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Sample records for caffeine markedly enhanced

  1. Caffeine Markedly Enhanced Radiation-Induced Bystander Effects

    NASA Astrophysics Data System (ADS)

    Jiang, Erkang; Wu, Lijun

    2009-04-01

    In this paper it is shown that incubation with 2 mM caffeine enhanced significantly the MN (micronucleus) formation in both the 1 cGy α-particle irradiated and non-irradiated bystander regions. Moreover, caffeine treatment made the non-irradiated bystander cells more sensitive to damage signals. Treated by c-PTIO(2-(4-carboxy-phenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide), a nitric oxide (NO) scavenger, the MN frequencies were effectively inhibited, showing that nitric oxide might be very important in mediating the enhanced damage. These results indicated that caffeine enhanced the low dose α-particle radiation-induced damage in irradiated and non-irradiated bystander regions, and therefore it is important to investigate the relationship between the radiosensitizer and radiation-induced bystander effects (RIBE).

  2. Is caffeine a cognitive enhancer?

    PubMed

    Nehlig, Astrid

    2010-01-01

    The effects of caffeine on cognition were reviewed based on the large body of literature available on the topic. Caffeine does not usually affect performance in learning and memory tasks, although caffeine may occasionally have facilitatory or inhibitory effects on memory and learning. Caffeine facilitates learning in tasks in which information is presented passively; in tasks in which material is learned intentionally, caffeine has no effect. Caffeine facilitates performance in tasks involving working memory to a limited extent, but hinders performance in tasks that heavily depend on working memory, and caffeine appears to rather improve memory performance under suboptimal alertness conditions. Most studies, however, found improvements in reaction time. The ingestion of caffeine does not seem to affect long-term memory. At low doses, caffeine improves hedonic tone and reduces anxiety, while at high doses, there is an increase in tense arousal, including anxiety, nervousness, jitteriness. The larger improvement of performance in fatigued subjects confirms that caffeine is a mild stimulant. Caffeine has also been reported to prevent cognitive decline in healthy subjects but the results of the studies are heterogeneous, some finding no age-related effect while others reported effects only in one sex and mainly in the oldest population. In conclusion, it appears that caffeine cannot be considered a ;pure' cognitive enhancer. Its indirect action on arousal, mood and concentration contributes in large part to its cognitive enhancing properties.

  3. Caffeine Consumption, Expectancies of Caffeine-Enhanced Performance, and Caffeinism Symptoms among University Students.

    ERIC Educational Resources Information Center

    Bradley, John R.; Petree, Allen

    1990-01-01

    Gathered self-report data on college students' (n=797) expectations of caffeine-enhanced performance, level of beverage caffeine consumed daily, and caffeinism signs experienced after consumption of caffeinated beverages. Results supported extending the expectancies model of substance use motivation from alcohol to caffeine. (Author/ABL)

  4. Caffeine Consumption, Expectancies of Caffeine-Enhanced Performance, and Caffeinism Symptoms among University Students.

    ERIC Educational Resources Information Center

    Bradley, John R.; Petree, Allen

    1990-01-01

    Gathered self-report data on college students' (n=797) expectations of caffeine-enhanced performance, level of beverage caffeine consumed daily, and caffeinism signs experienced after consumption of caffeinated beverages. Results supported extending the expectancies model of substance use motivation from alcohol to caffeine. (Author/ABL)

  5. Caffeine and taurine enhance endurance performance.

    PubMed

    Imagawa, T F; Hirano, I; Utsuki, K; Horie, M; Naka, A; Matsumoto, K; Imagawa, S

    2009-07-01

    Caffeine enhances endurance performance; however, its effect on accumulated lactate remains unclear. Conversely, taurine, which also enhances endurance performance, decreases accumulated lactate. In this study, the effect of combination of caffeine and taurine on endurance performance was assessed. Mice ran on a treadmill, and the accumulated lactate was measured. In addition, muscle fibers from the gastrocnemius muscle of the mice were stained with ATPase and analyzed. The use of caffeine and taurine over a 2 week period enhanced endurance performance. Moreover, taurine significantly decreased the accumulated concentration of lactate over long running distances. However, the diameter of the cross-sections and ratios of Types I, IIA, and IIB muscle fibers were not affected.

  6. Caffeine enhances endothelial repair by an AMPK-dependent mechanism.

    PubMed

    Spyridopoulos, Ioakim; Fichtlscherer, Stephan; Popp, Rüdiger; Toennes, Stefan W; Fisslthaler, Beate; Trepels, Thomas; Zernecke, Alma; Liehn, Elisa A; Weber, Christian; Zeiher, Andreas M; Dimmeler, Stefanie; Haendeler, Judith

    2008-11-01

    Migratory capacity of endothelial progenitor cells (EPCs) and mature endothelial cells (ECs) is a key prerequisite for endothelial repair after denuding injury or endothelial damage. We demonstrate that caffeine in physiologically relevant concentrations (50 to 100 micromol/L) induces migration of human EPCs as well as mature ECs. In patients with coronary artery disease (CAD), caffeinated coffee increased caffeine serum concentration from 2 micromol/L to 23 micromol/L, coinciding with a significant increase in migratory activity of patient-derived EPCs. Decaffeinated coffee neither affected caffeine serum levels nor migratory capacity of EPCs. Treatment with caffeine for 7 to 10 days in a mouse-model improved endothelial repair after denudation of the carotid artery. The enhancement of reendothelialization by caffeine was significantly reduced in AMPK knockout mice compared to wild-type animals. Transplantation of wild-type and AMPK(-/-) bone marrow into wild-type mice revealed no difference in caffeine challenged reendothelialization. ECs which were depleted of mitochondrial DNA did not migrate when challenged with caffeine, suggesting a potential role for mitochondria in caffeine-dependent migration. These results provide evidence that caffeine enhances endothelial cell migration and reendothelialization in part through an AMPK-dependent mechanism, suggesting a beneficial role for caffeine in endothelial repair.

  7. Caffeine potentiates the enhancement by choline of striatal acetylcholine release

    NASA Technical Reports Server (NTRS)

    Johnson, D. A.; Ulus, I. H.; Wurtman, R. J.

    1992-01-01

    We investigated the effect of peripherally administered caffeine (50 mg/kg), choline (30, 60, or 120 mg/kg) or combinations of both drugs on the spontaneous release of acetylcholine (ACh) from the corpus striatum of anesthetized rats using in vivo microdialysis. Caffeine alone or choline in the 30 or 60 mg/kg dose failed to increase ACh in microdialysis samples; the 120 mg/kg choline dose significantly enhanced ACh during the 80 min following drug administration. Coadministration of caffeine with choline significantly increased ACh release after each of the choline doses tested. Peak microdialysate levels with the 120 mg/kg dose were increased 112% when caffeine was additionally administered, as compared with 54% without caffeine. These results indicate that choline administration can enhance spontaneous ACh release from neurons, and that caffeine, a drug known to block adenosine receptors on these neurons, can amplify the choline effect.

  8. Caffeine potentiates the enhancement by choline of striatal acetylcholine release

    NASA Technical Reports Server (NTRS)

    Johnson, D. A.; Ulus, I. H.; Wurtman, R. J.

    1992-01-01

    We investigated the effect of peripherally administered caffeine (50 mg/kg), choline (30, 60, or 120 mg/kg) or combinations of both drugs on the spontaneous release of acetylcholine (ACh) from the corpus striatum of anesthetized rats using in vivo microdialysis. Caffeine alone or choline in the 30 or 60 mg/kg dose failed to increase ACh in microdialysis samples; the 120 mg/kg choline dose significantly enhanced ACh during the 80 min following drug administration. Coadministration of caffeine with choline significantly increased ACh release after each of the choline doses tested. Peak microdialysate levels with the 120 mg/kg dose were increased 112% when caffeine was additionally administered, as compared with 54% without caffeine. These results indicate that choline administration can enhance spontaneous ACh release from neurons, and that caffeine, a drug known to block adenosine receptors on these neurons, can amplify the choline effect.

  9. Caffeine enhancement of saccharin but not cyclamate flavor avoidance.

    PubMed

    Mason, J R; Bean, N J

    1987-01-01

    The present experiments were designed to assess whether caffeine, a substance that potentiates human perception of some artificial sweeteners, might also enhance perception of such substances by rats. In Experiment 1, rats were given varied concentrations of saccharin, cyclamate, and caffeine in 2-choice tests. 'Indifference thresholds' for these substances were 3.9 X 10(-4) M, 1 X 10(-3) M, and 1.6 X 10(-7) M, respectively. In Experiment 2, concentrations of saccharin and cyclamate just above and below indifference were used as stimuli in a flavor avoidance learning (FAL) paradigm. 'Suprathreshold' concentrations of saccharin and cyclamate produced reliable FAL while 'subthreshold' concentrations did not. In Experiment 3, rats were exposed to a low concentration of caffeine followed by presentations of subthreshold concentrations of saccharin or cyclamate as stimuli in a FAL paradigm. Saccharin FAL was observed but cyclamate FAL was not, suggesting that caffeine preexposure selectively potentiated detection of saccharin. In Experiment 4, animals were given saccharin or cyclamate with or without prior exposure to caffeine in a FAL paradigm. During subsequent tests, animals were presented with saccharin or cyclamate following exposure to caffeine saccharin or cyclamate mixed with caffeine saccharin or cyclamate alone. Saccharin FAL was observed following caffeine preexposure, but mixing with caffeine had no effect. These findings of selective potentiation are consistent with previous studies of human sensitivity after caffeine preexposure. Moreover, the present results support the notion that inhibitory A1 adenosine receptors are involved in modulating the perceived intensity of some flavors.

  10. Caffeine enhances micturition through neuronal activation in micturition centers.

    PubMed

    Cho, Young-Sam; Ko, Il-Gyu; Kim, Sung-Eun; Hwan, Lakkyong; Shin, Mal-Soon; Kim, Chang-Ju; Kim, Sang-Hoon; Jin, Jun-Jang; Chung, Jun-Young; Kim, Khae-Hawn

    2014-12-01

    Caffeine may promote incontinence through its diuretic effect, particularly in individuals with underlying detrusor overactivity, in addition to increasing muscle contraction of the bladder smooth muscle. Caffeine may also affect bladder function via central micturition centers, including the medial preoptic area, ventrolateral periaqueductal gray, and pontine micturition center. However, the biochemical mechanisms of caffeine in central micturition centers affecting bladder function remain unclear. In the present study, the effects of caffeine on the central micturition reflex were investigated by measuring the degree of neuronal activation, and by quantifying nerve growth factor (NGF) expression in rats. Following caffeine administration for 14 days, a urodynamic study was performed to assess the changes to bladder function. Subsequently, immunohistochemical staining to identify the expression of c‑Fos and NGF in the central micturition areas was performed. Ingestion of caffeine increased bladder smooth muscle contraction pressure and time as determined by cystometry. Expression levels of c‑Fos and NGF in all central micturition areas were significantly increased following the administration of caffeine. The effects on contraction pressure and time were the most potent and expression levels of c‑Fos and NGF were greatest at the lowest dose of caffeine. These results suggest that caffeine facilitates bladder instability through enhancing neuronal activation in the central micturition areas.

  11. The Use of Caffeinated Substances by Surgeons for Cognitive Enhancement.

    PubMed

    Franke, Andreas G; Bagusat, Christiana; McFarlane, Carolyn; Tassone-Steiger, Teresina; Kneist, Werner; Lieb, Klaus

    2015-06-01

    To investigate the use of coffee, caffeinated drinks, and caffeine tablets for pharmacological cognitive enhancement (CE) among surgeons. Surgeons have demanding workloads, and the resulting fatigue and concentration deficits can lead to medical errors. Some surgeons use substances that promote wakefulness to counteract these effects. A total of 3306 surgeons who attended 5 international conferences in 2011 were surveyed regarding their use of coffee, caffeinated drinks, and caffeine tablets for CE and potential factors derived from professional and private life using an anonymous self-report questionnaire. In this study, we were only interested in surgeons working in hospitals; therefore, 951 questionnaires were statistically analyzed. The most prevalent reason for using caffeine of any kind was to reduce fatigue (54.3%). Further prevalent reasons are working the night shift (32.2%) and overly long and excessive work hours (31.7%). Lifetime, past-year, past-month, and past-week prevalence was 66.8%, 61.9%, 56.9%, and 50.5%, for coffee use; 24.2%, 15.4%, 9.9%, and 6.1%, for caffeinated drinks; and 12.6%, 5.9%, 4.7%, and 3.8%, respectively, for caffeine tablets. Caffeine use was associated with lower age, male sex, divorced marital status, living with children, lack of satisfaction with professional status, pressure to perform in private life, and pressure perceived to be harmful to one's own health. Surgeons often use caffeinated substances to cope with fatigue and long working hours. Coffee use was more prevalent than the use of caffeinated drinks and caffeine tablets.

  12. Caffeine accelerates absorption and enhances the analgesic effect of acetaminophen.

    PubMed

    Renner, Bertold; Clarke, Geoff; Grattan, Tim; Beisel, Angelika; Mueller, Christian; Werner, Ulrike; Kobal, Gerd; Brune, Kay

    2007-06-01

    The aim of this study was to determine the analgesic effect of acetaminophen compared to a combination of both caffeine and acetaminophen or caffeine alone using tonic and phasic pain stimulation. Twenty-four subjects were treated orally with 1000 mg acetaminophen, 130 mg caffeine, and a combination of both in a 4-way crossover, double-blind, placebo-controlled study. Pharmacokinetics and analgesic effects were assessed by means of an experimental pain model based on pain-related cortical potentials after phasic stimulation of the nasal mucosa with CO(2) and based on pain ratings after tonic stimulation with dry air. Analgesic effects of acetaminophen and acetaminophen plus caffeine but not caffeine alone caused a significant reduction of pain-related cortical potentials beginning 30 minutes after medication. The combination demonstrated an enhanced effect throughout the observation time up to 3 hours. Caffeine accelerated acetaminophen absorption, indicated by enhanced early AUCs. Significant analgesic effects of the combination on tonic pain ratings were found throughout the observation time as compared to acetaminophen and placebo. In this study, caffeine enhanced and prolonged the analgesic activity of acetaminophen.

  13. Caffeine

    MedlinePlus

    ... medicines for alertness contain synthetic caffeine. So do energy drinks and "energy-boosting" gums and snacks. Most people consume caffeine ... of cola: 35-45 mg An 8-ounce energy drink: 70-100 mg An 8-ounce cup ...

  14. Caffeine use by children: the quest for enhancement.

    PubMed

    Bramstedt, Katrina A

    2007-01-01

    Fair play, both in academics and sports, is a concept that is challenged by the notion of performance enhancement. Both cognitive and physical performance can be viewed as potentially enhanceable, and arguments can be made that enhancement can serve two purposes: gaining an edge or keeping up with others (who may or may not have used performance-enhancing substances). Caffeine, a central nervous system and cardiac stimulant, is frequently used by children for both academic and athletic performance enhancement. In fact, the marketplace contains a plethora of caffeinated products marketed directly to children. This article examines safety and ethical issues associated with the use of caffeine by children and explores the question: Can cognitive performance enhancement be ethically permissible if sports performance enhancement is not?

  15. Caffeine: cognitive and physical performance enhancer or psychoactive drug?

    PubMed

    Cappelletti, Simone; Piacentino, Daria; Daria, Piacentino; Sani, Gabriele; Aromatario, Mariarosaria

    2015-01-01

    Caffeine use is increasing worldwide. The underlying motivations are mainly concentration and memory enhancement and physical performance improvement. Coffee and caffeine-containing products affect the cardiovascular system, with their positive inotropic and chronotropic effects, and the central nervous system, with their locomotor activity stimulation and anxiogenic-like effects. Thus, it is of interest to examine whether these effects could be detrimental for health. Furthermore, caffeine abuse and dependence are becoming more and more common and can lead to caffeine intoxication, which puts individuals at risk for premature and unnatural death. The present review summarizes the main findings concerning caffeine's mechanisms of action (focusing on adenosine antagonism, intracellular calcium mobilization, and phosphodiesterases inhibition), use, abuse, dependence, intoxication, and lethal effects. It also suggests that the concepts of toxic and lethal doses are relative, since doses below the toxic and/or lethal range may play a causal role in intoxication or death. This could be due to caffeine's interaction with other substances or to the individuals' preexisting metabolism alterations or diseases.

  16. Caffeine enhances upper body strength in resistance-trained women

    PubMed Central

    2010-01-01

    Background Research has indicated that low-to-moderate dosages of caffeine supplementation are ergogenic for sustained endurance efforts as well as high-intensity exercise. The effects of caffeine supplementation on strength-power performance are equivocal, with some studies indicating a benefit and others demonstrating no change in performance. The majority of research that has examined the effects of caffeine supplementation on strength-power performance has been carried out in both trained and untrained men. Therefore, the purpose of this study was to determine the acute effects of caffeine supplementation on strength and muscular endurance in resistance-trained women. Methods In a randomized manner, 15 women consumed caffeine (6 mg/kg) or placebo (PL) seven days apart. Sixty min following supplementation, participants performed a one-repetition maximum (1RM) barbell bench press test and repetitions to failure at 60% of 1RM. Heart rate (HR) and blood pressure (BP) were assessed at rest, 60 minutes post-consumption, and immediately following completion of repetitions to failure. Results Repeated measures ANOVA indicated a significantly greater bench press maximum with caffeine (p ≤ 0.05) (52.9 ± 11.1 kg vs. 52.1 ± 11.7 kg) with no significant differences between conditions in 60% 1RM repetitions (p = 0.81). Systolic blood pressure was significantly greater post-exercise, with caffeine (p < 0.05) (116.8 ± 5.3 mmHg vs. 112.9 ± 4.9 mmHg). Conclusions These findings indicate a moderate dose of caffeine may be sufficient for enhancing strength performance in resistance-trained women. PMID:20470411

  17. Caffeine in floral nectar enhances a pollinator's memory of reward.

    PubMed

    Wright, G A; Baker, D D; Palmer, M J; Stabler, D; Mustard, J A; Power, E F; Borland, A M; Stevenson, P C

    2013-03-08

    Plant defense compounds occur in floral nectar, but their ecological role is not well understood. We provide evidence that plant compounds pharmacologically alter pollinator behavior by enhancing their memory of reward. Honeybees rewarded with caffeine, which occurs naturally in nectar of Coffea and Citrus species, were three times as likely to remember a learned floral scent as were honeybees rewarded with sucrose alone. Caffeine potentiated responses of mushroom body neurons involved in olfactory learning and memory by acting as an adenosine receptor antagonist. Caffeine concentrations in nectar did not exceed the bees' bitter taste threshold, implying that pollinators impose selection for nectar that is pharmacologically active but not repellent. By using a drug to enhance memories of reward, plants secure pollinator fidelity and improve reproductive success.

  18. Caffeine

    MedlinePlus

    ... and elevates mood. Caffeine is in tea, coffee, chocolate, many soft drinks, and pain relievers and other ... 70 mg* Cocoa beverage 5 ounces 4 mg* Chocolate milk beverage 8 ounces 5 mg* Dark chocolate ...

  19. Caffeine

    MedlinePlus

    ... and elevates mood. Caffeine is in tea, coffee, chocolate, many soft drinks, and pain relievers and other ... 70 mg* Cocoa beverage 5 ounces 4 mg* Chocolate milk beverage 8 ounces 5 mg* Dark chocolate ...

  20. Caffeine.

    PubMed

    Timson, J

    1977-01-01

    Most of the population of the world is exposed to caffeine to a greater or lesser extent since it occurs in a number of plants used in the preparation of widely consumed drinks, and has in addition a limited therapeutic use. Chromosomal abnormalities are induced by caffeine in both plant cells and in mammalian cells in culture and it also has some anti-mitotic activity. DNA-repair processes sensitive to caffeine have been demonstrated in a number of cell systems and it has been shown to affect a wide range of other cellular processes. Caffeine has potent mutagenic effects in Escherichia coli and other micro-organisms both when acting alone and in combination with other mutagens. However its mutagenic activity in Drosophila has been disputed and the available evidence suggests that it is neither mutagenic in mammals nor synergistic with other mutagens although at very high doses it appears to have some teratogenic activity in mammals.

  1. Use of coffee, caffeinated drinks and caffeine tablets for cognitive enhancement in pupils and students in Germany.

    PubMed

    Franke, A G; Christmann, M; Bonertz, C; Fellgiebel, A; Huss, M; Lieb, K

    2011-11-01

    Substance use for cognitive enhancement (CE) is a topic of increasing importance. There are only few data about substances, prevalence rates and factors associated with CE. The aim of this study was to assess first data about the use of coffee, caffeinated drinks and caffeine tablets for CE at school and university. A self-report questionnaire was developed to analyze 1 547 pupils and students about their use of coffee, caffeine tablets, and caffeinated drinks for CE and factors associated with this use. Lifetime, past-year, and past-month prevalence for the use of coffee for CE was 53.2%, 8.5%, and 6.3%, for the use of caffeinated drinks 39%, 10.7%, and 6.3%, and for the use of caffeine tablets 10.5%, 3.8%, and 0.8%. Use of caffeinated substances for CE was influenced by gender and school grades. The use of coffee and caffeinated drinks for CE was found to be widespread in the surveyed population. Although the use of caffeine tablets was found to be smaller than the above-mentioned means, it still indicates a relatively high disposition for using tablets for purposes of CE. © Georg Thieme Verlag KG Stuttgart · New York.

  2. Caffeine: Cognitive and Physical Performance Enhancer or Psychoactive Drug?

    PubMed Central

    Cappelletti, Simone; Daria, Piacentino; Sani, Gabriele; Aromatario, Mariarosaria

    2015-01-01

    Caffeine use is increasing worldwide. The underlying motivations are mainly concentration and memory enhancement and physical performance improvement. Coffee and caffeine-containing products affect the cardiovascular system, with their positive inotropic and chronotropic effects, and the central nervous system, with their locomotor activity stimulation and anxiogenic-like effects. Thus, it is of interest to examine whether these effects could be detrimental for health. Furthermore, caffeine abuse and dependence are becoming more and more common and can lead to caffeine intoxication, which puts individuals at risk for premature and unnatural death. The present review summarizes the main findings concerning caffeine’s mechanisms of action (focusing on adenosine antagonism, intracellular calcium mobilization, and phosphodiesterases inhibition), use, abuse, dependence, intoxication, and lethal effects. It also suggests that the concepts of toxic and lethal doses are relative, since doses below the toxic and/or lethal range may play a causal role in intoxication or death. This could be due to caffeine’s interaction with other substances or to the individuals' preexisting metabolism alterations or diseases. PMID:26074744

  3. Caffeine and ephedrine: physiological, metabolic and performance-enhancing effects.

    PubMed

    Magkos, Faidon; Kavouras, Stavros A

    2004-01-01

    Preparations containing caffeine and ephedrine have become increasingly popular among sportspersons in recent years as a means to enhance athletic performance. This is due to a slowly accumulating body of evidence suggesting that combination of the two drugs may be more efficacious than each one alone. Caffeine is a compound with documented ergogenicity in various exercise modalities, while ephedrine and related alkaloids have not been shown, as yet, to result in any significant performance improvements. Caffeine-ephedrine mixtures, however, have been reported in several instances to confer a greater ergogenic benefit than either drug by itself. Although data are limited and heterogeneous in nature to allow for reaching consensus, the increase in performance is a rather uniform finding as it has been observed during submaximal steady-state aerobic exercise, short- and long-distance running, maximal and supramaximal anaerobic cycling, as well as weight lifting. From the metabolic point of view, combined ingestion of caffeine and ephedrine has been observed to increase blood glucose and lactate concentrations during exercise, wheareas qualitatively similar effects on lipid fuels (free fatty acids and glycerol) are less pronounced. In parallel, epinephrine and dopamine concentrations are significantly increased, wheareas the effects on norepinephrine are less clear. With respect to pulmonary gas exchange during short-term intense exercise, no physiologically significant effects have been reported following ingestion of caffeine, ephedrine or their combination. Yet, during longer and/or more demanding efforts, some sporadic enhancements have indeed been shown. On the other hand, a relatively consistent cardiovascular manifestation of the latter preparation is an increase in heart rate, in addition to that caused by exercise alone. Finally, evidence to date strongly suggests that caffeine and ephedrine combined are quite effective in decreasing the rating of perceived

  4. Methylphenidate, modafinil, and caffeine for cognitive enhancement in chess: A double-blind, randomised controlled trial.

    PubMed

    Franke, Andreas G; Gränsmark, Patrik; Agricola, Alexandra; Schühle, Kai; Rommel, Thilo; Sebastian, Alexandra; Balló, Harald E; Gorbulev, Stanislav; Gerdes, Christer; Frank, Björn; Ruckes, Christian; Tüscher, Oliver; Lieb, Klaus

    2017-03-01

    Stimulants and caffeine have been proposed for cognitive enhancement by healthy subjects. This study investigated whether performance in chess - a competitive mind game requiring highly complex cognitive skills - can be enhanced by methylphenidate, modafinil or caffeine. In a phase IV, randomized, double-blind, placebo-controlled trial, 39 male chess players received 2×200mg modafinil, 2×20mg methylphenidate, and 2×200mg caffeine or placebo in a 4×4 crossover design. They played twenty 15-minute games during two sessions against a chess program (Fritz 12; adapted to players' strength) and completed several neuropsychological tests. Marked substance effects were observed since all three substances significantly increased average reflection time per game compared to placebo resulting in a significantly increased number of games lost on time with all three treatments. Treatment effects on chess performance were not seen if all games (n=3059) were analysed. Only when controlling for game duration as well as when excluding those games lost on time, both modafinil and methylphenidate enhanced chess performance as demonstrated by significantly higher scores in the remaining 2876 games compared to placebo. In conjunction with results from neuropsychological testing we conclude that modifying effects of stimulants on complex cognitive tasks may in particular result from more reflective decision making processes. When not under time pressure, such effects may result in enhanced performance. Yet, under time constraints more reflective decision making may not improve or even have detrimental effects on complex task performance.

  5. Acute Caffeine Consumption Enhances the Executive Control of Visual Attention in Habitual Consumers

    ERIC Educational Resources Information Center

    Brunye, Tad T.; Mahoney, Caroline R.; Lieberman, Harris R.; Giles, Grace E.; Taylor, Holly A.

    2010-01-01

    Recent work suggests that a dose of 200-400mg caffeine can enhance both vigilance and the executive control of visual attention in individuals with low caffeine consumption profiles. The present study seeks to determine whether individuals with relatively high caffeine consumption profiles would show similar advantages. To this end, we examined…

  6. Acute Caffeine Consumption Enhances the Executive Control of Visual Attention in Habitual Consumers

    ERIC Educational Resources Information Center

    Brunye, Tad T.; Mahoney, Caroline R.; Lieberman, Harris R.; Giles, Grace E.; Taylor, Holly A.

    2010-01-01

    Recent work suggests that a dose of 200-400mg caffeine can enhance both vigilance and the executive control of visual attention in individuals with low caffeine consumption profiles. The present study seeks to determine whether individuals with relatively high caffeine consumption profiles would show similar advantages. To this end, we examined…

  7. Effects of caffeine are more marked on daytime recovery sleep than on nocturnal sleep.

    PubMed

    Carrier, Julie; Fernandez-Bolanos, Marta; Robillard, Rébecca; Dumont, Marie; Paquet, Jean; Selmaoui, Brahim; Filipini, Daniel

    2007-04-01

    Caffeine is often used to counteract sleepiness generated by sleep deprivation, jet lag, and shift-work, and is consumed at different times of day. Caffeine also has effects on sleep. However, little is known about the interaction between sleep deprivation, circadian timing, and caffeine consumption on sleep. In this study, we compared the effects of caffeine on nocturnal sleep initiated at habitual circadian time and on daytime recovery sleep. Thirty-four moderate caffeine consumers participated in both caffeine (200 mg) and placebo (lactose) conditions in a double-blind crossover design. Seventeen subjects followed their habitual sleep-wake cycle and slept in the laboratory during the night (Night), while 17 subjects were sleep deprived for one night and recovery sleep started in the morning (DayRec). All subjects received a capsule of 100 mg of caffeine (or placebo) 3 h before bedtime, and the remaining dose 1 h before bedtime. Compared to placebo, caffeine lengthened sleep latency, increased stage 1, and reduced stage 2 and slow-wave sleep (SWS) in both groups. However, caffeine reduced sleep efficiency more strongly in the DayRec group, and decreased sleep duration and REM sleep only in that group. The stronger effects of caffeine on daytime recovery sleep compared to nocturnal sleep are probably the consequence of the combined influence of increasing circadian wake propensity drive and the dissipation of homeostatic sleep pressure. We propose that the reduction of SWS by caffeine during daytime sleep increases the impact of the circadian wake signal on sleep. These results have implications for individuals using caffeine during night time.

  8. Acute caffeine consumption enhances the executive control of visual attention in habitual consumers.

    PubMed

    Brunyé, Tad T; Mahoney, Caroline R; Lieberman, Harris R; Giles, Grace E; Taylor, Holly A

    2010-12-01

    Recent work suggests that a dose of 200-400 mg caffeine can enhance both vigilance and the executive control of visual attention in individuals with low caffeine consumption profiles. The present study seeks to determine whether individuals with relatively high caffeine consumption profiles would show similar advantages. To this end, we examined the effects of four caffeine doses (0 mg, 100 mg, 200 mg, 400 mg) on low- and high-level visual attention in individuals with high consumption profiles (n=36), in a double-blind study using a repeated measures design. Results from the Attention Network Test indicated that caffeine enhanced both vigilance and the executive control of visual attention, but only at the highest administered dose (400 mg). We demonstrate that in habitual consumers high doses of caffeine can produce beneficial changes in visual attention. These results carry implications for the theorized interactions between caffeine, adenosine and dopamine in brain regions mediating visual attention.

  9. Caffeine, but not nicotine, enhances visual feature binding.

    PubMed

    Colzato, Lorenza S; Fagioli, Sabrina; Erasmus, Vicki; Hommel, Bernhard

    2005-01-01

    The distributed organization of the human visual cortex calls for a mechanism that integrates and binds the features of a perceived event, and neural synchronization is a prime candidate to serve that purpose. Animal studies suggest that synchronization in the visual cortex is enhanced by the muscarinic cholinergic system. Here we show that in healthy humans the binding of shape and colour, and of shape and location, of visual objects is increased by stimulating the muscarinic cholinergic system (caffeine consumption) but not by stimulating the nicotinic cholinergic system (nicotine consumption). Binding across perception and action is unaffected by either manipulation, suggesting a specific link between the visual system and the muscarinic cholinergic system.

  10. Caffeine as an attention enhancer: reviewing existing assumptions.

    PubMed

    Einöther, Suzanne J L; Giesbrecht, Timo

    2013-01-01

    Despite the large number of studies on the behavioural effects of caffeine, an unequivocal conclusion had not been reached. In this review, we seek to disentangle a number of questions. Whereas there is a general consensus that caffeine can improve performance on simple tasks, it is not clear whether complex tasks are also affected, or if caffeine affects performance of the three attention networks (alerting, orienting and executive control). Other questions being raised in this review are whether effects are more pronounced for higher levels of caffeine, are influenced by habitual caffeine use and whether there effects are due to withdrawal reversal. Literature review of double-blind placebo controlled studies that assessed acute effects of caffeine on attention tasks in healthy adult volunteers. Caffeine improves performance on simple and complex attention tasks, and affects the alerting, and executive control networks. Furthermore, there is inconclusive evidence on dose-related performance effects of caffeine, or the influence of habitual caffeine consumption on the performance effects of caffeine. Finally, caffeine's effects cannot be attributed to withdrawal reversal. Evidence shows that caffeine has clear beneficial effects on attention, and that the effects are even more widespread than previously assumed.

  11. The effect of caffeine on repair in Chlamydomonas reinhardtii. I. Enhancement of recombination repair.

    PubMed

    Rosen, H; Rehn, M M; Johnson, B A

    1980-05-01

    The effect of caffeine on repair was studied in the green alga Chlamydomonas reinhardtii. Treatment of UV-irradiated wild-type (UVS+) cells with a sublethal level of caffeine caused a significant increase in survival compared to untreated UV-irradiated cells. Caffeine did not affect survival in the repair-deficient strain UVSE1, which is deficient in repair of UV-induced damage carried out by enzymes associated with recombination during meiosis. A significant increase in survival in the presence of caffeine was observed in the repair-deficient strain UVSE4 in which recombination during meiosis is not affected. Treatment of zygotes homozygous for UVS+, UVSE1, or UVSE4 with sublethal levels of caffeine caused marked increases in recombination frequency in UVS+ and UVSE4 zygotes and no increase in recombination in UVSE1 zygotes. These results indicate that caffeine increases recombination in normal strains. Increased opportunity for recombination caused by caffeine would not result in increased recombination frequency in the UVSE1 strain, assuming limited-recombination enzyme activity in this strain. The observed increase in survival following UV-irradiation in the presence of caffeine in strains having normal recombination would therefore be associated with a caffeine-induced increase in opportunities for recombination repair.

  12. Chronic caffeine treatment enhances the resilience to social defeat stress in mice.

    PubMed

    Yin, Yong-Qin; Zhang, Chun; Wang, Jian-Xin; Hou, Jia; Yang, Xu; Qin, Jing

    2015-02-01

    Strong evidence has shown that caffeine exerts antidepressant-like effects in chronic stress situations by increasing dopamine levels. However, whether caffeine mediates the dopaminergic system and interferes with the resilience to social defeat stress in mice is unknown. The aim of this study is to investigate the role of caffeine in the behavioral responses to social defeat stress and the possible regulatory role of the dopaminergic system. Mice experienced chronic social defeat stress for 10 days. Caffeine was administered intraperitoneally before, during and after social defeat stress. The time spent in interaction zone, social interaction ratio and sucrose preference test was used to measure the social avoidance and anhedonia in mice. The results showed that chronic pretreatment with caffeine for 14 days and for 10 days during stress reversed the avoidance of social behavior and anhedonia induced by social defeat stress in mice, suggesting the enhancement of the resilience to social defeat stress induced by caffeine. However, neither the treatment with caffeine only during the social defeat stress for 10 days nor the treatment with acute caffeine after defeat stress altered the resilience to stress. Furthermore, chronic caffeine treatment did not affect the normal locomotor activity and the desperate behavior in naïve mice. Moreover, the antagonism of dopamine D1 receptor and not D2 receptor reversed the effect of caffeine on the social avoidance and depressive-like behavior. Finally, pretreatment with higher doses of caffeine did not affect the behavioral response to social defeat stress. Taken together, our findings provide new insight into the effects of caffeine on social avoidance and anhedonia in mice. In addition, our results illustrated the value of measuring changes in depressive-like behavior before and after social defeat stress to determine the potential treatment of caffeine on depression through the regulation of dopaminergic system.

  13. Enhancement of nootropic effect of duloxetine and bupropion by caffeine in mice.

    PubMed

    Kale, Pravin Popatrao; Addepalli, Veeranjaneyulu

    2015-01-01

    The existing evidence suggests an association between depression and memory impairment. The objective of present study was to assess the effect of low dose caffeine with duloxetine and bupropion on memory. Mice were divided randomly into seven groups. Intra-peritoneal treatment of normal saline (10 ml/kg), caffeine (10 mg/kg), duloxetine (10 mg/kg), bupropion alone (10 mg/kg), caffeine + duloxetine (5 mg/kg, each), caffeine + bupropion (5 mg/kg, each), and bupropion + duloxetine (5 mg/kg, each) were given to groups I-VII, respectively. Elevated plus maze was used to evaluate transfer latency (TL) and Morris water maze was used to estimate the time spent in target quadrant. Caffeine with duloxetine treated group was better than other combination treated groups in terms of a significant decrease in TL and increase in the time spent in target quadrant recorded. Combining lower dose of caffeine with duloxetine may enhance cognitive benefits than respective monotherapies.

  14. Acute stress blocks the caffeine-induced enhancement of contextual memory retrieval in mice.

    PubMed

    Pierard, Chistophe; Krazem, Ali; Henkous, Nadia; Decorte, Laurence; Béracochéa, Daniel

    2015-08-15

    This study investigated in mice the dose-effect of caffeine on memory retrieval in non-stress and stress conditions. C57 Bl/6 Jico mice learned two consecutive discriminations (D1 and D2) in a four-hole board which involved either distinct contextual (CSD) or similar contextual (SSD) cues. All mice received an i.p. injection of vehicle or caffeine (8, 16 or 32mg/kg) 30min before the test session. Results showed that in non-stress conditions, the 16mg/kg caffeine dose induced a significant enhancement of D1 performance in CSD but not in SSD. Hence, we studied the effect of an acute stress (electric footshocks) administered 15min before the test session on D1 performance in caffeine-treated mice. Results showed that stress significantly decreased D1 performance in vehicle-treated controls and the memory-enhancing effect induced by the 16mg/kg caffeine dose in non-stress condition is no longer observed. Interestingly, whereas caffeine-treated mice exhibited weaker concentrations of plasma corticosterone as compared to vehicles in non-stress condition, stress significantly increased plasma corticosterone concentrations in caffeine-treated mice which reached similar level to that of controls. Overall, the acute stress blocked both the endocrinological and memory retrieval enhancing effects of caffeine.

  15. No Enhancement of 24-Hour Visuomotor Skill Retention by Post-Practice Caffeine Administration

    PubMed Central

    Hussain, Sara J.; Cole, Kelly J.

    2015-01-01

    Caffeine is widely consumed throughout the world and appears to indirectly facilitate learning and memory through effects on attention and motivation. Animal work indicates that post-training caffeine administration augments inhibitory avoidance memory, spatial memory, and object memory. In humans, post-training caffeine administration enhances the ability to discern between familiar images and new, similar images. However, the effect of post-training caffeine administration on motor memory has not been examined. Therefore, we tested two groups of low caffeine consumers (average weekly consumption ≤500 mg) in a double-blind, placebo-controlled study involving acquisition of a continuous isometric visuomotor tracking skill. On Day 1, subjects completed 5 blocks (150 repetitions) of training on the continuous isometric visuomotor skill and subsequently ingested either 200 mg of caffeine or placebo. On day 2, subjects completed an additional 5 blocks of training. Day 1 mean performance and performance variability were both similar between groups, suggesting that both groups acquired the motor skill similarly. For mean performance on Day 2, patterns of re-learning, mean performance learning magnitudes, mean performance learning rates, and mean performance retention magnitudes were all similar between groups. For performance variability on Day 2, there was a small trend towards increased variability in the caffeine group during re-learning, but performance variability learning magnitudes and performance variability retention magnitudes did not differ between groups. Because motor skill acquisition can also be conceptualized as a reduction in performance variability, these results suggest that there may be a small negative effect of post-practice caffeine administration on memory of a newly-learned visuomotor skill. Overall, we found no evidence to suggest that post-training caffeine administration enhances 24-hour retention of a newly-learned continuous visuomotor

  16. No Enhancement of 24-Hour Visuomotor Skill Retention by Post-Practice Caffeine Administration.

    PubMed

    Hussain, Sara J; Cole, Kelly J

    2015-01-01

    Caffeine is widely consumed throughout the world and appears to indirectly facilitate learning and memory through effects on attention and motivation. Animal work indicates that post-training caffeine administration augments inhibitory avoidance memory, spatial memory, and object memory. In humans, post-training caffeine administration enhances the ability to discern between familiar images and new, similar images. However, the effect of post-training caffeine administration on motor memory has not been examined. Therefore, we tested two groups of low caffeine consumers (average weekly consumption ≤500 mg) in a double-blind, placebo-controlled study involving acquisition of a continuous isometric visuomotor tracking skill. On Day 1, subjects completed 5 blocks (150 repetitions) of training on the continuous isometric visuomotor skill and subsequently ingested either 200 mg of caffeine or placebo. On day 2, subjects completed an additional 5 blocks of training. Day 1 mean performance and performance variability were both similar between groups, suggesting that both groups acquired the motor skill similarly. For mean performance on Day 2, patterns of re-learning, mean performance learning magnitudes, mean performance learning rates, and mean performance retention magnitudes were all similar between groups. For performance variability on Day 2, there was a small trend towards increased variability in the caffeine group during re-learning, but performance variability learning magnitudes and performance variability retention magnitudes did not differ between groups. Because motor skill acquisition can also be conceptualized as a reduction in performance variability, these results suggest that there may be a small negative effect of post-practice caffeine administration on memory of a newly-learned visuomotor skill. Overall, we found no evidence to suggest that post-training caffeine administration enhances 24-hour retention of a newly-learned continuous visuomotor

  17. Synergistic Skin Penetration Enhancer and Nanoemulsion Formulations Promote the Human Epidermal Permeation of Caffeine and Naproxen.

    PubMed

    Abd, Eman; Namjoshi, Sarika; Mohammed, Yousuf H; Roberts, Michael S; Grice, Jeffrey E

    2016-01-01

    We examined the extent of skin permeation enhancement of the hydrophilic drug caffeine and lipophilic drug naproxen applied in nanoemulsions incorporating skin penetration enhancers. Infinite doses of fully characterized oil-in-water nanoemulsions containing the skin penetration enhancers oleic acid or eucalyptol as oil phases and caffeine (3%) or naproxen (2%) were applied to human epidermal membranes in Franz diffusion cells, along with aqueous control solutions. Caffeine and naproxen fluxes were determined over 8 h. Solute solubility in the formulations and in the stratum corneum (SC), as well as the uptake of product components into the SC were measured. The nanoemulsions significantly enhanced the skin penetration of caffeine and naproxen, compared to aqueous control solutions. Caffeine maximum flux enhancement was associated with a synergistic increase in both caffeine SC solubility and skin diffusivity, whereas a formulation-increased solubility in the SC was the dominant determinant for increased naproxen fluxes. Enhancements in SC solubility were related to the uptake of the formulation excipients containing the active compounds into the SC. Enhanced skin penetration in these systems is largely driven by uptake of formulation excipients containing the active compounds into the SC with impacts on SC solubility and diffusivity.

  18. Fasting activated histaminergic neurons and enhanced arousal effect of caffeine in mice.

    PubMed

    Wang, Yi-Qun; Li, Rui; Wu, Xu; Zhu, Fen; Takata, Yohko; Zhang, Ze; Zhang, Meng-Qi; Li, Shan-Qun; Qu, Wei-Min

    2015-06-01

    Caffeine, a popular psychoactive compound, promotes wakefulness via blocking adenosine A2A receptors in the shell of the nucleus accumbens, which projects to the arousal histaminergic tuberomammillary nucleus (TMN). The TMN controls several behaviors such as wakefulness and feeding. Fasting has been reported to activate the TMN histaminergic neurons to increase arousal. Therefore, we propose that caffeine may promote greater arousal under fasting rather than normal feeding conditions. In the current study, locomotor activity recording, electroencephalogram (EEG) and electromyogram recording and c-Fos expression were used in wild type (WT) and histamine H1 receptor (H1R) knockout (KO) mice to investigate the arousal effects of caffeine under fasting conditions. Caffeine (15mg/kg) enhanced locomotor activity in fasted mice for 5h, but only did so for 3h in normally fed animals. Pretreatment with the H1R antagonist pyrilamine abolished caffeine-induced stimulation on locomotor activity in fasted mice. EEG recordings confirmed that caffeine-induced wakefulness for 3h in fed WT mice, and for 5h in fasted ones. A stimulatory effect of caffeine was not observed in fasted H1R KO mice. Furthermore, c-Fos expression was increased in the TMN under fasting conditions. These results indicate that caffeine had greater wakefulness-promoting effects in fasted mice through the mediation of H1R.

  19. Spectroscopic study of surface enhanced Raman scattering of caffeine on borohydride-reduced silver colloids

    NASA Astrophysics Data System (ADS)

    Chen, Xiaomin; Gu, Huaimin; Shen, Gaoshan; Dong, Xiao; Kang, Jian

    2010-06-01

    The surface enhanced Raman scattering (SERS) of caffeine on borohydride-reduced silver colloids system under different aqueous solution environment has been studied in this paper. The relative intensity of SERS of caffeine significantly varies with different concentrations of sodium chloride and silver particles. However, at too high or too low concentration of sodium chloride and silver particle, the enhancement of SERS spectra is not evident. The SERS spectra of caffeine suggest that the contribution of the charge transfer mechanism to SERS may be dominant. The chloride ions can significantly enhance the efficiency of SERS, while the enhancement is selective, as the efficiency in charge transfer enhancement is higher than in electromagnetic enhancement. Therefore, it can be concluded that the active site of chloride ion locates on the bond between the caffeine and the silver surface. In addition, the SERS spectra of caffeine on borohydride-reduced and citrate-reduced silver colloids are different, which may be due to different states caffeine adsorbed on silver surface under different silver colloids.

  20. Caffeine may enhance orthodontic tooth movement through increasing osteoclastogenesis induced by periodontal ligament cells under compression.

    PubMed

    Yi, Jianru; Yan, Boxi; Li, Meile; Wang, Yu; Zheng, Wei; Li, Yu; Zhao, Zhihe

    2016-04-01

    Caffeine is the kernel component of coffee and has multiple effects on bone metabolism. Here we aimed to investigate the effects of caffeine intake on orthodontic tooth movement (OTM). (1) In the in vivo study, two groups comprising 15 randomly assigned rats each underwent orthodontic treatment. One group ingested caffeine at 25mg/kg body weight per day and the other, plain water. After 3 weeks, the degree of tooth movement and effect on the periodontium were assessed. (2) In the in vitro study, we established a model mimicking the essential bioprocess of OTM, which contained a periodontal ligament tissue model (PDLtm), and a co-culture system of osteoblasts (OBs) and osteoclast precursors (pre-OCs). After being subjected to static compressive force with or without caffeine administration, the conditioned media from the PDLtm were used for the OB/pre-OC co-cultures to induce osteoclastogenesis. (1) In vivo, the caffeine group displayed a significantly greater rate of tooth movement than the control. The alveolar bone mineral density and bone volume fraction were similar between the two groups; however, immunohistochemical staining showed that the caffeine group had significantly more TRAP(+) osteoclasts and higher RANKL expression in the compressed periodontium. (2) In vitro, caffeine at 0.01mM significantly enhanced the compression-induced expression of RANKL and COX-2, as well as prostaglandin E2 production in the PDLtm. Furthermore, the "caffeine+compression"-conditioned media induced significantly more TRAP(+) OC formation when compared with compression alone. Daily intake of caffeine, at least at some specific dosage, may enhance OTM through increasing osteoclastogenesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Caffeine intake improves fructose-induced hypertension and insulin resistance by enhancing central insulin signaling.

    PubMed

    Yeh, Tung-Chen; Liu, Chun-Peng; Cheng, Wen-Han; Chen, Bo-Rong; Lu, Pei-Jung; Cheng, Pei-Wen; Ho, Wen-Yu; Sun, Gwo-Ching; Liou, Jau-Cheng; Tseng, Ching-Jiunn

    2014-03-01

    Recent clinical studies found that fructose intake leads to insulin resistance and hypertension. Fructose consumption promotes protein fructosylation and formation of superoxide. In a previous study, we revealed that inhibition of superoxide production in the nucleus tractus solitarii (NTS) reduces blood pressure. Caffeine displays significant antioxidant ability in protecting membranes against oxidative damage and can lower the risk of insulin resistance. However, the mechanism through which caffeine improves fructose-induced insulin resistance is unclear. The aim of this study was to investigate whether caffeine consumption can abolish superoxide generation to enhance insulin signaling in the NTS, thereby reducing blood pressure in rats with fructose-induced hypertension. Treatment with caffeine for 4 weeks decreased blood pressure, serum fasting glucose, insulin, homeostatic model assessment-insulin resistance, and triglyceride levels and increased the serum direct high-density lipoprotein level in fructose-fed rats but not in control rats. Caffeine treatment resulted in the recovery of fructose-induced decrease in nitric oxide production in the NTS. Immunoblotting and immunofluorescence analyses further showed that caffeine reduced the fructose-induced phosphorylation of insulin receptor substrate 1 (IRS1(S307)) and reversed Akt(S473) and neuronal nitric oxide synthase phosphorylation. Similarly, caffeine was able to improve insulin sensitivity and decrease insulin levels in the NTS evoked by fructose. Caffeine intake also reduced the production of superoxide and expression of receptor of advanced glycation end product in the NTS. These results suggest that caffeine may enhance insulin receptor substrate 1-phosphatidylinositol 3-kinase-Akt-neuronal nitric oxide synthase signaling to decrease blood pressure by abolishing superoxide production in the NTS.

  2. Oral caffeine during voluntary exercise markedly inhibits skin carcinogenesis and decreases inflammatory cytokines in UVB-treated mice

    PubMed Central

    Lou, YouRong; Peng, QingYun; Li, Tao; Nolan, Bonnie; Bernard, Jamie J.; Wagner, George C.; Lin, Yong; Shih, Weichung Joe; Conney, Allan H; Lu, YaoPing

    2013-01-01

    UVB-pretreated SKH-1 mice were treated with water, caffeine (0.1 mg/ml), voluntary running wheel exercise (RW) or caffeine together with RW for 14 weeks. Treatment of the mice with caffeine, RW, or caffeine plus RW decreased skin tumors per mouse by 27, 35 and 62%, and the tumor volume per mouse was decreased by 61, 70 and 85%, respectively. In mechanistic studies, mice were treated with water, caffeine, RW, or caffeine plus RW for 2 weeks prior to a single irradiation with UVB. Caffeine plus RW increased RW activity by 22% when compared with RW alone. Caffeine ingestion was not significantly different between groups. Treatment of mice with caffeine plus RW for 2 weeks decreased the weight of the parametrial fat pads and stimulated the formation of UVB-induced apoptosis to a greater extent than treatment with caffeine or RW alone. An antibody array revealed that caffeine plus RW administered to mice fed a high fat diet and irradiated with UVB decreased the epidermal levels of LIX, sTNFR1 and MIP-1γ. Overall, caffeine during RW exerts a stronger effect than either treatment alone for decreasing tissue fat, increasing UVB-induced apoptosis, lowering the levels of cytokines associated with inflammation and for inhibiting UVB-induced carcinogenesis. PMID:24070239

  3. Oral caffeine during voluntary exercise markedly inhibits skin carcinogenesis and decreases inflammatory cytokines in UVB-treated mice.

    PubMed

    Lou, Yourong; Peng, Qingyun; Li, Tao; Nolan, Bonnie; Bernard, Jamie J; Wagner, George C; Lin, Yong; Shih, Weichung Joe; Conney, Allan H; Lu, Yaoping

    2013-01-01

    Ultraviolet B (UVB)-pretreated SKH-1 mice were treated with water, caffeine (0.1 mg/ml), voluntary running wheel exercise (RW) or caffeine together with RW for 14 wk. Treatment of the mice with caffeine, RW, or caffeine plus RW decreased skin tumors per mouse by 27%, 35%, and 62%, respectively, and the tumor volume per mouse was decreased by 61%, 70%, and 85%, respectively. In mechanistic studies, mice were treated with water, caffeine, RW, or caffeine plus RW for 2 wk prior to a single irradiation with UVB. Caffeine plus RW increased RW activity by 22% when compared with RW alone. Caffeine ingestion was not significantly different between groups. Treatment of mice with caffeine plus RW for 2 wk decreased the weight of the parametrial fat pads and stimulated the formation of UVB-induced apoptosis to a greater extent than treatment with caffeine or RW alone. An antibody array revealed that caffeine plus RW administered to mice fed a high-fat diet and irradiated with UVB decreased the epidermal levels of lipopolysaccharide-induced CXC chemokine, soluble TNF alpha receptor-1, and macrophage inflammatory protein-1γ. Overall, caffeine during RW exerts a stronger effect than either treatment alone for decreasing tissue fat, increasing UVB-induced apoptosis, lowering the levels of cytokines associated with inflammation and for inhibiting UVB-induced carcinogenesis.

  4. Caffeine intake is associated with pupil dilation and enhanced accommodation.

    PubMed

    Abokyi, S; Owusu-Mensah, J; Osei, K A

    2017-04-01

    PurposeIt is purported that caffeine, an autonomic stimulant, affects visual performance. This study sought to assess whether caffeine intake was associated with changes in pupil size and/or amplitude of accommodation.Patients and methodsA double-masked, crossover study was conducted in 50 healthy subjects of age range 19 to 25 years. Subjects were randomized to treatments such that subjects consumed either 250 mg caffeine drink or vehicle on separate days. Amplitude of accommodation was measured by the push-up technique, and pupil size using a millimeter ruler fixed to a slit lamp biomicroscope in dim illumination (5 lux). Amplitude of accommodation and pupil size were taken at baseline, and at 30, 60 and 90 min time points post treatment. Repeated measures one-way ANOVA and paired t-test were used in analyzing data.ResultsAmplitude of accommodation and pupil size after caffeine intake were significantly greater than vehicle (P<0.001) at each time point. Consumption of the caffeine beverage was associated with significant increases in amplitude of accommodation and pupil size with time (P<0.001). Amplitude of accommodation rose from 12.4 (±2.2 D) at baseline to 15.8(±2.6 D) at 90 min. Similarly, pupil size increased from 3.4 (±0.4 mm) at baseline to 4.5 (±0.72 mm) at 90 min. Consumption of vehicle was not associated with increase in amplitude of accommodation or pupil size with time.ConclusionPupil size and accommodation are affected after ingestion of caffeine. This study suggests caffeine may have some influence on visual functions.

  5. Caffeine intake enhances the benefits of sodium glucose transporter 2 inhibitor.

    PubMed

    Hashimoto, Yoshitaka; Tanaka, Muhei; Yamazaki, Masahiro; Nakano, Koji; Ushigome, Emi; Okada, Hiroshi; Oda, Yohei; Nakamura, Naoto; Fukui, Michiaki

    2016-10-01

    The effect of sodium glucose transporter 2 (SGLT-2) inhibitors is dependent on the glomerular filtration rate. It has been reported that caffeine intake increases glomerular filtration rate. However, the effect of caffeine intake on urinary glucose excretion in patients who take SGLT-2 inhibitors is unclear. Six patients with type 2 diabetes took part in a randomized, open-label, crossover pilot study. The patients took SGLT-2 inhibitors (ipragliflozin) for 9 days. On day 3, 6 and 9, the patients were assigned to one of three studies: Water 500, patients drank 500 mL of water in 3 h; Water 1500, patients drank 1500 mL of water in 3 h; and Caffeine 500, patients drank 500 mL of water with 400 mg of caffeine in 3 h. In all of the studies, the patients' urine was collected over a 6-h period. In addition, we enrolled 60 patients with type 2 diabetes who newly took SGLT-2 inhibitors in a 3-month follow-up cohort study to investigate the effect of caffeine intake on glucose control. Caffeine intake was evaluated using questionnaires. The 6-h median (interquartile range) urinary glucose excretion was 9.5 (8.5-9.7) g in Water 500, 12.2 (10.3-27.2) g in Water 1500 and 15.7 (11.4-21.4) g in Caffeine 500 (p = 0.005 vs Water 500). In the cohort study, multiple regression analysis demonstrated that log (caffeine intake) was associated with a change in HbA1c (β = -0.299, p = 0.043) after adjusting for covariates. Caffeine intake enhanced the effect of SGLT-2 inhibitors. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  6. Caffeine enhances the physiological response to occupational stress in medical students.

    PubMed

    Pincomb, G A; Lovallo, W R; Passey, R B; Brackett, D J; Wilson, M F

    1987-01-01

    Caffeine (3.3 mg/kg) was tested against a placebo in 20 male medical students during periods of low (no exams) versus high (final exams) work stress. On each of 8 test days, heart rate and blood pressure were measured at baseline and over a 40-min postdrug interval; immediately afterward, blood was drawn to test plasma cortisol and serum lipid concentrations. Exams increased heart rate (p less than .005) and systolic blood pressure (p less than .02). Caffeine decreased heart rate (p less than .0001) and increased systolic blood pressure (p less than .005), diastolic blood pressure (p less than .0001), plasma cortisol levels (p less than .01), and serum cholesterol levels (p less than .02). Caffeine effects were additive with those of exams, and together they increased the number of men showing systolic blood pressures in the borderline hypertensive range. Thus, caffeine use during periods of increased occupational stress may enhance the cumulative stress response.

  7. Caffeine enhances intramembranous charge movement in frog skeletal muscle by increasing cytoplasmic Ca2+ concentration.

    PubMed Central

    Shirokova, N; Ríos, E

    1996-01-01

    1. Currents of intramembranous charge movement were recorded, together with intracellular [Ca2+], in single muscle fibres subjected to voltage-clamp depolarization and 'pulses' of extracellular solution with a Ca2+ release-inducing concentration of caffeine (10 mM). 2. When caffeine was present prior to and during the voltage pulses, the charge transferred by pulses to between -60 and -40 mV increased by about 40%. 3. In fibres depleted of Ca2+ in the sarcoplasmic reticulum (SR), caffeine had no effect on charge transfer or kinetics. 4. Whenever the prior exposure to caffeine resulted in a large elevation in [Ca2+]i at the start of the depolarizing pulse, there was an increase in I beta, the monotonically decaying component of charge movement. When the presence of caffeine enhanced Ca2+ release induced by the pulse, there was increase in I gamma, the hump-like component. 5. The charge transferred during a pulse to -50 mV increased with time of exposure to caffeine. Ca2+ release induced by the voltage pulse grew during the first second of caffeine exposure, then decreased with longer exposure time. The enhancement of charge transfer by caffeine was therefore not due to the increase in Ca2+ release caused by the drug. 6. The increase in charge transfer was a uniform, monotonically increasing function of the [Ca2+]i attained at the end of the voltage pulse. 7. Charge transfer, as a function of [Ca2+]i, pulse voltage and time, was simulated with a model, used previously, in which Ca2+ binds to intracellular sites and increases the electrical potential near the voltage sensors. Two sites were needed to fit the observations, with dissociation constants of 60 nM and 2 to 10 microM. 8. In the presence of caffeine, the voltage-driven movement of a given amount of intra-membranous charge resulted in greater activation of release permeability. 9. All effects of caffeine observed in this and the preceding paper could be explained assuming a single action: caffeine increases

  8. Voluntary exercise together with oral caffeine markedly stimulates UVB light-induced apoptosis and decreases tissue fat in SKH-1 mice

    PubMed Central

    Lu, Yao-Ping; Nolan, Bonnie; Lou, You-Rong; Peng, Qing-Yun; Wagner, George C.; Conney, Allan H.

