Pitman, Roger K; Rufer, Michael

    2012-12-30

    Dissociative disorders are frequent comorbid conditions of other mental disorders. Yet, there is controversy about their clinical relevance, and little systematic research has been done on how they influence global functioning. Outpatients and day care patients (N=160) of several psychiatric units in Switzerland were assessed with the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV Axis I Disorders, Structured Clinical Interview for DSM-IV Dissociative Disorders, Global Assessment of Functioning Scale, and World Health Organization Disability Assessment Schedule-II. The association between subjects with a dissociative disorder (N=30) and functional impairment after accounting for non-dissociative axis I disorders was evaluated by linear regression models. We found a proportion of 18.8% dissociative disorders (dissociative amnesia=0%, dissociative fugue=0.6%, depersonalization disorder=4.4%, dissociative identity disorder=7.5%, dissociative disorder-not-otherwise-specified=6.3%) across treatment settings. Adjusted for other axis I disorders, subjects with a comorbid dissociative identity disorder or dissociative disorder-not-otherwise-specified had a median global assessment of functioning score that was 0.86 and 0.88 times, respectively, the score of subjects without a comorbid dissociative disorder. These findings support the hypothesis that complex dissociative disorders, i.e., dissociative identity disorder and dissociative disorder-not-otherwise-specified, contribute to functional impairment above and beyond the impact of co-existing non-dissociative axis I disorders, and that they qualify as "serious mental illness".

  15. Cryopreservation of adherent neuronal networks.

    PubMed

    Ma, Wu; O'Shaughnessy, Thomas; Chang, Eddie

    2006-07-31

    Neuronal networks have been widely used for neurophysiology, drug discovery and toxicity testing. An essential prerequisite for future widespread application of neuronal networks is the development of efficient cryopreservation protocols to facilitate their storage and transportation. Here is the first report on cryopreservation of mammalian adherent neuronal networks. Dissociated spinal cord cells were attached to a poly-d-lysine/laminin surface and allowed to form neuronal networks. Adherent neuronal networks were embedded in a thin film of collagen gel and loaded with trehalose prior to transfer to a freezing medium containing DMSO, FBS and culture medium. This was followed by a slow rate of cooling to -80 degrees C for 24 h and then storage for up to 2 months in liquid nitrogen at -196 degrees C. The three components: DMSO, collagen gel entrapment and trehalose loading combined provided the highest post-thaw viability, relative to individual or two component protocols. The post-thaw cells with this protocol demonstrated similar neuronal and astrocytic markers and morphological structure as those detected in unfrozen cells. Fluorescent dye FM1-43 staining revealed active recycling of synaptic vesicles upon depolarizing stimulation in the post-thaw neuronal networks. These results suggest that a combination of DMSO, collagen gel entrapment and trehalose loading can significantly improve conventional slow-cooling methods in cryopreservation of adherent neuronal networks.

  16. Does dissociation further our understanding of PTSD?

    PubMed

    Bryant, Richard A

    2007-01-01

    Peritraumatic dissociation, and other dissociative reactions, refer to alterations in awareness in the context of a traumatic experience. This review provides an overview of the current conceptualization of dissociation, critiques methodological approaches to studying dissociation, and reviews the evidence for the purported relationship between dissociative reactions and posttraumatic stress disorder. The evidence challenges the notion that a linear relationship exists between dissociation and psychiatric morbidity. Future research should abandon the global construct of dissociation, and study the specific responses that involve altered awareness under experimental conditions.

  17. COMMUNICATION: Folate and S-adenosylmethionine modulate synaptic activity in cultured cortical neurons: acute differential impact on normal and apolipoprotein-deficient mice

    NASA Astrophysics Data System (ADS)

    Serra, Michael; Chan, Amy; Dubey, Maya; Gilman, Vladimir; Shea, Thomas B.

    2008-12-01

    Folate deficiency is accompanied by a decline in the cognitive neurotransmitter acetylcholine and a decline in cognitive performance in mice lacking apolipoprotein E (ApoE-/- mice), a low-density lipoprotein that regulates aspects of lipid metabolism. One direct consequence of folate deficiency is a decline in S-adenosylmethionine (SAM). Since dietary SAM supplementation maintains acetylcholine levels and cognitive performance in the absence of folate, we examined herein the impact of folate and SAM on neuronal synaptic activity. Embryonic cortical neurons from mice expressing or lacking ApoE (ApoE+/+ or -/-, respectively) were cultured for 1 month on multi-electrode arrays, and signaling was recorded. ApoE+/+ cultures displayed significantly more frequent spontaneous signals than ApoE-/- cultures. Supplementation with 166 µm SAM (not normally present in culture medium) increased signal frequency and decreased signal amplitude in ApoE+/+ cultures. SAM also increased the frequency of tightly clustered signal bursts. Folate deprivation reversibly reduced signal frequency in ApoE+/+ cultures; SAM supplementation maintained signal frequency despite folate deprivation. These findings support the importance of dietary supplementation with folate and SAM on neuronal health. Supplementation with 166 µm SAM did not alter signaling in ApoE-/- cultures, which may be a reflection of the reduced SAM levels in ApoE-/- mice. The differential impact of SAM on ApoE+/+ and -/- neurons underscores the combined impact of nutritional and genetic deficiencies on neuronal homeostasis.

  18. Involuntariness in hypnotic responding and dissociative symptoms.

    PubMed

    Dell, Paul F

    2010-01-01

    Clark Hull's (1933) research on dissociation was based on a 'straw man' formulation of dissociation; he claimed that dissociation requires noninterference. Hull completely ignored the then-current paradigm of dissociation--dissociation as automatism--and claimed that he had refuted the validity of the phenomenon of dissociation. Hull's view of dissociation held sway in the hypnosis field for 60 years. This essay seeks to retrieve the Janetian paradigm of dissociation as automatism. Automatisms are unexpected, uninitiated, involuntary behaviors that just 'happen.' The author argues that human sensitivity to the experience of involuntariness (a) is quite important, (b) was selected by evolution, and (c) is central to both hypnotic responses and dissociative symptoms. This editorial urges the hypnosis field and the dissociation field to jointly undertake a renewed investigation of the experience of involuntariness and to follow recent neuroimaging studies which indicate that the parietal cortex underlies the experience of involuntariness.

  19. Low predictive power of peritraumatic dissociation for PTSD symptoms in accident survivors.

    PubMed

    Wittmann, Lutz; Moergeli, Hanspeter; Schnyder, Ulrich

    2006-10-01

    To test the predictive power of peritraumatic dissociation for the development of psychopathology, the authors assessed symptoms of peritraumatic dissociation (Peritraumatic Dissociative Experiences Questionnaire; PDEQ), posttraumatic stress disorder (Clinician-Administered PTSD Scale; CAPS), anxiety and depression (Hospital Anxiety and Depression Scale; HADS) in a sample of 214 accident victims 5 days postaccident (T1). Six months later (T2), CAPS and HADS were administered again. Acute stress disorder (ASD) and PTSD symptom levels were surprisingly low. In sequential regression analyses, initial reexperiencing and hyperarousal significantly predicted PTSD symptom level (T2) over several possibly confounding variables controlled for. Peritraumatic dissociation explained less than 3% of variance. For PTSD scores, 38% overall variance explanation was obtained; the variance for HADS scores was low. Possible explanations for the low-predictive power of peritraumatic dissociation for posttraumatic psychopathology in the sample are discussed.

  20. Dissociative disorders among alcohol-dependent inpatients.

    PubMed

    Evren, Cuneyt; Sar, Vedat; Karadag, Figen; Tamar Gurol, Defne; Karagoz, Mustafa

    2007-08-30

    The aim of this study was to determine the prevalence of dissociative disorders among inpatients with alcohol dependency. The Dissociative Experiences Scale was used to screen 111 alcohol-dependent patients consecutively admitted to the inpatient unit of a dependency treatment center. Subgroups of 29 patients who scored 30.0 or above and 25 patients who scored below 10.0 were then evaluated with the Dissociative Disorders Interview Schedule and the Structured Interview for DSM-IV Dissociative Disorders. The interviewers were blind to the Dissociative Experiences Scale scores. Of the 54 patients evaluated, 10 (9.0% of the original 111) patients had a dissociative disorder. A considerable number of the remaining patients reported a high level of dissociative experiences. Among the dissociative disorder group, nine patients had dissociative disorder not otherwise specified and one patient had depersonalization disorder. Female gender, younger age, history of suicide attempt, childhood emotional and sexual abuse, and neglect were more frequent in the dissociative disorder group than among non-dissociative patients. The dissociative disorder group also had somatization disorder, borderline personality disorder, and lifetime major depression more frequently. For 9 of the 10 dissociative patients, dissociative symptoms started before the onset of alcohol use. Although the probability of having a comorbid dissociative disorder was not higher among alcohol-dependent inpatients than among the general psychiatric inpatients, the dissociative subgroup had distinct features. Many patients without a dissociative disorder diagnosis (predominantly men) provided hints of subtle dissociative psychopathology. Implications of comorbid dissociative disorders and dissociative experiences on prevention and treatment of alcohol dependency and the importance of gender-specific characteristics in this relationship require further study.

  1. Peritraumatic dissociation and posttraumatic stress after pregnancy loss: a prospective study.

    PubMed

    Engelhard, Iris M; van den Hout, Marcel A; Kindt, Merel; Arntz, Arnoud; Schouten, Erik

    2003-01-01

    This study examined (1). predictors for peritraumatic dissociation, (2). its relations with acute and chronic symptoms of posttraumatic stress disorder (PTSD), and (3). pathways regarding these relations in response to pregnancy loss. In early pregnancy, about 1370 women volunteers completed questionnaires for neuroticism, control over emotions, dissociative tendencies, absorption, and prior life events. Of these, 126 subsequently experienced pregnancy loss and most of them completed measures 1 month (N = 118) and 4 months (N = 104) later. At 1 month, peritraumatic dissociation, memory of pregnancy loss (degree of fragmentation, sensory impressions, and emotional intensity), thought suppression, and PTSD symptoms were assessed, and at 4 months, PTSD symptoms were re-assessed. Peritraumatic dissociation was predicted by prior low control over emotions, dissociative tendencies, and lower education. It was not predicted by neuroticism, absorption, and prior life events. Peritraumatic dissociation was related to acute PTSD symptoms and LISREL analyses indicated that self-reported memory fragmentation and thought suppression of pregnancy loss mediated this relation. It also predicted chronic PTSD symptoms, and this relation was mediated by acute PTSD symptoms.

  2. Dissociative symptomatology in cancer patients

    PubMed Central

    Civilotti, Cristina; Castelli, Lorys; Binaschi, Luca; Cussino, Martina; Tesio, Valentina; Di Fini, Giulia; Veglia, Fabio; Torta, Riccardo

    2015-01-01

    Introduction: The utilization of the post-traumatic stress disorder (PTSD) diagnostic spectrum is currently being debated to categorize psychological adjustment in cancer patients. The aims of this study were to: (1) evaluate the presence of cancer-related traumatic dissociative symptomatology in a sample of cancer patients; (2) examine the correlation of cancer-related dissociation and sociodemographic and medical variables, anxiety, depression, and post-traumatic stress symptomatology; (3) investigate the predictors of cancer-related dissociation. Methods: Ninety-two mixed cancer patients (mean age: 58.94, ds = 10.13) recruited from two hospitals in northern Italy were administered a questionnaire on sociodemographic and medical characteristics, the Karnofsky Scale to measure the level of patient activity and medical care requirements, the Hospital Anxiety and Depression Scale (HADS) to evaluate the presence of anxiety and depression, the Impact of Event Scale Revised (IES-R) to assess the severity of intrusion, avoidance, and hypervigilance, and the Peritraumatic Dissociative Experiences Questionnaire (PDEQ) to quantify the traumatic dissociative symptomatology. Results: 31.5% of participants report a PDEQ score above the cutoff. The results indicated that dissociative symptomatology was positively correlated with HADS scores (HADS-Anxiety: r = 0.476, p < 0.001; HADS-Depression: r = 0.364, p < 0.001) and with IES-R scores (IES-R-Intrusion: r = 0.698, p < 0.001; IES-R-Avoidance: r = 0.619, p < 0.001; IES-R- Hypervigilance: r = 0.681, p < 0.001). A stepwise regression analysis was performed in order to find the predictors of cancer-related traumatic dissociative symptomatology. The results converged on a three predictor model revealing that IES-R-Intrusion, IES-R-Avoidance, and IES-R-Hyperarousal accounted for 53.9% of the explained variance. Conclusion: These findings allow us to hypothesize a specific psychological reaction which may be ascribed to the traumatic

  3. Dissociative Electron Attachment to chloroacetylene

    NASA Astrophysics Data System (ADS)

    Ngassam, V.; Orel, A. E.

    2007-06-01

    The production of two fragments with σ symmetry from electron-impact dissociation of C2H2, which has only a low lying &*circ; resonance at equilibrium geometry, has been explained by the existence of interactions with &*circ; resonances at bent geometries. We are investigating the presence of such multidimensional effects in the dissociative attachment of chloroacetylene (C2HCl). We have performed electron scattering calculations using the Complex Kohn variational method to determine the resonance energies and widths of the chloroacetylene resonances as a function of both the Cl--C2H bond distance as well as the variation with C-C stretch and bend. We will discuss our results and our prediction of the dissociation dynamics in comparison to the findings for for C2H2. This work was supported by the U.S. DOE Office of Basic Energy Sciences, Division of Chemical Sciences and the National Science Foundation, PHY-05-55401.

  4. Diffraction dissociation at the LHC

    SciTech Connect

    Jenkovszky, Laszlo; Orava, Risto; Salii, Andrii

    2013-04-15

    We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

  5. [Dissociative identity disorder or schizophrenia?].

    PubMed

    Tschöke, S; Steinert, T

    2010-01-01

    We present a case of dissociative identity disorder in which Schneiderian first rank symptoms were present besides of various states of consciousness. Thus the diagnosis of schizophrenia had to be considered. Formally, the symptoms met ICD-10 criteria for schizophrenia. However, taking into account the lack of formal thought disorder and of negative symptoms as well as a typical history of severe and prolonged traumatisation, we did not diagnose a co-morbid schizophrenic disorder. There is good evidence for the existence of psychotic symptoms among patients with dissociative disorders. However, in clinical practice this differential diagnosis is rarely considered.

  6. [Gender differences in dissociative disorders].

    PubMed

    Spitzer, C; Freyberger, H J

    2008-01-01

    The relationship between mental illness, on the one hand, and sex and gender, on the other hand, has received interest since the beginning of medicine in antique times. A prototypical example of a seemingly woman-specific disease is hysteria. The term itself, which is derived from the Greek word for womb, denotes a psychosexual dimension comprising the current attitude towards sexuality and the dominating gender relationship. In addition, the colourful history of hysteria indicates that illness is not exclusively determined by biological factors, but also significantly by socio-cultural influences, for example in the treatment of hysterical women. Even nowadays, there is a wide-spread belief that dissociative symptoms and disorders, which have succeeded hysteria in current classification systems, are predominantly seen in women. However, empirical studies in the general population and in different clinical samples using sound instruments have indicated that dissociative symptoms do not differ between the genders. The seemingly dominance of dissociative disorders in women may also depend on the socio-cultural context, because men with dissociative disorders usually do not enter the general health system, but rather the legal system, i.e. they can be found in jail or forensic institutions.

  7. Super-dissociative recombination of H2+?

    NASA Astrophysics Data System (ADS)

    Mitchell, J. B. A.; Yousif, F. B.; van der Donk, P. J. T.; Morgan, T. J.; Chibisov, M. I.

    1995-11-01

    The dissociative recombination of vibrationally excited H2+ ions to form products in high Rydberg states has been measured. Surprisingly large cross-sections are found for this channel. This seems to be an example of super-dissociative recombination.

  8. Aberrant CpG Methylation Mediates Abnormal Transcription of MAO-A Induced by Acute and Chronic L-3,4-Dihydroxyphenylalanine Administration in SH-SY5Y Neuronal Cells.

    PubMed

    Yang, Zhaofei; Wang, Xuan; Yang, Jian; Sun, Min; Wang, Yong; Wang, Xiaomin

    2017-04-01

    L-3,4-dihydroxyphenylalanine (L-dopa) remains the most effective drug for therapy of Parkinson's disease (PD); however, long-term use of it causes serious side effects. L-dopa-induced dyskinesia (LID) has consistently been related to L-dopa-derived excessive dopamine release, but the mechanisms have not been addressed very clear. Monoamine oxidase A (MAO-A) is one of the key enzymes in dopamine metabolism and therefore may be involved in L-dopa-induced side effects. And, epigenetic modification controls MAO-A gene transcription. To investigate the effects of L-dopa on MAO-A transcription and its underlying epigenetic mechanism, neuronal SH-SY5Y cells were treated with L-dopa for 24 h (acute) and for 7-21 days (chronic). Results showed that chronic L-dopa administration resulted in a dose-dependent and time-dependent downregulation of MAO-A, whereas acute L-dopa administration induced upregulation of MAO-A transcription and expression. Meanwhile, chronic L-dopa exposure induced CpG hypermethylation in MAO-A promoter, while acute L-dopa administration caused CpG hypomethylation. And, CpG demethylation resulted in reactivation of MAO-A transcription. These results indicated that aberrant CpG methylation might play a key role in MAO-A transcriptional misregulation in L-dopa administration. In addition, results showed that acute L-dopa administration induced downregulation of DNA methyltransferase 3a (DNMT3a). Transcription of ten-eleven translocation 1 (TET1) were significantly downregulated in chronic L-dopa administration. These data indicated that in chronic L-dopa administration, TET1 downregulation might mediate CpG hypermethylation, which is responsible for the downregulation of MAO-A transcription. In contrast, in acute L-dopa administration, DNMT3a downregulation might mediate hypomethylation, contributing to the MAO-A upregulation. In conclusion, our findings suggested that TET1 and DNMTs might mediate aberrant CpG methylation, associated with the

  9. A-Kinase Anchoring Protein 79/150 Coordinates Metabotropic Glutamate Receptor Sensitization of Peripheral Sensory Neurons

    PubMed Central

    Szteyn, Kalina; Rowan, Matthew P.; Gomez, Ruben; Du, Junhui; Carlton, Susan M.; Jeske, Nathaniel A.

    2016-01-01

    Glutamate serves as the primary excitatory neurotransmitter in the nervous system. Previous studies have identified a role for glutamate and group I metabotropic receptors as targets for study in peripheral inflammatory pain. However, the coordination of signaling events that transpire from receptor activation to afferent neuronal sensitization has not been explored. Herein, we identify that scaffolding protein A-Kinase Anchoring Protein 79/150 (AKAP150) coordinates increased peripheral thermal sensitivity following group I metabotropic receptor (mGluR5) activation. In both acute and persistent models of thermal somatosensory behavior, we report that mGluR5 sensitization requires AKAP150 expression. Furthermore, electrophysiological approaches designed to record afferent neuronal activity reveal that mGluR5 sensitization also requires functional AKAP150 expression. In dissociated primary afferent neurons, mGluR5 activation increases TRPV1 responses in an AKAP dependent manner through a mechanism that induces AKAP association with TRPV1. Experimental results presented herein identify a mechanism of receptor-driven scaffolding association with ion channel targets. Importantly, this mechanism could prove significant in the search for therapeutic targets that repress episodes of acute pain from becoming chronic in nature. PMID:26172554

  10. Network synchronization in hippocampal neurons.

    PubMed

    Penn, Yaron; Segal, Menahem; Moses, Elisha

    2016-03-22

    Oscillatory activity is widespread in dynamic neuronal networks. The main paradigm for the origin of periodicity consists of specialized pacemaking elements that synchronize and drive the rest of the network; however, other models exist. Here, we studied the spontaneous emergence of synchronized periodic bursting in a network of cultured dissociated neurons from rat hippocampus and cortex. Surprisingly, about 60% of all active neurons were self-sustained oscillators when disconnected, each with its own natural frequency. The individual neuron's tendency to oscillate and the corresponding oscillation frequency are controlled by its excitability. The single neuron intrinsic oscillations were blocked by riluzole, and are thus dependent on persistent sodium leak currents. Upon a gradual retrieval of connectivity, the synchrony evolves: Loose synchrony appears already at weak connectivity, with the oscillators converging to one common oscillation frequency, yet shifted in phase across the population. Further strengthening of the connectivity causes a reduction in the mean phase shifts until zero-lag is achieved, manifested by synchronous periodic network bursts. Interestingly, the frequency of network bursting matches the average of the intrinsic frequencies. Overall, the network behaves like other universal systems, where order emerges spontaneously by entrainment of independent rhythmic units. Although simplified with respect to circuitry in the brain, our results attribute a basic functional role for intrinsic single neuron excitability mechanisms in driving the network's activity and dynamics, contributing to our understanding of developing neural circuits.

  11. Dissociative Mothers' Subjective Experience of Parenting.

    ERIC Educational Resources Information Center

    Benjamin, Lynn R.; And Others

    1996-01-01

    A study of 54 mothers with a dissociative disorder, 20 mothers with other mental problems, and 20 normal mothers investigated what effect, if any, dissociation had on parenting. When tested on the Subjective Experiences of Parenting Scale, mothers with dissociation presented significantly more negative parenting behavior and attitudes. (CR)

  12. Misattributing the Source of Self-Generated Representations Related to Dissociative and Psychotic Symptoms

    PubMed Central

    Chiu, Chui-De; Tseng, Mei-Chih Meg; Chien, Yi-Ling; Liao, Shih-Cheng; Liu, Chih-Min; Yeh, Yei-Yu; Hwu, Hai-Gwo

    2016-01-01

    Objective: An intertwined relationship has been found between dissociative and psychotic symptoms, as the two symptom clusters frequently co-occur, suggesting some shared risk factors. Using a source monitoring paradigm, previous studies have shown that patients with schizophrenia made more errors in source monitoring, suggesting that a weakened sense of individuality may be associated with psychotic symptoms. However, no studies have verified a relationship between sense of individuality and dissociation, and it is unclear whether an altered sense of individuality is a shared sociocognitive deficit underlying both dissociation and psychosis. Method: Data from 80 acute psychiatric patients with unspecified mental disorders were analyzed to test the hypothesis that an altered sense of individuality underlies dissociation and psychosis. Behavioral tasks, including tests of intelligence and source monitoring, as well as interview schedules and self-report measures of dissociative and psychotic symptoms, general psychopathology, and trauma history, were administered. Results: Significant correlations of medium effect sizes indicated an association between errors attributing the source of self-generated items and positive psychotic symptoms and the absorption and amnesia measures of dissociation. The associations with dissociative measures remained significant after the effects of intelligence, general psychopathology, and trauma history were excluded. Moreover, the relationships between source misattribution and dissociative measures remained marginally significant and significant after controlling for positive and negative psychotic symptoms, respectively. Limitations: Self-reported measures were collected from a small sample, and most of the participants were receiving medications when tested, which may have influenced their cognitive performance. Conclusions: A tendency to misidentify the source of self-generated items characterized both dissociation and psychosis

  13. Identifying Candidate Genes that Underlie Cellular pH Sensitivity in Serotonin Neurons Using Transcriptomics: A Potential Role for Kir5.1 Channels

    PubMed Central

    Puissant, Madeleine M.; Mouradian, Gary C.; Liu, Pengyuan; Hodges, Matthew R.

    2017-01-01

    Ventilation is continuously adjusted by a neural network to maintain blood gases and pH. Acute CO2 and/or pH regulation requires neural feedback from brainstem cells that encode CO2/pH to modulate ventilation, including but not limited to brainstem serotonin (5-HT) neurons. Brainstem 5-HT neurons modulate ventilation and are stimulated by hypercapnic acidosis, the sensitivity of which increases with increasing postnatal age. The proper function of brainstem 5-HT neurons, particularly during post-natal development is critical given that multiple abnormalities in the 5-HT system have been identified in victims of Sudden Infant Death Syndrome. Here, we tested the hypothesis that there are age-dependent increases in expression of pH-sensitive ion channels in brainstem 5-HT neurons, which may underlie their cellular CO2/pH sensitivity. Midline raphe neurons were acutely dissociated from neonatal and mature transgenic SSePet-eGFP rats [which have enhanced green fluorescent protein (eGFP) expression in all 5-HT neurons] and sorted with fluorescence-activated cell sorting (FACS) into 5-HT-enriched and non-5-HT cell pools for subsequent RNA extraction, cDNA library preparation and RNA sequencing. Overlapping differential expression analyses pointed to age-dependent shifts in multiple ion channels, including but not limited to the pH-sensitive potassium ion (K+) channel genes kcnj10 (Kir4.1), kcnj16 (Kir5.1), kcnk1 (TWIK-1), kcnk3 (TASK-1) and kcnk9 (TASK-3). Intracellular contents isolated from single adult eGFP+ 5-HT neurons confirmed gene expression of Kir4.1, Kir5.1 and other K+ channels, but also showed heterogeneity in the expression of multiple genes. 5-HT neuron-enriched cell pools from selected post-natal ages showed increases in Kir4.1, Kir5.1, and TWIK-1, fitting with age-dependent increases in Kir4.1 and Kir5.1 protein expression in raphe tissue samples. Immunofluorescence imaging confirmed Kir5.1 protein was co-localized to brainstem neurons and glia including 5

  14. Radiative capture versus Coulomb dissociation.

    SciTech Connect

    Esbensen, H.; Physics

    2006-01-01

    Measurements of the Coulomb dissociation of {sup 8}B have been used to infer the rate of the inverse radiative proton capture on {sup 7}Be. The analysis is usually based on the assumptions that the two processes are related by detailed balance and described by E1 transitions. However, there are corrections to this relation. The Coulomb form factors for the two processes, for example, are not identical. There are also E2 transitions and higher-order effects in the Coulomb dissociation, and the nuclear induced breakup cannot always be ignored. While adding first-order E2 transitions enhances the decay energy spectrum, the other mechanisms cause a suppression at low relative energies. The net result may accidentally be close to the conventional first-order E1 calculation, but there are differences which cannot be ignored if accuracies of 10% or better are needed.

  15. Relationships among childhood trauma, posttraumatic stress disorder, and dissociation in men living with HIV/AIDS.

    PubMed

    Kamen, Charles; Bergstrom, Jessica; Koopman, Cheryl; Lee, Susanne; Gore-Felton, Cheryl

    2012-01-01

    This study examined the relationships among dissociation, childhood trauma and sexual abuse, and posttraumatic stress disorder (PTSD) symptoms in HIV-positive men. Data were collected from 167 men enrolled in a randomized clinical trial that examined a group therapy intervention to decrease HIV-related risk behavior and trauma-related stress symptoms. Participants completed the Trauma History Questionnaire, the Impact of Events Scale-Revised, and the Stanford Acute Stress Reaction Questionnaire. Overall, 35.3% of the participants reported having experienced childhood sexual abuse. A total of 55.7% of the sample met diagnostic criteria for PTSD. The intensity of dissociative symptoms that participants endorsed was positively associated with experience of childhood sexual abuse (r = .20, p < .01). Dissociative symptoms were also positively associated with specific PTSD symptoms, notably hyperarousal (r = .69, p < .001). Hierarchical regression indicated that hyperarousal symptoms accounted for more of the variance in dissociation than childhood sexual abuse. These results suggest that childhood sexual abuse may be involved in the development of dissociative symptoms in the context of adulthood stress reactions. Furthermore, the pattern of the association between dissociation and PTSD is consistent with the possibility of a dissociative PTSD subtype among HIV-positive men.

  16. Thermal Dissociation of Halogen Azides

    DTIC Science & Technology

    1994-09-01

    inefficient due to the low gain provided by this emitter and the short duration of the shock tube experiment . Much higher gain coefficients were...with the SF6 sensitizers (in the C02 laser triggered experiment ) and thermal dissociation of the tetraazldodiborane donor ;nto non-productive...Excitation of FN3/S2CI 2/SF6 gas mixtures by the pulsed C02 laser yielded NS(B-X) chemiluminescence 5 . Cold trap experiments showed that small levels

  17. [Differential diagnosis between dissociative disorders and schizophrenia].

    PubMed

    Shibayama, Masatoshi

    2011-01-01

    The differential diagnosis of dissociative disorders includes many psychiatric disorders, such as schizophrenia, bipolar disorders (especially bipolar II disorder), depressive disorder (especially atypical depression), epilepsy, Asperger syndrome, and borderline personality disorder. The theme of this paper is the differential diagnosis between dissociative disorders and schizophrenia. Schneiderian first-rank symptoms in schizophrenia are common in dissociative disorders, especially in dissociative identity disorder (DID). Many DID patients have been misdiagnosed as schizophrenics and treated with neuroleptics. We compared and examined Schneiderian symptoms of schizophrenia and those of dissociative disorders from a structural viewpoint. In dissociative disorders, delusional perception and somatic passivity are not seen. "Lateness" and "Precedence of the Other" originated from the concept of "Pattern Reversal" (H. Yasunaga)" is characteristic of schizophrenia. It is important to check these basic structure of schizophrenia in subjective experiences in differential diagnosis between dissociative disorders and schizophrenia.

  18. Acute genetic manipulation of neuronal activity for the functional dissection of neural circuits-a dream come true for the pioneers of behavioral genetics.

    PubMed

    Yoshihara, Moto; Ito, Kei

    2012-03-01

    Abstract: This review summarizes technical development of the functional manipulation of specific neural circuits through genetic techniques in Drosophila. Long after pioneers' efforts for the genetic dissection of behavior using this organism as a model, analyses with acute activation of specific neural circuits have finally become feasible using transgenic Drosophila that expresses light-, heat-, or cold-activatable cation channels by xxx/upstream activation sequence (Gal4/UAS)-based induction system. This methodology opened a new avenue to dissect functions of neural circuits to make dreams of the pioneers into reality.

  19. Acute response of hypophysiotropic thyrotropin releasing hormone neurons and thyrotropin release to behavioral paradigms producing varying intensities of stress and physical activity.

    PubMed

    Gutiérrez-Mariscal, Mariana; Sánchez, Edith; García-Vázquez, Arlene; Rebolledo-Solleiro, Daniela; Charli, Jean-Louis; Joseph-Bravo, Patricia

    2012-11-10

    The activity of the hypothalamus-pituitary-thyroid (HPT) axis is essential for energy homeostasis and is differentially modulated by physical and by psychological stress. Contradictory effects of stressful behavioral paradigms on TSH or thyroid hormone release are due to type, length and controllability of the stressor. We hypothesized that an additional determinant of the activity of the HPT axis is the energy demand due to physical activity. We thus evaluated the response of thyrotropin releasing hormone (TRH) neurons of the hypothalamic paraventricular nucleus (PVN) in Wistar male rats submitted to the elevated plus maze (EPM), the open field test (OFT), or restraint, and sacrificed within 1h after test completion; the response to OFT was compared during light (L) or dark (D) phases. Locomotion and anxiety behaviors were similar if animals were tested in L or D phases but their relation to the biochemical parameters differed. All paradigms increased serum corticosterone concentration; the levels of corticotropin releasing hormone receptor 1 and of glucocorticoid receptor (GR) mRNAs in the PVN were enhanced after restraint or OFT-L. Levels of proTRH mRNA increased in the PVN after exposure to EPM-L or OFT-D; serum levels of thyrotropin (TSH) and T(4) only after OFT-D. In contrast, restraint decreased TRH mRNA and serum TSH levels, while it increased TRH content in the mediobasal hypothalamus, implying reduced release. Expression of proTRH in the PVN varied proportionally to the degree of locomotion in OFT-D, while inversely to anxiety in the EPM-L, and to corticosterone in EPM-L and OFT-D. TRH mRNA levels were analyzed by in situ hybridization in the rostral, middle and caudal zones of the PVN in response to OFT-D; they increased in the middle PVN, where most TRH hypophysiotropic neurons reside; levels correlated positively with the velocity attained in the periphery of the OF and negatively, with anxiety. Variations of serum TSH levels correlated positively with

  20. [Clinical Handling of Patients with Dissociative Disorders].

    PubMed

    Okano, Kenichiro

    2015-01-01

    This paper discusses the way informed psychiatrists are expected to handle dissociative patients in clinical situations, with a specific focus on dissociative identity disorders and dissociative fugue. On the initial interview with dissociative patients, information on their history of trauma and any nascent dissociative symptoms in their childhood should be carefully obtained. Their level of stress in their current life should also be assessed in order to understand their symptomatology, as well as to predict their future clinical course. A psychoeducational approach is crucial; it might be helpful to give information on dissociative disorder to these patients as well as their family members in order to promote their adherence to treatment. Regarding the symptomatology of dissociative disorders, detailed symptoms and the general clinical course are presented. It was stressed that dissociative identity disorder and dissociative fugue, the most high-profile dissociative disorders, are essentially different in their etiology and clinical presentation. Dissociative disorders are often confused with and misdiagnosed as psychotic disorders, such as schizophrenia. Other conditions considered in terms of the differential diagnosis include borderline personality disorder as well as temporal lobe epilepsy. Lastly, the therapeutic approach to dissociative identity disorder is discussed. Each dissociative identity should be understood as potentially representing some traumatically stressful event in the past. The therapist should be careful not to excessively promote the creation or elaboration of any dissociative identities. Three stages are proposed in the individual psychotherapeutic process. In the initial stage, a secure environment and stabilization of symptoms should be sought. The second stage consists of aiding the "host" personality to make use of other more adaptive coping skills in their life. The third stage involves coaching as well as continuous awareness of

  1. Partial dissociation in the neural bases of VSTM and imagery in the early visual cortex.

    PubMed

    Saad, Elyana; Wojciechowska, Maria; Silvanto, Juha

    2015-08-01

    Visual short-term memory (VSTM) and visual imagery are believed to involve overlapping neuronal representations in the early visual cortex. While a number of studies have provided evidence for this overlap, at the behavioral level VSTM and imagery are dissociable processes; this begs the question of how their neuronal mechanisms differ. Here we used transcranial magnetic stimulation (TMS) to examine whether the neural bases of imagery and VSTM maintenance are dissociable in the early visual cortex (EVC). We intentionally used a similar task for VSTM and imagery in order to equate their assessment. We hypothesized that any differential effect of TMS on VSTM and imagery would indicate that their neuronal bases differ at the level of EVC. In the "alone" condition, participants were asked to engage either in VSTM or imagery, whereas in the "concurrent" condition, each trial required both VSTM maintenance and imagery simultaneously. A dissociation between VSTM and imagery was observed for reaction times: TMS slowed down responses for VSTM but not for imagery. The impact of TMS on sensitivity did not differ between VSTM and imagery, but did depend on whether the tasks were carried concurrently or alone. This study shows that neural processes associated with VSTM and imagery in the early visual cortex can be partially dissociated.

  2. [Neuronal ageing].

    PubMed

    Piechota, Małgorzata; Sunderland, Piotr

    2014-01-01

    Ageing leads to irreversible alterations in the nervous system, which to various extent impair its functions such as capacity to learn and memory. In old neurons and brain, similarly to what may take place in other cells, there is increased oxidative stress, disturbed energetic homeostasis and metabolism, accumulation of damage in proteins and nucleic acids. Characteristic of old neurons are alterations in plasticity, synaptic transmission, sensitivity to neurotrophic factors and cytoskeletal changes. Some markers of senescence, whose one of them is SA-beta-galactosidase were used to show the process of neuronal ageing both in vitro, and in vivo. Some research suggest that, despite the fact that neurons are postmitotic cells, it is cell cycle proteins which play a certain role in their biology, e.g. differentiation. However, their role in neuronal ageing is not known or explained. Ageing is the serious factor of development of neurodegenerative diseases among others Alzheimer disease.