    2007-01-01

    Treatment of SKH-1 mice orally with caffeine (0.1 mg/ml in the drinking water), voluntary running wheel exercise, or a combination of caffeine and exercise for 2 weeks (i) decreased the weight of the parametrial fat pads by 35, 62, and 77%, respectively; (ii) decreased the thickness of the dermal fat layer by 38, 42, and 68%, respectively; (iii) stimulated the formation of UVB-induced apoptotic sunburn cells in the epidermis by 96, 120, and 376%, respectively; and (iv) stimulated the formation of UVB-induced caspase 3 (active form)-positive cells in the epidermis by 92, 120, and 389%, respectively (average of two experiments). Oral administration of caffeine (0.4 mg/ml in the drinking water) in combination with voluntary exercise was less effective than administration of the low dose of caffeine in combination with exercise in stimulating UVB-induced apoptosis. Although orally administrated caffeine (0.1 mg/ml in the drinking water) or voluntary exercise for 2 weeks caused only a small nonsignificant stimulation of UVB-induced increase in the percentage of phospho-p53 (Ser-15)-positive cells in the epidermis (27 or 18%, respectively), the combination of the two treatments enhanced the UVB-induced increase in phospho-p53 (Ser-15)-positive cells by 99%. The plasma concentration of caffeine in mice ingesting caffeine (0.1–0.4 mg/ml drinking water) is similar to that in the plasma of most coffee drinkers (one to four cups per day). Our studies indicate a greater than additive stimulatory effect of combined voluntary exercise and oral administration of a low dose of caffeine on UVB-induced apoptosis. PMID:17664435

  9. Voluntary exercise together with oral caffeine markedly stimulates UVB light-induced apoptosis and decreases tissue fat in SKH-1 mice.

    PubMed

    Lu, Yao-Ping; Nolan, Bonnie; Lou, You-Rong; Peng, Qing-Yun; Wagner, George C; Conney, Allan H

    2007-07-31

    Treatment of SKH-1 mice orally with caffeine (0.1 mg/ml in the drinking water), voluntary running wheel exercise, or a combination of caffeine and exercise for 2 weeks (i) decreased the weight of the parametrial fat pads by 35, 62, and 77%, respectively; (ii) decreased the thickness of the dermal fat layer by 38, 42, and 68%, respectively; (iii) stimulated the formation of UVB-induced apoptotic sunburn cells in the epidermis by 96, 120, and 376%, respectively; and (iv) stimulated the formation of UVB-induced caspase 3 (active form)-positive cells in the epidermis by 92, 120, and 389%, respectively (average of two experiments). Oral administration of caffeine (0.4 mg/ml in the drinking water) in combination with voluntary exercise was less effective than administration of the low dose of caffeine in combination with exercise in stimulating UVB-induced apoptosis. Although orally administrated caffeine (0.1 mg/ml in the drinking water) or voluntary exercise for 2 weeks caused only a small nonsignificant stimulation of UVB-induced increase in the percentage of phospho-p53 (Ser-15)-positive cells in the epidermis (27 or 18%, respectively), the combination of the two treatments enhanced the UVB-induced increase in phospho-p53 (Ser-15)-positive cells by 99%. The plasma concentration of caffeine in mice ingesting caffeine (0.1-0.4 mg/ml drinking water) is similar to that in the plasma of most coffee drinkers (one to four cups per day). Our studies indicate a greater than additive stimulatory effect of combined voluntary exercise and oral administration of a low dose of caffeine on UVB-induced apoptosis.

  10. Enhancement of nootropic effect of duloxetine and bupropion by caffeine in mice

    PubMed Central

    Kale, Pravin Popatrao; Addepalli, Veeranjaneyulu

    2015-01-01

    Objective: The existing evidence suggests an association between depression and memory impairment. The objective of present study was to assess the effect of low dose caffeine with duloxetine and bupropion on memory. Materials and Methods: Mice were divided randomly into seven groups. Intra-peritoneal treatment of normal saline (10 ml/kg), caffeine (10 mg/kg), duloxetine (10 mg/kg), bupropion alone (10 mg/kg), caffeine + duloxetine (5 mg/kg, each), caffeine + bupropion (5 mg/kg, each), and bupropion + duloxetine (5 mg/kg, each) were given to groups I-VII, respectively. Elevated plus maze was used to evaluate transfer latency (TL) and Morris water maze was used to estimate the time spent in target quadrant. Results: Caffeine with duloxetine treated group was better than other combination treated groups in terms of a significant decrease in TL and increase in the time spent in target quadrant recorded. Conclusion: Combining lower dose of caffeine with duloxetine may enhance cognitive benefits than respective monotherapies. PMID:25878382

  11. Acute caffeine ingestion enhances performance and dampens muscle pain following resistance exercise to failure.

    PubMed

    Duncan, M J; Oxford, S W

    2012-06-01

    This double-blind, within-subjects experiment examined the effects of acute caffeine ingestion on perceptions of muscle pain following a bout of high-intensity, upper-body resistance exercise to failure. Moderately trained males (N.=18) ingested a dose of caffeine (5 mg · kg-1) or placebo in a randomised and counterbalanced order and 1 hour later completed bench press exercise to failure at an intensity of 60% 1 repetition maximum. Repetitions completed was taken as a measure of performance, peak heart rate was determined via heart rate telemetry during the exercise bout, rating of perceived exertion (RPE) and upper body muscle pain was recorded immediately upon failure of the exercise task and peak blood lactate concentration was determined post-exercise. Caffeine resulted in improved repetitions to failure (t [17]=3.119, P=0.006), greater peak blood lactate (t [17] =5.080, P=0.0001) and lower RPE (t 17=-3.431, P=0.003) compared to placebo. Muscle pain perception was also significantly lower in the caffeine condition compared to placebo (t [17]=-2.567, P=0.04). These results support prior studies using aerobic based exercise modes in suggesting that caffeine ingestion can dampen exercise-induced muscle pain. Specifically, caffeine ingestion enhances muscular strength performance and reduces upper body muscle pain perception immediately following a bout of high-intensity resistance exercise to failure.

  12. Caffeine enhances real-world language processing: evidence from a proofreading task.

    PubMed

    Brunyé, Tad T; Mahoney, Caroline R; Rapp, David N; Ditman, Tali; Taylor, Holly A

    2012-03-01

    Caffeine has become the most prevalently consumed psychostimulant in the world, but its influences on daily real-world functioning are relatively unknown. The present work investigated the effects of caffeine (0 mg, 100 mg, 200 mg, 400 mg) on a commonplace language task that required readers to identify and correct 4 error types in extended discourse: simple local errors (misspelling 1- to 2-syllable words), complex local errors (misspelling 3- to 5-syllable words), simple global errors (incorrect homophones), and complex global errors (incorrect subject-verb agreement and verb tense). In 2 placebo-controlled, double-blind studies using repeated-measures designs, we found higher detection and repair rates for complex global errors, asymptoting at 200 mg in low consumers (Experiment 1) and peaking at 400 mg in high consumers (Experiment 2). In both cases, covariate analyses demonstrated that arousal state mediated the relationship between caffeine consumption and the detection and repair of complex global errors. Detection and repair rates for the other 3 error types were not affected by caffeine consumption. Taken together, we demonstrate that caffeine has differential effects on error detection and repair as a function of dose and error type, and this relationship is closely tied to caffeine's effects on subjective arousal state. These results support the notion that central nervous system stimulants may enhance global processing of language-based materials and suggest that such effects may originate in caffeine-related right hemisphere brain processes. Implications for understanding the relationships between caffeine consumption and real-world cognitive functioning are discussed. PsycINFO Database Record (c) 2012 APA, all rights reserved.

  13. What Users Think about the Differences between Caffeine and Illicit/Prescription Stimulants for Cognitive Enhancement

    PubMed Central

    Franke, Andreas G.

    2012-01-01

    Pharmacological cognitive enhancement (CE) is a topic of increasing public awareness. In the scientific literature on student use of CE as a study aid for academic performance enhancement, there are high prevalence rates regarding the use of caffeinated substances (coffee, caffeinated drinks, caffeine tablets) but remarkably lower prevalence rates regarding the use of illicit/prescription stimulants such as amphetamines or methylphenidate. While the literature considers the reasons and mechanisms for these different prevalence rates from a theoretical standpoint, it lacks empirical data to account for healthy students who use both, caffeine and illicit/prescription stimulants, exclusively for the purpose of CE. Therefore, we extensively interviewed a sample of 18 healthy university students reporting non-medical use of caffeine as well as illicit/prescription stimulants for the purpose of CE in a face-to-face setting about their opinions regarding differences in general and morally-relevant differences between caffeine and stimulant use for CE. 44% of all participants answered that there is a general difference between the use of caffeine and illicit/prescription stimulants for CE, 28% did not differentiate, 28% could not decide. Furthermore, 39% stated that there is a moral difference, 56% answered that there is no moral difference and one participant was not able to comment on moral aspects. Participants came to their judgements by applying three dimensions: medical, ethical and legal. Weighing the medical, ethical and legal aspects corresponded to the students' individual preferences of substances used for CE. However, their views only partly depicted evidence-based medical aspects and the ethical issues involved. This result shows the need for well-directed and differentiated information to prevent the potentially harmful use of illicit or prescription stimulants for CE. PMID:22768218

  14. What users think about the differences between caffeine and illicit/prescription stimulants for cognitive enhancement.

    PubMed

    Franke, Andreas G; Lieb, Klaus; Hildt, Elisabeth

    2012-01-01

    Pharmacological cognitive enhancement (CE) is a topic of increasing public awareness. In the scientific literature on student use of CE as a study aid for academic performance enhancement, there are high prevalence rates regarding the use of caffeinated substances (coffee, caffeinated drinks, caffeine tablets) but remarkably lower prevalence rates regarding the use of illicit/prescription stimulants such as amphetamines or methylphenidate. While the literature considers the reasons and mechanisms for these different prevalence rates from a theoretical standpoint, it lacks empirical data to account for healthy students who use both, caffeine and illicit/prescription stimulants, exclusively for the purpose of CE. Therefore, we extensively interviewed a sample of 18 healthy university students reporting non-medical use of caffeine as well as illicit/prescription stimulants for the purpose of CE in a face-to-face setting about their opinions regarding differences in general and morally-relevant differences between caffeine and stimulant use for CE. 44% of all participants answered that there is a general difference between the use of caffeine and illicit/prescription stimulants for CE, 28% did not differentiate, 28% could not decide. Furthermore, 39% stated that there is a moral difference, 56% answered that there is no moral difference and one participant was not able to comment on moral aspects. Participants came to their judgements by applying three dimensions: medical, ethical and legal. Weighing the medical, ethical and legal aspects corresponded to the students' individual preferences of substances used for CE. However, their views only partly depicted evidence-based medical aspects and the ethical issues involved. This result shows the need for well-directed and differentiated information to prevent the potentially harmful use of illicit or prescription stimulants for CE.

  15. Action of caffeine on x-irradiated HeLa cells. VII. Evidence that caffeine enhances expression of potentially lethal radiation damage

    SciTech Connect

    Beetham, K.L.; Tolmach, L.J.

    1984-12-01

    HeLa cells irradiated with 2 Gy of 220-kV X rays suffer a 60-70% loss of colony-forming ability which is increased to 90% by postirradiation treatment with 10 mM caffeine for 6 hr. The detailed postirradiation patterns of cell death and sister-cell fusion in such cultures and in cultures in which the colony-forming ability was brought to about the same level by treatment with a larger (4 Gy) X-ray dose alone or by longer (48 hr) treatment with 10 mM caffeine alone were recorded by time-lapse cinemicrography. Because the patterns of cell death and fusion differ radically in irradiated and in caffeine-treated cultures, the response of the additional cells killed by the combined treatment can be identified as X-ray induced rather than caffeine induced. The appearance of cultures after several days of incubation confirms the similarity of the post-treatment patterns of proliferation in cultures suffering enhanced killing to those occurring in cultures treated with larger doses of X rays alone. It is concluded that x rays do not sensitize cells to caffeine, but rather that caffeine enhanced the expression of potentially lethal radiation-induced damage.

  16. Caffeine in floral nectar enhances a pollinator’s memory of reward

    PubMed Central

    Wright, G. A.; Baker, D. D.; Palmer, M. J.; Stabler, D.; Mustard, J. A.; Power, E. F.; Borland, A. M.; Stevenson, P. C.

    2015-01-01

    Plant defence compounds occur in floral nectar, but their ecological role is not well-understood. We provide the first evidence that plant compounds pharmacologically alter pollinator behaviour by enhancing their memory of reward. Honeybees rewarded with caffeine, which occurs naturally in nectar of Coffea and Citrus species, were three times more likely to remember a learned floral scent than those rewarded with sucrose alone. Caffeine potentiated responses of mushroom body neurons involved in olfactory learning and memory by acting as an adenosine receptor antagonist. Caffeine concentrations in nectar never exceeded the bees’ bitter taste threshold, implying that pollinators impose selection for nectar that is pharmacologically active but not repellent. By using a drug to enhance memories of reward, plants secure pollinator fidelity and improve reproductive success. PMID:23471406

  17. Removal of caffeine from green tea by microwave-enhanced vacuum ice water extraction.

    PubMed

    Lou, Zaixiang; Er, Chaojuan; Li, Jing; Wang, Hongxin; Zhu, Song; Sun, Juntao

    2012-02-24

    In order to selectively remove caffeine from green tea, a microwave-enhanced vacuum ice water extraction (MVIE) method was proposed. The effects of MVIE variables including extraction time, microwave power, and solvent to solid radio on the removal yield of caffeine and the loss of total phenolics (TP) from green tea were investigated. The optimized conditions were as follows: solvent (mL) to solid (g) ratio was 10:1, microwave extraction time was 6 min, microwave power was 350 W and 2.5 h of vacuum ice water extraction. The removal yield of caffeine by MVIE was 87.6%, which was significantly higher than that by hot water extraction, indicating a significant improvement of removal efficiency. Moreover, the loss of TP of green tea in the proposed method was much lower than that in the hot water extraction. After decaffeination by MVIE, the removal yield of TP tea was 36.2%, and the content of TP in green tea was still higher than 170 mg g(-1). Therefore, the proposed microwave-enhanced vacuum ice water extraction was selective, more efficient for the removal of caffeine. The main phenolic compounds of green tea were also determined, and the results indicated that the contents of several catechins were almost not changed in MVIE. This study suggests that MVIE is a new and good alternative for the removal of caffeine from green tea, with a great potential for industrial application. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. Ethanol enhances caffeine-induced Ca2+-release channel activation in skeletal muscle sarcoplasmic reticulum.

    PubMed

    Oba, T; Koshita, M; Yamaguchi, M

    1997-02-01

    When sarcoplasmic reticulum (SR) vesicles prepared from frog skeletal muscles were actively loaded with Ca2+, pretreatment of the SR with 2.2 mM (0.01%) ethanol for 30 s significantly potentiated 5 mM caffeine-induced release of Ca2+ from 16.7 +/- 3.7 nmol/mg protein in control without ethanol to 28.0 +/- 2.6 nmol/mg (P < 0.05, n = 5). Ethanol alone caused no release of Ca2+ from the SR. Exposure of the Ca2+-release channel, incorporated into planar lipid bilayers, to 2 mM caffeine significantly increased open probability (Po) and mean open time, but unitary conductance was not affected. Ethanol (2.2 mM) enhanced caffeine-induced Ca2+-release channel activity, with Po reaching 3.02-fold and mean open time 2.85-fold the values in the absence of ethanol. However, ethanol alone did not affect electrical parameters of single-channel current, over a concentration range of 2.2 mM (0.01%) to 217 mM (1%). The synergistic action of ethanol and caffeine on the channel activity could be attributable to enhancement of caffeine-induced release of Ca2+ from the SR vesicles in the presence of ethanol.

  19. Low dose of caffeine enhances the efficacy of antidepressants in major depressive disorder and the underlying neural substrates.

    PubMed

    Liu, Qing-Shan; Deng, Ran; Fan, Yuyan; Li, Keqin; Meng, Fangang; Li, Xueli; Liu, Rui

    2017-08-01

    Caffeine is one of the most frequently used psychoactive substances ingested mainly via beverage or food products. Major depressive disorder is a serious and devastating psychiatric disorder. Emerging evidence indicates that caffeine enhances the antidepressant-like activity of common antidepressant drugs in rodents. However, whether joint administration of low dose of caffeine enhances the antidepressant actions in depressed patients remains unclear. A total of 95 male inpatients were assigned to three groups and were asked to take either caffeine (60, 120 mg) or placebo (soymilk powder) daily for 4 wk on the basis of their current antidepressant medications. Results showed that chronic supplementation with low dose of caffeine (60 mg) produced rapid antidepressant action by reduction of depressive scores. Furthermore, low dose of caffeine improved cognitive performance in depressed patients. However, caffeine did not affect sleep as measured by overnight polysomnography. Moreover, chronic caffeine consumption elicited inhibition of hypothalamic-pituitary-adrenal axis activation by normalization of salivary cortisol induced by Trier social stress test. These findings indicated the potential benefits of further implications of supplementary administration of caffeine to reverse the development of depression and enhance the outcome of antidepressants treatment in major depressive disorder. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Caffeine-enhanced survival of radiation-sensitive, repair-deficient Chinese hamster cells

    SciTech Connect

    Utsumi, H.; Elkind, M.M.

    1983-11-01

    A clone of V79 Chinese hamster cells (V79-AL162/S-10) with unique properties has been isolated after a challenge of parental cells (V79-AL162) with 1 mM ouabain. Compared with parental cells, or with other clones isolated after the ouabain challenge, these cells form smaller colonies, are more sensitive to both x rays and fission-spectrum neutrons, and respond atypically to a postirradiation treatment with caffeine. Their enhanced response to x rays results mainly from a large reduction in the shoulder of their survival curve, probably because in late S phase, the most resistant phase in the cell cycle, the survival curve of these cells has a reduced shoulder width. Caffeine, and to a lesser extent theophylline, added to the colony-forming medium immediately after exposure appreciably increases the width of the shoulder of these sensitive cells, whereas caffeine has the opposite effect on the response of normal V79 cells. Thus the unique response of the V79-AL162/S-10 cells to a radiation posttreatment with caffeine (increased survival) results from a net increase in their ability to repair damage that is otherwise lethal; caffeine treatment ordinarly prevents normal V79 cells from repairing damage that is only potentially lethal.

  1. Enhancing physical performance in elite junior tennis players with a caffeinated energy drink.

    PubMed

    Gallo-Salazar, César; Areces, Francisco; Abián-Vicén, Javier; Lara, Beatriz; Salinero, Juan José; Gonzalez-Millán, Cristina; Portillo, Javier; Muñoz, Victor; Juarez, Daniel; Del Coso, Juan

    2015-04-01

    The aim of this study was to investigate the effectiveness of a caffeinated energy drink to enhance physical performance in elite junior tennis players. In 2 different sessions separated by 1 wk, 14 young (16 ± 1 y) elite-level tennis players ingested 3 mg caffeine per kg body mass in the form of an energy drink or the same drink without caffeine (placebo). After 60 min, participants performed a handgrip-strength test, a maximal-velocity serving test, and an 8 × 15-m sprint test and then played a simulated singles match (best of 3 sets). Instantaneous running speed during the matches was assessed using global positioning (GPS) devices. Furthermore, the matches were videotaped and notated afterward. In comparison with the placebo drink, the ingestion of the caffeinated energy drink increased handgrip force by ~4.2% ± 7.2% (P = .03) in both hands, the running pace at high intensity (46.7 ± 28.5 vs 63.3 ± 27.7 m/h, P = .02), and the number of sprints (12.1 ± 1.7 vs 13.2 ± 1.7, P = .05) during the simulated match. There was a tendency for increased maximal running velocity during the sprint test (22.3 ± 2.0 vs 22.9 ± 2.1 km/h, P = .07) and higher percentage of points won on service with the caffeinated energy drink (49.7% ± 9.8% vs 56.4% ± 10.0%, P = .07) in comparison with the placebo drink. The energy drink did not improve ball velocity during the serving test (42.6 ± 4.8 vs 42.7 ± 5.0 m/s, P = .49). The preexercise ingestion of caffeinated energy drinks was effective to enhance some aspects of physical performance of elite junior tennis players.

  2. Enhancing physical performance in male volleyball players with a caffeine-containing energy drink.

    PubMed

    Del Coso, Juan; Pérez-López, Alberto; Abian-Vicen, Javier; Salinero, Juan Jose; Lara, Beatriz; Valadés, David

    2014-11-01

    There are no scientific data about the effects of caffeine intake on volleyball performance. The aim of this study was to investigate the effect of a caffeine-containing energy drink to enhance physical performance in male volleyball players. A double-blind, placebo-controlled, randomized experimental design was used. In 2 different sessions separated by 1 wk, 15 college volleyball players ingested 3 mg of caffeine per kg of body mass in the form of an energy drink or the same drink without caffeine (placebo). After 60 min, participants performed volleyball-specific tests: standing spike test, maximal squat jump (SJ), maximal countermovement jump (CMJ), 15-s rebound jump test (15RJ), and agility T-test. Later, a simulated volleyball match was played and recorded. In comparison with the placebo drink, the ingestion of the caffeinated energy drink increased ball velocity in the spike test (73 ± 9 vs 75 ± 10 km/h, P < .05) and the mean jump height in SJ (31.1 ± 4.3 vs 32.7 ± 4.2 cm, P < .05), CMJ (35.9 ± 4.6 vs 37.7 ± 4.4 cm, P < .05), and 15RJ (29.0 ± 4.0 vs 30.5 ± 4.6 cm, P < .05). The time to complete the agility test was significantly reduced with the caffeinated energy drink (10.8 ± 0.7 vs 10.3 ± 0.4 s, P < .05). In addition, players performed successful volleyball actions more frequently (24.6% ± 14.3% vs 34.3% ± 16.5%, P < .05) with the ingestion of the caffeinated energy drink than with the placebo drink during the simulated game. A caffeine-containing energy drink, with a dose equivalent to 3 mg of caffeine per kg body mass, might be an effective ergogenic aid to improve physical performance and accuracy in male volleyball players.

  3. Mark.

    ERIC Educational Resources Information Center

    Lipman, Matthew; Smith, Theresa L., Ed.

    Mark is the central character in this story designed to help adolescents formulate a philosophy of values. The story is well suited for use in high school social studies courses and/or in philosophy or guidance units. Mark's thoughts and actions are reported as he interacts with his family, friends, acquaintances, and individuals of authority…

  4. Caffeine ingestion enhances perceptual responses during intermittent exercise in female team-game players.

    PubMed

    Ali, Ajmol; O'Donnell, Jemma; Von Hurst, Pamela; Foskett, Andrew; Holland, Sherina; Starck, Carlene; Rutherfurd-Markwick, Kay

    2016-01-01

    We examined the influence of caffeine supplementation on cognitive performance and perceptual responses in female team-game players taking low-dose monophasic oral contraceptives of the same hormonal composition. Ten females (24 ± 4 years; 59.7 ± 3.5 kg body mass; 2-6 training sessions per week) took part in a randomised, double-blind, placebo-controlled crossover-design trial. A 90-min intermittent treadmill-running protocol was completed 60 min following ingestion of a capsule containing either 6 mg • kg(-1) anhydrous caffeine or artificial sweetener (placebo). Perceptual responses (ratings of perceived exertion (RPE), feeling scale (FS), felt arousal scale (FAS)), mood (profile of mood states (POMS)) and cognitive performance (Stroop test, choice reaction time (CRT)) were completed before, during and after the exercise protocol, as well as after ~12 h post exercise. Caffeine ingestion significantly enhanced the ratings of pleasure (P = 0.008) and arousal (P = 0.002) during the exercise protocol, as well as increased vigour (POMS; P = 0.007), while there was a tendency for reduced fatigue (POMS; P = 0.068). Caffeine ingestion showed a tendency to decrease RPE (P = 0.068) and improve reaction times in the Stroop (P = 0.072) and CRT (P = 0.087) tests. Caffeine supplementation showed a positive effect on perceptual parameters by increasing vigour and a tendency to decrease fatigue during intermittent running activity in female games players taking low-dose monophasic oral contraceptive steroids (OCS).

  5. Acute caffeine ingestion enhances strength performance and reduces perceived exertion and muscle pain perception during resistance exercise.

    PubMed

    Duncan, Michael J; Stanley, Michelle; Parkhouse, Natalie; Cook, Kathryn; Smith, Mike

    2013-01-01

    The efficacy of caffeine ingestion in enhancing aerobic performance is well established. However, despite suggestions that caffeine may enhance resistance exercise performance, research is equivocal on the effect of acute caffeine ingestion on resistance exercise performance. It has also been suggested that dampened perception of perceived exertion and pain perception might be an explanation for any possible enhancement of resistance exercise performance due to caffeine ingestion. Therefore, the aim of this study was to examine the acute effect of caffeine ingestion on repetitions to failure, rating of perceived exertion (RPE) and muscle pain perception during resistance exercise to failure. Eleven resistance trained individuals (9 males, 2 females, mean age±SD=26.4±6.4 years), took part in this double-blind, randomised cross-over experimental study whereby they ingested a caffeinated (5 mg kg(-1)) or placebo solution 60 minutes before completing a bout of resistance exercise. Experimental conditions were separated by at least 48 hours. Resistance exercise sessions consisted of bench press, deadlift, prone row and back squat exercise to failure at an intensity of 60% 1 repetition maximum. Results indicated that participants completed significantly greater repetitions to failure, irrespective of exercise, in the presence of caffeine (p=0.0001). Mean±S.D of repetitions to failure was 19.6±3.7 and 18.5±4.1 in caffeine and placebo conditions, respectively. There were no differences in peak heart rate or peak blood lactate values across conditions (both p >0.05). RPE was significantly lower in the caffeine compared to the placebo condition (p=0.03) and was significantly higher during lower body exercises compared to upper body exercises irrespective of substance ingested (p=0.0001). For muscle pain perception, a significant condition by exercise interaction (p=0.027) revealed that muscle pain perception was lower in the caffeine condition, irrespective of exercise

  6. Alcohol tolerance in humans is enhanced by prior caffeine antagonism of alcohol-induced impairment.

    PubMed

    Fillmore, Mark T

    2003-02-01

    The author tested the hypothesis that a history of drug-induced antagonism of alcohol impairment would enhance alcohol tolerance in humans. Groups of participants (N = 21) repeatedly performed a psychomotor task under different drug treatments: 0.65 g/kg alcohol, 4 mg/kg caffeine, or both drugs combined. Tolerance to a 0.65 g/kg alcohol dose challenge was then tested. Results showed that a history of combined alcohol and caffeine administrations increased alcohol tolerance compared with an exposure history to either drug alone. The findings contribute to the understanding of the complexities of polydrug use history and provide a useful model to examine how alcohol tolerance might be affected by a history of coadministration with other drugs (e.g., cocaine and nicotine).

  7. Sleep Deprivation Impairs and Caffeine Enhances My Performance, but Not Always Our Performance.

    PubMed

    Faber, Nadira S; Häusser, Jan A; Kerr, Norbert L

    2017-02-01

    What effects do factors that impair or enhance performance in individuals have when these individuals act in groups? We provide a framework, called the GIE ("Effects of Grouping on Impairments and Enhancements") framework, for investigating this question. As prominent examples for individual-level impairments and enhancements, we discuss sleep deprivation and caffeine. Based on previous research, we derive hypotheses on how they influence performance in groups, specifically process gains and losses in motivation, individual capability, and coordination. We conclude that the effect an impairment or enhancement has on individual-level performance is not necessarily mirrored in group performance: grouping can help or hurt. We provide recommendations on how to estimate empirically the effects individual-level performance impairments and enhancements have in groups. By comparing sleep deprivation to stress and caffeine to pharmacological cognitive enhancement, we illustrate that we cannot readily generalize from group results on one impairment or enhancement to another, even if they have similar effects on individual-level performance.

  8. Caffeinated energy drinks--a growing problem.

    PubMed

    Reissig, Chad J; Strain, Eric C; Griffiths, Roland R

    2009-01-01

    Since the introduction of Red Bull in Austria in 1987 and in the United States in 1997, the energy drink market has grown exponentially. Hundreds of different brands are now marketed, with caffeine content ranging from a modest 50 mg to an alarming 505 mg per can or bottle. Regulation of energy drinks, including content labeling and health warnings differs across countries, with some of the most lax regulatory requirements in the U.S. The absence of regulatory oversight has resulted in aggressive marketing of energy drinks, targeted primarily toward young males, for psychoactive, performance-enhancing and stimulant drug effects. There are increasing reports of caffeine intoxication from energy drinks, and it seems likely that problems with caffeine dependence and withdrawal will also increase. In children and adolescents who are not habitual caffeine users, vulnerability to caffeine intoxication may be markedly increased due to an absence of pharmacological tolerance. Genetic factors may also contribute to an individual's vulnerability to caffeine-related disorders including caffeine intoxication, dependence, and withdrawal. The combined use of caffeine and alcohol is increasing sharply, and studies suggest that such combined use may increase the rate of alcohol-related injury. Several studies suggest that energy drinks may serve as a gateway to other forms of drug dependence. Regulatory implications concerning labeling and advertising, and the clinical implications for children and adolescents are discussed.

  9. Caffeinated Energy Drinks -- A Growing Problem

    PubMed Central

    Reissig, Chad J.; Strain, Eric C.; Griffiths, Roland R.

    2009-01-01

    Since the introduction of Red Bull in Austria in 1987 and in the United States in 1997, the energy drink market has grown exponentially. Hundreds of different brands are now marketed, with caffeine content ranging from a modest 50 mg to an alarming 505 mg per can or bottle. Regulation of energy drinks, including content labeling and health warnings differs across countries, with some of the most lax regulatory requirements in the U.S. The absence of regulatory oversight has resulted in aggressive marketing of energy drinks, targeted primarily toward young males, for psychoactive, performance-enhancing and stimulant drug effects. There are increasing reports of caffeine intoxication from energy drinks, and it seems likely that problems with caffeine dependence and withdrawal will also increase. In children and adolescents who are not habitual caffeine users, vulnerability to caffeine intoxication may be markedly increased due to an absence of pharmacological tolerance. Genetic factors may also contribute to an individual’s vulnerability to caffeine related disorders including caffeine intoxication, dependence, and withdrawal. The combined use of caffeine and alcohol is increasing sharply, and studies suggest that such combined use may increase the rate of alcohol-related injury. Several studies suggest that energy drinks may serve as a gateway to other forms of drug dependence. Regulatory implications concerning labeling and advertising, and the clinical implications for children and adolescents are discussed. PMID:18809264

  10. Sleep Deprivation Impairs and Caffeine Enhances My Performance, but Not Always Our Performance

    PubMed Central

    Faber, Nadira S.; Häusser, Jan A.; Kerr, Norbert L.

    2016-01-01

    What effects do factors that impair or enhance performance in individuals have when these individuals act in groups? We provide a framework, called the GIE ("Effects of Grouping on Impairments and Enhancements”) framework, for investigating this question. As prominent examples for individual-level impairments and enhancements, we discuss sleep deprivation and caffeine. Based on previous research, we derive hypotheses on how they influence performance in groups, specifically process gains and losses in motivation, individual capability, and coordination. We conclude that the effect an impairment or enhancement has on individual-level performance is not necessarily mirrored in group performance: grouping can help or hurt. We provide recommendations on how to estimate empirically the effects individual-level performance impairments and enhancements have in groups. By comparing sleep deprivation to stress and caffeine to pharmacological cognitive enhancement, we illustrate that we cannot readily generalize from group results on one impairment or enhancement to another, even if they have similar effects on individual-level performance. PMID:26468077

  11. Caffeine Use and Extroversion.

    ERIC Educational Resources Information Center

    Landrum, R. Eric; Meliska, Charles J.

    Some research on the stimulant effect of caffeine suggests that the amount of behavioral enhancement produced by caffeine may depend on subjects' prior experience with the task and the drug. A study was undertaken to test whether prior experience with a task while under the influence of caffeine would facilitate performance of that task. Male…

  12. Action of caffeine on x-irradiated HeLa cells. IV. Progression delays and enhanced cell killing at high caffeine concentrations

    SciTech Connect

    Tolmach, L.J.; Busse, P.M.

    1980-05-01

    The response of x-irradiated and unirradiated HeLa S3 cells to treatment with caffeine at concentrations between 1 and 10 nM has been examined with respect to both delay in progression through the cell generation cycle and enhancement of the expression of potentially lethal x-ray damage. Progression is delayed in a concentration-dependent fashion: the generation time is doubled at about 4 mM. The duration of G/sub 1/ is lengthened, and the rate of DNA synthesis is reduced, although the kinetics are different in the two phases; the rate of DNA synthesis is usually unaffected at 1 or 2 mM, while there is no concentration threshold for the slowing of progression through G/sub 1/. Progression through G/sub 2/ appears to be unaffected by concentrations up to at least 10 mM. Killing of irradiated cells in G/sub 2/ is somewhat greater after treatment with the higher caffeine concentrations than reported previously for 1 mM. Moreover, an additional mode of killing is observed in irradiated G/sub 1/ cells which had been found previously to be only slightly affected by 1 mM caffeine; they suffer extensive killing at concentrations above 5 mM. The time-survival curves for irradiated, caffeine-treated G/sub 1/ and G/sub 2/ cells have characteristically different shapes. The dose-survival curves for cells treated with the higher caffeine concentrations display steeper terminal slopes and narrower shoulders.

  13. Low-dose caffeine administered in chewing gum does not enhance cycling to exhaustion.

    PubMed

    Ryan, Edward J; Kim, Chul-Ho; Muller, Matthew D; Bellar, David M; Barkley, Jacob E; Bliss, Matthew V; Jankowski-Wilkinson, Andrea; Russell, Morgan; Otterstetter, Ronald; Macander, Daniela; Glickman, Ellen L; Kamimori, Gary H

    2012-03-01

    Low-dose caffeine administered in chewing gum does not enhance cycling to exhaustion. The purpose of the current investigation was to examine the effect of low-dose caffeine (CAF) administered in chewing gum at 3 different time points during submaximal cycling exercise to exhaustion. Eight college-aged (26 ± 4 years), physically active (45.5 ± 5.7 ml·kg(-1)·min(-1)) volunteers participated in 4 experimental trials. Two pieces of caffeinated chewing gum (100 mg per piece, total quantity of 200 mg) were administered in a double-blind manner at 1 of 3 time points (-35, -5, and +15 minutes) with placebo at the other 2 points and at all 3 points in the control trial. The participants cycled at 85% of maximal oxygen consumption until volitional fatigue and time to exhaustion (TTE) were recorded in minutes. Venous blood samples were obtained at -40, -10, and immediately postexercise and analyzed for serum-free fatty acid and plasma catecholamine concentrations. Oxygen consumption, respiratory exchange ratio, heart rate, glucose, lactate, ratings of perceived exertion, and perceived leg pain measures were obtained at baseline and every 10 minutes during cycling. The results showed that there were no significant differences between the trials for any of the parameters measured including TTE. These findings suggest that low-dose CAF administered in chewing gum has no effect on TTE during cycling in recreational athletes and is, therefore, not recommended.

  14. Effects of adolescent caffeine consumption on cocaine sensitivity.

    PubMed

    O'Neill, Casey E; Levis, Sophia C; Schreiner, Drew C; Amat, Jose; Maier, Steven F; Bachtell, Ryan K

    2015-03-01

    Caffeine is the most commonly used psychoactive substance, and consumption by adolescents has risen markedly in recent years. We identified the effects of adolescent caffeine consumption on cocaine sensitivity and determined neurobiological changes within the nucleus accumbens (NAc) that may underlie caffeine-induced hypersensitivity to cocaine. Male Sprague-Dawley rats consumed caffeine (0.3 g/l) or water for 28 days during adolescence (postnatal day 28-55; P28-P55) or adulthood (P67-P94). Testing occurred in the absence of caffeine during adulthood (P62-82 or P101-121). Cocaine-induced and quinpirole (D2 receptor agonist)-induced locomotion was enhanced in rats that consumed caffeine during adolescence. Adolescent consumption of caffeine also enhanced the development of a conditioned place preference at a sub-threshold dose of cocaine (7.5 mg/kg, i.p.). These behavioral changes were not observed in adults consuming caffeine for an equivalent period of time. Sucrose preferences were not altered in rats that consumed caffeine during adolescence, suggesting there are no differences in natural reward. Caffeine consumption during adolescence reduced basal dopamine levels and augmented dopamine release in the NAc in response to cocaine (5 mg/kg, i.p.). Caffeine consumption during adolescence also increased the expression of the dopamine D2 receptor, dopamine transporter, and adenosine A1 receptor and decreased adenosine A2A receptor expression in the NAc. Consumption of caffeine during adulthood increased adenosine A1 receptor expression in the NAc, but no other protein expression changes were observed. Together these findings suggest that caffeine consumption during adolescence produced changes in the NAc that are evident in adulthood and may contribute to increases in cocaine-mediated behaviors.

  15. Effects of Adolescent Caffeine Consumption on Cocaine Sensitivity

    PubMed Central

    O'Neill, Casey E; Levis, Sophia C; Schreiner, Drew C; Amat, Jose; Maier, Steven F; Bachtell, Ryan K

    2015-01-01

    Caffeine is the most commonly used psychoactive substance, and consumption by adolescents has risen markedly in recent years. We identified the effects of adolescent caffeine consumption on cocaine sensitivity and determined neurobiological changes within the nucleus accumbens (NAc) that may underlie caffeine-induced hypersensitivity to cocaine. Male Sprague-Dawley rats consumed caffeine (0.3 g/l) or water for 28 days during adolescence (postnatal day 28–55; P28–P55) or adulthood (P67–P94). Testing occurred in the absence of caffeine during adulthood (P62–82 or P101–121). Cocaine-induced and quinpirole (D2 receptor agonist)-induced locomotion was enhanced in rats that consumed caffeine during adolescence. Adolescent consumption of caffeine also enhanced the development of a conditioned place preference at a sub-threshold dose of cocaine (7.5 mg/kg, i.p.). These behavioral changes were not observed in adults consuming caffeine for an equivalent period of time. Sucrose preferences were not altered in rats that consumed caffeine during adolescence, suggesting there are no differences in natural reward. Caffeine consumption during adolescence reduced basal dopamine levels and augmented dopamine release in the NAc in response to cocaine (5 mg/kg, i.p.). Caffeine consumption during adolescence also increased the expression of the dopamine D2 receptor, dopamine transporter, and adenosine A1 receptor and decreased adenosine A2A receptor expression in the NAc. Consumption of caffeine during adulthood increased adenosine A1 receptor expression in the NAc, but no other protein expression changes were observed. Together these findings suggest that caffeine consumption during adolescence produced changes in the NAc that are evident in adulthood and may contribute to increases in cocaine-mediated behaviors. PMID:25328052

  16. Enhanced Brain Amyloid-β Clearance by Rifampicin and Caffeine as a Possible Protective Mechanism Against Alzheimer’s Disease

    PubMed Central

    Qosa, Hisham; Abuznait, Alaa H.; Hill, Ronald A.; Kaddoumi, Amal

    2014-01-01

    Rifampicin and caffeine are widely used drugs with reported protective effect against Alzheimer’s disease (AD). However, the mechanism underlying this effect is incompletely understood. In this study, we have hypothesized that enhanced amyloid-β (Aβ) clearance from the brain across the blood-brain barrier (BBB) of wild-type mice treated with rifampicin or caffeine is caused by both drugs potential to upregulate low-density lipoprotein receptor related protein-1 (LRP1) and/or P-glycoprotein (P-gp) at the BBB. Expression studies of LRP1 and P-gp in brain endothelial cells and isolated mice brain microvessels following treatment with rifampicin or caffeine demonstrated both drugs as P-gp inducers, and only rifampicin as an LRP1 inducer. Also, brain efflux index (BEI%) studies conducted on C57BL/6 mice treated with either drug to study alterations in Aβ clearance demonstrated the BEI% of Aβ in rifampicin (82.4 ± 4.3%) and caffeine (80.4 ± 4.8%) treated mice were significantly higher than those of control mice (62.4 ±6.1%, p <0.01). LRP1 and P-gp inhibition studies confirmed the importance of both proteins to the clearance of Aβ, and that enhanced clearance following drugs treatment was caused by LRP1 and/or P-gp upregulation at the mouse BBB. Furthermore, our results provided evidence for the presence of a yet to be identified transporter/receptor that plays significant role in Aβ clearance and is upregulated by caffeine and rifampicin. In conclusion, our results demonstrated the upregulation of LRP1 and P-gp at the BBB by rifampicin and caffeine enhanced brain Aβ clearance, and this effect could explain, at least in part, the protective effect of rifampicin and caffeine against AD. PMID:22504320

  17. Caffeine and exercise.

    PubMed

    Paluska, Scott A

    2003-08-01

    Caffeine is the most commonly consumed drug in the world, and athletes frequently use it as an ergogenic aid. It improves performance and endurance during prolonged, exhaustive exercise. To a lesser degree it also enhances short-term, high-intensity athletic performance. Caffeine improves concentration, reduces fatigue, and enhances alertness. Habitual intake does not diminish caffeine's ergogenic properties. Several mechanisms have been proposed to explain the physiologic effects of caffeine, but adenosine receptor antagonism most likely accounts for the primary mode of action. It is relatively safe and has no known negative performance effects, nor does it cause significant dehydration or electrolyte imbalance during exercise. Routine caffeine consumption may cause tolerance or dependence, and abrupt discontinuation produces irritability, mood shifts, headache, drowsiness, or fatigue. Major sport governing bodies ban excessive use of caffeine, but current monitoring techniques are inadequate, and ethical dilemmas persist regarding caffeine intake by athletes.

  18. Caffeinated coffee enhances co-operative behavior in the Mixed Motive Game in healthy volunteers.

    PubMed

    Tse, Wai S; Chan, Chi Choi S; Shiu, Shun Yan K; Chung, Pik Yee A; Cheng, Shuk Han

    2009-02-01

    Caffeinated drinks are commonly consumed in social gatherings. However, their effects on social behavior remain unclear. The present study examined the effects of caffeinated coffee on antidepressant-related co-operative behavior. Seventy-seven low-caffeine users took part in a randomized, double-blind, cross-over study of single dose of caffeinated coffee (150 mg caffeine) and decaffeinated coffee (9 mg caffeine) with at least a 3-day washout period. In each session, participants were asked to imagine a fictitious person and play the Mixed Motive Game with that person 45 min after coffee consumption. Heart rate, blood pressure, and state moods were measured at baseline and at 45 min post-coffee consumption. After caffeinated coffee, participants exhibited significantly higher blood pressure. They also allocated significantly fewer scores to themselves and sent significantly more sadness message during the game. These results suggest that caffeinated coffee may help to improve social support and depressive symptoms.

  19. Changes in caffeine states enhance return of fear in spider phobia.

    PubMed

    Mystkowski, Jayson L; Mineka, Susan; Vernon, Laura L; Zinbarg, Richard E

    2003-04-01

    Treatment of phobias is sometimes followed by a return of fear. Animal and human research has shown that changes in external and internal contexts between the time of treatment and follow-up tests often enhance return of fear. The present study examined whether shifts in caffeine (C) state would enhance return of fear. Participants who were highly afraid of spiders (n = 43) were treated in 1-session exposure-based therapy and tested for follow-up 1 week later. Participants were randomly assigned to 1 of 4 groups and received either placebo (P) or C at treatment and follow-up sessions: CC, PP, CP, and PC. Results demonstrated state-dependent learning. Participants experiencing incongruent drug states during treatment and follow-up (CP and PC) exhibited greater return of fear than those experiencing congruent drug states (CC and PP).

  20. Enhanced caffeine degradation by immobilised cells of Leifsonia sp. strain SIU.

    PubMed

    Ibrahim, Salihu; Shukor, Mohd Y; Syed, Mohd A; Johari, Wan L W; Shamaan, Nor A; Sabullah, Mohd K; Ahmad, Siti A

    2016-01-01

    In a previous study, we isolated Leifsonia sp. strain SIU, a new bacterium from agricultured soil. The bacterium was tested for its ability to degrade caffeine. The isolate was encapsulated in gellan gum and its ability to degrade caffeine was compared with the free cells. The optimal caffeine degradation was attained at a gellan gum concentration of 0.75% (w/v), a bead size of 4 mm diameter, and 250 beads per 100 mL of medium. At a caffeine concentration of 0.1 g/L, immobilised cells of the strain SIU degraded caffeine within 9 h, which is faster when compared to the case of free cells, in which it took 12 h to degrade. The immobilised cells degraded caffeine completely within 39 and 78 h at 0.5 and 1.0 g/L, while the free cells took 72 and 148 h at 0.5 and 1.0 g/L, respectively. At higher caffeine concentrations, immobilised cells exhibited a higher caffeine degradation rate. At concentrations of 1.5 and 2.0 g/L, caffeine-degrading activities of both immobilised and free cells were inhibited. The immobilised cells showed no loss in caffeine-degrading activity after being used repeatedly for nine 24-h cycles. The effect of heavy metals on immobilised cells was also tested. This study showed an increase in caffeine degradation efficiency when the cells were encapsulated in gellan gum.

  1. Investigation of the binding sites and orientation of caffeine on human serum albumin by surface-enhanced Raman scattering and molecular docking

    NASA Astrophysics Data System (ADS)

    Wang, Weinan; Zhang, Wei; Duan, Yaokai; Jiang, Yong; Zhang, Liangren; Zhao, Bing; Tu, Pengfei

    2013-11-01

    Fluorescence, normal Raman and surface-enhanced Raman scattering (SERS) were introduced to explore the absorptive geometry of caffeine on Human Serum Albumin (HSA) at physiological condition. The molecular docking was also employed to make a better understanding of the interaction between caffeine and HSA as well as to elucidate the detailed information of the major binding site. The results showed that caffeine could bind to HSA via the hydrophobic force of aromatic stacking and the main binding group on caffeine could be the pyrimidine ring. In addition, a consecutive set of changes in the orientation of caffeine molecule had been demonstrated during the process of caffeine binding to HSA, and the primary binding site was considered to be a hydrophobic cavity formed by Leu198, Lys199, Ser202, Phe211, Trp214, Val344, Ser454 and Leu481 in domain II.

  2. Caffeine enhances and accelerates the expression of sensitization induced by coca paste indicating its relevance as a main adulterant.

    PubMed

    Prieto, José P; Galvalisi, Martín; López-Hill, Ximena; Meikle, María N; Abin-Carriquiry, Juan A; Scorza, Cecilia

    2015-08-01

    Caffeine is an active adulterant found in several drugs of abuse including coca paste (CP). We had previously demonstrated that caffeine potentiated the acute stimulant effect induced by CP seized samples. The role of caffeine in the expression of sensitization elicited by a CP seized sample (CP1) was here evaluated. CP1 (equivalent dose of 10 mg/kg of cocaine), cocaine (pure, 10 mg/kg), a combination of cocaine 10 mg/kg plus caffeine 2.5 mg/kg (CP1-surrogate) and saline (control) were intraperitoneally injected in male rats under two different sensitization schedules. Ambulatory locomotion was recorded in 58 animals. After five daily CP1 injections and 5 days of withdrawal, CP1-challenged animals displayed a more robust sensitization than cocaine-treated animals. When a 3 injections-regime of CP1-surrogate or cocaine was assayed, only CP1-surrogate was able to elicit sensitization. Caffeine enhances and accelerates the CP1-induced sensitization. Results may shed light on the fast and high dependence observed in CP users. © American Academy of Addiction Psychiatry.

  3. Familial longevity is marked by enhanced insulin sensitivity.

    PubMed

    Wijsman, Carolien A; Rozing, Maarten P; Streefland, Trea C M; le Cessie, Saskia; Mooijaart, Simon P; Slagboom, P Eline; Westendorp, Rudi G J; Pijl, Hanno; van Heemst, Diana

    2011-02-01

    Insulin resistance is a risk factor for various age-related diseases. In the Leiden Longevity study, we recruited long-lived siblings and their offspring. Previously, we showed that, compared to controls, the offspring of long-lived siblings had a better glucose tolerance. Here, we compared groups of offspring from long-lived siblings and controls for the relation between insulin and glucose in nonfasted serum (n = 1848 subjects) and for quantitation of insulin action using a two-step hyperinsulinemic-euglycemic clamp (n = 24 subjects). Groups of offspring and controls were similar with regard to sex distribution, age, and body mass index. We observed a positive bi-phasic linear relationship between ln (insulin) levels and nonfasted glucose with a steeper slope from 10.7mU L(-1) insulin onwards in controls compared to offspring (P = 0.02). During the clamp study, higher glucose infusion rate was required to maintain euglycemia during high-dose insulin infusion (P = 0.036) in offspring, reflecting higher whole-body insulin sensitivity. After adjustment for sex, age, and fat mass, the insulin-mediated glucose disposal rate (GDR) was higher in offspring than controls (42.5 ± 2.7 vs. 33.2 ± 2.7 micromol kg(-1) min(-1) , mean ± SE, P = 0.025). The insulin-mediated suppression of endogenous glucose production and lipolysis did not differ between groups (all P > 0.05). Furthermore, GDR was significantly correlated with the mean age of death of the parents. In conclusion, offspring from long-lived siblings are marked by enhanced peripheral glucose disposal. Future research will focus on identifying the underlying biomolecular mechanisms, with the aim to promote health in old age.

  4. Caffeine and Performance.

    PubMed

    Yarnell, Angela M; Deuster, Patricia A

    The role of caffeine in enhancing performance has been studied for years, and there is no doubt that caffeine can be performance enhancing. Also, a wealth of information allows for an interesting distinction between physical and cognitive performance. Most adults in America consume moderate doses of caffeine in various forms on a daily basis as caffeine is typically found in coffee, tea, soft drinks, dietary supplements, energy drinks, energy shots, and chocolate, as well as over-the-counter pills and gums. Although caffeine is readily available and widely consumed, when using it to enhance performance, a few factors should be considered. The authors discuss caffeine use among Servicemembers, its properties and effects on physical and cognitive performance, how to use it to optimize performance, and, finally, some of safety and regulatory considerations. The bottom line is that all individuals do not respond the same way to caffeine and their response depends on how the body uses and breaks down caffeine. Thus, as a user, you should monitor your own responses and performance changes when using caffeine based on the general recommendations provided. 2016.

  5. 70 microM caffeine treatment enhances in vitro force and power output during cyclic activities in mouse extensor digitorum longus muscle.

    PubMed

    James, Rob S; Kohlsdorf, Tiana; Cox, Val M; Navas, Carlos A

    2005-09-01

    Caffeine ingestion by human athletes has been found to improve endurance performance primarily acting via the central nervous system as an adenosine receptor antagonist. However, a few studies have implied that the resultant micromolar levels of caffeine in blood plasma (70 microM maximum for humans) may directly affect skeletal muscle causing enhanced force production. In the present study, the effects of 70 microM caffeine on force and power output in isolated mouse extensor digitorum longus muscle were investigated in vitro at 35 degrees C. Muscle preparations were subjected to cyclical sinusoidal length changes with electrical stimulation conditions optimised to produce maximal work. 70 microM caffeine caused a small but significant increase (2-3%) in peak force and net work produced during work loops (where net work represents the work input required to lengthen the muscle subtracted from the work produced during shortening). However, these micromolar caffeine levels did not affect the overall pattern of fatigue or the pattern of recovery from fatigue. Our results suggest that the plasma concentrations found when caffeine is used to enhance athletic performance in human athletes might directly enhance force and power during brief but not prolonged activities. These findings potentially confirm previous in vivo studies, using humans, which implied caffeine ingestion may cause acute improvements in muscle force and power output but would not enhance endurance.

  6. Caffeine Enhances Real-World Language Processing: Evidence from a Proofreading Task

    ERIC Educational Resources Information Center

    Brunye, Tad T.; Mahoney, Caroline R.; Rapp, David N.; Ditman, Tali; Taylor, Holly A.

    2012-01-01

    Caffeine has become the most prevalently consumed psychostimulant in the world, but its influences on daily real-world functioning are relatively unknown. The present work investigated the effects of caffeine (0 mg, 100 mg, 200 mg, 400 mg) on a commonplace language task that required readers to identify and correct 4 error types in extended…

  7. Caffeine Enhances Real-World Language Processing: Evidence from a Proofreading Task

    ERIC Educational Resources Information Center

    Brunye, Tad T.; Mahoney, Caroline R.; Rapp, David N.; Ditman, Tali; Taylor, Holly A.

    2012-01-01

    Caffeine has become the most prevalently consumed psychostimulant in the world, but its influences on daily real-world functioning are relatively unknown. The present work investigated the effects of caffeine (0 mg, 100 mg, 200 mg, 400 mg) on a commonplace language task that required readers to identify and correct 4 error types in extended…

  8. Caffeine Enhances Memory Performance in Young Adults during Their Non-optimal Time of Day

    PubMed Central

    Sherman, Stephanie M.; Buckley, Timothy P.; Baena, Elsa; Ryan, Lee

    2016-01-01

    Many college students struggle to perform well on exams in the early morning. Although students drink caffeinated beverages to feel more awake, it is unclear whether these actually improve performance. After consuming coffee (caffeinated or decaffeinated), college-age adults completed implicit and explicit memory tasks in the early morning and late afternoon (Experiment 1). During the morning, participants ingesting caffeine demonstrated a striking improvement in explicit memory, but not implicit memory. Caffeine did not alter memory performance in the afternoon. In Experiment 2, participants engaged in cardiovascular exercise in order to examine whether increases in physiological arousal similarly improved memory. Despite clear increases in physiological arousal, exercise did not improve memory performance compared to a stretching control condition. These results suggest that caffeine has a specific benefit for memory during students’ non-optimal time of day – early morning. These findings have real-world implications for students taking morning exams. PMID:27895607

  9. Using Caffeine Pills for Performance Enhancement. An Experimental Study on University Students' Willingness and Their Intention to Try Neuroenhancements.

    PubMed

    Brand, Ralf; Koch, Helen

    2016-01-01

    Recent research has indicated that university students sometimes use caffeine pills for neuroenhancement (NE; non-medical use of psychoactive substances or technology to produce a subjective enhancement in psychological functioning and experience), especially during exam preparation. In our factorial survey experiment, we manipulated the evidence participants were given about the prevalence of NE amongst peers and measured the resulting effects on the psychological predictors included in the Prototype-Willingness Model of risk behavior. Two hundred and thirty-one university students were randomized to a high prevalence condition (read faked research results overstating usage of caffeine pills amongst peers by a factor of 5; 50%), low prevalence condition (half the estimated prevalence; 5%) or control condition (no information about peer prevalence). Structural equation modeling confirmed that our participants' willingness and intention to use caffeine pills in the next exam period could be explained by their past use of neuroenhancers, attitude to NE and subjective norm about use of caffeine pills whilst image of the typical user was a much less important factor. Provision of inaccurate information about prevalence reduced the predictive power of attitude with respect to willingness by 40-45%. This may be because receiving information about peer prevalence which does not fit with their perception of the social norm causes people to question their attitude. Prevalence information might exert a deterrent effect on NE via the attitude-willingness association. We argue that research into NE and deterrence of associated risk behaviors should be informed by psychological theory.

  10. Using Caffeine Pills for Performance Enhancement. An Experimental Study on University Students’ Willingness and Their Intention to Try Neuroenhancements

    PubMed Central

    Brand, Ralf; Koch, Helen

    2016-01-01

    Recent research has indicated that university students sometimes use caffeine pills for neuroenhancement (NE; non-medical use of psychoactive substances or technology to produce a subjective enhancement in psychological functioning and experience), especially during exam preparation. In our factorial survey experiment, we manipulated the evidence participants were given about the prevalence of NE amongst peers and measured the resulting effects on the psychological predictors included in the Prototype-Willingness Model of risk behavior. Two hundred and thirty-one university students were randomized to a high prevalence condition (read faked research results overstating usage of caffeine pills amongst peers by a factor of 5; 50%), low prevalence condition (half the estimated prevalence; 5%) or control condition (no information about peer prevalence). Structural equation modeling confirmed that our participants’ willingness and intention to use caffeine pills in the next exam period could be explained by their past use of neuroenhancers, attitude to NE and subjective norm about use of caffeine pills whilst image of the typical user was a much less important factor. Provision of inaccurate information about prevalence reduced the predictive power of attitude with respect to willingness by 40-45%. This may be because receiving information about peer prevalence which does not fit with their perception of the social norm causes people to question their attitude. Prevalence information might exert a deterrent effect on NE via the attitude-willingness association. We argue that research into NE and deterrence of associated risk behaviors should be informed by psychological theory. PMID:26903909

  11. Enhanced mood and psychomotor performance by a caffeine-containing energy capsule in fatigued individuals.

    PubMed

    Childs, Emma; de Wit, Harriet

    2008-02-01

    Caffeine produces mild psychostimulant effects that may be particularly evident in individuals whose mood or performance is impaired by sleep restriction or caffeine withdrawal. Caffeinated energy drinks have been shown to improve energy and cognition but expectancy effects cannot be ruled out in these studies. Very few studies have examined the effects of caffeine-containing energy capsules upon behavioral and subjective measures. This study compared the effects of a caffeine-containing (200 mg) supplement (CAF) or placebo in capsule form after prolonged wakefulness, in participants who varied in their level of habitual caffeine use. Thirty-five healthy volunteers (16 male, 19 female) participated in two experimental sessions in which they remained awake between 5 p.m. and 5 a.m. At 3:30 a.m. they consumed CAF or placebo in random order under double-blind conditions. Participants completed subjective effects questionnaires and performed computerized attention tasks before and after consuming capsules. Heart rate and blood pressure were monitored at regular intervals. Compared to measures at 5 p.m., participants reported more tiredness and mood disturbance at 3 a.m., and exhibited longer reaction times and more attentional lapses. Heavier caffeine consumers exhibited the greatest decreases in Profile of Mood States (POMS) Vigor. CAF produced stimulant-like effects and significantly improved mood and reaction times upon the tasks. These effects did not vary with level of habitual caffeine consumption. These findings indicate that consumption of a caffeine-containing food supplement improves subjective state and cognitive performance in fatigued individuals that is likely a result of its caffeine content. 2008 APA

  12. Enhancing the IMS QTI to Better Support Computer Assisted Marking

    ERIC Educational Resources Information Center

    Clark, Damien; Baillie-de Byl, Penny

    2007-01-01

    Computer aided assessment is a common approach used by educational institutions. The benefits range into the design of teaching, learning, and instructional materials. While some such systems implement fully automated marking for multiple choice questions and fill-in-the-blanks, they are insufficient when human critiquing is required. Current…

  13. Coteratogenic effects of caffeine.

    PubMed

    Sivak, A

    1994-02-01

    Coteratogenicity studies have been carried out using various physical and chemical agents along with caffeine. For ionizing radiation in mice, enhancement of teratogenic responses (cleft palate, limb malformations) was noted with single systemic bolus doses of 50 to 200 mg/kg. Studies in rats with ethanol or nicotine reveal only an additive effect with caffeine. There are mixed results with chemical carcinogens and caffeine with some studies showing enhancement and others showing that caffeine inhibits the teratogenic effect of some carcinogens. The time of treatment, at the time of carcinogen exposure for the inhibition and later in the gestation period for the enhancement, appears to be the critical factor. For a variety of pharmaceutical agents (acetazolamide, mitomycin C, hydroxyurea, 5-fluorouracil), caffeine was shown to enhance the teratogenic effect of the agent. With 5-azacytidine in rats, caffeine suppressed limb malformations. Administration of inhibitors of beta-adrenergic function reduces the teratogenic effect of caffeine in mice. The interpretation of the experimental studies in terms of human hazard is complicated by the general use of high-dose bolus exposures which are not typical of human exposures, and the use of test systems that are not readily applicable to humans. The studies in human populations show clearly that caffeine itself has no link to negative birth outcome, and in the few instances where it has been examined there appears to be no interaction between coffee consumption and either alcohol consumption or smoking on pregnancy outcome.