  3. Acute intracerebral treatment with amyloid-beta (1–42) alters the profile of neuronal oscillations that accompany LTP induction and results in impaired LTP in freely behaving rats

    PubMed Central

    Kalweit, Alexander Nikolai; Yang, Honghong; Colitti-Klausnitzer, Jens; Fülöp, Livia; Bozsó, Zsolt; Penke, Botond; Manahan-Vaughan, Denise

    2015-01-01

    Accumulation of amyloid plaques comprises one of the major hallmarks of Alzheimer’s disease (AD). In rodents, acute treatment with amyloid-beta (Aβ; 1–42) elicits immediate debilitating effects on hippocampal long-term potentiation (LTP). Whereas LTP contributes to synaptic information storage, information is transferred across neurons by means of neuronal oscillations. Furthermore, changes in theta-gamma oscillations, that appear during high-frequency stimulation (HFS) to induce LTP, predict whether successful LTP will occur. Here, we explored if intra-cerebral treatment with Aβ(1–42), that prevents LTP, also results in alterations of hippocampal oscillations that occur during HFS of the perforant path-dentate gyrus synapse in 6-month-old behaving rats. HFS resulted in LTP that lasted for over 24 h. In Aβ-treated animals, LTP was significantly prevented. During HFS, spectral power for oscillations below 100 Hz (δ, θ, α, β and γ) was significantly higher in Aβ-treated animals compared to controls. In addition, the trough-to-peak amplitudes of theta and gamma cycles were higher during HFS in Aβ-treated animals. We also observed a lower amount of envelope-to-signal correlations during HFS in Aβ-treated animals. Overall, the characteristic profile of theta-gamma oscillations that accompany successful LTP induction was disrupted. These data indicate that alterations in network oscillations accompany Aβ-effects on hippocampal LTP. This may comprise an underlying mechanism through which disturbances in synaptic information storage and hippocampus-dependent memory occurs in AD. PMID:25999827

  4. Network synchronization in hippocampal neurons

    PubMed Central

    Penn, Yaron; Segal, Menahem; Moses, Elisha

    2016-01-01

    Oscillatory activity is widespread in dynamic neuronal networks. The main paradigm for the origin of periodicity consists of specialized pacemaking elements that synchronize and drive the rest of the network; however, other models exist. Here, we studied the spontaneous emergence of synchronized periodic bursting in a network of cultured dissociated neurons from rat hippocampus and cortex. Surprisingly, about 60% of all active neurons were self-sustained oscillators when disconnected, each with its own natural frequency. The individual neuron’s tendency to oscillate and the corresponding oscillation frequency are controlled by its excitability. The single neuron intrinsic oscillations were blocked by riluzole, and are thus dependent on persistent sodium leak currents. Upon a gradual retrieval of connectivity, the synchrony evolves: Loose synchrony appears already at weak connectivity, with the oscillators converging to one common oscillation frequency, yet shifted in phase across the population. Further strengthening of the connectivity causes a reduction in the mean phase shifts until zero-lag is achieved, manifested by synchronous periodic network bursts. Interestingly, the frequency of network bursting matches the average of the intrinsic frequencies. Overall, the network behaves like other universal systems, where order emerges spontaneously by entrainment of independent rhythmic units. Although simplified with respect to circuitry in the brain, our results attribute a basic functional role for intrinsic single neuron excitability mechanisms in driving the network’s activity and dynamics, contributing to our understanding of developing neural circuits. PMID:26961000

  5. Modulation of direct pathway striatal projection neurons by muscarinic M₄-type receptors.

    PubMed

    Hernández-Flores, Teresa; Hernández-González, Omar; Pérez-Ramírez, María B; Lara-González, Esther; Arias-García, Mario A; Duhne, Mariana; Pérez-Burgos, Azucena; Prieto, G Aleph; Figueroa, Alejandra; Galarraga, Elvira; Bargas, José

    2015-02-01

    Models of basal ganglia (BG) function posit a dynamic balance between two classes of striatal projection neurons (SPNs): direct pathway neurons (dSPNs) that facilitate movements, and indirect pathway neurons (iSPNs) that repress movement execution. Two main modulatory transmitters regulate the output of these neurons: dopamine (DA) and acetylcholine (ACh). dSPNs express D1-type DA, M1-and M4-type ACh receptors, while iSPNs express D2-type DA and M1-type ACh receptors. Actions of M1-, D1-, and D2-receptors have been extensively reported, but we still ignore most actions of muscarinic M4-type receptors. Here, we used whole-cell recordings in acutely dissociated neurons, pharmacological tools such as mamba-toxins, and BAC D(1 or 2)-eGFP transgenic mice to show that activation of M4-type receptors with bath applied muscarine enhances Ca(2+)-currents through CaV1-channels in dSPNs and not in iSPNs. This action increases excitability of dSPNs after both direct current injection and synaptically driven stimulation. The increases in Ca(2+)-current and excitability were blocked specifically by mamba toxin-3, suggesting mediation via M4-type receptors. M4-receptor activation also increased network activity of dSPNs but not of iSPNs as seen with calcium-imaging techniques. Moreover, actions of D1-type and M4-type receptors may add to produce a larger enhancement of excitability of dSPNs or, paradoxically, oppose each other depending on the order of their activation. Possible implications of these findings are discussed.

  6. Comprehensive comparison of collision induced dissociation and electron transfer dissociation.

    PubMed

    Molina, Henrik; Matthiesen, Rune; Kandasamy, Kumaran; Pandey, Akhilesh

    2008-07-01

    Electron transfer dissociation (ETD) is a recently introduced mass spectrometric technique which has proven to be an excellent tool for the elucidation of labile post-translational modifications such as phosphorylation and O-GlcNAcylation of serine and threonine residues. However, unlike collision induced dissociation (CID), which has been studied for decades, the intricacies of ETD-based fragmentation have not yet been firmly established or systematically addressed. In this analysis, we have systematically compared the CID and ETD fragmentation patterns for the large majority of the peptides that do not contain such labile modifications. Using a standard 48 protein mix, we were able to measure false-positive rates for the experiments and also assess a large number of peptides for a detailed comparison of CID and ETD fragmentation pattern. Analysis of approximately 19,000 peptides derived from both standard proteins and complex protein samples revealed that (i) CID identified 50% more peptides than ETD; (ii) ETD resulted in approximately 20% increase in amino acid sequence coverage over CID; and (iii) combining CID and ETD fragmentation increased the sequence coverage for an average tryptic peptide to 92%. Interestingly, our analysis revealed that nearly 60% of all ETD-identified peptides carried two positive charges, which is in sharp contrast to what has been generally accepted. We also present a novel strategy for automatic validation of peptide assignments based on identification of a peptide by consecutive CID and ETD fragmentation in an alternating mode.

  7. A novel versatile hybrid infusion-multielectrode recording (HIME) system for acute drug delivery and multisite acquisition of neuronal activity in freely moving mice

    PubMed Central

    Senkov, Oleg; Mironov, Andrey; Dityatev, Alexander

    2015-01-01

    To characterize information transfer in defined brain circuits involving multiple brain regions and to evaluate underlying molecular mechanisms and their dysregulation in major brain diseases, a simple and reliable system is ultimately required for electrophysiological recording of local field potentials (LFPs, or local EEG) in combination with local delivery of drugs, enzymes and gene expression-controlling viruses near the place of recording. Here we provide a new design of a versatile reusable hybrid infusion-recording (HIME) system which can be utilized in freely moving mice performing cognitive tasks. The HIME system allows monitoring neuronal activity in multiple layers in several brain structures. Here, we provide examples of bilateral injection and recordings of full spectrum of learning and memory related oscillations, i.e., theta (4–12 Hz), gamma (40–100) and ripple activity (130–150 Hz), in five hippocampal layers as well as in the CA1 and CA2 regions. Furthermore, the system is designed to be used for parallel recordings in the amygdala, cortex and other brain areas, before and after infusion of reagents of interest, either in or off a cognitive test. We anticipate that the HIME system can be particularly convenient to advance functional neuroglycobiological studies and molecular deciphering of mechanisms governing long-term memory consolidation. PMID:26594144

  8. The Cancer Chemotherapeutic Paclitaxel Increases Human and Rodent Sensory Neuron Responses to TRPV1 by Activation of TLR4

    PubMed Central

    Li, Yan; Adamek, Pavel; Zhang, Haijun; Tatsui, Claudio Esteves; Rhines, Laurence D.; Mrozkova, Petra; Li, Qin; Kosturakis, Alyssa K.; Cassidy, Ryan M.; Harrison, Daniel S.; Cata, Juan P.; Sapire, Kenneth; Zhang, Hongmei; Kennamer-Chapman, Ross M.; Jawad, Abdul Basit; Ghetti, Andre; Yan, Jiusheng; Palecek, Jiri

    2015-01-01

    Peripheral neuropathy is dose limiting in paclitaxel cancer chemotherapy and can result in both acute pain during treatment and chronic persistent pain in cancer survivors. The hypothesis tested was that paclitaxel produces these adverse effects at least in part by sensitizing transient receptor potential vanilloid subtype 1 (TRPV1) through Toll-like receptor 4 (TLR4) signaling. The data show that paclitaxel-induced behavioral hypersensitivity is prevented and reversed by spinal administration of a TRPV1 antagonist. The number of TRPV1+ neurons is increased in the dorsal root ganglia (DRG) in paclitaxel-treated rats and is colocalized with TLR4 in rat and human DRG neurons. Cotreatment of rats with lipopolysaccharide from the photosynthetic bacterium Rhodobacter sphaeroides (LPS-RS), a TLR4 inhibitor, prevents the increase in numbers of TRPV1+ neurons by paclitaxel treatment. Perfusion of paclitaxel or the archetypal TLR4 agonist LPS activated both rat DRG and spinal neurons directly and produced acute sensitization of TRPV1 in both groups of cells via a TLR4-mediated mechanism. Paclitaxel and LPS sensitize TRPV1 in HEK293 cells stably expressing human TLR4 and transiently expressing human TRPV1. These physiological effects also are prevented by LPS-RS. Finally, paclitaxel activates and sensitizes TRPV1 responses directly in dissociated human DRG neurons. In summary, TLR4 was activated by paclitaxel and led to sensitization of TRPV1. This mechanism could contribute to paclitaxel-induced acute pain and chronic painful neuropathy. SIGNIFICANCE STATEMENT In this original work, it is shown for the first time that paclitaxel activates peripheral sensory and spinal neurons directly and sensitizes these cells to transient receptor potential vanilloid subtype 1 (TRPV1)-mediated capsaicin responses via Toll-like receptor 4 (TLR4) in multiple species. A direct functional interaction between TLR4 and TRPV1 is shown in rat and human dorsal root ganglion neurons, TLR4/TRPV1

  9. Effects of amyotrophic lateral sclerosis sera on cultured cholinergic neurons

    SciTech Connect

    Touzeau, G.; Kato, A.C.

    1983-03-01

    Dissociated monolayer cultures of chick ciliary ganglion neurons have been used to study the effects of control and ALS sera. The cultured neurons survive and extend neurites for a minimum of 2 weeks in a standard tissue culture medium that contains 10% heat-inactivated human serum. Three parameters of the neurons have been examined when cultured in control and ALS sera for 8 to 12 days: (1) neuronal survival, (2) activity of the enzyme choline acetyltransferase, and (3) synthesis of /sup 3/H-acetylcholine using /sup 3/H-choline as precursor. ALS sera cause a small decrease in these three parameters, but this difference is not significant.

  10. Religious Dissociation and Economic Appraisal in Brazil.

    PubMed

    François Dengah, H J

    2016-04-01

    Research on the association between religion and health often neglects to provide an explicit theoretical mechanism of influence between faith and well-being. This research posits that dissociative behaviors, such as glossolalia, may provide a biological pathway that influences both physiological and psychological health. This paper argues that religious dissociation acts as a moderator between economic stressors and psychobiological appraisal. Brazil, with its economic inequality and preponderance of religious dissociative rituals, provides an ideal context to examine religious dissociation as a moderator of stress. Utilizing data from a cross section of Brazilian faiths, this paper examines: (1) Whether individuals with low socioeconomic status preferentially participate and experience religious dissociative states and (2) whether dissociative states are correlated with greater psychological appraisal of status.

  11. Factors that Contribute to Neuron Survival and Neuron Growth after Injury

    DTIC Science & Technology

    1993-02-03

    Grafts’in it is conceivable that some deficits may be reduced Acute Spinal Cord Lesions by restoting appropriate le’els of neurotransmit- ters in neurona ...the injection of dissociated fetal cells, enriched onal projections, it seems tha, fundamental to the -ith selected neurona ! populations of supraspinal

  12. GABAA receptor-expressing neurons promote consumption in Drosophila melanogaster

    PubMed Central

    Cheung, Samantha K.

    2017-01-01

    Feeding decisions are highly plastic and bidirectionally regulated by neurons that either promote or inhibit feeding. In Drosophila melanogaster, recent studies have identified four GABAergic interneurons that act as critical brakes to prevent incessant feeding. These GABAergic neurons may inhibit target neurons that drive consumption. Here, we tested this hypothesis by examining GABA receptors and neurons that promote consumption. We find that Resistance to dieldrin (RDL), a GABAA type receptor, is required for proper control of ingestion. Knockdown of Rdl in a subset of neurons causes overconsumption of tastants. Acute activation of these neurons is sufficient to drive consumption of appetitive substances and non-appetitive substances and acute silencing of these neurons decreases consumption. Taken together, these studies identify GABAA receptor-expressing neurons that promote Drosophila ingestive behavior and provide insight into feeding regulation. PMID:28362856

  13. Dissociative recombination in planetary ionospheres

    NASA Technical Reports Server (NTRS)

    Fox, J. L.

    1993-01-01

    Ionization in planetary atmospheres can be produced by solar photoionization, photoelectron impact ionization, and, in auroral regions, by impact of precipitating particles. This ionization is lost mainly in dissociative recombination (DR) of molecular ions. Although atomic ions cannot undergo DR, they can be transformed locally through ion-molecule reactions into molecular ions, or they may be transported vertically or horizontally to regions of the atmosphere where such transformations are possible. Because DR reactions tend to be very exothermic, they can be an important source of kinetically or internally excited fragments. In interplanetary thermospheres, the neutral densities decrease exponentially with altitude. Below the homopause (or turbopause), the atmosphere is assumed to be throughly mixed by convection and/or turbulence. Above the homopause, diffusion is the major transport mechanism, and each species is distributed according to its mass, with the logarithmic derivative of the density with repect to altitude given approximately by -1/H, where H = kT/mg is the scale height. In this expression, T is the neutral temperature, g is the local acceleratiion of gravity, and m is the mass of the species. Thus lighter species become relatively more abundant, and heavier species less abundant, as the altitude increases. This variation of the neutral composition can lead to changes in the ion composition; furthermore, as the neutral densities decrease, dissociative recombination becomes more important relative to ion-neutral reactions as a loss mechanism for molecular ions.

  14. Dissociative identity disorder: Medicolegal challenges.

    PubMed

    Farrell, Helen M

    2011-01-01

    Persons with dissociative identity disorder (DID) often present in the criminal justice system rather than the mental health system and perplex experts in both professions. DID is a controversial diagnosis with important medicolegal implications. Defendants have claimed that they committed serious crimes, including rape or murder, while they were in a dissociated state. Asserting that their alter personality committed the bad act, defendants have pleaded not guilty by reason of insanity (NGRI). In such instances, forensic experts are asked to assess the defendant for DID and provide testimony in court. Debate continues over whether DID truly exists, whether expert testimony should be allowed into evidence, and whether it should exculpate defendants for their criminal acts. This article reviews historical and theoretical perspectives on DID, presents cases that illustrate the legal implications and controversies of raising an insanity defense based on multiple personalities, and examines the role of forensic experts asked to comment on DID with the goal of assisting clinicians in the medicolegal assessment of DID in relation to crimes.

  15. Dissociation and functional neurologic disorders.

    PubMed

    Brown, R J

    2017-01-01

    Dissociation has been cited as a possible psychologic mechanism underpinning functional neurologic disorders (FND) since the 19th century. Since that time, changes in psychiatric classification have created confusion about what the term dissociation actually means. The available evidence suggests that it now refers to at least two qualitatively distinct types of phenomena: detachment (an altered state of consciousness characterized by a sense of separation from the self or world) and compartmentalization (a reversible loss of voluntary control over apparently intact processes and functions), as well as their underlying mechanisms. This chapter considers some of the problems with conflating these phenomena under a single heading as well as the relationship between detachment, compartmentalization, and FND. It is argued that FNDs are fundamentally compartmentalization disorders, but that detachment is often part of the clinical picture and may contribute to the development and maintenance of functional symptoms in many cases. By this view, understanding compartmentalization requires an appreciation of the mechanisms involved in controlling and accessing mental processes and contents. Two possible mechanisms in this regard are described and the evidence for these is considered, followed by a discussion of clinical and empiric implications.

  16. Dissociative disorders and suicidality in psychiatric outpatients.

    PubMed

    Foote, Brad; Smolin, Yvette; Neft, Deborah I; Lipschitz, Deborah

    2008-01-01

    Although it is common for patients with dissociative disorders to report a history of suicide attempts, there is very little data systematically comparing suicidality in patients with dissociative disorders versus patients without these disorders. The subjects in our study were 231 patients consecutively admitted to an inner-city, hospital-based outpatient psychiatric clinic. Eighty-two of these patients completed structured interviews for dissociative disorders, borderline personality disorder, and trauma history (dissociative disorders interview schedule) and for posttraumatic stress disorder and substance abuse (Structured Clinical Interview for DSM-IV). Patients receiving a dissociative disorder diagnosis were compared with nondissociative patients on measures of self-harm and suicidality. Presence of a dissociative disorder was strongly associated with all measures of self-harm and suicidality. When we focused on patients with a history of multiple suicide attempts, significant associations were found between several diagnoses (dissociative disorder; borderline personality disorder; posttraumatic stress disorder; alcohol abuse/dependence) and multiple suicide attempter status. When these diagnoses were entered in a logistic regression, a highly significant association remained for dissociative diagnosis and multiple suicide attempter status (odds ratio, 15.09; 95% confidence interval, 2.67-85.32; p = 0.002). Dissociative disorders are commonly overlooked in studies of suicidality, but in this population they were the strongest predictor of multiple suicide attempter status.

  17. Dissociative Recombination without a Curve Crossing

    NASA Technical Reports Server (NTRS)

    Guberman, Steven L.

    1994-01-01

    Ab initio calculations show that a curve crossing is not always needed for a high dissociative- recombination cross section. For HeH(+), in which no neutral states cross the ion potential curve, dissociative recombination is driven by the nuclear kinetic-energy operator on adiabatic potential curves. The kinetic-energy derivative operator allows for capture into repulsive curves that are outside of the classical turning points for the nuclear motion. The dominant dissociative route is the C (2)Sigma(+) state leading to H(n = 2) atoms. An analogous mechanism is proposed for the dissociative recombination of H3(+).

  18. Mirror writing and a dissociative identity disorder.

    PubMed

    Le, Catherine; Smith, Joyce; Cohen, Lewis

    2009-01-01

    Individuals with dissociative identity disorder (DID) have been known to show varied skills and talents as they change from one dissociative state to another. For example, case reports have described people who have changed their handedness or have spoken foreign languages during their dissociative states. During an interview with a patient with DID, a surprising talent emerged when she wrote a sentence for the Folstein Mini-Mental State Exam-mirror writing. It is not known whether her mirror writing had a deeper level of meaning; however, it does emphasize the idiosyncratic nature of dissociative identity disorder.

  19. Dissociative symptoms and dissociative disorder comorbidity in patients with obsessive-compulsive disorder.

    PubMed

    Belli, Hasan; Ural, Cenk; Vardar, Melek Kanarya; Yesılyurt, Sema; Oncu, Fatıh

    2012-10-01

    The present study attempted to assess the dissociative symptoms and overall dissociative disorder comorbidity in patients with obsessive-compulsive disorder (OCD). In addition, we examined the relationship between the severity of obsessive-compulsive symptoms and dissociative symptoms. All patients admitted for the first time to the psychiatric outpatient unit were included in the study. Seventy-eight patients had been diagnosed as having OCD during the 2-year study period. Patients had to meet the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for OCD. Most (76.9%; n = 60) of the patients were female, and 23.1% (n = 18) of the patients were male. Dissociation Questionnaire was used to measure dissociative symptoms. The Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Dissociative Disorders interviews and Yale-Brown Obsessive Compulsive Checklist and Severity Scale were used. Eleven (14%) of the patients with OCD had comorbid dissociative disorder. The most prevalent disorder in our study was dissociative depersonalization disorder. Dissociative amnesia and dissociative identity disorder were common as well. The mean Yale-Brown score was 23.37 ± 7.27 points. Dissociation Questionnaire scores were between 0.40 and 3.87 points, and the mean was 2.23 ± 0.76 points. There was a statistically significant positive correlation between Yale-Brown points and Dissociation Questionnaire points. We conclude that dissociative symptoms among patients with OCD should alert clinicians for the presence of a chronic and complex dissociative disorder. Clinicians may overlook an underlying dissociative process in patients who have severe symptoms of OCD. However, a lack of adequate response to cognitive-behavioral and drug therapy may be a consequence of dissociative process.

  20. Netrin-G1 regulates fear-like and anxiety-like behaviors in dissociable neural circuits

    PubMed Central

    Zhang, Qi; Sano, Chie; Masuda, Akira; Ando, Reiko; Tanaka, Mika; Itohara, Shigeyoshi

    2016-01-01

    In vertebrate mammals, distributed neural circuits in the brain are involved in emotion-related behavior. Netrin-G1 is a glycosyl-phosphatidylinositol-anchored synaptic adhesion molecule whose deficiency results in impaired fear-like and anxiety-like behaviors under specific circumstances. To understand the cell type and circuit specificity of these responses, we generated netrin-G1 conditional knockout mice with loss of expression in cortical excitatory neurons, inhibitory neurons, or thalamic neurons. Genetic deletion of netrin-G1 in cortical excitatory neurons resulted in altered anxiety-like behavior, but intact fear-like behavior, whereas loss of netrin-G1 in inhibitory neurons resulted in attenuated fear-like behavior, but intact anxiety-like behavior. These data indicate a remarkable double dissociation of fear-like and anxiety-like behaviors involving netrin-G1 in excitatory and inhibitory neurons, respectively. Our findings support a crucial role for netrin-G1 in dissociable neural circuits for the modulation of emotion-related behaviors, and provide genetic models for investigating the mechanisms underlying the dissociation. The results also suggest the involvement of glycosyl-phosphatidylinositol-anchored synaptic adhesion molecules in the development and pathogenesis of emotion-related behavior. PMID:27345935

  1. The multidimensional inventory of dissociation (MID): A comprehensive measure of pathological dissociation.

    PubMed

    Dell, Paul F

    2006-01-01

    This article describes the development and validation of the Multidimensional Inventory of Dissociation (MID). The MID is a 218-item, self-administered, multiscale instrument that comprehensively assesses the phenomenological domain of pathological dissociation and diagnoses the dissociative disorders. The MID measures 14 major facets of pathological dissociation; it has 23 dissociation diagnostic scales that simultaneously operationalize (1) the subjective/ phenomenological domain of pathological dissociation and (2) the hypothesized dissociative symptoms of dissociative identity disorder (Dell, 2001a). The MID was designed for clinical research and for diagnostic assessment of patients who present with a mixture of dissociative, posttraumatic, and borderline symptoms. The MID demonstrated internal reliability, temporal stability, convergent validity, discriminant validity, and construct validity. The MID also exhibited incremental validity over the Dissociative Experiences Scale (DES) by predicting an additional 18% of the variance in weighted abuse scores on the Traumatic Experiences Questionnaire (TEQ). Confirmatory factor analysis (CFA) did not support a one-factor model of the MID's clinical scales (i.e., the 14 facets and the 23 diagnostic symptoms). In contrast, however, CFA of the MID's factor scales (Dell & Lawson, 2005) has strongly supported a one-factor model. It was concluded that both the MID's 168 dissociation items and the construct of pathological dissociation have a second-order, unifactorial structure.

  2. Riluzole But Not Melatonin Ameliorates Acute Motor Neuron Degeneration and Moderately Inhibits SOD1-Mediated Excitotoxicity Induced Disrupted Mitochondrial Ca2+ Signaling in Amyotrophic Lateral Sclerosis

    PubMed Central

    Jaiswal, Manoj Kumar

    2017-01-01

    Selective motoneurons (MNs) degeneration in the brain stem, hypoglossal motoneurons (HMNs), and the spinal cord resulting in patients paralysis and eventual death are prominent features of amyotrophic lateral sclerosis (ALS). Previous studies have suggested that mitochondrial respiratory impairment, low Ca2+ buffering and homeostasis and excitotoxicity are the pathological phenotypes found in mice, and cell culture models of familial ALS (fALS) linked with Cu/Zn-superoxide dismutase 1 (SOD1) mutation. In our study, we aimed to understand the impact of riluzole and melatonin on excitotoxicity, neuronal protection and Ca2+ signaling in individual HMNs ex vivo in symptomatic adult ALS mouse brain stem slice preparations and in WT and SOD1-G93A transfected SH-SY5Y neuroblastoma cell line using fluorescence microscopy, calcium imaging with high speed charged coupled device camera, together with immunohistochemistry, cell survival assay and histology. In our experiments, riluzole but not melatonin ameliorates MNs degeneration and moderately inhibit excitotoxicity and cell death in SH-SY5YWT or SH-SY5YG93A cell lines induced by complex IV blocker sodium azide. In brain stem slice preparations, riluzole significantly inhibit HMNs cell death induced by inhibiting the mitochondrial electron transport chain by Na-azide. In the HMNs of brainstem slice prepared from adult (14–15 weeks) WT, and corresponding symptomatic SOD1G93A mice, we measured the effect of riluzole and melatonin on [Ca2+]i using fura-2 AM ratiometric calcium imaging in individual MNs. Riluzole caused a significant decrease in [Ca2+]i transients and reversibly inhibited [Ca2+]i transients in Fura-2 AM loaded HMNs exposed to Na-azide in adult symptomatic SOD1G93A mice. On the contrary, melatonin failed to show similar effects in the HMNs of WT and SOD1G93A mice. Intrinsic nicotinamide adenine dinucleotide (NADH) fluorescence, an indicator of mitochondrial metabolism and health in MNs, showed enhanced

  3. Infant acute myocarditis mimicking acute myocardial infarction

    PubMed Central

    Tilouche, Samia; Masmoudi, Tasnim; Sahnoun, Maha; Chkirbène, Youssef; Mestiri, Sarra; Boughamoura, Lamia; Ben Dhiab, Mohamed; Souguir, Mohamed Kamel

    2016-01-01

    Myocarditis is an inflammatory disease of the myocardium with heterogeneous clinical manifestations and progression. In clinical practice, although there are many methods of diagnosis of acute myocarditis, the diagnosis remains an embarrassing dilemma for clinicians. The authors report the case of 9-month-old infant who was brought to the Pediatric Emergency Department with sudden onset dyspnea. Examination disclosed heart failure and resuscitation was undertaken. The electrocardiogram showed an ST segment elevation in the anterolateral leads with a mirror image. Cardiac enzyme tests revealed a significant elevation of troponin and creatine phosphokinase levels. A diagnosis of acute myocardial infarction was made, and heparin therapy was prescribed. The infant died on the third day after admission with cardiogenic shock. The autopsy showed dilatation of the ventricles and massive edema of the lungs. Histological examinations of myocardium samples revealed the presence of a marked lymphocytic infiltrate dissociating myocardiocytes. Death was attributed to acute myocarditis. The authors call attention to the difficulties of differential diagnosis between acute myocarditis and acute myocardial infarction especially in children, and to the important therapeutic implications of a correct diagnosis. PMID:28210569

  4. The Dissociative Recombination of OH(+)

    NASA Technical Reports Server (NTRS)

    Guberman, Steven L.

    1995-01-01

    Theoretical quantum chemical calculations of the cross sections and rates for the dissociative recombination of the upsilon = 0 level of the ground state of OH(+) show that recombination occurs primarily along the 2 (2)Pi diabatic route. The products are 0((1)D) and a hot H atom with 6.1 eV kinetic energy. The coupling to the resonances is very small and the indirect recombination mechanism plays only a minor role. The recommended value for the rate coefficient is (6.3 +/- 0.7) x 10(exp -9)x (T(e)/1300)(exp -0.48) cu.cm/s for 10 less than T(e) less than 1000 K.

  5. GABAergic neurons of the medial septum play a nodal role in facilitation of nociception-induced affect

    PubMed Central

    Ang, Seok Ting; Lee, Andy Thiam Huat; Foo, Fang Chee; Ng, Lynn; Low, Chian-Ming; Khanna, Sanjay

    2015-01-01

    The present study explored the functional details of the influence of medial septal region (MSDB) on spectrum of nociceptive behaviours by manipulating intraseptal GABAergic mechanisms. Results showed that formalin-induced acute nociception was not affected by intraseptal microinjection of bicuculline, a GABAA receptor antagonist, or on selective lesion of septal GABAergic neurons. Indeed, the acute nociceptive responses were dissociated from the regulation of sensorimotor behaviour and generation of theta-rhythm by the GABAergic mechanisms in MSDB. The GABAergic lesion attenuated formalin-induced unconditioned cellular response in the anterior cingulate cortex (ACC) and blocked formalin-induced conditioned place avoidance (F-CPA), and as well as the contextual fear induced on conditioning with brief footshock. The effects of lesion on nociceptive-conditioned cellular responses were, however, variable. Interestingly, the lesion attenuated the conditioned representation of experimental context in dorsal hippocampus field CA1 in the F-CPA task. Collectively, the preceding suggests that the MSDB is a nodal centre wherein the GABAergic neurons mediate nociceptive affect-motivation by regulating cellular mechanisms in ACC that confer an aversive value to the noxious stimulus. Further, in conjunction with a modulatory influence on hippocampal contextual processing, MSDB may integrate affect with context as part of associative learning in the F-CPA task. PMID:26487082

  6. GABAergic neurons of the medial septum play a nodal role in facilitation of nociception-induced affect.

    PubMed

    Ang, Seok Ting; Lee, Andy Thiam Huat; Foo, Fang Chee; Ng, Lynn; Low, Chian-Ming; Khanna, Sanjay

    2015-10-21

    The present study explored the functional details of the influence of medial septal region (MSDB) on spectrum of nociceptive behaviours by manipulating intraseptal GABAergic mechanisms. Results showed that formalin-induced acute nociception was not affected by intraseptal microinjection of bicuculline, a GABAA receptor antagonist, or on selective lesion of septal GABAergic neurons. Indeed, the acute nociceptive responses were dissociated from the regulation of sensorimotor behaviour and generation of theta-rhythm by the GABAergic mechanisms in MSDB. The GABAergic lesion attenuated formalin-induced unconditioned cellular response in the anterior cingulate cortex (ACC) and blocked formalin-induced conditioned place avoidance (F-CPA), and as well as the contextual fear induced on conditioning with brief footshock. The effects of lesion on nociceptive-conditioned cellular responses were, however, variable. Interestingly, the lesion attenuated the conditioned representation of experimental context in dorsal hippocampus field CA1 in the F-CPA task. Collectively, the preceding suggests that the MSDB is a nodal centre wherein the GABAergic neurons mediate nociceptive affect-motivation by regulating cellular mechanisms in ACC that confer an aversive value to the noxious stimulus. Further, in conjunction with a modulatory influence on hippocampal contextual processing, MSDB may integrate affect with context as part of associative learning in the F-CPA task.

  7. [Dissociative disorders: neurologists and psychiatrists working together].

    PubMed

    Hubschmid, Monica; Aybek, Selma; Vingerhoets, François; Berney, Alexandre

    2008-02-13

    Dissociative disorders often have an atypical neurological presentation requiring a complex diagnostic process at the interface between neurology and psychiatry. A strong interdisciplinary collaboration is needed for diagnosis restitution and patient treatment. Current knowledge is still scarce but recent studies in clinical neuroscience enrich this field. This article presents the main aspects of dissociative disorders and suggests a treatment framework.

  8. Dissociations, Developmental Psychology, and Pedagogical Design

    ERIC Educational Resources Information Center

    Lillard, Angeline

    2006-01-01

    Although dissociations in children's responses are sometimes about "getting it right" for an experimenter, they might also often reflect differences between conscious and subconscious processing that are not geared to correct performance. Research with adults also reveals many cases of dissociation, and adults can more easily be subjected to…

  9. Verbal-Behavioral Dissociations in Development

    ERIC Educational Resources Information Center

    Woolley, Jacqueline D.

    2006-01-01

    Verbal and behavioral measures of children's knowledge are frequently dissociated. These situations represent a largely untapped but important resource for furthering an understanding of human cognition. In this paper, verbal-behavioral dissociations in children are discussed and analyzed, drawing from a wide range of domains. The article explores…

  10. Dissociative depression among women in the community.

    PubMed

    Sar, Vedat; Akyüz, Gamze; Oztürk, Erdinç; Alioğlu, Firdevs

    2013-01-01

    This study screened the prevalence and correlates of dissociative disorders among depressive women in the general population. The Dissociative Disorders Interview Schedule and the posttraumatic stress disorder (PTSD) and borderline personality disorder sections of the Structured Clinical Interview for DSM-IV were administered to 628 women in 500 homes. The prevalence of current major depressive episode was 10.0%. Of the women, 26 (40.6%) had the lifetime diagnosis of a DSM-IV, dissociative disorder, yielding a prevalence of 4.1% for dissociative depression. This group was younger (mean age = 30.7 years) than the nondissociative depression women (mean age = 39.6 years). There was no difference between the 2 groups on comorbid somatization disorder, PTSD, or borderline personality disorder. Besides suicide attempts, the dissociative group was characterized by secondary features of dissociative identity disorder; Schneiderian symptoms; borderline personality disorder criteria; and extrasensory perceptions, including possession experiences. They reported suicidality, thoughts of guilt and worthlessness, diminished concentration and indecisiveness, and appetite and weight changes more frequently than the nondissociative group. Early cessation of school education and childhood sexual abuse were frequently reported by the dissociative depression group. With its distinct features, the concept of dissociative depression may facilitate understanding of treatment resistance in, development of better psychotherapy strategies for, and new thinking on the neurobiology and pharmacotherapy of depressive disorders.

  11. [Dissociative disorder and self-injury].

    PubMed

    Noma, Shun'ichi

    2011-01-01

    Both the number of patients with dissociative disorder and that of those with self-injury have been increasing since the end of the twentieth century, suggesting that dissociation and self-injury might be closely related. When dissociative disorder coexists with self-injury, it implies self-punishment and a wish to be understood by others. Although many cases of self-injury observed since 2000 lacked traumatic experiences and were not accompanied by pathological dissociative symptoms, the patients did have dissociative tendencies. According to the results of our study examining self-injury in patients with eating disorders, we observed that self-injury, dissociative tendency and insulation from others are related to each other. This suggests that affects, sensations and representations are dissociated, losing their normal response order, and that the pervasive idea that "pain=secure" is formed in a patient from childhood based on influence from their parents. Self-injury appears to be an activation of this pervasive idea that is triggered by a stressful situation, when the dissociative psychological segmentation of effects and their representations are present in the background.

  12. A Hierarchical Process-Dissociation Model

    ERIC Educational Resources Information Center

    Rouder, Jeffrey N.; Lu, Jun; Morey, Richard D.; Sun, Dongchu; Speckman, Paul L.

    2008-01-01

    In fitting the process-dissociation model (L. L. Jacoby, 1991) to observed data, researchers aggregate outcomes across participant, items, or both. T. Curran and D. L. Hintzman (1995) demonstrated how biases from aggregation may lead to artifactual support for the model. The authors develop a hierarchical process-dissociation model that does not…

  13. Dissociation in schizophrenia and borderline personality disorder

    PubMed Central

    Pec, Ondrej; Bob, Petr; Raboch, Jiri

    2014-01-01

    Background Dissociation likely plays a key role in schizophrenia and borderline personality disorder (BPD), although empirical studies that compare specific manifestations of these symptoms in schizophrenia and BPD are rare. In this context, the purpose of this study was to compare the occurrence of dissociative and other psychopathological symptoms in these disorders, and to assess the possible influence of antipsychotic medication on the dissociative symptoms. Methods We assessed 31 patients with schizophrenia and 36 patients with BPD. Dissociative symptoms were measured by the Dissociative Experiences Scale (DES), symptoms related to stress and traumatic experiences were assessed using the Trauma Symptom Checklist-40 (TSC-40), and other psychopathological symptoms were measured with the Health of the Nation Outcome Scales (HoNOS). We also assessed actual daily doses of antipsychotic medication in chlorpromazine equivalents in all participants. Results The results show that symptoms of traumatic stress measured by the TSC-40 had significantly higher scores in the BPD group. The data also show that dissociative symptoms (DES) were significantly correlated with symptoms of traumatic stress (TSC-40) and with symptoms assessed by the HoNOS. Remarkably significant correlations were found between levels of antipsychotic medication and the DES and between antipsychotic medication and the depersonalization/derealization component of the DES in BPD patients. Conclusion The results support an important role of dissociative processes in schizophrenia and BPD and suggest a significant relationship between manifestations of dissociative symptoms in BPD and antipsychotic medication. PMID:24672239

  14. Dissociative recombination of highly symmetric polyatomic ions.

    PubMed

    Douguet, Nicolas; Orel, Ann E; Greene, Chris H; Kokoouline, Viatcheslav

    2012-01-13

    A general first-principles theory of dissociative recombination is developed for highly symmetric molecular ions and applied to H(3)O(+) and CH(3)(+), which play an important role in astrophysical, combustion, and laboratory plasma environments. The theoretical cross sections obtained for the dissociative recombination of the two ions are in good agreement with existing experimental data from storage ring experiments.

  15. Dissociation and the Development of Psychopathology.

    ERIC Educational Resources Information Center

    Putnam, Frank W.; Trickett, Penelope K.