  14. Caffeine ingestion acutely enhances muscular strength and power but not muscular endurance in resistance-trained men.

    PubMed

    Grgic, Jozo; Mikulic, Pavle

    2017-09-01

    The goal of this randomized, double-blind, cross-over study was to assess the acute effects of caffeine ingestion on muscular strength and power, muscular endurance, rate of perceived exertion (RPE), and pain perception (PP) in resistance-trained men. Seventeen volunteers (mean ± SD: age = 26 ± 6 years, stature = 182 ± 9 cm, body mass = 84 ± 9 kg, resistance training experience = 7 ± 3 years) consumed placebo or 6 mg kg(-1) of anhydrous caffeine 1 h before testing. Muscular power was assessed with seated medicine ball throw and vertical jump exercises, muscular strength with one-repetition maximum (1RM) barbell back squat and bench press exercises, and muscular endurance with repetitions of back squat and bench press exercises (load corresponding to 60% of 1RM) to momentary muscular failure. RPE and PP were assessed immediately after the completion of the back squat and bench press exercises. Compared to placebo, caffeine intake enhanced 1RM back squat performance (+2.8%; effect size [ES] = 0.19; p = .016), which was accompanied by a reduced RPE (+7%; ES = 0.53; p = .037), and seated medicine ball throw performance (+4.3%, ES = 0.32; p = .009). Improvements in 1RM bench press were not noted although there were significant (p = .029) decreases in PP related to this exercise when participants ingested caffeine. The results point to an acute benefit of caffeine intake in enhancing lower-body strength, likely due to a decrease in RPE; upper-, but not lower-body power; and no effects on muscular endurance, in resistance-trained men. Individuals competing in events in which strength and power are important performance-related factors may consider taking 6 mg kg(-1) of caffeine pre-training/competition for performance enhancement.

  15. Caffeine expectancies influence the subjective and behavioral effects of caffeine.

    PubMed

    Harrell, Paul T; Juliano, Laura M

    2009-12-01

    This study investigated the independent and interactive effects of caffeine pharmacology and expected effects of caffeine on performance and subjective outcomes. Abstinent coffee drinkers (n = 60) consumed decaffeinated coffee with either 280 mg or 0 mg added caffeine. Caffeine dose was crossed with varying instructions that the coffee would either enhance or impair performance in a 2 x 2 factorial design. Performance, mood, caffeine withdrawal, and negative somatic effects were assessed. Relative to placebo, caffeine improved reaction time and accuracy on the rapid visual information processing task, a measure of vigilance. However, there was a significant dose by expectancy interaction that revealed that among participants given placebo coffee, "impair" instructions produced better performance than "enhance" instructions. Caffeine also improved psychomotor performance as indicated by a finger tapping task with no main effects of expectancy or interactions. Impair instructions produced greater reports of negative somatic effects than enhance instructions, but only when caffeine was administered. Manipulating the expected effects of caffeine altered the behavioral and subjective effects of caffeine. A significant dose by expectancy interaction revealed a somewhat paradoxical outcome in the placebo conditions whereby those told "impair" performed better than those told "enhance." This may reflect compensatory responding as has been observed in similar studies using alcohol (Fillmore et al. Psychopharmacology 115:383-388, 1994). Impair instructions led to greater negative somatic effects only when caffeine was administered supporting the active placebo hypothesis.

  16. Trait-anger enhances effects of caffeine on psychomotor vigilance performance.

    PubMed

    Killgore, William D S; Killgore, Desiree B; Ganesan, Goutham; Krugler, Alexandra L; Kamimori, Gary H

    2006-12-01

    This study examined the combined effects of caffeine and the personality attribute of trait-anger on the speed of psychomotor vigilance performance during sleep deprivation. 23 young adult soldiers (19 male) were administered the State-Trait Anger Expression Inventory-2 when well-rested. Participants were then sleep deprived for three consecutive nights (77 hours total) during which they completed repeated psychomotor vigilance testing. Half of the participants received four doses of oral caffeine (200 mg every 2 hr.; 800 mg total) each night, while the other half were administered a placebo. For the first night, higher scores on trait-anger, outward anger expression, and intensity of anger expression predicted better sustained overnight vigilance performance, but only for those volunteers receiving caffeine. These correlations were not significant for the subsequent nights. Findings suggest a possible synergistic effect between personality traits associated with arousal of the central nervous system and vigilance-promoting effects of caffeine.

  17. Cognitive Performance Enhancement Induced by Caffeine, Carbohydrate and Guarana Mouth Rinsing during Submaximal Exercise

    PubMed Central

    Pomportes, Laura; Brisswalter, Jeanick; Casini, Laurence; Hays, Arnaud; Davranche, Karen

    2017-01-01

    The aim of this study was to investigate the influence of serial mouth rinsing (MR) with nutritional supplements on cognitive performance (i.e., cognitive control and time perception) during a 40-min submaximal exercise. Twenty-four participants completed 4 counterbalanced experimental sessions, during which they performed MR with either placebo (PL), carbohydrate (CHO: 1.6 g/25 mL), guarana complex (GUAc: 0.4 g/25 mL) or caffeine (CAF: 67 mg/25 mL) before and twice during exercise. The present study provided some important new insights regarding the specific changes in cognitive performance induced by nutritional supplements. The main results were: (1) CHO, CAF and GUA MR likely led participants to improve temporal performance; (2) CAF MR likely improved cognitive control; and (3) CHO MR led to a likely decrease in subjective perception of effort at the end of the exercise compared to PL, GUA and CAF. Moreover, results have shown that performing 40-min submaximal exercise enhances information processing in terms of both speed and accuracy, improves temporal performance and does not alter cognitive control. The present study opens up new perspectives regarding the use of MR to optimize cognitive performance during physical exercise. PMID:28598402

  18. Cognitive Performance Enhancement Induced by Caffeine, Carbohydrate and Guarana Mouth Rinsing during Submaximal Exercise.

    PubMed

    Pomportes, Laura; Brisswalter, Jeanick; Casini, Laurence; Hays, Arnaud; Davranche, Karen

    2017-06-09

    The aim of this study was to investigate the influence of serial mouth rinsing (MR) with nutritional supplements on cognitive performance (i.e., cognitive control and time perception) during a 40-min submaximal exercise. Twenty-four participants completed 4 counterbalanced experimental sessions, during which they performed MR with either placebo (PL), carbohydrate (CHO: 1.6 g/25 mL), guarana complex (GUAc: 0.4 g/25 mL) or caffeine (CAF: 67 mg/25 mL) before and twice during exercise. The present study provided some important new insights regarding the specific changes in cognitive performance induced by nutritional supplements. The main results were: (1) CHO, CAF and GUA MR likely led participants to improve temporal performance; (2) CAF MR likely improved cognitive control; and (3) CHO MR led to a likely decrease in subjective perception of effort at the end of the exercise compared to PL, GUA and CAF. Moreover, results have shown that performing 40-min submaximal exercise enhances information processing in terms of both speed and accuracy, improves temporal performance and does not alter cognitive control. The present study opens up new perspectives regarding the use of MR to optimize cognitive performance during physical exercise.

  19. A Combination of Amino Acids and Caffeine Enhances Sprint Running Capacity in a Hot, Hypoxic Environment.

    PubMed

    Eaton, Tom R; Potter, Aaron; Billaut, François; Panchuk, Derek; Pyne, David B; Gore, Christopher J; Chen, Ting-Ting; McQuade, Leon; Stepto, Nigel K

    2016-02-01

    Heat and hypoxia exacerbate central nervous system (CNS) fatigue. We therefore investigated whether essential amino acid (EAA) and caffeine ingestion attenuates CNS fatigue in a simulated team sport-specific running protocol in a hot, hypoxic environment. Subelite male team sport athletes (n = 8) performed a repeat sprint running protocol on a nonmotorized treadmill in an extreme environment on 4 separate occasions. Participants ingested one of four supplements: a double placebo, 3 mg.kg-1 body mass of caffeine + placebo, 2 x 7 g EAA (Musashi Create)+placebo, or caffeine + EAA before each exercise session using a randomized, double-blind crossover design. Electromyography (EMG) activity and quadriceps evoked responses to magnetic stimulation were assessed from the dominant leg at preexercise, halftime, and postexercise. Central activation ratio (CAR) was used to quantify completeness of quadriceps activation. Oxygenation of the prefrontal cortex was measured via near-infrared spectroscopy. Mean sprint work was higher (M = 174 J, 95% CI [23, 324], p < .05, d = 0.30; effect size, likely beneficial) in the caffeine + EAA condition versus EAAs alone. The decline in EMG activity was less (M = 13%, 95% CI [0, 26]; p < .01, d = 0.58, likely beneficial) in caffeine + EAA versus EAA alone. Similarly, the pre- to postexercise decrement in CAR was significantly less (M = -2.7%, 95% CI [0.4, 5.4]; p < .05, d = 0.50, likely beneficial) when caffeine + EAA were ingested compared with placebo. Cerebral oxygenation was lower (M = -5.6%, 95% CI [1.0, 10.1]; p < .01, d = 0.60, very likely beneficial) in the caffeine + EAA condition compared with LNAA alone. Co-ingestion of caffeine and EAA appears to maintain muscle activation and central drive, with a small improvement in running performance.

  20. Marked point processes for enhancing seismic fault patterns

    NASA Astrophysics Data System (ADS)

    Barna, Keresztes; Szirányi, Tamás; Borda, Monica; Lavialle, Olivier

    2015-07-01

    In this paper we present a new method for fault extraction in seismic blocks, using marked point processes. Our goal is to increase the detection accuracy of the state of the art fault attributes by computing them on a system of objects based on an a priori knowledge about the faults. An original curved support has been developed to describe the faults in vertical sections of the seismic blocks. The results are compared with the previous models used for linear network extraction, such as the Candy model. Synthetic blocks were used to compare the results obtained thanks to the point processes with the classical attributes. To segment the whole blocks, a multi-2D approach was used. Several modifications of the algorithm were necessary in order to make the results easier to interpret for geologists. One interest of the high-level approach offered by the marked point processes is the possibility of using the objects as a common support for various fault detection operators. A whole detection framework can be proposed which acts like a decision fusion process.

  1. Enhancement of caffeine-induced locomotor hyperactivity produced by the combination with L-arginine or taurine in mice: Possible involvement of nitric oxide.

    PubMed

    Kimura, M; Ushijima, I; Hiraki, M; Kimura, M; Ono, Nobufumi

    2009-11-01

    Combinations of caffeine with L-arginine or with taurine can enhance the effect of caffeine, but the mechanisms remain elusive. This study was designed to test the hypothesis that stimulant effects of central nervous system nitric oxide (NO) may explain the beneficial effect of caffeine on combinations with amino acid, L-arginine or taurine. Caffeine increased the spontaneous locomotor activity dose-dependently (2-10 mg/kg) in mice. The locomotor activity induced by caffeine at a dose of 2 mg/kg was enhanced by combined administration of L-arginine at a dose of 600 mg/kg, or taurine at a dose of 400 mg/kg, respectively. For both combinations, enhancement was significantly inhibited by pretreatment with N-nitro-L-arginine methyl ester (L-NAME) at a dose of 40 mg/kg. These results suggest that the enhancement induced by combining caffeine with amino acid might be regulated at least in part by NO in the central nervous system. Copyright 2009 Prous Science, S.A.U. or its licensors. All rights reserved.

  2. Acute consumption of a caffeinated energy drink enhances aspects of performance in sprint swimmers.

    PubMed

    Lara, Beatriz; Ruiz-Vicente, Diana; Areces, Francisco; Abián-Vicén, Javier; Salinero, Juan José; Gonzalez-Millán, Cristina; Gallo-Salazar, César; Del Coso, Juan

    2015-09-28

    This study investigated the effect of a caffeinated energy drink on various aspects of performance in sprint swimmers. In a randomised and counterbalanced order, fourteen male sprint swimmers performed two acute experimental trials after the ingestion of a caffeinated energy drink (3 mg/kg) or after the ingestion of the same energy drink without caffeine (0 mg/kg; placebo). After 60 min of ingestion of the beverages, the swimmers performed a countermovement jump, a maximal handgrip test, a 50 m simulated competition and a 45 s swim at maximal intensity in a swim ergometer. A blood sample was withdrawn 1 min after the completion of the ergometer test. In comparison with the placebo drink, the intake of the caffeinated energy drink increased the height in the countermovement jump (49.4 (SD 5.3) v. 50.9 (SD 5.2) cm, respectively; P<0.05) and maximal force during the handgrip test with the right hand (481 (SD 49) v. 498 (SD 43) N; P<0.05). Furthermore, the caffeinated energy drink reduced the time needed to complete the 50 m simulated swimming competition (27.8 (SD 3.4) v. 27.5 (SD 3.2) s; P<0.05), and it increased peak power (273 (SD 55) v. 303 (SD 49) W; P <0.05) and blood lactate concentration (11.0 (SD 2.0) v. 11.7 (SD 2.1) mM; P<0.05) during the ergometer test. The caffeinated energy drink did not modify the prevalence of insomnia (7 v. 7%), muscle pain (36 v. 36%) or headache (0 v. 7%) during the hours following its ingestion (P>0.05). A caffeinated energy drink increased some aspects of swimming performance in competitive sprinters, whereas the side effects derived from the intake of this beverage were marginal at this dosage.

  3. Caffeine and adenosine.

    PubMed

    Ribeiro, Joaquim A; Sebastião, Ana M

    2010-01-01

    Caffeine causes most of its biological effects via antagonizing all types of adenosine receptors (ARs): A1, A2A, A3, and A2B and, as does adenosine, exerts effects on neurons and glial cells of all brain areas. In consequence, caffeine, when acting as an AR antagonist, is doing the opposite of activation of adenosine receptors due to removal of endogenous adenosinergic tonus. Besides AR antagonism, xanthines, including caffeine, have other biological actions: they inhibit phosphodiesterases (PDEs) (e.g., PDE1, PDE4, PDE5), promote calcium release from intracellular stores, and interfere with GABA-A receptors. Caffeine, through antagonism of ARs, affects brain functions such as sleep, cognition, learning, and memory, and modifies brain dysfunctions and diseases: Alzheimer's disease, Parkinson's disease, Huntington's disease, Epilepsy, Pain/Migraine, Depression, Schizophrenia. In conclusion, targeting approaches that involve ARs will enhance the possibilities to correct brain dysfunctions, via the universally consumed substance that is caffeine.

  4. Contrast enhancement of bite mark images using the grayscale mixer in ACR in Photoshop®.

    PubMed

    Evans, Sam; Noorbhai, Suzanne; Lawson, Zoe; Stacey-Jones, Seren; Carabott, Romina

    2013-05-01

    Enhanced images may improve bite mark edge definition, assisting forensic analysis. Current contrast enhancement involves color extraction, viewing layered images by channel. A novel technique, producing a single enhanced image using the grayscale mix panel within Adobe Camera Raw®, has been developed and assessed here, allowing adjustments of multiple color channels simultaneously. Stage 1 measured RGB values in 72 versions of a color chart image; eight sliders in Photoshop® were adjusted at 25% intervals, all corresponding colors affected. Stage 2 used a bite mark image, and found only red, orange, and yellow sliders had discernable effects. Stage 3 assessed modality preference between color, grayscale, and enhanced images; on average, the 22 survey participants chose the enhanced image as better defined for nine out of 10 bite marks. The study has shown potential benefits for this new technique. However, further research is needed before use in the analysis of bite marks.

  5. Caffeine overdose

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/002579.htm Caffeine overdose To use the sharing features on this page, please enable JavaScript. Caffeine is a substance that exists naturally in certain ...

  6. Caffeine and cognitive performance: persistent methodological challenges in caffeine research.

    PubMed

    James, Jack E

    2014-09-01

    Human cognitive performance is widely perceived to be enhanced by caffeine at usual dietary doses. However, the evidence for and against this belief continues to be vigorously contested. Controversy has centred on caffeine withdrawal and withdrawal reversal as potential sources of experimental confounding. In response, some researchers have enlisted "caffeine-naïve" experimental participants (persons alleged to consume little or no caffeine) assuming that they are not subject to withdrawal. This mini-review examines relevant research to illustrate general methodological challenges that have been the cause of enduring confusion in caffeine research. At issue are the processes of caffeine withdrawal and withdrawal reversal, the definition of caffeine-naïve, the population representativeness of participants deemed to be caffeine-naïve, and confounding due to caffeine tolerance. Attention to these processes is necessary if premature conclusions are to be avoided, and if caffeine's complex effects and the mechanisms responsible for those effects are to be illuminated. Strategies are described for future caffeine research aimed at minimising confounding from withdrawal and withdrawal reversal.

  7. Caffeine analogs: biomedical impact.

    PubMed

    Daly, J W

    2007-08-01

    Caffeine, widely consumed in beverages, and many xanthine analogs have had a major impact on biomedical research. Caffeine and various analogs, the latter designed to enhance potency and selectivity toward specific biological targets, have played key roles in defining the nature and role of adenosine receptors, phosphodiesterases, and calcium release channels in physiological processes. Such xanthines and other caffeine-inspired heterocycles now provide important research tools and potential therapeutic agents for intervention in Alzheimer's disease, asthma, cancer, diabetes, and Parkinson's disease. Such compounds also have activity as analgesics, antiinflammatories, antitussives, behavioral stimulants, diuretics/natriuretics, and lipolytics. Adverse effects can include anxiety, hypertension, certain drug interactions, and withdrawal symptoms.

  8. Enhancement of High-Intensity Actions and Physical Performance During a Simulated Brazilian Jiu-Jitsu Competition With a Moderate Dose of Caffeine.

    PubMed

    Diaz-Lara, Francisco Javier; Del Coso, Juan; Portillo, Javier; Areces, Francisco; García, Jose Manuel; Abián-Vicén, Javier

    2016-10-01

    Although caffeine is one of the most commonly used substances in combat sports, information about its ergogenic effects on these disciplines is very limited. To determine the effectiveness of ingesting a moderate dose of caffeine to enhance overall performance during a simulated Brazilian jiu-jitsu (BJJ) competition. Fourteen elite BJJ athletes participated in a double-blind, placebo-controlled experimental design. In a random order, the athletes ingested either 3 mg/kg body mass of caffeine or a placebo (cellulose, 0 mg/kg) and performed 2 simulated BJJ combats (with 20 min rest between them), following official BJJ rules. Specific physical tests such as maximal handgrip dynamometry, maximal height during a countermovement jump, permanence during a maximal static-lift test, peak power in a bench-press exercise, and blood lactate concentration were measured at 3 specific times: before the first combat and immediately after the first and second combats. The combats were video-recorded to analyze fight actions. After the caffeine ingestion, participants spent more time in offensive actions in both combats and revealed higher blood lactate values (P < .05). Performance in all physical tests carried out before the first combat was enhanced with caffeine (P < .05), and some improvements remained after the first combat (eg, maximal static-lift test and bench-press exercise; P < .05). After the second combat, the values in all physical tests were similar between caffeine and placebo. Caffeine might be an effective ergogenic aid for improving intensity and physical performance during successive elite BJJ combats.

  9. Caffeine enhances cognitive function and skill performance during simulated soccer activity.

    PubMed

    Foskett, Andrew; Ali, Ajmol; Gant, Nicholas

    2009-08-01

    There is little evidence regarding the benefits of caffeine ingestion on cognitive function and skillful actions during sporting performance, especially in sports that are multifaceted in their physiological, skill, and cognitive demands. To examine the influence of caffeine on performance during simulated soccer activity. Twelve male soccer players completed two 90-min soccer-specific intermittent running trials interspersed with tests of soccer skill (LSPT). The trials were separated by 7 days and adhered to a randomized crossover design. On each occasion participants ingested 6 mg/kg body mass (BM) of caffeine (CAF) or a placebo (PLA) in a double-blind fashion 60 min before exercise. Movement time, penalties accrued, and total time were recorded for the LSPT. Physiological and performance markers were measured throughout the protocol. Water (3 ml/kg BM) was ingested every 15 min. Participants accrued significantly less penalty time in the CAF trial (9.7 +/- 6.6 s vs. PLA 11.6 +/- 7.4 s; p = .02), leading to a significantly lower total time in this trial (CAF 51.6 +/- 7.7 s vs. PLA 53.9 +/- 8.5 s; p = .02). This decrease in penalty time was probably attributable to an increased passing accuracy in the CAF trial (p = .06). Jump height was 2.7% (+/- 1.1%) higher in the CAF trial (57.1 +/- 5.1 cm vs. PLA 55.6 +/- 5.1 cm; p = .01). Caffeine ingestion before simulated soccer activity improved players' passing accuracy and jump performance without any detrimental effects on other performance parameters.

  10. Development and Characterization of Polyphenon 60 and Caffeine Microemulsion for Enhanced Antibacterial Activity

    PubMed Central

    Gupta, Sonal; Bansal, Rakhi; Ali, Javed; Gabrani, Reema; Dang, Shweta

    2014-01-01

    Green tea catechins and caffeine have exhibited antibacterial activity; however, their use is limited by lack of stability and effective delivery systems. Polyphenon 60 (P60) and caffeine were encapsulated in a single microemulsion (ME) formulation with an objective to lower the minimum inhibitory concentrations (MICs) of the individual agents against selected pathogens (S. epidermidis and E. coli). Combination of two natural compounds would advocate two different mechanisms on the bacterial growth thereby providing for better antibacterial activity. Thermodynamically stable ME was developed and characterized with an average particle size of 17.58 nm, further confirmed by TEM analysis. Antibacterial studies included chequerboard microdilution assay to determine the MIC and fractional inhibitory concentration (FIC) of both the natural compounds individually and in combination. MIC and FIC results indicated that the combination of the above two natural compounds was proficient in lowering the MICs of individual agents. Results of DPPH assay indicated that ME system preserved the long term antioxidative potential of P60 and caffeine. The cytotoxicity of the optimized formulation on Vero cell line by MTT assay was found to be nontoxic to mammalian cells. PMID:25050379

  11. Caffeine enhanced measurement of mutagenesis by low levels of [gamma]-irradiation in human lymphocytes

    SciTech Connect

    Puck, T.P.; Johnson, R.; Waldren, C.A. ); Morse, H. )

    1993-09-01

    The well-known action of caffeine in synergizing mutagenesis (including chromosome aberrations) of agents like ionizing radiation by inhibition of cellular repair processes has been incorporated into a rapid procedure for detection of mutagenicity with high sensitivity. Effects of 5-10 rads of [gamma]-irradiation, which approximate the human lifetime dose accumulation from background radiation, can be detected in a two-day procedure using an immortalized human WBC culture. Chromosomally visible lesions are scored on cells incubated for 2 h after irradiation in the presence and absence of 1.0 mg/ml of caffeine. An eightfold amplification of scorable lesions is achieved over the action of radiation alone. This approach provides a closer approximation to absolute mutagenicity unmitigated by repair processes, which can vary in different situations. It is proposed that mutagenesis testing of this kind, using caffiene or other repair-inhibitory agents, be employed to identify mutagens in their effective concentrations to which human populations may be exposed; to detect agents such as caffeine that may synergize mutagenic actions and pose epidemiologic threats; and to discover effective anti-mutagens. Information derived from the use of such procedures may help prevent cancer and newly acquired genetic disease.

  12. Development and characterization of polyphenon 60 and caffeine microemulsion for enhanced antibacterial activity.

    PubMed

    Gupta, Sonal; Bansal, Rakhi; Ali, Javed; Gabrani, Reema; Dang, Shweta

    2014-01-01

    Green tea catechins and caffeine have exhibited antibacterial activity; however, their use is limited by lack of stability and effective delivery systems. Polyphenon 60 (P60) and caffeine were encapsulated in a single microemulsion (ME) formulation with an objective to lower the minimum inhibitory concentrations (MICs) of the individual agents against selected pathogens (S. epidermidis and E. coli). Combination of two natural compounds would advocate two different mechanisms on the bacterial growth thereby providing for better antibacterial activity. Thermodynamically stable ME was developed and characterized with an average particle size of 17.58 nm, further confirmed by TEM analysis. Antibacterial studies included chequerboard microdilution assay to determine the MIC and fractional inhibitory concentration (FIC) of both the natural compounds individually and in combination. MIC and FIC results indicated that the combination of the above two natural compounds was proficient in lowering the MICs of individual agents. Results of DPPH assay indicated that ME system preserved the long term antioxidative potential of P60 and caffeine. The cytotoxicity of the optimized formulation on Vero cell line by MTT assay was found to be nontoxic to mammalian cells.

  13. Caffeine suppresses exercise-enhanced long-term and location memory in middle-aged rats: Involvement of hippocampal Akt and CREB signaling.

    PubMed

    Cechella, José L; Leite, Marlon R; da Rocha, Juliana T; Dobrachinski, Fernando; Gai, Bibiana M; Soares, Félix A A; Bresciani, Guilherme; Royes, Luiz F F; Zeni, Gilson

    2014-11-05

    The cognitive function decline is closely related with brain changes generated by age. The ability of caffeine and exercise to prevent memory impairment has been reported in animal models and humans. The purpose of the present study was to investigate whether swimming exercise and caffeine administration enhance memory in middle-aged Wistar rats. Male Wistar rats (18months) received caffeine at a dose of 30mg/kg, 5days per week by a period of 4weeks. Animals were subjected to swimming training with a workload (3% of body weight, 20min per day for 4weeks). After 4weeks, the object recognition test (ORT) and the object location test (OLT) were performed. The results of this study demonstrated that caffeine suppressed exercise-enhanced long-term (ORT) and spatial (OLT) memory in middle-aged and this effect may be related to a decrease in hippocampal p-CREB signaling. This study also provided evidence that the effects of this protocol on memory were not accompanied by alterations in the levels of activated Akt. The [(3)H] glutamate uptake was reduced in hippocampus of rats administered with caffeine and submitted to swimming protocol.

  14. Unequal Probability Marking Approach to Enhance Security of Traceback Scheme in Tree-Based WSNs

    PubMed Central

    Huang, Changqin; Ma, Ming; Liu, Xiao; Liu, Anfeng; Zuo, Zhengbang

    2017-01-01

    Fog (from core to edge) computing is a newly emerging computing platform, which utilizes a large number of network devices at the edge of a network to provide ubiquitous computing, thus having great development potential. However, the issue of security poses an important challenge for fog computing. In particular, the Internet of Things (IoT) that constitutes the fog computing platform is crucial for preserving the security of a huge number of wireless sensors, which are vulnerable to attack. In this paper, a new unequal probability marking approach is proposed to enhance the security performance of logging and migration traceback (LM) schemes in tree-based wireless sensor networks (WSNs). The main contribution of this paper is to overcome the deficiency of the LM scheme that has a higher network lifetime and large storage space. In the unequal probability marking logging and migration (UPLM) scheme of this paper, different marking probabilities are adopted for different nodes according to their distances to the sink. A large marking probability is assigned to nodes in remote areas (areas at a long distance from the sink), while a small marking probability is applied to nodes in nearby area (areas at a short distance from the sink). This reduces the consumption of storage and energy in addition to enhancing the security performance, lifetime, and storage capacity. Marking information will be migrated to nodes at a longer distance from the sink for increasing the amount of stored marking information, thus enhancing the security performance in the process of migration. The experimental simulation shows that for general tree-based WSNs, the UPLM scheme proposed in this paper can store 1.12–1.28 times the amount of stored marking information that the equal probability marking approach achieves, and has 1.15–1.26 times the storage utilization efficiency compared with other schemes. PMID:28629135

  15. Unequal Probability Marking Approach to Enhance Security of Traceback Scheme in Tree-Based WSNs.

    PubMed

    Huang, Changqin; Ma, Ming; Liu, Xiao; Liu, Anfeng; Zuo, Zhengbang

    2017-06-17

    Fog (from core to edge) computing is a newly emerging computing platform, which utilizes a large number of network devices at the edge of a network to provide ubiquitous computing, thus having great development potential. However, the issue of security poses an important challenge for fog computing. In particular, the Internet of Things (IoT) that constitutes the fog computing platform is crucial for preserving the security of a huge number of wireless sensors, which are vulnerable to attack. In this paper, a new unequal probability marking approach is proposed to enhance the security performance of logging and migration traceback (LM) schemes in tree-based wireless sensor networks (WSNs). The main contribution of this paper is to overcome the deficiency of the LM scheme that has a higher network lifetime and large storage space. In the unequal probability marking logging and migration (UPLM) scheme of this paper, different marking probabilities are adopted for different nodes according to their distances to the sink. A large marking probability is assigned to nodes in remote areas (areas at a long distance from the sink), while a small marking probability is applied to nodes in nearby area (areas at a short distance from the sink). This reduces the consumption of storage and energy in addition to enhancing the security performance, lifetime, and storage capacity. Marking information will be migrated to nodes at a longer distance from the sink for increasing the amount of stored marking information, thus enhancing the security performance in the process of migration. The experimental simulation shows that for general tree-based WSNs, the UPLM scheme proposed in this paper can store 1.12-1.28 times the amount of stored marking information that the equal probability marking approach achieves, and has 1.15-1.26 times the storage utilization efficiency compared with other schemes.

  16. Expectation of having consumed caffeine can improve performance and mood.

    PubMed

    Dawkins, Lynne; Shahzad, Fatima-Zahra; Ahmed, Suada S; Edmonds, Caroline J

    2011-12-01

    We explored whether caffeine, and expectation of having consumed caffeine, affects attention, reward responsivity and mood using double-blinded methodology. 88 participants were randomly allocated to 'drink-type' (caffeinated/decaffeinated coffee) and 'expectancy' (told caffeinated/told decaffeinated coffee) manipulations. Both caffeine and expectation of having consumed caffeine improved attention and psychomotor speed. Expectation enhanced self-reported vigour and reward responsivity. Self-reported depression increased at post-drink for all participants, but less in those receiving or expecting caffeine. These results suggest caffeine expectation can affect mood and performance but do not support a synergistic effect. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Caffeine addiction? Caffeine for youth? Time to act!

    PubMed

    Budney, Alan J; Emond, Jennifer A

    2014-11-01

    While data accumulate and discussion evolves on the clinical importance of caffeine addiction and its classification, the growing practices of (i) adding increasing amounts of caffeine to drinks and other consumables, (ii) promoting these as performance enhancers and (iii) targeting youth as the consumer raise concerns that require immediate action.

  18. The Effects of Caffeine Use on Driving Safety Among Truck Drivers Who Are Habitual Caffeine Users.

    PubMed

    Heaton, Karen; Griffin, Russell

    2015-08-01

    The purpose of this study was to describe caffeine use among a group of habitual caffeine users, truck drivers, and to explore the associations between caffeine use and critical safety events by age in the naturalistic work setting. A secondary analysis of existing data from the Naturalistic Truck Driving Study was conducted. Analyses focused on the association between sleep and caffeine consumption by duty status, comparisons of sleep and caffeine use by age, and the associations between caffeine use and safety-critical events (SCEs). Findings indicated differences in caffeine use by duty status. However, no difference in sleep time by duty status, or between sleep time and caffeine use was found regardless of when the caffeine was consumed during the 5 hours prior to sleep. Sleep time did not vary significantly by age, although increasing age was associated with decreased caffeine use. Overall, a 6% reduction in the rate of SCEs per eight ounces of caffeinated beverage consumed was found. This study makes a unique scientific contribution because it uses real-time observations of truckers in the naturalistic work setting. It also does not involve caffeine withdrawal but rather an investigation of the effects of the naturalistic consumption of caffeine on sleep and driving performance. Findings suggest that caffeine use among habitual users offers a protective effect for safety-critical driving events. Occupational health nurses may use this information to counsel workers in the use of caffeine to enhance driving safety.

  19. Simultaneous multiplexed quantification of caffeine and its major metabolites theobromine and paraxanthine using surface-enhanced Raman scattering.

    PubMed

    Alharbi, Omar; Xu, Yun; Goodacre, Royston

    2015-11-01

    Accurate quantitative measurement of drugs and their metabolites is important as this can be used to establish long-term abuse of illicit materials as well as establish accurate drug dosing for legal therapeutics. However, the levels of drugs and xenometabolites found in human body fluids necessitate methods that are highly sensitive as well as reproducible with the potential for portability. Raman spectroscopy does offer excellent reproducibility, portability and chemical specificity, but unfortunately, the Raman effect is generally too weak unless it is enhanced. We therefore developed surface-enhanced Raman scattering (SERS) and combined it with the powerful machine learning technique of artificial neural networks to enable rapid quantification of caffeine and its two major metabolites theobromine and paraxanthine. We established a three-way mixture analysis from 10(-5) to 10(-7) mol/dm(3), and excellent predictions were generated for all three analytes in tertiary mixtures. The range we selected reflects the levels found in human body fluids, and the typical errors for our portable SERS analysis were 1.7 × 10(-6) mol/dm(3) for caffeine, 8.8 × 10(-7) mol/dm(3) for theobromine and 9.6 × 10(-7) mol/dm(3) for paraxanthine. We believe this demonstrates the exciting prospect of using SERS for the quantitative analysis of multiple analytes simultaneously without recourse to lengthy and time-consuming chromatography, a method that often has to be combined with mass spectrometry.

  20. Combination therapy with catechins and caffeine inhibits fat accumulation in 3T3-L1 cells

    PubMed Central

    Zhu, Xiaojuan; Yang, Licong; Xu, Feng; Lin, Lezhen; Zheng, Guodong

    2017-01-01

    Catechins and caffeine, which are green tea components, have a slimming effect; however, the combinational effect of fat metabolism in 3T3-L1 cells remains unclear. In the present study, 3T3-L1 cells were treated with catechins and caffeine in combination, and it was found that combination therapy with catechins and caffeine markedly reduced intracellular fat accumulation, mRNA expression levels of peroxisome proliferator-activated receptor-γ and CCAAT/enhancer-binding protein α in the early stage of cell differentiation were significantly reduced, and mRNA expression of fatty acid synthetase(FAS) andglycerol-3-phosphate dehydrogenase protein expression levels of FAS were downregulated. Noradrenaline-induced lipolysis was enhanced by caffeine, which markedly increased the protein expression of adipose triglyceride lipase and hormone sensitive lipase. These results indicated that combination therapy with catechins and caffeine synergistically inhibited lipid accumulation by regulating the gene and protein expression levels of lipid metabolism-related enzymes. Therefore, catechins and caffeine combination therapy has potential as a functional food that may be used to prevent obesity and lifestyle-associated diseases. PMID:28352352

  1. Combination therapy with catechins and caffeine inhibits fat accumulation in 3T3-L1 cells.

    PubMed

    Zhu, Xiaojuan; Yang, Licong; Xu, Feng; Lin, Lezhen; Zheng, Guodong

    2017-02-01

    Catechins and caffeine, which are green tea components, have a slimming effect; however, the combinational effect of fat metabolism in 3T3-L1 cells remains unclear. In the present study, 3T3-L1 cells were treated with catechins and caffeine in combination, and it was found that combination therapy with catechins and caffeine markedly reduced intracellular fat accumulation, mRNA expression levels of peroxisome proliferator-activated receptor-γ and CCAAT/enhancer-binding protein α in the early stage of cell differentiation were significantly reduced, and mRNA expression of fatty acid synthetase(FAS) andglycerol-3-phosphate dehydrogenase protein expression levels of FAS were downregulated. Noradrenaline-induced lipolysis was enhanced by caffeine, which markedly increased the protein expression of adipose triglyceride lipase and hormone sensitive lipase. These results indicated that combination therapy with catechins and caffeine synergistically inhibited lipid accumulation by regulating the gene and protein expression levels of lipid metabolism-related enzymes. Therefore, catechins and caffeine combination therapy has potential as a functional food that may be used to prevent obesity and lifestyle-associated diseases.

  2. Make Caffeine Visible: a Fluorescent Caffeine “Traffic Light” Detector

    NASA Astrophysics Data System (ADS)

    Xu, Wang; Kim, Tae-Hyeong; Zhai, Duanting; Er, Jun Cheng; Zhang, Liyun; Kale, Anup Atul; Agrawalla, Bikram Keshari; Cho, Yoon-Kyoung; Chang, Young-Tae

    2013-07-01

    Caffeine has attracted abundant attention due to its extensive existence in beverages and medicines. However, to detect it sensitively and conveniently remains a challenge, especially in resource-limited regions. Here we report a novel aqueous phase fluorescent caffeine sensor named Caffeine Orange which exhibits 250-fold fluorescence enhancement upon caffeine activation and high selectivity. Nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy indicate that π-stacking and hydrogen-bonding contribute to their interactions while dynamic light scattering and transmission electron microscopy experiments demonstrate the change of Caffeine Orange ambient environment induces its fluorescence emission. To utilize this probe in real life, we developed a non-toxic caffeine detection kit and tested it for caffeine quantification in various beverages. Naked-eye sensing of various caffeine concentrations was possible based on color changes upon irradiation with a laser pointer. Lastly, we performed the whole system on a microfluidic device to make caffeine detection quick, sensitive and automated.

  3. Make Caffeine Visible: a Fluorescent Caffeine “Traffic Light” Detector

    PubMed Central

    Xu, Wang; Kim, Tae-Hyeong; Zhai, Duanting; Er, Jun Cheng; Zhang, Liyun; Kale, Anup Atul; Agrawalla, Bikram Keshari; Cho, Yoon-Kyoung; Chang, Young-Tae

    2013-01-01

    Caffeine has attracted abundant attention due to its extensive existence in beverages and medicines. However, to detect it sensitively and conveniently remains a challenge, especially in resource-limited regions. Here we report a novel aqueous phase fluorescent caffeine sensor named Caffeine Orange which exhibits 250-fold fluorescence enhancement upon caffeine activation and high selectivity. Nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy indicate that π-stacking and hydrogen-bonding contribute to their interactions while dynamic light scattering and transmission electron microscopy experiments demonstrate the change of Caffeine Orange ambient environment induces its fluorescence emission. To utilize this probe in real life, we developed a non-toxic caffeine detection kit and tested it for caffeine quantification in various beverages. Naked-eye sensing of various caffeine concentrations was possible based on color changes upon irradiation with a laser pointer. Lastly, we performed the whole system on a microfluidic device to make caffeine detection quick, sensitive and automated. PMID:23877095

  4. Caffeine: sleep and daytime sleepiness.

    PubMed

    Roehrs, Timothy; Roth, Thomas

    2008-04-01

    Caffeine is one of the most widely consumed psychoactive substances and it has profound effects on sleep and wake function. Laboratory studies have documented its sleep-disruptive effects. It clearly enhances alertness and performance in studies with explicit sleep deprivation, restriction, or circadian sleep schedule reversals. But, under conditions of habitual sleep the evidence indicates that caffeine, rather then enhancing performance, is merely restoring performance degraded by sleepiness. The sleepiness and degraded function may be due to basal sleep insufficiency, circadian sleep schedule reversals, rebound sleepiness, and/or a withdrawal syndrome after the acute, over-night, caffeine discontinuation typical of most studies. Studies have shown that caffeine dependence develops at relatively low daily doses and after short periods of regular daily use. Large sample and population-based studies indicate that regular daily dietary caffeine intake is associated with disturbed sleep and associated daytime sleepiness. Further, children and adolescents, while reporting lower daily, weight-corrected caffeine intake, similarly experience sleep disturbance and daytime sleepiness associated with their caffeine use. The risks to sleep and alertness of regular caffeine use are greatly underestimated by both the general population and physicians.

  5. Diazepam and caffeine administration during the first week of life: changes in neonatal and adolescent behavior.

    PubMed

    File, S E

    1987-01-01

    The male offspring of hooded Lister rats were fostered at birth into 23 experimental litters. One pup in each litter was allocated to each of the following treatment groups: vehicle control; caffeine (15 or 30 mg/kg); diazepam (10 mg/kg, alone or plus caffeine 15 or 30 mg/kg). Pups were given daily injections on neonatal days 1-7 and were observed for 15 min following each injection. Diazepam significantly increased paddling and forward walking, particularly on days 5 and 7; caffeine also increased these behaviors, but less markedly. Diazepam increased the incidence of clonic jerks, particularly on day 7 and increased the spontaneous loss of righting reflex. The pups were then left undisturbed until weaning at day 21 and testing from days 35-42. There were no lasting effects of the neonatal treatments in two tests of anxiety, or in passive avoidance performance. Rats that had been treated neonatally with diazepam had significantly lower motor activity scores and reared less in the holeboard than did controls, and neonatal treatment with caffeine also resulted in lower motor activity scores. Neonatal treatment with caffeine made rats more aggressive (increased kicking and pushing) when they were intruding into another rat's territory. Neonatal treatment with diazepam increased aggression in resident rats, and this was counteracted by neonatal treatment with caffeine. Neonatal caffeine treatment enhanced rats' unconditioned preference for the black chamber in a black-white preference test and neonatal diazepam treatment reduced it.

  6. The effects of caffeine on tension development and intracellular calcium transients in rat ventricular muscle.

    PubMed Central

    Konishi, M; Kurihara, S; Sakai, T

    1984-01-01

    The effects of caffeine on tension and intracellular [Ca2+] were investigated in rat ventricular muscle using the Ca2+-sensitive photoprotein, aequorin. Contracture was induced by rapid application of 0.5-10 mM-caffeine solution at 20 degrees C. In normal Tyrode solution at 8 degrees C, or in Na+-deficient solution in which Na+ was isotonically replaced by sucrose, peak tension of caffeine contracture was potentiated and relaxation was prolonged. Caffeine contracture could not be induced immediately after a prior contracture. Repriming time was 10 min in Tyrode solution, and was much shorter in Na+-deficient solution or in high-K+ solution containing 105.9 mM-K+. Caffeine prolonged the plateau of action potential dose dependently. At low temperature, prolongation of the plateau phase by caffeine was more marked. Twitch tension showed a triphasic change after application of caffeine; peak tension transiently increased in a potentiating phase (P phase), and then decreased below control level in an inhibitory phase (I phase) followed by gradual recovery in a recovery phase (R phase). The effects of caffeine on the Ca2+ transients during a twitch were also complex, depending on time after application and dose of caffeine. In low caffeine concentration (below 0.5 mM) the peak of the Ca2+ transient was potentiated in the I phase, although the peak tension was suppressed. At high concentration (above 3 mM) the peaks of both the Ca2+ transient and twitch tension were suppressed. In every concentration of caffeine tested (0.1-5 mM), time to the Ca2+ transient and twitch tension peaks was prolonged, and the falling phases of both were delayed. Caffeine might release Ca2+ from intracellular store(s) and enhance the slow inward current. The Ca2+ transient obtained in this study clearly indicate that the prolonged time to peak tension in the presence of caffeine is due to the slow rise of intracellular [Ca2+] and prolonged time to peak of the Ca2+ transient. It is also quite

  7. Dietary Caffeine and Polyphenol Supplementation Enhances Overall Metabolic Rate and Lipid Oxidation at Rest and After a Bout of Sprint Interval Exercise.

    PubMed

    Jo, Edward; Lewis, Kiana L; Higuera, Daniel; Hernandez, Joshua; Osmond, Adam D; Directo, Dean J; Wong, Michael

    2016-07-01

    Jo, E, Lewis, KL, Higuera, D, Hernandez, J, Osmond, AD, Directo, DJ, and Wong, M. Dietary caffeine and polyphenol supplementation enhances overall metabolic rate and lipid oxidation at rest and after a bout of sprint interval exercise. J Strength Cond Res 30(7): 1871-1879, 2016-The purpose of this study was to investigate the effects of a caffeine-polyphenolic supplement on (a) metabolic rate and fat oxidation at rest and after a bout of sprint interval exercise (SIE) and (b) SIE performance. In a double-blind, randomized, placebo-controlled, crossover study and after an initial familiarization visit, 12 subjects (male: n = 11; female: n = 1) (body mass = 76.1 ± 2.2 kg; height = 169.8 ± 1.6 cm; body mass index = 22.7 ± 3.0 kg·m; body fat % = 21.6 ± 2.0%) underwent 2 testing sessions during which time they consumed either a caffeine-polyphenol supplement or placebo. After supplementation, resting energy expenditure, heart rate (HR), and blood pressure (BP) were assessed. Subsequently, subjects performed 30 minutes of SIE while researchers collected performance data. Subjects were then tested for post-SIE energy expenditure, HR, and BP. The caffeine-polyphenol treatment resulted in significantly (p ≤ 0.05) greater energy expenditure (+7.99% rest; +10.16% post-SIE), V[Combining Dot Above]O2 (+9.64% rest; +12.10% post-SIE), and fat oxidation rate (+10.60% rest; +9.76% post-SIE) vs. placebo at rest and post-SIE. No significant differences were detected for peak and average power at all sprint intervals between treatments. Post-SIE HR was significantly (p ≤ 0.05) greater with caffeine-polyphenol supplementation vs. placebo (90.8 ± 3.5 vs. 85.1 ± 3.6 b·min). There were no significant between-treatment differences for BP. It may be concluded that the observed thermogenic response after SIE was directly attributable to caffeine-polyphenol supplementation as opposed to an indirect manifestation of enhanced performance and work output. Collectively, these results

  8. Use of Taguchi methodology to enhance the yield of caffeine removal with growing cultures of Pseudomonas pseudoalcaligenes.

    PubMed

    Ashengroph, Morahem; Ababaf, Sajad

    2014-12-01

    Microbial caffeine removal is a green solution for treatment of caffeinated products and agro-industrial effluents. We directed this investigation to optimizing a bio-decaffeination process with growing cultures of Pseudomonas pseudoalcaligenes through Taguchi methodology which is a structured statistical approach that can be lowered variations in a process through Design of Experiments (DOE). Five parameters, i.e. initial fructose, tryptone, Zn(+2) ion and caffeine concentrations and also incubation time selected and an L16 orthogonal array was applied to design experiments with four 4-level factors and one 3-level factor (4(4) × 1(3)). Data analysis was performed using the statistical analysis of variance (ANOVA) method. Furthermore, the optimal conditions were determined by combining the optimal levels of the significant factors and verified by a confirming experiment. Measurement of residual caffeine concentration in the reaction mixture was performed using high-performance liquid chromatography (HPLC). Use of Taguchi methodology for optimization of design parameters resulted in about 86.14% reduction of caffeine in 48 h incubation when 5g/l fructose, 3 mM Zn(+2) ion and 4.5 g/l of caffeine are present in the designed media. Under the optimized conditions, the yield of degradation of caffeine (4.5 g/l) by the native strain of Pseudomonas pseudoalcaligenes TPS8 has been increased from 15.8% to 86.14% which is 5.4 fold higher than the normal yield. According to the experimental results, Taguchi methodology provides a powerful methodology for identifying the favorable parameters on caffeine removal using strain TPS8 which suggests that the approach also has potential application with similar strains to improve the yield of caffeine removal from caffeine containing solutions.

  9. The Janus face of caffeine.

    PubMed

    Porciúncula, Lisiane O; Sallaberry, Cássia; Mioranzza, Sabrina; Botton, Paulo Henrique S; Rosemberg, Denis B

    2013-11-01

    Caffeine is certainly the psychostimulant substance most consumed worldwide. Over the past years, chronic consumption of caffeine has been associated with prevention of cognitive decline associated to aging and mnemonic deficits of brain disorders. While its preventive effects have been reported extensively, the cognitive enhancer properties of caffeine are relatively under debate. Surprisingly, there are scarce detailed ontogenetic studies focusing on neurochemical parameters related to the effects of caffeine during prenatal and earlier postnatal periods. Furthermore, despite the large number of epidemiological studies, it remains unclear how safe is caffeine consumption during pregnancy and brain development. Thus, the purpose of this article is to review what is currently known about the actions of caffeine intake on neurobehavioral and adenosinergic system during brain development. We also reviewed other neurochemical systems affected by caffeine, but not only during brain development. Besides, some recent epidemiological studies were also outlined with the control of "pregnancy signal" as confounding variable. The idea is to tease out how studies on the impact of caffeine consumption during brain development deserve more attention and further investigation.

  10. Caffeine enhances the antidepressant-like activity of common antidepressant drugs in the forced swim test in mice.

    PubMed

    Szopa, Aleksandra; Poleszak, Ewa; Wyska, Elżbieta; Serefko, Anna; Wośko, Sylwia; Wlaź, Aleksandra; Pieróg, Mateusz; Wróbel, Andrzej; Wlaź, Piotr

    2016-02-01

    Caffeine is the most widely used behaviorally active drug in the world which exerts its activity on central nervous system through adenosine receptors. Worrying data indicate that excessive caffeine intake applies to patients suffering from mental disorders, including depression. The main goal of the present study was to evaluate the influence of caffeine on animals' behavior in forced swim test (FST) as well as the effect of caffeine (5 mg/kg) on the activity of six typical antidepressants, such as imipramine (15 mg/kg), desipramine (10 mg/kg), fluoxetine (5 mg/kg), paroxetine (0.5 mg/kg), escitalopram (2 mg/kg), and reboxetine (2.5 mg/kg). Locomotor activity was estimated to verify and exclude false-positive/negative results. In order to assess the influence of caffeine on the levels of antidepressant drugs studied, their concentrations were determined in murine serum and brains using high-performance liquid chromatography. The results showed that caffeine at a dose of 10, 20, and 50 mg/kg exhibited antidepressant activity in the FST, and it was not related to changes in locomotor activity in the animals. Caffeine at a dose of 5 mg/kg potentiated the activity of all antidepressants, and the observed effects were not due to the increase in locomotor activity in the animals. The interactions between caffeine and desipramine, fluoxetine, escitalopram, and reboxetine were exclusively of pharmacodynamic character, because caffeine did not cause any changes in the concentrations of these drugs neither in blood serum nor in brain tissue. As a result of joint administration of caffeine and paroxetine, an increase in the antidepressant drug concentrations in serum was observed. No such change was noticed in the brain tissue. A decrease in the antidepressant drug concentrations in brain was observed in the case of imipramine administered together with caffeine. Therefore, it can be assumed that the interactions caffeine-paroxetine and caffeine-imipramine occur at least in

  11. Caffeine tolerance: behavioral, electrophysiological and neurochemical evidence

    SciTech Connect

    Chou, D.T.; Khan, S.; Forde, J.; Hirsh, K.R.

    1985-06-17

    The development of tolerance to the stimulatory action of caffeine upon mesencephalic reticular neurons and upon spontaneous locomotor activity was evaluated in rats after two weeks of chronic exposure to low doses of caffeine (5-10 mg/kg/day via their drinking water). These doses are achievable through dietary intake of caffeine-containing beverages in man. Concomitant measurement of (/sup 3/H)-CHA binding in the mesencephalic reticular formation was also carried out in order to explore the neurochemical basis of the development of tolerance. Caffeine, 2.5 mg/kg i.v., markedly increased the firing rate of reticular neurons in caffeine naive rats but failed to modify the neuronal activity in a group exposed chronically to low doses of caffeine. In addition, in spontaneous locomotor activity studies, the data show a distinct shift to the right of the caffeine dose-response curve in caffeine pretreated rats. These results clearly indicate that tolerance develops to the stimulatory action of caffeine upon the reticular formation at the single neuronal activity level as well as upon spontaneous locomotor activity. Furthermore, in chronically caffeine exposed rats, an increase in the number of binding sites for (/sup 3/H)-CHA was observed in reticular formation membranes without any change in receptor affinity. 28 references, 4 figures.

  12. Caffeine impairs the acquisition and retention, but not the consolidation of Pavlovian conditioned freezing in mice

    PubMed Central

    Dubroqua, Sylvain; Low, Samuel R.L.; Yee, Benjamin K.; Singer, Philipp

    2014-01-01

    Rationale The psychoactive substance, caffeine may improve cognitive performance, but its direct impact on learning and memory remains ill-defined. Conflicting reports suggest that caffeine may impair as well as enhance Pavlovian fear conditioning in animals, and its effect may vary across different phases of learning. Objectives To dissect the effect of a motor-stimulant dose of caffeine (30 mg/kg i.p.) on acquisition, retrieval or consolidation of conditioned fear in C57BL/6 mice. Methods Fear conditioning was evaluated in a conditioned freezing paradigm comprising 3 tone-shock pairings and a two-way active avoidance paradigm lasting two consecutive days with 80 conditioning trials per test session. Results Conditioning to both the discrete tone conditioned stimulus (CS) and the context was markedly impaired by caffeine. The deficits were similarly evident when caffeine was administered prior to acquisition or retrieval (48 and 72 h after conditioning); and the most severe impairment was seen in animals given caffeine before acquisition and before retrieval. A comparable deficit was observed in the conditioned active avoidance test. By contrast, caffeine administered immediately following acquisition neither affected the expression of tone freezing nor context freezing. Conclusions The present study challenges the previous report that caffeine primarily disrupts hippocampus-dependent conditioning to the context. At the relevant dose range, acute caffeine likely exerts more widespread impacts beyond the hippocampus, including amygdala and striatum that are anatomically connected to the hippocampus; and together they support the acquisition and retention of fear memories to discrete stimuli as well as diffused contextual cues. PMID:25172668

  13. The vascular prepattern enhancer trap marks early vascular development in arabidopsis.

    PubMed

    Holding, David R; Springer, Patricia S

    2002-08-01

    Vascular development is a fundamental component of leaf morphogenesis, and the mechanisms that control vascular patterning are poorly understood. We report here the identification of an enhancer trap line, Vascular Prepattern (VPP), that acts as a marker for early vascular development. GUS reporter gene expression in VPP was detected in provascular cells from the earliest stages of primary midvein formation in leaf primordia and subsequently coincided with the early specification of higher order veins. GUS expression in VPP also marks the quiescent center cells of the root apical meristem at all stages of root development. VPP provides a marker for early vascular development and will be a useful tool for studying vascular patterning.

  14. The effect of mark enhancement techniques on the subsequent detection of saliva.

    PubMed

    McAllister, Patricia; Graham, Eleanor; Deacon, Paul; Farrugia, Kevin J

    2016-09-01

    There appears to be a limited but growing body of research on the sequential analysis/treatment of multiple types of evidence. The development of an integrated forensic approach is necessary to maximise evidence recovery and to ensure that a particular treatment is not detrimental to other types of evidence. This study aims to assess the effect of latent and blood mark enhancement techniques (e.g. fluorescence, ninhydrin, acid violet 17, black iron-oxide powder suspension) on the subsequent detection of saliva. Saliva detection was performed by means of a presumptive test (Phadebas®) in addition to analysis by a rapid stain identification (RSID) kit test and confirmatory DNA testing. Additional variables included a saliva depletion series and a number of different substrates with varying porosities as well as different ageing periods. Examination and photography under white light and fluorescence was carried out prior to and after chemical enhancement. All enhancement techniques (except Bluestar® Forensic Magnum luminol) employed in this study resulted in an improved visualisation of the saliva stains, although the inherent fluorescence of saliva was sometimes blocked after chemical treatment. The use of protein stains was, in general, detrimental to the detection of saliva. Positive results were less pronounced after the use of black iron-oxide powder suspension, cyanoacrylate fuming followed by BY40 and ninhydrin when compared to the respective positive controls. The application of Bluestar® Forensic Magnum luminol and black magnetic powder proved to be the least detrimental, with no significant difference between the test results and the positive controls. The use of non-destructive fluorescence examination provided good visualisation; however, only the first few marks in the depletion were observed. Of the samples selected for DNA analysis only depletion 1 samples contained sufficient DNA quantity for further processing using standard methodology. The 28-day

  15. Caffeine, exercise and the brain.

    PubMed

    Meeusen, Romain; Roelands, Bart; Spriet, Lawrence L

    2013-01-01

    Caffeine can improve exercise performance when it is ingested at moderate doses (3-6 mg/kg body mass). Caffeine also has an effect on the central nervous system (CNS), and it is now recognized that most of the performance-enhancing effect of caffeine is accomplished through the antagonism of the adenosine receptors, influencing the dopaminergic and other neurotransmitter systems. Adenosine and dopamine interact in the brain, and this might be one mechanism to explain how the important components of motivation (i.e. vigor, persistence and work output) and higher-order brain processes are involved in motor control. Caffeine maintains a higher dopamine concentration especially in those brain areas linked with 'attention'. Through this neurochemical interaction, caffeine improves sustained attention, vigilance, and reduces symptoms of fatigue. Other aspects that are localized in the CNS are a reduction in skeletal muscle pain and force sensation, leading to a reduction in perception of effort during exercise and therefore influencing the motivational factors to sustain effort during exercise. Because not all CNS aspects have been examined in detail, one should consider that a placebo effect may also be present. Overall, it appears that the performance-enhancing effects of caffeine reside in the brain, although more research is necessary to reveal the exact mechanisms through which the CNS effect is established.

  16. Caffeine and Your Child

    MedlinePlus

    ... dream of giving their kids a mug of coffee, but might routinely serve soft drinks containing caffeine. Foods and drinks with caffeine are everywhere, but it's wise to keep caffeine consumption to a minimum, especially in younger kids. The ...

  17. Caffeine and Your Child

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old Caffeine and Your Child KidsHealth > For Parents > Caffeine and ... 12-ounce (355-milliliter) can of soda. How Caffeine Affects Kids A stimulant that affects kids and ...

  18. A hypothalamic–pituitary–adrenal axis-associated neuroendocrine metabolic programmed alteration in offspring rats of IUGR induced by prenatal caffeine ingestion

    SciTech Connect

    Xu, D.; Wu, Y.; Liu, F.; Liu, Y.S.; Shen, L.; Lei, Y.Y.; Liu, J.; Ping, J.; Qin, J.; Zhang, C.; Chen, L.B.; Magdalou, J.; Wang, H.

    2012-11-01

    Caffeine is a definite factor of intrauterine growth retardation (IUGR). Previously, we have confirmed that prenatal caffeine ingestion inhibits the development of hypothalamic–pituitary–adrenal (HPA) axis, and alters the glucose and lipid metabolism in IUGR fetal rats. In this study, we aimed to verify a programmed alteration of neuroendocrine metabolism in prenatal caffeine ingested-offspring rats. The results showed that prenatal caffeine (120 mg/kg.day) ingestion caused low body weight and high IUGR rate of pups; the concentrations of blood adrenocorticotropic hormone (ACTH) and corticosterone in caffeine group were significantly increased in the early postnatal period followed by falling in late stage; the level of blood glucose was unchanged, while blood total cholesterol (TCH) and triglyceride (TG) were markedly enhanced in adult. After chronic stress, the concentrations and the gain rates of blood ACTH and corticosterone were obviously increased, meanwhile, the blood glucose increased while the TCH and TG decreased in caffeine group. Further, the hippocampal mineralocorticoid receptor (MR) expression in caffeine group was initially decreased and subsequently increased after birth. After chronic stress, the 11β-hydroxysteroid dehydrogenase-1, glucocorticoid receptor (GR), MR as well as the MR/GR ratio were all significantly decreased. These results suggested that prenatal caffeine ingestion induced the dysfunction of HPA axis and associated neuroendocrine metabolic programmed alteration in IUGR offspring rats, which might be related with the functional injury of hippocampus. These observations provide a valuable experimental basis for explaining the susceptibility of IUGR offspring to metabolic syndrome and associated diseases. -- Highlights: ► Prenatal caffeine ingestion induced HPA axis dysfunction in IUGR offspring rats. ► Caffeine induced a neuroendocrine metabolic programmed alteration in offspring rats. ► Caffeine induced a functional injury

  19. Caffeine reduces myocardial blood flow during exercise.

    PubMed

    Higgins, John P; Babu, Kavita M

    2013-08-01

    Caffeine consumption has been receiving increased interest from both the medical and lay press, especially given the increased amounts now available in energy products. Acute ingestion of caffeine usually increases cardiac work; however, caffeine impairs the expected proportional increase in myocardial blood flow to match this increased work of the heart, most notably during exercise. This appears to be mainly due to caffeine's effect on blocking adenosine-induced vasodilatation in the coronary arteries in normal healthy subjects. This review summarizes the available medical literature specifically relating to pure caffeine tablet ingestion and reduced exercise coronary blood flow, and suggests possible mechanisms. Further studies are needed to evaluate this effect for other common caffeine-delivery systems, including coffee, energy beverages, and energy gels, which are often used for exercise performance enhancement, especially in teenagers and young athletes.

  20. Low-dose repeated caffeine administration for circadian-phase-dependent performance degradation during extended wakefulness.

    PubMed

    Wyatt, James K; Cajochen, Christian; Ritz-De Cecco, Angela; Czeisler, Charles A; Dijk, Derk-Jan

    2004-05-01

    To investigate whether the effectiveness of a novel high-frequency low-dose caffeine regimen in counteracting the deterioration of performance during extended wakefulness is related to its interaction with homeostatic or circadian signals modulating performance and sleep propensity. Double-blind, placebo-controlled, parallel-group design in a 29-day forced desynchrony paradigm in which the period of the sleep-wake cycle was scheduled to be 42.85 hours, i.e., far removed from the circadian range. This design allowed for separate estimation of the sleep homeostatic, circadian, and caffeine contributions to performance deficits or improvements. Private suite of a general clinical research center, in the absence of time of day information. Sixteen healthy normal-sleeping men (aged 18-30 years) Caffeine (0.3 mg per kg per hour) or placebo was administered hourly during the 28.57-hour wake episodes. Plasma caffeine concentrations rose in an exponential saturating manner during wakefulness. Rising caffeine levels markedly attenuated wake-dependent deterioration of a number of measures of cognitive performance, particularly at the circadian performance nadir. Moreover, caffeine enhanced the ability of subjects to remain consistently awake for extended periods, holding subjects back from completing the full transition to sleep, but at the expense of increasing subjective sleepiness. High-frequency low-dose caffeine administration is effective in countering the detrimental performance effects of extended wakefulness. These data are in accordance with the hypothesis that adenosine is a mediator of performance decrements associated with extended wakefulness and may lead to new strategies to use caffeine in situations in which neurobehavioral functioning is affected by sleep loss.

  1. Cyclosporin A markedly enhances superantigen-induced peripheral T cell deletion and inhibits anergy induction

    PubMed Central

    1992-01-01

    Cyclosporin A (CsA) is a well-known immunosuppressive agent that modulates immune tolerance in many ways. CsA can give rise to a state of long-term nonimmunosuppressed transplantation tolerance, but it can also aggravate autoimmune diseases, and provoke specific forms of autoimmunity. These effects, which are often paradoxical, remain largely unexplained. In this study, we investigated the effects of CsA on superantigen (superAg)-reactive peripheral T cells. The intravenous injection of either staphylococcal enterotoxin B (SEB), or Mls-1a cells into Mls-1b recipients, causes long-term in vitro nonresponsiveness (anergy) and partial elimination of the peripheral T cell receptor (TCR) V beta 8+/CD4+ and -V beta 6+/CD4+ T cell subsets, respectively. We report that CsA markedly enhances the peripheral elimination of SEB- and Mls-1a-reactive T cells such that up to 90% of the targeted CD4+/V beta subpopulations are deleted. The degree of deletion depends on the dose and the schedule of CsA administration, and the number of superAg injections. In situations where the extent of deletion is only moderate, we find that the remaining superAg-reactive T cells fail to develop anergy, unlike the T cells of control superAg-immunized mice. Higher doses of CsA are required to enhance T cell deletion (greater than or equal to 25 mg/kg/d, i.p.) than to impair anergy induction (greater than or equal to 6.25 mg/kg/d, i.p.). In view of these results, it appears that the degree of tolerance in CsA/superAg-treated mice depends on the balance between these opposing effects, i.e., enhancement of peripheral elimination versus the abrogation of anergy. The possibility of enhancing or preventing immune tolerance with a drug may have important clinical implications. PMID:1613464

  2. Mood and performance effects of caffeine in relation to acute and chronic caffeine deprivation.

    PubMed

    Richardson, N J; Rogers, P J; Elliman, N A; O'Dell, R J

    1995-10-01

    The mood and performance effects of caffeine deprivation (either 90 min, overnight, or at least 7 days) and ingestion (70 and 250 mg) were compared in young adults who were normally either moderate consumers (n = 49) or nonconsumers of caffeine (n = 18). Overnight caffeine deprivation produced dysphoric symptoms characteristic of caffeine withdrawal that were reduced, but still present, after longer-term abstinence. Acute caffeine intake affected the withdrawn consumers, nonwithdrawn consumers, and nonconsumers similarly. It increased jitteriness and decrease tiredness and headache. Furthermore, hand steadiness decreased as caffeine dose increased, whereas 70 mg, but not 250 mg, of caffeine was found to enhance performance on a simple reaction time task. These findings support the view that the negative effects experienced after overnight and longer-term caffeine deprivation play a significant role in influencing consumption of caffeine-containing drinks. Therefore, it would appear that to avoid the dysphoric symptoms resulting from both under- and overconsumption, regular caffeine consumers would have to regulate their caffeine intake fairly precisely.

  3. Caffeine Expectancy Questionnaire (CaffEQ): construction, psychometric properties, and associations with caffeine use, caffeine dependence, and other related variables.

    PubMed

    Huntley, Edward D; Juliano, Laura M

    2012-09-01

    Expectancies for drug effects predict drug initiation, use, cessation, and relapse, and may play a causal role in drug effects (i.e., placebo effects). Surprisingly little is known about expectancies for caffeine even though it is the most widely used psychoactive drug in the world. In a series of independent studies, the nature and scope of caffeine expectancies among caffeine consumers and nonconsumers were assessed, and a comprehensive and psychometrically sound Caffeine Expectancy Questionnaire (CaffEQ) was developed. After 2 preliminary studies, the CaffEQ was administered to 1,046 individuals from the general population along with other measures of interest (e.g., caffeine use history, anxiety). Exploratory factor analysis of the CaffEQ yielded a 7-factor solution. Subsequently, an independent sample of 665 individuals completed the CaffEQ and other measures, and a subset (n = 440) completed the CaffEQ again approximately 2 weeks later. Confirmatory factor analysis revealed good model fit, and test-retest reliability was very good. The frequency and quantity of caffeine use were associated with greater expectancies for withdrawal/dependence, energy/work enhancement, appetite suppression, social/mood enhancement, and physical performance enhancement and lower expectancies for anxiety/negative physical effects and sleep disturbance. Caffeine expectancies predicted various caffeine- associated features of substance dependence (e.g., use despite harm, withdrawal incidence and severity, perceived difficulty stopping use, tolerance). Expectancies for caffeine consumed via coffee were stronger than for caffeine consumed via soft drinks or tea. The CaffEQ should facilitate the advancement of our knowledge of caffeine and drug use in general.

  4. Caffeine, cognition, and socioeconomic status.

    PubMed

    Kyle, Janet; Fox, Helen C; Whalley, Lawrence J

    2010-01-01

    There is interest in age-related cognitive decline and environmental risk factors for Alzheimer's disease (AD). This interest is focused on individual differences in exposure to agents that may harm or protect cognitive function. Caffeine is used as a short acting mental stimulant and may possess longer-term properties that protect against age-related decline and, possibly, AD. The current study aimed to: 1) examine current cognitive function in a narrow age range sample (n=351) without dementia (MMSE>25) who are, by reason of age, entering the period of increased risk of AD; and 2) link cognitive function to self-reported intake of caffeine and socioeconomic status (SES). Possible confounding by gender, childhood intelligence, education, and symptoms of anxiety and depression was introduced into the statistical model. There were significant differences between SES groups in caffeine intake (p< 0.05) and cognitive performance (p< 0.001). Higher quartiles of caffeine intake were associated with slower digit symbol speed (F =3.38, p< 0.02) but this finding was removed after allowing for SES. The results are discussed in terms of the withdrawal effects of caffeine during cognitive testing and strong links between SES and cognitive performance. No evidence in support of cognitive enhancing effects of caffeine was found.

  5. The effect of mark enhancement techniques on the subsequent detection of semen/spermatozoa.

    PubMed

    Simmons, Rory; Deacon, Paul; Phillips, Darren J; Farrugia, Kevin

    2014-11-01

    Fingermarks, footwear marks, blood and semen are amongst the most commonly encountered types of evidence at crime scenes. Previous work has extensively investigated fingermark and blood enhancement techniques and a sequence developed to maximise evidence recovery; however, there is limited research as to the effect of these techniques on the subsequent detection of body fluids such as semen. In this study, seven fingermark and blood enhancement techniques (e.g. powder suspension, cyanoacrylate fuming and acid violet 17) were employed followed by the subsequent detection of semen/spermatozoa. Other variables included in the study were the use of two substrates (white ceramic tiles and grey laminate flooring), a depletion series and ageing periods of 1, 7, 14 and 28 days. The effect these techniques had on the subsequent detection of semen was assessed by visual and fluorescence examination followed by presumptive and confirmatory testing for semen and spermatozoa. The results found that protein stains (acid violet 17 and acid yellow 7) caused a loss in presumptive test reactivity; however, sperm heads were still observed using microscopic examination after extraction and staining. The use of black magnetic powder, Bluestar(®) Forensic Magnum luminol, Lumicyano™ 4% and cyanoacrylate fuming followed by basic yellow 40 staining did not hinder subsequent presumptive and confirmatory tests for semen and sperm heads. Powder suspension caused a loss in both presumptive test reactivity and sperm heads from the substrate. In general, the enhancement techniques resulted in the improved visualisation of the semen stains under white and violet/blue light. The results from this study aim to provide a strategy to maximise evidence recovery and improve efficiency in an integrated forensic approach.

  6. Effect of caffeine on induction of endogenous type C virus in mouse cells in vitro

    SciTech Connect

    Niwa, O.; Sugahara, T.

    1981-08-01

    The effect of caffeine on the expression of murine endogenous virus in mouse cells induced by radiation and chemicals was studied. Postirradiation treatment of K-BALB cells with caffeine enhanced cell killing as well as the induction of xenotropic virus after ultraviolet light irradiation. The degree of enhancement for the virus induction was comparable to that for cell killing. On the other hand, colony-forming ability and the expression of xenotropic virus of K-BALB cells after X-irradiation were unaffected by caffeine. These data suggest a linear relationship between the degree of endogenous virus expression and the amount of lethal damages after irradiation. For induction by halogenated pyrimidines, a 24-hr incubation of AKR2B cells with caffeine after 5-iodo-2'-deoxyuridine treatment resulted in marked suppression of the expression of ecotropic virus. On the contrary, in K-BALB cells, caffeine exerted only a small effect on 5-iodo-2'-deoxyuridine-induced expression of ecotropic and xenotropic viruses. These results indicate that, although using the same inducing agent, the pathway of endogenous virus induction may be different for AKR2B cells and for K-BALB cells.

  7. Caffeine fostering of mycoparasitic fungi against phytopathogens.

    PubMed

    Sugiyama, Akifumi; Sano, Cecile M; Yazaki, Kazufumi; Sano, Hiroshi

    2016-01-01

    Caffeine (1,3,7-trimethixanthine) is a typical purine alkaloid produced in more than 80 plant species. Its biological role is considered to strengthen plant's defense capabilities, directly as a toxicant to biotic attackers (allelopathy) and indirectly as an activator of defense system (priming). Caffeine is actively secreted into rhizosphere through primary root, and possibly affects the structure of microbe community nearby. The fungal community in coffee plant rhizosphere is enriched with particular species, including Trichoderma family, a mycoparasite that attacks and kills phytopathogens by coiling and destroying their hyphae. In the present study, the caffeine response of 8 filamentous fungi, 4 mycoparasitic Trichoderma, and 4 prey phytopathogens, was examined. Results showed that allelopathic effect of caffeine on fungal growth and development was differential, being stronger on pathogens than on Trichoderma species. Upon confronting, the prey immediately ceased the growth, whereas the predator continued to grow, indicating active mycoparasitism to have occurred. Caffeine enhanced mycoparasitism up to 1.7-fold. Caffeine thus functions in a double-track manner against fungal pathogens: first by direct suppression of growth and development, and second by assisting their natural enemy. These observations suggest that caffeine is a powerful weapon in the arms race between plants and pathogens by fostering enemy's enemy, and we propose the idea of "caffeine fostering" as the third role of caffeine.

  8. Caffeine fostering of mycoparasitic fungi against phytopathogens

    PubMed Central

    Sugiyama, Akifumi; Sano, Cecile M.; Yazaki, Kazufumi; Sano, Hiroshi

    2016-01-01

    Caffeine (1,3,7-trimethixanthine) is a typical purine alkaloid produced in more than 80 plant species. Its biological role is considered to strengthen plant's defense capabilities, directly as a toxicant to biotic attackers (allelopathy) and indirectly as an activator of defense system (priming). Caffeine is actively secreted into rhizosphere through primary root, and possibly affects the structure of microbe community nearby. The fungal community in coffee plant rhizosphere is enriched with particular species, including Trichoderma family, a mycoparasite that attacks and kills phytopathogens by coiling and destroying their hyphae. In the present study, the caffeine response of 8 filamentous fungi, 4 mycoparasitic Trichoderma, and 4 prey phytopathogens, was examined. Results showed that allelopathic effect of caffeine on fungal growth and development was differential, being stronger on pathogens than on Trichoderma species. Upon confronting, the prey immediately ceased the growth, whereas the predator continued to grow, indicating active mycoparasitism to have occurred. Caffeine enhanced mycoparasitism up to 1.7-fold. Caffeine thus functions in a double-track manner against fungal pathogens: first by direct suppression of growth and development, and second by assisting their natural enemy. These observations suggest that caffeine is a powerful weapon in the arms race between plants and pathogens by fostering enemy's enemy, and we propose the idea of "caffeine fostering" as the third role of caffeine. PMID:26529400

  9. SpDamID: Marking DNA Bound by Protein Complexes Identifies Notch-Dimer Responsive Enhancers.

    PubMed

    Hass, Matthew R; Liow, Hien-Haw; Chen, Xiaoting; Sharma, Ankur; Inoue, Yukiko U; Inoue, Takayoshi; Reeb, Ashley; Martens, Andrew; Fulbright, Mary; Raju, Saravanan; Stevens, Michael; Boyle, Scott; Park, Joo-Seop; Weirauch, Matthew T; Brent, Michael R; Kopan, Raphael

    2015-08-20

    We developed Split DamID (SpDamID), a protein complementation version of DamID, to mark genomic DNA bound in vivo by interacting or juxtapositioned transcription factors. Inactive halves of DAM (DNA adenine methyltransferase) were fused to protein pairs to be queried. Either direct interaction between proteins or proximity enabled DAM reconstitution and methylation of adenine in GATC. Inducible SpDamID was used to analyze Notch-mediated transcriptional activation. We demonstrate that Notch complexes label RBP sites broadly across the genome and show that a subset of these complexes that recruit MAML and p300 undergo changes in chromatin accessibility in response to Notch signaling. SpDamID differentiates between monomeric and dimeric binding, thereby allowing for identification of half-site motifs used by Notch dimers. Motif enrichment of Notch enhancers coupled with SpDamID reveals co-targeting of regulatory sequences by Notch and Runx1. SpDamID represents a sensitive and powerful tool that enables dynamic analysis of combinatorial protein-DNA transactions at a genome-wide level.

  10. SpDamID: Marking DNA Bound by Protein Complexes Identifies Notch-Dimer Responsive Enhancers

    PubMed Central

    Hass, Matthew R.; Liow, Hien-haw; Chen, Xiaoting; Sharma, Ankur; Inoue, Yukiko U.; Inoue, Takayoshi; Reeb, Ashley; Martens, Andrew; Fulbright, Mary; Raju, Saravanan; Stevens, Michael; Boyle, Scott; Park, Joo-Seop; Weirauch, Matthew T.; Brent, Michael; Kopan, Raphael

    2015-01-01

    SUMMARY We developed Split DamID (SpDamID), a protein complementation version of DamID, to mark genomic DNA bound in vivo by interacting or juxtapositioned transcription factors. Inactive halves of DAM (DNA Adenine Methyltransferase) were fused to protein pairs to be queried Interaction or proximity enabled DAM reconstitution and methylation of adenine in GATC. Inducible SpDamID was used to analyze Notch-mediated transcriptional activation. We demonstrate that Notch complexes label RBP sites broadly across the genome, and show that a subset of these complexes that recruit MAML and p300 undergo changes in chromatin accessibility in response to Notch signaling. SpDamID differentiates between monomeric and dimeric binding thereby allowing for identification of half-site motifs used by Notch dimers. Motif enrichment of Notch enhancers coupled with SpDamID reveals co-targeting of regulatory sequences by Notch and Runx1. SpDamID represents a sensitive and powerful tool that enables dynamic analysis of combinatorial protein-DNA transactions at a genome-wide level. PMID:26257285

  11. Adolescent Attitudes and Beliefs Regarding Caffeine and the Consumption of Caffeinated Beverages.

    PubMed

    Turton, Paige; Piché, Len; Battram, Danielle S

    2016-03-01

    To explore adolescents' attitudes and beliefs toward the consumption of caffeinated beverages and factors influencing their caffeinated beverage choice and consumption patterns. Twenty focus groups were conducted with grades 9 to 12 secondary school students. Two secondary schools in London, Ontario, Canada. This study included 166 adolescents, 42% of whom were male and 72% of whom were in grades 9 and 10. Adolescent views regarding caffeine and caffeinated beverages. Three researchers independently conducted inductive content analysis on the data using the principles of the immersion-crystallization method. Awareness levels regarding types of caffeinated beverages and their negative health effects were high in adolescents whereas awareness of other aspects of caffeine itself and recommended consumption levels were low. Adolescents also identified reasons for caffeine use, including providing energy, taste, accessibility, and image enhancement. Influences for caffeine use most noted by participants included parental role modeling, media and advertising, and social norms. Further education is needed to correct the misconceptions adolescents have regarding certain aspects of caffeine. By gaining a deeper understanding of adolescents' caffeine use, effective educational strategies may be developed to reduce its use and mitigate potential harms. Copyright © 2016 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

  12. Caffeine and exercise: metabolism, endurance and performance.

    PubMed

    Graham, T E

    2001-01-01

    Caffeine is a common substance in the diets of most athletes and it is now appearing in many new products, including energy drinks, sport gels, alcoholic beverages and diet aids. It can be a powerful ergogenic aid at levels that are considerably lower than the acceptable limit of the International Olympic Committee and could be beneficial in training and in competition. Caffeine does not improve maximal oxygen capacity directly, but could permit the athlete to train at a greater power output and/or to train longer. It has also been shown to increase speed and/or power output in simulated race conditions. These effects have been found in activities that last as little as 60 seconds or as long as 2 hours. There is less information about the effects of caffeine on strength; however, recent work suggests no effect on maximal ability, but enhanced endurance or resistance to fatigue. There is no evidence that caffeine ingestion before exercise leads to dehydration, ion imbalance, or any other adverse effects. The ingestion of caffeine as coffee appears to be ineffective compared to doping with pure caffeine. Related compounds such as theophylline are also potent ergogenic aids. Caffeine may act synergistically with other drugs including ephedrine and anti-inflammatory agents. It appears that male and female athletes have similar caffeine pharmacokinetics, i.e., for a given dose of caffeine, the time course and absolute plasma concentrations of caffeine and its metabolites are the same. In addition, exercise or dehydration does not affect caffeine pharmacokinetics. The limited information available suggests that caffeine non-users and users respond similarly and that withdrawal from caffeine may not be important. The mechanism(s) by which caffeine elicits its ergogenic effects are unknown, but the popular theory that it enhances fat oxidation and spares muscle glycogen has very little support and is an incomplete explanation at best. Caffeine may work, in part, by

  13. Faster but not smarter: effects of caffeine and caffeine withdrawal on alertness and performance.

    PubMed

    Rogers, Peter J; Heatherley, Susan V; Mullings, Emma L; Smith, Jessica E

    2013-03-01

    Despite 100 years of psychopharmacological research, the extent to which caffeine consumption benefits human functioning remains unclear. To measure the effects of overnight caffeine abstinence and caffeine administration as a function of level of habitual caffeine consumption. Medium-high (n = 212) and non-low (n = 157) caffeine consumers completed self-report measures and computer-based tasks before (starting at 10:30 AM) and after double-blind treatment with either caffeine (100 mg, then 150 mg) or placebo. The first treatment was given at 11:15 AM and the second at 12:45 PM, with post-treatment measures repeated twice between 1:45 PM and 3:30 PM. Caffeine withdrawal was associated with some detrimental effects at 10:30 AM, and more severe effects, including greater sleepiness, lower mental alertness, and poorer performance on simple reaction time, choice reaction time and recognition memory tasks, later in the afternoon. Caffeine improved these measures in medium-high consumers but, apart from decreasing sleepiness, had little effect on them in non-low consumers. The failure of caffeine to increase mental alertness and improve mental performance in non-low consumers was related to a substantial caffeine-induced increase in anxiety/jitteriness that offset the benefit of decreased sleepiness. Caffeine enhanced physical performance (faster tapping speed and faster simple and choice reaction times) in both medium-high and non-low consumers. While caffeine benefits motor performance and tolerance develops to its tendency to increase anxiety/jitteriness, tolerance to its effects on sleepiness means that frequent consumption fails to enhance mental alertness and mental performance.

  14. Caffeine Promotes Global Spatial Processing in Habitual and Non-Habitual Caffeine Consumers

    PubMed Central

    Giles, Grace E.; Mahoney, Caroline R.; Brunyé, Tad T.; Taylor, Holly A.; Kanarek, Robin B.

    2013-01-01

    Information processing is generally biased toward global cues, often at the expense of local information. Equivocal extant data suggests that arousal states may accentuate either a local or global processing bias, at least partially dependent on the nature of the manipulation, task, and stimuli. To further differentiate the conditions responsible for such equivocal results we varied caffeine doses to alter physiological arousal states and measured their effect on tasks requiring the retrieval of local versus global spatial knowledge. In a double-blind, repeated-measures design, non-habitual (Experiment 1; N = 36, M = 42.5 ± 28.7 mg/day caffeine) and habitual (Experiment 2; N = 34, M = 579.5 ± 311.5 mg/day caffeine) caffeine consumers completed four test sessions corresponding to each of four caffeine doses (0, 100, 200, 400 mg). During each test session, participants consumed a capsule containing one of the three doses of caffeine or placebo, waited 60 min, and then completed two spatial tasks, one involving memorizing maps and one spatial descriptions. A spatial statement verification task tested local versus global spatial knowledge by differentially probing memory for proximal versus distal landmark relationships. On the map learning task, results indicated that caffeine enhanced memory for distal (i.e., global) compared to proximal (i.e., local) comparisons at 100 (marginal), 200, and 400 mg caffeine in non-habitual consumers, and marginally beginning at 200 mg caffeine in habitual consumers. On the spatial descriptions task, caffeine enhanced memory for distal compared to proximal comparisons beginning at 100 mg in non-habitual but not habitual consumers. We thus provide evidence that caffeine-induced physiological arousal amplifies global spatial processing biases, and these effects are at least partially driven by habitual caffeine consumption. PMID:24146646

  15. Hidden in Plain Sight: How Ventral Line Markings in Chameleons May Enhance Camouflage.

    PubMed

    Resetarits, Emlyn J; Raxworthy, Christopher J

    2016-02-01

    Chameleons, lizards often synonymous with camouflage for their color-changing abilities, possess a variety of permanent coloration patterns whose evolutionary significance remains largely unknown. In this study, we explore the potential for white ventral line markings in species across the genus Chamaeleonidae to function as a camouflage pattern against diurnal predators. Diurnal behavioral field studies of the white-lined chameleon Furcifer viridis showed that individuals typically exposed ventral line markings during the characteristic ring-flip antipredator behavior in response to a predatory threat. These ventral line markings are largely inconspicuous in other postures. Comparative morphological analyses of 86 species found that there was a significant positive correlation between ventral line markings with arboreal habitat type, even when accounting for phylogeny. These results suggest that ventral line markings (and the ring-flip behavior) could act as a disruptive or mimetic coloration marking for arboreal chameleons against visual diurnal predators. Further work testing differential predation rates is necessary in order to verify the proposed function of these line markings.

  16. [Caffeine in analgesics--myth or medicine?].

    PubMed

    Petersen, K U

    2013-12-16

    Caffeine as an analgesic adiuvant has been discussed for many years. In a recent Cochrane review based on 19 studies with a total of 7238 patients, caffeine enhanced the efficacy of paracetamol, ibuprofen or aspirin with a number needed to treat (NNT) of about 16, comparable to the effect of doubling the dose of the primary analgesic, reported by other authors. Analgesia by caffeine is best explained by antagonism at adenosine receptors. Recent studies confirmed a favourable tolerability profile of caffeine when consumed in "normal" quantities (e.g. 300 mg or about 3 cups of coffee per day), including possible cardiovascular risks, effects on bone density, and exposure in pregnancy. Beneficial effects are known,e.g.,in Parkinson's disease and liver cirrhosis and fibrosis. Caffeine remains an analgesic adiuvant with a favourable risk-benefit balance.

  17. Dose response of caffeine on 2000-m rowing performance.

    PubMed

    Skinner, Tina L; Jenkins, David G; Coombes, Jeff S; Taaffe, Dennis R; Leveritt, Michael D

    2010-03-01

    To determine whether a dose-response relationship exists between caffeine and 2000-m rowing performance. In this randomized, placebo-controlled, double-blind crossover study, 10 competitive male rowers (mean +/- SD: age = 20.6 +/- 1.4 yr, body mass = 87.7 +/- 10.5 kg, height = 186.8 +/- 6.8 cm, (.)VO2peak = 5.1 +/- 0.6 L x min(-1)) consumed 2, 4, or 6 mg x kg(-1) caffeine or a placebo 60 min before completing a 2000-m time trial on a rowing ergometer. The trials were preceded by a 24-h standardized diet (including a light preexercise meal of 2 g x kg(-1) CHO), and subjects were tested preexercise for hydration, caffeine abstinence, and blood glucose concentrations. Time trial performance was not significantly different across the three caffeine doses or placebo (P = 0.249). After the three caffeine trials, postexercise plasma glucose and lactate concentrations were higher compared with the placebo trial (P < 0.05). Plasma caffeine concentrations after 60 min of ingestion were lower than the values reported previously by others following the same dose, and there was considerable interindividual variation in plasma caffeine concentrations in response to the various caffeine doses. The large interindividual response to the caffeine doses suggests that individual characteristics need to be considered when administering caffeine for performance enhancement. In addition, preexercise feeding may significantly affect plasma caffeine concentrations and the potential for caffeine to improve performance.

  18. Adolescent Caffeine Consumption and Self-Reported Violence and Conduct Disorder

    ERIC Educational Resources Information Center

    Kristjansson, Alfgeir L.; Sigfusdottir, Inga Dora; Frost, Stephanie S.; James, Jack E.

    2013-01-01

    Caffeine is the most widely used psychoactive substance in the world and currently the only one legally available to children and adolescents. The sale and use of caffeinated beverages has increased markedly among adolescents during the last decade. However, research on caffeine use and behaviors among adolescents is scarce. We investigate the…

  19. Adolescent Caffeine Consumption and Self-Reported Violence and Conduct Disorder

    ERIC Educational Resources Information Center

    Kristjansson, Alfgeir L.; Sigfusdottir, Inga Dora; Frost, Stephanie S.; James, Jack E.

    2013-01-01

    Caffeine is the most widely used psychoactive substance in the world and currently the only one legally available to children and adolescents. The sale and use of caffeinated beverages has increased markedly among adolescents during the last decade. However, research on caffeine use and behaviors among adolescents is scarce. We investigate the…

  20. Different Ca2+ releasing action of caffeine and depolarisation in skeletal muscle fibres of the rat

    PubMed Central

    Lamb, G D; Cellini, M A; Stephenson, D G

    2001-01-01

    The relative abilities of caffeine and transverse tubular (T-) system depolarisation to induce Ca2+ release in mammalian skeletal muscle were compared in mechanically skinned fibres of the rat, in order to determine whether normal excitation-contraction (E-C) coupling is achieved by up-regulating the Ca2+-induced Ca2+ release process, as caffeine is known to do. Caffeine triggered Ca2+ release in soleus (slow-twitch) fibres at much lower concentrations than in extensor digitorum longus (EDL) (fast-twitch) fibres when the sarcoplasmic reticulum (SR) of each type was loaded with Ca2+ at close to endogenous levels. The difference in caffeine sensitivity resulted at least in part from the SR being loaded endogenously at near maximal capacity in soleus fibres but at less than half of maximal capacity in EDL fibres. The caffeine sensitivity could be reversed by reversing the relative level of SR loading. The ability of caffeine to induce Ca2+ release was markedly reduced by lowering the level of SR loading or by raising the free [Mg2+] from 1 to 3 mm. Caffeine, even at 30 mm, triggered little or no Ca2+ release in EDL fibres (a) at 1 mm (physiological) Mg2+ when the SR was loaded at two-thirds or less of the endogenous level, and (b) at 3 mm Mg2+ when the SR was loaded at close to the endogenous level. In contrast, depolarisation potently elicited Ca2+ release under these conditions in the same fibres. The inability of 30 mm caffeine to induce Ca2+ release under certain conditions was not attributable to desensitisation or inactivation of the release channels, because there was no response even upon initial exposure to caffeine and depolarisation always remained able to trigger Ca2+ release. It instead appeared that caffeine was a relatively ineffectual stimulus in EDL fibres except under conditions where (a) the SR was heavily loaded, (b) the free [Mg2+] was low, or (c) a high [Cl−] was present. These results show that the normal E-C coupling mechanism in mammalian

  1. Repeated sprint ability is not enhanced by caffeine, arginine, and branched-chain amino acids in moderately trained soccer players

    PubMed Central

    Ermolao, Andrea; Zanotto, Tobia; Carraro, Nicolò; Fornasier, Tommaso; Zaccaria, Marco; Neunhaeuserer, Daniel; Bergamin, Marco

    2017-01-01

    The aim was to investigate the effect of a dietary supplementation on the repeated sprint ability (RSA) performance in recreationally trained team sports athletes. Twelve young men underwent a RSA exercise protocol in five trials, in which participants ingested carbohydrates (CHO) plus caffeine (Caf), CHO plus arginine (Arg), CHO plus branched-chain amino acids (BCAA), CHO plus Caf, Arg, and BCAA (ALL), and CHO only. Heart rate, oxygen saturation, hematic lactate, ratings of perceived exertion, average sprint time, total time, best sprint time, peak power, and average power were taken. Data revealed no significant effects neither on physiological nor performance parameters with any of the supplements. PMID:28349034

  2. Repeated sprint ability is not enhanced by caffeine, arginine, and branched-chain amino acids in moderately trained soccer players.

    PubMed

    Ermolao, Andrea; Zanotto, Tobia; Carraro, Nicolò; Fornasier, Tommaso; Zaccaria, Marco; Neunhaeuserer, Daniel; Bergamin, Marco

    2017-02-01

    The aim was to investigate the effect of a dietary supplementation on the repeated sprint ability (RSA) performance in recreationally trained team sports athletes. Twelve young men underwent a RSA exercise protocol in five trials, in which participants ingested carbohydrates (CHO) plus caffeine (Caf), CHO plus arginine (Arg), CHO plus branched-chain amino acids (BCAA), CHO plus Caf, Arg, and BCAA (ALL), and CHO only. Heart rate, oxygen saturation, hematic lactate, ratings of perceived exertion, average sprint time, total time, best sprint time, peak power, and average power were taken. Data revealed no significant effects neither on physiological nor performance parameters with any of the supplements.

  3. Relationship between caffeine-induced ocular hypertension and ultrastructure changes of non-pigmented ciliary epithelial cells in rats.

    PubMed

    Kurata, K; Maeda, M; Nishida, E; Tsukuda, R; Suzuki, T; Ando, T; Tokuriki, M

    1997-12-01

    The purpose of this study was to morphologically assess a possible mechanism for caffeine-induced ocular hypertension. Taking into consideration the relationship between the secretion of aqueous humor and the ultrastructure of the ciliary body, the time course of the morphological features in the ciliary epithelium when caffeine was administered intravenously to male Wistar rats was investigated by electron-microscopy. These morphological findings were also compared with the changes in the intraocular pressure (IOP). A significant increase in IOP was noted 15 min and 1 hr after a single dosing of caffeine alone. This change disappeared in all animals within 2 hr after dosing. The IOP in the animals receiving caffeine and the beta-blocker befunolol, which lowers the IOP by inhibiting aqueous humor secretion, decreased significantly from 15 min after dosing, and this change persisted 2 hr after dosing. In electron-microscopy 15 min and/or 1 hr after dosing with caffeine, a slight dilatation in the lateral intercellular spaces near the basement membrane of the non-pigmented ciliary epithelium was observed and the interdigitations between the non-pigmented epithelial cells were intact. Reversal of these changes was observed 2 hr after dosing. On the other hand, the lateral intercellular spaces between the non-pigmented epithelial cells were markedly dilated and the interdigitations were disorganized following dosing with caffeine alone and in combination with befunolol. These results described here indicate that the intravenous administration of caffeine causes ocular hypertension and also changes in the non-pigmented ciliary epithelium, suggesting an enhancement of aqueous humor transportation. This paradigm in the rat is considered to be useful to further assess caffeine-induced ocular hypertension and for use as an animal model in glaucoma research associated with an aqueous humor secretion.

  4. Performance effects and metabolic consequences of caffeine and caffeinated energy drink consumption on glucose disposal.

    PubMed

    Shearer, Jane; Graham, Terry E

    2014-10-01

    This review documents two opposing effects of caffeine and caffeine-containing energy drinks, i.e., their positive effects on athletic performance and their negative impacts on glucose tolerance in the sedentary state. Analysis of studies examining caffeine administration prior to performance-based exercise showed caffeine improved completion time by 3.6%. Similar analyses following consumption of caffeine-containing energy drinks yielded positive, but more varied, benefits, which were likely due to the diverse nature of the studies performed, the highly variable composition of the beverages consumed, and the range of caffeine doses administered. Conversely, analyses of studies administering caffeine prior to either an oral glucose tolerance test or insulin clamp showed a decline in whole-body glucose disposal of ~30%. The consequences of this resistance are unknown, but there may be implications for the development of a number of chronic diseases. Both caffeine-induced performance enhancement and insulin resistance converge with the primary actions of caffeine on skeletal muscle.

  5. Caffeine Content Labeling: A Missed Opportunity for Promoting Personal and Public Health

    PubMed Central

    Kole, Jon

    2013-01-01

    Current regulation of caffeine-containing products is incoherent, fails to protect consumers' interests, and should be modified in multiple ways. We make the case for one of the regulatory reforms that are needed: all consumable products containing added caffeine should be required by the Food and Drug Administration (FDA) to include caffeine quantity on their labels. Currently, no foods or beverages that contain caffeine are required to include caffeine content on their labels. Strengthening these lax labeling requirements could prevent direct caffeine-induced harm, protect those most vulnerable to caffeine-related side effects, and enhance consumer autonomy and effective caffeine use. Consumers have an interest in regulating their intake of caffeine and thus, ought to know how much caffeine their foods and beverages contain. PMID:24761278

  6. Caffeine Content Labeling: A Missed Opportunity for Promoting Personal and Public Health.

    PubMed

    Kole, Jon; Barnhill, Anne

    2013-09-01

    Current regulation of caffeine-containing products is incoherent, fails to protect consumers' interests, and should be modified in multiple ways. We make the case for one of the regulatory reforms that are needed: all consumable products containing added caffeine should be required by the Food and Drug Administration (FDA) to include caffeine quantity on their labels. Currently, no foods or beverages that contain caffeine are required to include caffeine content on their labels. Strengthening these lax labeling requirements could prevent direct caffeine-induced harm, protect those most vulnerable to caffeine-related side effects, and enhance consumer autonomy and effective caffeine use. Consumers have an interest in regulating their intake of caffeine and thus, ought to know how much caffeine their foods and beverages contain.

  7. The pH dependent Raman spectroscopic study of caffeine

    NASA Astrophysics Data System (ADS)

    Kang, Jian; Gu, Huaimin; Zhong, Liang; Hu, Yongjun; Liu, Fang

    2011-02-01

    First of all the surface enhanced Raman spectroscopy (SERS) and normal Raman spectra of caffeine aqueous solution were obtained at different pH values. In order to obtain the detailed vibrational assignments of the Raman spectroscopy, the geometry of caffeine molecule was optimized by density functional theory (DFT) calculation. By comparing the SERS of caffeine with its normal spectra at different pH values; it is concluded that pH value can dramatically affect the SERS of caffeine, but barely affect the normal Raman spectrum of caffeine aqueous solution. It can essentially affect the reorientation of caffeine molecule to the Ag colloid surface, but cannot impact the vibration of functional groups and chemical bonds in caffeine molecule.

  8. Regular caffeine consumption: a balance of adverse and beneficial effects for mood and psychomotor performance.

    PubMed

    Rogers, P J; Dernoncourt, C

    1998-04-01

    It has often been pointed out that caffeine is the most widely "used" psychoactive substance in the world, and accordingly, there is a very large amount of research available on the effects of caffeine on body and mind. In particular, a psychostimulant action of caffeine is generally accepted as well established; for example, caffeine has been found to quicken reaction time and enhance vigilance performance, and to increase self-rated alertness and improve mood. There is, however, a real difficulty in determining the net effects of caffeine. In a typical experiment the subjects have a history of regular caffeine consumption, and they are tested on caffeine and a placebo after a period of caffeine deprivation (often overnight). The problem with relying solely on this approach is that it leaves open the question as to whether the results obtained are due to beneficial effects of caffeine or to deleterious effects of caffeine deprivation. The present article briefly reviews this evidence on the psychostimulant effects of caffeine, and presents some new data testing the hypothesis that caffeine may enhance cognitive performance to a greater extent in older adults than in young adults. No age-related differences in the effects of caffeine on psychomotor performance were found. We conclude that overall there is little unequivocal evidence to show that regular caffeine use is likely to substantially benefit mood or performance. Indeed, one of the significant factors motivating caffeine consumption appears to be "withdrawal relief."

  9. Aspirin, Butalbital, and Caffeine

    MedlinePlus

    The combination of aspirin, butalbital, and caffeine comes as a capsule and tablet to take by mouth. It usually is taken every 4 ... explain any part you do not understand. Take aspirin, butalbital, and caffeine exactly as directed. Do not ...

  10. Pioneer factor interactions and unmethylated CpG dinucleotides mark silent tissue-specific enhancers in embryonic stem cells.

    PubMed

    Xu, Jian; Pope, Scott D; Jazirehi, Ali R; Attema, Joanne L; Papathanasiou, Peter; Watts, Jason A; Zaret, Kenneth S; Weissman, Irving L; Smale, Stephen T

    2007-07-24

    Recent studies have suggested that, in ES cells, inactive genes encoding early developmental regulators possess bivalent histone modification domains and are therefore poised for activation. However, bivalent domains were not observed at typical tissue-specific genes. Here, we show that windows of unmethylated CpG dinucleotides and putative pioneer factor interactions mark enhancers for at least some tissue-specific genes in ES cells. The unmethylated windows expand in cells that express the gene and contract, disappear, or remain unchanged in nonexpressing tissues. However, in ES cells, they do not always coincide with common histone modifications. Genomic footprinting and chromatin immunoprecipitation demonstrated that transcription factor binding underlies the unmethylated windows at enhancers for the Ptcra and Alb1 genes. After stable integration of premethylated Ptcra enhancer constructs into the ES cell genome, the unmethylated windows readily appeared. In contrast, the premethylated constructs remained fully methylated and silent after introduction into Ptcra-expressing thymocytes. These findings provide initial functional support for a model in which pioneer factor interactions in ES cells promote the assembly of a chromatin structure that is permissive for subsequent activation, and in which differentiated tissues lack the machinery required for gene activation when these ES cell marks are absent. The enhancer marks may therefore represent important features of the pluripotent state.

  11. Oral administration of caffeine during voluntary exercise markedly decreases tissue fat and stimulates apoptosis and cyclin B1 in UVB-treated skin of hairless p53-knockout mice.

    PubMed

    Lou, Yourong; Peng, Qingyun; Nolan, Bonnie; Wagner, George C; Lu, Yaoping

    2010-04-01

    Treatment of p53(-/-) mice orally with caffeine, voluntary exercise or their combination for 2 weeks prior to a single irradiation with UVB (i) decreased the weight of the epididymal fat pads by 22, 40 and 56%, (ii) decreased the thickness of the dermal fat layer by 10, 26 and 42%, (iii) increased the number of apoptotic sunburn cells by 29, 100 and 489%, (iv) increased the number of caspase-3-positive cells by 33, 117 and 667% and (v) increased the number of mitotic cells with cyclin B1-positive staining by 40, 210 and 510%, respectively. Pearson's correlation coefficient indicated a statistically significant inverse relationship between the level of tissue fat and the number of mitotic cells with cyclin B1 in p53(-/-) mice but not in p53(+/+) littermates. Western blot analysis indicated that treatment of p53(-/-) mice with caffeine together with exercise increased the level of cyclin B1 significantly more than in p53(+/+) mice. p53(-/-) mice, but not p53(+/+) mice, treated with caffeine during exercise exhibited a dramatic decrease in the level of survivin. Our results suggest that voluntary exercise in combination with oral caffeine may exert a synergistic increase in UVB-induced apoptosis and that tissue fat may be a more important modulator of apoptosis and carcinogenesis in p53-deficient mice than in p53-normal mice. The stimulatory effects on apoptosis in p53(-/-) mice by the combination treatment might be associated with increased levels of cyclin B1 and decreased levels of survivin.

  12. Caffeine induces apoptosis by enhancement of autophagy via PI3K/Akt/mTOR/p70S6K inhibition.

    PubMed

    Saiki, Shinji; Sasazawa, Yukiko; Imamichi, Yoko; Kawajiri, Sumihiro; Fujimaki, Takahiro; Tanida, Isei; Kobayashi, Hiroki; Sato, Fumiaki; Sato, Shigeto; Ishikawa, Ken-Ichi; Imoto, Masaya; Hattori, Nobutaka

    2011-02-01

    Caffeine is one of the most frequently ingested neuroactive compounds. All known mechanisms of apoptosis induced by caffeine act through cell cycle modulation or p53 induction. It is currently unknown whether caffeine-induced apoptosis is associated with other cell death mechanisms, such as autophagy. Herein we show that caffeine increases both the levels of microtubule-associated protein 1 light chain 3-II and the number of autophagosomes, through the use of western blotting, electron microscopy and immunocytochemistry techniques. Phosphorylated p70 ribosomal protein S6 kinase (Thr389), S6 ribosomal protein (Ser235/236), 4E-BP1 (Thr37/46) and Akt (Ser473) were significantly decreased by caffeine. In contrast, ERK1/2 (Thr202/204) was increased by caffeine, suggesting an inhibition of the Akt/mTOR/p70S6K pathway and activation of the ERK1/2 pathway. Although insulin treatment phosphorylated Akt (Ser473) and led to autophagy suppression, the effect of insulin treatment was completely abolished by caffeine addition. Caffeine-induced autophagy was not completely blocked by inhibition of ERK1/2 by U0126. Caffeine induced reduction of mitochondrial membrane potentials and apoptosis in a dose-dependent manner, which was further attenuated by the inhibition of autophagy with 3-methyladenine or Atg7 siRNA knockdown. Furthermore, there was a reduced number of early apoptotic cells (annexin V positive, propidium iodide negative) among autophagy-deficient mouse embryonic fibroblasts treated with caffeine than their wild-type counterparts. These results support previous studies on the use of caffeine in the treatment of human tumors and indicate a potential new target in the regulation of apoptosis.

  13. Dietary fish oil delays hypoxic skeletal muscle fatigue and enhances caffeine-stimulated contractile recovery in the rat in vivo hindlimb.

    PubMed

    Peoples, Gregory E; McLennan, Peter L

    2017-06-01

    Oxygen efficiency influences skeletal muscle contractile function during physiological hypoxia. Dietary fish oil, providing docosahexaenoic acid (DHA), reduces the oxygen cost of muscle contraction. This study used an autologous perfused rat hindlimb model to examine the effects of a fish oil diet on skeletal muscle fatigue during an acute hypoxic challenge. Male Wistar rats were fed a diet rich in saturated fat (SF), long-chain (LC) n-6 polyunsaturated fatty acids (n-6 PUFA), or LC n-3 PUFA DHA from fish oil (FO) (8 weeks). During anaesthetised and ventilated conditions (normoxia 21% O2 (SaO2-98%) and hypoxia 14% O2 (SaO2-89%)) the hindlimb was perfused at a constant flow and the gastrocnemius-plantaris-soleus muscle bundle was stimulated via sciatic nerve (2 Hz, 6-12V, 0.05 ms) to established fatigue. Caffeine (2.5, 5, 10 mM) was supplied to the contracting muscle bundle via the arterial cannula to assess force recovery. Hypoxia, independent of diet, attenuated maximal twitch tension (normoxia: 82 ± 8; hypoxia: 41 ± 2 g·g(-1) tissue w.w.). However, rats fed FO sustained higher peak twitch tension compared with the SF and n-6 PUFA groups (P < 0.05), and the time to decline to 50% of maximum twitch tension was extended (SF: 546 ± 58; n-6 PUFA: 522 ± 58; FO: 792 ± 96 s; P < 0.05). In addition, caffeine-stimulated skeletal muscle contractile recovery was enhanced in the FO-fed animals (SF: 41 ± 3; n-6 PUFA: 40 ± 4; FO: 52 ± 7% recovery; P < 0.05). These results support a physiological role of DHA in skeletal muscle membranes when exposed to low-oxygen stress that is consistent with the attenuation of muscle fatigue under physiologically normoxic conditions.

  14. Acute effects of theanine, caffeine and theanine-caffeine combination on attention.

    PubMed

    Kahathuduwa, Chanaka N; Dassanayake, Tharaka L; Amarakoon, A M Tissa; Weerasinghe, Vajira S

    2017-07-01

    l-theanine is a constituent of tea which is claimed to enhance cognitive functions. We aimed to determine whether theanine and theanine-caffeine combination have acute positive effects on cognitive and neurophysiological measures of attention, compared to caffeine (a positive control) and a placebo in healthy individuals. In a placebo-controlled, five-way crossover trial in 20 healthy male volunteers, we compared the effects of l-theanine (200 mg), caffeine (160 mg), their combination, black tea (one cup) and a placebo (distilled water) on cognitive (simple [SVRT] and recognition visual reaction time [RVRT]) and neurophysiological (event-related potentials [ERPs]) measures of attention. We also recorded visual (VEPs) and motor evoked potentials (MEPs) to examine any effects of treatments on peripheral visual and motor conduction, respectively. Mean RVRT was significantly improved by theanine (P = 0.019), caffeine (P = 0.043), and theanine-caffeine combination (P = 0.001), but not by tea (P = 0.429) or placebo (P = 0.822). VEP or MEP latencies or SVRT did not show significant inter-treatment differences. Theanine (P = 0.001) and caffeine (P = 0.001) elicited significantly larger mean peak-to-peak N2-P300 ERP amplitudes than the placebo, whereas theanine-caffeine combination elicited a significantly larger mean N2-P300 amplitude than placebo (P < 0.001), theanine (P = 0.029) or caffeine (P = 0.005). No significant theanine × caffeine interaction was observed for RVRT or N2-P300 amplitude. A dose of theanine equivalent of eight cups of back tea improves cognitive and neurophysiological measures of selective attention, to a degree that is comparable with that of caffeine. Theanine and caffeine seem to have additive effects on attention in high doses.

  15. Caffeine enhances the expression of the angiotensin II Type 2 receptor mRNA in BeWo cell culture and in the rat placenta.

    PubMed

    Tanuma, A; Saito, S; Ide, I; Sasahara, H; Yazdani, M; Gottschalk, S; Nakamoto, T; Abiko, Y

    2003-07-01

    Although chronic caffeine exposure during pregnancy has been shown to affect fetal growth, adverse effects of caffeine on embryogenesis are not only well understood, but also controversial. We have used gene chip technology in an attempt to identify to what extent, if any, caffeine could possibly alter gene expressions in the cytotrophoblast-like cell line BeWo. Few down-regulated genes were found; most of the genes were up-regulated, suggesting that chronic caffeine exposure during the gestational period could exert certain influences on embryogenesis. The highest up-regulated gene expression of BeWo cells by caffeine was angiotensin II type 2 (AT(2)) receptor gene. We focused the genes of the renin-angiotensin system (RAS), angiotensin II type 1 (AT(1)) and AT(2)receptors and angiotensin I converting enzyme, for study on caffeine's responsive gene expression in BeWo cells and in the placentae of pregnant rats that were fed a diet supplemented with caffeine (2 mg/100 g body weight) during gestation, and analysed the gene expressions using RT-PCR and LightCycler system. A significantly increased AT(2)receptor gene expression and a slight decreased AT(1)receptor gene expression demonstrated the caffeine's effect to the placental RAS.

  16. Two Enhanced Heuristic Algorithms for the Minimum Initial Marking Problem of Petri Nets

    NASA Astrophysics Data System (ADS)

    Ochiiwa, Satoru; Taoka, Satoshi; Yamauchi, Masahiro; Watanabe, Toshimasa

    The minimum initial marking problem of Petri nets (MIM) is defined as follows: “Given a Petri net and a firing count vector X, find an initial marking M0, with the minimum total token number, for which there is a sequence δ of transitions such that each transition t appears exactly X(t) times in δ, the first transition is enabled at M0 and the rest can be fired one by one subsequently.” In a production system like factory automation, economical distribution of initial resources, from which a schedule of job-processings is executable, can be formulated as MIM. AAD is known to produce best solutions among existing algorithms. Although solutions by AMIM+ is worse than those by AAD, it is known that AMIM+ is very fast. This paper proposes new heuristic algorithms AADO and AMDLO, improved versions of existing algorithms AAD and AMIM+, respectively. Sharpness of solutions or short CPU time is the main target of AADO or AMDLO, respectively. It is shown, based on computing experiment, that the average total number of tokens in initial markings by AADO is about 5.15% less than that by AAD, and the average CPU time by AADO is about 17.3% of that by AAD. AMDLO produces solutions that are slightly worse than those by AAD, while they are about 10.4% better than those by AMIM+. Although CPU time of AMDLO is about 180 times that of AMIM+, it is still fast: average CPU time of AMDLO is about 2.33% of that of AAD. Generally it is observed that solutions get worse as the sizes of input instances increase, and this is the case with AAD and AMIM+. This undesirable tendency is greatly improved in AADO and AMDLO.

  17. Caffeine: Friend or Foe?

    PubMed

    Doepker, Candace; Lieberman, Harris R; Smith, Andrew Paul; Peck, Jennifer D; El-Sohemy, Ahmed; Welsh, Brian T

    2016-01-01

    The debate on the safety of and regulatory approaches for caffeine continues among various stakeholders and regulatory authorities. This decision-making process comes with significant challenges, particularly when considering the complexities of the available scientific data, making the formulation of clear science-based regulatory guidance more difficult. To allow for discussions of a number of key issues, the North American Branch of the International Life Sciences Institute (ILSI) convened a panel of subject matter experts for a caffeine-focused session entitled "Caffeine: Friend or Foe?," which was held during the 2015 ILSI Annual Meeting. The panelists' expertise covered topics ranging from the natural occurrence of caffeine in plants and interindividual metabolism of caffeine in humans to specific behavioral, reproductive, and cardiovascular effects related to caffeine consumption. Each presentation highlighted the potential risks, benefits, and challenges that inform whether caffeine exposure warrants concern. This paper aims to summarize the key topics discussed during the session.

  18. Obstacle Marking and Vehicle Guidance Science and Technology Objective (OMVG-STO) Augmented Reality for Enhanced Command and Control and Mobility

    DTIC Science & Technology

    2006-01-01

    OBSTACLE MARKING AND VEHICLE GUIDANCE SCIENCE AND TECHNOLOGY OBJECTIVE (OMVG-STO) AUGMENTED REALITY FOR ENHANCED COMMAND AND CONTROL AND MOBILITY...TITLE AND SUBTITLE Obstacle Marking and Vehicle Guidance Science and Technology Objective (OMVG-STO) Augmented Reality for Enhanced Command and Control

  19. Differential cognitive effects of energy drink ingredients: caffeine, taurine, and glucose.

    PubMed

    Giles, Grace E; Mahoney, Caroline R; Brunyé, Tad T; Gardony, Aaron L; Taylor, Holly A; Kanarek, Robin B

    2012-10-01

    Energy drinks containing caffeine, taurine, and glucose may improve mood and cognitive performance. However, there are no studies assessing the individual and interactive effects of these ingredients. We evaluated the effects of caffeine, taurine, and glucose alone and in combination on cognitive performance and mood in 24-hour caffeine-abstained habitual caffeine consumers. Using a randomized, double-blind, mixed design, 48 habitual caffeine consumers (18 male, 30 female) who were 24-hour caffeine deprived received one of four treatments (200 mg caffeine/0 mg taurine, 0 mg caffeine/2000 mg taurine, 200 mg caffeine/2000 mg taurine, 0 mg caffeine/0 mg taurine), on each of four separate days, separated by a 3-day wash-out period. Between-participants treatment was a glucose drink (50 g glucose, placebo). Salivary cortisol, mood and heart rate were measured. An attention task was administered 30-minutes post-treatment, followed by a working memory and reaction time task 60-minutes post-treatment. Caffeine enhanced executive control and working memory, and reduced simple and choice reaction time. Taurine increased choice reaction time but reduced reaction time in the working memory tasks. Glucose alone slowed choice reaction time. Glucose in combination with caffeine, enhanced object working memory and in combination with taurine, enhanced orienting attention. Limited glucose effects may reflect low task difficulty relative to subjects' cognitive ability. Caffeine reduced feelings of fatigue and increased tension and vigor. Taurine reversed the effects of caffeine on vigor and caffeine-withdrawal symptoms. No effects were found for salivary cortisol or heart rate. Caffeine, not taurine or glucose, is likely responsible for reported changes in cognitive performance following consumption of energy drinks, especially in caffeine-withdrawn habitual caffeine consumers.

  20. Caffeine Consumption by College Undergraduates.

    ERIC Educational Resources Information Center

    Loke, Wing Hong

    1988-01-01

    Surveyed 542 undergraduates concerning their caffeine consumption. Found that subjects consumed less caffeine than average caffeine-drinking population. Coffee was main beverage used. Subjects reported drinking more caffeine when preparing for examinations. Suggests that caffeine may have some beneficial effects on learning. (Author/NB)

  1. Caffeine Consumption by College Undergraduates.

    ERIC Educational Resources Information Center

    Loke, Wing Hong

    1988-01-01

    Surveyed 542 undergraduates concerning their caffeine consumption. Found that subjects consumed less caffeine than average caffeine-drinking population. Coffee was main beverage used. Subjects reported drinking more caffeine when preparing for examinations. Suggests that caffeine may have some beneficial effects on learning. (Author/NB)

  2. Evaluation of the reproductive and developmental risks of caffeine.

    PubMed

    Brent, Robert L; Christian, Mildred S; Diener, Robert M

    2011-04-01

    A risk analysis of in utero caffeine exposure is presented utilizing epidemiological studies and animal studies dealing with congenital malformation, pregnancy loss, and weight reduction. These effects are of interest to teratologists, because animal studies are useful in their evaluation. Many of the epidemiology studies did not evaluate the impact of the "pregnancy signal," which identifies healthy pregnancies and permits investigators to identify subjects with low pregnancy risks. The spontaneous abortion epidemiology studies were inconsistent and the majority did not consider the confounding introduced by not considering the pregnancy signal. The animal studies do not support the concept that caffeine is an abortafacient for the wide range of human caffeine exposures. Almost all the congenital malformation epidemiology studies were negative. Animal pharmacokinetic studies indicate that the teratogenic plasma level of caffeine has to reach or exceed 60 µg/ml, which is not attainable from ingesting large amounts of caffeine in foods and beverages. No epidemiological study described the "caffeine teratogenic syndrome." Six of the 17 recent epidemiology studies dealing with the risk of caffeine and fetal weight reduction were negative. Seven of the positive studies had growth reductions that were clinically insignificant and none of the studies cited the animal literature. Analysis of caffeine's reproductive toxicity considers reproducibility and plausibility of clinical, epidemiological, and animal data. Moderate or even high amounts of beverages and foods containing caffeine do not increase the risks of congenital malformations, miscarriage or growth retardation. Pharmacokinetic studies markedly improve the ability to perform the risk analyses.

  3. [Caffeine and children].

    PubMed

    D'ius, P B

    1997-01-01

    Beverages containing caffeine are consumed by most people in most countries most days. Consumption is mostly in beverages such as coffee, tea and some soft drinks, and smaller amounts from other foods such as chocolate. Children also consume caffeine, though in smaller amounts even relative to their smaller size. Many questions have been asked about possible health effects of caffeine and have been answered by scientific research. Studies on pregnant women consuming caffeine show no effects on the fetus, infants, or on development followed up to school age. There have been many studies on children of school age. For example, it has been shown that a single dose of 3 mg/kg is without appreciable effect on a variety of behavioral and physiological functions, and even 10 mg/kg, had only minimal effects, within the normal range of differences between the children without caffeine. While newborn infants metabolize caffeine slowly, children from less than 1 year to adolescence metabolize caffeine about twice as fast as non-smoking adults. The numerous studies showing safety of caffeine in adults, combined with the direct studies in children showing they are similar and not more susceptible to caffeine than adults, gives assurance that lifelong consumption of caffeine in foods and beverages, starting in childhood, is without deleterious effects on health.