    This paper reviews the research on dissociation and the development of psychopathology in children and adolescents. Definitions and dimensions of dissociation are addressed, noting its range from normative daydreaming to the extremes found in individuals with multiple personality disorder. Memory dysfunctions, disturbances of identity, passive…

  16. Dissociation heat transfer characteristics of methane hydrates

    SciTech Connect

    Kamath, V.A.; Holder, G.D.

    1987-02-01

    Knowledge of the interfacial heat transfer phenomenon during the dissociation of gas hydrates is essential in modeling the hydrate dissociation process. Such knowledge has applications in natural gas processing, storage, or transportation; in the drilling and recovery of oil and gas in the presence of gas hydrates; in the desalination of sea water; and in the production of natural gas from hydrate reservoirs. The process of hydrate dissociation is a unique phenomenon in which gas and water are simultaneously produced at the dissociated hydrate surface and play an important role in the mechanism of heat transfer to hydrates. An earlier study of propane hydrate dissociation showed that hydrate dissociation is a heat-transfer-limited process and somewhat similar to the nucleate boiling of liquids. In the present study, heat transfer limitations for methane hydrate dissociation were studied for two reasons. First, a comparison of the results of this study with propane hydrate was desired. Second, the effect of hydrate structure and gas molecule type on the rate of heat transfer during hydrate dissociation was sought.

  17. The generation of rhythmic activity in dissociated cultures of rat spinal cord.

    PubMed

    Streit, J; Tscherter, A; Heuschkel, M O; Renaud, P

    2001-07-01

    Locomotion in vertebrates is controlled by central pattern generators in the spinal cord. The roles of specific network architecture and neuronal properties in rhythm generation by such spinal networks are not fully understood. We have used multisite recording from dissociated cultures of embryonic rat spinal cord grown on multielectrode arrays to investigate the patterns of spontaneous activity in randomised spinal networks. We were able to induce similar patterns of rhythmic activity in dissociated cultures as in slice cultures, although not with the same reliability and not always with the same protocols. The most reliable rhythmic activity was induced when a partial disinhibition of the network was combined with an increase in neuronal excitability, suggesting that both recurrent synaptic excitation and neuronal excitability contribute to rhythmogenesis. During rhythmic activity, bursts started at several sites and propagated in variable ways. However, the predominant propagation patterns were independent of the protocol used to induce rhythmic activity. When synaptic transmission was blocked by CNQX, APV, strychnine and bicuculline, asynchronous low-rate activity persisted at approximately 50% of the electrodes and approximately 70% of the sites of burst initiation. Following the bursts, the activity in the interval was transiently suppressed below the level of intrinsic activity. The degree of suppression was proportional to the amount of activity in the preceding burst. From these findings we conclude that rhythmic activity in spinal cultures is controlled by the interplay of intrinsic neuronal activity and recurrent excitation in neuronal networks without the need for a specific architecture.

  18. The Shutdown Dissociation Scale (Shut-D)

    PubMed Central

    Schalinski, Inga; Schauer, Maggie; Elbert, Thomas

    2015-01-01

    The evolutionary model of the defense cascade by Schauer and Elbert (2010) provides a theoretical frame for a short interview to assess problems underlying and leading to the dissociative subtype of posttraumatic stress disorder. Based on known characteristics of the defense stages “fright,” “flag,” and “faint,” we designed a structured interview to assess the vulnerability for the respective types of dissociation. Most of the scales that assess dissociative phenomena are designed as self-report questionnaires. Their items are usually selected based on more heuristic considerations rather than a theoretical model and thus include anything from minor dissociative experiences to major pathological dissociation. The shutdown dissociation scale (Shut-D) was applied in several studies in patients with a history of multiple traumatic events and different disorders that have been shown previously to be prone to symptoms of dissociation. The goal of the present investigation was to obtain psychometric characteristics of the Shut-D (including factor structure, internal consistency, retest reliability, predictive, convergent and criterion-related concurrent validity). A total population of 225 patients and 68 healthy controls were accessed. Shut-D appears to have sufficient internal reliability, excellent retest reliability, high convergent validity, and satisfactory predictive validity, while the summed score of the scale reliably separates patients with exposure to trauma (in different diagnostic groups) from healthy controls. The Shut-D is a brief structured interview for assessing the vulnerability to dissociate as a consequence of exposure to traumatic stressors. The scale demonstrates high-quality psychometric properties and may be useful for researchers and clinicians in assessing shutdown dissociation as well as in predicting the risk of dissociative responding. PMID:25976478

  19. Dissociative electron attachment to water

    NASA Astrophysics Data System (ADS)

    Haxton, Daniel James

    Dissociative electron attachment to water, H2O+e-→ H+OH-3.27eV H2+O-3.56eV H-+OHX P2 4.35eVH+H+O-8.04e VH-+OH* S2 8.38eVH-+H+O 8.75eV 0.1 is a physical process that has been studied since 1930[1]. It may be viewed as an inherently is non-Born-Oppenheimer process, for the initial state belongs to the electronic continuum, and the final state is electronically bound. As such, it presents a particular challenge for theory. We present a first-principles theoretical treatment of this process, in which we calculate the cross sections for production of the three major atom - diatom products observed by experiment, H2 + O-, H- + OH (X 2pi), and H- + OH (2Sigma). These states comprise the bulk of the experimentally determined cross section. In the present work we employ a Born-Oppenheimer expansion of the wavefunction for nuclear and electronic motion, and treat both quantum mechanically. The adiabatic treatment of the electronic motion incorporates multiconfiguration, correlated wavefunctions and includes an explicit treatment of the electronic continuum. For the nuclear dynamics we incorporate the full dimensionality of nuclear motion, including the three internal degrees of freedom and the effect of rotation. This is the first ab initio treatment of dissociative electron attachment which incorporates more than one degree of freedom in the nuclear dynamics. The first step in our Born-Oppenheimer treatment is to calculate adiabatic potential energy surfaces for the three metastable electronic states which are involved, the 2B1, 2A1, and 2B 2 electronic Feshbach resonances. Global potential energy surfaces are defined which incorporate the results of fixed-nuclei, ab initio calculations: quantum-mechanical electron scattering calculations using the complex Kohn method are performed and augmented by the results of large-scale configuration-interaction calculations performed in a restricted Hilbert space. The global surfaces are defined by a very accurate fit combining a 35

  20. Dissociation of dicarboxylate and disulfonate dianions.

    PubMed

    Ard, Shaun; Mirsaleh-Kohan, Nasrin; Steill, Jeffrey D; Oomens, Jos; Nielsen, Steen Brøndsted; Compton, R N

    2010-03-07

    Collision-induced dissociation (CID), along with infrared multiple photon dissociation/detachment (IRMPD) techniques, is utilized to study a series of doubly substituted aromatic dianions containing sulfonate and carboxylate functionalities (1,2- and 1,3-benzenedisulfonate, 1,5-naphthalenedisulfonate, 2,6-naphthalenedisulfonate, 4-sulfobenzoate, 2,6-naphthalenedicarboxylate, and terephthalate dianions). The molecules were chosen because of the electronegativity of the CO(2) and SO(3) moieties along with their varied spatial separation in order to investigate the effect of the repulsive Coulomb barrier (RCB) on the dianions' respective dissociation pathways. Density functional theory calculations of the structures, electron detachment and dissociation energies, as well as vibrational frequencies are performed. Calculated infrared active vibrational frequencies are largely in agreement with the IRMPD spectra which provide support for interpretations based upon computed energies. Calculated and experimental results show that fragmentation dominates over electron detachment as the lowest energy dissociation pathway for these systems and the nature of this dissociation is dictated by properties of the substituent group. CID and IRMPD of dianions with two sulfonate groups (SO(3)(-)) resulted in a single dissociation channel leading to observation of SO(3)(-) and its anion conjugate pair, whereas the carboxylate (CO(2)(-)) containing dianions dissociated via loss of one or both CO(2) molecules and an electron. The SO(3)(-) collisional dissociation exhibited a clear energetic threshold toward ionic fragmentation with an isomeric dependence that is in reasonable agreement with a simple electrostatic model of the RCB, as well as with published reports on electron photodetachment. The loss of one or both CO(2) units and an electron from CID of the carboxylate dianions appeared with no threshold (dissociation occurs with no collision gas), implying these dianions to be

  1. Dorsal Raphe Dopamine Neurons Represent the Experience of Social Isolation

    PubMed Central

    Matthews, Gillian A.; Nieh, Edward H.; Vander Weele, Caitlin M.; Halbert, Sarah A.; Pradhan, Roma V.; Yosafat, Ariella S.; Glober, Gordon F.; Izadmehr, Ehsan M.; Thomas, Rain E.; Lacy, Gabrielle D.; Wildes, Craig P.; Ungless, Mark A.; Tye, Kay M.

    2016-01-01

    Summary The motivation to seek social contact may arise from either positive or negative emotional states, as social interaction can be rewarding and social isolation can be aversive. While ventral tegmental area (VTA) dopamine (DA) neurons may mediate social reward, a cellular substrate for the negative affective state of loneliness has remained elusive. Here, we identify a functional role for DA neurons in the dorsal raphe nucleus (DRN), in which we observe synaptic changes following acute social isolation. DRN DA neurons show increased activity upon social contact following isolation, revealed by in vivo calcium imaging. Optogenetic activation of DRN DA neurons increases social preference but causes place avoidance. Furthermore, these neurons are necessary for promoting rebound sociability following an acute period of isolation. Finally, the degree to which these neurons modulate behavior is predicted by social rank, together supporting a role for DRN dopamine neurons in mediating a loneliness-like state. PaperClip PMID:26871628

  2. Membrane potential dye imaging of ventromedial hypothalamus neurons from adult mice to study glucose sensing.

    PubMed

    Vazirani, Reema P; Fioramonti, Xavier; Routh, Vanessa H

    2013-11-27

    Studies of neuronal activity are often performed using neurons from rodents less than 2 months of age due to the technical difficulties associated with increasing connective tissue and decreased neuronal viability that occur with age. Here, we describe a methodology for the dissociation of healthy hypothalamic neurons from adult-aged mice. The ability to study neurons from adult-aged mice allows the use of disease models that manifest at a later age and might be more developmentally accurate for certain studies. Fluorescence imaging of dissociated neurons can be used to study the activity of a population of neurons, as opposed to using electrophysiology to study a single neuron. This is particularly useful when studying a heterogeneous neuronal population in which the desired neuronal type is rare such as for hypothalamic glucose sensing neurons. We utilized membrane potential dye imaging of adult ventromedial hypothalamic neurons to study their responses to changes in extracellular glucose. Glucose sensing neurons are believed to play a role in central regulation of energy balance. The ability to study glucose sensing in adult rodents is particularly useful since the predominance of diseases related to dysfunctional energy balance (e.g. obesity) increase with age.

  3. Trimethyltin retinopathy: relationship of subcellular response to neuronal subspecialization

    SciTech Connect

    Bouldin, T.W.; Goines, N.D.; Krigman, M.R.

    1984-03-01

    Retinal neurons from rats acutely intoxicated with trimethyltin (TMT) were examined by light and electron microscopy to determine if there is a relationship between the subcellular response of a neuron to TMT and its morphologic subspecialization. Subcellular pathologic alterations were present in neurons from all three cellular layers of the sensory retina. However, the type and degree of subcellular response varied among the highly subspecialized neurons of the different retinal layers. Clusters of dense-cored vesicles and tubules were mainly limited to neurons of the ganglion-cell layer, large accumulations of dense bodies were mainly limited to neurons of the inner nuclear layer, and neuronal necrosis was mainly limited to the photoreceptor cells. The inner segment of the photoreceptor cell shared with the perikaryon of more conventional neurons a special vulnerability to TMT cytotoxicity. Our results suggest that the subspecialization of neurons affects the type and the degree of subcellular response to TMT.

  4. Double dissociation of 'what' and 'where' processing in auditory cortex.

    PubMed

    Lomber, Stephen G; Malhotra, Shveta

    2008-05-01

    Studies of cortical connections or neuronal function in different cerebral areas support the hypothesis that parallel cortical processing streams, similar to those identified in visual cortex, may exist in the auditory system. However, this model has not yet been behaviorally tested. We used reversible cooling deactivation to investigate whether the individual regions in cat nonprimary auditory cortex that are responsible for processing the pattern of an acoustic stimulus or localizing a sound in space could be doubly dissociated in the same animal. We found that bilateral deactivation of the posterior auditory field resulted in deficits in a sound-localization task, whereas bilateral deactivation of the anterior auditory field resulted in deficits in a pattern-discrimination task, but not vice versa. These findings support a model of cortical organization that proposes that identifying an acoustic stimulus ('what') and its spatial location ('where') are processed in separate streams in auditory cortex.

  5. From state dissociation to status dissociatus.

    PubMed

    Antelmi, Elena; Ferri, Raffaele; Iranzo, Alex; Arnulf, Isabelle; Dauvilliers, Yves; Bhatia, Kailash P; Liguori, Rocco; Schenck, Carlos H; Plazzi, Giuseppe

    2016-08-01

    The states of being are conventionally defined by the simultaneous occurrence of behavioral, neurophysiological and autonomic descriptors. State dissociation disorders are due to the intrusion of features typical of a different state into an ongoing state. Disorders related to these conditions are classified according to the ongoing main state and comprise: 1) Dissociation from prevailing wakefulness as seen in hypnagogic or hypnopompic hallucinations, automatic behaviors, sleep drunkenness, cataplexy and sleep paralysis 2) Dissociation from rapid eye movement (REM) sleep as seen in REM sleep behavior disorder and lucid dreaming and 3) Dissociation from NREM sleep as seen in the disorders of arousal. The extreme expression of states dissociation is characterized by the asynchronous occurrence of the various components of the different states that prevents the recognition of any state of being. This condition has been named status dissociatus. According to the underlying disorders/diseases and to their severity, among status dissociatus we may recognize disorders in which such an extreme dissociation occurs only at night time or intermittently (i.e., autoimmune encephalopathies, narcolepsy type 1 and IgLON5 parasomnia), and others in which it occurs nearly continuously with complete loss of any conventionally defined state of being, and of the circadian pattern (agrypnia excitata). Here, we render a comprehensive review of all diseases/disorders associated with state dissociation and status dissociatus and propose a critical classification of this complex scenario.

  6. Objective assessment of peritraumatic dissociation: psychophysiological indicators.

    PubMed

    Griffin, M G; Resick, P A; Mechanic, M B

    1997-08-01

    This study aims to investigate psychophysiological changes associated with peritraumatic dissociation in female victims of recent rape and assess the relation between these changes and symptoms of post-traumatic stress disorder (PTSD). Samples included 85 rape victims from local police departments (84%), plus victim assistance agencies (15%), and hospitals (1%). Results indicate that there is a relatively normal distribution of peritraumatic dissociative symptoms during rape-related trauma. The Peritraumatic Dissociation Index demonstrated good internal consistency in a group of recent rape victims, which supports the use of this type of scale for assessing peritraumatic dissociation in trauma victims. Individuals in the high peritraumatic dissociation group showed a significantly different pattern of physiological responses from those of the low dissociation group. These responses are due to the suppression of autonomic physiological responses. Moreover, this group also contained a larger proportion of subjects (94%) identified as meeting PTSD symptom criteria. Thus, these findings support the idea that there is a dissociative subtype of persons with PTSD who may not process traumatic information, which may lead to greater levels of PTSD symptoms.

  7. Peritraumatic dissociation and physiological response to trauma-relevant stimuli in Vietnam combat veterans with posttraumatic stress disorder.

    PubMed

    Kaufman, Milissa L; Kimble, Matthew O; Kaloupek, Danny G; McTeague, Lisa M; Bachrach, Peter; Forti, Allison M; Keane, Terence M

    2002-03-01

    A recent study found that female rape victims with acute posttraumatic stress disorder (PTSD) who received a high score on the Peritraumatic Dissociative Experiences Questionnaire exhibited suppression of physiological responses during exposure to trauma-related stimuli. The goal of our present study was to test whether the same relationship holds true for male Vietnam combat veterans with chronic PTSD, using secondary analyses applied to data derived from a Veteran's Affairs Cooperative Study. Vietnam combat veterans (N = 1238) completed measures to establish combat-related PTSD diagnostic status, extent of PTSD-related symptomatic distress, and presence of dissociative symptoms during their most stressful combat-related experiences. Extreme subgroups of veterans with current PTSD were classified as either low dissociators (N = 118) or high dissociators (N = 256) based on an abbreviated version of the Peritraumatic Dissociative Experiences Questionnaire. Dependent variables reflected subjective distress along with heart rate, skin conductance, electromyographic, and blood pressure data when responding to neutral and trauma-related audiovisual and imagery presentations. Veterans in the current PTSD group had significantly higher dissociation scores than did veterans in the lifetime and never PTSD groups. Among veterans with current PTSD, high dissociators reported greater PTSD-related symptomatic distress than did low dissociators, but the groups did not differ with respect to physiological reactivity to the trauma-related laboratory presentations. Our results replicate the previously reported relationship between peritraumatic dissociation and PTSD status in Vietnam combat veterans. However, we found no association between peritraumatic dissociation and the extent of physiological responding to trauma-relevant cues in male veterans with chronic combat-related PTSD.

  8. Strain- and age-dependent hippocampal neuron sodium currents correlate with epilepsy severity in Dravet syndrome mice.

    PubMed

    Mistry, Akshitkumar M; Thompson, Christopher H; Miller, Alison R; Vanoye, Carlos G; George, Alfred L; Kearney, Jennifer A

    2014-05-01

    Heterozygous loss-of-function SCN1A mutations cause Dravet syndrome, an epileptic encephalopathy of infancy that exhibits variable clinical severity. We utilized a heterozygous Scn1a knockout (Scn1a(+/-)) mouse model of Dravet syndrome to investigate the basis for phenotype variability. These animals exhibit strain-dependent seizure severity and survival. Scn1a(+/-) mice on strain 129S6/SvEvTac (129.Scn1a(+/-)) have no overt phenotype and normal survival compared with Scn1a(+/-) mice bred to C57BL/6J (F1.Scn1a(+/-)) that have severe epilepsy and premature lethality. We tested the hypothesis that strain differences in sodium current (INa) density in hippocampal neurons contribute to these divergent phenotypes. Whole-cell voltage-clamp recording was performed on acutely-dissociated hippocampal neurons from postnatal days 21-24 (P21-24) 129.Scn1a(+/-) or F1.Scn1a(+/-) mice and wild-type littermates. INa density was lower in GABAergic interneurons from F1.Scn1a(+/-) mice compared to wild-type littermates, while on the 129 strain there was no difference in GABAergic interneuron INa density between 129.Scn1a(+/-) mice and wild-type littermate controls. By contrast, INa density was elevated in pyramidal neurons from both 129.Scn1a(+/-) and F1.Scn1a(+/-) mice, and was correlated with more frequent spontaneous action potential firing in these neurons, as well as more sustained firing in F1.Scn1a(+/-) neurons. We also observed age-dependent differences in pyramidal neuron INa density between wild-type and Scn1a(+/-) animals. We conclude that preserved INa density in GABAergic interneurons contributes to the milder phenotype of 129.Scn1a(+/-) mice. Furthermore, elevated INa density in excitatory pyramidal neurons at P21-24 correlates with age-dependent onset of lethality in F1.Scn1a(+/-) mice. Our findings illustrate differences in hippocampal neurons that may underlie strain- and age-dependent phenotype severity in a Dravet syndrome mouse model, and emphasize a contribution

  9. Redox mechanism of S-nitrosothiol modulation of neuronal CaV3.2 T-type calcium channels.

    PubMed

    Lee, Jeonghan; Nelson, Michael T; Rose, Kirstin E; Todorovic, Slobodan M

    2013-10-01

    T-type calcium channels in the dorsal root ganglia (DRG) have a central function in tuning neuronal excitability and are implicated in sensory processing including pain. Previous studies have implicated redox agents in control of T-channel activity; however, the mechanisms involved are not completely understood. Here, we recorded T-type calcium currents from acutely dissociated DRG neurons from young rats and investigated the mechanisms of CaV3.2 T-type channel modulation by S-nitrosothiols (SNOs). We found that extracellular application of S-nitrosoglutathione (GSNO) and S-nitroso-N-acetyl-penicillamine rapidly reduced T-type current amplitudes. GSNO did not affect voltage dependence of steady-state inactivation and macroscopic current kinetics of T-type channels. The effects of GSNO were abolished by pretreatment of the cells with N-ethylmaleimide, an irreversible alkylating agent, but not by pretreatment with 1H-(1,2,4) oxadiazolo (4,3-a) quinoxalin-1-one, a specific soluble guanylyl cyclase inhibitor, suggesting a potential effect of GSNO on putative extracellular thiol residues on T-type channels. Expression of wild-type CaV3.2 channels or a quadruple Cys-Ala mutant in human embryonic kidney cells revealed that Cys residues in repeats I and II on the extracellular face of the channel were required for channel inhibition by GSNO. We propose that SNO-related molecules in vivo may lead to alterations of T-type channel-dependent neuronal excitability in sensory neurons and in the central nervous system in both physiological and pathological conditions such as neuronal ischemia/hypoxia.

  10. Ethanol exposure in early adolescence inhibits intrinsic neuronal plasticity via sigma-1 receptor activation in hippocampal CA1 neurons

    PubMed Central

    Sabeti, Jilla

    2011-01-01

    Background We demonstrated previously that rats exposed to chronic intermittent ethanol (CIE) vapors in early adolescence show increased magnitudes of long-term potentiation (LTP) of excitatory transmission when recorded at dendritic synapses in hippocampus. Large amplitude LTP following CIE exposure is mediated by sigma-1 receptors; however, not yet addressed is the role of sigma-1 receptors in modulating the intrinsic properties of neurons to alter their action potential firing during LTP. Methods Activity-induced plasticity of spike firing was investigated using rat hippocampal slice recordings to measure changes in both field excitatory postsynaptic potentials (fEPSPs) and population spikes (pop. spikes) concomitantly at dendritic inputs and soma of CA1 pyramidal neurons, respectively. Results We observed unique modifications in plasticity of action potential firing in hippocampal slices from CIE exposed adolescent rats, where the induction of large amplitude LTP by 100 Hz stimulations was accompanied by reduced CA1 neuronal excitability—reflected as decreased pop. spike efficacy and impaired activity-induced fEPSP-to-spike (E-S) potentiation. By contrast, LTP induction in ethanol-naïve control slices resulted in increased spike efficacy and robust E-S potentiation. E-S potentiation impairments emerged at 24 hr after CIE treatment cessation, but not before the alcohol withdrawal period, and were restored with bath-application of the sigma-1 receptor selective antagonist BD1047, but not the NMDA receptor antagonist D-AP5. Further evidence revealed a significantly shortened somatic fEPSP time course in adolescent CIE-withdrawn hippocampal slices during LTP; however, paired-pulse data show no apparent correspondence between E-S dissociation and altered recurrent feedback inhibition. Conclusions Results here suggest that acute withdrawal from adolescent CIE exposure triggers sigma-1 receptors that act to depress the efficacy of excitatory inputs in triggering

  11. Dissociation in families experiencing Intimate partner violence.

    PubMed

    Miller, Alison

    2017-02-16

    This paper, using an illustrative case study, presents the hypothesis that cyclical spouse abusers suffer from a dissociative condition (or perhaps a personality disorder in which dissociation is a prominent feature) that results from disorganized attachment. The partner of the spouse abuser tries various unsuccessful strategies to appease her spouse in order to change his behavior. If the relationship lasts for years, she adapts by developing a milder but parallel dissociative process, developing chains of state-dependent memory and resultant ego states for the different phases of the domestic abuse cycle. The children suffer from attachment disruption which can potentially continue the process to the next generation.

  12. Products of Dissociative Recombination in the Ionosphere

    NASA Technical Reports Server (NTRS)

    Cosby, Philip

    1996-01-01

    SRI International undertook a novel experimental measurement of the product states formed by dissociative ro-combination (DR) of C2(+), NO(+), and N2(+) as a function of both electron energy and reactant ion vibrational level. For these measurements we used a recently developed experimental technique for measuring dissociation product distributions that allows both the branching ratios to be accurately determined and the electronic and ro-vibrational state composition of the reactant ions to be specified. DR is the dominant electron loss mechanism in all regions of the ionosphere. In this process, electron attachment to the molecular ion produces an unstable neutral molecule that rapidly dissociates.

  13. Wavepacket theory of collisional dissociation in molecules

    SciTech Connect

    Kulander, K.

    1980-01-01

    An explicit integration scheme is used to solve the time dependent Schroedinger equation for wavepackets which model collisions in the collinear H + H/sub 2/ system. A realistic LEPS-type potential energy surface is used. Collision energies considered are above the dissociation threshold and probabilities for collision induced dissociation are reported. Also quantum mechanical state-to-state transition probabilities are generated. These results are compared to extensive classical trajectory calculations performed on this same system. The time evolution of the wavepacket densities is studied to understand the dynamics of the collinear collisional dissociation process.

  14. Direct simulation with vibration-dissociation coupling

    NASA Technical Reports Server (NTRS)

    Hash, David B.; Hassan, H. A.

    1992-01-01

    The majority of implementations of the Direct Simulation Monte Carlo (DSMC) method of Bird do not account for vibration-dissociation coupling. Haas and Boyd have proposed the vibrationally-favored dissociation model to accomplish this task. This model requires measurements of induction distance to determine model constants. A more general expression has been derived that does not require any experimental input. The model is used to calculate one-dimensional shock waves in nitrogen and the flow past a lunar transfer vehicle (LTV). For the conditions considered in the simulation, the influence of vibration-dissociation coupling on heat transfer in the stagnation region of the LTV can be significant.

  15. Dissociative Ionization of Pyridine by Electron Impact

    NASA Technical Reports Server (NTRS)

    Dateo, Christopher; Huo, Winifred; Kwak, Dochan (Technical Monitor)

    2002-01-01

    In order to understand the damage of biomolecules by electrons, a process important in radiation damage, we undertake a study of the dissociative ionization (DI) of pyridine (C5H5N) from the low-lying ionization channels. The methodology used is the same as in the benzene study. While no experimental DI data are available, we compare the dissociation products from our calculations with the dissociative photoionization measurements of Tixier et al. using dipole (e, e(+) ion) coincidence spectroscopy. Comparisons with the DI of benzene is also made so as to understand the difference in DI between a heterocyclic and an aromatic molecule.

  16. Dissociative identity disorder: a controversial diagnosis.

    PubMed

    Gillig, Paulette Marie

    2009-03-01

    A brief description of the controversies surrounding the diagnosis of dissociative identity disorder is presented, followed by a discussion of the proposed similarities and differences between dissociative identity disorder and borderline personality disorder. The phenomenon of autohypnosis in the context of early childhood sexual trauma and disordered attachment is discussed, as is the meaning of alters or alternate personalities. The author describes recent neurosciences research that may relate the symptoms of dissociative identity disorder to demonstrable disordered attention and memory processes. A clinical description of a typical patient presentation is included, plus some recommendations for approaches to treatment.

  17. Theory of dissociative tunneling ionization

    NASA Astrophysics Data System (ADS)

    Svensmark, Jens; Tolstikhin, Oleg I.; Madsen, Lars Bojer

    2016-05-01

    We present a theoretical study of the dissociative tunneling ionization process. Analytic expressions for the nuclear kinetic energy distribution of the ionization rates are derived. A particularly simple expression for the spectrum is found by using the Born-Oppenheimer (BO) approximation in conjunction with the reflection principle. These spectra are compared to exact non-BO ab initio spectra obtained through model calculations with a quantum mechanical treatment of both the electronic and nuclear degrees of freedom. In the regime where the BO approximation is applicable, imaging of the BO nuclear wave function is demonstrated to be possible through reverse use of the reflection principle, when accounting appropriately for the electronic ionization rate. A qualitative difference between the exact and BO wave functions in the asymptotic region of large electronic distances is shown. Additionally, the behavior of the wave function across the turning line is seen to be reminiscent of light refraction. For weak fields, where the BO approximation does not apply, the weak-field asymptotic theory describes the spectrum accurately.

  18. Neuronal Survival, Morphology and Outgrowth of Spiral Ganglion Neurons Using a Defined Growth Factor Combination

    PubMed Central

    Schwieger, Jana; Warnecke, Athanasia; Lenarz, Thomas; Esser, Karl-Heinz; Scheper, Verena

    2015-01-01

    Objectives The functionality of cochlear implants (CI) depends, among others, on the number and excitability of surviving spiral ganglion neurons (SGN). The spatial separation between the SGN, located in the bony axis of the inner ear, and the CI, which is inserted in the scala tympani, results in suboptimal performance of CI patients and may be decreased by attracting the SGN neurites towards the electrode contacts. Neurotrophic factors (NTFs) can support neuronal survival and neurite outgrowth. Methods Since brain-derived neurotrophic factor (BDNF) is well known for its neuroprotective effect and ciliary neurotrophic factor (CNTF) increases neurite outgrowth, we evaluated if the combination of BDNF and CNTF leads to an enhanced neuronal survival with extended neurite outgrowth. Both NTFs were added in effective high concentrations (BDNF 50ng/ml, CNTF 100ng/ml), alone and in combination, to cultured dissociated SGN of neonatal rats for 48 hours. Results The neuronal survival and neurite outgrowth were significantly higher in SGN treated with the combination of the two NTFs compared to treatment with each factor alone. Additionally, with respect to the morphology, the combination of BDNF and CNTF leads to a significantly higher number of bipolar neurons and a decreased number of neurons without neurites in culture. Conclusion The combination of BDNF and CNTF shows a great potential to increase the neuronal survival and the number of bipolar neurons in vitro and to regenerate retracted nerve fibers. PMID:26263175

  19. Some Rat Sensory Neurons in Culture Express Characteristics of Differentiated Pain Sensory Cells

    NASA Astrophysics Data System (ADS)

    Baccaglini, Paola I.; Hogan, Patrick G.

    1983-01-01

    Sensory neurons were dissociated from trigeminal ganglia or from dorsal root ganglia of rats, grown in culture, and examined for expression of properties of pain sensory cells. Many sensory neurons in culture are excited by low concentrations of capsaicin, reportedly a selective stimulus for pain sensory neurons. Many are excited by bradykinin, sensitized by prostaglandin E2, or specifically stained by an antiserum against substance P. These experiments provide a basis for the study of pain mechanisms in cell culture.

  20. Non-dissociative and dissociative ionization of a CO+ beam in intense ultrashort laser pulses

    NASA Astrophysics Data System (ADS)

    Gaire, B.; Ablikim, U.; Zohrabi, M.; Roland, S.; Carnes, K. D.; Ben-Itzhak, I.

    2011-05-01

    We have investigated the ionization of CO+ beams in intense ultrashort laser pulses. With the recent upgrades to our coincidence three-dimensional momentum imaging method we are able to measure both non-dissociative and dissociative ionization of the molecular-ion beam targets. Using CO+ as an example, we have found that non-dissociative ionization (leading to the metastable dication CO2+) involves a direct transition, i.e. the molecule is ionized with little or no internuclear distance stretch. Dissociative ionization (C+ + O+) occurs both directly and indirectly, stretching first and then ionizing. Our results show that the yield of dissociative ionization is higher than that of non-dissociative ionization and can be manipulated with the laser pulse duration by suppressing the indirect ionization path using ultrashort pulses (<=10 fs). Supported by the Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy.

  1. A review of dissociative disorders treatment studies.

    PubMed

    Brand, Bethany L; Classen, Catherine C; McNary, Scot W; Zaveri, Parin

    2009-09-01

    This review examines empirical reports of treatment for Dissociative Disorders (DD), including 16 DD treatment outcome studies and 4 case studies that used standardized measures. Collectively, these reports suggest that treatment for DD is associated with decreased symptoms of dissociation, depression, posttraumatic stress disorder, distress, and suicidality. Effect sizes, based on pre/post measures, are in the medium to large range across studies. Patients with dissociative disorder who integrated their dissociated self states were found to have reduced symptomatology compared with those who did not integrate. The magnitude of pre/post effect sizes for these DD studies are comparable to pre/post effect sizes in treatment studies of complex PTSD. There are significant methodological limitations in the current DD treatment outcome literature that reduce internal and external validity including regression towards the mean, limited sample sizes, and nonrandomized research designs. Implications for future research and treatment planning for patients suffering from DD are discussed.

  2. Collision-induced gas phase dissociation rates

    NASA Technical Reports Server (NTRS)

    Hansen, C. Frederick

    1990-01-01

    The Landau-Zener theory of reactive cross sections was applied to diatomic molecules dissociating from a ladder of vibrational states. The result predicts a dissociation rate that is quite well duplicated by an Arrhenius function having a preexponential temperature dependence of about T(sub -1/2), at least for inert collision partners. This relation fits experimental data reasonably well. The theory is then used to calculate the effect of vibrational nonequilibrium on dissociation rate. For Morse oscillators, the results are about the same as given by Hammerling, Kivel, and Teare in their analytic approximation for harmonic oscillators, though at very high temperature a correction for the partition function limit is included. The empirical correction for vibration nonequilibrium proposed by Park, which is a convenient algorithm for CFD calculations, is modified to prevent a drastic underestimation of dissociation rates that occurs with this method when vibrational temperature is much smaller than the kinetic temperature of the gas.

  3. ION PAIR DISSOCIATION: Spectroscopy and Dynamics

    NASA Astrophysics Data System (ADS)

    Suits, Arthur G.; Hepburn, John W.

    2006-05-01

    Ion pair dissociation processes may be studied using coherent vacuum ultraviolet laser sources in a manner entirely analogous to photoelectron spectroscopy, albeit with the anion playing the role of a heavy electron. If the excitation energy is above the dissociation energy and the kinetic energy of the fragment is measured using ion imaging, this approach is termed ion pair imaging spectroscopy (IPIS) and is related to conventional photoelectron spectroscopy. If the excitation energy is just below the dissociation energy and pulsed-field dissociation is employed, this approach is analogous to mass analyzed threshold ionization (MATI) spectroscopy and is termed threshold ion pair production spectroscopy (TIPPS). These approaches provide a novel means of investigating ion thermochemistry and spectroscopy and superexcited state decay dynamics at high resolution.

  4. A combined Bodian-Nissl stain for improved network analysis in neuronal cell culture.

    PubMed

    Hightower, M; Gross, G W

    1985-11-01

    Bodian and Nissl procedures were combined to stain dissociated mouse spinal cord cells cultured on coverslips. The Bodian technique stains fine neuronal processes in great detail as well as an intracellular fibrillar network concentrated around the nucleus and in proximal neurites. The Nissl stain clearly delimits neuronal cytoplasm in somata and in large dendrites. A combination of these techniques allows the simultaneous depiction of neuronal perikarya and all afferent and efferent processes. Costaining with little background staining by either procedure suggests high specificity for neurons. This procedure could be exploited for routine network analysis of cultured neurons.

  5. Paranormal belief and proneness to dissociation.

    PubMed

    Irwin, H J

    1994-12-01

    The study investigated the relationship between scores on paranormal belief and proneness to dissociation in a sample of 100 Australian students of psychology. Scores on dissociation were positively correlated with those on global paranormal belief and with belief in psi, precognition, spiritualism, and extraordinary life-forms. It is suggested that in some instances paranormal beliefs may be a component of a complex defensive framework constructed in the face of the perceived uncontrollability of life.

  6. Dissociation energy of molecules in dense gases

    NASA Technical Reports Server (NTRS)

    Kunc, J. A.

    1992-01-01

    A general approach is presented for calculating the reduction of the dissociation energy of diatomic molecules immersed in a dense (n = less than 10 exp 22/cu cm) gas of molecules and atoms. The dissociation energy of a molecule in a dense gas differs from that of the molecule in vacuum because the intermolecular forces change the intramolecular dynamics of the molecule, and, consequently, the energy of the molecular bond.

  7. Dissociation energies of PH and PH+.

    NASA Astrophysics Data System (ADS)

    Reddy, R. R.; Nazeer Ahammed, Y.; Srinivasa Rao, A.; Rao, T. V. R.

    1995-12-01

    Dissociation energies for the ground electronic states of diatomic PH and PH+ are determined by fitting empirical potential functions to the respective RKRV curves using correlation coefficients. The estimated ground state dissociation energies of PH and PH+ are 3.10 and 3.20 eV respectively by the curve fitting procedure using the Lippincott potential function. The computed values are in good agreement with experimental values.

  8. Sociodemographic profile of normal EEG-dissociative disorder (convulsion) patients.

    PubMed

    Chattopadhyay, P; Ghosh, S; Nayak, A; Das, P; Bandyopadhyay, A

    2009-08-01

    Few Indian studies have explored the sociodemographic variables of dissociative disorder (convulsion), which may be dramatic in presentation causing significant socio-economical and emotional difficulties to patients and care-givers. This prospective study hopes to explore the sociodemographic variables in normal EEG-disssociative disorder (convulsion). The study was conducted from January 2004 to September 2004 in the psychiatry outpatients department (OPD) of Nil Ratan Sircar Medical College and Hospital, Kolkata. After screening by history, astute clinical examination and application of predetermined inclusion and exclusion criterion, 41/52 patients were finally selected for the study. Written consent was taken from all the patients. They were then evaluated to elicit necessary information required in the semistructured proforma. Data were analysed by using appropriate statistical method ie, Z-test. The present study suggested that dissociative disorder (convulsion) predominantly affected females, mostly housewives and students, coming from rural, low socio-economic conditions with poor educational background. Majority of the patients presented acutely. Depressive disorder was the most common comorbid psychiatric abnormality. The findings of the present study were in tune with the findings of the few earlier studies available.