  4. Caffeine's effects on true and false memory.

    PubMed

    Capek, Sarah; Guenther, R Kim

    2009-06-01

    Caffeine's effects on recall of word lists were investigated using the Deese-Roediger-McDermott (DRM) paradigm. College students were administered either 200 mg of caffeine or a 250-mg lactose placebo; after 30 min., they were tested on recall using six word lists. Words of each list were semantically related to a single word (a "critical lure") that was not presented in the list. Participants administered caffeine recalled more list words and more critical lures than participants administered lactose. Recall of list words was negatively correlated with recall of critical lures. Caffeine appears to intensify the strength of connections among list words and critical lures, thereby enhancing both true and false memory.

  5. Caffeine and anaerobic performance: ergogenic value and mechanisms of action.

    PubMed

    Davis, J K; Green, J Matt

    2009-01-01

    The effect caffeine elicits on endurance performance is well founded. However, comparatively less research has been conducted on the ergogenic potential of anaerobic performance. Some studies showing no effect of caffeine on performance used untrained subjects and designs often not conducive to observing an ergogenic effect. Recent studies incorporating trained subjects and paradigms specific to intermittent sports activity support the notion that caffeine is ergogenic to an extent with anaerobic exercise. Caffeine seems highly ergogenic for speed endurance exercise ranging in duration from 60 to 180 seconds. However, other traditional models examining power output (i.e. 30-second Wingate test) have shown minimal effect of caffeine on performance. Conversely, studies employing sport-specific methodologies (i.e. hockey, rugby, soccer) with shorter duration (i.e. 4-6 seconds) show caffeine to be ergogenic during high-intensity intermittent exercise. Recent studies show caffeine affects isometric maximal force and offers introductory evidence for enhanced muscle endurance for lower body musculature. However, isokinetic peak torque, one-repetition maximum and muscular endurance for upper body musculature are less clear. Since relatively few studies exist with resistance training, a definite conclusion cannot be reached on the extent caffeine affects performance. It was previously thought that caffeine mechanisms were associated with adrenaline (epinephrine)-induced enhanced free-fatty acid oxidation and consequent glycogen sparing, which is the leading hypothesis for the ergogenic effect. It would seem unlikely that the proposed theory would result in improved anaerobic performance, since exercise is dominated by oxygen-independent metabolic pathways. Other mechanisms for caffeine have been suggested, such as enhanced calcium mobilization and phosphodiesterase inhibition. However, a normal physiological dose of caffeine in vivo does not indicate this mechanism plays a

  6. Mood and psychomotor performance effects of the first, but not of subsequent, cup-of-coffee equivalent doses of caffeine consumed after overnight caffeine abstinence.

    PubMed

    Robelin, M; Rogers, P J

    1998-11-01

    Moderate caffeine consumers (n = 64, mean caffeine intake 453 mg/day) were deprived of caffeine overnight and semi-randomly allocated to four treatment groups, designated PPP, CPP, CCP and CCC, where P is placebo and C is caffeine (1.2 mg/kg, giving an amount of caffeine similar to that consumed in a serving of ground coffee). Caffeine or placebo (i.e. no caffeine) were administered double-blind in novel fruit juice drinks at 10:15, 11:30 and 13:00 h on the test day. Before (baseline), and 45 min after each of these times the participants completed a mood questionnaire and begun psychomotor performance tests lasting 25 min (1-min tapping task, and a long-duration simple reaction time task (SRT). Caffeine significantly increased energetic mood and improved psychomotor performance relative to placebo. Caffeine had particularly marked effects on SRT performance, ameliorating the slowing of performance with time on task and removing the post-lunch dip in performance. However, the three caffeine treatments, CPP, CCP and CCC, were equally effective. That is, mood and performance were improved to the same extent by one, two and three spaced doses (totalling 86, 172 and 258 mg) of caffeine. This result is consistent with previous findings indicating a flat dose-response relationship for the psychoactive effects of caffeine; and because of the adverse effects (e.g. fatigue) associated with overnight caffeine deprivation, it suggests that there is little net benefit to be gained from frequent caffeine use. At the very least, it appears that the psychostimulant effects of caffeine cannot on their own account for the typical pattern of consumption of caffeine-containing drinks.

  7. Active thermography and post-processing image enhancement for recovering of abraded and paint-covered alphanumeric identification marks

    NASA Astrophysics Data System (ADS)

    Montanini, R.; Quattrocchi, A.; Piccolo, S. A.

    2016-09-01

    Alphanumeric marking is a common technique employed in industrial applications for identification of products. However, the realised mark can undergo deterioration, either by extensive use or voluntary deletion (e.g. removal of identification numbers of weapons or vehicles). For recovery of the lost data many destructive or non-destructive techniques have been endeavoured so far, which however present several restrictions. In this paper, active infrared thermography has been exploited for the first time in order to assess its effectiveness in restoring paint covered and abraded labels made by means of different manufacturing processes (laser, dot peen, impact, cold press and scribe). Optical excitation of the target surface has been achieved using pulse (PT), lock-in (LT) and step heating (SHT) thermography. Raw infrared images were analysed with a dedicated image processing software originally developed in Matlab™, exploiting several methods, which include thermographic signal reconstruction (TSR), guided filtering (GF), block guided filtering (BGF) and logarithmic transformation (LN). Proper image processing of the raw infrared images resulted in superior contrast and enhanced readability. In particular, for deeply abraded marks, good outcomes have been obtained by application of logarithmic transformation to raw PT images and block guided filtering to raw phase LT images. With PT and LT it was relatively easy to recover labels covered by paint, with the latter one providing better thermal contrast for all the examined targets. Step heating thermography never led to adequate label identification instead.

  8. A hypothalamic-pituitary-adrenal axis-associated neuroendocrine metabolic programmed alteration in offspring rats of IUGR induced by prenatal caffeine ingestion.

    PubMed

    Xu, D; Wu, Y; Liu, F; Liu, Y S; Shen, L; Lei, Y Y; Liu, J; Ping, J; Qin, J; Zhang, C; Chen, L B; Magdalou, J; Wang, H

    2012-11-01

    Caffeine is a definite factor of intrauterine growth retardation (IUGR). Previously, we have confirmed that prenatal caffeine ingestion inhibits the development of hypothalamic-pituitary-adrenal (HPA) axis, and alters the glucose and lipid metabolism in IUGR fetal rats. In this study, we aimed to verify a programmed alteration of neuroendocrine metabolism in prenatal caffeine ingested-offspring rats. The results showed that prenatal caffeine (120 mg/kg.day) ingestion caused low body weight and high IUGR rate of pups; the concentrations of blood adrenocorticotropic hormone (ACTH) and corticosterone in caffeine group were significantly increased in the early postnatal period followed by falling in late stage; the level of blood glucose was unchanged, while blood total cholesterol (TCH) and triglyceride (TG) were markedly enhanced in adult. After chronic stress, the concentrations and the gain rates of blood ACTH and corticosterone were obviously increased, meanwhile, the blood glucose increased while the TCH and TG decreased in caffeine group. Further, the hippocampal mineralocorticoid receptor (MR) expression in caffeine group was initially decreased and subsequently increased after birth. After chronic stress, the 11β-hydroxysteroid dehydrogenase-1, glucocorticoid receptor (GR), MR as well as the MR/GR ratio were all significantly decreased. These results suggested that prenatal caffeine ingestion induced the dysfunction of HPA axis and associated neuroendocrine metabolic programmed alteration in IUGR offspring rats, which might be related with the functional injury of hippocampus. These observations provide a valuable experimental basis for explaining the susceptibility of IUGR offspring to metabolic syndrome and associated diseases. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Markedly enhanced absorption and direct radiative forcing of black carbon under polluted urban environments

    NASA Astrophysics Data System (ADS)

    Peng, Jianfei; Hu, Min; Guo, Song; Du, Zhuofei; Zheng, Jing; Shang, Dongjie; Levy Zamora, Misti; Zeng, Limin; Shao, Min; Wu, Yu-Sheng; Zheng, Jun; Wang, Yuan; Glen, Crystal R.; Collins, Donald R.; Molina, Mario J.

    2016-04-01

    Black carbon (BC) exerts profound impacts on air quality and climate because of its high absorption cross-section over a broad range of electromagnetic spectra, but the current results on absorption enhancement of BC particles during atmospheric aging remain conflicting. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China, and Houston, United States, using a novel environmental chamber approach. BC aging exhibits two distinct stages, i.e., initial transformation from a fractal to spherical morphology with little absorption variation and subsequent growth of fully compact particles with a large absorption enhancement. The timescales to achieve complete morphology modification and an absorption amplification factor of 2.4 for BC particles are estimated to be 2.3 h and 4.6 h, respectively, in Beijing, compared with 9 h and 18 h, respectively, in Houston. Our findings indicate that BC under polluted urban environments could play an essential role in pollution development and contribute importantly to large positive radiative forcing. The variation in direct radiative forcing is dependent on the rate and timescale of BC aging, with a clear distinction between urban cities in developed and developing countries, i.e., a higher climatic impact in more polluted environments. We suggest that mediation in BC emissions achieves a cobenefit in simultaneously controlling air pollution and protecting climate, especially for developing countries.

  10. Markedly enhanced absorption and direct radiative forcing of black carbon under polluted urban environments

    PubMed Central

    Peng, Jianfei; Hu, Min; Guo, Song; Du, Zhuofei; Zheng, Jing; Shang, Dongjie; Levy Zamora, Misti; Zeng, Limin; Shao, Min; Wu, Yu-Sheng; Zheng, Jun; Wang, Yuan; Glen, Crystal R.; Collins, Donald R.; Molina, Mario J.; Zhang, Renyi

    2016-01-01

    Black carbon (BC) exerts profound impacts on air quality and climate because of its high absorption cross-section over a broad range of electromagnetic spectra, but the current results on absorption enhancement of BC particles during atmospheric aging remain conflicting. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China, and Houston, United States, using a novel environmental chamber approach. BC aging exhibits two distinct stages, i.e., initial transformation from a fractal to spherical morphology with little absorption variation and subsequent growth of fully compact particles with a large absorption enhancement. The timescales to achieve complete morphology modification and an absorption amplification factor of 2.4 for BC particles are estimated to be 2.3 h and 4.6 h, respectively, in Beijing, compared with 9 h and 18 h, respectively, in Houston. Our findings indicate that BC under polluted urban environments could play an essential role in pollution development and contribute importantly to large positive radiative forcing. The variation in direct radiative forcing is dependent on the rate and timescale of BC aging, with a clear distinction between urban cities in developed and developing countries, i.e., a higher climatic impact in more polluted environments. We suggest that mediation in BC emissions achieves a cobenefit in simultaneously controlling air pollution and protecting climate, especially for developing countries. PMID:27035993

  11. Markedly enhanced absorption and direct radiative forcing of black carbon under polluted urban environments.

    PubMed

    Peng, Jianfei; Hu, Min; Guo, Song; Du, Zhuofei; Zheng, Jing; Shang, Dongjie; Levy Zamora, Misti; Zeng, Limin; Shao, Min; Wu, Yu-Sheng; Zheng, Jun; Wang, Yuan; Glen, Crystal R; Collins, Donald R; Molina, Mario J; Zhang, Renyi

    2016-04-19

    Black carbon (BC) exerts profound impacts on air quality and climate because of its high absorption cross-section over a broad range of electromagnetic spectra, but the current results on absorption enhancement of BC particles during atmospheric aging remain conflicting. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China, and Houston, United States, using a novel environmental chamber approach. BC aging exhibits two distinct stages, i.e., initial transformation from a fractal to spherical morphology with little absorption variation and subsequent growth of fully compact particles with a large absorption enhancement. The timescales to achieve complete morphology modification and an absorption amplification factor of 2.4 for BC particles are estimated to be 2.3 h and 4.6 h, respectively, in Beijing, compared with 9 h and 18 h, respectively, in Houston. Our findings indicate that BC under polluted urban environments could play an essential role in pollution development and contribute importantly to large positive radiative forcing. The variation in direct radiative forcing is dependent on the rate and timescale of BC aging, with a clear distinction between urban cities in developed and developing countries, i.e., a higher climatic impact in more polluted environments. We suggest that mediation in BC emissions achieves a cobenefit in simultaneously controlling air pollution and protecting climate, especially for developing countries.

  12. Selected C8 two-chain linkers enhance the adenosine A1/A2A receptor affinity and selectivity of caffeine.

    PubMed

    van der Walt, M M; Terre'Blanche, G

    2017-01-05

    Recent research exploring C8 substitution on the caffeine core identified 8-(2-phenylethyl)-1,3,7-trimethylxanthine as a non-selective adenosine receptor antagonist. To elaborate further, we included various C8 two-chain-length linkers to enhance adenosine receptor affinity. The results indicated that the unsubstituted benzyloxy linker (1e A1Ki = 1.52 μM) displayed the highest affinity for the A1 adenosine receptor and the para-chloro-substituted phenoxymethyl (1d A2AKi = 1.33 μM) linker the best A2A adenosine receptor affinity. The position of the oxygen revealed that the phenoxymethyl linker favoured A1 adenosine receptor selectivity over the benzyloxy linker and, by introducing a para-chloro substituent, A2A adenosine receptor selectivity was obtained. Selected compounds (1c, 1e) behaved as A1 adenosine receptor antagonists in GTP shift assays and therefore represent selective and non-selective A1 and A2A adenosine receptor antagonists that may have potential for treating neurological disorders.

  13. Markedly enhanced direct radiative forcing of black carbon particles under polluted urban environments

    NASA Astrophysics Data System (ADS)

    Peng, Jianfei; Hu, Min; Guo, Song; Du, Zhuofei; Zheng, Jing; Shang, Dongjie; Zamora, Misti; Zeng, Liming; Shao, Min; Wu, Yusheng; Zheng, Jun; Wang, Yuan; Collins, Don; Zhang, Renyi

    2016-04-01

    Black carbon (BC) particles, produced from incomplete fossil fuel combustion and biomass burning, are ubiquitous in the atmosphere and have profound impacts on air quality, human health, weather, and climate. For example, in areas identified as aerosol hotspots, which include many urban centers and megacities worldwide, solar heating by BC particles has been shown to be comparable to warming due to the greenhouse gases2. Although BC represents a key short-lived climate forcer, its direct radiative forcing remains highly uncertain. In particular, the available results of absorption enhancement of BC particles during atmospheric aging are conflicting from the previous studies, leading to a large uncertainty in global radiative transfer calculation. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China and Houston, US, using a novel chamber approach. BC aging exhibits two distinct stages - initial transformation from a fractal to spherical morphology with little absorption variation and the subsequent growth of fully compact particles with a maximum absorption enhancement factor of 2.4. The variation in BC direct radiative forcing is highly dependent of the rate and timescale of aging, with an estimated increase of 0.45 (0.21 - 0.80) W m-2 from fresh to fully aged particles. Our results reveal a high climatic impact in polluted environments due to rapid aging and a clear distinction between urban cities in developed and developing countries for BC particles, highlighting a larger than recognized co-benefit in air quality improvement and climate protection by BC mediation.

  14. Mucosal stromal fibroblasts markedly enhance HIV infection of CD4+ T cells

    PubMed Central

    Kohgadai, Nargis; Müller, Janis A.; Laustsen, Anders; Thavachelvam, Karthiga; Stürzel, Christina M.; Jones, Jennifer J.; Somsouk, Ma; Garcia, Maurice M.; Smith, James F.; Greenblatt, Ruth M.; Münch, Jan; Jakobsen, Martin R.; Giudice, Linda C.; Greene, Warner C.; Roan, Nadia R.

    2017-01-01

    Understanding early events of HIV transmission within mucosal tissues is vital for developing effective prevention strategies. Here, we report that primary stromal fibroblasts isolated from endometrium, cervix, foreskin, male urethra, and intestines significantly increase HIV infection of CD4+ T cells–by up to 37-fold for R5-tropic HIV and 100-fold for X4-tropic HIV–without themselves becoming infected. Fibroblasts were more efficient than dendritic cells at trans-infection and mediate this response in the absence of the DC-SIGN and Siglec-1 receptors. In comparison, mucosal epithelial cells secrete antivirals and inhibit HIV infection. These data suggest that breaches in the epithelium allow external or luminal HIV to escape an antiviral environment to access the infection-favorable environment of the stromal fibroblasts, and suggest that resident fibroblasts have a central, but previously unrecognized, role in HIV acquisition at mucosal sites. Inhibiting fibroblast-mediated enhancement of HIV infection should be considered as a novel prevention strategy. PMID:28207890

  15. Caffeinated energy drinks in children.

    PubMed

    Goldman, Ran D

    2013-09-01

    A 14-year-old boy came to my office to discuss his frequent consumption of energy drinks to enhance his performance at school and while playing soccer. What is the recommended use of energy drinks in children and is there any harm in consuming them? Energy drinks are beverages with a high concentration of caffeine and additional stimulants. They are sold in numerous places and are easily accessed by children, adolescents, and young adults. Many reports warn about potential adverse effects associated with their consumption, especially in combination with alcohol among adolescents, and in combination with stimulant medications among children treated for attention deficit hyperactivity disorder. Children and adolescents should avoid energy drinks, and health care providers should educate youth and their parents about the risks of caffeinated drinks.

  16. Ergotamine and Caffeine

    MedlinePlus

    Ergotamine and caffeine may cause side effects. Tell your doctor if either of these symptoms is severe or does not go away: nausea vomiting Some ... tingling in the fingers and toes Ergotamine and caffeine may cause other side effects. Call your doctor if you have any unusual ...

  17. Caffeine and cardiac arrhythmias.

    PubMed

    Myers, M G

    1991-01-15

    To review the evidence supporting the belief that caffeine causes cardiac arrhythmias. Studies published since 1982 identified through computerized searches of MEDLINE, TOXLINE, and Chemical Abstracts and a review of bibliographies of relevant articles on the subject of caffeine and cardiac arrhythmias. All clinical studies examining caffeine as a cause of cardiac arrhythmias and a selection of basic science experiments to illustrate caffeine's effects in vitro. Study quality was assessed and all available clinical data pertaining to caffeine as a cause of arrhythmias were summarized. In one electrophysiologic study, caffeine was associated with an increased susceptibility to provoked cardiac arrhythmias. In five placebo-controlled trials, caffeine in doses up to 500 mg daily (equivalent to 5 to 6 cups of coffee) did not increase the frequency or severity of ventricular arrhythmias. One large epidemiologic study reported an increase in the frequency of ventricular extrasystoles in persons consuming 9 or more cups of coffee daily. Moderate ingestion of caffeine does not increase the frequency or severity of cardiac arrhythmias in normal persons, patients with ischemic heart disease, or those with pre-existing serious ventricular ectopy.

  18. International society of sports nutrition position stand: caffeine and performance

    PubMed Central

    2010-01-01

    Position Statement: The position of The Society regarding caffeine supplementation and sport performance is summarized by the following seven points: 1.) Caffeine is effective for enhancing sport performance in trained athletes when consumed in low-to-moderate dosages (~3-6 mg/kg) and overall does not result in further enhancement in performance when consumed in higher dosages (≥ 9 mg/kg). 2.) Caffeine exerts a greater ergogenic effect when consumed in an anhydrous state as compared to coffee. 3.) It has been shown that caffeine can enhance vigilance during bouts of extended exhaustive exercise, as well as periods of sustained sleep deprivation. 4.) Caffeine is ergogenic for sustained maximal endurance exercise, and has been shown to be highly effective for time-trial performance. 5.) Caffeine supplementation is beneficial for high-intensity exercise, including team sports such as soccer and rugby, both of which are categorized by intermittent activity within a period of prolonged duration. 6.) The literature is equivocal when considering the effects of caffeine supplementation on strength-power performance, and additional research in this area is warranted. 7.) The scientific literature does not support caffeine-induced diuresis during exercise, or any harmful change in fluid balance that would negatively affect performance. PMID:20205813

  19. International society of sports nutrition position stand: caffeine and performance.

    PubMed

    Goldstein, Erica R; Ziegenfuss, Tim; Kalman, Doug; Kreider, Richard; Campbell, Bill; Wilborn, Colin; Taylor, Lem; Willoughby, Darryn; Stout, Jeff; Graves, B Sue; Wildman, Robert; Ivy, John L; Spano, Marie; Smith, Abbie E; Antonio, Jose

    2010-01-27

    Position Statement: The position of The Society regarding caffeine supplementation and sport performance is summarized by the following seven points: 1.) Caffeine is effective for enhancing sport performance in trained athletes when consumed in low-to-moderate dosages (~3-6 mg/kg) and overall does not result in further enhancement in performance when consumed in higher dosages (>/= 9 mg/kg). 2.) Caffeine exerts a greater ergogenic effect when consumed in an anhydrous state as compared to coffee. 3.) It has been shown that caffeine can enhance vigilance during bouts of extended exhaustive exercise, as well as periods of sustained sleep deprivation. 4.) Caffeine is ergogenic for sustained maximal endurance exercise, and has been shown to be highly effective for time-trial performance. 5.) Caffeine supplementation is beneficial for high-intensity exercise, including team sports such as soccer and rugby, both of which are categorized by intermittent activity within a period of prolonged duration. 6.) The literature is equivocal when considering the effects of caffeine supplementation on strength-power performance, and additional research in this area is warranted. 7.) The scientific literature does not support caffeine-induced diuresis during exercise, or any harmful change in fluid balance that would negatively affect performance.

  20. Exercise and sport performance with low doses of caffeine.

    PubMed

    Spriet, Lawrence L

    2014-11-01

    Caffeine is a popular work-enhancing supplement that has been actively researched since the 1970s. The majority of research has examined the effects of moderate to high caffeine doses (5-13 mg/kg body mass) on exercise and sport. These caffeine doses have profound effects on the responses to exercise at the whole-body level and are associated with variable results and some undesirable side effects. Low doses of caffeine (<3 mg/kg body mass, ~200 mg) are also ergogenic in some exercise and sport situations, although this has been less well studied. Lower caffeine doses (1) do not alter the peripheral whole-body responses to exercise; (2) improve vigilance, alertness, and mood and cognitive processes during and after exercise; and (3) are associated with few, if any, side effects. Therefore, the ergogenic effect of low caffeine doses appears to result from alterations in the central nervous system. However, several aspects of consuming low doses of caffeine remain unresolved and suffer from a paucity of research, including the potential effects on high-intensity sprint and burst activities. The responses to low doses of caffeine are also variable and athletes need to determine whether the ingestion of ~200 mg of caffeine before and/or during training and competitions is ergogenic on an individual basis.

  1. Caffeine for asthma.

    PubMed

    Welsh, Emma J; Bara, Anna; Barley, Elizabeth; Cates, Christopher J

    2010-01-20

    Caffeine has a variety of pharmacological effects; it is a weak bronchodilator and it also reduces respiratory muscle fatigue. It is chemically related to the drug theophylline which is used to treat asthma. It has been suggested that caffeine may reduce asthma symptoms and interest has been expressed in its potential role as an asthma treatment. A number of studies have explored the effects of caffeine in asthma, this is the first review to systematically examine and summarise the evidence. To assess the effects of caffeine on lung function and identify whether there is a need to control for caffeine consumption prior to either lung function or exhaled nitric oxide testing. We searched the Cochrane Airways Group trials register and the reference lists of articles (August 2009). We also contacted study authors. Randomised clinical trials of oral caffeine compared to placebo or coffee compared to decaffeinated coffee in adults with asthma. Trial selection, quality assessment and data extraction were done independently by two reviewers. Seven trials involving a total of 75 people with mild to moderate asthma were included. The studies were all of cross-over design .Six trials involving 55 people showed that in comparison with placebo, caffeine, even at a 'low dose' (< 5mg/kg body weight), appears to improve lung function for up to two hours after consumption. Forced expiratory volume in one minute showed a small improvement up to two hours after caffeine ingestion (SMD 0.72; 95% CI 0.25 to 1.20), which translates into a 5% mean difference in FEV1. However in two studies the mean differences in FEV1 were 12% and 18% after caffeine. Mid-expiratory flow rates also showed a small improvement with caffeine and this was sustained up to four hours.One trial involving 20 people examined the effect of drinking coffee versus a decaffeinated variety on the exhaled nitric oxide levels in patients with asthma and concluded that there was no significant effect on this outcome

  2. Caffeine induces CYP1A2 expression in rat hepatocytes but not in human hepatocytes.

    PubMed

    Vaynshteyn, David; Jeong, Hyunyoung

    2012-06-01

    Caffeine is the active constituent in coffee. Continual consumption of caffeine can lead to an attenuated response also known as tolerance. Results from rat studies have shown that caffeine is an inducer of CYP1A2, the enzyme responsible for caffeine's metabolism. This suggests that CYP1A2 induction by caffeine may be in part responsible for caffeine tolerance. However, whether caffeine induces CYP1A2 expression in humans remains unknown. Our results from luciferase assays performed in HepG2 cells showed that caffeine is not an activator of the aromatic hydrocarbon receptor (AhR), a major transcription factor involved in upregulation of CYP1A2. Furthermore, caffeine did not induce CYP1A2 expression in primary human hepatocytes at a concentration attained by ordinary coffee drinking. On the other hand, caffeine enhanced CYP1A2 expression by 9-fold in rat hepatocytes. Our results suggest that caffeine from ordinary coffee drinking does not induce CYP1A2 expression in humans and that factors other than CYP1A2 induction by caffeine likely contribute to development of caffeine tolerance in humans.

  3. Spectrophotometric Analysis of Caffeine

    PubMed Central

    Ahmad Bhawani, Showkat; Fong, Sim Siong; Mohamad Ibrahim, Mohamad Nasir

    2015-01-01

    The nature of caffeine reveals that it is a bitter white crystalline alkaloid. It is a common ingredient in a variety of drinks (soft and energy drinks) and is also used in combination with various medicines. In order to maintain the optimum level of caffeine, various spectrophotometric methods have been developed. The monitoring of caffeine is very important aspect because of its consumption in higher doses that can lead to various physiological disorders. This paper incorporates various spectrophotometric methods used in the analysis of caffeine in various environmental samples such as pharmaceuticals, soft and energy drinks, tea, and coffee. A range of spectrophotometric methodologies including chemometric techniques and derivatization of spectra have been used to analyse the caffeine. PMID:26604926

  4. Spectrophotometric Analysis of Caffeine.

    PubMed

    Ahmad Bhawani, Showkat; Fong, Sim Siong; Mohamad Ibrahim, Mohamad Nasir

    2015-01-01

    The nature of caffeine reveals that it is a bitter white crystalline alkaloid. It is a common ingredient in a variety of drinks (soft and energy drinks) and is also used in combination with various medicines. In order to maintain the optimum level of caffeine, various spectrophotometric methods have been developed. The monitoring of caffeine is very important aspect because of its consumption in higher doses that can lead to various physiological disorders. This paper incorporates various spectrophotometric methods used in the analysis of caffeine in various environmental samples such as pharmaceuticals, soft and energy drinks, tea, and coffee. A range of spectrophotometric methodologies including chemometric techniques and derivatization of spectra have been used to analyse the caffeine.

  5. Understanding adolescent caffeine use: connecting use patterns with expectancies, reasons, and sleep.

    PubMed

    Bryant Ludden, Alison; Wolfson, Amy R

    2010-06-01

    Little is known about adolescents' caffeine use, yet caffeinated soda, and more recently coffee and energy drinks, are part of youth culture. This study examines adolescents' caffeine use and, using cluster analysis, identifies three groups of caffeine users who differed in their reasons for use, expectancies, and sleep behaviors. In this high school student sample (N = 197), 95% of participants reported recent caffeine use-most often soda-where typical first use of the day was in the evening. Results reveal that adolescents in the mixed use and high soda use groups consumed similar amounts of soda, reporting significantly more use than the low caffeine use group. In contrast with high soda users, mixed users drank more coffee, expected more dependence symptoms and energy enhancement from caffeine, and were more likely to report getting up early, daytime sleepiness, and using caffeine to get through the day.

  6. Caffeine Positively Modulates Ferritin Heavy Chain Expression in H460 Cells: Effects on Cell Proliferation.

    PubMed

    Zolea, Fabiana; Biamonte, Flavia; Battaglia, Anna Martina; Faniello, Maria Concetta; Cuda, Giovanni; Costanzo, Francesco

    Both the methylxanthine caffeine and the heavy subunit of ferritin molecule (FHC) are able to control the proliferation rate of several cancer cell lines. While caffeine acts exclusively as a negative modulator of cell proliferation, FHC might reduce or enhance cell viability depending upon the different cell type. In this work we have demonstrated that physiological concentrations of caffeine reduce the proliferation rate of H460 cells: along with the modulation of p53, pAKT and Cyclin D1, caffeine also determines a significant FHC up-regulation through the activation of its transcriptional efficiency. FHC plays a central role in the molecular pathways modulated by caffeine, ending in a reduced cell growth, since its specific silencing by siRNA almost completely abolishes caffeine effects on H460 cell proliferation. These results allow the inclusion of ferritin heavy subunits among the multiple molecular targets of caffeine and open the way for studying the relationship between caffeine and intracellular iron metabolism.

  7. Caffeine use: is there a net benefit for mood and psychomotor performance?

    PubMed

    Rogers, P J; Richardson, N J; Dernoncourt, C

    1995-01-01

    We agree with the conclusions of a recent article in this journal [James, Neuropsychobiology 1994;30:124-125] that studies on the psychoactive effects of caffeine need to take into account the possibility that the results obtained might represent merely the reversal of deleterious effects of caffeine deprivation rather than an actual net benefit due to caffeine use. However, in a review of recent studies we find no unequivocal evidence of impaired psychomotor performance associated with caffeine withdrawal. This is in contrast to a clear deterioration of mood which occurs even after overnight caffeine deprivation. We concluded that current evidence points to true performance-enhancing effects of caffeine, although the extent of these and the conditions under which caffeine is most effective have yet to be fully determined. At the same time, the existence of significant detrimental effects of caffeine deprivation on psychomotor performance has not been ruled out.

  8. Caffeine dimerization: effects of sugar, salts, and water structure.

    PubMed

    Shimizu, Seishi

    2015-10-01

    Sugars and salts strongly affect the dimerization of caffeine in water. Such a change of dimerization, considered to be crucial for bitter taste suppression, has long been rationalized by the change of "water structure" induced by the additives; "kosmotropic" (water structure enhancing) salts and sugars promote dimerization, whereas "chaotropic" (water structure breaking) salts suppress dimerization. Based on statistical thermodynamics, here we challenge this consensus; we combine the rigorous Kirkwood-Buff theory of solution with the classical isodesmic model of caffeine association. Instead of the change of water structure, we show that the enhancement of caffeine dimerization is due to the exclusion of additives from caffeine, and that the weakening of dimerization is due to the binding of additives on caffeine.

  9. Drosophila enhancer of Zeste/ESC complexes have a histone H3 methyltransferase activity that marks chromosomal Polycomb sites.

    PubMed

    Czermin, Birgit; Melfi, Raffaella; McCabe, Donna; Seitz, Volker; Imhof, Axel; Pirrotta, Vincenzo

    2002-10-18

    Enhancer of Zeste is a Polycomb Group protein essential for the establishment and maintenance of repression of homeotic and other genes. In the early embryo it is found in a complex that includes ESC and is recruited to Polycomb Response Elements. We show that this complex contains a methyltransferase activity that methylates lysine 9 and lysine 27 of histone H3, but the activity is lost when the E(Z) SET domain is mutated. The lysine 9 position is trimethylated and this mark is closely associated with Polycomb binding sites on polytene chromosomes but is also found in centric heterochromatin, chromosome 4, and telomeric sites. Histone H3 methylated in vitro by the E(Z)/ESC complex binds specifically to Polycomb protein.

  10. Caffeine Toxicity Due to Supplement Use in Caffeine--Naïve Individual: A Cautionary Tale.

    PubMed

    Lystrup, Robert M; Leggit, Jeffery C

    2015-08-01

    Thousands of military members self-medicate with dietary supplements containing unknown quantities of pharmacologically active compounds. These poorly regulated substances can cause real harm to the military population, especially when they contain stimulants such as caffeine. When taken regularly, caffeine has several performance-enhancing benefits. However, when used excessively or in vulnerable populations, caffeine can cause several unwanted side effects such as nervousness, sensory disturbances, insomnia, arrhythmia, excitability, inattentiveness, restlessness, mood changes, gastrointestinal disturbances, and even psychosis. Vulnerable patients include the caffeine-naïve, physiologically stressed, young, and mentally ill patients. One such case describes a caffeine-naïve service member who suffered an adverse reaction after taking an allegedly moderate dose of caffeine from a pill he obtained from a teammate. This case highlights the importance of supplement awareness among service members, increased provider vigilance, third party verification, and enhanced regulation on the approval and marketing of dietary supplements. Reprint & Copyright © 2015 Association of Military Surgeons of the U.S.

  11. H3.3 actively marks enhancers and primes gene transcription via opening higher-ordered chromatin.

    PubMed

    Chen, Ping; Zhao, Jicheng; Wang, Yan; Wang, Min; Long, Haizhen; Liang, Dan; Huang, Li; Wen, Zengqi; Li, Wei; Li, Xia; Feng, Hongli; Zhao, Haiyong; Zhu, Ping; Li, Ming; Wang, Qian-fei; Li, Guohong

    2013-10-01

    The histone variants H3.3 and H2A.Z have recently emerged as two of the most important features in transcriptional regulation, the molecular mechanism of which still remains poorly understood. In this study, we investigated the regulation of H3.3 and H2A.Z on chromatin dynamics during transcriptional activation. Our in vitro biophysical and biochemical investigation showed that H2A.Z promoted chromatin compaction and repressed transcriptional activity. Surprisingly, with only four to five amino acid differences from the canonical H3, H3.3 greatly impaired higher-ordered chromatin folding and promoted gene activation, although it has no significant effect on the stability of mononucleosomes. We further demonstrated that H3.3 actively marks enhancers and determines the transcriptional potential of retinoid acid (RA)-regulated genes via creating an open chromatin signature that enables the binding of RAR/RXR. Additionally, the H3.3-dependent recruitment of H2A.Z on promoter regions resulted in compaction of chromatin to poise transcription, while RA induction results in the incorporation of H3.3 on promoter regions to activate transcription via counteracting H2A.Z-mediated chromatin compaction. Our results provide key insights into the mechanism of how histone variants H3.3 and H2A.Z function together to regulate gene transcription via the modulation of chromatin dynamics over the enhancer and promoter regions.

  12. Caffeine at work.

    PubMed

    Smith, Andrew P

    2005-08-01

    There is a large literature on the effects of caffeine on performance. Most of the studies have been conducted in the laboratory and further information is required on the effects of caffeine consumption on performance and safety at work. The present studies aimed to determine whether the level of caffeine consumption influenced changes in alertness and performance over the working day. Secondary analyses of a large epidemiological database were also conducted to examine associations between caffeine consumption and cognitive failures and accidents at work. In the first study 110 volunteers, all of whom were regular caffeine consumers, rated their alertness and carried out a simple reaction time task before and after work on a Monday and Friday. Caffeine consumption during the day was recorded and volunteers were sub-divided into low and high consumers on the basis of a median split (220 mg/day). The second study involved secondary analyses of a database formed by combining the Bristol Stress and Health at Work and Cardiff Health and Safety at Work studies. In the first analyses associations between caffeine consumption and frequency of cognitive failures were examined in a sample of 1253 white-collar workers. The second set of analyses examined associations between caffeine consumption and accidents at work in a sample of 1555 workers who were especially at risk of having an accident. The results from the first study showed that those who consumed higher levels of caffeine reported significantly greater increases in alertness over the working day and a significantly smaller slowing of reaction time. The results from the second study demonstrated significant associations between caffeine consumption and fewer cognitive failures and accidents at work. After controlling for possible confounding factors it was found that higher caffeine consumption was associated with about half the risk of frequent/very frequent cognitive failures and a similar reduction in risk for

  13. Enhanced antigen-presenting capacity of cultured Langerhans' cells is associated with markedly increased expression of Ia antigen

    SciTech Connect

    Shimada, S.; Caughman, S.W.; Sharrow, S.O.; Stephany, D.; Katz, S.I.

    1987-10-15

    Recent studies indicate that when epidermal Langerhans' cells (LC) are cultured for 2 to 3 days they, in comparison to freshly prepared LC, exhibit markedly enhanced ability to stimulate T cell proliferative responses in oxidative mitogenesis and in the mixed epidermal-leukocyte reaction. In this study, we determined whether cultured LC enhance antigen-specific T cell responses, and whether such enhanced stimulatory capacity correlates with the level of Ia antigen expressed on LC. We used C3H/He (Iak) epidermal cells as stimulators and, as responder cells, both the trinitrophenyl-specific clones D8 and SE4, which were assayed for (/sup 3/H)dThd incorporation, and the pigeon cytochrome c specific hybridoma 2C2, which was assayed for interleukin 2 production. Cultured LC induced 10 to 100 times greater proliferation or interleukin 2 production by responder cells than did freshly prepared LC. The intensity of I-Ak and I-Ek, expressed on cultured LC as assessed by immunofluorescence and flow cytometry, was found to be 10 to 36 times greater on a per cell basis than that on freshly prepared LC. Depletion of LC from fresh epidermal cell suspensions by anti-Iak and complement or treatment with 50 mJ/cm/sup 2/ medium range ultraviolet light or cycloheximide before culture abrogated both the increase in Ia expression and antigen-specific clonal proliferation. The results suggest that when LC are removed from their usual epidermal milieu, they express increased amounts of Ia and become more potent stimulators of T cell responses.

  14. Caffeine augments Alprazolam induced cytotoxicity in human cell lines.

    PubMed

    Saha, Biswarup; Mukherjee, Ananda; Samanta, Saheli; Saha, Piyali; Ghosh, Anup Kumar; Santra, Chitta Ranjan; Karmakar, Parimal

    2009-09-01

    Combined effects of alprazolam (Alp), a member of benzodiazepine group of drugs and caffeine on human cell lines, HeLa and THP1 were investigated in this study. Alp mediated cytotoxicity was enhanced while caffeine was present. The cell death was confirmed by observing morphological changes, LDH assay and membrane anisotropic study. Also such combined effects induced elevated level of ROS and depletion of GSH. The mechanism of cell death induced by simultaneous treatment of Alp and caffeine was associated with the calcium-mediated activation of mu-calpain, release of lysosomal protease cathepsin B, activation of PARP and cleavage of caspase 3. Our results indicate that, Alp alone induces apoptosis in human cells but in the presence of caffeine it augments necrosis in a well-regulated pathway. Thus our observations strongly suggest that, alprazolam and caffeine together produce severe cytotoxicity in human cell lines.

  15. Caffeine improves anticipatory processes in task switching.

    PubMed

    Tieges, Zoë; Snel, Jan; Kok, Albert; Wijnen, Jasper G; Lorist, Monicque M; Richard Ridderinkhof, K

    2006-08-01

    We studied the effects of moderate amounts of caffeine on task switching and task maintenance using mixed-task (AABB) blocks, in which participants alternated predictably between two tasks, and single-task (AAAA, BBBB) blocks. Switch costs refer to longer reaction times (RT) on task switch trials (e.g. AB) compared to task-repeat trials (e.g. BB); mixing costs refer to longer RTs in task-repeat trials compared to single-task trials. In a double-blind, within-subjects experiment, two caffeine doses (3 and 5mg/kg body weight) and a placebo were administered to 18 coffee drinkers. Both caffeine doses reduced switch costs compared to placebo. Event-related brain potentials revealed a negative deflection developing within the preparatory interval, which was larger for switch than for repeat trials. Caffeine increased this switch-related difference. These results suggest that coffee consumption improves task-switching performance by enhancing anticipatory processing such as task set updating, presumably through the neurochemical effects of caffeine on the dopamine system.

  16. Luminescence characteristics of caffeine and theophylline1

    NASA Astrophysics Data System (ADS)

    Andino, M. M.; De Lima, C. G.; Winefordner, J. D.

    The luminescence properties of solutions of caffeine and theophylline in methanol are observed. The effects of the solvent pH, the presence of a heavy atom and the matrix or substrate on the fluorescence and phosphorescence properties of the compounds are evaluated. Caffeine and theophylline fluorescence can be observed at room temperature from dilute methanolic solutions and strong phosphorescence is observed at low temperature when the matrix is in a polycrystalline state. Acidic and basic media cause spectral changes and reduce the intensity of the low temperature phosphorescence. Iodide is a good heavy-atom enhancer of both the low temperature and room temperature phosphorescence of caffeine and theophylline. The intensity of the phosphorescence at room temperature and when spotted on filter paper depends on the type of filter paper and the pH of the spotting solution and/or the pH of the wet surface at the moment of spotting. Theophylline is more sensitive than caffeine to the microenvironment. Under the appropriate experimental conditions, both low temperature and room temperature phosphorescence could be used as analytical tools for the determination of caffeine and theophylline.

  17. Development of tumor-specific caffeine-potentiated chemotherapy using a novel drug delivery system with Span 80 nano-vesicles.

    PubMed

    Nakata, Hiroshi; Miyazaki, Tatsuhiko; Iwasaki, Tomoyuki; Nakamura, Atsushi; Kidani, Teruki; Sakayama, Kenshi; Masumoto, Junya; Miura, Hiromasa

    2015-04-01

    In recent years, chemotherapy with caffeine has manifested potently high efficacy against osteosarcoma, although adverse effects have been observed. Recently, we developed a novel drug delivery system (DDS) with nonionic vesicles prepared from Span 80 which have promising physicochemical properties as an attractive possible alternative to commonly used liposomes. Herein, we demonstrated that tumor-specific caffeine-potentiated chemotherapy for murine osteosarcoma administered by a novel DDS with Span 80 nano-vesicles showed significant antitumor effects as well as limited adverse effects. The osteosarcoma cell line, LM8, was transplanted into C3H/HeJ mice which then were administered therapeutic agents. Ifosfamide (IFO) was employed as well as caffeine as an enhancer. Span 80 vesicles containing IFO and/or caffeine were freshly prepared. On days 0, 2 and 4, different combinations of the agents were administered to mice: IFO alone (direct i.v.), IFO vesicles (IV), IV+caffeine, IV+caffeine vesicles (CV), PBS alone vesicles (PV), and PBS alone as negative control (PBS i.v.). Then, the mice were sacrificed on day 7. Antitumor effects of the reagents were also analyzed in vitro. Moreover, fertility examination was performed. In vitro, a combination of IV+CV showed significant induction of apoptosis in the early phase. Tumor volumes in the IV+CV group were significantly reduced compared with the other groups. Histological analyses showed that the IV and IV+CV groups had significantly lower viable tumor areas. The IFO direct i.v. group showed a certain grade of renal injury as well as marked suppression of spermatogenesis, while the IV or IV+CV group showed no marked changes. The fertility test revealed that the male mice with IV+CV administration had normal fertility, and no malformations were detected in their progeny. This DDS model is of potential importance for clinical application in the therapy of metastatic osteosarcoma.

  18. Development of tumor-specific caffeine-potentiated chemotherapy using a novel drug delivery system with Span 80 nano-vesicles

    PubMed Central

    NAKATA, HIROSHI; MIYAZAKI, TATSUHIKO; IWASAKI, TOMOYUKI; NAKAMURA, ATSUSHI; KIDANI, TERUKI; SAKAYAMA, KENSHI; MASUMOTO, JUNYA; MIURA, HIROMASA

    2015-01-01

    In recent years, chemotherapy with caffeine has manifested potently high efficacy against osteosarcoma, although adverse effects have been observed. Recently, we developed a novel drug delivery system (DDS) with nonionic vesicles prepared from Span 80 which have promising physicochemical properties as an attractive possible alternative to commonly used liposomes. Herein, we demonstrated that tumor-specific caffeine-potentiated chemotherapy for murine osteosarcoma administered by a novel DDS with Span 80 nano-vesicles showed significant antitumor effects as well as limited adverse effects. The osteosarcoma cell line, LM8, was transplanted into C3H/HeJ mice which then were administered therapeutic agents. Ifosfamide (IFO) was employed as well as caffeine as an enhancer. Span 80 vesicles containing IFO and/or caffeine were freshly prepared. On days 0, 2 and 4, different combinations of the agents were administered to mice: IFO alone (direct i.v.), IFO vesicles (IV), IV + caffeine, IV + caffeine vesicles (CV), PBS alone vesicles (PV), and PBS alone as negative control (PBS i.v.). Then, the mice were sacrificed on day 7. Antitumor effects of the reagents were also analyzed in vitro. Moreover, fertility examination was performed. In vitro, a combination of IV+CV showed significant induction of apoptosis in the early phase. Tumor volumes in the IV+CV group were significantly reduced compared with the other groups. Histological analyses showed that the IV and IV+CV groups had significantly lower viable tumor areas. The IFO direct i.v. group showed a certain grade of renal injury as well as marked suppression of spermatogenesis, while the IV or IV+CV group showed no marked changes. The fertility test revealed that the male mice with IV+CV administration had normal fertility, and no malformations were detected in their progeny. This DDS model is of potential importance for clinical application in the therapy of metastatic osteosarcoma. PMID:25633802

  19. Caffeinated energy drink intoxication

    PubMed Central

    Trabulo, Daniel; Marques, Susana; Pedroso, Ermelinda

    2011-01-01

    In recent years an increasing number of different energy drinks have been introduced to provide an energy boost. They contain high levels of caffeine and other additives that act as stimulants. Several recent studies present that energy drinks could increase the risk of seizures, acid-base disorders and cardiovascular events. The authors report a 28-year-old man who was brought to the emergency room after sudden onset of tonic-clonic seizures and metabolic acidosis after drinking several cans of a caffeinated energy drink. The authors believe that this clinical picture was caused by caffeine intoxication from an energetic drink causing a syndrome of catecholamine excess. The patient was discharged within a week with no complaints and no neurological signs. Finally, recognising the features of caffeine intoxication and its potential health consequences may be especially relevant when treating younger persons who may be more likely to consume energy drinks. PMID:22714613

  20. Caffeine in the diet

    MedlinePlus

    ... although many people still believe a cup of coffee will help a person "sober-up." Caffeine may ... than 60 plants, including: Tea leaves Kola nuts Coffee Cocoa beans It is also found in processed ...

  1. Caffeine intensifies taste of certain sweeteners: role of adenosine receptor.

    PubMed

    Schiffman, S S; Diaz, C; Beeker, T G

    1986-03-01

    Caffeine, a potent antagonist of adenosine receptors, potentiates the taste of some but not all sweeteners. It significantly enhances the taste of acesulfam-K, neohesperidin dihydrochalcone, d-tryptophan, thaumatin, stevioside, and sodium saccharin. Adenosine reverses the enhancement. Caffeine has no effect on aspartame, sucrose, fructose, and calcium cyclamate. These results suggest that the inhibitory A1 adenosine receptor plays an important local role in modulating the taste intensity of certain sweeteners and that several transduction mechanisms mediate sweet taste.

  2. Genetics of caffeine consumption and responses to caffeine.

    PubMed

    Yang, Amy; Palmer, Abraham A; de Wit, Harriet

    2010-08-01

    Caffeine is widely consumed in foods and beverages and is also used for a variety of medical purposes. Despite its widespread use, relatively little is understood regarding how genetics affects consumption, acute response, or the long-term effects of caffeine. This paper reviews the literature on the genetics of caffeine from the following: (1) twin studies comparing heritability of consumption and of caffeine-related traits, including withdrawal symptoms, caffeine-induced insomnia, and anxiety, (2) association studies linking genetic polymorphisms of metabolic enzymes and target receptors to variations in caffeine response, and (3) case-control and prospective studies examining relationship between polymorphisms associated with variations in caffeine response to risks of Parkinson's and cardiovascular diseases in habitual caffeine consumers. Twin studies find the heritability of caffeine-related traits to range between 0.36 and 0.58. Analysis of polysubstance use shows that predisposition to caffeine use is highly specific to caffeine itself and shares little common disposition to use of other substances. Genome association studies link variations in adenosine and dopamine receptors to caffeine-induced anxiety and sleep disturbances. Polymorphism in the metabolic enzyme cytochrome P-450 is associated with risk of myocardial infarction in caffeine users. Modeling based on twin studies reveals that genetics plays a role in individual variability in caffeine consumption and in the direct effects of caffeine. Both pharmacodynamic and pharmacokinetic polymorphisms have been linked to variation in response to caffeine. These studies may help guide future research in the role of genetics in modulating the acute and chronic effects of caffeine.

  3. Genetics of caffeine consumption and responses to caffeine

    PubMed Central

    Yang, Amy; Palmer, Abraham A.

    2014-01-01

    Rationale Caffeine is widely consumed in foods and beverages and is also used for a variety of medical purposes. Despite its widespread use, relatively little is understood regarding how genetics affects consumption, acute response, or the long-term effects of caffeine. Objective This paper reviews the literature on the genetics of caffeine from the following: (1) twin studies comparing heritability of consumption and of caffeine-related traits, including withdrawal symptoms, caffeine-induced insomnia, and anxiety, (2) association studies linking genetic polymorphisms of metabolic enzymes and target receptors to variations in caffeine response, and (3) case-control and prospective studies examining relationship between polymorphisms associated with variations in caffeine response to risks of Parkinson’s and cardiovascular diseases in habitual caffeine consumers. Results Twin studies find the heritability of caffeine-related traits to range between 0.36 and 0.58. Analysis of poly-substance use shows that predisposition to caffeine use is highly specific to caffeine itself and shares little common disposition to use of other substances. Genome association studies link variations in adenosine and dopamine receptors to caffeine-induced anxiety and sleep disturbances. Polymorphism in the metabolic enzyme cytochrome P-450 is associated with risk of myocardial infarction in caffeine users. Conclusion Modeling based on twin studies reveals that genetics plays a role in individual variability in caffeine consumption and in the direct effects of caffeine. Both pharmacodynamic and pharmacokinetic polymorphisms have been linked to variation in response to caffeine. These studies may help guide future research in the role of genetics in modulating the acute and chronic effects of caffeine. PMID:20532872

  4. Cardiotoxicity of Ma Huang/Caffeine or Ephedrine/Caffeine in a Rodent Model System

    PubMed Central

    Dunnick, J. K.; Kissling, G.; Gerken, D. K.; Vallant, M. A.; Nyska, A.

    2007-01-01

    Ma Huang (equivalent to 0, 12.5, 25, or 50 mg/kg ephedrine) or ephedrine (0, 6.25, 12.5, 25 mg/kg) were administered as one bolus oral dose to male F344 rats with and without caffeine. The herbal medicine Ma Huang (ephedra) in combination with caffeine caused rapid clinical signs of toxicity including salivation, hyperactivity, ataxia, and eventually lethargy, and failure to respond to stimuli. When this syndrome of clinical signs emerged, animals were moribund sacrificed, and a histological analysis for heart lesions performed. Cardiotoxicity included hemorrhage, necrosis, and degeneration in the ventricles or interventricular septum within 2–4 hours after treatment with Ma Huang (ephedra)/caffeine or ephedrine (the principal active component in Ma Huang)/caffeine. There was a steep dose response curve for cardiotoxicity with minimal toxicity seen at levels of Ma Huang (equivalent to 12.5 mg/kg ephedrine) with caffeine. However, cardiotoxic lesions occurred in 28% of animals with Ma Huang dosages equivalent to 25 mg/kg ephedrine with 15 or 30 mg/kg caffeine, and in 90% of animals at Ma Huang exposures equivalent to 50 mg/kg ephedrine with 15 or 30 mg/kg caffeine. Cardiotoxic lesions occurred in 47% of animals in the 25 mg/kg ephedrine groups with caffeine at 7.25, 15, or 30 mg/kg. There was no statistical difference in the occurrence of cardiotoxic lesions when 15 or 30 mg/kg caffeine was combined with Ma Huang equivalent to 25 or 50 mg/kg ephedrine; likewise there was no statistical difference in the occurrence of cardiotoxic lesions when 7.25, 15, or 30 mg/kg caffeine was combined with 25 mg/kg ephedrine. These results show that the cardiotoxic effects of the herbal medicine, Ma Huang, are similar to that of ephedrine, the principal active ingredient in the herbal medicine. The combination of Ma Huang or ephedrine with caffeine enhanced the cardiotoxicity over that with the herbal medicine or the active ingredient alone. PMID:17676524

  5. Caffeine and cardiovascular health.

    PubMed

    Turnbull, Duncan; Rodricks, Joseph V; Mariano, Gregory F; Chowdhury, Farah

    2017-10-01

    This report evaluates the scientific literature on caffeine with respect to potential cardiovascular outcomes, specifically relative risks of total cardiovascular disease (CVD), coronary heart disease (CHD) and acute myocardial infarction (AMI), effects on arrhythmia, heart failure, sudden cardiac arrest, stroke, blood pressure, hypertension, and other biomarkers of effect, including heart rate, cerebral blood flow, cardiac output, plasma homocysteine levels, serum cholesterol levels, electrocardiogram (EKG) parameters, heart rate variability, endothelial/platelet function and plasma/urine catecholamine levels. Caffeine intake has been associated with a range of reversible and transient physiological effects broadly and cardiovascular effects specifically. This report attempts to understand where the delineations exist in caffeine intake and corresponding cardiovascular effects among various subpopulations. The available literature suggests that cardiovascular effects experienced by caffeine consumers at levels up to 600 mg/day are in most cases mild, transient, and reversible, with no lasting adverse effect. The point at which caffeine intake may cause harm to the cardiovascular system is not readily identifiable in part because data on the effects of daily intakes greater than 600 mg is limited. However, the evidence considered within this review suggests that typical moderate caffeine intake is not associated with increased risks of total cardiovascular disease; arrhythmia; heart failure; blood pressure changes among regular coffee drinkers; or hypertension in baseline populations. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  6. An enhanced treatment program with markedly reduced mortality after a transtibial or higher non-traumatic lower extremity amputation

    PubMed Central

    Kristensen, Morten T; Holm, Gitte; Krasheninnikoff, Michael; Jensen, Pia S; Gebuhr, Peter

    2016-01-01

    Background and purpose Historically, high 30-day and 1-year mortality post-amputation rates (> 30% and 50%, respectively) have been reported in patients with a transtibial or higher non-traumatic lower extremity amputation (LEA). We evaluated whether allocating experienced staff and implementing an enhanced, multidisciplinary recovery program would reduce the mortality rates. We also determined factors that influenced mortality rates. Patients and methods 129 patients with a LEA were consecutively included over a 2-year period, and followed after admission to an acute orthopedic ward. Mortality was compared with historical and concurrent national controls in Denmark. Results The 30-day and 1-year mortality rates were 16% and 37%, respectively, in the intervention group, as compared to 35% and 59% in the historical control group treated in the same orthopedic ward. Cox proportional harzards models adjusted for age, sex, residential and health status, the disease that caused the amputation, and the index amputation level showed that 30-day and 1-year mortality risk was reduced by 52% (HR =0.48, 95% CI: 0.25–0.91) and by 46% (HR =0.54, 95% CI: 0.35–0.86), respectively, in the intervention group. The risk of death was increased for patients living in a nursing home, for patients with a bilateral LEA, and for patients with low health status. Interpretation With similarly frail patient groups and instituting an enhanced program for patients after LEA, the risks of death by 30 days and by 1 year after LEA were markedly reduced after allocating staff with expertise. PMID:27088484

  7. Depressing effect of caffeine at crayfish neuromuscular synapses II. Initial search for possible sites of action.

    PubMed

    Celenza, Kathryn M; Shugert, Elizabeth; Vélez, Samuel J

    2007-05-01

    Caffeine's unexpected depression of synaptic transmission in the superficial flexor muscle system (SFM) of Procambarus clarkii was studied by looking at three known sites of action of this drug: via adenosine and ryanodine receptors and inhibition of phosphodiesterase.1. JPs did not change in size when exposed to physiological concentrations of adenosine, suggesting that the SFM system lacks presynaptic adenosine receptors.2. JPs slightly increased in size in the presence of a phosphodiesterase inhibitor, the opposite response to that obtained with caffeine, suggesting that caffeine is not acting via this pathway.3. A calcium ionophore immediately enhanced synaptic transmission in the SFM system but when given in combination with caffeine the enhancement is reduced and declines over time.4. Serotonin enhanced synaptic transmission in the SFM system, but when given in combination with caffeine this enhancement was not observed.5. These caffeine effects are interpreted in terms of alterations to the calcium homeostatic mechanisms of the terminals.

  8. Antibody-enhanced dengue disease generates a marked CNS inflammatory response in the black-tufted marmoset Callithrix penicillata.

    PubMed

    Vasconcelos, Barbara Cristina Baldez; Vieira, Juliana Almeida; Silva, Geane Oliveira; Fernandes, Taiany Nogueira; Rocha, Luciano Chaves; Viana, André Pereira; Serique, Cássio Diego Sá; Filho, Carlos Santos; Bringel, Raissa Aires Ribeiro; Teixeira, Francisco Fernando Dacier Lobato; Ferreira, Milene Silveira; Casseb, Samir Mansour Moraes; Carvalho, Valéria Lima; de Melo, Karla Fabiane Lopes; de Castro, Paulo Henrique Gomes; Araújo, Sanderson Corrêa; Diniz, José Antonio Picanço; Demachki, Samia; Anaissi, Ana Karyssa Mendes; Sosthenes, Marcia Consentino Kronka; Vasconcelos, Pedro Fernando da Costa; Anthony, Daniel Clive; Diniz, Cristovam Wanderley Picanço; Diniz, Daniel Guerreiro

    2016-02-01

    Severe dengue disease is often associated with long-term neurological impairments, but it is unclear what mechanisms are associated with neurological sequelae. Previously, we demonstrated antibody-enhanced dengue disease (ADE) dengue in an immunocompetent mouse model with a dengue virus 2 (DENV2) antibody injection followed by DENV3 virus infection. Here we migrated this ADE model to Callithrix penicillata. To mimic human multiple infections of endemic zones where abundant vectors and multiple serotypes co-exist, three animals received weekly subcutaneous injections of DENV3 (genotype III)-infected supernatant of C6/36 cell cultures, followed 24 h later by anti-DENV2 antibody for 12 weeks. There were six control animals, two of which received weekly anti-DENV2 antibodies, and four further animals received no injections. After multiple infections, brain, liver, and spleen samples were collected and tissue was immunolabeled for DENV3 antigens, ionized calcium binding adapter molecule 1, Ki-67, TNFα. There were marked morphological changes in the microglial population of ADE monkeys characterized by more highly ramified microglial processes, higher numbers of trees and larger surface areas. These changes were associated with intense TNFα-positive immunolabeling. It is unclear why ADE should generate such microglial activation given that IgG does not cross the blood-brain barrier, but this study reveals that in ADE dengue therapy targeting the CNS host response is likely to be important.

  9. Conditioned Reinforcement and Locomotor Activating Effects of Caffeine and Ethanol Combinations in Mice

    PubMed Central

    Hilbert, Megan L.T.; May, Christina E.; Griffin, William C.