  9. A Neurogenetic Dissociation between Punishment-, Reward-, and Relief-Learning in Drosophila

    PubMed Central

    Yarali, Ayse; Gerber, Bertram

    2010-01-01

    What is particularly worth remembering about a traumatic experience is what brought it about, and what made it cease. For example, fruit flies avoid an odor which during training had preceded electric shock punishment; on the other hand, if the odor had followed shock during training, it is later on approached as a signal for the relieving end of shock. We provide a neurogenetic analysis of such relief learning. Blocking, using UAS-shibirets1, the output from a particular set of dopaminergic neurons defined by the TH-Gal4 driver partially impaired punishment learning, but left relief learning intact. Thus, with respect to these particular neurons, relief learning differs from punishment learning. Targeting another set of dopaminergic/serotonergic neurons defined by the DDC-Gal4 driver on the other hand affected neither punishment nor relief learning. As for the octopaminergic system, the tbhM18 mutation, compromising octopamine biosynthesis, partially impaired sugar-reward learning, but not relief learning. Thus, with respect to this particular mutation, relief learning, and reward learning are dissociated. Finally, blocking output from the set of octopaminergic/tyraminergic neurons defined by the TDC2-Gal4 driver affected neither reward, nor relief learning. We conclude that regarding the used genetic tools, relief learning is neurogenetically dissociated from both punishment and reward learning. This may be a message relevant also for analyses of relief learning in other experimental systems including man. PMID:21206762

  10. Dissociative Ionization of Benzene by Electron Impact

    NASA Technical Reports Server (NTRS)

    Huo, Winifred; Dateo, Christopher; Kwak, Dochan (Technical Monitor)

    2002-01-01

    We report a theoretical study of the dissociative ionization (DI) of benzene from the low-lying ionization channels. Our approach makes use of the fact that electron motion is much faster than nuclear motion and DI is treated as a two-step process. The first step is electron-impact ionization resulting in an ion with the same nuclear geometry as the neutral molecule. In the second step the nuclei relax from the initial geometry and undergo unimolecular dissociation. For the ionization process we use the improved binary-encounter dipole (iBED) model. For the unimolecular dissociation step, we study the steepest descent reaction path to the minimum of the ion potential energy surface. The path is used to analyze the probability of unimolecular dissociation and to determine the product distributions. Our analysis of the dissociation products and the thresholds of the productions are compared with the result dissociative photoionization measurements of Feng et al. The partial oscillator strengths from Feng et al. are then used in the iBED cross section calculations.

  11. Resurgent Na+ current in pyramidal neurones of rat perirhinal cortex: axonal location of channels and contribution to depolarizing drive during repetitive firing

    PubMed Central

    Castelli, Loretta; Biella, Gerardo; Toselli, Mauro; Magistretti, Jacopo

    2007-01-01

    The perirhinal cortex (PRC) is a supra-modal cortical area that collects and integrates information originating from uni- and multi-modal neocortical regions and directed to the hippocampus. The mechanisms that underlie the specific excitable properties of the different PRC neuronal types are still largely unknown, and their elucidation may be important in understanding the integrative functions of PRC. In this study we investigated the expression and properties of resurgent Na+ current (INaR) in pyramidal neurones of rat PRC area 35 (layer II). Patch-clamp experiments in acute PRC slices were first carried out. A measurable INaR was expressed by a large majority of neurones (31 out of 35 cells). INaR appeared as an inward, slowly decaying current elicited upon step repolarization after depolarizations sufficient to induce nearly complete inactivation of the transient Na+ current (INaT). INaR had a peak amplitude of ∼2.5% that of INaT, and showed the typical biophysical properties also observed in other neuronal types (i.e. cerebellar Purkinje and granule cells), including a bell-shaped current–voltage relationship with a peak at approximately −40 mV, and a characteristic acceleration of activation and decay speed at potentials negative to −45 mV. Current-clamp experiments were then carried out in which repetitive action-potential discharge at various frequencies was induced with depolarizing current injection. The voltage signals thus obtained were then used as command waveforms for voltage-clamp recordings. These experiments showed that a Na+ current identifiable as INaR activates in the early interspike phase even at relatively high firing frequencies (20 Hz), thereby contributing to the depolarizing drive and possibly enhancing repetitive discharge. In acutely dissociated area 35 layer II neurones, as well as in nucleated patches from the same neurones, INaR was never observed, despite the presence of typical INaTs. Since in both preparations neuronal

  12. Dissociation and borderline personality disorder: an update for clinicians.

    PubMed

    Korzekwa, Marilyn I; Dell, Paul F; Pain, Clare

    2009-02-01

    Dissociation occurs in about two thirds of people with borderline personality disorder (BPD) but is still not well understood by clinicians. In the past decade, however, research has used new measures of dissociation that provide some of the detail that clinicians need to understand and treat the dissociative symptoms of patients with BPD. In particular, this review examines BPD's comorbidity with the dissociative disorders, the neurobiology of dissociation in BPD, the role of trauma and disorganized attachment in the etiology of dissociation in BPD, and the clinical assessment and treatment of dissociation in BPD.

  13. [Acute muscle weakness: differential diagnoses].

    PubMed

    Antoniuk, Sérgio A

    2013-09-06

    Acute muscle weakness, a common disorder in pediatrics, can occur from impairment of any part of the motor unit, including the upper motor neuron, lower motor neuron, peripheral nerve, neuromuscular junction or muscle. It usually manifests itself as an acute or hyperacute motor disorder of progressive or rapidly progressive course. Acute muscle weakness is a neuromuscular emergency, especially if it affects the respiratory or oropharyngeal musculature. The location of the motor weakness and associated neurological signs and symptoms usually indicate the location of the lesion. The onset, speed and clinical evolution, as well as other data from the patient's history, suggest the pathophysiological differential diagnosis. Successful treatment depends on the immediate and correct differential diagnosis. This paper presents the main differential diagnosis of main neuromuscular diseases that cause acute muscle weakness in children.

  14. Kv4 Channels Underlie the Subthreshold-Operating A-type K-current in Nociceptive Dorsal Root Ganglion Neurons.

    PubMed

    Phuket, Thanawath Ratanadilok Na; Covarrubias, Manuel

    2009-01-01

    The dorsal root ganglion (DRG) contains heterogeneous populations of sensory neurons including primary nociceptive neurons and C-fibers implicated in pain signaling. Recent studies have demonstrated DRG hyperexcitability associated with downregulation of A-type K(+) channels; however, the molecular correlate of the corresponding A-type K(+) current (I(A)) has remained hypothetical. Kv4 channels may underlie the I(A) in DRG neurons. We combined electrophysiology, molecular biology (Whole-Tissue and Single-Cell RT-PCR) and immunohistochemistry to investigate the molecular basis of the I(A) in acutely dissociated DRG neurons from 7- to 8-day-old rats. Whole-cell recordings demonstrate a robust tetraethylammonium-resistant (20 mM) and 4-aminopyridine-sensitive (5 mM) I(A). Matching Kv4 channel properties, activation and inactivation of this I(A) occur in the subthreshold range of membrane potentials and the rate of recovery from inactivation is rapid and voltage-dependent. Among Kv4 transcripts, the DRG expresses significant levels of Kv4.1 and Kv4.3 mRNAs. Also, single small-medium diameter DRG neurons ( approximately 30 mum) exhibit correlated frequent expression of mRNAs encoding Kv4.1 and Nav1.8, a known nociceptor marker. In contrast, the expressions of Kv1.4 and Kv4.2 mRNAs at the whole-tissue and single-cell levels are relatively low and infrequent. Kv4 protein expression in nociceptive DRG neurons was confirmed by immunohistochemistry, which demonstrates colocalization of Kv4.3 and Nav1.8, and negligible expression of Kv4.2. Furthermore, specific dominant-negative suppression and overexpression strategies confirmed the contribution of Kv4 channels to I(A) in DRG neurons. Contrasting the expression patterns of Kv4 channels in the central and peripheral nervous systems, we discuss possible functional roles of these channels in primary sensory neurons.

  15. Dissociations between developmental dyslexias and attention deficits

    PubMed Central

    Lukov, Limor; Friedmann, Naama; Shalev, Lilach; Khentov-Kraus, Lilach; Shalev, Nir; Lorber, Rakefet; Guggenheim, Revital

    2014-01-01

    We examine whether attention deficits underlie developmental dyslexia, or certain types of dyslexia, by presenting double dissociations between the two. We took into account the existence of distinct types of dyslexia and of attention deficits, and focused on dyslexias that may be thought to have an attentional basis: letter position dyslexia (LPD), in which letters migrate within words, attentional dyslexia (AD), in which letters migrate between words, neglect dyslexia, in which letters on one side of the word are omitted or substituted, and surface dyslexia, in which words are read via the sublexical route. We tested 110 children and adults with developmental dyslexia and/or attention deficits, using extensive batteries of reading and attention. For each participant, the existence of dyslexia and the dyslexia type were tested using reading tests that included stimuli sensitive to the various dyslexia types. Attention deficit and its type was established through attention tasks assessing sustained, selective, orienting, and executive attention functioning. Using this procedure, we identified 55 participants who showed a double dissociation between reading and attention: 28 had dyslexia with normal attention and 27 had attention deficits with normal reading. Importantly, each dyslexia with suspected attentional basis dissociated from attention: we found 21 individuals with LPD, 13 AD, 2 neglect dyslexia, and 12 surface dyslexia without attention deficits. Other dyslexia types (vowel dyslexia, phonological dyslexia, visual dyslexia) also dissociated from attention deficits. Examination of 55 additional individuals with both a specific dyslexia and a certain attention deficit found no attention function that was consistently linked with any dyslexia type. Specifically, LPD and AD dissociated from selective attention, neglect dyslexia dissociated from orienting, and surface dyslexia dissociated from sustained and executive attention. These results indicate that

  16. Dissociations between developmental dyslexias and attention deficits.

    PubMed

    Lukov, Limor; Friedmann, Naama; Shalev, Lilach; Khentov-Kraus, Lilach; Shalev, Nir; Lorber, Rakefet; Guggenheim, Revital

    2014-01-01

    We examine whether attention deficits underlie developmental dyslexia, or certain types of dyslexia, by presenting double dissociations between the two. We took into account the existence of distinct types of dyslexia and of attention deficits, and focused on dyslexias that may be thought to have an attentional basis: letter position dyslexia (LPD), in which letters migrate within words, attentional dyslexia (AD), in which letters migrate between words, neglect dyslexia, in which letters on one side of the word are omitted or substituted, and surface dyslexia, in which words are read via the sublexical route. We tested 110 children and adults with developmental dyslexia and/or attention deficits, using extensive batteries of reading and attention. For each participant, the existence of dyslexia and the dyslexia type were tested using reading tests that included stimuli sensitive to the various dyslexia types. Attention deficit and its type was established through attention tasks assessing sustained, selective, orienting, and executive attention functioning. Using this procedure, we identified 55 participants who showed a double dissociation between reading and attention: 28 had dyslexia with normal attention and 27 had attention deficits with normal reading. Importantly, each dyslexia with suspected attentional basis dissociated from attention: we found 21 individuals with LPD, 13 AD, 2 neglect dyslexia, and 12 surface dyslexia without attention deficits. Other dyslexia types (vowel dyslexia, phonological dyslexia, visual dyslexia) also dissociated from attention deficits. Examination of 55 additional individuals with both a specific dyslexia and a certain attention deficit found no attention function that was consistently linked with any dyslexia type. Specifically, LPD and AD dissociated from selective attention, neglect dyslexia dissociated from orienting, and surface dyslexia dissociated from sustained and executive attention. These results indicate that

  17. Agonist action of taurine on glycine receptors in rat supraoptic magnocellular neurones: possible role in osmoregulation.

    PubMed

    Hussy, N; Deleuze, C; Pantaloni, A; Desarménien, M G; Moos, F

    1997-08-01

    1. To evaluate the implication of taurine in the physiology of supraoptic neurones, we (i) investigated the agonist properties of taurine on glycine and GABAA receptors of supraoptic magnocellular neurones acutely dissociated from adult rats, using whole-cell voltage clamp, (ii) studied the effects of taurine and strychnine in vivo by extracellular recordings of supraoptic vasopressin neurones in anaesthetized rats, and (iii) measured the osmolarity-dependent release of endogenous taurine from isolated supraoptic nuclei by HPLC. 2. GABA, glycine and taurine evoked rapidly activating currents that all reversed close to the equilibrium potential for Cl-, indicating activation of Cl(-)-selective channels. Glycine-activated currents were reversibly blocked by strychnine (IC50 of 35 nM with 100 microM glycine), but were unaffected by the GABAA antagonist gabazine (1-3 microM). GABA-activated currents were reversibly antagonized by 3 microM gabazine, but not by strychnine (up to 1 microM). 3. Responses to 1 mM taurine were blocked by strychnine but not by gabazine and showed no additivity with glycine-induced currents, indicating selective activation of glycine receptors. Responses to 10 mM taurine were partially antagonized by gabazine, the residual current being blocked by strychnine. Thus, taurine is also a weak agonist of GABAA receptors. 4. In the presence of gabazine, taurine activated glycine receptors with an EC50 of 406 microM. Taurine activated at most 70% of maximal glycine currents, suggesting that it is a partial agonist of glycine receptors. 5. In vivo, locally applied strychnine (300 nM) increased and taurine (1 mM) decreased the basal electrical activity of vasopressin neurones in normally hydrated rats. The effect of strychnine was markedly more pronounced in water-loaded rats. 6. Taurine, which is concentrated in supraoptic glial cells, could be released from isolated supraoptic nuclei upon hyposmotic stimulation. Decreases in osmolarity of 15 and 30

  18. Dissociative experiences in epilepsy: effects of epilepsy-related factors on pathological dissociation.

    PubMed

    Hara, Koichiro; Adachi, Naoto; Akanuma, Nozomi; Ito, Masumi; Okazaki, Mitsutoshi; Matsubara, Ryoji; Adachi, Takuya; Ishii, Ryouhei; Kanemoto, Kousuke; Matsuura, Masato; Hara, Eriko; Kato, Masaaki; Onuma, Teiichi

    2015-03-01

    Psychogenic nonepileptic seizures (PNESs) in patients with epilepsy can be categorized as dissociative disorders. The prevalence of PNESs in patients with epilepsy appears to be much higher than that of dissociative experiences in nonclinical subjects. In order to clarify as to whether epilepsy-related factors were associated with pathological dissociation, we conducted a controlled study with 225 patients with epilepsy and 334 nonclinically matched individuals. All participants completed the Japanese version of the Dissociative Experiences Scale (DES). There was no significant difference in the DES score (DES-S) between the group with epilepsy and the control group. The group with epilepsy showed a significantly higher DES taxon (DES-T; a subset of DES-S and an index of pathological dissociation) than the control group. Thirty-one out of the 225 patients with epilepsy (13.8%) had PNESs. Because of its strong association with the DES-S and DES-T, PNESs can be regarded as a symptom of dissociation. With multiple regression analysis, the patients with a shorter duration of epilepsy, higher seizure frequency, or shorter period in education tend to suffer from pathological dissociation. These findings demonstrate that patients with epilepsy are more prone to experiencing pathological dissociation when having certain clinical factors.

  19. Is the dissociative adult suggestible? A test of the trauma and fantasy models of dissociation.

    PubMed

    Kluemper, Nicole S; Dalenberg, Constance

    2014-01-01

    Psychologists have long assumed a connection between traumatic experience and psychological dissociation. This hypothesis is referred to as the trauma model of dissociation. In the past decade, a series of papers have been published that question this traditional causal link, proposing an alternative fantasy model of dissociation. In the present research, the relationship among dissociation, suggestibility, and fantasy proneness was examined. Suggestibility was measured through the Gudjonsson Scale of Interrogative Suggestibility (GSS) as well as an autobiographically based version of this measure based on the events of September 11, 2001. Consistent with prior research and with the trauma model, dissociation correlated positively with trauma severity (r = .32, p < .01) and fantasy proneness (r = .60, p < .01). Inconsistent with the fantasy model, dissociation did not correlate with the neutral form of the GSS and correlated negatively (r = -.24, p < .05) with the trauma-focused form of this suggestibility measure. Although some participants did become quite emotional during the procedure, the risk/benefit ratio was perceived by almost all participants to be positive, with more reactive individuals evaluating the procedure more positively. The results consistently support the trauma model of dissociation and fail to support the fantasy model of dissociation.

  20. Dissociation in borderline personality disorder: a detailed look.

    PubMed

    Korzekwa, Marilyn I; Dell, Paul F; Links, Paul S; Thabane, Lehana; Fougere, Philip

    2009-01-01

    The objective of the present study was to assess in detail the whole spectrum of normal and pathological dissociative experiences and dissociative disorder (DD) diagnoses in borderline personality disorder (BPD) as diagnosed with the Revised Diagnostic Interview for Borderlines. Dissociation was measured comprehensively in 21 BPD outpatients using the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised, the Multidimensional Inventory of Dissociation (MID), the Dissociative Experiences Scale pathological taxon analysis, and the Somatoform Dissociation Questionnaire. The frequencies of DDs in this BPD sample were as follows: 24% no DD, 29% mild DD (dissociative amnesia and depersonalization disorder), 24% DD Not Otherwise Specified (DDNOS), and 24% dissociative identity disorder. With regard to the dissociative experiences endorsed, almost all patients reported identity confusion, unexplained mood changes, and depersonalization. Even those BPD patients with mild DD reported derealization, depersonalization, and dissociative amnesia. BPD patients with DDNOS reported frequent depersonalization, frequent amnesia, and notable experiences of identity alteration. BPD patients with dissociative identity disorder endorsed severe dissociative symptoms in all categories. Analysis of the MID pathological dissociation items revealed that 32% of the items were endorsed at a clinically significant level of frequency by more than 50% of our BPD patients. In conclusion, the frequencies of Diagnostic and Statistical Manual of Mental Disorders (4th ed.) DDs in these patients with BPD were surprisingly high. Likewise, the "average" BPD patient endorsed a wide variety of recurrent pathological dissociative symptoms.

  1. Isotope separation by photoselective dissociative electron capture

    DOEpatents

    Stevens, Charles G. [Pleasanton, CA

    1978-08-29

    A method of separating isotopes based on photoselective electron capture dissociation of molecules having an electron capture cross section dependence on the vibrational state of the molecule. A molecular isotope source material is irradiated to selectively excite those molecules containing a desired isotope to a predetermined vibrational state having associated therewith an electron capture energy region substantially non-overlapping with the electron capture energy ranges associated with the lowest vibration states of the molecules. The isotope source is also subjected to electrons having an energy corresponding to the non-overlapping electron capture region whereby the selectively excited molecules preferentially capture electrons and dissociate into negative ions and neutrals. The desired isotope may be in the negative ion product or in the neutral product depending upon the mechanism of dissociation of the particular isotope source used. The dissociation product enriched in the desired isotope is then separated from the reaction system by conventional means. Specifically, .sup.235 UF.sub.6 is separated from a UF.sub.6 mixture by selective excitation followed by dissociative electron capture into .sup.235 UF.sub.5 - and F.

  2. Isotope separation by photoselective dissociative electron capture

    DOEpatents

    Stevens, C.G.

    1978-08-29

    Disclosed is a method of separating isotopes based on photoselective electron capture dissociation of molecules having an electron capture cross section dependence on the vibrational state of the molecule. A molecular isotope source material is irradiated to selectively excite those molecules containing a desired isotope to a predetermined vibrational state having associated therewith an electron capture energy region substantially non-overlapping with the electron capture energy ranges associated with the lowest vibration states of the molecules. The isotope source is also subjected to electrons having an energy corresponding to the non-overlapping electron capture region whereby the selectively excited molecules preferentially capture electrons and dissociate into negative ions and neutrals. The desired isotope may be in the negative ion product or in the neutral product depending upon the mechanism of dissociation of the particular isotope source used. The dissociation product enriched in the desired isotope is then separated from the reaction system by conventional means. Specifically, [sup 235]UF[sub 6] is separated from a UF[sub 6] mixture by selective excitation followed by dissociative electron capture into [sup 235]UF[sub 5]- and F. 2 figs.

  3. Ion-induced dissociation dynamics of acetylene

    SciTech Connect

    De, Sankar; Rajput, Jyoti; Roy, A.; Safvan, C. P.; Ghosh, P. N.

    2008-02-15

    We report on the results of dissociation dynamics of multiple charged acetylene molecules formed in collision with 1.2 MeV Ar{sup 8+} projectiles. Using the coincidence map, we can separate out the different dissociation pathways between carbon and hydrogen ionic fragments as well as complete two-body breakup events. From the measured slopes of the coincidence islands for carbon atomic fragments and theoretical values determined from the charge and momentum distribution of the correlated particles, we observe a diatom like behavior of the C-C charged complex during dissociation of multiply charged C{sub 2}H{sub 2}. We conclude that this behavior in breakup dynamics is a signature of sequentiality in dissociation of this multiply charged molecular species. The shape and orientation of the islands give further information about the momentum balance in the fragmentation process of two- or many-body dissociation pathways. Kinetic energy release of different breakup channels are reported here and compared with values calculated from the pure Coulomb explosion model.

  4. Presynaptic glycine receptors on GABAergic terminals facilitate discharge of dopaminergic neurons in ventral tegmental area.

    PubMed

    Ye, Jiang-Hong; Wang, Fushun; Krnjevic, Kresimir; Wang, Weizhen; Xiong, Zhi-Gang; Zhang, Jingli

    2004-10-13

    GABA-mediated postsynaptic currents (IPSCs) were recorded from dopaminergic (DA) neurons of the ventral tegmental area (VTA) of rats, in acute brain slices, and from enzymatically or mechanically dissociated neurons. In young rats (3-10 d of age), where GABA is excitatory, glycine (1-3 microm) and taurine (10-30 microm) increased the amplitude of evoked IPSCs (eIPSCs) and the frequency of spontaneous IPSCs (sIPSCs) but had minimal postsynaptic effects. Strychnine (1 microm) blocked the action of glycine; when applied alone, it reduced the amplitude of eIPSCs and the frequency of sIPSCs, indicating a tonic facilitation of GABAergic excitation by some endogenous glycine agonist(s). In medium containing no Ca2+, or with Cd2+ or tetrodotoxin added, the amplitude and especially the frequency of sIPSCs greatly diminished. In many cells, glycine had no effect on remaining miniature IPSCs, suggesting a preterminal site of glycine receptors (GlyRs). Fura-2 fluorescent imaging showed a glycine-induced increase of [Ca2+] in nerve terminals (on DA neurons), which was suppressed by strychnine or 3 microm omega-conotoxin MVIIA. Therefore, the presynaptic GlyR-mediated facilitation of GABAergic transmission seems to be mediated by N- and/or P/Q-type Ca2+ channels. In older rats (22-30 d of age), where GABA causes inhibition, the effect of strychnine on GABAergic IPSCs was reversed to facilitation, indicating a tonic glycinergic inhibition of GABA release. Furthermore, glycine (1-3 microm) reduced the amplitude of eIPSCs and the frequency of sIPSCs. Hence, the overall effect of the presynaptic action of glycine is to enhance the firing of DA cells, both in very young and older rats.

  5. Substance P suppresses GABAA receptor function via protein kinase C in primary sensory neurones of bullfrogs.

    PubMed Central

    Yamada, K; Akasu, T

    1996-01-01

    1. The effects of substance P (SP) and related tachykinins on the function of gamma-aminobutyric acid-A (GABAA) receptors were examined in acutely dissociated neurones of bullfrog dorsal root ganglia (DRG) by using whole-cell voltage-clamp techniques. 2. Application of SP (10 nM to 1 microM) depressed inward currents produced by GABAA receptor activation (IGABA). Neurokinin A (NKA) and neurokinin B (NKB) also depressed IGABA; the rank order of agonist potency was SP > NKA > NKB. Spantide ([D-Arg1, D-Trp7,9,Leu11]SP) and L-703,606, NK1 receptor antagonists, blocked the SP-induced depression of IGABA. 3. SP irreversibly depressed IGABA, when neurones were intracellularly dialysed with GTP gamma S. Intracellular application of GDP beta S prevented the SP-induced depression of IGABA. Pertussis toxin (PTX) did not block the inhibitory effect of SP on IGABA. 4. The depression of IGABA produced by SP was inhibited by H-7 and PKC(19-36), protein kinase C (PKC) inhibitors, but not by H-9 and HA-1004, protein kinase A inhibitors. IGABA was suppressed by application of sn-1,2-dioctanoyl glycerol (DOG), a PKC activator. 5. It is concluded that activation of neurokinin-1 (NK1) receptors downregulates the function of the GABAA receptor of primary sensory neurones through a PTX-insensitive G-protein. PKC may be involved in the transduction pathway of the tachykinin-induced inhibition of the GABAA receptor. PMID:8910228

  6. Modulation of action potential and calcium signaling by levetiracetam in rat sensory neurons.

    PubMed

    Ozcan, Mete; Ayar, Ahmet

    2012-06-01

    Levetiracetam (LEV), a new anticonvulsant agent primarily used to treat epilepsy, has been used in pain treatment but the cellular mechanism of this action remains unclear. This study aimed to investigate effects of LEV on the excitability and membrane depolarization-induced calcium signaling in isolated rat sensory neurons using the whole-cell patch clamp and fura 2-based ratiometric Ca(2+)-imaging techniques. Dorsal root ganglia (DRG) were excised from neonatal rats, and cultured following enzymatic and mechanical dissociation. Under current clamp conditions, acute application of LEV (30 µM, 100 µM and 300 µM) significantly increased input resistance and caused the membrane to hyperpolarize from resting membrane potential in a dose-dependent manner. Reversal potentials of action potential (AP) after hyperpolarising amplitudes were shifted to more negative, toward to potassium equilibrium potentials, after application of LEV. It also caused a decrease in number of APs in neurons fired multiple APs in response to prolonged depolarization. Fura-2 fluorescence Ca(2+) imaging protocols revealed that HiK(+) (30 mM)-induced intracellular free Ca(2+) ([Ca(2+)](i)) was inhibited to 97.8 ± 4.6% (n = 17), 92.6 ± 4.8% (n = 17, p < 0.01) and 89.1 ± 5.1% (n = 18, p < 0.01) after application of 30 µM, 100 µM and 300 µM LEV (respectively), without any significant effect on basal levels of [Ca(2+)](i). This is the first evidence for the effect of LEV on the excitability of rat sensory neurons through an effect which might involve activation of potassium channels and inhibition of entry of Ca(2+), providing new insights for cellular mechanism(s) of LEV in pain treatment modalities.

  7. Somatodendritic and excitatory postsynaptic distribution of neuron-type dystrophin isoform, Dp40, in hippocampal neurons.

    PubMed

    Fujimoto, Takahiro; Itoh, Kyoko; Yaoi, Takeshi; Fushiki, Shinji

    2014-09-12

    The Duchenne muscular dystrophy (DMD) gene produces multiple dystrophin (Dp) products due to the presence of several promoters. We previously reported the existence of a novel short isoform of Dp, Dp40, in adult mouse brain. However, the exact biochemical expression profile and cytological distribution of the Dp40 protein remain unknown. In this study, we generated a polyclonal antibody against the NH2-terminal region of the Dp40 and identified the expression profile of Dp40 in the mouse brain. Through an analysis using embryonic and postnatal mouse cerebrums, we found that Dp40 emerged from the early neonatal stages until adulthood, whereas Dp71, an another Dp short isoform, was highly detected in both prenatal and postnatal cerebrums. Intriguingly, relative expressions of Dp40 and Dp71 were prominent in cultured dissociated neurons and non-neuronal cells derived from mouse hippocampus, respectively. Furthermore, the immunocytological distribution of Dp40 was analyzed in dissociated cultured neurons, revealing that Dp40 is detected in the soma and its dendrites, but not in the axon. It is worthy to note that Dp40 is localized along the subplasmalemmal region of the dendritic shafts, as well as at excitatory postsynaptic sites. Thus, Dp40 was identified as a neuron-type Dp possibly involving dendritic and synaptic functions.

  8. Cystitis - acute

    MedlinePlus

    Uncomplicated urinary tract infection; UTI - acute cystitis; Acute bladder infection; Acute bacterial cystitis ... cause. Menopause also increases the risk for a urinary tract infection. The following also increase your chances of having ...

  9. Combined Changes in Chloride Regulation and Neuronal Excitability Enable Primary Afferent Depolarization to Elicit Spiking without Compromising its Inhibitory Effects

    PubMed Central

    2016-01-01

    The central terminals of primary afferent fibers experience depolarization upon activation of GABAA receptors (GABAAR) because their intracellular chloride concentration is maintained above electrochemical equilibrium. Primary afferent depolarization (PAD) normally mediates inhibition via sodium channel inactivation and shunting but can evoke spikes under certain conditions. Antidromic (centrifugal) conduction of these spikes may contribute to neurogenic inflammation while orthodromic (centripetal) conduction could contribute to pain in the case of nociceptive fibers. PAD-induced spiking is assumed to override presynaptic inhibition. Using computer simulations and dynamic clamp experiments, we sought to identify which biophysical changes are required to enable PAD-induced spiking and whether those changes necessarily compromise PAD-mediated inhibition. According to computational modeling, a depolarizing shift in GABA reversal potential (EGABA) and increased intrinsic excitability (manifest as altered spike initiation properties) were necessary for PAD-induced spiking, whereas increased GABAAR conductance density (ḡGABA) had mixed effects. We tested our predictions experimentally by using dynamic clamp to insert virtual GABAAR conductances with different EGABA and kinetics into acutely dissociated dorsal root ganglion (DRG) neuron somata. Comparable experiments in central axon terminals are prohibitively difficult but the biophysical requirements for PAD-induced spiking are arguably similar in soma and axon. Neurons from naïve (i.e. uninjured) rats were compared before and after pharmacological manipulation of intrinsic excitability, and against neurons from nerve-injured rats. Experimental data confirmed that, in most neurons, both predicted changes were necessary to yield PAD-induced spiking. Importantly, such changes did not prevent PAD from inhibiting other spiking or from blocking spike propagation. In fact, since the high value of ḡGABA required for PAD

  10. Dissociation in virtual reality: depersonalization and derealization

    NASA Astrophysics Data System (ADS)

    Garvey, Gregory P.

    2010-01-01

    This paper looks at virtual worlds such as Second Life7 (SL) as possible incubators of dissociation disorders as classified by the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition3 (also known as the DSM-IV). Depersonalization is where "a person feels that he or she has changed in some way or is somehow unreal." Derealization when "the same beliefs are held about one's surroundings." Dissociative Identity Disorder (DID), previously known as multiple personality disorder fits users of Second Life who adopt "in-world" avatars and in effect, enact multiple distinct identities or personalities (known as alter egos or alters). Select questions from the Structured Clinical Interview for Depersonalization (SCI-DER)8 will be discussed as they might apply to the user's experience in Second Life. Finally I would like to consider the hypothesis that rather than a pathological disorder, dissociation is a normal response to the "artificial reality" of Second Life.

  11. Psychotherapy and pharmacotherapy for patients with dissociative identity disorder.

    PubMed

    Gentile, Julie P; Dillon, Kristy S; Gillig, Paulette Marie

    2013-02-01

    There is a wide variety of what have been called "dissociative disorders," including dissociative amnesia, dissociative fugue, depersonalization disorder, dissociative identity disorder, and forms of dissociative disorder not otherwise specified. Some of these diagnoses, particularly dissociative identity disorder, are controversial and have been questioned by many clinicians over the years. The disorders may be under-diagnosed or misdiagnosed, but many persons who have experienced trauma report "dissociative" symptoms. Prevalence of dissociative disorders is unknown, but current estimates are higher than previously thought. This paper reviews clinical, phenomenological, and epidemiological data regarding diagnosis in general, and illustrates possible treatment interventions for dissociative identity disorder, with a focus on psychotherapy interventions and a review of current psychopharmacology recommendations as part of a comprehensive multidisciplinary treatment plan.

  12. Type and Timing of Childhood Maltreatment and Severity of Shutdown Dissociation in Patients with Schizophrenia Spectrum Disorder

    PubMed Central

    Schalinski, Inga; Teicher, Martin H.

    2015-01-01

    Dissociation, particularly the shutting down of sensory, motor and speech systems, has been proposed to emerge in susceptible individuals as a defensive response to traumatic stress. In contrast, other individuals show signs of hyperarousal to acute threat. A key question is whether exposure to particular types of stressful events during specific stages of development can program an individual to have a strong dissociative response to subsequent stressors. Vulnerability to ongoing shutdown dissociation was assessed in 75 inpatients (46M/29F, M = 31±10 years old) with schizophrenia spectrum disorder and related to number of traumatic events experienced or witnessed during childhood or adulthood. The Maltreatment and Abuse Chronology of Exposure (MACE) scale was used to collect retrospective recall of exposure to ten types of maltreatment during each year of childhood. Severity of shutdown dissociation was related to number of childhood but not adult traumatic events. Random forest regression with conditional trees indicated that type and timing of childhood maltreatment could predictably account for 31% of the variance (p < 0.003) in shutdown dissociation, with peak vulnerability occurring at 13-14 years of age and with exposure to emotional neglect followed by various forms of emotional abuse. These findings suggest that there may be windows of vulnerability to the development of shutdown dissociation. Results support the hypothesis that experienced events are more important than witnessed events, but challenge the hypothesis that “life-threatening” events are a critical determinant. PMID:25992568

  13. Blackbody Infrared Radiative Dissociation of Protonated Oligosaccharides

    NASA Astrophysics Data System (ADS)

    Fentabil, Messele A.; Daneshfar, Rambod; Kitova, Elena N.; Klassen, John S.

    2011-12-01

    The dissociation pathways, kinetics, and energetics of protonated oligosaccharides in the gas phase were investigated using blackbody infrared radiative dissociation (BIRD). Time-resolved BIRD measurements were performed on singly protonated ions of cellohexaose (Cel6), which is composed of β-(1 → 4)-linked glucopyranose rings, and five malto-oligosaccharides (Malx, where x = 4-8), which are composed of α-(1 → 4)-linked glucopyranose units. At the temperatures investigated (85-160 °C), the oligosaccharides dissociate at the glycosidic linkages or by the loss of a water molecule to produce B- or Y-type ions. The Y ions dissociate to smaller Y or B ions, while the B ions yield exclusively smaller B ions. The sequential loss of water molecules from the smallest B ions (B1 and B2) also occurs. Rate constants for dissociation of the protonated oligosaccharides and the corresponding Arrhenius activation parameters (Ea and A) were determined. The Ea and A-factors measured for protonated Malx (x > 4) are indistinguishable within error (~19 kcal mol-1, 1010 s-1), which is consistent with the ions being in the rapid energy exchange limit. In contrast, the Arrhenius parameters for protonated Cel6 (24 kcal mol-1, 1012 s-1) are significantly larger. These results indicate that both the energy and entropy changes associated with the glycosidic bond cleavage are sensitive to the anomeric configuration. Based on the results of this study, it is proposed that formation of B and Y ions occurs through a common dissociation mechanism, with the position of the proton establishing whether a B or Y ion is formed upon glycosidic bond cleavage.

  14. Cognitive behavioral hypnotherapy for dissociative disorders.

    PubMed

    Fine, Catherine G

    2012-04-01

    Dissociative disorders (DD) prevail as sequelae to overwhelming experiences in childhood. These readily formed post-traumatic responses and trance states develop in high hypnotizable subjects whose dysregulations become organized into ego states. A cognitive behavioral hypnotherapeutic treatment model will effectively contain, explore, metabolize, and resolve these life-endangering conditions. This article will detail the cognitive hypnotic world of DD patients, the relational spaces of the ego states, and the triphasic treatment mode to successfully resolve the dissociative pathology. Structured and phase appropriate hypnotic interventions will be described.

  15. Quantum Zeno control of coherent dissociation

    SciTech Connect

    Khripkov, C.; Vardi, A.

    2011-08-15

    We study the effect of dephasing on the coherent dissociation dynamics of an atom-molecule Bose-Einstein condensate. We show that when phase-noise intensity is strong with respect to the inverse correlation time of the stimulated process, dissociation is suppressed via a Bose enhanced quantum Zeno effect. This is complementary to the quantum Zeno control of phase-diffusion in a bimodal condensate by symmetric noise [Phys. Rev. Lett. 100, 220403 (2008)] in that the controlled process here is phase formation and the required decoherence mechanism for its suppression is purely phase noise.

  16. Phenol dissociation on pristine and defective graphene

    NASA Astrophysics Data System (ADS)

    Widjaja, Hantarto; Oluwoye, Ibukun; Altarawneh, Mohammednoor; Hamra, A. A. B.; Lim, H. N.; Huang, N. M.; Yin, Chun-Yang; Jiang, Zhong-Tao

    2017-03-01

    Phenol (C6H5O‒H) dissociation on both pristine and defective graphene sheets in terms of associated enthalpic requirements of the reaction channels was investigated. Here, we considered three common types of defective graphene, namely, Stone-Wales, monovacancy and divacancy configurations. Theoretical results demonstrate that, graphene with monovacancy creates C atoms with dangling bond (unpaired valence electron), which remains particularly useful for spontaneous dissociation of phenol into phenoxy (C6H5O) and hydrogen (H) atom. The reactions studied herein appear barrierless with reaction exothermicity as high as 2.2 eV. Our study offers fundamental insights into another potential application of defective graphene sheets.

  17. Upregulation of class I major histocompatibility complex gene expression in primary sensory neurons, satellite cells, and Schwann cells of mice in response to acute but not latent herpes simplex virus infection in vivo

    PubMed Central

    1994-01-01

    Major histocompatibility complex (MHC) deficiency is typical of almost all resident cells in normal neural tissue. However, CD8+ T cells, which recognize antigenic peptides in the context of class I MHC molecules, are known to mediate clearance of herpes simplex virus (HSV) from spinal ganglia of experimentally infected mice, leading to the hypothesis that class I expression in the peripheral nervous system must be upregulated in response to HSV infection. In addressing this hypothesis it is shown, in BALB/c (H-2d) mice, that normally deficient class I transcripts transiently accumulate in peripheral nerve Schwann cells, ganglionic satellite cells, and primary sensory neurons, indicating that in each of these cell types class I expression is regulated at the transcriptional level in vivo. Furthermore, for 3-4 wk after infection, H-2Kd/Dd antigens are expressed by satellite and Schwann cells but not neurons, suggesting additional posttranscriptional regulation of class I synthesis in neurons. Alternatively, the class I RNAs induced in neurons may not be derived from classical class I genes. Factors regulating H-2 class I expression emanate from within infected ganglia, probably from infected neurons themselves. However, induction of class I molecules was not maintained during latency, when viral gene expression in neurons is restricted to a single region within the virus repeats. These data have implications for the long-term survival of cells in HSV-infected neural tissue. PMID:8064236

  18. Charge Transfer Dissociation of Complex Oligosaccharides: Comparison with Collision-Induced Dissociation and Extreme Ultraviolet Dissociative Photoionization

    NASA Astrophysics Data System (ADS)

    Ropartz, David; Li, Pengfei; Fanuel, Mathieu; Giuliani, Alexandre; Rogniaux, Hélène; Jackson, Glen P.

    2016-10-01

    The structural characterization of oligosaccharides still challenges the field of analytical chemistry. Tandem mass spectrometry offers many advantages toward this aim, although the generic fragmentation method (low-energy collision-induced dissociation) shows clear limitations and is often insufficient to retrieve some essential structural information on these molecules. In this work, we present the first application of helium charge transfer dissociation (He-CTD) to characterize the structure of complex oligosaccharides. We compare this method with low-energy collision-induced dissociation and extreme-ultraviolet dissociative photoionization (XUV-DPI), which was shown previously to ensure the successful characterization of complex glycans. Similarly to what could be obtained by XUV-DPI, He-CTD provides a complete description of the investigated structures by producing many informative cross-ring fragments and no ambiguous fragmentation. Unlike XUV-DPI, which is performed at a synchrotron source, He-CTD has the undeniable advantage of being implementable in a conventional benchtop ion trap in a conventional laboratory setting.

  19. Interventions for dissociated vertical deviation

    PubMed Central

    Hatt, Sarah R; Wang, Xue; Holmes, Jonathan M

    2015-01-01

    Background The term “strabismus” describes misalignment of the eyes. One or both eyes may deviate inward, outward, upward, or downward. Dissociated vertical deviation (DVD) is a well-recognized type of upward drifting of one or both eyes, which can occur in children or adults. DVD often develops in the context of infantile- or childhood-onset horizontal strabismus, either esotropia (inward-turning) or exotropia (outward-turning). For some individuals, DVD remains controlled and can only be detected during clinical testing. For others, DVD becomes spontaneously “manifest” and the eye drifts up of its own accord. Spontaneously manifest DVD can be difficult to control and often causes psychosocial concerns. Traditionally, DVD has been thought to be asymptomatic, although some individuals have double vision. More recently it has been suggested that individuals with DVD may also suffer from eyestrain. Treatment for DVD may be sought either due to psychosocial concerns or because of these symptoms. The standard treatment for DVD is a surgical procedure; non-surgical treatments are offered less commonly. Although there are many studies evaluating different management options for the correction of DVD, a lack of clarity remains regarding which treatments are most effective. Objectives The objective of this review was to determine the effectiveness and safety of various surgical and non-surgical interventions in randomized controlled trials of participants with DVD. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2015, Issue 8), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to August 2015), EMBASE (January 1980 to August 2015), PubMed (1948 to August 2015), Latin American and Caribbean Health Sciences Literature Database (LILACS) (1982 to August 2015), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) (last searched 3

  20. Gα14 subunit-mediated inhibition of voltage-gated Ca2+ and K+ channels via neurokinin-1 receptors in rat celiac-superior mesenteric ganglion neurons.

    PubMed

    Sugino, Shigekazu; Farrag, Mohamed; Ruiz-Velasco, Victor

    2016-03-01

    The mechanisms by which G proteins modulate voltage-gated Ca(2+)channel currents (CaV), particularly CaV2.2 and CaV2.3, are voltage dependent (VD) or voltage independent (VI). VD pathways are typically mediated by Gαi/oand GαSsubfamilies. On the other hand, VI inhibition modulation is coupled to the Gαqsubfamily and signaling pathways downstream of phospholipase C stimulation. In most studies, this latter pathway has been shown to be linked to Gαqand/or Gα11protein subunits. However, there are no studies that have examined whether natively expressed Gα14subunits (Gαqsubfamily member) couple G protein-coupled receptors (GPCR) with CaV2.2 channels. We report that Gα14subunits functionally couple the substance P (SP)/neurokinin-1 (NK-1) receptor pathway to CaV2.2 channels in acutely dissociated rat celiac-superior mesenteric ganglion (CSMG) neurons. Exposure of CSMG neurons to SP blocked the CaV2.2 currents in a predominantly VD manner that was pertussis toxin and cholera toxin resistant, as well as Gαq/11independent. However, silencing Gα14subunits significantly attenuated the SP-mediated Ca(2+)current block. In another set of experiments, exposure of CSMG neurons to SP led to the inhibition of KCNQ K(+)M-currents. The SP-mediated M-current block was significantly reduced in neurons transfected with Gα14small-interference RNA. Finally, overexpression of the GTP-bound Gαq/11binding protein RGS2 did not alter the block of M-currents by SP but significantly abolished the oxotremorine methiodide-mediated M-current inhibition. Taken together, these results provide evidence of a new Gα14-coupled signaling pathway that modulates CaV2.2 and M-currents via SP-stimulated NK-1 receptors in CSMG neurons.

  1. On the excitatory effects of ATP and its role as a neurotransmitter in coeliac neurons of the guinea-pig.

    PubMed Central

    Silinsky, E M; Gerzanich, V

    1993-01-01

    1. The effects of ATP on neurons from guinea-pig coeliac ganglia were studied to evaluate the possibility that this nucleotide acts as an excitatory neurotransmitter substance. 2. In experiments with intracellular microelectrodes, ATP (> or = 10 nM) depolarized coeliac neurons from the resting potential and produced an increase in the membrane conductance. These excitatory effects of ATP were observed in isolated coeliac ganglia, in acutely dissociated neurons or in cultured neurons. ATP also produced membrane conductance increases in neurons clamped at the resting potential using a single electrode voltage clamp. 3. When studied in the whole-cell configuration of the patch clamp (intracellular Cs+ to block K+ currents; -50 mV holding potential), ATP evoked inward currents in a manner more potent and efficacious than acetylcholine (ACh). 4. Whole-cell currents induced by ATP were inwardly rectifying and reversed at -13 mV in normal Na+ solutions. Changes in extracellular Na+ concentration altered the reversal potential in a manner predicted by the Goldman-Hodgkin-Katz bi-ionic equation with a ratio of Na+ to Cs+ permeability (PNa/PCs) = 0.6. 5. Single channel currents were evoked by ATP in excised (outside-out) patches. Current-voltage relationships for single channel currents exhibited inward rectification. The mean single channel conductance was 22 pS at -50 mV. 6. Antagonists of ATP-gated channels (suramin, Reactive Blue 2) reduced the effects of ATP but not ACh. 7. Antagonists at nicotinic receptors/ion channels (hexamethonium or tubocurarine) reduced the effects of ACh but not ATP. 8. Excitatory synaptic currents were observed in cultures of coeliac neurons. Synaptic currents possessed similar current-voltage relationships to currents produced by ATP, were increased in frequency by K+ depolarization in a Ca(2+)-dependent manner, and were selectively antagonized by ATP antagonists. 9. Local K+ depolarization of the ends of neurites evoked single channel

  2. Interaction and intelligence in living neuronal networks interfaced with moving robot

    NASA Astrophysics Data System (ADS)

    Kudoh, Suguru N.; Taguchi, Takahisa

    2006-01-01

    Neurons form complex networks and it seems that the living neuronal network can perform certain type of information processing. We are interested in intelligence autonomously formed in vitro. The most important features of the two-dimensional culture neural network are that it is a system in which the information processing is autonomously carries out. We reported previously that the functional connections were dynamically modified by synaptic potentiation and the process may be required for reorganization of the functional group of neurons. Such neuron assemblies are critical for information processing in brain. Certain types of feedback stimulation caused suppression of spontaneous network electrical activities and drastic re-organization of functional connections between neurons, when these activities are initially almost synchronized. The result suggests that neurons in dissociated culture autonomously re-organized their functional neuronal networks interacted with their environment. The spatio-temporal pattern of activity in the networks may be a reflection of their external environment. We also interfaced the cultured neuronal network with moving robot. The planar microelectrodes can be used for detecting neuronal electrical signals from the living neuronal network cultured on a 2-dimensional electrode array. The speed of actuators of moving robot was determined by these detected signals. Our goal is reconstruction of the neural network, which can process "thinking" in the dissociated culture system.

  3. Matrix Metalloproteinase-9 Regulates Neuronal Circuit Development and Excitability.

    PubMed

    Murase, Sachiko; Lantz, Crystal L; Kim, Eunyoung; Gupta, Nitin; Higgins, Richard; Stopfer, Mark; Hoffman, Dax A; Quinlan, Elizabeth M

    2016-07-01

    In early postnatal development, naturally occurring cell death, dendritic outgrowth, and synaptogenesis sculpt neuronal ensembles into functional neuronal circuits. Here, we demonstrate that deletion of the extracellular proteinase matrix metalloproteinase-9 (MMP-9) affects each of these processes, resulting in maladapted neuronal circuitry. MMP-9 deletion increases the number of CA1 pyramidal neurons but decreases dendritic length and complexity. Parallel changes in neuronal morphology are observed in primary visual cortex and persist into adulthood. Individual CA1 neurons in MMP-9(-/-) mice have enhanced input resistance and a significant increase in the frequency, but not amplitude, of miniature excitatory postsynaptic currents (mEPSCs). Additionally, deletion of MMP-9 significantly increases spontaneous neuronal activity in awake MMP-9(-/-) mice and enhances response to acute challenge by the excitotoxin kainate. Our data document a novel role for MMP-9-dependent proteolysis: the regulation of several aspects of circuit maturation to constrain excitability throughout life.

  4. Peritraumatic Distress and Dissociation in Prolonged Grief and Posttraumatic Stress Following Violent and Unexpected Deaths.

    PubMed

    Boelen, Paul A

    2015-01-01

    This study examined associations between the violence of a loss and the suddenness of a loss and symptom levels of prolonged grief disorder (PGD) and posttraumatic stress disorder (PTSD) after the death of a loved one. A further aim was to investigate whether peritraumatic distress (i.e., fear, helplessness, and horror) and peritraumatic dissociation mediate the emotional impact of violent losses and unexpected losses. We obtained self-reported data from 265 individuals bereaved in the previous 3 years by losses due to violent causes (17%) or illness (83%). Outcomes showed that participants who experienced violent losses (due to homicide, suicide, or accident) reported more PGD symptoms and PTSD symptoms compared to those confronted with illness loss. In this latter group, greater perceived unexpectedness was positively associated with PGD severity and PTSD severity. Multiple mediation analyses showed that the impact of violent loss and unexpectedness of the loss on PGD severity and PTSD severity was fully mediated by peritraumatic distress and dissociation; peritraumatic helplessness and peritraumatic dissociation (but not peritraumatic fear and horror) emerged as unique mediators. Findings suggest that both violent and unexpected losses exacerbate postloss psychopathology, which is at least partially because of such losses yielding more intense acute helplessness and dissociative responses.

  5. Cortical neurons exposed to glutamate rapidly leak preloaded chromium 51

    SciTech Connect

    Maulucci-Gedde, M.; Choi, D.W.

    1987-05-01

    The acute toxic effects of excess glutamate exposure on cortical neurons in culture was followed using a novel adaptation of the /sup 51/Cr efflux assay. Although the acute, sodium-dependent phase of glutamate neurotoxicity may contribute to several acute disease settings, including sustained seizures and stroke, functional aspects of the phenomenon have not been previously studied. We report here that the earliest morphologic sign of glutamate neurotoxicity, neuronal swelling, is accompanied by a large efflux of complexed /sup 51/Cr from preloaded neurons in the first hour after exposure, and that this efflux is detectable as early as 15 min after the onset of glutamate exposure. We suggest that this pathological burst of /sup 51/Cr may result from glutamate-induced leakiness of neuronal cell membranes.

  6. Hypnotizability and Dissociativity in Sexually Abused Girls.

    ERIC Educational Resources Information Center

    Putnam, Frank W.; And Others

    1995-01-01

    This study assessed the relationships among hypnotizability, clinical dissociation and traumatic antecedents in 54 sexually abused girls, ages 6 to 15 years, and 51 matched controls. There were no significant differences in hypnotizability between abuse and control subjects. However, in the abuse group, highly hypnotizable subjects were…

  7. The Infrared Multiphoton Dissociation of Three Nitrolkanes.

    DTIC Science & Technology

    1986-01-24

    eam experiment, using infrared multiphoton dissociation where the concept of temperature has no place, can be quantitatively related to pyrolysis ...respectively. This large release of translational energy is suggested to be due to the nature of the transition state mechanical barrier which is largely...to pyrolysis experiments which are conducted under collisional, thermal conditions and measure phenomenological quantities such as activation energies

  8. Dissociative Reactions to the Bay Area Earthquake.

    ERIC Educational Resources Information Center

    Cardena, Etzel; Spiegel, David

    This study systematically evaluated the psychological reactions of a non-clinical population to the October 1989 Bay Area earthquake. Within a week of the earthquake, a checklist of anxiety and dissociative symptoms was administered to a representative sample of approximately 100 graduate students and faculty members from two different…

  9. Process Dissociation and Mixture Signal Detection Theory

    ERIC Educational Resources Information Center

    DeCarlo, Lawrence T.

    2008-01-01

    The process dissociation procedure was developed in an attempt to separate different processes involved in memory tasks. The procedure naturally lends itself to a formulation within a class of mixture signal detection models. The dual process model is shown to be a special case. The mixture signal detection model is applied to data from a widely…

  10. Dissociative recombination: Results from storage rings

    SciTech Connect

    Larsson, Mats

    2005-05-27

    The focus of this article is on the measurement of product branching ratios in the dissociative recombination of polyatomic molecular ions with electrons by means of ion storage rings. Recombination of ions of interest in astrophysics, plasma-assisted combustion, thermonuclear fusion, protein fragmentation, and atmospheric physics are reviewed and discussed.

  11. Subliminal processes, dissociation and the 'I'.

    PubMed

    Bob, Petr

    2003-06-01

    The study of unconscious processes leads to the hypothesis of the limit of consciousness, which involves two main kinds of psychic activity. The first represents psychic contents which are subliminal for their low energy, the second subliminal contents which are inaccessible to consciousness because they are dissociated in the subliminal region. Dissociation is a concept introduced by Pierre Janet for splitting consciousness due to traumatic events or during hypnosis. It takes a more general form in Hilgard's neo-dissociation theory of hypnotic phenomena and also in Jung's theory of the collective unconscious. Further generalization links it to the modern findings of explicit and implicit perception, leading to a shift in dissociation from hypothesis to clinical, experimental and theoretical reality. Studies in hypnosis also point to the existence of an integrative psychic entity, that comprises the conscious 'I'. Hilgard called this the hidden observer, and his findings represent empirical confirmation of Jung's term for the Self as mirror 'I', which leads to many important consequences for self-discovery and the meaning of life.

  12. Psychotherapy and Pharmacotherapy for Patients with Dissociative Identity Disorder

    PubMed Central

    Gentile, Julie P.; Dillon, Kristy S.

    2013-01-01

    There is a wide variety of what have been called “dissociative disorders,” including dissociative amnesia, dissociative fugue, depersonalization disorder, dissociative identity disorder, and forms of dissociative disorder not otherwise specified. Some of these diagnoses, particularly dissociative identity disorder, are controversial and have been questioned by many clinicians over the years. The disorders may be under-diagnosed or misdiagnosed, but many persons who have experienced trauma report “dissociative” symptoms. Prevalence of dissociative disorders is unknown, but current estimates are higher than previously thought. This paper reviews clinical, phenomenological, and epidemiological data regarding diagnosis in general, and illustrates possible treatment interventions for dissociative identity disorder, with a focus on psychotherapy interventions and a review of current psychopharmacology recommendations as part of a comprehensive multidisciplinary treatment plan. PMID:23556139

  13. Thermal dissociation behavior and dissociation enthalpies of methane-carbon dioxide mixed hydrates

    SciTech Connect

    Kwon, T.H.; Kneafsey, T.J.; Rees, E.V.L.

    2011-02-15

    Replacement of methane with carbon dioxide in hydrate has been proposed as a strategy for geologic sequestration of carbon dioxide (CO{sub 2}) and/or production of methane (CH{sub 4}) from natural hydrate deposits. This replacement strategy requires a better understanding of the thermodynamic characteristics of binary mixtures of CH{sub 4} and CO{sub 2} hydrate (CH{sub 4}-CO{sub 2} mixed hydrates), as well as thermophysical property changes during gas exchange. This study explores the thermal dissociation behavior and dissociation enthalpies of CH{sub 4}-CO{sub 2} mixed hydrates. We prepared CH{sub 4}-CO{sub 2} mixed hydrate samples from two different, well-defined gas mixtures. During thermal dissociation of a CH{sub 4}-CO{sub 2} mixed hydrate sample, gas samples from the head space were periodically collected and analyzed using gas chromatography. The changes in CH{sub 4}-CO{sub 2} compositions in both the vapor phase and hydrate phase during dissociation were estimated based on the gas chromatography measurements. It was found that the CO{sub 2} concentration in the vapor phase became richer during dissociation because the initial hydrate composition contained relatively more CO{sub 2} than the vapor phase. The composition change in the vapor phase during hydrate dissociation affected the dissociation pressure and temperature; the richer CO{sub 2} in the vapor phase led to a lower dissociation pressure. Furthermore, the increase in CO{sub 2} concentration in the vapor phase enriched the hydrate in CO{sub 2}. The dissociation enthalpy of the CH{sub 4}-CO{sub 2} mixed hydrate was computed by fitting the Clausius-Clapeyron equation to the pressure-temperature (PT) trace of a dissociation test. It was observed that the dissociation enthalpy of the CH{sub 4}-CO{sub 2} mixed hydrate lays between the limiting values of pure CH{sub 4} hydrate and CO{sub 2} hydrate, increasing with the CO{sub 2} fraction in the hydrate phase.

  14. Childhood Traumatic Experiences, Dissociative Symptoms, and Dissociative Disorder Comorbidity Among Patients With Panic Disorder: A Preliminary Study.

    PubMed

    Ural, Cenk; Belli, Hasan; Akbudak, Mahir; Tabo, Abdulkadir

    2015-01-01

    This study assessed childhood trauma history, dissociative symptoms, and dissociative disorder comorbidity in patients with panic disorder (PD). A total of 92 psychotropic drug-naive patients with PD, recruited from outpatient clinics in the psychiatry department of a Turkish hospital, were involved in the study. Participants were assessed using the Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D), Dissociation Questionnaire, Panic and Agoraphobia Scale, Panic Disorder Severity Scale, and Childhood Trauma Questionnaire. Of the patients with PD, 18 (19%) had a comorbid dissociative disorder diagnosis on screening with the SCID-D. The most prevalent disorders were dissociative disorder not otherwise specified, dissociative amnesia, and depersonalization disorders. Patients with a high degree of dissociation symptoms and dissociative disorder comorbidity had more severe PD than those without (p < .05). All of the childhood trauma subscales used were correlated with the severity of symptoms of dissociation and PD. Among all of the subscales, the strongest relationship was with childhood emotional abuse. Logistic regression analysis showed that emotional abuse and severity of PD were independently associated with dissociative disorder. In our study, a significant proportion of the patients with PD had concurrent diagnoses of dissociative disorder. We conclude that the predominance of PD symptoms at admission should not lead the clinician to overlook the underlying dissociative process and associated traumatic experiences among these patients.

  15. What contributes to predicting change in the treatment of dissociation: initial levels of dissociation, PTSD, or overall distress?

    PubMed

    Brand, Bethany L; Stadnik, Ryan

    2013-01-01

    Individuals with dissociative disorders (DDs) suffer from high levels of dissociation as well as posttraumatic stress disorder (PTSD) and general distress. No research has investigated how changes in dissociation relate to changes in other symptoms over the course of treatment in patients with DD. Using a prospective, naturalistic design, we collected reports of symptoms from a sample of therapists and their patients diagnosed with dissociative identity disorder or dissociative disorder not otherwise specified who participated in the Treatment Outcome of Patients with Dissociative Disorders study. The patients completed surveys at intake (Time 1) into the study and at 30-month follow-up (Time 4). We found that dissociative symptoms, including amnesia, depersonalization/derealization, and absorption, at the initial assessment of the study ("initial") were related to initial levels of PTSD and general distress and that changes in dissociative symptoms were related to changes in PTSD and general distress. Initial dissociation was a significant predictor of change in dissociation at 30 months when we controlled for length of time for follow-up, length of time practicing therapy, and length of time treating dissociative patients. Our results suggest that a reduction in dissociative symptoms in DD patients is associated with reductions in the overall severity of dissociative, posttraumatic stress, and distress symptoms.

  16. Chronic CXCL10 Alters Neuronal Properties in Rat Hippocampal Culture

    PubMed Central

    Cho, Jungsook; Nelson, Thomas E.; Bajova, Hilda; Gruol, Donna L.

    2009-01-01

    The chemokine CXCL10 is expressed in the central nervous system (CNS) during neuroinflammatory conditions. Neurons express CXCR3, the receptor for CXCL10, and neuronal function has been shown to be altered by acute exposure to CXCL10. Little is known about the effects of chronic exposure to CXCL10 on neuronal function. Results from our studies show that chronic exposure of cultured rat hippocampal neurons to CXCL10 results in altered levels of protein for GABA and glutamate receptors and altered synaptic network activity. These effects of CXCL10 may contribute to altered CNS function that occurs in some chronic neuroinflammatory conditions. PMID:19167097

  17. Dissociative electron attachment to water molecule: Experimental study of the dissociation dynamics

    NASA Astrophysics Data System (ADS)

    Adaniya, H.; Rudek, B.; Osipov, T.; Weber, T.; Lee, S.; Hertlein, M.; Schoeffler, M.; Prior, M.; Belkacem, A.

    2009-11-01

    The dynamics of the dissociative electron attachment(DEA)to water(H2O, D2O)via three resonances, 2B1, 2A1, 2B2, are investigated using the modified Coltrims spectrometer. The angular dependence of the negative ion shows unique distribution in each resonance indicating the three resonances involve different dissociation dynamics. The energy distribution among the fragments shows considerable amount of three body break.

  18. Vertical nanowire electrode array: a highly scalable platform for intracellular interfacing to neuronal circuits

    NASA Astrophysics Data System (ADS)

    Jorgolli, Marsela; Robinson, Jacob; Shalek, Alex; Yoon, Myung-Han; Gertner, Rona; Park, Hongkun

    2012-02-01

    Interrogation of complex neuronal network requires new experimental tools that are sensitive enough to quantify the strengths of synaptic connections, yet scalable enough to couple to a large number of neurons simultaneously. Here, we will present a new, highly scalable intracellular electrode platform based on vertical nanowires that affords parallel interfacing to multiple mammalian neurons. Specifically, we show that our vertical nanowire electrode arrays can intracellularly record and stimulate neuronal activity in dissociated cultures of rat cortical neurons and be used to map multiple individual synaptic connections. This platform's scalability and full compatibility with silicon nanofabrication techniques provide a clear path toward simultaneous high-fidelity interfacing with hundreds of individual neurons, opening up exciting new avenues for neuronal circuit studies and prosthetics.

  19. Network dynamics of cultured hippocampal neurons in a multi-electrode array

    NASA Astrophysics Data System (ADS)

    Taguchi, Takahisa; Kudoh, Suguru N.

    2005-02-01

    The neurons in dissociation culture autonomously re-organized their functional neuronal networks, after the process for elongating neurites and establishing synaptic connections. The spatio-temporal patterns of activity in the networks might be a reflection of functional neuron assemblies. The functional connections were dynamically modified by synaptic potentiation and the process may be required for reorganization of the functional group of neurons. Such neuron assemblies are critical for information processing in brain. To visualize the functional connections between neurons, we have analyzed the autonomous activity of synaptically induced action potentials in the living neuronal networks on a multi-electrode array, using "connection map analysis" that we developed for this purpose. Moreover, we designed aan original wide area covering electrode array and succeeded in recording spontaneous action potentials from wider area than commercial multi electrode arrays.

  20. Dopamine antagonists reduce spontaneous electrical activity in cultured mammalian neurons from ventral mesencephalon.

    PubMed

    Heyer, E J

    1986-09-24

    Mammalian neurons from ventral mesencephalon (VM) were grown in primary dissociated cell (PDC) culture. These neurons are predominantly non-dopaminergic. Many of these non-dopaminergic neurons have dopamine agonist and antagonist binding sites. Intracellular recordings were obtained from these neurons. When bathed in phosphate-buffered saline (PBS) solution they generated action potentials spontaneously. However, in the presence of haloperidol dissolved in PBS solution, the percentage of neurons which generated action potentials spontaneously was reduced in a dose-dependent manner (1-10 microM). This response was also obtained with (+) butaclamol (1 microM) but not with (-) butaclamol (1 microM). This neuroleptic inhibition of spontaneously generated action potentials was specific for neurons in PDC cultures of VM since neurons in PDC cultures of spinal cord did not demonstrate this phenomenon.

  1. Dissociation techniques in mass spectrometry-based proteomics.

    PubMed

    Jones, Andrew W; Cooper, Helen J

    2011-09-07

    The field of proteomics, the large-scale analysis of proteins, has undergone a huge expansion over the past decade. Mass spectrometry-based proteomics relies on the dissociation of peptide and/or protein ions to provide information on primary sequence and sites of post-translational modifications. Fragmentation techniques include collision-induced dissociation, electron capture dissociation and electron transfer dissociation. Here, we describe each of these techniques and their use in proteomics. The principles, advantages, limitations, and applications are discussed.

  2. Dissociation and dissociative ionization of H2+ using the time-dependent surface flux method

    NASA Astrophysics Data System (ADS)

    Yue, Lun; Madsen, Lars Bojer

    2013-12-01

    The time-dependent surface flux method developed for the description of electronic spectra L. Tao and A. Scrinzi, New J. Phys. 14, 013021 (2012), 10.1088/1367-2630/14/1/013021; A. Scrinzi, New J. Phys. 14, 085008 (2012), 10.1088/1367-2630/14/8/085008] is extended to treat dissociation and dissociative ionization processes of H2+ interacting with strong laser pulses. By dividing the simulation volume into proper spatial regions associated with the individual reaction channels and monitoring the probability flux, the joint energy spectrum for the dissociative ionization process and the energy spectrum for dissociation is obtained. The methodology is illustrated by solving the time-dependent Schrödinger equation for a collinear one-dimensional model of H2+ with electronic and nuclear motions treated exactly and validated by comparison with published results for dissociative ionization. The results for dissociation are qualitatively explained by analysis based on dressed diabatic Floquet potential energy curves, and the method is used to investigate the breakdown of the two-surface model.

  3. Does phasic trauma treatment make patients with dissociative identity disorder treatment more dissociative?

    PubMed

    Brand, Bethany; Loewenstein, Richard J

    2014-01-01

    Proponents of the iatrogenic model of the etiology of dissociative identity disorder (DID) have expressed concern that treatment focused on direct engagement and interaction with dissociated self-states harms DID patients. However, empirical data have shown that this type of DID treatment is beneficial. Analyzing data from the prospective Treatment of Patients With Dissociative Disorders (TOP DD) Study, we test empirically whether DID treatment is associated with clinically adverse manifestations of dissociated self-states: acting so differently that one feels like different people, hearing voices, and dissociative amnesia. We show that, over the course of the study, there were significant decreases in feeling like different people and hearing voices. These results indicate that this form of DID treatment does not lead to symptomatic worsening in these dimensions, as predicted by the iatrogenic model. Indeed, treatment provided by TOP DD therapists reduced, rather than increased, the extent to which patients experienced manifestations of pathological dissociation. Because severe symptomatology and impairment are associated with DID, iatrogenic harm may come from depriving DID patients of treatment that targets DID symptomatology.

  4. Assessment of complex dissociative disorder patients and simulated dissociation in forensic contexts.

    PubMed

    Brand, Bethany L; Webermann, Aliya R; Frankel, A Steven

    Few assessors receive training in assessing dissociation and complex dissociative disorders (DDs). Potential differential diagnoses include anxiety, mood, psychotic, substance use, and personality disorders, as well as exaggeration and malingering. Individuals with DDs typically elevate on many clinical and validity scales on psychological tests, yet research indicates that they can be distinguished from DD simulators. Becoming informed about the testing profiles of DD individuals and DD simulators can improve the accuracy of differential diagnoses in forensic settings. In this paper, we first review the testing profiles of individuals with complex DDs and contrast them with DD simulators on assessment measures used in forensic contexts, including the Minnesota Multiphasic Personality Inventory-2 (MMPI-2), Personality Assessment Inventory (PAI), and the Structured Inventory of Reported Symptoms (SIRS), as well as dissociation-specific measures such as the Dissociative Experiences Scale (DES) and Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D-R). We then provide recommendations for assessing complex trauma and dissociation through the aforementioned assessments.

  5. Predictors of trait dissociation and peritraumatic dissociation induced via cold pressor.

    PubMed

    Gómez-Pérez, Lydia; López-Martínez, Alicia Eva; Asmundson, Gordon John Glenn

    2013-11-30

    Understanding which factors predict individual dissociative response during stressful situations is important to clarify the nature of dissociation and the mechanisms associated to its use as a coping strategy. The present study examined (1) whether experiential avoidance (EA), anxiety sensitivity (AS), depressive symptoms, and state anxiety concurrently predicted trait dissociation (TD)-absorption, amnesia, depersonalization, and total TD scores-and laboratory induced dissociation (LID); and (2) whether TD and catastrophizing predicted LID. We also examined whether catastrophizing mediated the relationships between both AS and depressive symptoms and LID. A total of 101 female undergraduate students participated in a cold pressor task, which significantly induced dissociation. Results of hierarchical regression analyses showed that AS at Time 1 (9 months before the experimental session), as well as depressive symptoms and catastrophizing at the time of the experiment (Time 2), predicted LID at Time 2. Depressive symptoms at Time 2 predicted total TD, absorption, and amnesia scores. AS at Time 1 and depressive symptoms at Time 2 predicted depersonalization. AS, depressive symptoms, and catastrophizing seem to facilitate the use of dissociative strategies by healthy individuals, even in response to non-traumatic but discomforting stress.

  6. Neuronal representation of object orientation.

    PubMed

    Karnath, H O; Ferber, S; Bülthoff, H H

    2000-01-01

    The dissociation between object identity and object orientation observed in six patients with brain damage, has been taken as evidence for a view-invariant model of object recognition. However, there was also some indication that these patients were not generally agnosic for object orientation but were able to gain access to at least some information about objects' canonical upright. We studied a new case (KB) with spared knowledge of object identity and impaired perception of object orientation using a forced choice paradigm to contrast directly the patient's ability to perceive objects' canonical upright vs non-upright orientations. We presented 2D-pictures of objects with unambiguous canonical upright orientations in four different orientations (0 degrees, -90 degrees, +90 degrees, 180 degrees ). KB showed no impairment in identifying letters, objects, animals, or faces irrespective of their given orientation. Also, her knowledge of upright orientation of stimuli was perfectly preserved. In sharp contrast, KB was not able to judge the orientation when the stimuli were presented in a non-upright orientation. The findings give further support for a distributed view-based representation of objects in which neurons become tuned to the features present in certain views of an object. Since we see more upright than inverted animals and familiar objects, the statistics of these images leads to a larger number of neurons tuned for objects in an upright orientation. We suppose that probably for this reason KB's knowledge of upright orientation was found to be more robust against neuronal damage than knowledge of other orientations.

  7. Forgetting heart break: a fascinating case of transient left ventricular apical ballooning syndrome associated with dissociative amnesia.

    PubMed

    Toussi, Amir; Bryk, Jodie; Alam, Abdulkader

    2014-01-01

    Transient left ventricular apical ballooning syndrome (TLVABS), also known as takotsubo cardiomyopathy, is characterized by transient left ventricular dysfunction, electrocardiographic changes, and release of myocardial enzymes that mimic acute myocardial infarction in patients without angiographic evidence of coronary artery disease. Most patients are post-menopausal women and an emotional or physiologic stressor frequently precedes the presentation. Psychogenic or dissociative amnesia is a memory disorder characterized by sudden retrograde memory loss with inability to recall personal information said to occur for a period of time ranging from hours to years after a stressful event. Interestingly, the mechanism of both disorders has been linked to plasma elevation in catecholamines. Here we present the case of a 66-year-old female diagnosed with both TLVABS and dissociative amnesia following the sudden unexpected death of her sister. To our knowledge, this is surprisingly the first report of the co-occurrence of TLVABS and dissociative amnesia, two processes with a potential shared underlying etiology.

  8. Sexually dimorphic neuronal responses to social isolation

    PubMed Central

    Senst, Laura; Baimoukhametova, Dinara; Sterley, Toni-Lee; Bains, Jaideep Singh

    2016-01-01

    Many species use social networks to buffer the effects of stress. The mere absence of a social network, however, may also be stressful. We examined neuroendocrine, PVN CRH neurons and report that social isolation alters the intrinsic properties of these cells in sexually dimorphic fashion. Specifically, isolating preadolescent female mice from littermates for <24 hr increased first spike latency (FSL) and decreased excitability of CRH neurons. These changes were not evident in age-matched males. By contrast, subjecting either males (isolated or grouped) or group housed females to acute physical stress (swim), increased FSL. The increase in FSL following either social isolation or acute physical stress was blocked by the glucocorticoid synthesis inhibitor, metyrapone and mimicked by exogenous corticosterone. The increase in FSL results in a decrease in the excitability of CRH neurons. Our observations demonstrate that social isolation, but not acute physical stress has sex-specific effects on PVN CRH neurons. DOI: http://dx.doi.org/10.7554/eLife.18726.001 PMID:27725087

  9. 21 CFR 886.1910 - Spectacle dissociation test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Spectacle dissociation test system. 886.1910... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1910 Spectacle dissociation test system. (a) Identification. A spectacle dissociation test system is an AC-powered or...

  10. Cognitive Processes in Dissociation: Comment on Giesbrecht et al. (2008)

    ERIC Educational Resources Information Center

    Bremner, J. Douglas

    2010-01-01

    In their recent review "Cognitive Processes in Dissociation: An Analysis of Core Theoretical Assumptions," published in "Psychological Bulletin", Giesbrecht, Lynn, Lilienfeld, and Merckelbach (2008) have challenged the widely accepted trauma theory of dissociation, which holds that dissociative symptoms are caused by traumatic stress. In doing so,…

  11. 21 CFR 886.1910 - Spectacle dissociation test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Spectacle dissociation test system. 886.1910... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1910 Spectacle dissociation test system. (a) Identification. A spectacle dissociation test system is an AC-powered or...