    2013-01-01

    A growing trend among ethanol drinkers, especially young adults, is to combine caffeinated energy drinks with ethanol during a drinking episode. The primary active ingredient of these mixers is caffeine, which may significantly interact with ethanol. We tested the two hypotheses that caffeine would enhance ethanol-conditioned place preference and also enhance ethanol-stimulated locomotor activity. The interactive pharmacology of ethanol and caffeine was examined in C57BL/6J (B6) mice in a conditioned place preference procedure with 1.75 g/kg ethanol and 3 mg/kg caffeine. Additionally, we used B6 mice to evaluate ethanol/caffeine combinations on locomotor activity using 3 doses of ethanol (1.75, 2.5 and 3.25 g/kg) and 2 two doses of caffeine (3 and 15 mg/kg). Both ethanol and caffeine administered alone increased preference for the drug paired side, though the effect of caffeine was more modest than that of ethanol. The drug combination produced significant place preference itself, but this was not greater than that for ethanol alone. Additionally, the combination of caffeine and ethanol significantly increased locomotion compared to giving either drug alone. The effect was strongest with a stimulatory dose of ethanol (1.75 g/kg) and waned with increasing doses of ethanol. Thus, combinations of caffeine and ethanol had significant conditioned reinforcing and locomotor activating effects in mice. PMID:23872371

  10. The effect of caffeine on excitation-contraction coupling in skeletal and smooth muscle.

    PubMed

    Syson, A J; Huddart, H

    1976-06-01

    1. For cockroach skeletal muscle, 2 mM caffeine considerably lowered the mechanical threshold without affecting the membrane potential. Constractures were induced by 8-10 mM caffeine. 2. In rat ileal smooth muscle, 1-10 mM caffeine inhibited spontaneous contractile behaviour, abolished spike activity and reduced KCl-induced contracture tension. 3. Enhanced spike activity associated with the KCl-induced phasic contraction was abolished by caffeine, the degree of caffeine-induced relaxation being proportional to the concentration employed. These relaxations were not accompanied by membrane hyperpolarization. 4. The present results accord with previous work which has shown that caffeine increases myoplasmic free calcium in the skeletal muscle and lowers it in the smooth muscle. It is suggested that caffiene releases bound calcium in the former muscle and promotes binding in the latter. 5. It is further suggested that in the smooth muscle caffeine may reduce the membrane permeability to calcium.

  11. Evaluation of the Reproductive and Developmental Risks of Caffeine

    PubMed Central

    Brent, Robert L; Christian, Mildred S; Diener, Robert M

    2011-01-01

    A risk analysis of in utero caffeine exposure is presented utilizing epidemiological studies and animal studies dealing with congenital malformation, pregnancy loss, and weight reduction. These effects are of interest to teratologists, because animal studies are useful in their evaluation. Many of the epidemiology studies did not evaluate the impact of the “pregnancy signal,” which identifies healthy pregnancies and permits investigators to identify subjects with low pregnancy risks. The spontaneous abortion epidemiology studies were inconsistent and the majority did not consider the confounding introduced by not considering the pregnancy signal. The animal studies do not support the concept that caffeine is an abortafacient for the wide range of human caffeine exposures. Almost all the congenital malformation epidemiology studies were negative. Animal pharmacokinetic studies indicate that the teratogenic plasma level of caffeine has to reach or exceed 60 µg/ml, which is not attainable from ingesting large amounts of caffeine in foods and beverages. No epidemiological study described the “caffeine teratogenic syndrome.” Six of the 17 recent epidemiology studies dealing with the risk of caffeine and fetal weight reduction were negative. Seven of the positive studies had growth reductions that were clinically insignificant and none of the studies cited the animal literature. Analysis of caffeine's reproductive toxicity considers reproducibility and plausibility of clinical, epidemiological, and animal data. Moderate or even high amounts of beverages and foods containing caffeine do not increase the risks of congenital malformations, miscarriage or growth retardation. Pharmacokinetic studies markedly improve the ability to perform the risk analyses. Birth Defects Res (Part B) 92:152–187, 2011. © 2011 Wiley-Liss, Inc. PMID:21370398

  12. Caffeine, extraversion and working memory.

    PubMed

    Smith, Andrew P

    2013-01-01

    Research has shown that extraverts performing a working memory task benefit more from caffeine than do introverts. The present study aimed to replicate this and extend our knowledge by using a lower dose of caffeine (65 mg) and a range of tasks related to different components of working memory. In addition, tasks assessing psychomotor speed and the encoding of new information were included to determine whether caffeine-extraversion interactions were restricted to working memory tasks. A double-blind design was used, with 128 participants being randomly assigned to caffeinated or de-caffeinated coffee conditions. The results showed that caffeine interacted with extraversion in the predicted direction for serial recall and running memory tasks. Caffeine improved simple reaction time and the speed of encoding of new information, effects which were not modified by extraversion. These results suggest possible biological mechanisms underlying effects of caffeine on cognitive performance.

  13. The effect of caffeine ingestion on delayed onset muscle soreness.

    PubMed

    Hurley, Caitlin F; Hatfield, Disa L; Riebe, Deborah A

    2013-11-01

    The beneficial effects of caffeine on aerobic activity and resistance training performance are well documented. However, less is known concerning caffeine's potential role in reducing perception of pain and soreness during exercise. In addition, there is no information regarding the effects of caffeine on delayed onset muscle soreness (DOMS). The primary purpose of this study was to examine the effect of caffeine ingestion on muscle soreness, blood enzyme activity, and performance after a bout of elbow flexion/extension exercise. Nine low-caffeine-consuming males (body mass: 76.68 ± 8.13 kg; height: 179.18 ± 9.35 cm; age: 20 ± 1 year) were randomly assigned to ingest either caffeine or placebo 1 hour before completing 4 sets of 10 bicep curls on a preacher bench, followed by a fifth set in which subjects completed as many repetitions as possible. Soreness and soreness on palpation intensity were measured using three 0-10 visual analog scales before exercise, and 24, 48, 72, 96, and 120 hours after exercise. After a washout period, subjects crossed over to the other treatment group. Caffeine ingestion resulted in significantly (p ≤ 0.05) lower levels of soreness on day 2 and day 3 compared with placebo. Total repetitions in the final set of exercise increased with caffeine ingestion compared with placebo. This study demonstrates that caffeine ingestion immediately before an upper-body resistance training out enhances performance. A further beneficial effect of sustained caffeine ingestion in the days after the exercise bout is an attenuation of DOMS. This decreased perception of soreness in the days after a strenuous resistance training workout may allow individuals to increase the number of training sessions in a given time period.

  14. Caffeine content of decaffeinated coffee.

    PubMed

    McCusker, Rachel R; Fuehrlein, Brian; Goldberger, Bruce A; Gold, Mark S; Cone, Edward J

    2006-10-01

    Caffeine is the most widely consumed drug in the world with coffee representing a major source of intake. Despite widespread availability, various medical conditions necessitate caffeine-restricted diets. Patients on certain prescription medications are advised to discontinue caffeine intake. Such admonition has implications for certain psychiatric patients because of pharmacokinetic interactions between caffeine and certain anti-anxiety drugs. In an effort to abstain from caffeine, patients may substitute decaffeinated for caffeinated coffee. However, decaffeinated beverages are known to contain caffeine in varying amounts. The present study determined the caffeine content in a variety of decaffeinated coffee drinks. In phase 1 of the study, 10 decaffeinated samples were collected from different coffee establishments. In phase 2 of the study, Starbucks espresso decaffeinated (N=6) and Starbucks brewed decaffeinated coffee (N=6) samples were collected from the same outlet to evaluate variability of caffeine content of the same drink. The 10 decaffeinated coffee samples from different outlets contained caffeine in the range of 0-13.9 mg/16-oz serving. The caffeine content for the Starbucks espresso and the Starbucks brewed samples collected from the same outlet were 3.0-15.8 mg/shot and 12.0-13.4 mg/16-oz serving, respectively. Patients vulnerable to caffeine effects should be advised that caffeine may be present in coffees purported to be decaffeinated. Further research is warranted on the potential deleterious effects of consumption of "decaffeinated" coffee that contains caffeine on caffeine-restricted patients. Additionally, further exploration is merited for the possible physical dependence potential of low doses of caffeine such as those concentrations found in decaffeinated coffee.

  15. Energy drink ingredients. Contribution of caffeine and taurine to performance outcomes.

    PubMed

    Peacock, Amy; Martin, Frances Heritage; Carr, Andrea

    2013-05-01

    While the performance-enhancing effects of energy drinks are commonly attributed to caffeine, recent research has shown greater facilitation of performance post-consumption than typically expected from caffeine content alone. Consequently, the aim of the present study was to investigate the independent and combined effect of taurine and caffeine on behavioural performance, specifically reaction time. Using a double-blind, placebo-controlled, crossover, within-subjects design, female undergraduates (N=19) completed a visual oddball task and a stimulus degradation task 45min post-ingestion of capsules containing: (i) 80mg caffeine, (ii) 1000mg taurine, (iii) caffeine and taurine combined, and (iv) matched placebo. Participants completed each treatment condition, with sessions separated by a minimum 2-day washout period. Whereas no significant treatment effects were recorded for reaction time in the visual oddball task, facilitative caffeine effects were evident in the stimulus degradation task, with significantly faster reaction time in active relative to placebo caffeine conditions. Furthermore, there was a trend towards faster mean reaction time in the caffeine condition relative to the taurine condition and combined caffeine and taurine condition. Thus, treatment effects were task-dependent, in that independent caffeine administration exerted a positive effect on performance, and co-administration with taurine tended to attenuate the facilitative effects of caffeine in the stimulus degradation task only.

  16. Ad lib caffeine consumption, symptoms of caffeinism, and academic performance.

    PubMed

    Gilliland, K; Andress, D

    1981-04-01

    The authors explored the relationship between ad lib caffeine consumption in college students and the incidence of caffeinism, characterized by heightened anxiety, depression, and various psychophysiological reactions. Students were randomly selected from four groups (abstainers from caffeine and low, moderate, and high consumers). A survey battery assessed the effects of caffeine, incidence of psychophysiological disorders, state-trait anxiety, and depression. The moderate and high consumer groups combined reported significantly higher trait anxiety and depression scores when compared with abstainers. The high consumer group also reported significantly higher levels of symptoms of caffeinism, higher frequency of psychophysiological disorders, and lower academic performance.

  17. Effects of Chronic Caffeine on Adenosine, Dopamine and Acetylcholine Systems in Mice

    PubMed Central

    Shi, D.; Nikodijević, O.; Jacobson, K. A.

    2012-01-01

    Chronic ingestion of caffeine by male NIH Swiss strain mice leads in about 3 days to a significant increase in A1-adenosine, nicotinic and muscarinic receptors, and a significant decrease of β1-adrenoceptors in cerebral cortical membranes. Plasma levels of caffeine in the chronically treated mice range from 0.70 to 5.7 μg/ml. The changes in receptors reverse after withdrawal of caffeine within 7 days. An increase in nitrendipine binding sites, associated with L-type calcium channels, also occurs within 4 days and has reversed in 7 days after withdrawal. There is no change in the levels of striatal nicotinic receptors or D2-dopamine receptors, nor of [3H]cocaine binding to dopamine uptake sites. Levels of opioid receptors are either increased (δ) or unaltered (μ, κ). σ-Receptors are unaltered. Stimulations of striatal adenylate cyclase by forskolin, dopamine and NECA are not significantly affected after chronic caffeine ingestion. The adenosine agonist, NECA, reverses the amphetamine-elicited increases in locomotor activity and partly reverses the cocaine-elicited increases. The NECA dose-response curve is multiphasic (depression, stimulation and then depression) versus amphetamine in control mice, but only depressant versus amphetamine in chronic caffeine mice, while being multiphasic versus cocaine in both control and chronic caffeine mice. NECA reverses the stimulation of locomotor activity elicited by the muscarinic antagonist, scopolamine, and is more effective in the chronic caffeine mice. The behavioral depressant effects of the muscarinic agonist, oxotremorine, are not markedly altered after chronic caffeine ingestion. The behavioral depressant effects of nicotine are abolished after chronic caffeine ingestion, while the behavioral depressant effects of the nicotinic antagonist, mecamylamine, are not markedly altered after chronic caffeine ingestion. In combination with caffeine, nicotine has depressant effects in control mice, while having biphasic

  18. The acute effects of caffeinated versus non-caffeinated alcoholic beverage on driving performance and attention/reaction time.

    PubMed

    Howland, Jonathan; Rohsenow, Damaris J; Arnedt, J Todd; Bliss, Caleb A; Hunt, Sarah K; Calise, Tamara Vehige; Heeren, Timothy; Winter, Michael; Littlefield, Caroline; Gottlieb, Daniel J

    2011-02-01

    Marketing that promotes mixing caffeinated 'energy' drinks with alcoholic beverages (e.g. Red Bull with vodka) targets young drinkers and conveys the expectation that caffeine will offset the sedating effects of alcohol and enhance alertness. Such beliefs could result in unwarranted risk taking (e.g. driving while intoxicated). The aim of this study was to assess the acute effects of caffeinated versus non-caffeinated alcoholic beverages on a simulated driving task and attention/reaction time. We conducted a 2 × 2 between-groups randomized trial in which participants were randomized to one of four conditions: beer and non-alcoholic beer, with and without caffeine added. Caffeine was added in the same proportion as found in a commercially available caffeinated beer (69 mg/12 oz of beer at 4.8% alc. by vol). Participants were 127 non-dependent, heavy episodic, young adult drinkers (age 21-30) who were college students or recent graduates. The target breath alcohol level was 0.12 g%. Driving performance was assessed with a driving simulator; sustained attention/reaction with the Psychomotor Vigilance Task (PVT). Across the driving and attention/reaction time we found main effects for alcohol, with alcohol significantly impairing driving and sustained attention/reaction time, with mainly large statistical effects; however, the addition of caffeine had no main or interaction effects on performance. The addition of caffeine to alcohol does not appear to enhance driving or sustained attention/reaction time performance relative to alcohol alone. © 2010 The Authors, Addiction © 2010 Society for the Study of Addiction.

  19. Chronic caffeine exposure potentiates nicotine self-administration in rats.

    PubMed

    Shoaib, M; Swanner, L S; Yasar, S; Goldberg, S R

    1999-03-01

    The prevalence of tobacco smoking and coffee drinking place nicotine and caffeine among the most used licit drugs in many societies and their consumption is often characterised by concurrent use. The pharmacological basis for any putative interaction between these drugs remains unclear. Epidemiological reports support anecdotal evidence, which suggests that smokers consume caffeine to enhance the euphoric effects of nicotine. The aim of the present experiment was to examine effects of chronic exposure to caffeine on responding maintained by nicotine. Sprague-Dawley rats consuming caffeine (approximately 150-180 mg/kg per day) in their drinking water for 7 days prior to the beginning and throughout behavioural testing acquired intravenous nicotine self-administration (0.03 mg/kg per infusion) more rapidly than did controls. In a cross-over design, exclusion of caffeine brought levels of nicotine self-administration back to baseline, while adding caffeine to the drinking water of control rats increased responding maintained by nicotine over 90%. These findings strongly suggest that caffeine can potentiate the reinforcing properties of nicotine, thus highlighting the importance of environmental factors in shaping and maintaining tobacco smoking.

  20. The paradox of caffeine-zolpidem interaction: a network analysis.

    PubMed

    Myslobodsky, Michael

    2009-10-01

    A widely prescribed and potent short-acting hypnotic, zolpidem has become the mainstay for the treatment of middle-of-the-night sleeplessness. It is expected to be antagonized by caffeine. Paradoxically, in some cases caffeine appears to slightly enhance zolpidem sedation. The pharmacokinetic and pharmacodynamic nature of this odd effect remains unexplored. The purpose of this study is to reproduce a hypothetical molecular network recruited by caffeine when co-administered with zolpidem using Ingenuity Pathway Analysis. Thus generated, network drew attention to several possible contributors to caffeine sedation, such as tachykinin precursor 1, cannabinoid, and GABA receptors. The present overview is centered on the possibility that caffeine potentiation of zolpidem sedation does not involve a centralized interaction of specific neurotransmitters, but rather is contributed by its antioxidant capacity. It is proposed that by modifying the cellular redox state, caffeine ultimately reduces the pool of reactive oxygen species, thereby increasing the bioavailability of endogenous melatonin for interaction with zolpidem. This side effect of caffeine encourages further studies of multiple antioxidants as an attractive way to potentially increasing somnolence.

  1. Ergogenic effects of low doses of caffeine on cycling performance.

    PubMed

    Jenkins, Nathan T; Trilk, Jennifer L; Singhal, Arpit; O'Connor, Patrick J; Cureton, Kirk J

    2008-06-01

    The purpose of this experiment was to learn whether low doses of caffeine have ergogenic, perceptual, and metabolic effects during cycling. To determine the effects of 1, 2, and 3 mg/kg caffeine on cycling performance, differentiated ratings of perceived exertion (D-RPE), quadriceps pain intensity, and metabolic responses to cycling exercise, 13 cyclists exercised on a stationary ergometer for 15 min at 80% VO, then, after 4 min of active recovery, completed a 15-min VO2peak performance ride 60 min after ingesting caffeine or placebo. Work done (kJ/kg) during the performance ride was used as a measure of performance. D-RPE, pain ratings, and expired-gas data were obtained every 3 min, and blood lactate concentrations were obtained at 15 and 30 min. Compared with placebo, caffeine doses of 2 and 3 mg/kg increased performance by 4% (95% CI: 1.0-6.8%, p = .02) and 3% (95% CI: -0.4% to 6.8%, p = .077), respectively. These effects were ergogenic, on average, but varied considerably in magnitude among individual cyclists. There were no effects of caffeine on D-RPE or pain throughout the cycling task. Selected metabolic variables were affected by caffeine, consistent with its known actions. The authors conclude that caffeine preparations of 2 and 3 mg/kg enhanced performance, but future work should aim to explain the considerable interindividual variability of the drug's ergogenic properties.

  2. Stretch Marks

    MedlinePlus

    ... like during puberty), that person may get fine lines on the body called stretch marks. Stretch marks happen when the skin is pulled by rapid growth or stretching. Although the skin is usually fairly elastic, when it's overstretched, the normal production of collagen (the major protein that makes up ...

  3. Effects of Caffeine and Lycopene in Experimentally Induced Diabetes Mellitus.

    PubMed

    Ozmen, Ozlem; Topsakal, Senay; Haligur, Mehmet; Aydogan, Ahmet; Dincoglu, Dilnur

    2016-04-01

    Diabetes mellitus (DM) is a global epidemic with increasing prevalence. The disease is chronic in nature, and patients must use antidiabetic drugs or insulin during their lifespan. Because of the difficulty of using injectable insulin preparations, patients and practitioners prefer to use oral antidiabetic drugs for prophylaxis and treatment. There are, however, numerous adverse effects of antidiabetic drugs and rapidly increasing attention is being paid to new nutraceutical drugs with fewer adverse effects. The purpose of this study was to evaluate the effects of caffeine and lycopene on streptozotocin (STZ)-induced DM in rats. Caffeine and lycopene were administered to the study groups by oral gavages for 1 month whereafter experimental diabetes was induced in 90 rats in 6 groups. There were no pathological effects of lycopene and caffeine on the pancreas. Marked vacuolization and degeneration were observed in STZ-treated groups. Caffeine and lycopene decreased the pathological findings and lowered the blood and urine glucose levels in the rats with STZ-induced DM, whereas these compounds increased serum insulin levels. This study showed that caffeine and lycopene provided protective effects against experimentally induced DM. The protective effects of lycopene were observed to be much greater than those of caffeine.

  4. Direct effects of caffeine on osteoblastic cells metabolism: the possible causal effect of caffeine on the formation of osteoporosis

    PubMed Central

    Tsuang, Yang-Hwei; Sun, Jui-Sheng; Chen, Li-Ting; Sun, Samuel Chung-Kai; Chen, San-Chi

    2006-01-01

    Background Caffeine consumption has been reported to decrease bone mineral density (BMD), increase the risk of hip fracture, and negatively influence calcium retention. In this study, we investigated the influence of caffeine on the osteoblasts behaviour. Method Osteoblasts derived from newborn Wistar-rat calvaria was used in this study. The effects of various concentrations of caffeine on bone cell activities were evaluated by using MTT assay. Alkaline phosphatase (ALP) staining, von Kossa staining and biochemical parameters including ALP, lactate dehydrogenase (LDH), prostaglandin E2 (PGE2) and total protein were performed at day 1, 3, and 7. DNA degradation analysis under the caffeine influence was also performed. Results and discussion The results showed that the viability of the osteoblasts, the formation of ALP positive staining colonies and mineralization nodules formation in the osteoblasts cultures decreased significantly in the presence of 10 mM caffeine. The intracellular LDH, ALP and PGE2 content decreased significantly, the LDH and PGE2 secreted into the medium increased significantly. The activation of an irreversible commitment to cell death by caffeine was clearly demonstrated by DNA ladder staining. Conclusion In summary, our results suggest that caffeine has potential deleterious effect on the osteoblasts viability, which may enhance the rate of osteoblasts apoptosis. PMID:17150127

  5. Caffeine Reinforces Flavor Preference and Behavior in Moderate Users but Not in Low Caffeine Users

    ERIC Educational Resources Information Center

    Dack, Charlotte; Reed, Phil

    2009-01-01

    The study examined the role of caffeine consumption in caffeine reinforcement. Previous findings have shown that caffeine reinforced flavor preference in moderate caffeine consumers who are caffeine deprived. However, most of these studies have employed rating procedures only, and have not shown the effectiveness of caffeine to reinforce behaviors…

  6. Caffeine Reinforces Flavor Preference and Behavior in Moderate Users but Not in Low Caffeine Users

    ERIC Educational Resources Information Center

    Dack, Charlotte; Reed, Phil

    2009-01-01

    The study examined the role of caffeine consumption in caffeine reinforcement. Previous findings have shown that caffeine reinforced flavor preference in moderate caffeine consumers who are caffeine deprived. However, most of these studies have employed rating procedures only, and have not shown the effectiveness of caffeine to reinforce behaviors…

  7. Effects of caffeine on the inflammatory response induced by a 15-km run competition.

    PubMed

    Tauler, Pedro; Martínez, Sonia; Moreno, Carlos; Monjo, Marta; Martínez, Pau; Aguiló, Antoni

    2013-07-01

    The objective of this study is as follows: 1) to determine the effects of caffeine supplementation on the inflammatory response (IL-6 and IL-10 levels and leukocyte numbers) induced by a 15-km run competition and 2) to examine the effect of caffeine supplementation on the energetic metabolites as well as on the exercise-induced oxidative stress. A double-blinded study of supplementation with caffeine was performed. Athletes participating in the study (n = 33) completed a 15-km run competition. Before competition, athletes took 6 mg · kg(-1) body weight of caffeine (caffeine group, n = 17) or a placebo (placebo group, n = 16). Blood samples were taken before and after competition (immediately and after 2-h recovery). Leukocyte numbers were determined in blood. Concentrations of oxidative stress markers, antioxidants, interleukins (IL-6 and IL-10), caffeine, adrenaline, and energetic metabolites were measured in plasma or serum. Caffeine supplementation induced higher increases in circulating total leukocytes and neutrophils, with significant differences between groups after recovery. Adrenaline, glucose, and lactate levels increased after exercise, with higher increases in the caffeine group. Exercise induced significant increases in IL-6 and IL-10 plasma levels, with higher increases in the caffeine group. Caffeine supplementation induced higher increases in oxidative stress markers after the competition. Caffeine supplementation induced higher levels of IL-6 and IL-10 in response to exercise, enhancing the anti-inflammatory response. The caffeine-induced increase in adrenaline could be responsible for the higher increase in IL-6 levels, as well as for the increased lactate levels. Furthermore, caffeine seems to enhance oxidative stress induced by exercise.

  8. Caffeinated forage tricks honeybees into increasing foraging and recruitment behaviors.

    PubMed

    Couvillon, Margaret J; Al Toufailia, Hasan; Butterfield, Thomas M; Schrell, Felix; Ratnieks, Francis L W; Schürch, Roger

    2015-11-02

    In pollination, plants provide food reward to pollinators who in turn enhance plant reproduction by transferring pollen, making the relationship largely cooperative; however, because the interests of plants and pollinators do not always align, there exists the potential for conflict, where it may benefit both to cheat the other [1, 2]. Plants may even resort to chemistry: caffeine, a naturally occurring, bitter-tasting, pharmacologically active secondary compound whose main purpose is to detract herbivores, is also found in lower concentrations in the nectar of some plants, even though nectar, unlike leaves, is made to be consumed by pollinators. [corrected]. A recent laboratory study showed that caffeine may lead to efficient and effective foraging by aiding honeybee memory of a learned olfactory association [4], suggesting that caffeine may enhance bee reward perception. However, without field data, the wider ecological significance of caffeinated nectar remains difficult to interpret. Here we demonstrate in the field that caffeine generates significant individual- and colony-level effects in free-flying worker honeybees. Compared to a control, a sucrose solution with field-realistic doses of caffeine caused honeybees to significantly increase their foraging frequency, waggle dancing probability and frequency, and persistency and specificity to the forage location, resulting in a quadrupling of colony-level recruitment. An agent-based model also demonstrates how caffeine-enhanced foraging may reduce honey storage. Overall, caffeine causes bees to overestimate forage quality, tempting the colony into sub-optimal foraging strategies, which makes the relationship between pollinator and plant less mutualistic and more exploitative. VIDEO ABSTRACT. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Caffeine and sports performance.

    PubMed

    Burke, Louise M

    2008-12-01

    Athletes are among the groups of people who are interested in the effects of caffeine on endurance and exercise capacity. Although many studies have investigated the effect of caffeine ingestion on exercise, not all are suited to draw conclusions regarding caffeine and sports performance. Characteristics of studies that can better explore the issues of athletes include the use of well-trained subjects, conditions that reflect actual practices in sport, and exercise protocols that simulate real-life events. There is a scarcity of field-based studies and investigations involving elite performers. Researchers are encouraged to use statistical analyses that consider the magnitude of changes, and to establish whether these are meaningful to the outcome of sport. The available literature that follows such guidelines suggests that performance benefits can be seen with moderate amounts (~3 mg.kg-1 body mass) of caffeine. Furthermore, these benefits are likely to occur across a range of sports, including endurance events, stop-and-go events (e.g., team and racquet sports), and sports involving sustained high-intensity activity lasting from 1-60 min (e.g., swimming, rowing, and middle and distance running races). The direct effects on single events involving strength and power, such as lifts, throws, and sprints, are unclear. Further studies are needed to better elucidate the range of protocols (timing and amount of doses) that produce benefits and the range of sports to which these may apply. Individual responses, the politics of sport, and the effects of caffeine on other goals, such as sleep, hydration, and refuelling, also need to be considered.

  10. Adolescent caffeine consumption and self-reported violence and conduct disorder.

    PubMed

    Kristjansson, Alfgeir L; Sigfusdottir, Inga Dora; Frost, Stephanie S; James, Jack E

    2013-07-01

    Caffeine is the most widely used psychoactive substance in the world and currently the only one legally available to children and adolescents. The sale and use of caffeinated beverages has increased markedly among adolescents during the last decade. However, research on caffeine use and behaviors among adolescents is scarce. We investigate the relationship between adolescent caffeine use and self-reported violent behaviors and conduct disorders in a population-based cross-sectional sample of 3,747 10th grade students (15-16 years of age, 50.2 % girls) who were enrolled in the Icelandic national education system during February 2012. Through a series of multiple regression models, while controlling for background factors, Attention Deficit Hyperactivity Disorder symptoms and current medication and peer delinquency, and including measures on substance use, our findings show robust additive explanatory power of caffeine for both violent behaviors and conduct disorders. In addition, the association of caffeine to the outcomes is significantly stronger for girls than boys for both violent behaviors and conduct disorders. Future studies are needed to examine to what extent, if at all, these relationships are causal. Indication of causal connections between caffeine consumption and negative outcomes such as those reported here would call into question the acceptability of current policies concerning the availability of caffeine to adolescents and the targeting of adolescence in the marketing of caffeine products.

  11. Caffeine consumption among medical students.

    PubMed

    Mino, Y; Yasuda, N; Fujimura, T; Ohara, H

    1990-12-01

    Recently, caffeine consumption in Japan is thought to have increased. Although caffeine had been considered to be harmless, there have been studies which suggests an association between caffeine and health and give rise to vigorous discussion. However, in Japan, there have been few epidemiological studies on caffeine consumption among a general population. A questionnaire survey was conducted among medical students and the results were as follows: 1) High dose users (estimated daily caffeine use is 250 mg or more) were observed in 15.2% and the proportion was higher in males than in females. 2) The respondents gave sleepiness, dry mouth and so on, as reasons for taking caffeine beverages, and gave, as the effects of caffeine, becoming clear-headed, shaking off sleepiness, and epigastric discomfort or pain. 3) A third of respondents have experienced taking caffeine tablets and ampules to shake off sleepiness and, in males, the more caffeine they had daily, the more who reported the experience. 4) Caffeine consumption has an association with alcohol use and smoking habit among males.

  12. Marking Time

    ERIC Educational Resources Information Center

    Foster, Colin

    2011-01-01

    Teachers say that they would gladly teach a day in the classroom if at the end of the day they could leave and have no marking. There is a common staffroom perception that mathematics teachers have it easy when it comes to marking. In arts subjects, setting an essay can be a fairly straightforward matter--a one-line question may suffice--but…

  13. Marking Time

    ERIC Educational Resources Information Center

    Foster, Colin

    2011-01-01

    Teachers say that they would gladly teach a day in the classroom if at the end of the day they could leave and have no marking. There is a common staffroom perception that mathematics teachers have it easy when it comes to marking. In arts subjects, setting an essay can be a fairly straightforward matter--a one-line question may suffice--but…

  14. Caffeine expectancies but not caffeine reduce depletion-induced aggression.

    PubMed

    Denson, Thomas F; Jacobson, Mandi; von Hippel, William; Kemp, Richard I; Mak, Tinnie

    2012-03-01

    Caffeine is the most widely consumed central nervous system stimulant in the world, yet little is known about its effects on aggressive behavior. Individuals often consume caffeine to increase energy and ward off mental depletion. Because mental depletion increases aggression when people are provoked, caffeine might reduce aggression by ameliorating the negative effects of depletion. In 2 experiments, participants consumed a 200-mg caffeine tablet or a placebo, were mentally depleted or not, and then provoked and given the opportunity to retaliate with a blast of white noise. Results showed that consuming a placebo reduced aggression relative to both caffeine (Experiments 1 and 2) and a no-pill control condition (Experiment 2). These data suggest that expectancies about the effects of caffeine in the absence of the pharmacological effects of the drug can reduce aggression when mentally depleted.

  15. Pre-existent expectancy effects in the relationship between caffeine and performance.

    PubMed

    Elliman, Nicola A; Ash, Jennifer; Green, Michael W

    2010-10-01

    The present study investigated the impact of pre-existent expectancy regarding the effects of the caffeine load of a drink and the perception of the caffeine content on subjective mood and vigilance performance. Caffeine deprived participants (N=25) were tested in four conditions (within subjects design), using a 2×2 design, with caffeine load and information regarding the caffeine content of the drink. In two sessions, they were given caffeinated coffee and in two were given decaffeinated coffee. Within these two conditions, on one occasion they were given accurate information about the drink and on the other they were given inaccurate information about the drink. Mood and vigilance performance were assessed post ingestion. Caffeine was found to enhance performance, but only when participants were accurately told they were receiving it. When decaffeinated coffee was given, performance was poorer, irrespective of expectancy. However, when caffeine was given, but participants were told it was decaffeinated coffee, performance was as poor as when no caffeine had been administered. There were no easily interpretable effects on mood. The pharmacological effects of caffeine appear to act synergistically with expectancy.

  16. Cardiac mechanical and electrophysiologic modulations of guinea-pig by caffeine and thapsigargin.

    PubMed

    Nario, K; Satoh, H

    1996-10-01

    1. The effects of caffeine and thapsigargin on the contractile force and the action potential in guinea-pig papillary muscles were examined. 2. Caffeine (1 to 10 mM) initially increased contractile force in a concentration-dependent manner. Subsequently, 1 mM caffeine decreased it as compared with precaffeine level (but not significantly). At 5 mM or 10 mM, caffeine also decreased contractile force, but the decrease was still positive as compared with control level. 3. Exchange to low [Ca]o (0.9 mM) or high [K]o (8 mM) decreased steady-state value during exposure to 1 mM caffeine. Addition of 1 microM thapsigargin (TG) decreased the steady-state value during exposure to 1 mM caffeine, but enhanced it with 5 mM and 10 mM caffeine. TG (1 microM) alone increased the force. 4. In electrophysiologic, studies, caffeine shortened the action potential duration (APD) in a concentration-dependent manner. In the presence of caffeine (1 mM), high [K]o shortened APD and decreased the action potential amplitude and resting potential. 5. These results suggest that in the presence of caffeine and/or thapsigargin calcium overload might not occur in the left ventricular papillary muscles of the guinea-pig heart.

  17. Genome-Wide Screen of Genes Required for Caffeine Tolerance in Fission Yeast

    PubMed Central

    García-Santamarina, Sarela; Hoe, Kwang-Lae; Kim, Dong Uk; Sansó, Miriam; Zuin, Alice; Pérez, Pilar; Ayté, José; Hidalgo, Elena

    2009-01-01

    Background An excess of caffeine is cytotoxic to all eukaryotic cell types. We aim to study how cells become tolerant to a toxic dose of this drug, and the relationship between caffeine and oxidative stress pathways. Methodology/Principal Findings We searched for Schizosaccharomyces pombe mutants with inhibited growth on caffeine-containing plates. We screened a collection of 2,700 haploid mutant cells, of which 98 were sensitive to caffeine. The genes mutated in these sensitive clones were involved in a number of cellular roles including the H2O2-induced Pap1 and Sty1 stress pathways, the integrity and calcineurin pathways, cell morphology and chromatin remodeling. We have investigated the role of the oxidative stress pathways in sensing and promoting survival to caffeine. The Pap1 and the Sty1 pathways are both required for normal tolerance to caffeine, but only the Sty1 pathway is activated by the drug. Cells lacking Pap1 are sensitive to caffeine due to the decreased expression of the efflux pump Hba2. Indeed, ?hba2 cells are sensitive to caffeine, and constitutive activation of the Pap1 pathway enhances resistance to caffeine in an Hba2-dependent manner. Conclusions/Significance With our caffeine-sensitive, genome-wide screen of an S. pombe deletion collection, we have demonstrated the importance of some oxidative stress pathway components on wild-type tolerance to the drug. PMID:19672306

  18. Separate and joint effects of alcohol and caffeine on conflict monitoring and adaptation.

    PubMed

    Bailey, Kira; Amlung, Michael T; Morris, David H; Price, Mason H; Von Gunten, Curtis; McCarthy, Denis M; Bartholow, Bruce D

    2016-04-01

    Caffeine is commonly believed to offset the acute effects of alcohol, but some evidence suggests that cognitive processes remain impaired when caffeine and alcohol are coadministered. No previous study has investigated the separate and joint effects of alcohol and caffeine on conflict monitoring and adaptation, processes thought to be critical for self-regulation. This was the purpose of the current study. Healthy, young adult social drinkers recruited from the community completed a flanker task after consuming one of four beverages in a 2 × 2 experimental design: Alcohol + caffeine, alcohol + placebo caffeine, placebo alcohol + caffeine, or placebo alcohol + placebo caffeine. Accuracy, response time, and the amplitude of the N2 component of the event-related potential (ERP), a neural index of conflict monitoring, were examined as a function of whether or not conflict was present (i.e., whether or not flankers were compatible with the target) on both the previous trial and the current trial. Alcohol did not abolish conflict monitoring or adaptation. Caffeine eliminated conflict adaptation in sequential trials but also enhanced neural conflict monitoring. The combined effect of alcohol and caffeine was apparent only in how previous conflict affected the neural conflict monitoring response. Together, the findings suggest that caffeine leads to exaggeration of attentional resource utilization, which could provide short-term benefits but lead to problems conserving resources for when they are most needed.

  19. Effect of taurine and caffeine on sleep-wake activity in Drosophila melanogaster.

    PubMed

    Lin, Fang Ju; Pierce, Michael M; Sehgal, Amita; Wu, Tianyi; Skipper, Daniel C; Chabba, Radhika

    2010-01-01

    Caffeine and taurine are two major neuromodulators present in large quantities in many popular energy drinks. We investigated their effects on sleep-wake control in constant darkness using the fruit fly Drosophila as a model system. It has been shown that caffeine, as the most widely used psychostimulant, can boost arousal through the dopamine pathway in the mushroom bodies of flies. Taurine is a GABA receptor agonist, which is inhibitory to neuronal firing. We show here that flies receiving a low dose of caffeine (0.01%) increase locomotor activity by 25%, and decrease total sleep by 15%. Treatment with taurine at 0.1% to 1.5% reduces locomotor activity by 28% to 86%, and shifts it from diurnal to nocturnal. At 0.75%, taurine also increases total sleep by 50%. Our results show that taurine increases sleep, while caffeine, as previously reported, attenuates sleep. Flies treated with both caffeine and taurine exhibit two differential effects which depend upon the ratio of taurine to caffeine. A high taurine:caffeine ratio promotes sleep, while a low ratio of taurine:caffeine inhibits sleep to a greater extent than the equivalent amount of caffeine alone. This intriguing enhancement of caffeine action by low doses of taurine may account for the presence of both compounds in energy-promoting drinks such as Red Bull® and Monster®.

  20. Effect of taurine and caffeine on sleep–wake activity in Drosophila melanogaster

    PubMed Central

    Lin, Fang Ju; Pierce, Michael M; Sehgal, Amita; Wu, Tianyi; Skipper, Daniel C; Chabba, Radhika

    2010-01-01

    Caffeine and taurine are two major neuromodulators present in large quantities in many popular energy drinks. We investigated their effects on sleep-wake control in constant darkness using the fruit fly Drosophila as a model system. It has been shown that caffeine, as the most widely used psychostimulant, can boost arousal through the dopamine pathway in the mushroom bodies of flies. Taurine is a GABA receptor agonist, which is inhibitory to neuronal firing. We show here that flies receiving a low dose of caffeine (0.01%) increase locomotor activity by 25%, and decrease total sleep by 15%. Treatment with taurine at 0.1% to 1.5% reduces locomotor activity by 28% to 86%, and shifts it from diurnal to nocturnal. At 0.75%, taurine also increases total sleep by 50%. Our results show that taurine increases sleep, while caffeine, as previously reported, attenuates sleep. Flies treated with both caffeine and taurine exhibit two differential effects which depend upon the ratio of taurine to caffeine. A high taurine:caffeine ratio promotes sleep, while a low ratio of taurine:caffeine inhibits sleep to a greater extent than the equivalent amount of caffeine alone. This intriguing enhancement of caffeine action by low doses of taurine may account for the presence of both compounds in energy-promoting drinks such as Red Bull® and Monster®. PMID:23616711

  1. Effects of dietary caffeine on EEG, performance and mood when rested and sleep restricted.

    PubMed

    Keane, Michael A; James, Jack E

    2008-12-01

    Until recently, little account had been taken of the confounding effects of caffeine withdrawal and withdrawal reversal when examining the net effects of dietary caffeine. By including a manipulation involving sleep restriction, the present study aimed to extend recent findings from research in which caffeine withdrawal and withdrawal reversal were controlled. The main aims of the study were to examine the net effects of caffeine, as well as its potential restorative effects following sleep restriction, on EEG, performance and mood. A randomised cross-over design was used in which 15 participants alternated weekly between ingesting placebo and caffeine (1.75 mg/kg) three times daily for four consecutive weeks following either usual sleep or sleep restriction. EEG activity was measured at 32 sites during eyes closed, eyes open and performance of a vigilance task. Modest effects of caffeine were found in the delta and beta bandwidths, but no main effects of caffeine were observed in the theta or alpha bandwidths. Overall, the effects of caffeine on EEG activity were relatively few, weak and inconsistent, and no evidence was found of net restorative effects of caffeine for any outcome variables. The findings do not support the use of caffeine as a means for enhancing human function or as an antidote to the negative effects of sleep loss.

  2. A biomathematical model of the restoring effects of caffeine on cognitive performance during sleep deprivation.

    PubMed

    Ramakrishnan, Sridhar; Rajaraman, Srinivasan; Laxminarayan, Srinivas; Wesensten, Nancy J; Kamimori, Gary H; Balkin, Thomas J; Reifman, Jaques

    2013-02-21

    While caffeine is widely used as a countermeasure to sleep loss, mathematical models are lacking. Develop a biomathematical model for the performance-restoring effects of caffeine in sleep-deprived subjects. We hypothesized that caffeine has a multiplicative effect on performance during sleep loss. Accordingly, we first used a phenomenological two-process model of sleep regulation to estimate performance in the absence of caffeine, and then multiplied a caffeine-effect factor, which relates the pharmacokinetic-pharmacodynamic effects through the Hill equation, to estimate the performance-restoring effects of caffeine. We validated the model on psychomotor vigilance test data from two studies involving 12 subjects each: (1) single caffeine dose of 600mg after 64.5h of wakefulness and (2) repeated doses of 200mg after 20, 22, and 24h of wakefulness. Individualized caffeine models produced overall errors that were 19% and 42% lower than their population-average counterparts for the two studies. Had we not accounted for the effects of caffeine, the individualized model errors would have been 117% and 201% larger, respectively. The presented model captured the performance-enhancing effects of caffeine for most subjects in the single- and repeated-dose studies, suggesting that the proposed multiplicative factor is a feasible solution. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Separate and Joint Effects of Alcohol and Caffeine on Conflict Monitoring and Adaptation

    PubMed Central

    Bailey, Kira; Amlung, Michael T.; Morris, David H.; Price, Mason H.; Von Gunten, Curtis; McCarthy, Denis M.; Bartholow, Bruce D.

    2016-01-01

    Rationale Caffeine is commonly believed to offset the acute effects of alcohol, but some evidence suggests that cognitive processes remain impaired when caffeine and alcohol are co-administered. Objectives No previous study has investigated the separate and joint effects of alcohol and caffeine on conflict monitoring and adaptation, processes thought to be critical for self-regulation. This was the purpose of the current study. Methods Healthy, young adult social drinkers recruited from the community completed a flanker task after consuming one of four beverages in a 2 × 2 experimental design: Alcohol + Caffeine; Alcohol + Placebo caffeine; Placebo alcohol + Caffeine; or Placebo alcohol + Placebo caffeine. Accuracy, response time, and the amplitude of the N2 component of the event-related potential (ERP), a neural index of conflict monitoring, were examined as a function of whether or not conflict was present (i.e., whether or not flankers were compatible with the target) on both the previous trial and the current trial. Results Alcohol did not abolish conflict monitoring or adaptation. Caffeine eliminated conflict adaptation in sequential trials but also enhanced neural conflict monitoring. The combined effect of alcohol and caffeine was apparent only in how previous conflict affected the neural conflict monitoring response. Conclusions Together, the findings suggest that caffeine leads to exaggeration of attentional resource utilization, which could provide short-term benefits but lead to problems conserving resources for when they are most needed. PMID:26815360

  4. Effects of Caffeine on Olfactory Learning in Crickets.

    PubMed

    Sugimachi, Seigo; Matsumoto, Yukihisa; Mizunami, Makoto; Okada, Jiro

    2016-10-01

    Caffeine is a plant-derived alkaloid that is generally known as a central nervous system (CNS) stimulant. In order to examine the effects of caffeine on higher CNS functions in insects, we used an appetitive olfactory learning paradigm for the cricket Gryllus bimaculatus. Crickets can form significant long-term memories (LTMs) after repetitive training sessions, during which they associate a conditioned stimulus (CS: odor) with an unconditioned stimulus (US: reward). Administration of hemolymphal injections of caffeine established LTM after only single-trial conditioning over a wide range of caffeine dosages (1.6 µµg/kg to 39 mg/kg). We investigated the physiological mechanisms underlying this enhancement of olfactory learning performance pharmacologically, focusing on three major physiological roles of caffeine: 1) inhibition of phosphodiesterase (PDE), 2) agonism of ryanodine receptors, and 3) antagonism of adenosine receptors. Application of drugs relevant to these actions resulted in significant effects on LTM formation. These results suggest that externally applied caffeine enhances LTM formation in insect olfactory learning via multiple cellular mechanisms.

  5. The perspective of caffeine and caffeine derived compounds in therapy.

    PubMed

    Pohanka, M

    2015-01-01

    Caffeine (1,3,7-trimethylxanthine) is a plant secondary metabolite with a significant impact on multiple processes and regulatory pathways in the body. Though major part of the population meets caffeine via coffee, tea or chocolate, it has also an important role in pharmacology and it is used as a supplementary substance in medicaments. Currently, the ability of caffeine to ameliorate some neurodegenerative disorders is proved in some studies. This review describes basic data about caffeine including toxicity, pharmacokinetics, biological mechanism of the action, and metabolism. Beside this, promising applications of caffeine, new medicaments and derivatives are discussed. Relevant papers and inventions are depicted in the manuscript. Caffeine is a pharmacologically promising substance that deserves big consideration in the current research and development. The compound has several reasons to be an object of scientific interest and to be used for pharmacology purposes. Despite an extensive research for a long time, no significantly negative effects on human health were proved hence caffeine can be considered as a completely safe compound. The recent data about amelioration of neurodegenerative and other disorders are promising and deserving more work on the issue. ARTICLE HIGHLIGHTS: Caffeine is a purine alkaloid from plants and it has a broad use in current pharmacology. Caffeine is a competitive antagonist of neurotransmitter adenosine on adenosine receptors. The substance is added as a supplementary to drugs and food.Besides interfering on adenosine receptors, caffeine interacts with acetylcholinesterase, monoamine oxidase, phosphodiesterase, ryanodine receptors and others.Current research is devoted to the role of caffeine in neurodegenerative diseases and immunity alteration. New chemical compounds based on caffeine moiety are prepared (Tab. 4, Fig. 6, Ref. 149).

  6. Changes in the ambulatory activity and discriminative stimulus effects of psychostimulant drugs in rats chronically exposed to caffeine: effect of caffeine dose.

    PubMed

    Gasior, M; Jaszyna, M; Peters, J; Goldberg, S R

    2000-12-01

    Caffeine is a common psychoactive constituent of coffee, carbonated beverages, and over-the-counter medications. This study examined the effects of chronic caffeine exposure on the behavioral response to acute administrations of psychostimulant drugs on ambulatory activity and on the pharmacological characteristics of nicotine discrimination in rats. Rats were maintained continuously on caffeine added to the drinking water at a concentration of 0.25 or 1. 0 mg/ml that resulted in plasma caffeine concentrations ranging from 0.37 to 5.95 microg/ml. Rats maintained on tap water served as control groups. Exposure to the lower caffeine concentration (0.25 mg/ml) potentiated stimulatory effects of nicotine, amphetamine, and cocaine on ambulatory activity and failed to produce tolerance to the acute stimulatory effects of caffeine. In contrast, exposure to the higher caffeine concentration (1.0 mg/ml) did not alter the effects of the psychomotor stimulants on ambulatory behaviors but resulted in the development of complete, insurmountable tolerance to the acute stimulatory effects of caffeine. In the nicotine discrimination paradigm (0.4 mg/kg, training dose, a fixed-ratio 10 schedule of food delivery in a two-lever choice paradigm), rats exposed to the lower, but not to the higher, caffeine concentration acquired the nicotine discrimination significantly faster and were more sensitive to the effects of amphetamine and cocaine in substitution tests than water-drinking rats. Caffeine exposure did not change pharmacokinetic properties of nicotine (i.e., plasma levels, metabolism). In summary, exposure to two different caffeine solutions within a range of plasma levels observed in humans resulted in quantitatively distinct changes in psychostimulant-induced nonoperant and operant measures of behavior. These results suggest that dietary consumption of moderate doses of caffeine may be associated with enhanced reactions to some psychostimulants.

  7. Caffeine as an analgesic adjuvant for acute pain in adults.

    PubMed

    Derry, Christopher J; Derry, Sheena; Moore, R Andrew

    2012-03-14

    Caffeine has been added to common analgesics such as paracetamol, ibuprofen, and aspirin, in the belief that it enhances analgesic efficacy. Evidence to support this belief is limited and often based on invalid comparisons. To assess the relative efficacy in acute pain of a single dose of any analgesic plus caffeine against the same dose of analgesic alone. We searched CENTRAL, MEDLINE, EMBASE, and the Oxford Pain Relief Database to January 2012, and also carried out Internet searches and contacted pharmaceutical companies known to have carried out trials that have not been published. We included randomised, double-blind studies that compared a single dose of analgesic plus caffeine with the same dose of the analgesic alone in the treatment of acute pain. Two review authors independently assessed eligibility and quality of studies, and extracted data. Any disagreements or uncertainties were settled by discussion with a third review author. We sought any validated measure of analgesic efficacy, but particularly the number of participants experiencing at least 50% of the maximum possible pain relief over four to six hours, participants reporting a global evaluation of treatment of very good or excellent, or headache relief after two hours. We pooled comparable data to look for a statistically significant difference, and calculated numbers needed to treat to benefit (NNT) with caffeine. We also looked for any numerical superiority associated with the addition of caffeine, and information about any serious adverse events. We identified 19 studies (7238 participants) in valid comparisons. Most studies used paracetamol or ibuprofen, with 100 mg to 130 mg caffeine, and the most common pain conditions studied were postoperative dental pain, postpartum pain, and headache. There was a small but statistically significant benefit with caffeine used at doses of 100 mg or more, which was not dependent on the pain condition or type of analgesic. About 5% to 10% more participants

  8. Adolescent caffeine consumption increases adulthood anxiety-related behavior and modifies neuroendocrine signaling

    PubMed Central

    O’Neill, Casey E.; Newsom, Ryan J.; Stafford, Jacob; Scott, Talia; Archuleta, Solana; Levis, Sophia C.; Spencer, Robert L.; Campeau, Serge; Bachtell, Ryan K.

    2016-01-01

    Caffeine is a commonly used psychoactive substance and consumption by children and adolescents continues to rise. Here, we examine the lasting effects of adolescent caffeine consumption on anxiety-related behaviors and several neuroendocrine measures in adulthood. Adolescent male Sprague-Dawley rats consumed caffeine (0.3 g/L) for 28 consecutive days from postnatal day 28 (P28) to P55. Age-matched control rats consumed water. Behavioral testing for anxiety-related behavior began in adulthood (P62) 7 days after removal of caffeine. Adolescent caffeine consumption enhanced anxiety-related behavior in an open field, social interaction test, and elevated plus maze. Similar caffeine consumption in adult rats did not alter anxiety-related behavior after caffeine removal. Characterization of neuroendocrine measures was next assessed to determine whether the changes in anxiety were associated with modifications in the HPA axis. Blood plasma levels of corticosterone (CORT) were assessed throughout the caffeine consumption procedure in adolescent rats. Adolescent caffeine consumption elevated plasma CORT 24 h after initiation of caffeine consumption that normalized over the course of the 28-day consumption procedure. CORT levels were also elevated 24 h after caffeine removal and remained elevated for 7 days. Despite elevated basal CORT in adult rats that consumed caffeine during adolescence, the adrenocorticotropic hormone (ACTH) and CORT response to placement on an elevated pedestal (a mild stressor) was significantly blunted. Lastly, we assessed changes in basal and stress-induced c-fos and corticotropin-releasing factor (Crf) mRNA expression in brain tissue collected at 7 days withdrawal from adolescent caffeine. Adolescent caffeine consumption increased basal c-fos mRNA in the paraventricular nucleus of the hypothalamus. Adolescent caffeine consumption had no other effects on the basal or stress-induced c-fos mRNA changes. Caffeine consumption during adolescence

  9. Adolescent caffeine consumption increases adulthood anxiety-related behavior and modifies neuroendocrine signaling.

    PubMed

    O'Neill, Casey E; Newsom, Ryan J; Stafford, Jacob; Scott, Talia; Archuleta, Solana; Levis, Sophia C; Spencer, Robert L; Campeau, Serge; Bachtell, Ryan K

    2016-05-01

    Caffeine is a commonly used psychoactive substance and consumption by children and adolescents continues to rise. Here, we examine the lasting effects of adolescent caffeine consumption on anxiety-related behaviors and several neuroendocrine measures in adulthood. Adolescent male Sprague-Dawley rats consumed caffeine (0.3g/L) for 28 consecutive days from postnatal day 28 (P28) to P55. Age-matched control rats consumed water. Behavioral testing for anxiety-related behavior began in adulthood (P62) 7 days after removal of caffeine. Adolescent caffeine consumption enhanced anxiety-related behavior in an open field, social interaction test, and elevated plus maze. Similar caffeine consumption in adult rats did not alter anxiety-related behavior after caffeine removal. Characterization of neuroendocrine measures was next assessed to determine whether the changes in anxiety were associated with modifications in the HPA axis. Blood plasma levels of corticosterone (CORT) were assessed throughout the caffeine consumption procedure in adolescent rats. Adolescent caffeine consumption elevated plasma CORT 24h after initiation of caffeine consumption that normalized over the course of the 28-day consumption procedure. CORT levels were also elevated 24h after caffeine removal and remained elevated for 7 days. Despite elevated basal CORT in adult rats that consumed caffeine during adolescence, the adrenocorticotropic hormone (ACTH) and CORT response to placement on an elevated pedestal (a mild stressor) was significantly blunted. Lastly, we assessed changes in basal and stress-induced c-fos and corticotropin-releasing factor (Crf) mRNA expression in brain tissue collected at 7 days withdrawal from adolescent caffeine. Adolescent caffeine consumption increased basal c-fos mRNA in the paraventricular nucleus of the hypothalamus. Adolescent caffeine consumption had no other effects on the basal or stress-induced c-fos mRNA changes. Caffeine consumption during adolescence increased

  10. Caffeine consumption in young children.

    PubMed

    Warzak, William J; Evans, Shelby; Floress, Margaret T; Gross, Amy C; Stoolman, Sharon

    2011-03-01

    Two hundred twenty-eight surveyed parents reported that their 5 to 7 year old children drank approximately 52 mg of caffeine daily and their 8 to 12 year old children drank 109 mg daily. Caffeine consumption and hours slept were significantly negatively correlated, but caffeine consumption and enuresis were not significantly correlated. Spanish-speaking parents reported fewer bedwetting events than their English-speaking peers.

  11. Caffeine and headache: specific remarks.

    PubMed

    Espinosa Jovel, C A; Sobrino Mejía, F E

    Caffeine is the most widely used psychostimulant worldwide. Excessive caffeine consumption induces a series of both acute and chronic biological and physiological changes that may give rise to cognitive decline, depression, fatigue, insomnia, cardiovascular changes, and headache. Chronic consumption of caffeine promotes a pro-nociceptive state of cortical hyperexcitability that can intensify a primary headache or trigger a headache due to excessive analgesic use. This review offers an in-depth analysis of the physiological mechanisms of caffeine and its relationship with headache. Copyright © 2014 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

  12. [Side effects of caffeine].

    PubMed

    Dworzański, Wojciech; Opielak, Grzegorz; Burdan, Franciszek

    2009-11-01

    Caffeine is one of the most commonly ingested alkaloids worldwide. It is present in coffee, tea, soft and energy drinks, chocolate, etc. Currently published data has been stressed that the metyloxantine consumption increases the risk of coronary heart disease, arterial hypertension, arterial stiffness, and an elevation of cholesterol and homocysteine plasma concentration. The acute high consumption may also modulate insulin sensitivity and glucose blood level. However, the long-term consumption reduces the incidence of the type 2 diabetes mellitus. When administered in high doses the substance may cause various side effects, related to abnormal stimulation of the central nervous system, decrease tonus of the lower esophageal sphincter, as well as increase risk of miscarriage and intrauterine growth retardation. The final manifestation of side reactions is dependent on the genotype, especially polymorphisms of genes associated with caffeine metabolism, i.e., cytochrome P450-CYP1A2 and catechol-O-methyltransferase (COMT).

  13. Histone H3 K27 acetylation marks a potent enhancer element on the adipogenic master regulator gene Pparg2

    PubMed Central

    Ramlee, Muhammad Khairul; Zhang, Qiongyi; Idris, Muhammad; Peng, Xu; Sim, Choon Kiat; Han, Weiping; Xu, Feng

    2014-01-01

    PPARγ2 is expressed almost exclusively in adipose tissue and plays a central role in adipogenesis. Despite intensive studies over the last 2 decades, the mechanism regulating the expression of the Pparg2 gene, especially the role of cis-regulatory elements, is still not completely understood. Here, we report a comprehensive investigation of the enhancer elements within the murine Pparg2 gene. Utilizing the combined techniques of sequence conservation analysis and chromatin marker examination, we identified a potent enhancer element that augmented the expression of a reporter gene under the control of the Pparg2 promoter by 20-fold. This enhancer element was first identified as highly conserved non-coding sequence 10 (CNS10) and was later shown to be enriched with the enhancer marker H3 K27 acetylation. Further studies identified a binding site for p300 as the essential enhancer element in CNS10. Moreover, p300 physically binds to CNS10 and is required for the enhancer activity of CNS10. The depletion of p300 by siRNA resulted in significantly impaired activation of Pparg2 at the early stages of 3T3-L1 adipogenesis. In summary, our study identified a novel enhancer element on the murine Pparg2 gene and suggested a novel mechanism for the regulation of Pparg2 expression by p300 in 3T3-L1 adipogenesis. PMID:25485585

  14. Histone H3 K27 acetylation marks a potent enhancer element on the adipogenic master regulator gene Pparg2.

    PubMed

    Ramlee, Muhammad Khairul; Zhang, Qiongyi; Idris, Muhammad; Peng, Xu; Sim, Choon Kiat; Han, Weiping; Xu, Feng

    2014-01-01

    PPARγ2 is expressed almost exclusively in adipose tissue and plays a central role in adipogenesis. Despite intensive studies over the last 2 decades, the mechanism regulating the expression of the Pparg2 gene, especially the role of cis-regulatory elements, is still not completely understood. Here, we report a comprehensive investigation of the enhancer elements within the murine Pparg2 gene. Utilizing the combined techniques of sequence conservation analysis and chromatin marker examination, we identified a potent enhancer element that augmented the expression of a reporter gene under the control of the Pparg2 promoter by 20-fold. This enhancer element was first identified as highly conserved non-coding sequence 10 (CNS10) and was later shown to be enriched with the enhancer marker H3 K27 acetylation. Further studies identified a binding site for p300 as the essential enhancer element in CNS10. Moreover, p300 physically binds to CNS10 and is required for the enhancer activity of CNS10. The depletion of p300 by siRNA resulted in significantly impaired activation of Pparg2 at the early stages of 3T3-L1 adipogenesis. In summary, our study identified a novel enhancer element on the murine Pparg2 gene and suggested a novel mechanism for the regulation of Pparg2 expression by p300 in 3T3-L1 adipogenesis.

  15. Dasatinib suppression of medulloblastoma survival and migration is markedly enhanced by combining treatment with the aurora kinase inhibitor AT9283.