  12. 21 CFR 886.1910 - Spectacle dissociation test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Spectacle dissociation test system. 886.1910... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1910 Spectacle dissociation test system. (a) Identification. A spectacle dissociation test system is an AC-powered or...

  13. 21 CFR 886.1910 - Spectacle dissociation test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Spectacle dissociation test system. 886.1910... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1910 Spectacle dissociation test system. (a) Identification. A spectacle dissociation test system is an AC-powered or...

  14. Cognitive Processes in Dissociation: An Analysis of Core Theoretical Assumptions

    ERIC Educational Resources Information Center

    Giesbrecht, Timo; Lilienfield, Scott O.; Lynn, Steven Jay; Merckelbach, Harald

    2008-01-01

    Dissociation is typically defined as the lack of normal integration of thoughts, feelings, and experiences into consciousness and memory. The present article critically evaluates the research literature on cognitive processes in dissociation. The authors' review indicates that dissociation is characterized by subtle deficits in neuropsychological…

  15. 21 CFR 886.1910 - Spectacle dissociation test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Spectacle dissociation test system. 886.1910... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1910 Spectacle dissociation test system. (a) Identification. A spectacle dissociation test system is an AC-powered or...

  16. The Parenting Experiences of Mothers with Dissociative Disorders.

    ERIC Educational Resources Information Center

    Benjamin, Lynn R.; Benjamin, Robert; Rind, Bruce

    1998-01-01

    Presents a qualitative analysis of the experience of parenting of mothers with dissociative disorders. Using the mothers' words, describes how the five symptom areas of dissociation impeded their parenting efforts. Discusses the necessity of addressing parenting in the treatment of client-mothers with dissociative disorders. (Author/MKA)

  17. The Contribution of Art Therapy to the Dissociative Disorders.

    ERIC Educational Resources Information Center

    Murphy, Patricia S.

    1994-01-01

    Explored concepts of brain hemispheric lateralization and distinct right brain functioning in extensive dissociation by administering Dissociative Experiences Scale to 114 engineering students and 92 university drawing students. Chi-square calculation found differences in dissociative scoring levels between groups that approached significance at…

  18. Development, Reliability, and Validity of a Child Dissociation Scale.

    ERIC Educational Resources Information Center

    Putnam, Frank W.; And Others

    1993-01-01

    Evaluation of the Child Dissociative Checklist found it to be a reliable and valid observer report measure of dissociation in children, including sexually abused girls and children with dissociative disorder and with multiple personality disorder. The checklist, which is appended, is intended as a clinical screening instrument and research measure…

  19. The Relationships Between Dissociation, Attention, and Memory Dysfunction

    PubMed Central

    ÖZDEMİR, Osman; GÜZEL ÖZDEMİR, Pınar; BOYSAN, Murat; YILMAZ, Ekrem

    2015-01-01

    Introduction Dissociation is a disruption in the integrated functions of consciousness, memory, identity, and perception. Dissociative symptoms include derealization/depersonalization, absorption, and amnesia. These experiences can cause a loss of control over mental processes, including memory and attention. In literature, there is a paucity of research concerning the relationships between dissociation and memory performance. In this study, our aim was to investigate the relationships between dissociative experiences, attention, and memory performance in a non-clinical community sample. Methods In this study, we examined the relationship between dissociation and cognitive dysfunction among 60 healthy volunteers. We administered the Wechsler Memory Scale-Revised, Auditory Verbal Learning Test, Stroop Color Word Interference Test, and Dissociative Experience Scale. Here we examined the relationships between the subtypes of dissociation and memory performance as assessed by neuropsychological tests. Results We found that verbal memory was negatively associated with dissociative experiences. Pathological dissociation, particularly amnesia and depersonalization/derealization, was reversely linked to general memory performance and long-term memory. Moreover, low dissociators reported higher scores on verbal memory, general memory performance, and long-term memory but lower scores on recognition than high dissociators. Conclusion The results of our study suggested that there are significant linkages between dissociative experiences and memory performance.

  20. Speech-Language Dissociations, Distractibility, and Childhood Stuttering

    PubMed Central

    Conture, Edward G.; Walden, Tedra A.; Lambert, Warren E.

    2015-01-01

    Purpose This study investigated the relation among speech-language dissociations, attentional distractibility, and childhood stuttering. Method Participants were 82 preschool-age children who stutter (CWS) and 120 who do not stutter (CWNS). Correlation-based statistics (Bates, Appelbaum, Salcedo, Saygin, & Pizzamiglio, 2003) identified dissociations across 5 norm-based speech-language subtests. The Behavioral Style Questionnaire Distractibility subscale measured attentional distractibility. Analyses addressed (a) between-groups differences in the number of children exhibiting speech-language dissociations; (b) between-groups distractibility differences; (c) the relation between distractibility and speech-language dissociations; and (d) whether interactions between distractibility and dissociations predicted the frequency of total, stuttered, and nonstuttered disfluencies. Results More preschool-age CWS exhibited speech-language dissociations compared with CWNS, and more boys exhibited dissociations compared with girls. In addition, male CWS were less distractible than female CWS and female CWNS. For CWS, but not CWNS, less distractibility (i.e., greater attention) was associated with more speech-language dissociations. Last, interactions between distractibility and dissociations did not predict speech disfluencies in CWS or CWNS. Conclusions The present findings suggest that for preschool-age CWS, attentional processes are associated with speech-language dissociations. Future investigations are warranted to better understand the directionality of effect of this association (e.g., inefficient attentional processes → speech-language dissociations vs. inefficient attentional processes ← speech-language dissociations). PMID:26126203

  1. Rate coefficients for dissociative attachment and resonant electron-impact dissociation involving vibrationally excited O{sub 2} molecules

    SciTech Connect

    Laporta, V.; Celiberto, R.; Tennyson, J.

    2014-12-09

    Rate coefficients for dissociative electron attachment and electron-impact dissociation processes, involving vibrationally excited molecular oxygen, are presented. Analytical fits of the calculated numerical data, useful in the applications, are also provided.

  2. Characterization of membrane currents in dissociated adult rat pineal cells.

    PubMed Central

    Aguayo, L G; Weight, F F

    1988-01-01

    1. Membrane currents, particularly the outward components, were studied in pineal cells acutely dissociated from adult rats using the whole-cell variant of the patch-clamp technique. 2. In current clamp, outward constant current elicited a transient graded depolarizing response. A sustained membrane rectification developed within 20 ms; this phenomenon was reduced in cells internally dialysed with 120 mM-CsCl. 3. Study of the membrane current revealed the existence of a transient and a delayed outward current. These currents were virtually eliminated when the cell was internally dialysed with CsCl. 4. The delayed outward current, isolated from a holding potential of -50 mV, activated at potentials near -20 mV, reached a steady-state current amplitude within 60 ms and had little or no decay during steps up to 400 ms in duration. This component was reduced by 80% or more with the addition of 5 mM-TEA. 5. From -100 mV, the transient outward current reached a peak within 15 ms and decayed with a single-exponential time course. The mean decay time constant was 66 +/- 10 ms (at -33 mV) and it showed little voltage sensitivity. This current, which activated at potentials positive to -60 mV and displayed half-inactivation at -76 +/- 8 mV, was reduced by 50% with the addition of 5 mM-4-AP (4-amino-pyridine). 6. In the presence of external Ca2+, the current-voltage relationship for the delayed current did not display a region of negative-slope conductance (N-shape). Increasing the intracellular ionized Ca2+ concentration by varying the Ca-EGTA buffer ratio did not alter the dependence of the current on the membrane potential. 7. Block of outward currents with internal Cs+ revealed a small (less than 90 pA) inward Ca2+ current when the external Ca2+ concentration was increased to 10 mM. From a holding potential of -50 mV, it had a threshold at -30 mV and peaked at +5 mV. Evidence for an inward Na+ current was not obtained. 8. We conclude that acutely dissociated pineal cells

  3. Signal Propagation between Neuronal Populations Controlled by Micropatterning

    PubMed Central

    Albers, Jonas; Offenhäusser, Andreas

    2016-01-01

    The central nervous system consists of an unfathomable number of functional networks enabling highly sophisticated information processing. Guided neuronal growth with a well-defined connectivity and accompanying polarity is essential for the formation of these networks. To investigate how two-dimensional protein patterns influence neuronal outgrowth with respect to connectivity and functional polarity between adjacent populations of neurons, a microstructured model system was established. Exclusive cell growth on patterned substrates was achieved by transferring a mixture of poly-l-lysine and laminin to a cell-repellent glass surface by microcontact printing. Triangular structures with different opening angle, height, and width were chosen as a pattern to achieve network formation with defined behavior at the junction of adjacent structures. These patterns were populated with dissociated primary cortical embryonic rat neurons and investigated with respect to their impact on neuronal outgrowth by immunofluorescence analysis, as well as their functional connectivity by calcium imaging. Here, we present a highly reproducible technique to devise neuronal networks in vitro with a predefined connectivity induced by the design of the gateway. Daisy-chained neuronal networks with predefined connectivity and functional polarity were produced using the presented micropatterning method. Controlling the direction of signal propagation among populations of neurons provides insights to network communication and offers the chance to investigate more about learning processes in networks by external manipulation of cells and signal cascades. PMID:27379230

  4. Isolation of sensory neurons of Aplysia californica for patch clamp recordings of glutamatergic currents.

    PubMed

    Fieber, Lynne A; Carlson, Stephen L; Kempsell, Andrew T; Greer, Justin B; Schmale, Michael C

    2013-07-10

    The marine gastropod mollusk Aplysia californica has a venerable history as a model of nervous system function, with particular significance in studies of learning and memory. The typical preparations for such studies are ones in which the sensory and motoneurons are left intact in a minimally dissected animal, or a technically elaborate neuronal co-culture of individual sensory and motoneurons. Less common is the isolated neuronal preparation in which small clusters of nominally homogeneous neurons are dissociated into single cells in short term culture. Such isolated cells are useful for the biophysical characterization of ion currents using patch clamp techniques, and targeted modulation of these conductances. A protocol for preparing such cultures is described. The protocol takes advantage of the easily identifiable glutamatergic sensory neurons of the pleural and buccal ganglia, and describes their dissociation and minimal maintenance in culture for several days without serum.

  5. Defining modulatory inputs into CNS neuronal subclasses by functional pharmacological profiling

    PubMed Central

    Raghuraman, Shrinivasan; Garcia, Alfredo J.; Anderson, Tatiana M.; Twede, Vernon D.; Curtice, Kigen J.; Chase, Kevin; Ramirez, Jan-Marino; Olivera, Baldomero M.; Teichert, Russell W.

    2014-01-01

    Previously we defined neuronal subclasses within the mouse peripheral nervous system using an experimental strategy called “constellation pharmacology.” Here we demonstrate the broad applicability of constellation pharmacology by extending it to the CNS and specifically to the ventral respiratory column (VRC) of mouse brainstem, a region containing the neuronal network controlling respiratory rhythm. Analysis of dissociated cells from this locus revealed three major cell classes, each encompassing multiple subclasses. We broadly analyzed the combinations (constellations) of receptors and ion channels expressed within VRC cell classes and subclasses. These were strikingly different from the constellations of receptors and ion channels found in subclasses of peripheral neurons from mouse dorsal root ganglia. Within the VRC cell population, a subset of dissociated neurons responded to substance P, putatively corresponding to inspiratory pre-Bötzinger complex (preBötC) neurons. Using constellation pharmacology, we found that these substance P-responsive neurons also responded to histamine, and about half responded to bradykinin. Electrophysiological studies conducted in brainstem slices confirmed that preBötC neurons responsive to substance P exhibited similar responsiveness to bradykinin and histamine. The results demonstrate the predictive utility of constellation pharmacology for defining modulatory inputs into specific neuronal subclasses within central neuronal networks. PMID:24733934

  6. Dissociated lower limb muscle involvement in amyotrophic lateral sclerosis.

    PubMed

    Simon, Neil G; Lee, Michael; Bae, Jong Seok; Mioshi, Eneida; Lin, Cindy S-Y; Pfluger, Casey M; Henderson, Robert D; Vucic, Steve; Swash, Michael; Burke, David; Kiernan, Matthew C

    2015-06-01

    It has been suggested that corticomotoneuronal drive to ankle dorsiflexors is greater than to ankle plantar flexor muscles, despite the finding that plantar flexors are no less active than TA during walking and standing. The present study was undertaken to determine whether there was differential involvement of distal lower limb muscles in amyotrophic lateral sclerosis (ALS), to elucidate pathophysiological mechanisms of selective muscle involvement. Prospective studies were undertaken in 52 ALS patients, including clinical assessment, disease staging (revised ALS functional rating scale), Medical Research Council sum score, and a scale of upper motor neurone (UMN) dysfunction. Motor unit number estimates (MUNE) and compound muscle action potentials (CMAP) from ankle dorsiflexors and plantar flexors were used to provide objective measures. A novel 'split leg index' was calculated as follows: SLI = CMAPDF ÷ CMAPPF. In ALS, there was significantly greater reduction of MUNE and CMAP amplitude recorded from plantar flexors when compared to dorsiflexors, suggesting preferential involvement of plantar flexor muscles, underpinning a 'split leg' appearance. The SLI correlated with clinical plantar flexor strength (R= -0.56, p < 0.001). In no patient did the SLI suggest preferential dorsiflexor involvement. In subgroup analyses, mean SLI was greatest in lower limb-onset ALS. In conclusion, the present study has established dissociated involvement of muscles acting around the ankle in ALS. We suggest this reflects underlying differences in cortical, descending or local spinal modulation of these muscles.

  7. Leptin influences the excitability of area postrema neurons.

    PubMed

    Smith, Pauline M; Brzezinska, Paulina; Hubert, Fabien; Mimee, Andrea; Maurice, Donald H; Ferguson, Alastair V

    2016-03-01

    The area postrema (AP) is a circumventricular organ with important roles in central autonomic regulation. This medullary structure has been shown to express the leptin receptor and has been suggested to have a role in modulating peripheral signals, indicating energy status. Using RT-PCR, we have confirmed the presence of mRNA for the leptin receptor, ObRb, in AP, and whole cell current-clamp recordings from dissociated AP neurons demonstrated that leptin influenced the excitability of 51% (42/82) of AP neurons. The majority of responsive neurons (62%) exhibited a depolarization (5.3 ± 0.7 mV), while the remaining affected cells (16/42) demonstrated hyperpolarizing effects (-5.96 ± 0.95 mV). Amylin was found to influence the same population of AP neurons. To elucidate the mechanism(s) of leptin and amylin actions in the AP, we used fluorescence resonance energy transfer (FRET) to determine the effect of these peptides on cAMP levels in single AP neurons. Leptin and amylin were found to elevate cAMP levels in the same dissociated AP neurons (leptin: % total FRET response 25.3 ± 4.9, n = 14; amylin: % total FRET response 21.7 ± 3.1, n = 13). When leptin and amylin were coapplied, % total FRET response rose to 53.0 ± 8.3 (n = 6). The demonstration that leptin and amylin influence a subpopulation of AP neurons and that these two signaling molecules have additive effects on single AP neurons to increase cAMP, supports a role for the AP as a central nervous system location at which these circulating signals may act through common intracellular signaling pathways to influence central control of energy balance.

  8. Dissociated sequential activity and stimulus encoding in the dorsomedial striatum during spatial working memory

    PubMed Central

    Akhlaghpour, Hessameddin; Wiskerke, Joost; Choi, Jung Yoon; Taliaferro, Joshua P; Au, Jennifer; Witten, Ilana B

    2016-01-01

    Several lines of evidence suggest that the striatum has an important role in spatial working memory. The neural dynamics in the striatum have been described in tasks with short delay periods (1–4 s), but remain largely uncharacterized for tasks with longer delay periods. We collected and analyzed single unit recordings from the dorsomedial striatum of rats performing a spatial working memory task with delays up to 10 s. We found that neurons were activated sequentially, with the sequences spanning the entire delay period. Surprisingly, this sequential activity was dissociated from stimulus encoding activity, which was present in the same neurons, but preferentially appeared towards the onset of the delay period. These observations contrast with descriptions of sequential dynamics during similar tasks in other brains areas, and clarify the contribution of the striatum to spatial working memory. DOI: http://dx.doi.org/10.7554/eLife.19507.001 PMID:27636864

  9. Single-neuron NMDA receptor phenotype influences neuronal rewiring and reintegration following traumatic injury.

    PubMed

    Patel, Tapan P; Ventre, Scott C; Geddes-Klein, Donna; Singh, Pallab K; Meaney, David F

    2014-03-19

    Alterations in the activity of neural circuits are a common consequence of traumatic brain injury (TBI), but the relationship between single-neuron properties and the aggregate network behavior is not well understood. We recently reported that the GluN2B-containing NMDA receptors (NMDARs) are key in mediating mechanical forces during TBI, and that TBI produces a complex change in the functional connectivity of neuronal networks. Here, we evaluated whether cell-to-cell heterogeneity in the connectivity and aggregate contribution of GluN2B receptors to [Ca(2+)]i before injury influenced the functional rewiring, spontaneous activity, and network plasticity following injury using primary rat cortical dissociated neurons. We found that the functional connectivity of a neuron to its neighbors, combined with the relative influx of calcium through distinct NMDAR subtypes, together contributed to the individual neuronal response to trauma. Specifically, individual neurons whose [Ca(2+)]i oscillations were largely due to GluN2B NMDAR activation lost many of their functional targets 1 h following injury. In comparison, neurons with large GluN2A contribution or neurons with high functional connectivity both independently protected against injury-induced loss in connectivity. Mechanistically, we found that traumatic injury resulted in increased uncorrelated network activity, an effect linked to reduction of the voltage-sensitive Mg(2+) block of GluN2B-containing NMDARs. This uncorrelated activation of GluN2B subtypes after injury significantly limited the potential for network remodeling in response to a plasticity stimulus. Together, our data suggest that two single-cell characteristics, the aggregate contribution of NMDAR subtypes and the number of functional connections, influence network structure following traumatic injury.

  10. Somatodendritic and excitatory postsynaptic distribution of neuron-type dystrophin isoform, Dp40, in hippocampal neurons

    SciTech Connect

    Fujimoto, Takahiro; Itoh, Kyoko Yaoi, Takeshi; Fushiki, Shinji

    2014-09-12

    Highlights: • Identification of dystrophin (Dp) shortest isoform, Dp40, is a neuron-type Dp. • Dp40 expression is temporally and differentially regulated in comparison to Dp71. • Somatodendritic and nuclear localization of Dp40. • Dp40 is localized to excitatory postsynapses. • Dp40 might play roles in dendritic and synaptic functions. - Abstract: The Duchenne muscular dystrophy (DMD) gene produces multiple dystrophin (Dp) products due to the presence of several promoters. We previously reported the existence of a novel short isoform of Dp, Dp40, in adult mouse brain. However, the exact biochemical expression profile and cytological distribution of the Dp40 protein remain unknown. In this study, we generated a polyclonal antibody against the NH{sub 2}-terminal region of the Dp40 and identified the expression profile of Dp40 in the mouse brain. Through an analysis using embryonic and postnatal mouse cerebrums, we found that Dp40 emerged from the early neonatal stages until adulthood, whereas Dp71, an another Dp short isoform, was highly detected in both prenatal and postnatal cerebrums. Intriguingly, relative expressions of Dp40 and Dp71 were prominent in cultured dissociated neurons and non-neuronal cells derived from mouse hippocampus, respectively. Furthermore, the immunocytological distribution of Dp40 was analyzed in dissociated cultured neurons, revealing that Dp40 is detected in the soma and its dendrites, but not in the axon. It is worthy to note that Dp40 is localized along the subplasmalemmal region of the dendritic shafts, as well as at excitatory postsynaptic sites. Thus, Dp40 was identified as a neuron-type Dp possibly involving dendritic and synaptic functions.

  11. Comparing the symptoms and mechanisms of "dissociation" in dissociative identity disorder and borderline personality disorder.

    PubMed

    Laddis, Andreas; Dell, Paul F; Korzekwa, Marilyn

    2017-01-01

    A total of 75 patients were diagnosed with the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised as having dissociative identity disorder (DID), and 100 patients were diagnosed with the Structured Interview for DSM-IV Personality as having borderline personality disorder (BPD). Both groups were administered the Multidimensional Inventory of Dissociation (MID). DID patients had significantly higher MID scores than BPD patients, different distributions of MID scores, and different MID subscale profiles in 3 ranges of MID scores (0-15, 15-30, 30-45). The core MID symptoms-exhibited at all ranges of MID scores-for DID patients (the presence of alters, identity confusion, and memory problems) and BPD patients (flashbacks, identity confusion, and memory problems) were ostensibly similar but were considered to be mostly produced by different underlying processes. Multiple regression analyses showed that the core MID symptoms of DID patients had different predictors than did the core MID symptoms of BPD patients. Alter identities seemed to generate most-but not all-dissociative phenomena in DID patients, whereas only the 24% highest scoring BPD patients (MID ≥45) seemed to manifest alter-driven dissociative experiences. Most BPD dissociative experiences appeared to be due to 5 other mechanisms: (a) BPD-specific, stress-driven, rapid shifts of self-state; (b and c) nondefensive disruptions of the framework of perceptual organization with or without an accompanying BPD-specific, dissociation-like disintegration of affective/neurocognitive functioning; (d) a defensive distancing or detachment from distress (i.e., simple depersonalization); and (e) Allen, Console, and Lewis's (1999) severe absorptive detachment.

  12. Intensity dependence of multiphoton dissociation in formaldehyde

    NASA Astrophysics Data System (ADS)

    Koren, G.

    1980-01-01

    The paper reports a new intensity-dependent measurement of multiple-photon dissociation (MPD) in H2CO, HDCO, and D2CO gases using an intense pulsed CO2 TEA laser. In this measurement the energy and duration of the laser pulses are constant, and the intensity is varied by irradiating the sample with concave mirrors of different focal lengths. A model calculation is used to analyze and fit the MPD data of HDCO and D2CO which assumes that dissociation is obtained by a repeated mechanism in which coherent multiphoton excitation (CME) of the molecule to high vibration-rotation states is followed by intramolecular transfer of the excitation energy (ITEE) to the other molecule modes. It is concluded that the results are consistent with the absorption of 14 plus or minus 4 and 17 plus or minus 5 photons per molecule of HDCO and D2CO, respectively.

  13. Vibrational relaxation and dissociation in nitrogen

    NASA Technical Reports Server (NTRS)

    Varghese, Philip L.; Gonzales, David A.

    1991-01-01

    Calculations of the vibrational and dissociation transition probabilities are made for N2-N2 and N2-N collisions by means of a semiclassical N-state approximation. The flaws in previous techniques are reviewed, with special attention given to the prediction of overtones. The method presented ignores the effects of molecular rotation and employs a revised extended Rydberg intermolecular potential to describe diatom-diatom and diatom-atom collisions. The collision velocities investigated exhibit probabilities of less than unity by means of the N-state method. The continuum is quantized to treat dissociation, and the collision results demonstrate probability enhancements for V-V-T transitions in both bound-bound and bound-free transitions. The technique is of particular interest for the theoretical modeling of reentry flows such as those encountered in aerobraking maneuvers.

  14. Fluid hydrogen at high density - Pressure dissociation

    NASA Technical Reports Server (NTRS)

    Saumon, Didier; Chabrier, Gilles

    1991-01-01

    A model for the Helmholtz free energy of fluid hydrogen at high density and high temperature is developed. This model aims at describing both pressure and temperature dissociation and ionization and bears directly on equations of state of partially ionized plasmas, as encountered in astrophysical situations and high-pressure experiments. This paper focuses on a mixture of hydrogen atoms and molecules and is devoted to the study of the phenomenon of pressure dissociation at finite temperatures. In the present model, the strong interactions are described with realistic potentials and are computed with a modified Weeks-Chandler-Andersen fluid perturbation theory that reproduces Monte Carlo simulations to better than 3 percent. Theoretical Hugoniot curves derived from the model are in excellent agreement with experimental data.

  15. The charmonium dissociation in an ''anomalous wind''

    SciTech Connect

    Sadofyev, Andrey V.; Yin, Yi

    2016-01-11

    We study the charmonium dissociation in a strongly coupled chiral plasma in the presence of magnetic field and axial charge imbalance. This type of plasma carries "anomalous flow" induced by the chiral anomaly and exhibits novel transport phenomena such as chiral magnetic effect. We found that the "anomalous flow" would modify the charmonium color screening length by using the gauge/gravity correspondence. We derive an analytical expression quantifying the "anomalous flow" experienced by a charmonium for a large class of chiral plasma with a gravity dual. We elaborate on the similarity and it qualitative difference between anomalous effects on the charmonium color screening length which are model-dependent and those on the heavy quark drag force which are fixed by the second law of thermodynamics. As a result, we speculate on the possible charmonium dissociation induced by the chiral anomaly in heavy ion collisions.

  16. The charmonium dissociation in an ''anomalous wind''

    DOE PAGES

    Sadofyev, Andrey V.; Yin, Yi

    2016-01-11

    We study the charmonium dissociation in a strongly coupled chiral plasma in the presence of magnetic field and axial charge imbalance. This type of plasma carries "anomalous flow" induced by the chiral anomaly and exhibits novel transport phenomena such as chiral magnetic effect. We found that the "anomalous flow" would modify the charmonium color screening length by using the gauge/gravity correspondence. We derive an analytical expression quantifying the "anomalous flow" experienced by a charmonium for a large class of chiral plasma with a gravity dual. We elaborate on the similarity and it qualitative difference between anomalous effects on the charmoniummore » color screening length which are model-dependent and those on the heavy quark drag force which are fixed by the second law of thermodynamics. As a result, we speculate on the possible charmonium dissociation induced by the chiral anomaly in heavy ion collisions.« less

  17. Vibration dissociation coupling in nonequilibrium flows

    NASA Technical Reports Server (NTRS)

    Candler, Graham V.

    1992-01-01

    The final report on research between North Carolina State University and the NASA Ames Research Center is presented. The research was aimed at using the Schwartz, Slawsky, Herzfeld (SSH) theory to simulate the vibrational relaxation of nitrogen molecules undergoing dissociation or recombination over a wide range of conditions. The results of these simulations were then treated as exact, and they were used to develop a model for the coupled vibration-dissociation process. This new model is simple enough to be used in computational fluid dynamics codes, but still captures the physics of the complex process. The model is used to simulate the flow over typical geometries to test it and to determine how much impact it has on the flow field. The key elements of this research are summarized.

  18. Theoretical dissociation energies for ionic molecules

    NASA Technical Reports Server (NTRS)

    Langhoff, S. R.; Bauschlicher, C. W., Jr.; Partridge, H.

    1986-01-01

    Ab initio calculations at the self-consistent-field and singles plus doubles configuration-interaction level are used to determine accurate spectroscopic parameters for most of the alkali and alkaline-earth fluorides, chlorides, oxides, sulfides, hydroxides, and isocyanides. Numerical Hartree-Fock (NHF) calculations are performed on selected systems to ensure that the extended Slater basis sets employed for the diatomic systems are near the Hartree-Fock limit. Extended Gaussian basis sets of at least triple-zeta plus double polarization equality are employed for the triatomic system. With this model, correlation effects are relatively small, but invariably increase the theoretical dissociation energies. The importance of correlating the electrons on both the anion and the metal is discussed. The theoretical dissociation energies are critically compared with the literature to rule out disparate experimental values. Theoretical (sup 2)Pi - (sup 2)Sigma (sup +) energy separations are presented for the alkali oxides and sulfides.

  19. The dissociation energy of N2

    NASA Technical Reports Server (NTRS)

    Almlof, Jan; Deleeuw, Bradley J.; Taylor, Peter R.; Bauschlicher, Charles W., Jr.; Siegbahn, Per

    1989-01-01

    The requirements for very accurate ab initio quantum chemical prediction of dissociation energies are examined using a detailed investigation of the nitrogen molecule. Although agreement with experiment to within 1 kcal/mol is not achieved even with the most elaborate multireference CI (configuration interaction) wave functions and largest basis sets currently feasible, it is possible to obtain agreement to within about 2 kcal/mol, or 1 percent of the dissociation energy. At this level it is necessary to account for core-valence correlation effects and to include up to h-type functions in the basis. The effect of i-type functions, the use of different reference configuration spaces, and basis set superposition error were also investigated. After discussing these results, the remaining sources of error in our best calculations are examined.

  20. Enactments and dissociations driven by cultural differences.

    PubMed

    Cohen, Etty

    2007-03-01

    Cultural differences between the analytic dyad can foster powerful transference-counter-transference feelings and potentially promote traumatic re-enactments. Those patients who are more directly affected by traumatic experiences may be able to verbalize what has happened to them only if they are convinced that their analysts are "taking in their horror, holding it for them, responding to it emotionally (reenacting) and giving it back in more modulated and containable" manner (Davies, 1997, p. 24). These mutual enactments that emerge in patients and their analysts can be understood as dissociated self-states. Clinical material is presented from the treatment of an African-American inner-city teenager and an Israeli teenage soldier to illustrate the emergence of enactments and dissociation in patient-analyst dyads.

  1. Dissociative Disorders: Between Neurosis and Psychosis

    PubMed Central

    Devillé, C.; Moeglin, C.; Sentissi, O.

    2014-01-01

    Dissociative disorders are a set of disorders defined by a disturbance affecting functions that are normally integrated with a prevalence of 2.4 percent in industrialised countries. These disorders are often poorly diagnosed or misdiagnosed because of sharing common clinical features with psychotic disorders, but requiring a very different trajectory of care. Repeated clinical situations in a crisis centre in Geneva provided us with a critical overview of current evidence of knowledge in clinical and etiopathological field about dissociative disorders. Because of their multiple expressions and the overlap with psychotic disorders, we focused on the clinical aspects using three different situations to better understand their specificity and to extend our thinking to the relevance of terms “neurosis” and “psychosis.” Finally, we hope that this work might help physicians and psychiatrists to become more aware of this complex set of disorders while making a diagnosis. PMID:25405051

  2. Dissociative disorders: between neurosis and psychosis.

    PubMed

    Devillé, C; Moeglin, C; Sentissi, O

    2014-01-01

    Dissociative disorders are a set of disorders defined by a disturbance affecting functions that are normally integrated with a prevalence of 2.4 percent in industrialised countries. These disorders are often poorly diagnosed or misdiagnosed because of sharing common clinical features with psychotic disorders, but requiring a very different trajectory of care. Repeated clinical situations in a crisis centre in Geneva provided us with a critical overview of current evidence of knowledge in clinical and etiopathological field about dissociative disorders. Because of their multiple expressions and the overlap with psychotic disorders, we focused on the clinical aspects using three different situations to better understand their specificity and to extend our thinking to the relevance of terms "neurosis" and "psychosis." Finally, we hope that this work might help physicians and psychiatrists to become more aware of this complex set of disorders while making a diagnosis.

  3. Synaptic connectivity in engineered neuronal networks.

    PubMed

    Molnar, Peter; Kang, Jung-Fong; Bhargava, Neelima; Das, Mainak; Hickman, James J

    2014-01-01

    We have developed a method to organize cells in dissociated cultures using engineered chemical clues on a culture surface and determined their connectivity patterns. Although almost all elements of the synaptic transmission machinery can be studied separately in single cell models in dissociated cultures, the complex physiological interactions between these elements are usually lost. Thus, factors affecting synaptic transmission are generally studied in organotypic cultures, brain slices, or in vivo where the cellular architecture generally remains intact. However, by utilizing engineered neuronal networks complex phenomenon such as synaptic transmission or synaptic plasticity can be studied in a simple, functional, cell culture-based system. We have utilized self-assembled monolayers and photolithography to create the surface templates. Embryonic hippocampal cells, plated on the resultant patterns in serum-free medium, followed the surface clues and formed the engineered neuronal networks. Basic whole-cell patch-clamp electrophysiology was applied to characterize the synaptic connectivity in these engineered two-cell networks. The same technology has been used to pattern other cell types such as cardiomyocytes or skeletal muscle fibers.

  4. Dopamine modulation of transient receptor potential vanilloid type 1 (TRPV1) receptor in dorsal root ganglia neurons

    PubMed Central

    Chakraborty, Saikat; Rebecchi, Mario; Kaczocha, Martin

    2016-01-01

    Key points Transient receptor potential vanilloid type 1 (TRPV1) receptors transduce noxious thermal stimuli and are responsible for the thermal hyperalgesia associated with inflammatory pain.A large population of dorsal root ganglia (DRG) neurons, including the C low threshold mechanoreceptors (C‐LTMRs), express tyrosine hydroxylase, and probably release dopamine.We found that dopamine and SKF 81297 (an agonist at D1/D5 receptors), but not quinpirole (an agonist at D2 receptors), downregulate the activity of TRPV1 channels in DRG neurons.The inhibitory effect of SKF 81297 on TRPV1 channels was strongly dependent on external calcium and preferentially linked to calcium–calmodulin‐dependent protein kinase II (CaMKII).We suggest that modulation of TRPV1 channels by dopamine in nociceptive neurons may represent a way for dopamine to modulate incoming noxious stimuli. Abstract The transient receptor potential vanilloid type 1 (TRPV1) receptor plays a key role in the modulation of nociceptor excitability. To address whether dopamine can modulate the activity of TRPV1 channels in nociceptive neurons, the effects of dopamine and dopamine receptor agonists were tested on the capsaicin‐activated current recorded from acutely dissociated small diameter (<27 μm) dorsal root ganglia (DRG) neurons. Dopamine or SKF 81297 (an agonist at D1/D5 receptors), caused inhibition of both inward and outward currents by ∼60% and ∼48%, respectively. The effect of SKF 81297 was reversed by SCH 23390 (an antagonist at D1/D5 receptors), confirming that it was mediated by activation of D1/D5 dopamine receptors. In contrast, quinpirole (an agonist at D2 receptors) had no significant effect on the capsaicin‐activated current. Inhibition of the capsaicin‐activated current by SKF 81297 was mediated by G protein coupled receptors (GPCRs), and highly dependent on external calcium. The inhibitory effect of SKF 81297 on the capsaicin‐activated current was not affected when

  5. The Bond Dissociation Energies of 1-Butene

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Langhoff, Stephen R. (Technical Monitor)

    1994-01-01

    The bond dissociation energies of 1-butene and several calibration systems are computed using the G2(MP2) approach. The agreement between the calibration systems and experiment is very good. The computed values for 1-butene are compared with calibration systems and the agreement between the computed results for 1-butene and the "rule of thumb" values from the smaller systems is remarkably good.

  6. Dynamics of dissociative electron attachment to ammonia

    NASA Astrophysics Data System (ADS)

    Rescigno, T. N.; Trevisan, C. S.; Orel, A. E.; Slaughter, D. S.; Adaniya, H.; Belkacem, A.; Weyland, Marvin; Dorn, Alexander; McCurdy, C. W.

    2016-05-01

    Ab initio theoretical studies and momentum-imaging experiments are combined to provide a consistent picture of the dynamics of dissociative electron attachment to ammonia through its 5.5- and 10.5-eV resonance channels. The present study clarifies the character and symmetry of the anion states involved and the dynamics that leads to the observed fragment-ion channels, their branching ratios, and angular distributions.

  7. Dissociative Recombination Chemistry and Plasma Dynamics

    DTIC Science & Technology

    2008-06-16

    the fractional square of product momentum with product momentum vectors . Qx and Qy denote the degenerate bend two-body dissociation limits...with product momentum vectors . Qx and Qy denote the degenerate bend normal modes for C2v symmetry H2D and HD2 isomers of H3. symmetry for the Qx...heavy (D atom) products in general receive a greater partitioning of energy than the light product. This may have important implications for

  8. Characteristics of GABAergic and cholinergic neurons in perinuclear zone of mouse supraoptic nucleus

    PubMed Central

    Ennis, Matthew; Szabó, Gábor; Armstrong, William E.