    PubMed

    Petersen, William; Liu, Jingbo; Yuan, Liangping; Zhang, Hongying; Schneiderjan, Matthew; Cho, Yoon-Jae; MacDonald, Tobey J

    2014-11-01

    Medulloblastoma (MB) expresses Src kinase, while aurora kinase A overexpression correlates with poor survival. We thus investigated novel combination treatment with dasatinib and AT9283, inhibitors of Src and aurora kinase, respectively, on MB growth in vitro and in vivo. Treatment with each drug significantly reduced cell viability and combined treatment markedly potentiated this response. AT9283 induced p53 expression, autophagy, and G2/M cell-cycle arrest, while combined treatment induced S phase arrest. Dasatinib treatment caused tumor regression in vivo. Activated Src was detected in 44% MB analyzed. We conclude that further evaluation of this combination therapy for MB is highly warranted.

  16. Uneasy marks.

    PubMed

    Rublee, D

    1998-05-05

    Germany earned a reputation as a European nirvana, marked by a booming job market and generous health and social programs. Now, thanks to the high costs of rebuilding the former East Germany and other factors, national health programs face cutbacks. But just about everyone has a stake in guarding the status quo.

  17. Effects of blue light and caffeine on mood.

    PubMed

    Ekström, Johan G; Beaven, C Martyn

    2014-09-01

    Both short wavelength (blue) light and caffeine have been studied for their mood enhancing effects on humans. The ability of blue light to increase alertness, mood and cognitive function via non-image forming neuropathways has been suggested as a non-pharmacological countermeasure for depression across a range of occupational settings. This experimental study compared blue light and caffeine and aimed to test the effects of blue light/placebo (BLU), white light/240-mg caffeine (CAF), blue light/240-mg caffeine (BCAF) and white light/placebo (PLA), on mood. A randomised, controlled, crossover design study was used, in a convenience population of 20 healthy volunteers. The participants rated their mood on the Swedish Core Affect Scales (SCAS) prior to and after each experimental condition to assess the dimensions of valence and activation. There was a significant main effect of light (p = 0.009), and the combination of blue light and caffeine had clear positive effects on core effects (ES, ranging from 0.41 to 1.20) and global mood (ES, 0.61 ± 0.53). The benefits of the combination of blue light and caffeine should be further investigated across a range of applications due to the observed effects on the dimensions of arousal, valence and pleasant activation.

  18. The Effect of Caffeine on Radiocalcium Movement in Frog Sartorius

    PubMed Central

    Bianchi, C. P.

    1961-01-01

    Caffeine increases resting calcium influx approximately threefold in normally polarized and in potassium-depolarized fibers of frog sartorius muscles. It does not affect the transient rapid increase in calcium influx that occurs at the beginning of a potassium depolarization. Calcium outflux in Ringer's solution, in zero calcium Ringer's solution, and in zero calcium Ringer's solution plus 0.004 M EDTA is also markedly increased by caffeine. The increased outflux reaches a rate which is approximately the same as the increased calcium influx. One interpretation of the findings is that caffeine reduces the binding of calcium both in the membrane and in the myoplasm; this increases the "permeability" to calcium and the ionic activity of calcium in muscle. This interpretation is consistent with the view that the contractile state of muscle is dependent at least in part on the thermodynamic activity of calcium in the muscle fibers. PMID:19873537

  19. Effects of caffeine on persistence and reinstatement of nicotine-seeking behavior in rats: interaction with nicotine-associated cues

    PubMed Central

    Jernigan, Courtney

    2013-01-01

    Rationale Caffeine and nicotine are the most commonly co-used psychostimulants. However, it is still unclear whether caffeine exposure enhances nicotine-seeking behavior. Objective The present study examined the effects of caffeine on nicotine-seeking in rats trained to self-administer nicotine with and without presession administration of caffeine. Methods Male Sprague–Dawley rats were trained to intravenously self-administer nicotine (0.03 mg/kg/infusion, freebase) on a fixed ratio 5 schedule of reinforcement and associate a stimulus cue with each nicotine administration. Five minutes before the sessions, the rats received an intraperitoneal administration of caffeine (5 mg/kg). Extinction tests were conducted under four conditions: presession caffeine administration, response-contingent presentation of nicotine cues, neither condition, or both conditions. Reinstatement tests were conducted after responding was extinguished by withholding presession caffeine, nicotine, and its cues. A separate group of rats trained without presession caffeine exposure was also subjected to the reinstatement tests. Results In the rats trained with presession caffeine exposure, continued caffeine administration sustained nicotine-seeking responses and interacted with nicotine cues to significantly delay the extinction of nicotine-seeking behavior. Readministration of caffeine after extinction effectively reinstated nicotine-seeking behavior. In caffeine-naive rats, caffeine administration did not reinstate extinguished nicotine-seeking behavior but significantly potentiated the cue-induced reinstatement of nicotine-seeking. Conclusion These data demonstrate that caffeine administration sustained and reinstated nicotine-seeking behavior, possibly via its acquired discriminative-stimulus properties predictive of nicotine availability. These findings suggest that smokers who attempt to quit may benefit from stopping caffeine consumption. PMID:21947355

  20. Caffeine attenuates scopolamine-induced memory impairment in humans.

    PubMed

    Riedel, W; Hogervorst, E; Leboux, R; Verhey, F; van Praag, H; Jolles, J

    1995-11-01

    Caffeine consumption can be beneficial for cognitive functioning. Although caffeine is widely recognized as a mild CNS stimulant drug, the most important consequence of its adenosine antagonism is cholinergic stimulation, which might lead to improvement of higher cognitive functions, particularly memory. In this study, the scopolamine model of amnesia was used to test the cholinergic effects of caffeine, administered as three cups of coffee. Subjects were 16 healthy volunteers who received 250 mg caffeine and 2 mg nicotine separately, in a placebo-controlled double-blind cross-over design. Compared to placebo, nicotine attenuated the scopolamine-induced impairment of storage in short-term memory and attenuated the scopolamine-induced slowing of speed of short-term memory scanning. Nicotine also attenuated the scopolamine-induced slowing of reaction time in a response competition task. Caffeine attenuated the scopolamine-induced impairment of free recall from short- and long-term memory, quality and speed of retrieval from long-term memory in a word learning task, and other cognitive and non-cognitive measures, such as perceptual sensitivity in visual search, reading speed, and rate of finger-tapping. On the basis of these results it was concluded that caffeine possesses cholinergic cognition enhancing properties. Caffeine could be used as a control drug in studies using the scopolamine paradigm and possibly also in other experimental studies of cognitive enhancers, as the effects of a newly developed cognition enhancing drug should at least be superior to the effects of three cups of coffee.

  1. Effect of caffeine on radiation-induced mitotic delay: delayed expression of G/sub 2/ arrest

    SciTech Connect

    Rowley, R.; Zorch, M.; Leeper, D.B.

    1984-01-01

    In the presence of 5 mM caffeine, irradiated (1.5 Gy) S and G/sub 2/ cells progressed to mitosis in register and without arrest in G/sub 2/. Caffeine (5 mM) markedly reduced mitotic delay even after radiation doses up to 20 Gy. When caffeine was removed from irradiated (1.5 Gy) and caffeine-treated cells, a period of G/sub 2/ arrest followed, similar in length to that produced by radiation alone. The arrest expressed was independent of the duration of the caffeine treatment for exposures up to 3 hr. The similarity of the response to the cited effects of caffeine on S-phase delay suggests a common basis for delay induction in S and G/sub 2/ phases.

  2. Effect of caffeine on response of rabbit isolated corpus cavernosum to high K+ solution, noradrenaline and transmural electrical stimulation.

    PubMed

    Adebiyi, Adebowale; Adaikan, P Ganesan

    2004-01-01

    1. Caffeine has wide-ranging activities on smooth muscles, including contractile and relaxant effects. The aim of the present study was to examine the activity of caffeine on rabbit corpus cavernosum (RCC). 2. The effects of caffeine (0.5-4.0 mmol/L) on the response of RCC to high K+ solution, noradrenaline (NA) and transmural electrical stimulation (EFS) were studied in a tissue bath system. 3. Caffeine did not contract the RCC. However, 0.5-4.0 mmol/L caffeine caused concentration-dependent relaxation of tension development in high-K+ (120 mmol/L) solution in contrast with the solvent control. At 4.0 mmol/L caffeine, high-K+ solution-induced tone of the RCC was reduced by 73.4 +/- 7.3%. Caffeine (0.5-4.0 mmol/L) also concentration-dependently relaxed NA (12.5 micro mol/L)-induced tonic contraction of the RCC. At 4.0 mmol/L caffeine, NA-induced tone of the RCC was reduced by 41.1 +/- 7.0%. Incubation of RCC in 2.0 mmol/L caffeine for 30 min prior to EFS (1-40 Hz) caused a marked rightward shift in the frequency-response curve. 4. The results of the present study suggest that caffeine exhibits relaxant activity on rabbit cavernosal smooth muscle and the mechanism of this activity possibly involves inhibition of Ca2+ signalling.

  3. Caffeine provokes adverse interactions with 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') and related psychostimulants: mechanisms and mediators.

    PubMed

    Vanattou-Saïfoudine, N; McNamara, R; Harkin, A

    2012-11-01

    Concomitant consumption of caffeine with recreational psychostimulant drugs of abuse can provoke severe acute adverse reactions in addition to longer term consequences. The mechanisms by which caffeine increases the toxicity of psychostimulants include changes in body temperature regulation, cardiotoxicity and lowering of the seizure threshold. Caffeine also influences the stimulatory, discriminative and reinforcing effects of psychostimulant drugs. In this review, we consider our current understanding of such caffeine-related drug interactions, placing a particular emphasis on an adverse interaction between caffeine and the substituted amphetamine, 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy'), which has been most recently described and characterized. Co-administration of caffeine profoundly enhances the acute toxicity of MDMA in rats, as manifested by high core body temperature, tachycardia and increased mortality. In addition, co-administration of caffeine enhances the long-term serotonergic neurotoxicity induced by MDMA. Observations to date support an interactive model of drug-induced toxicity comprising MDMA-related enhancement of dopamine release coupled to a caffeine-mediated antagonism of adenosine receptors in addition to inhibition of PDE. These experiments are reviewed together with reports of caffeine-related drug interactions with cocaine, d-amphetamine and ephedrine where similar mechanisms are implicated. Understanding the underlying mechanisms will guide appropriate intervention strategies for the management of severe reactions and potential for increased drug-related toxicity, resulting from concomitant caffeine consumption. © 2012 The Authors. British Journal of Pharmacology © 2012 The British Pharmacological Society.

  4. Caffeine provokes adverse interactions with 3,4-methylenedioxymethamphetamine (MDMA, ‘ecstasy’) and related psychostimulants: mechanisms and mediators

    PubMed Central

    Vanattou-Saïfoudine, N; McNamara, R; Harkin, A

    2012-01-01

    Concomitant consumption of caffeine with recreational psychostimulant drugs of abuse can provoke severe acute adverse reactions in addition to longer term consequences. The mechanisms by which caffeine increases the toxicity of psychostimulants include changes in body temperature regulation, cardiotoxicity and lowering of the seizure threshold. Caffeine also influences the stimulatory, discriminative and reinforcing effects of psychostimulant drugs. In this review, we consider our current understanding of such caffeine-related drug interactions, placing a particular emphasis on an adverse interaction between caffeine and the substituted amphetamine, 3,4-methylenedioxymethamphetamine (MDMA, ‘ecstasy’), which has been most recently described and characterized. Co-administration of caffeine profoundly enhances the acute toxicity of MDMA in rats, as manifested by high core body temperature, tachycardia and increased mortality. In addition, co-administration of caffeine enhances the long-term serotonergic neurotoxicity induced by MDMA. Observations to date support an interactive model of drug-induced toxicity comprising MDMA-related enhancement of dopamine release coupled to a caffeine-mediated antagonism of adenosine receptors in addition to inhibition of PDE. These experiments are reviewed together with reports of caffeine-related drug interactions with cocaine, d-amphetamine and ephedrine where similar mechanisms are implicated. Understanding the underlying mechanisms will guide appropriate intervention strategies for the management of severe reactions and potential for increased drug-related toxicity, resulting from concomitant caffeine consumption. PMID:22671762

  5. Effect of caffeine supplementation on haematological and biochemical variables in elite soccer players under physical stress conditions

    PubMed Central

    Bassini‐Cameron, Adriana; Sweet, Eric; Bottino, Altamiro; Bittar, Christina; Veiga, Carlos; Cameron, Luiz‐Claudio

    2007-01-01

    Objective To evaluate the effect of caffeine on white cell distribution and muscle injury markers in professional soccer players during exercise. Methods 22 male athletes completed a placebo controlled double blind test protocol to simulate a soccer match, followed by a Yo‐Yo intermittent recovery test. Results Exercise caused an increase in packed cell volume that was enhanced by caffeine. Caffeine and exercise had a synergistic effect on the blood lymphocyte count, which increased by about 38% after exercise, and by an additional 35% when combined with caffeine. Caffeine promoted an exercise independent rise in circulating monocytes, and a synergistic action of exercise and caffeine was observed on segmented neutrophils. Caffeine promoted thrombocytosis. Plasma adenosine deaminase, aspartate aminotransferase, and lactate dehydrogenase concentrations were enhanced by exercise, and alanine transaminase concentration was enhanced in both groups, with a synergistic effect of caffeine. Conclusions The pronounced increase in the white cell count in the group receiving caffeine appeared to be caused by greater muscle stress and consequently more intense endothelial and muscle cell injury. The use of caffeine may augment the risk of muscle damage in athletes. PMID:17473001

  6. Caffeine increases striatal dopamine D2/D3 receptor availability in the human brain.

    PubMed

    Volkow, N D; Wang, G-J; Logan, J; Alexoff, D; Fowler, J S; Thanos, P K; Wong, C; Casado, V; Ferre, S; Tomasi, D

    2015-04-14

    Caffeine, the most widely consumed psychoactive substance in the world, is used to promote wakefulness and enhance alertness. Like other wake-promoting drugs (stimulants and modafinil), caffeine enhances dopamine (DA) signaling in the brain, which it does predominantly by antagonizing adenosine A2A receptors (A2AR). However, it is unclear if caffeine, at the doses consumed by humans, increases DA release or whether it modulates the functions of postsynaptic DA receptors through its interaction with adenosine receptors, which modulate them. We used positron emission tomography and [(11)C]raclopride (DA D2/D3 receptor radioligand sensitive to endogenous DA) to assess if caffeine increased DA release in striatum in 20 healthy controls. Caffeine (300 mg p.o.) significantly increased the availability of D2/D3 receptors in putamen and ventral striatum, but not in caudate, when compared with placebo. In addition, caffeine-induced increases in D2/D3 receptor availability in the ventral striatum were associated with caffeine-induced increases in alertness. Our findings indicate that in the human brain, caffeine, at doses typically consumed, increases the availability of DA D2/D3 receptors, which indicates that caffeine does not increase DA in the striatum for this would have decreased D2/D3 receptor availability. Instead, we interpret our findings to reflect an increase in D2/D3 receptor levels in striatum with caffeine (or changes in affinity). The association between increases in D2/D3 receptor availability in ventral striatum and alertness suggests that caffeine might enhance arousal, in part, by upregulating D2/D3 receptors.

  7. Caffeine increases striatal dopamine D2/D3 receptor availability in the human brain

    PubMed Central

    Volkow, N D; Wang, G-J; Logan, J; Alexoff, D; Fowler, J S; Thanos, P K; Wong, C; Casado, V; Ferre, S; Tomasi, D

    2015-01-01

    Caffeine, the most widely consumed psychoactive substance in the world, is used to promote wakefulness and enhance alertness. Like other wake-promoting drugs (stimulants and modafinil), caffeine enhances dopamine (DA) signaling in the brain, which it does predominantly by antagonizing adenosine A2A receptors (A2AR). However, it is unclear if caffeine, at the doses consumed by humans, increases DA release or whether it modulates the functions of postsynaptic DA receptors through its interaction with adenosine receptors, which modulate them. We used positron emission tomography and [11C]raclopride (DA D2/D3 receptor radioligand sensitive to endogenous DA) to assess if caffeine increased DA release in striatum in 20 healthy controls. Caffeine (300 mg p.o.) significantly increased the availability of D2/D3 receptors in putamen and ventral striatum, but not in caudate, when compared with placebo. In addition, caffeine-induced increases in D2/D3 receptor availability in the ventral striatum were associated with caffeine-induced increases in alertness. Our findings indicate that in the human brain, caffeine, at doses typically consumed, increases the availability of DA D2/D3 receptors, which indicates that caffeine does not increase DA in the striatum for this would have decreased D2/D3 receptor availability. Instead, we interpret our findings to reflect an increase in D2/D3 receptor levels in striatum with caffeine (or changes in affinity). The association between increases in D2/D3 receptor availability in ventral striatum and alertness suggests that caffeine might enhance arousal, in part, by upregulating D2/D3 receptors. PMID:25871974

  8. Caffeine increases striatal dopamine D2/D3 receptor availability in the human brain

    DOE PAGES

    Volkow, N. D.; Wang, G. -J.; Logan, J.; ...

    2015-04-14

    Caffeine, the most widely consumed psychoactive substance in the world, is used to promote wakefulness and enhance alertness. Like other wake-promoting drugs (stimulants and modafinil), caffeine enhances dopamine (DA) signaling in the brain, which it does predominantly by antagonizing adenosine A2A receptors (A2AR). However, it is unclear if caffeine, at the doses consumed by humans, increases DA release or whether it modulates the functions of postsynaptic DA receptors through its interaction with adenosine receptors, which modulate them. We used positron emission tomography and [11C]raclopride (DA D2/D3 receptor radioligand sensitive to endogenous DA) to assess if caffeine increased DA release inmore » striatum in 20 healthy controls. Caffeine (300mg p.o.) significantly increased the availability of D2/D3 receptors in putamen and ventral striatum, but not in caudate, when compared with placebo. In addition, caffeine-induced increases in D2/D3 receptor availability in the ventral striatum were associated with caffeine-induced increases in alertness. Our findings indicate that in the human brain, caffeine, at doses typically consumed, increases the availability of DA D2/D3 receptors, which indicates that caffeine does not increase DA in the striatum for this would have decreased D2/D3 receptor availability. Instead, we interpret our findings to reflect an increase in D2/D3 receptor levels in striatum with caffeine (or changes in affinity). Furthermore, the association between increases in D2/D3 receptor availability in ventral striatum and alertness suggests that caffeine might enhance arousal, in part, by upregulating D2/D3 receptors.« less

  9. Caffeine attenuated ER stress-induced leptin resistance in neurons.

    PubMed

    Hosoi, Toru; Toyoda, Keisuke; Nakatsu, Kanako; Ozawa, Koichiro

    2014-05-21

    Exposing the endoplasmic reticulum (ER) to stress causes the accumulation of unfolded proteins, and subsequently results in ER stress. ER stress may be involved in various disorders such as obesity, diabetes, and neurodegenerative diseases. Leptin is an important circulating hormone, that inhibits food intake and accelerates energy consumption, which suppresses body weight gain. Recent studies demonstrated that leptin resistance is one of the main factors involved in the development of obesity. We and other groups recently reported the role of ER stress in the development of leptin resistance. Therefore, identifying drugs that target ER stress may be a promising fundamental strategy for the treatment of obesity. In the present study, we investigated whether caffeine could affect ER stress and the subsequent development of leptin resistance. We showed that caffeine exhibited chaperone activity, which attenuated protein aggregation. Caffeine also inhibited the ER stress-induced activation of IRE1 and PERK, which suggested the attenuation of ER stress. Moreover, caffeine markedly improved ER stress-induced impairments in the leptin-induced phosphorylation of STAT3. Therefore, these results suggest caffeine may have pharmacological properties that ameliorate leptin resistance by reducing ER stress.

  10. Effect of melatonin and caffeine interaction on caffeine induced oxidative stress and sleep disorders.

    PubMed

    Obochi, G O; Amali, O O E; Ochalefu, D O

    2010-11-24

    Effect of interaction of melatonin and caffeine on caffeine induced oxidative stress and sleep disorders was studied. Fifteen wistar rats were randomly assigned into three study groups. The animals in group 1 (the control) received a placebo of 10.0 ml distilled water via gastric intubation. The hosts in groups 2 and 3 were treated with 100 mg caffeine/ kg, or melatonin/ kg, respectively, in a total volume of 10.0 ml vehicle. The experiment lasted for 30 days. One day after the final exposure, the animals were euthanized by inhalation of overdose of chloroform. Blood was collected by cardiac puncture. Serum was obtained by centrifugation (6000 Xg, 30 mins), and used for serum total protein and serum blood urea nitrogen levels. The brain of each rat was also harvested and processed into whole homogenate, frozen in liquid nitrogen (N2), and maintained at -80oC until used for total brain cholesterol and tryptophan levels. The results showed that interaction of melatonin and caffeine enhanced protein synthesis; stimulated gonadotrophin release,  and could be used as oral contraceptive for women, and may be beneficial in the treatment of impotence (androgen depression), leading to improved reproductive and sex life; stimulated tryptophan metabolism, which prevents vitamin B6 deficiency, anemia, negative nitrogen balance, tissue wasting and accumulation of xanthurenic acid, which promotes sleep; and could be beneficial in the treatment of hyper cholesterolemia, thereby preventing coronary heart disease, and post menopausal osteoporosis.

  11. Efficacy of acute caffeine ingestion for short-term high-intensity exercise performance: a systematic review.

    PubMed

    Astorino, Todd A; Roberson, Daniel W

    2010-01-01

    Caffeine is the most widely used drug in the world, commonly ingested in coffee, tea, soda, and energy drinks. Its ability to enhance muscular work has been apparent since the early 1900s. Caffeine typically increases endurance performance; however, efficacy of caffeine ingestion for short-term high-intensity exercise is equivocal, which may be explained by discrepancies in exercise protocols, dosing, and subjects' training status and habitual caffeine intake found across studies. The primary aim of this review is to critically examine studies that have tested caffeine's ability to augment performance during exercise dependent on nonoxidative metabolism such as sprinting, team sports, and resistance training. A review of the literature revealed 29 studies that measured alterations in short-term performance after caffeine ingestion. Each study was critically analyzed using the Physiotherapy Evidence Database (PEDro) scale. The mean PEDro score was 7.76 +/- 0.87. Eleven of 17 studies revealed significant improvements in team sports exercise and power-based sports with caffeine ingestion, yet these effects were more common in elite athletes who do not regularly ingest caffeine. Six of 11 studies revealed significant benefits of caffeine for resistance training. Some studies show decreased performance with caffeine ingestion when repeated bouts are completed. The exact mechanism explaining the ergogenic effect of caffeine for short-term exercise is unknown.

  12. Caffeine to Sustain Operational Fatigue

    DTIC Science & Technology

    2000-03-01

    It Caffeine is the most widely used psychostimulant and provided data about the most commonly used may be useful in operational fatigue-coping...palpitation, psychomotor agitation. Caffeine candy 05 withdrawal may cause headache, fatigue, anxiety, soda 04 insomnia, nausea, performance impainnents. snuff

  13. Consumption of dietary caffeine and coffee in physically active populations: physiological interactions.

    PubMed

    Tunnicliffe, Jasmine M; Erdman, Kelly Anne; Reimer, Raylene A; Lun, Victor; Shearer, Jane

    2008-12-01

    Caffeine is a proven ergogenic aid, increasing athletic performance, endurance, and mental chronometry at doses as low as 1-3 mg.kg-1. As coffee is a readily available and commonly ingested form of caffeine, the two are often equated. However, coffee also contains hundreds of other biologically active compounds, many of which are metabolically distinct from caffeine. The purpose of this review was to examine the prevalence of coffee and (or) caffeine consumption among elite Canadian athletes, and to delineate the effects of coffee and caffeine on physical activity, weight maintenance, performance, and metabolism. A total of 270 self-reported 3-day food records were examined for caffeine intake from athletes registered with Canadian Sport Centres in 2005 and 2006. Athletes ranged in age from 16-45 years, and competed in 38 different sports. Results showed that 30% of athletes ingested >1 mg.kg-1.day-1 from a variety of sources. Average daily intake was 0.85 +/- 13 mg.kg-1. Caffeine intake was not correlated with any 1 sport; the 10 highest caffeine users were athletes from 9 different sports, including skill, endurance, and power sports. No differences were noted for average caffeine ingestion between summer and winter sports. High caffeine intakes corresponded to coffee ingestion, with the 25 highest individual intakes (193-895 mg.day-1) from coffee drinkers. In summary, it can be concluded that the majority of high-level Canadian athletes consume dietary caffeine primarily in the form of coffee. However, levels consumed are insufficient to elicit performance enhancement. Potential detrimental effects of caffeine consumption on exercise performance include gastric upset, withdrawal, sleep disturbance, and interactions with other dietary supplements.

  14. Effects of a single, oral 60 mg caffeine dose on attention in healthy adult subjects.

    PubMed

    Wilhelmus, Micha Mm; Hay, Justin L; Zuiker, Rob Gja; Okkerse, Pieter; Perdrieu, Christelle; Sauser, Julien; Beaumont, Maurice; Schmitt, Jeroen; van Gerven, Joop Ma; Silber, Beata Y

    2017-02-01

    Caffeine induces positive effects on sustained attention, although studies assessing the acute effects of low caffeine dose (<75 mg) on sustained attention are limited and use short-term tests. Therefore, we investigated the acute effects of a 60 mg dose of caffeine on sustained attention in tests lasting up to 45 minutes using 82 low or non-caffeine-consuming healthy male ( n=41) and female ( n=41) adults aged between 40 and 60 years. Vigilance was measured using Mackworth Clock test, Rapid Visual Information Processing Test, adaptive tracking test, saccadic eye movement and attention switch test. Effects on mood and fatigue were analysed using Bond and Lader and Caffeine Research visual analogue scales, and Samn-Perelli questionnaire. Saliva sampling was performed for both compliance and caffeine pharmacokinetic analysis. Administration of a 60 mg caffeine dose resulted in a significant improvement in sustained attention compared with the placebo. Also a significantly improved peak saccadic velocity and reaction time performance was found, and decreased error rate. Significantly increased feelings of alertness, contentment and overall mood after caffeine treatment compared with placebo were observed. This study demonstrated that in healthy adult subjects oral administration of a single 60 mg caffeine dose elicited a clear enhancement of sustained attention and alertness, measured both in multiple objective performances and in subjective scales.

  15. The health consequences of caffeine.

    PubMed

    Curatolo, P W; Robertson, D

    1983-05-01

    Acutely administered caffeine modestly increases blood pressure, plasma catecholamine levels, plasma renin activity, serum free fatty acid levels, urine production, and gastric acid secretion. It alters the electroencephalographic spectrum, mood, and sleep patterns of normal volunteers. Chronic caffeine consumption has no effect on blood pressure, plasma catecholamine levels, plasma renin activity, serum cholesterol concentration, blood glucose levels, or urine production. Caffeine does not appear to be useful for increasing the motility of hypomotile sperm in artificial insemination or in the therapy of minimal brain dysfunction, cancer, or Parkinson's syndrome, but it may be effective as a topical treatment of atopic dermatitis and as systemic therapy for neonatal apnea. Caffeine does not seem to be associated with myocardial infarction; lower urinary tract, renal, or pancreatic cancer; teratogenicity; or fibrocystic breast disease. The role of caffeine in the production of cardiac arrhythmias or gastric or duodenal ulcers remains uncertain.

  16. Caffeine, diabetes, cognition, and dementia.

    PubMed

    Biessels, Geert Jan

    2010-01-01

    People with diabetes mellitus are at increased risk of cognitive dysfunction. This review explores the relation between caffeine intake, diabetes, cognition and dementia, focusing on type 2 diabetes (T2DM). Epidemiological studies on caffeine/coffee intake and T2DM risk are reviewed. Next, the impact of T2DM on cognition is addressed. Finally, the potential for caffeine to modulate the risk of cognitive decline in the context of diabetes is explored. The conclusion is that, although epidemiological studies indicate that coffee/caffeine consumption is associated with a decreased risk of T2DM and possibly also with a decreased dementia risk, we can at present not be certain that these associations are causal. For now, recommendations for coffee consumption in individuals with T2DM or pre-diabetic stages are therefore difficult to establish, but it should be acknowledged that caffeine does appear to have several properties that warrant further investigations in this field.

  17. Treatment of cardiovascular collapse from caffeine overdose with lidocaine, phenylephrine, and hemodialysis.

    PubMed

    Kapur, Rahi; Smith, Michael D

    2009-02-01

    Caffeine overdoses produce multiple symptoms, most of which are commonly associated with a marked increase in adrenergic tone. These can include hypertension, tachycardia, dysrhythmias, and central nervous and skeletal muscle stimulation. This case illustrates a massive caffeine ingestion with resultant cardiovascular collapse. The patient was stabilized with a combination of lidocaine and phenylephrine in the emergency department and underwent hemodialysis in the intensive care unit, with rapid extubation and return to baseline functioning. To our knowledge, this combination has not been previously used to treat massive caffeine ingestions.

  18. The Effects of Caffeine on Athletic Performance

    ERIC Educational Resources Information Center

    McDaniel, Larry W.; McIntire, Kyle; Streitz, Carmyn; Jackson, Allen; Gaudet, Laura

    2010-01-01

    Athletes who use caffeine before exercising or competition may be upgrading themselves more than they realize. Caffeine is classified as a stimulant and is the most commonly used drug in the world. Caffeine has the same affects that amphetamines and cocaine have, just to a lesser degree. Caffeine crosses the membranes of all the body's tissues. It…

  19. Perceived consequences of drinking caffeinated beverages.

    PubMed

    Page, R M

    1987-12-01

    A survey of 238 college students indicated that those who prefer to drink caffeine containing drinks maintain different perceptions about the negative and positive consequences of drinking caffeinated drinks from those who do not prefer to drink caffeinated drinks. 154 of the students reported that the last soft drink they consumed was caffeinated.

  20. The Effects of Caffeine on Athletic Performance

    ERIC Educational Resources Information Center

    McDaniel, Larry W.; McIntire, Kyle; Streitz, Carmyn; Jackson, Allen; Gaudet, Laura

    2010-01-01

    Athletes who use caffeine before exercising or competition may be upgrading themselves more than they realize. Caffeine is classified as a stimulant and is the most commonly used drug in the world. Caffeine has the same affects that amphetamines and cocaine have, just to a lesser degree. Caffeine crosses the membranes of all the body's tissues. It…

  1. Caffeine promotes ethanol drinking in rats. Examination using a limited-access free choice paradigm.

    PubMed

    Kunin, D; Gaskin, S; Rogan, F; Smith, B R; Amit, Z

    2000-07-01

    There is growing evidence that caffeine may alter the pattern of intake of a variety of drugs. The present study was designed to assess the effect of caffeine pretreatment on voluntary ethanol consumption. The first experiment examined the effect of caffeine on the acquisition of ethanol intake in a limited-access-choice procedure in which water and ethanol were presented concurrently. Male Wistar rats, exposed to food and water ad lib, were presented with a daily 1-h choice session between water and progressively increasing concentrations of ethanol (2-10%). Each ethanol concentration was made available for 4-6 days for a total of 20 days of access to ethanol. Intraperitoneal injections of caffeine (5 or 10 mg/kg) or saline were administered to the rats 30 min prior to each choice session. Caffeine produced a dose-related facilitation in ethanol drinking whereby the lower caffeine dose produced enhancement in ethanol drinking. The second experiment examined the effect of caffeine on the maintenance of established ethanol consumption. Male Wistar rats, initially acclimatized to increasing concentrations of ethanol (2%-10), were presented with an additional 18 ethanol (10%) presentations, comprised of a 6-day baseline period followed by 6 days of treatment where animals were given one of three doses of caffeine (2.5, 5 or 10 mg/kg) or saline prior to ethanol presentation. A final 6-day post-treatment period followed treatment. These results revealed an inverted-U effect of caffeine dose on ethanol ingestion where the low and high caffeine doses produced no effect but the moderate dose of 5 mg/kg enhanced ethanol drinking that persisted throughout the post-treatment period. A third experiment revealed that caffeine did not alter levels of blood ethanol within the time period used for the ethanol drinking session.

  2. Differences in the effect of chronic and acute caffeine on self-administration of cocaine in mice.

    PubMed

    Kuzmin, A; Johansson, B; Semenova, S; Fredholm, B B

    2000-08-01

    We have compared the ability of an acute injection of caffeine (3 mg/kg, i.p.) and long-term peroral caffeine consumption for 10 days ( approximately 150 mg/kg/day in tap water) to affect cocaine self-administration in mice. The peak plasma and brain levels of caffeine and its metabolites were similar in the two experimental set-ups. Moreover, the levels reached are close to those obtained in humans upon coffee ingestion. Neither type of caffeine administration affected the reinforcing effect of cocaine, defined as a selective increase in nose-poke responses in mice self-administering cocaine compared to their yoked controls. However, caffeine injection increased the amount of cocaine self-administered whereas caffeine drinking reduced it. A low dose of cocaine, by itself essentially ineffective, produced an increase in c-fos and NGFI-A mRNA in the cerebral cortex in mice that had been drinking caffeine. An acute caffeine injection also enhanced the immediate early gene response to cocaine, but to a lesser degree. Cocaine and caffeine also synergistically increased NGFI-A expression in caudate-putamen. Thus, regular caffeine drinking decreased the cocaine intake without significantly affecting its reinforcing properties, perhaps because it enhanced the activation of the predominantly inhibitory frontal cortical areas produced by low doses of cocaine.

  3. Electrodeposited nitrogen-doped graphene/carbon nanotubes nanocomposite as enhancer for simultaneous and sensitive voltammetric determination of caffeine and vanillin.

    PubMed

    Jiang, Lin; Ding, Yaping; Jiang, Feng; Li, Li; Mo, Fan

    2014-06-23

    A nitrogen-doped graphene/carbon nanotubes (NGR-NCNTs) nanocomposite was employed into the study of the electrochemical sensor via electrodeposition for the first time. The morphology and structure of NGR-NCNTs nanocomposite were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. Meanwhile, the electrochemical performance of the glassy carbon electrode (GCE) modified with electrodeposited NGR-NCNTs (ENGR-NCNTs/GCE) towards caffeine (CAF) and vanillin (VAN) determination was demonstrated by cyclic voltammetry (CV) and square wave voltammetry (SWV). Under optimal condition, ENGR-NCNTs/GCE exhibited a wide linearity of 0.06-50 μM for CAF and 0.01-10 μM for VAN with detection limits of 0.02 μM and 3.3×10(-3) μM, respectively. Furthermore, the application of the proposed sensor in food products was proven to be practical and reliable. The desirable results show that the ENGR-NCNTs nanocomposite has promising potential in electrocatalytic biosensor application. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Do energy drinks contain active components other than caffeine?

    PubMed

    McLellan, Tom M; Lieberman, Harris R

    2012-12-01

    Energy drinks (EDs) contain caffeine and are a new, popular category of beverage. It has been suggested that EDs enhance physical and cognitive performance; however, it is unclear whether the claimed benefits are attributable to components other than caffeine. A typical 235 mL ED provides between 40 and 250 mg of caffeine, equating to doses that improve cognitive and, at the higher levels, physical performance. EDs often contain taurine, guaraná, ginseng, glucuronolactone, B-vitamins, and other compounds. A literature search using PubMed, Psych Info, and Google Scholar identified 32 articles that examined the effects of ED ingredients alone and/or in combination with caffeine on physical or cognitive performance. A systematic evaluation of the evidence-based findings in these articles was then conducted. With the exception of some weak evidence for glucose and guaraná extract, there is an overwhelming lack of evidence to substantiate claims that components of EDs, other than caffeine, contribute to the enhancement of physical or cognitive performance. Additional well-designed, randomized, placebo-controlled studies replicated across laboratories are needed in order to assess claims made for these products. © 2012 International Life Sciences Institute.

  5. Hydrophobic Mutagenesis and Semi-rational Engineering of Arginine Deiminase for Markedly Enhanced Stability and Catalytic Efficiency.

    PubMed

    Jamil, Serwanja; Liu, Meng-Han; Liu, Yong-Mei; Han, Rui-Zhi; Xu, Guo-Chao; Ni, Ye

    2015-07-01

    Due to its systemic arginine degradation, arginine deiminase (ADI) has attracted attentions as an anti-tumor drug. Its low activity at physiological conditions among other limitations has necessitated its engineering for improved properties. The present study describes the hydrophobic mutagenesis and semi-rational engineering of ADI from Pseudomonas plecoglossicida (PpADI). Using an improved ADI variant M13 (D38H/A128T/E296K/H404R/I410L) as parent, site saturation mutagenesis at position 162 resulted in an over 20 % increase in protein solubility. Compared with M13 (15.23 U/mg), mutants M13-2 (M13+S245D) and M13-5 (M13+R243L) exhibited enhanced specific activity of 21.19 and 31.20 U/mg at physiological conditions. M13-5 displayed enhanced substrate specificity with a dramatic reduction in its K m value (from 0.52 to 0.16 mM). It is speculated that the improvements in M13-5 could mainly be attributed to the enhanced structural stability due to an R243L substitution. The hydrophobic contribution of Leu 243 was supported by mutant M13-9 (M13+A276W) generated based on the hydrophobic mutagenesis concept. M13-9 showed a specific activity of 18.68 U/mg, as well as remarkable thermal and pH stability. It retained over 90 % activity over pH range from 4.5 to 8.5. At 60 °C, the half-life of M13-9 was enhanced from 4 to 17.5 min in comparison with M13, and its specific activity at 62 °C (93.0 U/mg) was approximately fivefold of that determined at 37 °C. Our results suggest that the increased hydrophobicity around the active regions of PpADI might be crucial in improving its structural stability and ultimately catalytic efficiency.

  6. Caffeine modulates attention network function.

    PubMed

    Brunyé, Tad T; Mahoney, Caroline R; Lieberman, Harris R; Taylor, Holly A

    2010-03-01

    The present work investigated the effects of caffeine (0mg, 100mg, 200mg, 400mg) on a flanker task designed to test Posner's three visual attention network functions: alerting, orienting, and executive control [Posner, M. I. (2004). Cognitive neuroscience of attention. New York, NY: Guilford Press]. In a placebo-controlled, double-blind study using a repeated-measures design, we found that the effects of caffeine on visual attention vary as a function of dose and the attention network under examination. Caffeine improved alerting and executive control function in a dose-response manner, asymptoting at 200mg; this effect is congruent with caffeine's adenosine-mediated effects on dopamine-rich areas of brain, and the involvement of these areas in alerting and the executive control of visual attention. Higher doses of caffeine also led to a marginally less efficient allocation of visual attention towards cued regions during task performance (i.e., orienting). Taken together, results of this study demonstrate that caffeine has differential effects on visual attention networks as a function of dose, and such effects have implications for hypothesized interactions of caffeine, adenosine and dopamine in brain areas mediating visual attention. Published by Elsevier Inc.

  7. The effect of caffeine on working memory load-related brain activation in middle-aged males.

    PubMed

    Klaassen, Elissa B; de Groot, Renate H M; Evers, Elisabeth A T; Snel, Jan; Veerman, Enno C I; Ligtenberg, Antoon J M; Jolles, Jelle; Veltman, Dick J

    2013-01-01

    Caffeine is commonly consumed in an effort to enhance cognitive performance. However, little is known about the usefulness of caffeine with regard to memory enhancement, with previous studies showing inconsistent effects on memory performance. We aimed to determine the effect of caffeine on working memory (WM) load-related activation during encoding, maintenance and retrieval phases of a WM maintenance task using functional magnetic resonance imaging (fMRI). 20 healthy, male, habitual caffeine consumers aged 40-61 years were administered 100 mg of caffeine in a double-blind placebo-controlled crossover design. Participants were scanned in a non-withdrawn state following a workday during which caffeinated products were consumed according to individual normal use (range = 145-595 mg). Acute caffeine administration was associated with increased load-related activation compared to placebo in the left and right dorsolateral prefrontal cortex during WM encoding, but decreased load-related activation in the left thalamus during WM maintenance. These findings are indicative of an effect of caffeine on the fronto-parietal network involved in the top-down cognitive control of WM processes during encoding and an effect on the prefrontal cortico-thalamic loop involved in the interaction between arousal and the top-down control of attention during maintenance. Therefore, the effects of caffeine on WM may be attributed to both a direct effect of caffeine on WM processes, as well as an indirect effect on WM via arousal modulation. Behavioural and fMRI results were more consistent with a detrimental effect of caffeine on WM at higher levels of WM load, than caffeine-related WM enhancement. This article is part of a Special Issue entitled 'Cognitive Enhancers'.

  8. Caffeine synergizes with another coffee component to increase plasma GCSF: linkage to cognitive benefits in Alzheimer's mice.

    PubMed

    Cao, Chuanhai; Wang, Li; Lin, Xiaoyang; Mamcarz, Malgorzata; Zhang, Chi; Bai, Ge; Nong, Jasson; Sussman, Sam; Arendash, Gary

    2011-01-01

    Retrospective and prospective epidemiologic studies suggest that enhanced coffee/caffeine intake during aging reduces risk of Alzheimer's disease (AD). Underscoring this premise, our studies in AD transgenic mice show that long-term caffeine administration protects against cognitive impairment and reduces brain amyloid-β levels/deposition through suppression of both β- and γ-secretase. Because coffee contains many constituents in addition to caffeine that may provide cognitive benefits against AD, we examined effects of caffeinated and decaffeinated coffee on plasma cytokines, comparing their effects to caffeine alone. In both AβPPsw+PS1 transgenic mice and non-transgenic littermates, acute i.p. treatment with caffeinated coffee greatly and specifically increased plasma levels of granulocyte-colony stimulating factor (GCSF), IL-10, and IL-6. Neither caffeine solution alone (which provided high plasma caffeine levels) or decaffeinated coffee provided this effect, indicating that caffeine synergized with some as yet unidentified component of coffee to selectively elevate these three plasma cytokines. The increase in GCSF is particularly important because long-term treatment with coffee (but not decaffeinated coffee) enhanced working memory in a fashion that was associated only with increased plasma GCSF levels among all cytokines. Since we have previously reported that long-term GCSF treatment enhances cognitive performance in AD mice through three possible mechanisms (e.g., recruitment of microglia from bone marrow, synaptogenesis, and neurogenesis), the same mechanisms could be complimentary to caffeine's established ability to suppress Aβ production. We conclude that coffee may be the best source of caffeine to protect against AD because of a component in coffee that synergizes with caffeine to enhance plasma GCSF levels, resulting in multiple therapeutic actions against AD.

  9. Caffeine increases the motivation to obtain non-drug reinforcers in rats

    PubMed Central

    Sheppard, A. Brianna; Gross, Skyler C.; Pavelka, Sarah A.; Hall, Melanie J.; Palmatier, Matthew I.

    2012-01-01

    BACKGROUND Caffeine is widely considered to be a reinforcer in humans, but this effect is difficult to measure in non-human animals. We hypothesized that caffeine may have dual reinforcing effects comparable to nicotine - limited primary reinforcing effects, but potent reinforcement enhancing effects. The present studies tested this hypothesis by investigating the effect of caffeine on responding for non-drug rewards. METHODS In two experiments, rats were shaped to respond on a progressive ratio (PR) schedule for sucrose solution (20% w/v; Experiment 1) or a fixed ratio 2 (FR2) schedule for a moderately reinforcing visual stimulus (VS; Experiment 2). Pretreatment with various doses of caffeine (0–50 mg/kg, intraperitoneal injection) were administered prior to tests over successive week days (M-F). In Experiment 1, acute administration of low-moderate caffeine doses (6.25–25 mg/kg) increased responding for sucrose under the PR schedule. This effect of caffeine declined over the initial 15 test days. In Experiment 2, only acute pretreatment with 12.5 mg/kg caffeine increased responding for the visual stimulus and complete tolerance to this effect of caffeine was observed over the 15 days of testing. In follow up tests we found that abstinence periods of 4 and 8 days resulted in incomplete recovery of the enhancing effects of caffeine. CONCLUSION The findings suggest that caffeine enhances the reinforcing effects of non-drug stimuli, but that the pharmacological profile of these effects may differ from other psychomotor stimulants. PMID:22336397

  10. Effect of different protocols of caffeine intake on metabolism and endurance performance.

    PubMed

    Cox, Gregory R; Desbrow, Ben; Montgomery, Paul G; Anderson, Megan E; Bruce, Clinton R; Macrides, Theodore A; Martin, David T; Moquin, Angela; Roberts, Alan; Hawley, John A; Burke, Louise M

    2002-09-01

    Competitive athletes completed two studies of 2-h steady-state (SS) cycling at 70% peak O(2) uptake followed by 7 kJ/kg time trial (TT) with carbohydrate (CHO) intake before (2 g/kg) and during (6% CHO drink) exercise. In Study A, 12 subjects received either 6 mg/kg caffeine 1 h preexercise (Precaf), 6 x 1 mg/kg caffeine every 20 min throughout SS (Durcaf), 2 x 5 ml/kg Coca-Cola between 100 and 120 min SS and during TT (Coke), or placebo. Improvements in TT were as follows: Precaf, 3.4% (0.2-6.5%, 95% confidence interval); Durcaf, 3.1% (-0.1-6.5%); and Coke, 3.1% (-0.2-6.2%). In Study B, eight subjects received 3 x 5 ml/kg of different cola drinks during the last 40 min of SS and TT: decaffeinated, 6% CHO (control); caffeinated, 6% CHO; decaffeinated, 11% CHO; and caffeinated, 11% CHO (Coke). Coke enhanced TT by 3.3% (0.8-5.9%), with all trials showing 2.2% TT enhancement (0.5-3.8%; P < 0.05) due to caffeine. Overall, 1) 6 mg/kg caffeine enhanced TT performance independent of timing of intake and 2) replacing sports drink with Coca-Cola during the latter stages of exercise was equally effective in enhancing endurance performance, primarily due to low intake of caffeine (approximately 1.5 mg/kg).

  11. On your marks, get set, go!-lessons from the UK in enhancing employability of graduates and postgraduates.

    PubMed

    Fahnert, Beatrix

    2015-10-01

    Employers expect graduates and postgraduates to demonstrate their education through more than good grades. Learning activities that develop subject skills during formalized programmes of undergraduate and postgraduate study also develop employability skills, if the curriculum is suitably aligned, and developmental planning is supported. Only little extra provision is required, but all development needs to be explicitly signposted to the learner, and the curriculum should be developed in consultation with employers. This review aims to raise awareness of current issues in the context of enhancing employability that arise from an increased global competition on the job market and the expectation of the Higher Education sector to produce work-ready graduates and postgraduates that are well equipped to adapt to a quickly changing work environment particularly due to transferable skills. In the context of lessons from the UK, these current issues and employability are discussed, and approaches to Personal Development Planning that prepare students for lifelong learning and that enable communicating and evidencing achievement are addressed. Issues specific to postgraduates, how actual work experience should be maximized as well as other career influences such as learned societies and social networking are highlighted. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. Nanoimmunoliposome Delivery of Superparamagnetic Iron Oxide Markedly Enhances Targeting and Uptake in Human Cancer Cells In Vitro and In Vivo

    PubMed Central

    Yang, Chengli; Rait, Antonina; Pirollo, Kathleen F.; Dagata, John A.; Farkas, Natalia; Chang, Esther H.

    2008-01-01

    To circumvent the problem of reduction of the supermagnetic properties of superparamagnetic iron oxide (SPIO) nanoparticles after chemical modification to conjugate targeting molecules, we have adapted a tumor-targeting nanoimmunoliposome platform technology (scL) to encapsulate and deliver SPIO (scL-SPIO) in vitro and in vivo without chemical modification. Scanning probe microscopy, confocal microscopy, and Prussian blue staining were employed to analyze the scL-SPIO nanoparticles and assess intracellular uptake and distribution of SPIO in vitro. In vivo targeting and tumor-specific uptake of scL-SPIO was examined using fluorescent-labeled SPIO. We demonstrated that SPIO encapsulation in the scL complex results in approximately an 11 fold increase in SPIO uptake in human cancer cells in vitro, with distribution to cytoplasm and nucleus. Moreover, the scL nanocomplex specifically and efficiently delivered SPIO into tumor cells after systemic administration, demonstrating the potential of this approach to enhance local tumor concentration and the utility of SPIO for clinical applications. PMID:18676207

  13. Maternal caffeine exposure impairs insulin secretion by pancreatic β-cells and increases the risk of type II diabetes mellitus in offspring.

    PubMed

    Sun, Tingting; Guo, Jinghui; Chen, Hui; Zhang, Jieting; Zhang, Xiaohu; Jiang, Xiaohua; Wang, Fuqiang; Xu, Zhiyang; Huang, Xiaoyan; Sha, Jiahao; Chan, Hsiao Chang

    2014-10-01

    Maternal caffeine exposure may be one of the causes for intrauterine growth retardation and low birth weight (LBW), and increased risk of type 2 diabetes mellitus (T2DM) in the adulthood has been associated with LBW. However, whether maternal caffeine exposure contributes to T2DM development of her offspring has not been fully investigated. We have investigated the influence of maternal caffeine exposure on glucose homeostasis in vivo and effects of long-term caffeine load on insulin secretion of β-cells. The intake of caffeine during gestation markedly decreases birth weight and postnatal body weight of the offspring. Serum insulin levels of adult offspring after oral glucose tolerance test (OGTT) were significantly lower in the caffeine group compared to the control, although plasma glucose levels were not significantly altered. Proteome analysis of pancreas of adult offspring identified 24 proteins that were differentially expressed between the caffeine and control groups, including proteins involved in energy metabolism. In a rat pancreatic β-cell line Rin-5f cells, caffeine downregulated expression of one of the proteins involved in insulin synthesis, P4hb, and there was reduced transcriptional expression of insulin. While basal insulin secretion of caffeine-treated cells was elevated, insulin secretion after glucose challenge in long-term caffeine-treated cells was significantly reduced, with increased apoptosis of β-cells. These results indicate that maternal caffeine exposure may result in potentially abnormal glucose homeostasis and increase the risk of T2DM in the offspring adulthood.

  14. Reduced effect of caffeine on twitch contraction of oesophageal striated muscle from stroke-prone spontaneously hypertensive rats.

    PubMed

    Sekiguchi, Fumiko; Kawata, Kyoko; Shimamura, Keiichi; Sunano, Satoru

    2003-04-01

    1. There are known differences in the sensitivity to caffeine between skeletal muscle (soleus) of normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). The present study was performed in order to examine differences in the effects of caffeine on twitch contraction between visceral striated muscle using the outer layer of the oesophagus from WKY rats and stroke-prone SHR (SHRSP). 2. Caffeine, at concentrations ranging from 0.3 to 10 mmol/L, exhibited potentiating effects on twitch contraction in preparations from both WKY rats and SHRSP. The potentiating effect of caffeine was markedly less prominent in preparations from SHRSP compared with preparations from WKY rats. 3. The rate of contraction and relaxation, the time to peak tension and 80% relaxation time were not significantly altered by caffeine at concentrations lower than 3 mmol/L in preparations from either strain. 4. With 10 mmol/L caffeine, the rate of relaxation was markedly reduced and the 80% relaxation time was prolonged, with no significant changes in the rate of contraction, in preparations from WKY rats. These changes were significantly smaller in preparations from SHRSP. 5. The duration of the action potential was greater in preparations from SHRSP than in preparations from WKY rats, although the membrane potential and the amplitude of the action potential were not significantly different between preparations from WKY rats and SHRSP. 6. Caffeine, at 10 mmol/L, prolonged the duration of the action potential in preparations from both strains. The effect of caffeine was not different between preparations from WKY rats and SHRSP. 7. The results of the present study suggest that caffeine augments release of Ca2+ from the sarcoplasmic reticulum (SR) at low concentrations and attenuates Ca2+ re-uptake at 10 mmol/L. Decreased reactivity of SR to caffeine may be a cause of the lesser potentiation of twitch contraction by caffeine in preparations from SHRSP.

  15. Coinciding exercise with peak serum caffeine does not improve cycling performance.

    PubMed

    Skinner, Tina L; Jenkins, David G; Taaffe, Dennis R; Leveritt, Michael D; Coombes, Jeff S

    2013-01-01

    To investigate whether coinciding peak serum caffeine concentration with the onset of exercise enhances subsequent endurance performance. Randomised, double-blind, crossover. In this randomised, placebo-controlled, double-blind crossover study, 14 male trained cyclists and triathletes (age 31±5year, body mass 75.4±5.7 kg, VO₂max 69.5±6.1 mL kg⁻¹ min⁻¹ and peak power output 417±35W, mean±SD) consumed 6 mg kg(-1) caffeine or a placebo either 1h (C(1h)) prior to completing a 40 km time trial or when the start of exercise coincided with individual peak serum caffeine concentrations (C(peak)). C(peak) was determined from a separate 'caffeine profiling' session that involved monitoring caffeine concentrations in the blood every 30 min over a 4h period. Following caffeine ingestion, peak serum caffeine occurred 120 min in 12 participants and 150 min in 2 participants. Time to complete the 40 km time trial was significantly faster (2.0%; p=0.002) in C(1h) compared to placebo. No statistically significant improvement in performance was noted in the C(peak) trial versus placebo (1.1%; p=0.240). Whilst no differences in metabolic markers were found between C(peak) and placebo conditions, plasma concentrations of glucose (p=0.005), norepinephrine and epinephrine (p≤0.002) were higher in the C(1h) trial 6 min post-exercise versus placebo. In contrast to coinciding peak serum caffeine concentration with exercise onset, caffeine consumed 60 min prior to exercise resulted in significant improvements in 40 km time trial performance. The ergogenic effect of caffeine was not found to be related to peak caffeine concentration in the blood at the onset of endurance exercise. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  16. Protective effect of low dose caffeine on psychological stress and cognitive function.

    PubMed

    Çakır, Özgür Kasımay; Ellek, Nurfitnat; Salehin, Nabila; Hamamcı, Rabia; Keleş, Hülya; Kayalı, Damla Gökçeoğlu; Akakın, Dilek; Yüksel, Meral; Özbeyli, Dilek

    2017-01-01

    Caffeine is an adrenergic antagonist that enhances neuronal activity. Psychological stress depresses cognitive function. To investigate the effects of acute and chronic low dose caffeine on anxiety-like behavior and cognitive functions of acute or chronic psychological stressed rats. Acute or chronic caffeine (3mg/kg) was administered to male Sprague Dawley rats (200-250g, n=42) before acute (cat odor) and chronic variable psychological stress (restraint overcrowding stress, elevated plus maze, cat odor, forced swimming) induction. Anxiety and cognitive functions were evaluated by hole-board and object recognition tests. The brain glutathione and malondialdehyde assays, myeloperoxidase, nitric oxide (NO), superoxide dismutase (SOD), luminol and lucigenin activity and histological examination were done. ANOVA and Student's t-test were used for statistical analysis. The depressed cognitive function with chronic stress exposure and the increased anxiety-like behavior with both stress inductions were improved via both caffeine applications (p<0.05-0.001). Both caffeine pretreatments in chronic stressed rats, and chronic caffeine in acute stressed ones reduced the elevated myeloperoxidase activities (p<0.05-0.01). The increased malondialdehyde, lucigenin and NO levels with acute stress were inhibited with chronic caffeine (p<0.05-0.01), malondialdehyde and NO levels were declined by acute caffeine (p<0.001). Acute caffeine decreased SOD activity (p<0.01) and improved glutathione (p<0.01) and luminol levels (p<0.05). The induced histological damage with both stress exposures was ameliorated with chronic caffeine. The increased anxiety-like behavior and depleted cognitive functions under stress conditions were improved with both acute and predominantly chronic caffeine pretreatments by decreasing oxidative damage parameters. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Branched oligomerization of cell-permeable peptides markedly enhances the transduction efficiency of adenovirus into mesenchymal stem cells.

    PubMed

    Park, S-H; Doh, J; Park, S I; Lim, J Y; Kim, S M; Youn, J-I; Jin, H-T; Seo, S-H; Song, M-Y; Sung, S Y; Kim, M; Hwang, S J; Choi, J-M; Lee, S-K; Lee, H Y; Lim, C L; Chung, Y J; Yang, D; Kim, H-N; Lee, Z H; Choi, K Y; Jeun, S-S; Sung, Y C

    2010-08-01

    Cell-permeable peptides (CPPs) promote the transduction of nonpermissive cells by recombinant adenovirus (rAd) to improve the therapeutic efficacy of rAd. In this study, branched oligomerization of CPPs significantly enhanced the transduction of human mesenchymal stem cells (MSCs) by rAd in a CPP type-independent manner. In particular, tetrameric CPPs increased transduction efficiency at 3000-5000-fold lower concentrations than did monomeric CPPs. Although branched oligomerization of CPPs also increases cytotoxicity, optimal concentrations of tetrameric CPPs required for maximum transduction are at least 300-1000-fold lower than those causing 50% cytotoxicity. Furthermore, although only approximately 60% of MSCs were maximally transduced at 500 muM of monomeric CPPs, >95% of MSCs were transduced with 0.1 muM of tetrameric CPPs. Tetrameric CPPs also significantly increased the formation and net surface charge of CPP/rAd complexes, as well as the binding of rAd to cell membranes at a greater degree than did monomeric CPPs, followed by rapid internalization into MSCs. In a critical-size calvarial defect model, the inclusion of tetrameric CPPs in ex vivo transduction of rAd expressing bone morphogenetic protein 2 into MSCs promoted highly mineralized bone formation. In addition, MSCs that were transduced with rAd expressing brain-derived neurotrophic factor in the presence of tetrameric CPPs improved functional recovery in a spinal cord injury model. These results demonstrated the potential for tetrameric CPPs to provide an innovative tool for MSC-based gene therapy and for in vitro gene delivery to MSCs.