    2014-01-01

    The perinuclear zone (PNZ) of the supraoptic nucleus (SON) contains some GABAergic and cholinergic neurons thought to innervate the SON proper. In mice expressing enhanced green fluorescent protein (eGFP) in association with glutamate decarboxylase (GAD)65 we found an abundance of GAD65-eGFP neurons in the PNZ, whereas in mice expressing GAD67-eGFP, there were few labeled PNZ neurons. In mice expressing choline acetyltransferase (ChAT)-eGFP, large, brightly fluorescent and small, dimly fluorescent ChAT-eGFP neurons were present in the PNZ. The small ChAT-eGFP and GAD65-eGFP neurons exhibited a low-threshold depolarizing potential consistent with a low-threshold spike, with little transient outward rectification. Large ChAT-eGFP neurons exhibited strong transient outward rectification and a large hyperpolarizing spike afterpotential, very similar to that of magnocellular vasopressin and oxytocin neurons. Thus the large soma and transient outward rectification of large ChAT-eGFP neurons suggest that these neurons would be difficult to distinguish from magnocellular SON neurons in dissociated preparations by these criteria. Large, but not small, ChAT-eGFP neurons were immunostained with ChAT antibody (AB144p). Reconstructed neurons revealed a few processes encroaching near and passing through the SON from all types but no clear evidence of a terminal axon arbor. Large ChAT-eGFP neurons were usually oriented vertically and had four or five dendrites with multiple branches and an axon with many collaterals and local arborizations. Small ChAT-eGFP neurons had a more restricted dendritic tree compared with parvocellular GAD65 neurons, the latter of which had long thin processes oriented mediolaterally. Thus many of the characteristics found previously in unidentified, small PNZ neurons are also found in identified GABAergic neurons and in a population of smaller ChAT-eGFP neurons. PMID:25376783

  9. Potassium currents in isolated CA1 neurons of the rat after kindling epileptogenesis.

    PubMed

    Vreugdenhil, M; Wadman, W J

    1995-06-01

    Daily tetanic stimulation of the Schaffer collaterals generates an epileptogenic focus in area CA1 of the rat hippocampus, ultimately leading to generalized tonic-clonic convulsions (kindling). Potassium currents were measured under voltage-clamp conditions in pyramidal neurons, acutely dissociated from the focus of fully kindled rats, one day and six weeks after the last generalized seizure. Their amplitude, kinetics, voltage dependence and calcium dependence were compared with controls. With Ca2+ influx blocked by 0.5 mM Ni2+, the sustained current (delayed rectifier) and the transient current (A-current) were not different after kindling. Calcium influx evoked an additional fast transient current component. This transient calcium-dependent current component was increased by 154%, but only immediately after the seizure. A second, slow calcium-dependent potassium current component was dependent on the intracellular calcium level, set by the pipette as well as on calcium influx. The peak amplitude of this slow calcium-dependent current was under optimal calcium conditions not different after kindling, but we found indications that either calcium homeostasis or the calcium sensitivity of the potassium channels was affected by the kindling process. In contrast to the previously described enhancement of calcium current, kindling epileptogenesis did not change the total potassium current amplitude. The minor changes that were observed can be related either to changes in calcium current or to changes in intracellular calcium homeostasis.

  10. Electron induced dissociation of singly deprotonated peptides.

    PubMed

    Kalli, Anastasia; Grigorean, Gabriela; Håkansson, Kristina

    2011-12-01

    Dissociation of singly charged species is more challenging compared with that of multiply charged precursor ions because singly charged ions are generally more stable. In collision activated dissociation (CAD), singly charged ions also gain less kinetic energy in a fixed electric field compared with multiply charged species. Furthermore, ion-electron and ion-ion reactions that frequently provide complementary and more extensive fragmentation compared with CAD typically require multiply charged precursor ions. Here, we investigate electron induced dissociation (EID) of singly deprotonated peptides and compare the EID fragmentation patterns with those observed in negative ion mode CAD. Fragmentation induced upon electron irradiation and collisional activation is not specific and results in the formation of a wide range of product ions, including b-, y-, a-, x-, c-, and z-type ions. Characteristic amino acid side chain losses are detected in both techniques. However, differences are also observed between EID and CAD spectra of the same species, including formation of odd-electron species not seen in CAD, in EID. Furthermore, EID frequently results in more extensive fragmentation compared with CAD. For modified peptides, EID resulted in retention of sulfonation and phosphorylation, allowing localization of the modification site. The observed differences are likely due to both vibrational and electronic excitation in EID, whereas only the former process occurs in CAD.

  11. Spontaneous dissociation of bipolar hip hemiarthroplasty in a patient with nerve palsy: A case report and review of the literature

    PubMed Central

    Yuenyongviwat, Varah; Iamthanaporn, Khanin; Hongnaparak, Theerawit

    2015-01-01

    Introduction Dislocation after bipolar hemiarthroplasty is a common complication but dissociation of the prosthesis is rare. There are some reports of bipolar hemiarthroplasty dissociation at the inner head and outer shell. However, there are limited reports on acute spontaneous dissociation of the head and neck at the taper interface in bipolar hemiarthroplasty. Presentation of case A 65-year-old female had cemented bipolar hemi hip replacement after fixation failure of a dynamic hip screw. She had left lower limb weakness for ten years after previous spinal surgery. At the sixth week of postoperation, the patient had dissociation of the components of the bipolar hemiarthroplasty at the femoral head and neck junction. The patient had open reduction and femoral head revision. There was no re-dislocation at one-year follow-up. Discussion Dissociation of bipolar hemiarthroplasty is a complex complication that can happen from the modularity of the implant. This condition requires operative treatment. The mechanism and cause of failure should be identified before the operation. Conclusion To prevent this condition, preoperative planning and proper techniques should be done as an index procedure. In the case of marked shortening of the limb after an operation in patients with lower limb muscle weakness, we hypothesize that early full weight bearing with immediate use of a shoe lift might help prevent this condition. PMID:26339788

  12. Prevalence of dissociative disorders among women in the general population.

    PubMed

    Sar, Vedat; Akyüz, Gamze; Doğan, Orhan

    2007-01-15

    This study sought to determine the prevalence of dissociative disorders among women in the general population, as assessed in a representative sample of a city in central Turkey. The Dissociative Disorders Interview Schedule (DDIS), the Borderline Personality Disorder section of the Structured Clinical Interview for DSM-III-R Personality Disorders (SCID-II), and the PTSD-Module of the Structured Clinical Interview for DSM-III-R (SCID) were administered to 628 women in 500 homes. The mean age of participants was 34.8 (S.D.=11.5, range: 18-65); 18.3% of participants (n=115) had a lifetime diagnosis of a dissociative disorder. Dissociative disorder not otherwise specified (DDNOS) was the most prevalent diagnosis (8.3%); 1.1% of the population was diagnosed as having dissociative identity disorder (DID). Participants with a dissociative disorder had borderline personality disorder, somatization disorder, major depression, PTSD, and history of suicide attempt more frequently than did participants without a dissociative disorder. Childhood sexual abuse, physical neglect, and emotional abuse were significant predictors of a dissociative disorder diagnosis. Only 28.7% of the dissociative participants had received psychiatric treatment previously. Because dissociative disorders are trauma-related, significant part of the adult clinical consequences of childhood trauma remains obscure in the minds of mental health professionals and of the overall community. Revisions in diagnostic criteria of dissociative disorders in the DSM-IV are recommended.

  13. Dissociative disorders among Chinese inpatients diagnosed with schizophrenia.

    PubMed

    Yu, Junhan; Ross, Colin A; Keyes, Benjamin B; Li, Ying; Dai, Yunfei; Zhang, Tianhong; Wang, Lanlan; Fan, Qing; Xiao, Zeping

    2010-01-01

    The purpose of this study was to assess the prevalence of dissociative disorders in a sample of Chinese psychiatric inpatients. Participants in the study were 569 consecutively admitted inpatients at Shanghai Mental Health Center, China, of whom 84.9% had a clinical diagnosis of schizophrenia based on the Chinese Classification and Diagnostic Criteria of Mental Disorders, Version 3. All participants completed a self-report measure of dissociation (the Dissociative Experiences Scale), and none had a prior diagnosis of a dissociative disorder. A total of 96 randomly selected participants were interviewed with a structured interview (the Dissociative Disorders Interview Schedule) and a clinical interview. These 96 patients did not differ significantly from the 473 patients who were not interviewed on any demographic measures or who did not complete the self-report dissociation measure. A total of 28 patients (15.3%, after weighting of the data) received a clinical diagnosis of a dissociative disorder based on Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.) criteria. Dissociative identity disorder was diagnosed in 2 patients (0.53%, after weighting). Compared to the patients without a dissociative disorder, patients with dissociative disorders were significantly more likely to report childhood abuse (57.1% vs. 22.1%), but the 2 groups did not differ significantly on any demographic measures. Dissociative disorders were readily identified in an inpatient psychiatric population in China.

  14. Dissociative Disorders Among Chinese Inpatients Diagnosed With Schizophrenia

    PubMed Central

    Yu, Junhan; Ross, Colin A.; Keyes, Benjamin B.; Li, Ying; Dai, Yunfei; Zhang, Tianhong; Wang, Lanlan; Fan, Qing; Xiao, Zeping

    2010-01-01

    The purpose of the study was to assess the prevalence of dissociative disorders in a sample of Chinese psychiatric inpatients. Participants in the study consisted of 569 consecutively admitted inpatients at Shanghai Mental Health Center, China, of whom 84.9% had a clinical diagnosis of schizophrenia based on the Chinese Classification and Diagnostic Criteria for Mental Disorders, Version 3 (CCMD-3). All participants completed a self-report measure of dissociation, the Dissociative Experiences Scale (DES) and none had a prior diagnosis of a dissociative disorder. Ninety-six randomly selected participants were interviewed with a structured interview, the Dissociative Disorders Interview Schedule (DDIS) and a clinical interview. These 96 patients did not differ significantly from the 473 patients who were not interviewed on any demographic measures or on the self-report measure dissociation. A total of 28 (15.3%, after weighting of the data) patients received a clinical diagnosis of a dissociative disorder based on DSM-IV-TR criteria. Dissociative identity disorder was diagnosed in 2 (0.53%, after weighting) patients. Compared to the patients without a dissociative disorder, patients with dissociative disorders were significantly more likely to report childhood abuse (57.1% versus 22.1%), but the two groups did not differ significantly on any demographic measures. Dissociative disorders were readily identified in an inpatient psychiatric population in China. PMID:20603768

  15. Detachment, compartmentalization, and schizophrenia: linking dissociation and psychosis by subtype.

    PubMed

    Vogel, Matthias; Braungardt, Tanja; Grabe, Hans Jörgen; Schneider, Wolfgang; Klauer, Thomas

    2013-01-01

    To explain the phenomenological overlap between dissociation and schizophrenia, a dissociative subtype of schizophrenia has been proposed as a possibility. Dissociation is often believed to be organized on a continuum, although 2 qualitatively different phenomena can be distinguished in theory, research, and clinical practice: (a) states of separation from self or environment (detachment dissociation) and (b) inaccessibility of normally accessible mental contents (compartmentalization dissociation). This study used the Positive and Negative Syndrome Scale (PANSS) and the Association for Methodology and Documentation in Psychiatry module for the interview assessment of dissociation to investigate the relationships between PANSS subscales, detachment dissociation, and compartmentalization dissociation in a sample of 72 patients with schizophrenia. A confirmatory factor analysis sustained the bipartite model, yielding factors that grouped dissociative items around amnesia and depersonalization/derealization. The latter factor also contained identity disturbances and was therefore not entirely consistent with the theoretical formulations of detachment dissociation. It is important to note that the structure of those factors may be influenced by the symptoms of schizophrenia to which they were specifically linked: The factor containing depersonalization/derealization was connected to the positive symptoms subscale of the PANSS, whereas the factor containing amnesia was associated with the negative subscale. Hence, a dichotomy of dissociation is confirmed inasmuch as its subtypes are as distinguishable as PANSS subscales. This has implications on theoretical and clinical levels.

  16. Teaching Chinese psychiatrists to make reliable dissociative disorder diagnoses.

    PubMed

    Fan, Qing; Yu, Junhan; Ross, Colin A; Keyes, Benjamin B; Dai, Yunfei; Zhang, Tianhong; Wang, Lanlan; Xiao, Zeping

    2011-09-01

    The aim of the study was to assess the outcome of an educational effort by two North American experts in dissociative disorders to teach Chinese psychiatrists to make reliable dissociative disorder diagnoses. In the final phase of the educational effort, 569 patients at Shanghai Mental Health Center completed the Chinese version of the Dissociative Experiences Scale (DES). Patients were then randomly selected in different proportions according to their DES scores: 96 selected patients were then assessed with the Dissociative Disorders Interview Schedule (DDIS) and clinical diagnostic interviews based on DSM-IV criteria. According to the clinical diagnostic interviews, 28 (4.9%) patients were diagnosed as having dissociative disorders. Agreement between the American experts and Chinese psychiatrists for presence or absence of a dissociative disorder was 0.75 using Cohen's kappa. Dissociative disorders can be diagnosed in China with good inter-rater reliability. The authors describe the steps taken to achieve this outcome.

  17. Cognitive Processes in Dissociation: Comment on Giesbrecht et al. (2008)

    PubMed Central

    Bremner, J. Douglas

    2010-01-01

    In “Cognitive Processes in Dissociation: An Analysis of Core Theoretical Assumptions,” published in Psychological Bulletin, Giesbrecht, Lynn, Lilienfeld, and Merckelbach (2008) have challenged the widely accepted trauma theory of dissociation, which holds that dissociative symptoms are caused by traumatic stress. In doing so the authors outline a series of links between various constructs, such as fantasy proneness, cognitive failures, absorption, suggestibility, altered information-processing, dissociation, and amnesia, claiming that these linkages lead to the false conclusion that trauma causes dissociation. A review of the literature, however, shows that these are not necessarily related constructs. Careful examination of their arguments reveals no basis for the conclusion that there is no association between trauma and dissociation. The current comment offers a critical review and rebuttal of the argument of Giesbrecht et al. that there is no relationship between trauma and dissociation. PMID:20063920

  18. Does trauma-linked dissociation vary across ethnic groups?

    PubMed

    Zatzick, D F; Marmar, C R; Weiss, D S; Metzler, T

    1994-10-01

    This investigation assessed the relationship between traumatic stress exposure and dissociation in male Vietnam theater veterans from three ethnic groups. Subjects were African-American (N = 61), Caucasian (N = 91), and Hispanic (N = 73) veterans who completed the Dissociative Experience Scale and a measure of war zone stress exposure, and who were rated on the Peritraumatic Dissociative Experiences Questionnaire-Rater Version. Greater exposure to war zone stress was associated with reports of more dissociation at the time of trauma and with more general dissociative experiences both when the data were pooled and when examined separately for each group. After controlling for the effects of war zone stress exposure, the significant differences found in peritraumatic and general dissociative experiences across the three ethnic groups no longer were evident. This investigation demonstrated that among American Vietnam veterans, greater exposure to traumatic stress is related to more dissociative experiences, regardless of ethnicity.

  19. Acute Bronchitis

    MedlinePlus

    ... can also cause acute bronchitis. To diagnose acute bronchitis, your health care provider will ask about your symptoms and listen to your breathing. You may also have other tests. Treatments include rest, fluids, and aspirin (for adults) or ...

  20. Ab initio calculations of dissociative attachment and dissociative recombination of electrons and polyatomic species

    NASA Astrophysics Data System (ADS)

    Haxton, Daniel

    2009-05-01

    Interactions of free electrons with neutral and positively charged molecular species play a role in various physical systems. In interstellar space, reactions such as dissociative recombination determine the balance of various charged and neutral species. In a laboratory equipped with an apparatus like a COLTRIMS device, the dissociative attachment process can be used as a microscope to study polyatomic molecular dynamics. We discuss the theoretical and numerical methods used to calculate dissociative attachment and dissociative recombination of electrons with larger molecules from first principles. Studies using these methods are complimentary to other methods that yield more approximate reaction rates at greatly lesser numerical cost; they may yield precise information about the dissociation dynamics, product distribution, and differential cross section that approximate methods cannot. We discuss calculations performed to date on the target species H2O, NO2, and LiH2^+. We discuss the scaling of our numerical methods with the number of atoms, and the prospects of applying them to tetra-atomics.

  1. Zero-Point Energy Constraint for Unimolecular Dissociation Reactions. Giving Trajectories Multiple Chances To Dissociate Correctly.

    PubMed

    Paul, Amit K; Hase, William L

    2016-01-28

    A zero-point energy (ZPE) constraint model is proposed for classical trajectory simulations of unimolecular decomposition and applied to CH4* → H + CH3 decomposition. With this model trajectories are not allowed to dissociate unless they have ZPE in the CH3 product. If not, they are returned to the CH4* region of phase space and, if necessary, given additional opportunities to dissociate with ZPE. The lifetime for dissociation of an individual trajectory is the time it takes to dissociate with ZPE in CH3, including multiple possible returns to CH4*. With this ZPE constraint the dissociation of CH4* is exponential in time as expected for intrinsic RRKM dynamics and the resulting rate constant is in good agreement with the harmonic quantum value of RRKM theory. In contrast, a model that discards trajectories without ZPE in the reaction products gives a CH4* → H + CH3 rate constant that agrees with the classical and not quantum RRKM value. The rate constant for the purely classical simulation indicates that anharmonicity may be important and the rate constant from the ZPE constrained classical trajectory simulation may not represent the complete anharmonicity of the RRKM quantum dynamics. The ZPE constraint model proposed here is compared with previous models for restricting ZPE flow in intramolecular dynamics, and connecting product and reactant/product quantum energy levels in chemical dynamics simulations.

  2. In vitro analysis of human immunodeficiency virus particle dissociation: gag proteolytic processing influences dissociation kinetics.

    PubMed

    Müller, Barbara; Anders, Maria; Reinstein, Jochen

    2014-01-01

    Human immunodeficiency virus particles undergo a step of proteolytic maturation, in which the main structural polyprotein Gag is cleaved into its mature subunits matrix (MA), capsid (CA), nucleocapsid (NC) and p6. Gag proteolytic processing is accompanied by a dramatic structural rearrangement within the virion, which is necessary for virus infectivity and has been proposed to proceed through a sequence of dissociation and reformation of the capsid lattice. Morphological maturation appears to be tightly regulated, with sequential cleavage events and two small spacer peptides within Gag playing important roles by regulating the disassembly of the immature capsid layer and formation of the mature capsid lattice. In order to measure the influence of individual Gag domains on lattice stability, we established Förster's resonance energy transfer (FRET) reporter virions and employed rapid kinetic FRET and light scatter measurements. This approach allowed us to measure dissociation properties of HIV-1 particles assembled in eukaryotic cells containing Gag proteins in different states of proteolytic processing. While the complex dissociation behavior of the particles prevented an assignment of kinetic rate constants to individual dissociation steps, our analyses revealed characteristic differences in the dissociation properties of the MA layer dependent on the presence of additional domains. The most striking effect observed here was a pronounced stabilization of the MA-CA layer mediated by the presence of the 14 amino acid long spacer peptide SP1 at the CA C-terminus, underlining the crucial role of this peptide for the resolution of the immature particle architecture.

  3. Reelin transiently promotes N-cadherin-dependent neuronal adhesion during mouse cortical development.

    PubMed

    Matsunaga, Yuki; Noda, Mariko; Murakawa, Hideki; Hayashi, Kanehiro; Nagasaka, Arata; Inoue, Seika; Miyata, Takaki; Miura, Takashi; Kubo, Ken-Ichiro; Nakajima, Kazunori

    2017-02-21

    Reelin is an essential glycoprotein for the establishment of the highly organized six-layered structure of neurons of the mammalian neocortex. Although the role of Reelin in the control of neuronal migration has been extensively studied at the molecular level, the mechanisms underlying Reelin-dependent neuronal layer organization are not yet fully understood. In this study, we directly showed that Reelin promotes adhesion among dissociated neocortical neurons in culture. The Reelin-mediated neuronal aggregation occurs in an N-cadherin-dependent manner, both in vivo and in vitro. Unexpectedly, however, in a rotation culture of dissociated neocortical cells that gradually reaggregated over time, we found that it was the neural progenitor cells [radial glial cells (RGCs)], rather than the neurons, that tended to form clusters in the presence of Reelin. Mathematical modeling suggested that this clustering of RGCs could be recapitulated if the Reelin-dependent promotion of neuronal adhesion were to occur only transiently. Thus, we directly measured the adhesive force between neurons and N-cadherin by atomic force microscopy, and found that Reelin indeed enhanced the adhesiveness of neurons to N-cadherin; this enhanced adhesiveness began to be observed at 30 min after Reelin stimulation, but declined by 3 h. These results suggest that Reelin transiently (and not persistently) promotes N-cadherin-mediated neuronal aggregation. When N-cadherin and stabilized β-catenin were overexpressed in the migrating neurons, the transfected neurons were abnormally distributed in the superficial region of the neocortex, suggesting that appropriate regulation of N-cadherin-mediated adhesion is important for correct positioning of the neurons during neocortical development.

  4. Dissociative depression among women with fibromyalgia or rheumatoid arthritis.

    PubMed

    Kilic, Ozge; Sar, Vedat; Taycan, Okan; Aksoy-Poyraz, Cana; Erol, Turgut C; Tecer, Ozlem; Emul, Murat H; Ozmen, Mine

    2014-01-01

    The aim of this study was to inquire about the possible relations of childhood trauma, anger, and dissociation to depression among women with fibromyalgia or rheumatoid arthritis. Fifty female patients diagnosed as having fibromyalgia (n = 30) or rheumatoid arthritis (n = 20) participated in the study. The Childhood Trauma Questionnaire, Somatoform Dissociation Questionnaire (SDQ), Dissociation Questionnaire (DIS-Q), Beck Depression Inventory (BDI), Spielberger State-Trait Anger Expression Inventory, and Dissociative Disorders Interview Schedule were administered to all participants. Women with a lifetime diagnosis of depressive disorder had higher scores for somatoform and psychoform dissociation than the nondepressive patients. However, childhood trauma scores did not differ between the 2 groups. In regression analysis, current severity of depression (BDI) was predicted by psychoform dissociation (DIS-Q) and lower education, and lifetime diagnosis of major depression was predicted by somatoform dissociation (SDQ). Whereas childhood emotional neglect predicted somatoform dissociation, psychoform dissociation was predicted by childhood sexual abuse. Mental processing of anger seems to be 1 of the dimensions of psychodynamics in trauma-related depressive conditions. In the context of the perceived threat of loss of control due to expressed anger and mental disintegration, somatoform dissociation seems to contribute to overmodulation of emotions in dissociative depression. Among patients suffering from physical illness with possible psychosomatic dimensions, assessment of somatoform dissociation in addition to psychoform dissociation may be helpful to understand diverse psychopathological trajectories emerging in the aftermath of childhood adversities. The recently proposed category of "dissociative depression" (Sar, 2011) seems to be a promising concept for future research on psychosomatic aspects of traumatic stress.

  5. Phosphatidylinositol 3-kinase activates ERK in primary sensory neurons and mediates inflammatory heat hyperalgesia through TRPV1 sensitization.

    PubMed

    Zhuang, Zhi-Ye; Xu, Haoxing; Clapham, David E; Ji, Ru-Rong

    2004-09-22

    Although the PI3K (phosphatidylinositol 3-kinase) pathway typically regulates cell growth and survival, increasing evidence indicates the involvement of this pathway in neural plasticity. It is unknown whether the PI3K pathway can mediate pain hypersensitivity. Intradermal injection of capsaicin and NGF produce heat hyperalgesia by activating their respective TRPV1 (transient receptor potential vanilloid receptor-1) and TrkA receptors on nociceptor sensory nerve terminals. We examined the activation of PI3K in primary sensory DRG neurons by these inflammatory agents and the contribution of PI3K activation to inflammatory pain. We further investigated the correlation between the PI3K and the ERK (extracellular signal-regulated protein kinase) pathway. Capsaicin and NGF induce phosphorylation of the PI3K downstream target AKT (protein kinase B), which is blocked by the PI3K inhibitors LY294002 and wortmannin, indicative of the activation of PI3K by both agents. ERK activation by capsaicin and NGF was also blocked by PI3K inhibitors. Similarly, intradermal capsaicin in rats activated PI3K and ERK in C-fiber DRG neurons and epidermal nerve fibers. Injection of PI3K or MEK (ERK kinase) inhibitors into the hindpaw attenuated capsaicin- and NGF-evoked heat hyperalgesia but did not change basal heat sensitivity. Furthermore, PI3K, but not ERK, inhibition blocked early induction of hyperalgesia. In acutely dissociated DRG neurons, the capsaicin-induced TRPV1 current was strikingly potentiated by NGF, and this potentiation was completely blocked by PI3K inhibitors and primarily suppressed by MEK inhibitors. Therefore, PI3K induces heat hyperalgesia, possibly by regulating TRPV1 activity, in an ERK-dependent manner. The PI3K pathway also appears to play a role that is distinct from ERK by regulating the early onset of inflammatory pain.

  6. Acute brain trauma

    PubMed Central

    Martin, GT

    2016-01-01

    In the 20th century, the complications of head injuries were controlled but not eliminated. The wars of the 21st century turned attention to blast, the instant of impact and the primary injury of concussion. Computer calculations have established that in the first 5 milliseconds after the impact, four independent injuries on the brain are inflicted: 1) impact and its shockwave, 2) deceleration, 3) rotation and 4) skull deformity with vibration (or resonance). The recovery, pathology and symptoms after acute brain trauma have always been something of a puzzle. The variability of these four modes of injury, along with a variable reserve of neurones, explains some of this problem. PMID:26688392

  7. Acute brain trauma.

    PubMed

    Martin, G T

    2016-01-01

    In the 20th century, the complications of head injuries were controlled but not eliminated. The wars of the 21st century turned attention to blast, the instant of impact and the primary injury of concussion. Computer calculations have established that in the first 5 milliseconds after the impact, four independent injuries on the brain are inflicted: 1) impact and its shockwave, 2) deceleration, 3) rotation and 4) skull deformity with vibration (or resonance). The recovery, pathology and symptoms after acute brain trauma have always been something of a puzzle. The variability of these four modes of injury, along with a variable reserve of neurones, explains some of this problem.

  8. Dissociative symptoms and dissociative disorders comorbidity in obsessive compulsive disorder: Symptom screening, diagnostic tools and reflections on treatment.

    PubMed

    Belli, Hasan

    2014-08-16

    Borderline personality disorder, conversion disorder and obsessive compulsive disorder frequently have dissociative symptoms. The literature has demonstrated that the level of dissociation might be correlated with the severity of obsessive compulsive disorder (OCD) and that those not responding to treatment had high dissociative symptoms. The structured clinical interview for DSM-IV dissociative disorders, dissociation questionnaire, somatoform dissociation questionnaire and dissociative experiences scale can be used for screening dissociative symptoms and detecting dissociative disorders in patients with OCD. However, a history of neglect and abuse during childhood is linked to a risk factor in the pathogenesis of dissociative psychopathology in adults. The childhood trauma questionnaire-53 and childhood trauma questionnaire-40 can be used for this purpose. Clinicians should not fail to notice the hidden dissociative symptoms and childhood traumatic experiences in OCD cases with severe symptoms that are resistant to treatment. Symptom screening and diagnostic tools used for this purpose should be known. Knowing how to treat these pathologies in patients who are diagnosed with OCD can be crucial.

  9. Dissociative symptoms and dissociative disorders comorbidity in obsessive compulsive disorder: Symptom screening, diagnostic tools and reflections on treatment

    PubMed Central

    Belli, Hasan

    2014-01-01

    Borderline personality disorder, conversion disorder and obsessive compulsive disorder frequently have dissociative symptoms. The literature has demonstrated that the level of dissociation might be correlated with the severity of obsessive compulsive disorder (OCD) and that those not responding to treatment had high dissociative symptoms. The structured clinical interview for DSM-IV dissociative disorders, dissociation questionnaire, somatoform dissociation questionnaire and dissociative experiences scale can be used for screening dissociative symptoms and detecting dissociative disorders in patients with OCD. However, a history of neglect and abuse during childhood is linked to a risk factor in the pathogenesis of dissociative psychopathology in adults. The childhood trauma questionnaire-53 and childhood trauma questionnaire-40 can be used for this purpose. Clinicians should not fail to notice the hidden dissociative symptoms and childhood traumatic experiences in OCD cases with severe symptoms that are resistant to treatment. Symptom screening and diagnostic tools used for this purpose should be known. Knowing how to treat these pathologies in patients who are diagnosed with OCD can be crucial. PMID:25133142

  10. Dissociation and memory fragmentation in post-traumatic stress disorder: an evaluation of the dissociative encoding hypothesis.

    PubMed

    Bedard-Gilligan, Michele; Zoellner, Lori A

    2012-01-01

    Several prominent theories of post-traumatic stress disorder (PTSD) posit that peritraumatic dissociation results in insufficient encoding of the trauma memory and that persistent dissociation prevents memory elaboration, resulting in memory fragmentation and PTSD. In this review we summarise the empirical literature on peritraumatic and trait dissociation and trauma narrative fragmentation as measured by meta-memory and rater/objective coding. Across 16 studies to date, the association between dissociation and fragmentation was most prominent when examining peritraumatic dissociation and patient's own ratings of memory fragmentation. This relationship did not hold when examining trait dissociation or rater-coded or computer-generated measures of fragmentation. Thus initial evidence points more towards a strong self-reported association between constructs that is not supported on more objective fragmentation coding. Measurement overlap, construct ambiguity, and exclusion of potential confounds may underlie lack of a strong association between dissociation and objective-rated fragmentation.

  11. Antagonist pharmacology of desensitizing and non-desensitizing nicotinic acetylcholine receptors in cockroach neurons.

    PubMed

    Salgado, Vincent L

    2016-09-01

    Two α-bungarotoxin-sensitive nicotinic acetylcholine (ACh) receptor subtypes in neurons of the American cockroach have been identified as desensitizing (nAChD) and selectively inhibitable with 100nM imidacloprid, and non-desensitizing (nAChN) and selectively inhibitable with 100pM methyllycaconitine. In this paper, the single-electrode voltage-clamp technique was used to measure concentration-response relations for the action of ACh and five antagonists on pharmacologically separated nAChD and nAChN receptors of acutely dissociated neurons from thoracic ganglia of the American cockroach. A dual bath and U-tube perfusion system was used to achieve rapid application of ACh in the continued presence of antagonists, which was essential to accurately measure inhibition by rapidly-reversible antagonists. ACh activated both receptors with an EC50 of 7μM and the antagonist potencies were (nAChD/nAChN in nM): dihydro-β-erythroidine: 1.0/5.6, d-tubocurarine: 1000/34, condelphine: 0.39/0.65, phencyclidine: 74/980 and mecamylamine 47/1150. While each of these antagonists displayed some subtype selectivity, none are selective enough to be used as subtype-selective tools. These results bring to a total of 16 the number of nicotinic compounds that have been measured on nAChD and nAChN currents. Characterization of these receptors is important for understanding the role of nAChRs in the insect nervous system and the mechanism of action of insecticides.

  12. Bradykinin decreases K+ and increases Cl− conductances in vagal afferent neurones of the guinea pig

    PubMed Central

    Oh, Eun Joo; Weinreich, Daniel

    2004-01-01

    Bradykinin (BK) is an inflammatory mediator that can excite and sensitize primary afferent neurones. The nature of the ionic channels underlying the excitatory actions of BK is still incompletely understood. Using whole-cell patch-clamp recording from acutely dissociated nodose ganglion neurones (NGNs) we have examined the ionic mechanism responsible for BK's excitatory effect. Bath-applied BK (0.1 μm) depolarized the membrane potential (29 ± 3.1 mV, n = 7), evoked action potentials, and induced an inward ionic current (IBK) with two distinctive membrane conductances (gm). Initially, gm decreased; the ionic current associated with this gm had a reversal potential (Erev) value of −87 ± 1.1 mV (n = 26), a value close to EK (−89 mV). Subsequently, gm increased; the ionic current associated with this gm had an estimated Erev of 49 ± 4.3 mV (n = 23). When the second component was isolated from the first component, by replacing [K+]o with Cs+, Erev was 20 ± 4.7 mV (n = 10). Replacing external NaCl with NMDG-Cl or choline-Cl, or reducing [Ca2+]o did not significantly diminish IBK. After replacing external NaCl with sodium isethionate, Erev for the second component shifted to 56 ± 8.8 mV (n = 4), a value close to the ECl (66 mV). The second component was inhibited by intracellular BAPTA or by bath application of niflumic acid (100 μm), a Ca2+-activated Cl− channel blocker. These results suggest that the first and second components of IBK are produced by a decrease in K+ conductance and an increase in Ca2+-activated Cl− conductance, respectively. The BK-evoked Cl− conductance in NGNs may be the first demonstration of an inflammatory mediator exciting primary afferents via an anion channel. PMID:15169850

  13. Neuronal IFN signaling is dispensable for the establishment of HSV-1 latency.

    PubMed

    Rosato, Pamela C; Katzenell, Sarah; Pesola, Jean M; North, Brian; Coen, Donald M; Leib, David A

    2016-10-01

    IFN responses control acute HSV infection, but their role in regulating HSV latency is poorly understood. To address this we used mice lacking IFN signaling specifically in neural tissues. These mice supported a higher acute viral load in nervous tissue and delayed establishment of latency. While latent HSV-1 genome copies were equivalent, ganglia from neuronal IFN signaling-deficient mice unexpectedly supported reduced reactivation. IFNβ promoted survival of primary sensory neurons after infection with HSV-1, indicating a role for IFN signaling in sustaining neurons. We observed higher levels of latency associated transcripts (LATs) per HSV genome in mice lacking neuronal IFN signaling, consistent with a role for IFN in regulating LAT expression. These data show that neuronal IFN signaling modulates the expression of LAT and may conserve the pool of neurons available to harbor latent HSV-1 genome. The data also show that neuronal IFN signaling is dispensable for the establishment of latency.

  14. Mast cells drive mesenteric afferent signalling during acute intestinal ischaemia.

    PubMed

    Jiang, Wen; Kirkup, Anthony J; Grundy, David

    2011-08-01

    Acute intestinal ischaemia stimulates visceral afferent nerves but the mechanisms responsible for this excitation are not fully understood. Mast cells may participate in this process as they are known to signal to mesenteric afferents during intestinal anaphylaxis and contribute to early inflammation and neuronal damage in response to cerebral ischaemia. We therefore hypothesised that mast cells are early responders to acute intestinal ischaemia and their activation initiates rapid signalling to the CNS via the excitation of mesenteric afferents. Primary afferent firing was recorded from a mesenteric nerve bundle supplying a segment of jejunum in anaesthetized adult rats. Acute focal ischaemia was produced by clamping theme senteric vessels for 8 min, and reperfusion followed removal of the vessel clip. Two episodes of ischaemia–reperfusion (I–R) separated by a 30 min interval were performed. Drugs or their vehicles were administered 10 min before the 2nd I–R episode. Ischaemia caused a reproducible, intense and biphasic afferent firing that was temporally dissociated from the concomitantly triggered complex pattern of intestinal motor activity. The L-type calcium channel blocker, nifedipine, significantly attenuated this afferent firing by a mechanism independent of its action on intestinal tone. Ischaemia-induced afferent firing was also abrogated by the mast cell stabilizer, doxantrazole, and the H1 histamine receptor antagonist, pyrilamine. In contrast, the nicotinic receptor antagonist, hexamethonium, and the N-type calcium channel toxin, ω-conotoxin GVIA, each reduced the ischaemia-evoked motor inhibition but not the concurrent afferent discharge. Similarly, the cyclooxygenase inhibitor, naproxen, had no effect on the ischaemic afferent response but reduced the intestinal tone shortly from the onset of ischaemia to the early period of reperfusion. These data support a critical role for mast cell-derived histamine in the direct chemoexcitation of

  15. Differentiation of oligodendrocyte progenitor cells from dissociated monolayer and feeder-free cultured pluripotent stem cells

    PubMed Central

    Miyamoto, Yuki; Bando, Yoshio; Ono, Takashi; Kobayashi, Sakurako; Doi, Ayano; Araki, Toshihiro; Kato, Yosuke; Shirakawa, Takayuki; Suzuki, Yutaka; Yamauchi, Junji; Yoshida, Shigetaka; Sato, Naoya

    2017-01-01

    Oligodendrocytes myelinate axons and form myelin sheaths in the central nervous system. The development of therapies for demyelinating diseases, including multiple sclerosis and leukodystrophies, is a challenge because the pathogenic mechanisms of disease remain poorly understood. Primate pluripotent stem cell-derived oligodendrocytes are expected to help elucidate the molecular pathogenesis of these diseases. Oligodendrocytes have been successfully differentiated from human pluripotent stem cells. However, it is challenging to prepare large amounts of oligodendrocytes over a short amount of time because of manipulation difficulties under conventional primate pluripotent stem cell culture methods. We developed a proprietary dissociated monolayer and feeder-free culture system to handle pluripotent stem cell cultures. Because the dissociated monolayer and feeder-free culture system improves the quality and growth of primate pluripotent stem cells, these cells could potentially be differentiated into any desired functional cells and consistently cultured in large-scale conditions. In the current study, oligodendrocyte progenitor cells and mature oligodendrocytes were generated within three months from monkey embryonic stem cells. The embryonic stem cell-derived oligodendrocytes exhibited in vitro myelinogenic potency with rat dorsal root ganglion neurons. Additionally, the transplanted oligodendrocyte progenitor cells differentiated into myelin basic protein-positive mature oligodendrocytes in the mouse corpus callosum. This preparative method was used for human induced pluripotent stem cells, which were also successfully differentiated into oligodendrocyte progenitor cells and mature oligodendrocytes that were capable of myelinating rat dorsal root ganglion neurons. Moreover, it was possible to freeze, thaw, and successfully re-culture the differentiating cells. These results showed that embryonic stem cells and human induced pluripotent stem cells maintained in a

  16. Differentiation of oligodendrocyte progenitor cells from dissociated monolayer and feeder-free cultured pluripotent stem cells.

    PubMed

    Yamashita, Tomoko; Miyamoto, Yuki; Bando, Yoshio; Ono, Takashi; Kobayashi, Sakurako; Doi, Ayano; Araki, Toshihiro; Kato, Yosuke; Shirakawa, Takayuki; Suzuki, Yutaka; Yamauchi, Junji; Yoshida, Shigetaka; Sato, Naoya

    2017-01-01

    Oligodendrocytes myelinate axons and form myelin sheaths in the central nervous system. The development of therapies for demyelinating diseases, including multiple sclerosis and leukodystrophies, is a challenge because the pathogenic mechanisms of disease remain poorly understood. Primate pluripotent stem cell-derived oligodendrocytes are expected to help elucidate the molecular pathogenesis of these diseases. Oligodendrocytes have been successfully differentiated from human pluripotent stem cells. However, it is challenging to prepare large amounts of oligodendrocytes over a short amount of time because of manipulation difficulties under conventional primate pluripotent stem cell culture methods. We developed a proprietary dissociated monolayer and feeder-free culture system to handle pluripotent stem cell cultures. Because the dissociated monolayer and feeder-free culture system improves the quality and growth of primate pluripotent stem cells, these cells could potentially be differentiated into any desired functional cells and consistently cultured in large-scale conditions. In the current study, oligodendrocyte progenitor cells and mature oligodendrocytes were generated within three months from monkey embryonic stem cells. The embryonic stem cell-derived oligodendrocytes exhibited in vitro myelinogenic potency with rat dorsal root ganglion neurons. Additionally, the transplanted oligodendrocyte progenitor cells differentiated into myelin basic protein-positive mature oligodendrocytes in the mouse corpus callosum. This preparative method was used for human induced pluripotent stem cells, which were also successfully differentiated into oligodendrocyte progenitor cells and mature oligodendrocytes that were capable of myelinating rat dorsal root ganglion neurons. Moreover, it was possible to freeze, thaw, and successfully re-culture the differentiating cells. These results showed that embryonic stem cells and human induced pluripotent stem cells maintained in a

  17. Neuronal Migration Disorders

    MedlinePlus

    ... Understanding Sleep The Life and Death of a Neuron Order Publications Support Resources Patient Organizations Professional Societies ... birth defects caused by the abnormal migration of neurons in the developing brain and nervous system. In ...

  18. On the Dynamics of the Spontaneous Activity in Neuronal Networks

    PubMed Central

    Bonifazi, Paolo; Ruaro, Maria Elisabetta; Torre, Vincent

    2007-01-01

    Most neuronal networks, even in the absence of external stimuli, produce spontaneous bursts of spikes separated by periods of reduced activity. The origin and functional role of these neuronal events are still unclear. The present work shows that the spontaneous activity of two very different networks, intact leech ganglia and dissociated cultures of rat hippocampal neurons, share several features. Indeed, in both networks: i) the inter-spike intervals distribution of the spontaneous firing of single neurons is either regular or periodic or bursting, with the fraction of bursting neurons depending on the network activity; ii) bursts of spontaneous spikes have the same broad distributions of size and duration; iii) the degree of correlated activity increases with the bin width, and the power spectrum of the network firing rate has a 1/f behavior at low frequencies, indicating the existence of long-range temporal correlations; iv) the activity of excitatory synaptic pathways mediated by NMDA receptors is necessary for the onset of the long-range correlations and for the presence of large bursts; v) blockage of inhibitory synaptic pathways mediated by GABAA receptors causes instead an increase in the correlation among neurons and leads to a burst distribution composed only of very small and very large bursts. These results suggest that the spontaneous electrical activity in neuronal networks with different architectures and functions can have very similar properties and common dynamics. PMID:17502919

  19. The role of dimensionality in neuronal network dynamics

    PubMed Central

    Ulloa Severino, Francesco Paolo; Ban, Jelena; Song, Qin; Tang, Mingliang; Bianconi, Ginestra; Cheng, Guosheng; Torre, Vincent

    2016-01-01

    Recent results from network theory show that complexity affects several dynamical properties of networks that favor synchronization. Here we show that synchronization in 2D and 3D neuronal networks is significantly different. Using dissociated hippocampal neurons we compared properties of cultures grown on a flat 2D substrates with those formed on 3D graphene foam scaffolds. Both 2D and 3D cultures had comparable glia to neuron ratio and the percentage of GABAergic inhibitory neurons. 3D cultures because of their dimension have many connections among distant neurons leading to small-world networks and their characteristic dynamics. After one week, calcium imaging revealed moderately synchronous activity in 2D networks, but the degree of synchrony of 3D networks was higher and had two regimes: a highly synchronized (HS) and a moderately synchronized (MS) regime. The HS regime was never observed in 2D networks. During the MS regime, neuronal assemblies in synchrony changed with time as observed in mammalian brains. After two weeks, the degree of synchrony in 3D networks decreased, as observed in vivo. These results show that dimensionality determines properties of neuronal networks and that several features of brain dynamics are a consequence of its 3D topology. PMID:27404281

  20. Considering psychoeducation on structural dissociation for dialectical behavior therapy patients experiencing high-risk dissociative behaviors.

    PubMed

    Shabb, Olivia

    2016-01-01

    Dialectical behavioral therapy (DBT) programs, particularly for low-functioning individuals at the safety and stabilization phase of therapy, work with a variety of high-risk and often complex cases, with a curriculum consisting primarily of concrete skill acquisition and application. A significant subset of individuals in DBT programs, however, may suffer high-risk dissociative episodes in which skill application may be less available to them, contributing to further destabilization, demoralization, and thoughts of self-inefficacy in treatment. This article evaluates the potential benefits of complementing traditional DBT with psychoeducation on structural dissociation for such patients, acknowledging and addressing some of the concerns that might accompany such a consideration.

  1. Dissociation, PTSD, and Substance Abuse: An Empirical Study

    PubMed Central

    Najavits, Lisa; Walsh, Marybeth

    2012-01-01

    Few studies have examined the relationship between posttraumatic stress disorder (PTSD), substance use disorder (SUD) and dissociation. We studied 77 women with current PTSD and substance dependence, classified into high- versus low-dissociation on the Dissociative Experiences Scale. They were compared on trauma- and substance-related symptoms, cognitions, coping skills, social adjustment, trauma history, psychiatric symptoms, and self-harm/suicidal behaviors. We found the high-dissociation group consistently more impaired than the low-dissociation group. Also, the sample overall evidenced relatively high levels of dissociation, indicating that even in the presence of recent substance use, dissociation remains a major psychological phenomenon. Indeed, the high-dissociation group reported stronger expectation that substances could manage their psychiatric symptoms. The high-dissociation group also had more trauma-related symptoms and childhood histories of emotional abuse and physical neglect. Discussion addresses methodology, the “chemical dissociation” hypothesis, and the need for more nuanced understanding of how substances are experienced in relation to dissociative phenomena. PMID:22211445

  2. The role of water in gas hydrate dissociation

    USGS Publications Warehouse

    Circone, S.; Stern, L.A.; Kirby, S.H.

    2004-01-01

    When raised to temperatures above the ice melting point, gas hydrates release their gas in well-defined, reproducible events that occur within self-maintained temperature ranges slightly below the ice point. This behavior is observed for structure I (carbon dioxide, methane) and structure II gas hydrates (methane-ethane, and propane), including those formed with either H2O- or D2O-host frameworks, and dissociated at either ambient or elevated pressure conditions. We hypothesize that at temperatures above the H2O (or D2O) melting point: (1) hydrate dissociation produces water + gas instead of ice + gas, (2) the endothermic dissociation reaction lowers the temperature of the sample, causing the water product to freeze, (3) this phase transition buffers the sample temperatures within a narrow temperature range just below the ice point until dissociation goes to completion, and (4) the temperature depression below the pure ice melting point correlates with the average rate of dissociation and arises from solution of the hydrate-forming gas, released by dissociation, in the water phase at elevated concentrations. In addition, for hydrate that is partially dissociated to ice + gas at lower temperatures and then heated to temperatures above the ice point, all remaining hydrate dissociates to gas + liquid water as existing barriers to dissociation disappear. The enhanced dissociation rates at warmer temperatures are probably associated with faster gas transport pathways arising from the formation of water product.

  3. Traumatic Memories in Acute Stress Disorder: An Analysis of Narratives before and after Treatment

    ERIC Educational Resources Information Center

    Moulds, Michelle L.; Bryant, Richard A.

    2005-01-01

    The dissociative reactions in acute stress disorder purportedly impede encoding and organization of traumatic memories and consequently impair the individual's ability to retrieve trauma-related details. A qualitative examination was conducted on trauma narratives of individuals with acute stress disorder (N = 15) prior to cognitive behavior…

  4. Neurofibromin and Neuronal Apoptosis

    DTIC Science & Technology

    2005-07-01

    for these differences in the response of Nfl-/- neurons. "So What" Section. The learning disabilities associated with NF I constitute a highly variable...and +/+ neurons appear to become more significant with age. Our results may have implications for two areas: 1) the pathogenesis of learning ... disabilities in children with NF I, and 2) therapeutic strategies or targets for prolonging neuron survival, or for increasing neuronal response to protective

  5. Immunohistological demonstration of CaV3.2 T-type voltage-gated calcium channel expression in soma of dorsal root ganglion neurons and peripheral axons of rat and mouse

    PubMed Central

    Rose, Kirstin E.; Lunardi, Nadia; Boscolo, Annalisa; Dong, Xinzhong; Erisir, Alev; Jevtovic-Todorovic, Vesna; Todorovic, Slobodan M.

    2013-01-01

    Previous behavioural studies have revealed that CaV3.2 T-type calcium channels support peripheral nociceptive transmission and electrophysiological studies have established the presence of T-currents in putative nociceptive sensory neurons of dorsal root ganglion (DRG). To date, however, the localization pattern of this key nociceptive channel in the soma and peripheral axons of these cells has not been demonstrated due to lack of isoform-selective anti-CaV3.2 antibodies. In the present study a new polyclonal CaV3.2 antibody is used to localize CaV3.2 expression in rodent DRG neurons using different staining techniques including confocal and electron microscopy. Confocal microscopy of both acutely dissociated cells and short-term cultures demonstrated strong immunofluorescence of anti-CaV3.2 antibody that was largely confined to smaller diameter DRG neurons where it co-localized with established immuno-markers of unmyelinated nociceptors, such as, CGRP, IB4 and peripherin. In contrast, a smaller proportion of these CaV3.2-labeled DRG cells also co-expressed NF-200, a marker of myelinated sensory neurons. In the rat sciatic nerve preparation, confocal microscopy demonstrated anti-CaV3.2 immunofluorescence which was co-localized with both peripherin and NF-200. Further, electron microscopy revealed immuno-gold labelling of CaV3.2 preferentially in association with un-myelinated sensory fibres from mouse sciatic nerve. Finally, we demonstrated the expression of CaV3.2 channels in peripheral nerve endings of mouse hindpaw skin as shown by co-localisation with Mrgpd-GFP-positive fibres. The CaV3.2 expression within the soma and peripheral axons of nociceptive sensory neurons further demonstrates the importance of this channel in peripheral pain transmission. PMID:23867767

  6. Small object detection neurons in female hoverflies.

    PubMed

    Nordström, Karin; O'Carroll, David C

    2006-05-22

    While predators such as dragonflies are dependent on visual detection of moving prey, social interactions make conspecific detection equally important for many non-predatory insects. Specialized 'acute zones' associated with target detection have evolved in several insect groups and are a prominent male-specific feature in many dipteran flies. The physiology of target selective neurons associated with these specialized eye regions has previously been described only from male flies. We show here that female hoverflies (Eristalis tenax) have several classes of neurons within the third optic ganglion (lobula) capable of detecting moving objects smaller than 1 degrees . These neurons have frontal receptive fields covering a large part of the ipsilateral world and are tuned to a broad range of target speeds and sizes. This could make them suitable for detecting targets under a range of natural conditions such as required during predator avoidance or conspecific interactions.

  7. In utero Electroporation followed by Primary Neuronal Culture for Studying Gene Function in Subset of Cortical Neurons

    PubMed Central

    Rice, Heather; Suth, Seiyam; Cavanaugh, William; Bai, Jilin; Young-Pearse, Tracy L.

    2010-01-01

    In vitro study of primary neuronal cultures allows for quantitative analyses of neurite outgrowth. In order to study how genetic alterations affect neuronal process outgrowth, shRNA or cDNA constructs can be introduced into primary neurons via chemical transfection or viral transduction. However, with primary cortical cells, a heterogeneous pool of cell types (glutamatergic neurons from different layers, inhibitory neurons, glial cells) are transfected using these methods. The use of in utero electroporation to introduce DNA constructs in the embryonic rodent cortex allows for certain subsets of cells to be targeted: while electroporation of early embryonic cortex targets deep layers of the cortex, electroporation at late embryonic timepoints targets more superficial layers. Further, differential placement of electrodes across the heads of individual embryos results in the targeting of dorsal-medial versus ventral-lateral regions of the cortex. Following electroporation, transfected cells can be dissected out, dissociated, and plated in vitro for quantitative analysis of neurite outgrowth. Here, we provide a step-by-step method to quantitatively measure neuronal process outgrowth in subsets of cortical cells. The basic protocol for in utero electroporation has been described in detail in two other JoVE articles from the Kriegstein lab 1, 2. We will provide an overview of our protocol for in utero electroporation, focusing on the most important details, followed by a description of our protocol that applies in utero electroporation to the study of gene function in neuronal process outgrowth. PMID:20972409

  8. Excitatory cortical neurons with multipolar shape establish neuronal polarity by forming a tangentially oriented axon in the intermediate zone.

    PubMed

    Hatanaka, Yumiko; Yamauchi, Kenta

    2013-01-01

    The formation of axon-dendrite polarity is crucial for neuron to make the proper information flow within the brain. Although the processes of neuronal polarity formation have been extensively studied using neurons in dissociated culture, the corresponding developmental processes in vivo are still unclear. Here, we illuminate the initial steps of morphological polarization of excitatory cortical neurons in situ, by sparsely labeling their neuroepithelial progenitors using in utero electroporation and then examining their neuronal progeny in brain sections and in slice cultures. Morphological analysis showed that an axon-like long tangential process formed in progeny cells in the intermediate zone (IZ). Time-lapse imaging analysis using slice culture revealed that progeny cells with multipolar shape, after alternately extending and retracting their short processes for several hours, suddenly elongated a long process tangentially. These cells then transformed into a bipolar shape, extending a pia-directed leading process, and migrated radially leaving the tangential process behind, which gave rise to an "L-shaped" axon. Our findings suggest that neuronal polarity in these cells is established de novo from a nonpolarized stage in vivo and indicate that excitatory cortical neurons with multipolar shape in the IZ initiate axon outgrowth before radial migration into the cortical plate.

  9. [Faith vs. science: soul's possession or dissociative disorder? A case study].

    PubMed

    Barabasz, Aleksandra; Hyrnik, Joanna; Janas-Kozik, Małgorzata; Jelonek, Ireneusz

    2012-01-01

    The aim of this paper is to discuss the impact and significance of religious beliefs on the dissociation and somatization symptoms presented by a hospitalised female patient. A 16-year-old girl was hospitalised at the Developmental Age Psychiatry and Psychotherapy Clinical Ward (The Clinical PiPWR Ward) for observation; she had been referred from the Regional Acute Poisoning Centre where she had been admitted upon taking some medications. For two years she had been subjected to exorcisms due to "possession by the Evil". Religious convictions had been sustained and enhanced by the patient's parents as well as a local Catholic community. The observation and diagnosis at the PiPWR Clinical Ward revealed mixed dissociation and somatization disorders as well as an abnormally shaping personality. The presented case, on the basis of the clinical observation and the analysis of literature on the subject, led to the following conclusions: the emotional issues and the system of religious beliefs influenced the shape of symptomatology, enforced the functioning of immature defensive mechanisms and intensified the dissociation and somatization disorders in the patient. The diagnosed mental disorders require that the girl should undergo individual and family psychotherapy.

  10. Ritual homicide during dissociative trance disorder.

    PubMed

    Ferracuti, Stefano; DeMarco, Maria Civita

    2004-02-01

    A case report is described of a man who developed a single period of recurrent episodes of dissociative trance disorder (DTD) during a family stress. The cultural environment was permeated by thoughts and beliefs in magic. During one trance state, the man performed an exorcism on the 6-month-old baby of his brother-in-law, and the baby died from cerebral hemorrhage. In the 5-year follow-up, no other episodes of DTD developed, and the man is serving an 18-year sentence.

  11. Dissociative Ionization of Aromatic and Heterocyclic Molecules

    NASA Technical Reports Server (NTRS)

    Huo, Winifred M.

    2003-01-01

    Space radiation poses a major health hazard to humans in space flight. The high-energy charged particles in space radiation ranging from protons to high atomic number, high-energy (HZE) particles, and the secondary species they produce, attack DNA, cells, and tissues. Of the potential hazards, long-term health effects such as carcinogenesis are likely linked to the DNA lesions caused by secondary electrons in the 1 - 30 eV range. Dissociative ionization (DI) is one of the electron collision processes that can damage the DNA, either directly by causing a DNA lesion, or indirectly by producing radicals and cations that attack the DNA. To understand this process, we have developed a theoretical model for DI. Our model makes use of the fact that electron motion is much faster than nuclear motion and assumes DI proceeds through a two-step process. The first step is electron-impact ionization resulting in a particular state of the molecular ion in the geometry of the neutral molecule. In the second step the ion undergoes unimolecular dissociation. Thus the DI cross section sigma(sup DI)(sub a) for channel a is given by sigma(sup DI)(sub a) = sigma(sup I)(sub a) P(sub D) with sigma(sup I)(sub a) the ionization cross section of channel a and P(sub D) the dissociation probability. This model has been applied to study the DI of H2O, NH3, and CH4, with results in good agreement with experiment. The ionization cross section sigma(sup I)(sub a) was calculated using the improved binary encounter-dipole model and the unimolecular dissociation probability P(sub D) obtained by following the minimum energy path determined by the gradients and Hessians of the electronic energy with respect to the nuclear coordinates of the ion. This model is used to study the DI from the low-lying channels of benzene and pyridine to understand the different product formation in aromatic and heterocyclic molecules. DI study of the DNA base thymine is underway. Solvent effects will also be discussed.

  12. Spin–orbit interaction mediated molecular dissociation

    SciTech Connect

    Kokkonen, E. Jänkälä, K.; Kettunen, J. A.; Heinäsmäki, S.; Karpenko, A.; Huttula, M.; Löytynoja, T.

    2014-05-14

    The effect of the spin–orbit interaction to photofragmentation is investigated in the mercury(II) bromide (HgBr{sub 2}) molecule. Changes in the fragmentation between the two spin–orbit components of Hg 5d photoionization, as well as within the molecular-field-splitted levels of these components are observed. Dissociation subsequent to photoionization is studied with synchrotron radiation and photoelectron-photoion coincidence spectroscopy. The experimental results are accompanied by relativistic ab initio analysis of the photoelectron spectrum.

  13. On the dissociation energy of Mg2

    NASA Astrophysics Data System (ADS)

    Partridge, Harry; Bauschlicher, Charles W., Jr.; Pettersson, Lars G. M.; McLean, A. D.; Liu, Bowen

    1990-05-01

    The bonding in the X 1Sigma(+)g state of Mg2 is investigated using near-complete valence one-particle Slater and Gaussian basis sets containing up to h functions. It is shown that the four-electron complete CI limit can be approached using a sequence of either second-order CI (SOCI) or interacting correlated fragment (ICF) calculations. At the valence level, the best estimate of the dissociation energy D(e) was 464/cm. This is a lower limit and is probably within 5/cm of the complete basis value.

  14. Acetaminophen Induces Apoptosis in Rat Cortical Neurons

    PubMed Central

    Posadas, Inmaculada; Santos, Pablo; Blanco, Almudena; Muñoz-Fernández, Maríangeles; Ceña, Valentín

    2010-01-01

    Background Acetaminophen (AAP) is widely prescribed for treatment of mild pain and fever in western countries. It is generally considered a safe drug and the most frequently reported adverse effect associated with acetaminophen is hepatotoxicity, which generally occurs after acute overdose. During AAP overdose, encephalopathy might develop and contribute to morbidity and mortality. Our hypothesis is that AAP causes direct neuronal toxicity contributing to the general AAP toxicity syndrome. Methodology/Principal Findings We report that AAP causes direct toxicity on rat cortical neurons both in vitro and in vivo as measured by LDH release. We have found that AAP causes concentration-dependent neuronal death in vitro at concentrations (1 and 2 mM) that are reached in human plasma during AAP overdose, and that are also reached in the cerebrospinal fluid of rats for 3 hours following i.p injection of AAP doses (250 and 500 mg/Kg) that are below those required to induce acute hepatic failure in rats. AAP also increases both neuronal cytochrome P450 isoform CYP2E1 enzymatic activity and protein levels as determined by Western blot, leading to neuronal death through mitochondrial–mediated mechanisms that involve cytochrome c release and caspase 3 activation. In addition, in vivo experiments show that i.p. AAP (250 and 500 mg/Kg) injection induces neuronal death in the rat cortex as measured by TUNEL, validating the in vitro data. Conclusions/Significance The data presented here establish, for the first time, a direct neurotoxic action by AAP both in vivo and in vitro in rats at doses below those required to produce hepatotoxicity and suggest that this neurotoxicity might be involved in the general toxic syndrome observed during patient APP overdose and, possibly, also when AAP doses in the upper dosing schedule are used, especially if other risk factors (moderate drinking, fasting, nutritional impairment) are present. PMID:21170329

  15. Electron transfer dissociation of modified peptides and proteins.

    PubMed

    Zhou, Yuping; Dong, Jia; Vachet, Richard W

    2011-10-01

    Mass spectrometry is the method of choice for sequencing peptides and proteins and is the preferred choice for characterizing post-translational modifications (PTMs). The most commonly used dissociation method to characterize peptides (i.e. collision-induced dissociation (CID)), however, has some limitations when it comes to analyzing many PTMs. Because CID chemistry is influenced by amino acid side-chains, some modifications can alter or inhibit dissociation along the peptide backbone, thereby limiting sequence information and hindering identification of the modification site. Electron transfer dissociation (ETD) has emerged as an alternate dissociation technique that, in most cases, overcomes these limitations of CID because it is less affected by side chain chemistry. Here, we review recent applications of ETD for characterizing peptide and protein PTMs with a particular emphasis on the advantages of ETD over CID, the ways in which ETD and CID have been used in a complementary manner, and how peptide modifications can still influence ETD dissociation pathways.

  16. Strain-induced water dissociation on supported ultrathin oxide films

    PubMed Central

    Song, Zhenjun; Fan, Jing; Xu, Hu

    2016-01-01

    Controlling the dissociation of single water molecule on an insulating surface plays a crucial role in many catalytic reactions. In this work, we have identified the enhanced chemical reactivity of ultrathin MgO(100) films deposited on Mo(100) substrate that causes water dissociation. We reveal that the ability to split water on insulating surface closely depends on the lattice mismatch between ultrathin films and the underlying substrate, and substrate-induced in-plane tensile strain dramatically results in water dissociation on MgO(100). Three dissociative adsorption configurations of water with lower energy are predicted, and the structural transition going from molecular form to dissociative form is almost barrierless. Our results provide an effective avenue to achieve water dissociation at the single-molecule level and shed light on how to tune the chemical reactions of insulating surfaces by choosing the suitable substrates. PMID:26953105

  17. Dissociation and fantasy proneness in psychiatric patients: a preliminary study.

    PubMed

    Merckelbach, Harald; à Campo, Joost; Hardy, Solange; Giesbrecht, Timo

    2005-01-01

    Nonclinical studies found that dissociative experiences are intimately linked to a trait known as fantasy proneness. We examined the links among dissociative symptoms, fantasy proneness, and impulsivity in psychiatric outpatients. Our sample consisted of 22 patients with schizophrenia, 20 patients with a diagnosis of borderline personality disorder, and 19 patients with a major depressive disorder. For the whole sample, levels of dissociation were found to be related to fantasy proneness and impulsivity. There were group differences in dissociative symptoms, with patients with borderline personality disorder reporting more such symptoms than patients with either schizophrenia or major depressive disorder. The overlap between dissociation and fantasy proneness may have important ramifications for studies addressing comorbid phenomena of dissociative symptoms.

  18. Dissociation and hallucinations in dyads engaged through interpersonal gazing.

    PubMed

    Caputo, Giovanni B

    2015-08-30

    Interpersonal gazing in dyads, when the two individuals in the dyad stare at each other in the eyes, is investigated in 20 healthy young individuals at low illumination for 10-min. Results indicate dissociative symptoms, dysmorphic face perceptions, and hallucination-like strange-face apparitions. Dissociative symptoms and face dysmorphia were correlated. Strange-face apparitions were non-correlated with dissociation and dysmorphia. These results indicate that dissociative symptoms and hallucinatory phenomena during interpersonal-gazing under low illumination can involve different processes. Strange-face apparitions may characterize the rebound to "reality" (perceptual reality caused by external stimulus and hallucinatory reality caused by internal input) from a dissociative state induced by sensory deprivation. These phenomena may explain psychodynamic projections of the subject's unconscious meanings into the other's face. The results indicate that interpersonal gazing in dyads can be an effective tool for studying experimentally-induced dissociative symptoms and hallucinatory-like apparitions.

  19. Dissociative Experience and Cultural Neuroscience: Narrative, Metaphor and Mechanism

    PubMed Central

    Kirmayer, Laurence J.

    2016-01-01

    Approaches to trance and possession in anthropology have tended to use outmoded models drawn from psychodynamic theory or treated such dissociative phenomena as purely discursive processes of attributing action and experience to agencies other than the self. Within psychology and psychiatry, understanding of dissociative disorders has been hindered by polemical “either/or” arguments: either dissociative disorders are real, spontaneous alterations in brain states that reflect basic neurobiological phenomena, or they are imaginary, socially constructed role performances dictated by interpersonal expectations, power dynamics and cultural scripts. In this paper, we outline an approach to dissociative phenomena, including trance, possession and spiritual and healing practices, that integrates the neuropsychological notions of underlying mechanism with sociocultural processes of the narrative construction and social presentation of the self. This integrative model, grounded in a cultural neuroscience, can advance ethnographic studies of dissociation and inform clinical approaches to dissociation through careful consideration of the impact of social context. PMID:18213511

  20. Peritraumatic dissociative experiences, trauma narratives, and trauma pathology.

    PubMed

    Zoellner, Lori A; Alvarez-Conrad, Jennifer; Foa, Edna B

    2002-02-01

    Peritraumatic dissociation, i.e., dissociation during or immediately after a traumatic event, has been associated with persistence of trauma-related pathology. Peritraumatic dissociation may interfere with encoding of traumatic memories and this style may impede recovery. This study examines this hypothesis by analyzing trauma narratives from 28 female sexual and nonsexual assault victims who reported either high or low peritraumatic dissociation. Participants were asked to recount their assault. Narratives were videotaped, transcribed, and coded. Narratives of individuals with high peritraumatic dissociation had higher grade levels and a trend toward lower reading ease than those with low peritraumatic dissociation. Both higher grade levels and lower reading ease of prethreat sections of trauma narratives were related to posttreatment reexperiencing and anxiety symptoms.

  1. Dissociation energy of the ground state of NaH

    NASA Astrophysics Data System (ADS)

    Huang, Hsien-Yu; Lu, Tsai-Lien; Whang, Thou-Jen; Chang, Yung-Yung; Tsai, Chin-Chun

    2010-07-01

    The dissociation energy of the ground state of NaH was determined by analyzing the observed near dissociation rovibrational levels. These levels were reached by stimulated emission pumping and fluorescence depletion spectroscopy. A total of 114 rovibrational levels in the ranges 9≤v″≤21 and 1≤J″≤14 were assigned to the X Σ1+ state of NaH. The highest vibrational level observed was only about 40 cm-1 from the dissociation limit in the ground state. One quasibound state, above the dissociation limit and confined by the centrifugal barrier, was observed. Determining the vibrational quantum number at dissociation vD from the highest four vibrational levels yielded the dissociation energy De=15 815±5 cm-1. Based on new observations and available data, a set of Dunham coefficients and the rotationless Rydberg-Klein-Rees curve were constructed. The effective potential curve and the quasibound states were discussed.

  2. Electron transfer dissociation versus collisionally activated dissociation of cationized biodegradable polyesters.

    PubMed

    Scionti, Vincenzo; Wesdemiotis, Chrys

    2012-11-01

    Biodegradable polyesters were ionized by electrospray ionization and characterized by tandem mass spectrometry using collisionally activated dissociation (CAD) and electron transfer dissociation (ETD) as activation methods. The compounds studied include one homopolymer, polylactide and two copolymers, poly(ethylene adipate) and poly(butylene adipate). CAD of [M+2Na](2+) ions from these polyesters proceeds via charge-remote 1,5-H rearrangements over the ester groups, leading to cleavages at the (CO)O-alkyl bonds. ETD of the same precursor ions creates a radical anion at the site of electron attachment, which fragments by radical-induced cleavage of the (CO)O-alkyl bonds and by intramolecular nucleophilic substitution at the (CO)-O bonds. In contrast to CAD, ETD produces fragments in one charge state only and does not cause consecutive fragmentations, which simplifies spectral interpretation and permits conclusive identification of the correct end groups. The radical-site reactions occurring during ETD are very similar with those reported for ETD of protonated peptides. Unlike multiply protonated species, multiply sodiated precursors form ion pairs (salt bridges) after electron transfer, thereby promoting dissociations via nucleophilic displacement in addition to the radical-site dissociations typical in ETD.

  3. A Neuron-Based Screening Platform for Optimizing Genetically-Encoded Calcium Indicators

    PubMed Central

    Schreiter, Eric R.; Hasseman, Jeremy P.; Tsegaye, Getahun; Fosque, Benjamin F.; Behnam, Reza; Shields, Brenda C.; Ramirez, Melissa; Kimmel, Bruce E.; Kerr, Rex A.; Jayaraman, Vivek; Looger, Loren L.; Svoboda, Karel; Kim, Douglas S.

    2013-01-01

    Fluorescent protein-based sensors for detecting neuronal activity have been developed largely based on non-neuronal screening systems. However, the dynamics of neuronal state variables (e.g., voltage, calcium, etc.) are typically very rapid compared to those of non-excitable cells. We developed an electrical stimulation and fluorescence imaging platform based on dissociated rat primary neuronal cultures. We describe its use in testing genetically-encoded calcium indicators (GECIs). Efficient neuronal GECI expression was achieved using lentiviruses containing a neuronal-selective gene promoter. Action potentials (APs) and thus neuronal calcium levels were quantitatively controlled by electrical field stimulation, and fluorescence images were recorded. Images were segmented to extract fluorescence signals corresponding to individual GECI-expressing neurons, which improved sensitivity over full-field measurements. We demonstrate the superiority of screening GECIs in neurons compared with solution measurements. Neuronal screening was useful for efficient identification of variants with both improved response kinetics and high signal amplitudes. This platform can be used to screen many types of sensors with cellular resolution under realistic conditions where neuronal state variables are in relevant ranges with respect to timing and amplitude. PMID:24155972

  4. A neuron-based screening platform for optimizing genetically-encoded calcium indicators.

    PubMed

    Wardill, Trevor J; Chen, Tsai-Wen; Schreiter, Eric R; Hasseman, Jeremy P; Tsegaye, Getahun; Fosque, Benjamin F; Behnam, Reza; Shields, Brenda C; Ramirez, Melissa; Kimmel, Bruce E; Kerr, Rex A; Jayaraman, Vivek; Looger, Loren L; Svoboda, Karel; Kim, Douglas S

    2013-01-01

    Fluorescent protein-based sensors for detecting neuronal activity have been developed largely based on non-neuronal screening systems. However, the dynamics of neuronal state variables (e.g., voltage, calcium, etc.) are typically very rapid compared to those of non-excitable cells. We developed an electrical stimulation and fluorescence imaging platform based on dissociated rat primary neuronal cultures. We describe its use in testing genetically-encoded calcium indicators (GECIs). Efficient neuronal GECI expression was achieved using lentiviruses containing a neuronal-selective gene promoter. Action potentials (APs) and thus neuronal calcium levels were quantitatively controlled by electrical field stimulation, and fluorescence images were recorded. Images were segmented to extract fluorescence signals corresponding to individual GECI-expressing neurons, which improved sensitivity over full-field measurements. We demonstrate the superiority of screening GECIs in neurons compared with solution measurements. Neuronal screening was useful for efficient identification of variants with both improved response kinetics and high signal amplitudes. This platform can be used to screen many types of sensors with cellular resolution under realistic conditions where neuronal state variables are in relevant ranges with respect to timing and amplitude.

  5. Imaging the molecular dynamics of dissociative electron attachment to water

    SciTech Connect

    Adaniya, Hidihito; Rudek, B.; Osipov, Timur; Haxton, Dan; Weber, Thorsten; Rescigno, Thomas N.; McCurdy, C.W.; Belkacem, Ali

    2009-10-19

    Momentum imaging experiments on dissociative electron attachment to the water molecule are combined with ab initio theoretical calculations of the angular dependence of the quantum mechanical amplitude for electron attachment to provide a detailed picture of the molecular dynamics of dissociation attachment via the two lowest energy Feshbach resonances. The combination of momentum imaging experiments and theory can reveal dissociation dynamics for which the axial recoil approximation breaks down and thus provides a powerful reaction microscope for DEA to polyatomics.

  6. Anterior opercular cortex lesions cause dissociated lower cranial nerve palsies and anarthria but no aphasia: Foix-Chavany-Marie syndrome and "automatic voluntary dissociation" revisited.

    PubMed

    Weller, M

    1993-01-01

    Anarthria and bilateral central facio-linguovelo-pharyngeo-masticatory paralysis with "automatic voluntary dissociation" are the clinical hallmarks of Foix-Chavany-Marie syndrome (FCMS), the corticosubcortial type of suprabulbar palsy. A literature review of 62 FCMS reports allowed the differentiation of five clinical types of FCMS: (a) the classical and most common form associated with cerebrovascular disease, (b) a subacute form caused by central nervous system infections, (c) a developmental form probably most often related to neuronal migration disorders, (d) a reversible form in children with epilepsy, and (e) a rare type associated with neurodegenerative disorders. Bilateral opercular lesions were confirmed in 31 of 41 patients who had CT or MRI performed, and by necropsy in 7 of 10 patients. FCMS could be attributed to unilateral lesions in 2 patients. The typical presentation and differential diagnosis of FCMS provide important clues to lesion localization in clinical neurology. FCMS is a paretic and not an apraxic disorder and is not characterized by language disturbances. Its clinical features prove divergent corticobulbar pathways for voluntary and automatic motor control of craniofacial muscles. Precise clinico-neuroradiological correlations should facilitate the identification of the structural substrate of "automatic voluntary dissociation" in FCMS.

  7. Dissociating Stimulus-Driven Semantic and Phonological Effect During Reading and Naming

    PubMed Central

    Mechelli, Andrea; Josephs, Oliver; Lambon Ralph, Matthew A; McClelland, James L; Price, Cathy J

    2007-01-01

    The aim of the present study was to dissociate the neural correlates of semantic and phonological processes during word reading and picture naming. Previous studies have addressed this issue by contrasting tasks involving semantic and phonological decisions. However, these tasks engage verbal short-term memory and executive functions that are not required for reading and naming. Here, 20 subjects were instructed to overtly name written words and pictures of objects while their neuronal responses were measured using functional magnetic resonance imaging (fMRI). Each trial consisted of a pair of successive stimuli that were either semantically related (e.g., “ROBIN-nest”), phonologically related (e.g., “BELL-belt”), unrelated (e.g., “KITE-lobster”), or semantically and phonologically identical (e.g., “FRIDGE-fridge”). In addition, a pair of stimuli could be presented in either the same modality (word-word or picture-picture) or a different modality (word-picture or picture-word). We report that semantically related pairs modulate neuronal responses in a left-lateralized network, including the pars orbitalis of the inferior frontal gyrus, the middle temporal gyrus, the angular gyrus, and the superior frontal gyrus. We propose that these areas are involved in stimulus-driven semantic processes. In contrast, phonologically related pairs modulate neuronal responses in bilateral insula. This region is therefore implicated in the discrimination of similar, competing phonological and articulatory codes. The above effects were detected with both words and pictures and did not differ between the two modalities even with a less conservative statistical threshold. In conclusion, this study dissociates the effects of semantic and phonological relatedness between successive items during reading and naming aloud. Hum Brain Mapp, 2007. © 2006 Wiley-Liss, Inc. PMID:16767767