  18. Marked enhancement of lysosomal targeting and efficacy of ErbB2-targeted drug delivery by HSP90 inhibition

    PubMed Central

    Mohapatra, Bhopal; Luan, Haitao; Soni, Kruti; Zhang, Jinjin; Storck, Matthew A.; Feng, Dan; Bielecki, Timothy A.; Band, Vimla; Cohen, Samuel M.; Bronich, Tatiana K.; Band, Hamid

    2016-01-01

    Targeted delivery of anticancer drugs to tumor cells using monoclonal antibodies against oncogenic cell surface receptors is an emerging therapeutic strategy. These strategies include drugs directly conjugated to monoclonal antibodies through chemical linkers (Antibody-Drug Conjugates, ADCs) or those encapsulated within nanoparticles that in turn are conjugated to targeting antibodies (Antibody-Nanoparticle Conjugates, ANPs). The recent FDA approval of the ADC Trastuzumab-TDM1 (Kadcyla®; Genentech; San Francisco) for the treatment of ErbB2-overexpressing metastatic breast cancer patients has validated the strong potential of these strategies. Even though the activity of ANPs and ADCs is dependent on lysosomal traffic, the roles of the endocytic route traversed by the targeted receptor and of cancer cell-specific alterations in receptor dynamics on the efficiency of drug delivery have not been considered in these new targeted therapies. For example, constitutive association with the molecular chaperone HSP90 is thought to either retard ErbB2 endocytosis or to promote its recycling, traits undesirable for targeted therapy with ANPs and ADCs. HSP90 inhibitors are known to promote ErbB2 ubiquitination, targeting to lysosome and degradation. We therefore hypothesized that ErbB2-targeted drug delivery using Trastuzumab-conjugated nanoparticles could be significantly improved by HSP90 inhibitor-promoted lysosomal traffic of ErbB2. Studies reported here validate this hypothesis and demonstrate, both in vitro and in vivo, that HSP90 inhibition facilitates the intracellular delivery of Trastuzumab-conjugated ANPs carrying a model chemotherapeutic agent, Doxorubicin, specifically into ErbB2-overexpressing breast cancer cells, resulting in improved antitumor activity. These novel findings highlight the need to consider oncogene-specific alterations in receptor traffic in the design of targeted drug delivery strategies. We suggest that combination of agents that enhance

  19. Marked enhancement of lysosomal targeting and efficacy of ErbB2-targeted drug delivery by HSP90 inhibition.

    PubMed

    Raja, Srikumar M; Desale, Swapnil S; Mohapatra, Bhopal; Luan, Haitao; Soni, Kruti; Zhang, Jinjin; Storck, Matthew A; Feng, Dan; Bielecki, Timothy A; Band, Vimla; Cohen, Samuel M; Bronich, Tatiana K; Band, Hamid

    2016-03-01

    Targeted delivery of anticancer drugs to tumor cells using monoclonal antibodies against oncogenic cell surface receptors is an emerging therapeutic strategy. These strategies include drugs directly conjugated to monoclonal antibodies through chemical linkers (Antibody-Drug Conjugates, ADCs) or those encapsulated within nanoparticles that in turn are conjugated to targeting antibodies (Antibody-Nanoparticle Conjugates, ANPs). The recent FDA approval of the ADC Trastuzumab-TDM1 (Kadcyla; Genentech; San Francisco) for the treatment of ErbB2-overexpressing metastatic breast cancer patients has validated the strong potential of these strategies. Even though the activity of ANPs and ADCs is dependent on lysosomal traffic, the roles of the endocytic route traversed by the targeted receptor and of cancer cell-specific alterations in receptor dynamics on the efficiency of drug delivery have not been considered in these new targeted therapies. For example, constitutive association with the molecular chaperone HSP90 is thought to either retard ErbB2 endocytosis or to promote its recycling, traits undesirable for targeted therapy with ANPs and ADCs. HSP90 inhibitors are known to promote ErbB2 ubiquitination, targeting to lysosome and degradation. We therefore hypothesized that ErbB2-targeted drug delivery using Trastuzumab-conjugated nanoparticles could be significantly improved by HSP90 inhibitor-promoted lysosomal traffic of ErbB2. Studies reported here validate this hypothesis and demonstrate, both in vitro and in vivo, that HSP90 inhibition facilitates the intracellular delivery of Trastuzumab-conjugated ANPs carrying a model chemotherapeutic agent, Doxorubicin, specifically into ErbB2-overexpressing breast cancer cells, resulting in improved antitumor activity. These novel findings highlight the need to consider oncogene-specific alterations in receptor traffic in the design of targeted drug delivery strategies. We suggest that combination of agents that enhance receptor

  20. Nicotine Deprivation Produces Deficits in Pain Perception that are Moderately Attenuated by Caffeine Consumption.

    PubMed

    Baiamonte, Brandon A; Stickley, Sarah C; Ford, Sarah J

    2016-01-01

    During withdrawal, nicotine users experience aversive withdrawal symptoms, such as increased nociceptive processing, which may be responsible for subsequent use. Smokers often consume more caffeine than non-smokers and the combined effects of these two psychoactive drugs result in an enhanced analgesic effect of nicotine. We examined the effects of caffeine (via coffee consumption) and nicotine withdrawal on pain perception in minimally deprived smokers and non-smokers. Pain threshold and pain tolerance were assessed using a radiant heat stimulus before and 30 minutes after caffeine consumption. Nicotine deprivation (2 hrs) produced increases in pain threshold and decreases in pain tolerance representative of hyperalgesia. When smokers are nicotine deprived, caffeine consumption diminished baseline elevations in pain threshold, but had no effect on pain tolerance. These data suggest that caffeine consumption can dampen deficits in sensory discrimination related to pain during nicotine deprivation by reducing pain threshold to levels representative of non-smoking controls.

  1. Caffeine Induces a Stimulant Effect and Increases Dopamine Release in the Nucleus Accumbens Shell Through the Pulmonary Inhalation Route of Administration in Rats.

    PubMed

    Galvalisi, Martín; Prieto, José Pedro; Martínez, Marcela; Abin-Carriquiry, Juan Andrés; Scorza, Cecilia

    2017-01-01

    Oral, intraperitoneal, or intravenous have been the common routes of administration used to study the behavioral and neurochemical pharmacology of caffeine, one of the most widely used psychoactive substances worldwide. We have reported that caffeine is an active adulterant frequently found in coca-paste (CP)-seized samples, a highly addictive form of smokable cocaine. The role of caffeine in the psychostimulant and neurochemical effects induced by CP remains under study. No preclinical animal studies have been performed so far to characterize the effects of caffeine when it is administered through the pulmonary inhalation route. Caffeine (10, 25, and 50 mg) was volatilized and rats were exposed to one inhalation session of its vapor. The stimulant effect was automatically recorded and plasmatic levels of caffeine were measured. Caffeine capability (50 mg) to increase extracellular dopamine (DA) levels in nucleus accumbens shell was also studied by in vivo microdialysis in non-anesthetized animals. A dose-dependent stimulant effect induced by volatilized caffeine was observed and this effect was directly related with caffeine plasmatic levels. A significant increase in the extracellular DA was achieved after 50 mg of volatilized caffeine exposure. This is the first report showing pharmacological acute effects of caffeine through the pulmonary inhalation route of administration and suggests that this could be a condition under which caffeine can elevate its weak reinforcing effect and even enhance the psychostimulant effect and abuse liability of smokable adulterated psychostimulant drugs.

  2. Mechanism by which caffeine potentiates lethality of nitrogen mustard.

    PubMed Central

    Lau, C C; Pardee, A B

    1982-01-01

    Caffeine is synergistic with many DNA-damaging agents in increasing lethality to mammalian cells. The mechanism is not well understood. Our results show that caffeine potentiates the lethality of the nitrogen mustard 2-chloro-N-(2-chloroethyl)-N-methylethanamine (HN2) by inducing damaged cells to undergo mitosis before properly repairing lesions in their DNA. Treatment with low doses of HN2 (0.5 microM for 1 hr) caused little lethality in baby hamster kidney cells (90% survival). These cells were arrested in G2 shortly after treatment with HN2 as shown by flow microfluorimetry and autoradiography. After an arrest of 6 hr, HN2-treated cells began to move into mitosis and from then on behaved like normal cells. Repair synthesis was shown to continue during the G2 arrest by using synchronized cells pulse labeled with [3H]thymidine after HN2 treatment and autoradiography. Caffeine (2mM) increased the lethality of HN2 by 5- to 10-fold. It prevented the G2 arrest. Caffeine did not prevent these HN2-treated cells from entering or completing S phase but rather allowed them to divide without finishing the repair processes and as a consequence caused nuclear fragmentation after mitosis. Caffeine-induced nuclear fragmentation and enhanced lethality were proportional, as shown with dose--response curves and time dependence. In addition, both lethality and nuclear fragmentation were abolished by low doses of cycloheximide, an inhibitor of protein synthesis. Images PMID:6953438

  3. Combined caffeine and carbohydrate ingestion: effects on nocturnal sleep and exercise performance in athletes.

    PubMed

    Miller, Ben; O'Connor, Helen; Orr, Rhonda; Ruell, Patricia; Cheng, Hoi Lun; Chow, Chin Moi

    2014-12-01

    In athletes, caffeine use is common although its effects on sleep have not been widely studied. This randomised, double-blind, placebo-controlled crossover trial investigated the effects of late-afternoon caffeine and carbohydrate-electrolyte (CEB) co-ingestion on cycling performance and nocturnal sleep. Six male cyclists/triathletes (age 27.5 ± 6.9 years) completed an afternoon training session (TS; cycling 80 min; 65% VO₂max) followed by a 5 kJ kg(-1) cycling time trial (TT). Caffeine (split dose 2 × 3 mg kg(-1)) or placebo was administered 1 h prior and 40 min into the TS. A 7.4% CEB (3 ml kg(-1) every 15 min) was administered during the TS, followed 30 min after by a standardised evening meal. Participants retired at their usual bedtime and indices of sleep duration and quality were monitored via polysomnography. mean ± SD. All participants performed better in the caffeine TT (caffeine 19.7 ± 3.3; placebo 20.5 ± 3.5 min; p = 0.006), while ratings of perceived exertion (caffeine 12.0 ± 0.6; placebo 12.9 ± 0.7; p = 0.004) and heart rate (caffeine 175 ± 6; placebo 167 ± 11 bpm; p = 0.085) were lower in the caffeine TS. Caffeine intake induced significant disruptions to a number of sleep indices including increased sleep onset latency (caffeine 51.1 ± 34.7; placebo 10.2 ± 4.2 min; p = 0.028) and decreased sleep efficiency (caffeine 76.1 ± 19.6; placebo 91.5 ± 4.2%; p = 0.028), rapid eye movement sleep (caffeine 62.1 ± 19.6; placebo 85.8 ± 24.7 min; p = 0.028) and total sleep time (caffeine 391 ± 97; placebo 464 ± 49 min; p = 0.028). This study supports a performance-enhancing effect of caffeine, although athletes (especially those using caffeine for late-afternoon/evening training and competition) should consider its deleterious effects on sleep.

  4. Caffeine's Vascular Mechanisms of Action

    PubMed Central

    Echeverri, Darío; Montes, Félix R.; Cabrera, Mariana; Galán, Angélica; Prieto, Angélica

    2010-01-01

    Caffeine is the most widely consumed stimulating substance in the world. It is found in coffee, tea, soft drinks, chocolate, and many medications. Caffeine is a xanthine with various effects and mechanisms of action in vascular tissue. In endothelial cells, it increases intracellular calcium stimulating the production of nitric oxide through the expression of the endothelial nitric oxide synthase enzyme. Nitric oxide is diffused to the vascular smooth muscle cell to produce vasodilation. In vascular smooth muscle cells its effect is predominantly a competitive inhibition of phosphodiesterase, producing an accumulation of cAMP and vasodilation. In addition, it blocks the adenosine receptors present in the vascular tissue to produce vasoconstriction. In this paper the main mechanisms of action of caffeine on the vascular tissue are described, in which it is shown that caffeine has some cardiovascular properties and effects which could be considered beneficial. PMID:21188209

  5. Caffeine effect in vestibular system.

    PubMed

    Ledesma, Alleluia Lima Losno; Barreto, Monique Antunes de Souza Chelminski; Bahmad, Fayez

    2014-01-01

    Caffeine benefits and harms in health is a very controversial subject for a scientific research. This is a systematic literature using PubMed database linking caffeine with the following keywords: 'vestibular', 'vertigo', 'vestibular function', 'caloric tests' e 'electronystagmography". Thirty articles were found and ten were analyzed for fulfill the inclusion criteria. These ten articles were grouped and then a separated in four groups, according to the approach. There is a need of further randomized and controlled studies to understand the vestibular system.

  6. Caffeine Positively Modulates Ferritin Heavy Chain Expression in H460 Cells: Effects on Cell Proliferation

    PubMed Central

    Battaglia, Anna Martina; Faniello, Maria Concetta; Cuda, Giovanni; Costanzo, Francesco

    2016-01-01

    Both the methylxanthine caffeine and the heavy subunit of ferritin molecule (FHC) are able to control the proliferation rate of several cancer cell lines. While caffeine acts exclusively as a negative modulator of cell proliferation, FHC might reduce or enhance cell viability depending upon the different cell type. In this work we have demonstrated that physiological concentrations of caffeine reduce the proliferation rate of H460 cells: along with the modulation of p53, pAKT and Cyclin D1, caffeine also determines a significant FHC up-regulation through the activation of its transcriptional efficiency. FHC plays a central role in the molecular pathways modulated by caffeine, ending in a reduced cell growth, since its specific silencing by siRNA almost completely abolishes caffeine effects on H460 cell proliferation. These results allow the inclusion of ferritin heavy subunits among the multiple molecular targets of caffeine and open the way for studying the relationship between caffeine and intracellular iron metabolism. PMID:27657916

  7. Effects of dilute aqueous NaCl solution on caffeine aggregation

    NASA Astrophysics Data System (ADS)

    Sharma, Bhanita; Paul, Sandip

    2013-11-01

    The effect of salt concentration on association properties of caffeine molecule was investigated by employing molecular dynamics simulations in isothermal-isobaric ensemble of eight caffeine molecules in pure water and three different salt (NaCl) concentrations, at 300 K temperature and 1 atm pressure. The concentration of caffeine was taken almost at the solubility limit. With increasing salt concentration, we observe enhancement of first peak height and appearance of a second peak in the caffeine-caffeine distribution function. Furthermore, our calculated solvent accessible area values and cluster structure analyses suggest formation of higher order caffeine cluster on addition of salt. The calculated hydrogen bond properties reveal that there is a modest decrease in the average number of water-caffeine hydrogen bonds on addition of NaCl salt. Also observed are: (i) decrease in probability of salt contact ion pair as well as decrease in the solvent separated ion pair formation with increasing salt concentration, (ii) a modest second shell collapse in the water structure, and (iii) dehydration of hydrophobic atomic sites of caffeine on addition of NaCl.

  8. Unexpectedly strong effect of caffeine on the vitality of western honeybees (Apis mellifera).

    PubMed

    Strachecka, A; Krauze, M; Olszewski, K; Borsuk, G; Paleolog, J; Merska, M; Chobotow, J; Bajda, M; Grzywnowicz, K

    2014-11-01

    We examined the influence of caffeine on honeybee lifespan, Nosema resistance, key enzyme activities, metabolic compound concentrations, and total DNA methylation levels. Caffeine slowed age-related metabolic tendencies. Bees that consumed caffeine lived longer and were not infested with Nosema spp. Caffeine-treated workers had higher protein concentrations. The levels increased with aging but they then decreased in older bees. Caffeine increased the activities of antioxidant enzymes (SOD, GPx, CAT, GST), AST, ALT, ALP, neutral proteases, and protease inhibitors, and the concentrations of uric acid, triglycerides, cholesterol, glucose, and Ca2+. Acidic and alkaline protease activities were lower in the bees treated with caffeine. Creatinine and Mg2+ concentrations were higher in the caffeine-treated workers but only up to 14 days of age. Caffeine significantly decreased DNA methylation levels in older bees. The compound could be considered as a natural diet supplement increasing apian resistance to stress factors. Our studies will enhance possibilities of using Apis mellifera as a model organism in gerontological studies.

  9. Effects of dilute aqueous NaCl solution on caffeine aggregation

    SciTech Connect

    Sharma, Bhanita; Paul, Sandip

    2013-11-21

    The effect of salt concentration on association properties of caffeine molecule was investigated by employing molecular dynamics simulations in isothermal-isobaric ensemble of eight caffeine molecules in pure water and three different salt (NaCl) concentrations, at 300 K temperature and 1 atm pressure. The concentration of caffeine was taken almost at the solubility limit. With increasing salt concentration, we observe enhancement of first peak height and appearance of a second peak in the caffeine-caffeine distribution function. Furthermore, our calculated solvent accessible area values and cluster structure analyses suggest formation of higher order caffeine cluster on addition of salt. The calculated hydrogen bond properties reveal that there is a modest decrease in the average number of water-caffeine hydrogen bonds on addition of NaCl salt. Also observed are: (i) decrease in probability of salt contact ion pair as well as decrease in the solvent separated ion pair formation with increasing salt concentration, (ii) a modest second shell collapse in the water structure, and (iii) dehydration of hydrophobic atomic sites of caffeine on addition of NaCl.

  10. Effects of Cola-Flavored Beverages and Caffeine on Streptococcus mutans Biofilm Formation and Metabolic Activity.

    PubMed

    Dotsey, Roger P; Moser, Elizabeth A S; Eckert, George J; Gregory, Richard L

    To examine the effects of cola-flavored beverages and caffeine on growth and metabolism of Streptococcus mutans biofilm. This study was designed to determine if carbonated beverages or caffeine can increase S. mutans growth and biofilm formation and metabolic activity in vitro, potentially leading to increased S. mutans-associated cariogenicity in children that consume them. Six different cola-flavored products, plus pure caffeine, and pure high fructose corn syrup (HFCS), at different concentrations similar to those in the beverages were tested. A 16-hour culture of S. mutans was treated with different dilutions in bacteriological media. To test for the effect on biofilm formation, the biofilm was stained with crystal violet. The absorbance was determined to evaluate biofilm growth. Biofilm metabolic activity was measured based on biofilm having the ability to reduce XTT to a water-soluble orange compound. The inclusion of HFCS in the beverages, as well as pure HFCS, significantly enhanced bacterial biofilm formation and metabolic activity. Pure caffeine and the presence of caffeine in beverages did not significantly increase biofilm formation, but pure caffeine significantly increased metabolism, and Diet Coke had significantly greater metabolic activity than Caffeine-Free Diet Coke. HFCS increases both the biofilm formation and metabolism of S. mutans, and caffeine in some cases increases metabolism of S. mutans.

  11. Effect of caffeine on the neuromuscular system--potential as an ergogenic aid.

    PubMed

    Tarnopolsky, Mark A

    2008-12-01

    The ergogenic effect of caffeine on endurance exercise performance is multifactorial; however, there is evidence for an effect on both the central nervous system and the excitation-contraction coupling of skeletal muscle. The increase in exercise performance seen following intracerebroventrical caffeine injection in rats provides strong evidence for a central ergogenic effect. The central ergogenic effect is not likely related to the ability of caffeine to promote wakefulness, but could be due to an increase in the pain and effort perception threshold. There is no evidence that caffeine alters peripheral nerve conduction velocity or neuromuscular transmission, and 1 study showed that motor unit synchronization was not altered by caffeine. Studies have also shown that caffeine can have a direct effect on skeletal muscle that could be ergogenic. For example, patients with high cervical spinal cord lesions showed improvements in stimulated contractile force during cycling, in spite of the fact that they have no peripheral pain input and no sympathetic nervous system response. Two studies have found a potentiation of force production during submaximal stimulation intensities, and 1 found that the M-wave amplitude was not altered by caffeine. Together, these studies suggest that caffeine can enhance contractile force during submaximal contractions by potentiating calcium release from the ryanodine receptor, not by altering sarcoplasmic excitability. Furthermore, the potentiation of force during submaximal electrical stimulation is identical in habitual and nonhabitual caffeine consumers. In summary, the ergogenic effects of caffeine during endurance activity are mediated partly by enhanced contractile force and partly by a reduction in perceived exertion, possibly though a blunting of effort and (or) pain.

  12. Modulation of caffeine contractures in mammalian skeletal muscles by variation of extracellular potassium.

    PubMed

    Gallant, E M; Lentz, L R; Taylor, S R

    1995-11-01

    Caffeine contractures were induced after K(+)-conditioning of skeletal muscles from pigs and mice. K(+)-conditioning is defined as the partial depolarization caused by increasing external potassium (K+0) with [K+]x[Cl-] constant. Conditioning depolarizations that rendered muscles refractory to brief electrical stimulation still enhanced the contracture tension elicited by subsequent direct caffeine stimulation of sarcoplasmic reticulum (SR) calcium release. The effects of K(+)-conditioning on caffeine-induced contractures of intact cell bundles reached a maximum at 15-30 mM K+0 and then progressively declined at higher [K+]0. Conditioning with 30 mM K+ for 5 min, which inactivates excitation-contraction (EC) coupling in response to action potentials, both increased the magnitude of caffeine contractures 2-10-fold and shifted the contracture threshold toward lower caffeine concentrations. Enhanced sensitivity to caffeine was inhibited by dantrolene (20 microM) and its watersoluble analogue azumolene (150 microM). These drugs decreased caffeine-induced contractures following depolarization with 4-15 mM K+ to 25-50% of control tension. The inorganic anion perchlorate (CIO-4), which like caffeine potentiates twitches, increased caffeine-induced contractures approximately twofold after K(+)-conditioning (> 4 mM). The results suggest that CIO-4 and dantrolene, in addition to caffeine, also influence SR calcium release either directly or by mechanism(s) subsequent to depolarization of the sarcolemma. Moreover, since CIO-4 is known to shift the voltage-dependence of intramembrane charge movement, CIO-4 may exert effects on the transverse-tubule voltage sensors as well as the SR.

  13. Discriminative Stimulus Effects of Binary Drug Mixtures: Studies with Cocaine, MDPV, and Caffeine

    PubMed Central

    Abbott, Megan; Galindo, Kayla; Rush, Elise L.; Rice, Kenner C.; France, Charles P.

    2016-01-01

    Illicit drug preparations often include more than one pharmacologically active compound. For example, cocaine and synthetic cathinones [e.g., 3,4-methylenedioxypyrovalerone (MDPV)] are often mixed with caffeine before sale. Caffeine is likely added to these preparations because it is inexpensive and legal; however, caffeine might also mimic or enhance some of the effects of cocaine or MDPV. In these studies, male Sprague-Dawley rats were trained to discriminate 10 mg/kg cocaine from saline, and the discriminative stimulus effects of cocaine, caffeine, and MDPV were evaluated alone and as binary mixtures (cocaine and caffeine, MDPV and caffeine, and cocaine and MDPV) at fixed-dose ratios of 3:1, 1:1, and 1:3 relative to the dose of each drug that produced 50% cocaine-appropriate responding. Dose-addition analyses were used to determine the nature of the drug-drug interactions for each mixture (e.g., additive, supra-additive, or subadditive). Although additive interactions were observed for most mixtures, supra-additive interactions were observed at the 50% effect level for the 1:1 mixture of cocaine and caffeine and at the 80% effect level for all three mixtures of cocaine and caffeine, as well as for the 3:1 and 1:3 mixtures of cocaine and MDPV. These results demonstrate that with respect to cocaine-like discriminative stimulus effects, caffeine can function as a substitute in drug preparations containing either cocaine or MDPV, with enhancements of cocaine-like effects possible under certain conditions. Further research is needed to determine whether similar interactions exist for other abuse-related or toxic effects of drug preparations, including cocaine, synthetic cathinones, and caffeine. PMID:27493274

  14. Discriminative Stimulus Effects of Binary Drug Mixtures: Studies with Cocaine, MDPV, and Caffeine.

    PubMed

    Collins, Gregory T; Abbott, Megan; Galindo, Kayla; Rush, Elise L; Rice, Kenner C; France, Charles P

    2016-10-01

    Illicit drug preparations often include more than one pharmacologically active compound. For example, cocaine and synthetic cathinones [e.g., 3,4-methylenedioxypyrovalerone (MDPV)] are often mixed with caffeine before sale. Caffeine is likely added to these preparations because it is inexpensive and legal; however, caffeine might also mimic or enhance some of the effects of cocaine or MDPV. In these studies, male Sprague-Dawley rats were trained to discriminate 10 mg/kg cocaine from saline, and the discriminative stimulus effects of cocaine, caffeine, and MDPV were evaluated alone and as binary mixtures (cocaine and caffeine, MDPV and caffeine, and cocaine and MDPV) at fixed-dose ratios of 3:1, 1:1, and 1:3 relative to the dose of each drug that produced 50% cocaine-appropriate responding. Dose-addition analyses were used to determine the nature of the drug-drug interactions for each mixture (e.g., additive, supra-additive, or subadditive). Although additive interactions were observed for most mixtures, supra-additive interactions were observed at the 50% effect level for the 1:1 mixture of cocaine and caffeine and at the 80% effect level for all three mixtures of cocaine and caffeine, as well as for the 3:1 and 1:3 mixtures of cocaine and MDPV. These results demonstrate that with respect to cocaine-like discriminative stimulus effects, caffeine can function as a substitute in drug preparations containing either cocaine or MDPV, with enhancements of cocaine-like effects possible under certain conditions. Further research is needed to determine whether similar interactions exist for other abuse-related or toxic effects of drug preparations, including cocaine, synthetic cathinones, and caffeine. U.S. Government work not protected by U.S. copyright.

  15. Ciprofloxacin-caffeine: a drug interaction established using in vivo and in vitro investigations.

    PubMed

    Harder, S; Fuhr, U; Staib, A H; Wolff, T

    1989-11-30

    The inhibitory effects of ciprofloxacin and other quinolone derivatives on the hepatic cytochrome P450-dependent metabolism of caffeine have been investigated in humans. In vivo studies involved an intraindividual comparison of the single-dose kinetics of caffeine before and during quinolone administration in 12 healthy men. Changes of enzymatic caffeine degradation by the quinolones were studied in vitro using human liver microsomes from three donors. Enoxacin and pipemidic acid markedly prolonged caffeine elimination in vivo. A positive correlation exists between the doses of enoxacin or ciprofloxacin and the prolongation (increases) in the caffeine elimination half-life. Decreases in caffeine elimination, using doses of ciprofloxacin in the upper part of the recommended dose range, were approximately 1.5-fold in comparison with untreated control subjects, whereas in the case of enoxacin there was a sixfold change. In vitro results with enoxacin, ofloxacin, ciprofloxacin, and pipemidic acid show a competitive inhibition (Dixon plots) of caffeine 3-demethylation. Ciprofloxacin and enoxacin showed the strongest inhibitory effects in vitro, whereas ofloxacin had the lowest inhibitory effect. These results are qualitatively reflected in the in vivo results; however, the clinical effects may be dependent on pharmacokinetic disposition of the quinolone and this could explain the weak inhibitory action of ciprofloxacin in vivo.

  16. The in vitro effects of caffeine on viability, cycle cycle profiles, proliferation, and apoptosis of glioblastomas.

    PubMed

    Jiang, J; Lan, Y-Q; Zhang, T; Yu, M; Liu, X-Y; Li, L-H; Chen, X-P

    2015-09-01

    We studied the effects of caffeine on cell viability, cell cycle profiles, proliferation, and apoptosis in rat C6 and human U87MG glioblastoma cell lines. Cell viability was quantified by the methyl thiazolyl tetrazolium (MTT) assay. Flow cytometry was used to quantify the relative number of cells in different phases of the cell cycle, while cell proliferation was quantified using the Cell Counting Kit-8. The proportion of apoptotic cells was determined by flow cytometry, and expression of apoptosis-related proteins Caspase-3, Cyt-C, Bax and Bcl-2 by Western blot. Caffeine at doses of up to 0.5 mM did not affect cell viability in both rat C6 and human U87MG glioblastoma cells. Further studies were done using the dose of 0.5 mM. Percentage of cells in the G0/G1 phase was markedly increased, while percentage of cells in the S phase decreased, after cell treatment with caffeine. Cell proliferation was significantly inhibited by caffeine. Furthermore, caffeine induced cell apoptosis, decreased expression of Bcl-2, and increased expression of Cyt-C and Caspase-3. Caffeine inhibits proliferation and induces apoptosis in glioblastoma cells. Our results provide the experimental basis for further studies of potential role of caffeine in the treatment of glioblastomas.

  17. Caffeine and caffeinated beverage consumption and risk of spontaneous abortion.

    PubMed

    Hahn, K A; Wise, L A; Rothman, K J; Mikkelsen, E M; Brogly, S B; Sørensen, H T; Riis, A H; Hatch, E E

    2015-05-01

    Is caffeine and caffeinated beverage consumption associated with the risk of spontaneous abortion (SAB)? While preconceptional caffeine consumption was not materially associated with an increased risk of SAB, consumption during early pregnancy was associated with a small increased risk of SAB, although the relation was not linear. Caffeine has been hypothesized as a risk factor for SAB since the 1980s; however, results from previous studies have been conflicting. This prospective cohort study included 5132 Danish women planning pregnancy and enrolled from 2007 to 2010. Participants were women who conceived after entry into the Snart-Gravid cohort and who were aged 18-40, in a stable relationship with a male partner, and did not use fertility treatments to conceive. Women reported their daily caffeine and caffeinated beverage consumption on questionnaires before conception and during early pregnancy. All exposure measurements were prospective with respect to outcome ascertainment. We estimated hazard ratios (HRs) of SAB for categories of caffeine consumption in milligrams (mg) per day and the corresponding 95% confidence intervals (CIs) using Cox proportional hazards regression models with gestational weeks as the time scale. There were 732 women (14.3%) who were identified as having a SAB. In the preconceptional period, caffeine consumption was not materially associated with SAB risk (HR comparing ≥300 with <100 mg/day: 1.09; 95% CI: 0.89, 1.33). In early pregnancy, the HRs for 100-199, 200-299 and ≥300 mg/day of caffeine consumption were 1.62 (95% CI: 1.19, 2.22), 1.48 (95% CI: 1.03, 2.13) and 1.23 (95% CI: 0.61, 2.46), respectively, compared with that for <100 mg/day. The observed results may be affected by non-differential exposure misclassification, reverse causation and residual confounding. This is the largest study to date of prospectively measured, preconception caffeine consumption and risk of SAB. We were able to reduce the likelihood of differential

  18. Caffeine and caffeinated beverage consumption and risk of spontaneous abortion

    PubMed Central

    Hahn, K.A.; Wise, L.A.; Rothman, K.J.; Mikkelsen, E.M.; Brogly, S.B.; Sørensen, H.T.; Riis, A.H.; Hatch, E.E.

    2015-01-01

    STUDY QUESTION Is caffeine and caffeinated beverage consumption associated with the risk of spontaneous abortion (SAB)? SUMMARY ANSWER While preconceptional caffeine consumption was not materially associated with an increased risk of SAB, consumption during early pregnancy was associated with a small increased risk of SAB, although the relation was not linear. WHAT IS KNOWN ALREADY Caffeine has been hypothesized as a risk factor for SAB since the 1980s; however, results from previous studies have been conflicting. STUDY DESIGN, SIZE, DURATION This prospective cohort study included 5132 Danish women planning pregnancy and enrolled from 2007 to 2010. PARTICIPANTS/MATERIALS, SETTING, METHODS Participants were women who conceived after entry into the Snart-Gravid cohort and who were aged 18–40, in a stable relationship with a male partner, and did not use fertility treatments to conceive. Women reported their daily caffeine and caffeinated beverage consumption on questionnaires before conception and during early pregnancy. All exposure measurements were prospective with respect to outcome ascertainment. We estimated hazard ratios (HRs) of SAB for categories of caffeine consumption in milligrams (mg) per day and the corresponding 95% confidence intervals (CIs) using Cox proportional hazards regression models with gestational weeks as the time scale. MAIN RESULTS AND THE ROLE OF CHANCE There were 732 women (14.3%) who were identified as having a SAB. In the preconceptional period, caffeine consumption was not materially associated with SAB risk (HR comparing ≥300 with <100 mg/day: 1.09; 95% CI: 0.89, 1.33). In early pregnancy, the HRs for 100–199, 200–299 and ≥300 mg/day of caffeine consumption were 1.62 (95% CI: 1.19, 2.22), 1.48 (95% CI: 1.03, 2.13) and 1.23 (95% CI: 0.61, 2.46), respectively, compared with that for <100 mg/day. LIMITATIONS, REASONS FOR CAUTION The observed results may be affected by non-differential exposure misclassification, reverse

  19. Effects of caffeine, caffeine-associated stimuli, and caffeine-related information on physiological and psychological arousal.

    PubMed

    Mikalsen, A; Bertelsen, B; Flaten, M A

    2001-10-01

    To test the classical conditioning and expectancy theories of placebo effects. Two experiments investigated whether administration of caffeine-associated stimuli elicited conditioned arousal, and whether information that a drink contained or did not contain caffeine modulated arousal. Experiment 1 (n=21) used a 2 Caffeine (0 and 2 mg/kg) x 2 Solution (Coffee, Juice) x 2 Information (Told caffeine, Told not-caffeine) within-subjects design. Experiment 2 (n=48) used a 2 Solution (Coffee, Orange juice) x 3 Information (Told caffeine, Told not-caffeine, No information) between-subjects design. Indexes of arousal were skin conductance responses and levels, startle eyeblink reflexes, cardiovascular measures, and the Bond and Lader 1974 mood scale. Caffeine-associated stimuli increased alertness, contentedness and skin conductance levels, and information that the drink contained caffeine decreased calmness in Experiment 1. However, unexpected information about the caffeine content of the drink, and the order of the conditions, could have masked some effects of the experimental manipulations. Experiment 2 followed up this hypothesis. The results showed a conditioned increase in startle eyeblink reflexes, and that caffeine-associated stimuli together with information that the drink contained caffeine increased contentedness. Caffeine-associated stimuli increased arousal, and information about the content of the drink modulated arousal in the direction indicated by the information. Thus, both the classical conditioning and expectancy theories of placebo effects received support, and placebo effects were strongest when both conditioned responses and expectancy-based responses acted in the same direction.

  20. The effect of caffeine on skeletal muscle anabolic signaling and hypertrophy.

    PubMed

    Moore, Timothy M; Mortensen, Xavier M; Ashby, Conrad K; Harris, Alexander M; Kump, Karson J; Laird, David W; Adams, Aaron J; Bray, Jeremy K; Chen, Ting; Thomson, David M

    2017-06-01

    Caffeine is a widely consumed stimulant with the potential to enhance physical performance through multiple mechanisms. However, recent in vitro findings have suggested that caffeine may block skeletal muscle anabolic signaling through AMP-activated protein kinase (AMPK)-mediated inhibition of mechanistic target of rapamycin (mTOR) signaling pathway. This could negatively affect protein synthesis and the capacity for muscle growth. The primary purpose of this study was to assess the effect of caffeine on in vivo AMPK and mTOR pathway signaling, protein synthesis, and muscle growth. In cultured C2C12 muscle cells, physiological levels of caffeine failed to impact mTOR activation or myoblast proliferation or differentiation. We found that caffeine administration to mice did not significantly enhance the phosphorylation of AMPK or inhibit signaling proteins downstream of mTOR (p70S6k, S6, or 4EBP1) or protein synthesis after a bout of electrically stimulated contractions. Skeletal muscle-specific knockout of LKB1, the primary AMPK activator in skeletal muscle, on the other hand, eliminated AMPK activation by contractions and enhanced S6k, S6, and 4EBP1 activation before and after contractions. In rats, the addition of caffeine did not affect plantaris hypertrophy induced by the tenotomy of the gastrocnemius and soleus muscles. In conclusion, caffeine administration does not impair skeletal muscle load-induced mTOR signaling, protein synthesis, or muscle hypertrophy.

  1. The effect of caffeine ingestion on functional performance in older adults.

    PubMed

    Duncan, M J; Clarke, N D; Tallis, J; Guimarães-Ferreira, L; Leddington Wright, S

    2014-12-01

    Caffeine is a widely used nutritional supplement which has been shown to enhance both physical and cognitive performance in younger adults. However, few studies have assessed the effect of caffeine ingestion on performance, particularly functional performance in older adults. The present study aims to assess the effect of acute caffeine ingestion on functional performance, manual dexterity and readiness to invest effort in older adults. 19 apparently healthy, volunteers (10 females and 9 males aged 61-79; 66 ± 2 years) performed tests of functional fitness and manual dexterity post ingestion of caffeine (3mg*kg-1) or placebo in a randomised order. Pre and 60 minutes post ingestion, participants also completed measures of readiness to invest physical (RTIPE) and mental (RTIME) effort. A series of repeated measures ANOVAS indicated enhanced performance in the following functional fitness tests; arm curls (P = .04), 8 foot up and go (P = .007), six minute walk (P = .016). Manual dexterity was also improved in the presence of caffeine (P = .001). RTIME increased (P = .015) pre to post ingestion in the caffeine condition but not in the placebo condition. There were no significant main effects or interactions for RTIPE or gender in any analysis (all P > .05). The results of this study suggest that acute caffeine ingestion positively enhances functional performance, manual dexterity and readiness to invest effort in apparently healthy older adults.

  2. Effects of caffeine on sleep and cognition.

    PubMed

    Snel, Jan; Lorist, Monicque M

    2011-01-01

    Caffeine can be used effectively to manipulate our mental state. It is beneficial in restoring low levels of wakefulness and in counteracting degraded cognitive task performance due to sleep deprivation. However, caffeine may produce detrimental effects on subsequent sleep, resulting in daytime sleepiness. This justifies a careful consideration of risks related to sleep deprivation in combination with caffeine consumption, especially in adolescents. The efficacy of caffeine to restore detrimental effects of sleep deprivation seems to be partly due to caffeine expectancy and to placebo effects. The claim that stimulant effects of caffeine are related to withdrawal or withdrawal reversal seems to be untenable.

  3. Caffeine's Influence on Nicotine's Effects in Nonsmokers

    PubMed Central

    Blank, Melissa D.; Kleykamp, Bethea A.; Jennings, Janine M.; Eissenberg, Thomas

    2011-01-01

    Objective To determine if nicotine's effects are influenced by caffeine in nonsmoking, moderate-caffeine consuming individuals (N=20). Methods The first 3 sessions included one of 3 randomly ordered, double-blind caffeine doses (0, 75, or 150 mg, oral [po]) and 2 single-blind nicotine gum doses (2 and 4 mg) in ascending order. The fourth session (single blind) repeated the 0 mg caffeine condition. Results Nicotine increased heart rate and subjective ratings indicative of aversive effects, and decreased reaction times. These effects were independent of caffeine dose and reliable across sessions. Conclusions In nonsmokers, nicotine effects are not influenced by moderate caffeine doses. PMID:17555378

  4. Caffeine fatalities--four case reports.

    PubMed

    Holmgren, Per; Nordén-Pettersson, Lotta; Ahlner, Johan

    2004-01-06

    Four cases of fatal intoxications with caffeine are described. Caffeine is widely available in beverages and in different OTC-products, in many of them in combinations with other drugs like ephedrine. Caffeine is not as harmless as one might believe. An overdose of caffeine alone, intentional or not, might be deadly. It seems to be warranted to include caffeine in the drug-screening of forensic autopsy cases. It is not motivated from a medical point of view to sell pure caffeine over the counter.

  5. Caffeine and the olfactory bulb.

    PubMed

    Hadfield, M G

    1997-08-01

    Caffeine, a popular CNS stimulant, is the most widely used neuroactive drug. Present in coffee, tea, chocolate, and soft drinks as well as over-the-counter and prescription medications, it influences millions of users. This agent has achieved recent notoriety because its dependency consequences and addictive potential have been re-examined and emphasized. Caffeine's central actions are thought to be mediated through adenosine (A) receptors and monoamine neurotransmitters. The present article suggests that the olfactory bulb (OB) may be an important site in the brain that is responsible for caffeine's central actions in several species. This conclusion is based on the extraordinarily robust and selective effects of caffeine on norepinephrine (NE), dopamine (DA), and particularly serotonin (5HT) utilization in the OB of mice. We believe that these phenomena should be given appropriate consideration as a basis for caffeine's central actions, even in primates. Concurrently, we review a rich rodent literature concerned with A, 5HT, NE, and DA receptors in the OB and related structures along with other monoamine parameters. We also review a more limited literature concerned with the primate OB. Finally, we cite the literature that treats the dependency and addictive effects of caffeine in humans, and relate the findings to possible olfactory mechanisms.

  6. Hydration and self-association of caffeine molecules in aqueous solution: Comparative effects of sucrose and β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Mejri, Mondher; BenSouissi, Abdelfattah; Aroulmoji, Vincent; Rogé, Barbara

    2009-07-01

    The UV-spectra of pure caffeine were measured and two quite differentiated hyper- or hypo-chromic effects were observed as concentration was increased. The first one was explained as due to caffeine-water molecule interaction and the second as originating from dimer formation and staking of caffeine molecules. The effects of sucrose and β-cyclodextrin on the hydration and the self-association of caffeine were also examined by UV spectroscopy. Sucrose was found to enhance the self-association of caffeine molecules by attracting and structuring water molecules around itself. The caffeine-caffeine hydrophobic interactions were promoted in such hydrophilic environment and so was the stacking. The molecular aggregation leads to reducing the electronic mobility and so is the case for the mesomeric effect in the heterogeneous cycle. This could explain the hypo-chromic phenomenon observed when sucrose concentration was increased. β-Cyclodextrin shows a distinct behaviour because of its ability to form inclusion complexes with various hydrophobic guest molecules. This ability enhances the solubility of caffeine molecules throughout the inclusion interactions and prevents the caffeine self-association.

  7. Caffeine as a model drug of dependence: recent developments in understanding caffeine withdrawal, the caffeine dependence syndrome, and caffeine negative reinforcement.

    PubMed

    Griffiths, R R; Chausmer, A L

    2000-11-01

    Caffeine is an excellent model compound for understanding drugs of abuse/dependence. The results of self-administration and choice studies in humans clearly demonstrate the reinforcing effects of low and moderate doses of caffeine. Caffeine reinforcement has been demonstrated in about 45% of normal subjects with histories of moderate and heavy caffeine use. Recent studies provide compelling evidence that caffeine physical dependence potentiates the reinforcing effects of caffeine through the mechanism of withdrawal symptom avoidance. Tolerance to the subjective and sleep-disrupting effects of caffeine in humans has been demonstrated. Physical dependence as reflected in a withdrawal syndrome in humans has been repeatedly demonstrated in adults and recently demonstrated in children. Withdrawal severity is an increasing function of caffeine maintenance dose, with withdrawal occurring at doses as low as 100 mg per day. Increased cerebral blood flow may be the physiological mechanism for caffeine withdrawal headache. Case studies in adults and adolescents clearly demonstrate that some individuals meet DSM-IV diagnostic criteria for a substance dependence syndrome on caffeine, including feeling compelled to continue caffeine use despite desires and recommendations to the contrary. Survey data suggest that 9% to 30% percent of caffeine consumers may be caffeine dependent according to DSM-IV criteria.

  8. Epigallocatechin gallate and caffeine differentially inhibit the intestinal absorption of cholesterol and fat in ovariectomized rats.

    PubMed

    Wang, Shu; Noh, Sang K; Koo, Sung I

    2006-11-01

    We conducted this study to determine whether green tea constituents, (-)-epigallocatechin gallate (EGCG) and caffeine, affect the intestinal absorption of cholesterol (CH), fat, and other fat-soluble compounds. Ovariectomized rats with lymph cannula were infused intraduodenally with a lipid emulsion containing 14C-labeled CH (14C-CH), alpha-tocopherol (alpha TOH), triolein, and sodium taurocholate, without (control) or with EGCG, caffeine, or EGCG plus caffeine, in PBS, pH 6.5. The lymphatic total 14C-CH was significantly lowered by EGCG (21.1 +/- 2.1% dose), caffeine (27.9 +/- 1.7% dose), and EGCG plus caffeine (19.3 +/- 0.9% dose), compared with the control (32.4 +/- 1.6% dose). The lymphatic output of esterified CH also was significantly lower in rats infused with EGCG (7.9 +/- 0.7 micromol), caffeine (7.6 +/- 0.2 micromol), and EGCG plus caffeine (7.5 +/- 0.6 micromol) than rats in the control group (11.6 +/- 1.7 micromol). Also, EGCG and caffeine significantly lowered the absorption of alpha TOH, another highly hydrophobic lipid. However, the lymphatic outputs of oleic acid (exogenous fatty acid marker) and other fatty acids of endogenous origin were not affected by EGCG but were markedly lowered by caffeine and EGCG plus caffeine. Caffeine significantly lowered the amount of lymph flow, regardless of whether it was infused alone (14.2 +/- 3.9 mL) or with EGCG (18.6 +/- 2.0 mL), compared with EGCG (22.2 +/- 2.2 mL) alone and the control group (23.2 +/- 3.8 mL). The caffeine-induced decline in lymph flow was associated with the lowering of lipid absorption. The results indicate that both EGCG and caffeine inhibit lipid absorption and that the inhibitory effects of the 2 tea constituents are not synergistic but mediated by distinctly different mechanisms.

  9. Caffeine as an analgesic adjuvant for acute pain in adults.

    PubMed

    Derry, Christopher J; Derry, Sheena; Moore, R Andrew

    2014-12-11

    This is an updated version of the original Cochrane review published in Issue 3, 2012. Caffeine has been added to common analgesics such as paracetamol, ibuprofen, and aspirin, in the belief that it enhances analgesic efficacy. Evidence to support this belief is limited and often based on invalid comparisons. To assess the relative efficacy of a single dose of an analgesic plus caffeine against the same dose of the analgesic alone, without restriction on the analgesic used or the pain condition studied. We also assessed serious adverse events. We searched CENTRAL, MEDLINE, and EMBASE from inception to 28 August 2014, the Oxford Pain Relief Database, and also carried out Internet searches and contacted pharmaceutical companies known to have carried out trials that have not been published. We included randomised, double-blind studies that compared a single dose of analgesic plus caffeine with the same dose of the analgesic alone in the treatment of acute pain. Two review authors independently assessed the eligibility and quality of studies, and extracted data. Any disagreements or uncertainties were settled by discussion with a third review author. We sought any validated measure of analgesic efficacy, but particularly the number of participants experiencing at least 50% of the maximum possible pain relief over four to six hours, participants reporting a global evaluation of treatment of very good or excellent, or headache relief after two hours. We pooled comparable data to look for a statistically significant difference, and calculated numbers needed to treat to benefit (NNT) with caffeine. We also looked for any numerical superiority associated with the addition of caffeine, and information about any serious adverse events. We identified no new studies with available results for this update. The earlier review included 20 studies (7238 participants) in valid comparisons, but because we used different outcomes for some headache studies, the number of participants

  10. Combined effects of caffeine and nicotine on cardiovascular hemodynamics in canine model.

    PubMed

    Jain, A C; Mehta, M C; Billie, M

    1997-05-01

    The independent effects of caffeine and nicotine on cardiodynamics are well documented, but combined effects of both are not reported. Initially, in phase I, 18 experiments were performed to study the dose-response curve of both the drugs. In phases II and III, 13 mongrel dogs were subjected to 30 experiments. In phase II, caffeine, 5 mg/kg, was given i.v. followed by nicotine, 50 micrograms/kg, and in phase III, the sequence of drug administration was reversed to study the effects on hemodynamics. In phase II, caffeine did not show significant changes in all the cardiovascular parameters, but nicotine administration after caffeine produced marked significant synergistic excitatory effects: the rate of increase of the first derivative of left ventricular pressure (dP/dt) increased from 1,101 +/- 111 to 3,194 +/- 872 (p < 0.003). In phase III, nicotine significantly increased heart rate, mean arterial pressures; left ventricular end-diastolic pressure (LVEDP); and pulmonary artery, pulmonary capillary wedge, and right atrial pressures. Nicotine increased dP/dt (964 +/- 182 to 1,639 +/- 60 mm Hg/s; p < 0.004). The excitatory effects of nicotine were attenuated by administration of caffeine (dP/dt, 918 +/- 140 reduced to 715 +/- 144 mm Hg/s; p < 0.04). Caffeine and nicotine, alone, caused nonsignificant and significant increases in hemodynamics, respectively. In combination, caffeine + nicotine administration produced significant synergistic excitatory effects in dogs. On the other hand, the nicotine + caffeine combination caused attenuation by caffeine of the excitatory effects produced by nicotine.

  11. Chronic caffeine administration exacerbates renovascular, but not genetic, hypertension in rats.

    PubMed Central

    Ohnishi, A; Branch, R A; Jackson, K; Hamilton, R; Biaggioni, I; Deray, G; Jackson, E K

    1986-01-01

    The purpose of this study was to determine whether or not caffeine would exacerbate renovascular hypertension. Therefore, we examined the effects of chronic caffeine administration on arterial blood pressure in rats subjected to either unilateral renal artery clipping (2K-1C rats) or sham-operation. Animals in each group were randomly assigned to receive either 0.1% caffeine in their drinking water or normal drinking water, and systolic blood pressure was monitored for 6 wk. Caffeine markedly exacerbated the severity of hypertension in 2K-1C rats and caused histological changes consistent with malignant hypertension. 6 wk after surgery, systolic blood pressure, plasma renin activity, and creatinine clearance in control 2K-1C rats were 169 +/- 5 mmHg (mean +/- SEM), 4.4 +/- 0.5 ng AI X ml-1 X h-1, and 2.9 +/- 0.2 ml/min, respectively; as compared with 219 +/- 4 mmHg, 31.8 +/- 7.8 ng AI X ml-1 X h-1, and 1.4 +/- 0.3 ml/min, respectively, in 2K-1C rats receiving caffeine (all values were significantly different compared with control 2K-1C). Chronic caffeine administration did not alter systolic blood pressure, plasma renin activity, or creatinine clearance in sham-operated rats or spontaneously hypertensive rats. Chronic treatment with enalapril (a converting enzyme inhibitor) prevented the development of hypertension in control 2K-1C rats and caffeine-treated 2K-1C rats; however, withdrawal of enalapril precipitated a rapid rise in systolic blood pressure in caffeine-treated 2K-1C rats, but not in control 2K-1C rats. These experiments indicate that caffeine specifically exacerbates experimental renovascular hypertension and might worsen the hypertensive process in patients with renovascular hypertension. PMID:3020089

  12. Caffeine Intake Among Adolescents in Delhi.

    PubMed

    Gera, Mridul; Kalra, Swati; Gupta, Piyush

    2016-01-01

    Availability and advertising of caffeinated drinks is on the rise in Indian market. Excess caffeine intake may have deleterious effects on health. To estimate the daily consumption of caffeine among urban school-going adolescents from Delhi. A school-based survey was conducted to determine the amount and pattern of caffeine consumption among students of classes 9-12, using a self-administered questionnaire. Of 300 participants (median age 15 year, 174 boys), 291 (97%) were consuming caffeine [mean (SD): 121.0 (98.2) mg/day]. Nineteen (6%) students were consuming more than 300 mg of caffeine per day. Tea/coffee contributed to more than 50% of the caffeine intake. The rest was derived from cola beverages, chocolates, and energy drinks. Average caffeine consumption among school-going adolescents from Delhi is high. The findings of this preliminary survey need to be confirmed in larger data sets.

  13. Caffeine: Can It Help Me Lose Weight?

    MedlinePlus

    ... drinks and colas; in products containing cocoa or chocolate; and in a variety of medications and dietary ... of habitual coffee consumption on cardiometabolic disease, cardiovascular ... B, et al. Benefits and risks of caffeine and caffeinated beverages. http:// ...

  14. Caffeine Intake Among Adolescents in Delhi

    PubMed Central

    Gera, Mridul; Kalra, Swati; Gupta, Piyush

    2016-01-01

    Background: Availability and advertising of caffeinated drinks is on the rise in Indian market. Excess caffeine intake may have deleterious effects on health. Objective: To estimate the daily consumption of caffeine among urban school-going adolescents from Delhi. Materials and Methods: A school-based survey was conducted to determine the amount and pattern of caffeine consumption among students of classes 9-12, using a self-administered questionnaire. Results: Of 300 participants (median age 15 year, 174 boys), 291 (97%) were consuming caffeine [mean (SD): 121.0 (98.2) mg/day]. Nineteen (6%) students were consuming more than 300 mg of caffeine per day. Tea/coffee contributed to more than 50% of the caffeine intake. The rest was derived from cola beverages, chocolates, and energy drinks. Conclusion: Average caffeine consumption among school-going adolescents from Delhi is high. The findings of this preliminary survey need to be confirmed in larger data sets. PMID:27051091

  15. Caffeine: How Much Is Too Much?

    MedlinePlus

    ... travel, stress or too much caffeine — results in sleep deprivation. Sleep loss is cumulative, and even small nightly ... daytime alertness and performance. Using caffeine to mask sleep deprivation can create an unwelcome cycle. For example, you ...

  16. A Comparison of Blue Light and Caffeine Effects on Cognitive Function and Alertness in Humans

    PubMed Central

    Beaven, C. Martyn; Ekström, Johan

    2013-01-01

    The alerting effects of both caffeine and short wavelength (blue) light have been consistently reported. The ability of blue light to enhance alertness and cognitive function via non-image forming neuropathways have been suggested as a non-pharmacological countermeasure for drowsiness across a range of occupational settings. Here we compare and contrast the alerting and psychomotor effects of 240 mg of caffeine and a 1-h dose of ~40 lx blue light in a non-athletic population. Twenty-one healthy subjects performed a computer-based psychomotor vigilance test before and after each of four randomly assigned trial conditions performed on different days: white light/placebo; white light/240 mg caffeine; blue light/placebo; blue light/240 mg caffeine. The Karolinska Sleepiness Scale was used to assess subjective measures of alertness. Both the caffeine only and blue light only conditions enhanced accuracy in a visual reaction test requiring a decision and an additive effect was observed with respect to the fastest reaction times. However, in a test of executive function, where a distraction was included, caffeine exerted a negative effect on accuracy. Furthermore, the blue light only condition consistently outperformed caffeine when both congruent and incongruent distractions were presented. The visual reactions in the absence of a decision or distraction were also enhanced in the blue light only condition and this effect was most prominent in the blue-eyed participants. Overall, blue light and caffeine demonstrated distinct effects on aspects of psychomotor function and have the potential to positively influence a range of settings where cognitive function and alertness are important. Specifically, despite the widespread use of caffeine in competitive sporting environments, the possible impact of blue light has received no research attention. PMID:24282477

  17. The Effects of Caffeine on Vertical Jump Height and Execution in Collegiate Athletes.

    PubMed

    Bloms, Lucas P; Fitzgerald, John S; Short, Martin W; Whitehead, James R

    2016-07-01

    Bloms, LP, Fitzgerald, JS, Short, MW, and Whitehead, JR. The effects of caffeine on vertical jump height and execution in collegiate athletes. J Strength Cond Res 30(7): 1855-1861, 2016-Caffeine ingestion elicits a variety of physiological effects that may be beneficial to maximal-intensity exercise performance, although its effectiveness and physical mechanism of action enhancing ballistic task performance are unclear. The purpose of this study was to examine the effects of caffeine ingestion on vertical jump height and jump execution in Division I collegiate athletes. The study used a single-blind, randomized, crossover design. Athletes (n = 25) consumed either caffeine (5 mg·kg) or placebo. After a 60-minute waiting period, athletes performed 3 squat jumps (SJ) and 3 countermovement jumps (CMJ) while standing on a force platform. Jump height and execution variables were calculated from mechanography data. In comparison with placebo, caffeine increased SJ height (32.8 ± 6.2 vs. 34.5 ± 6.7 cm; p = 0.001) and CMJ height (36.4 ± 6.9 vs. 37.9 ± 7.4 cm; p = 0.001). Peak force (p = 0.032) and average rate of force development (p = 0.037) were increased during the CMJ in the caffeine trail compared with the control. Time to half peak force was the only execution variable improved with caffeine (p = 0.019) during the SJ. It seems that caffeine affects both height and execution of jumping. Our data indicate that the physical mechanism of jump enhancement is increased peak force production or rate of force development during jumping depending on technique. The physical mechanism of jump enhancement suggests that the ergogenic effects of caffeine may transfer to other ballistic tasks involving the lower-body musculature in collegiate athletes.

  18. A comparison of blue light and caffeine effects on cognitive function and alertness in humans.

    PubMed

    Beaven, C Martyn; Ekström, Johan

    2013-01-01

    The alerting effects of both caffeine and short wavelength (blue) light have been consistently reported. The ability of blue light to enhance alertness and cognitive function via non-image forming neuropathways have been suggested as a non-pharmacological countermeasure for drowsiness across a range of occupational settings. Here we compare and contrast the alerting and psychomotor effects of 240 mg of caffeine and a 1-h dose of ~40 lx blue light in a non-athletic population. Twenty-one healthy subjects performed a computer-based psychomotor vigilance test before and after each of four randomly assigned trial conditions performed on different days: white light/placebo; white light/240 mg caffeine; blue light/placebo; blue light/240 mg caffeine. The Karolinska Sleepiness Scale was used to assess subjective measures of alertness. Both the caffeine only and blue light only conditions enhanced accuracy in a visual reaction test requiring a decision and an additive effect was observed with respect to the fastest reaction times. However, in a test of executive function, where a distraction was included, caffeine exerted a negative effect on accuracy. Furthermore, the blue light only condition consistently outperformed caffeine when both congruent and incongruent distractions were presented. The visual reactions in the absence of a decision or distraction were also enhanced in the blue light only condition and this effect was most prominent in the blue-eyed participants. Overall, blue light and caffeine demonstrated distinct effects on aspects of psychomotor function and have the potential to positively influence a range of settings where cognitive function and alertness are important. Specifically, despite the widespread use of caffeine in competitive sporting environments, the possible impact of blue light has received no research attention.

  19. Caffeine in hot drinks elicits cephalic phase responses involving cardiac activity.

    PubMed

    McMullen, Michael K; Whitehouse, Julie M; Shine, Gillian; Whitton, Peter A; Towell, Anthony

    2012-09-01

    Caffeine stimulates both oropharyngeal and gut bitter taste receptors (hTAS2Rs) and so has the potential to elicit reflex autonomic responses. Coffee containing 130 mg caffeine has been reported to increase heart rate for 30 min post-ingestion. Whereas added-caffeine, in doses of 25 to 200 mg, ingested with decaffeinated coffee/tea decreases heart rate 10 to 30 min post-ingestion. This study aimed to clarify caffeine's chemosensory impact. Double-espresso coffees were compared to a placebo-control capsule in a double-blind between-measures design. Coffees tested were regular coffee (130 mg caffeine) and decaffeinated coffee with added-caffeine (0, 67 and 134 mg). Cardiovascular measures from three post-ingestion phases: 1) 0 to 5; 2) 10 to 15; and 3) 25 to 30 min; were compared to pre-ingestion measures. Participants comprised 11 women in the control group and 10 women in the test group. Decaffeinated coffee elicited no changes. Decaffeinated coffee with 67 mg caffeine: decreased dp/dt in Phase 1. Decaffeinated coffee with 134 mg caffeine: increased heart rate in Phases 1 and 2; decreased spontaneous baroreflex sensitivity in Phase 1; and increased diastolic pressure in Phases 2 and 3. Regular coffee: increased heart rate in Phases 1 and 2; decreased dp/dt in all phases; and decreased systolic pressure in Phase 1. Caffeine is the substance in regular coffee which elicits chemosensory autonomic reflex responses, which involves heart activity and the baroreflex. Compared to the caffeine in regular coffee, added-caffeine elicits somewhat different chemosensory responses including a more pronounced pressor effect and resetting of the baroreflex. Caffeine in commonly consumed amounts, as well as modulating body processes by blocking adenosine receptors, can elicit reflex autonomic responses during the ingestion of caffeinated drinks. It is plausible that caffeine stimulates hTAS2Rs, during the ingestion of coffee, eliciting cephalic phase responses. These cephalic phase

  20. Modulatory effects of caffeine on oxidative stress and anxiety-like behavior in ovariectomized rats.

    PubMed

    Caravan, Ionut; Sevastre Berghian, Alexandra; Moldovan, Remus; Decea, Nicoleta; Orasan, Remus; Filip, Gabriela Adriana

    2016-09-01

    Menopause is accompanied by enhanced oxidative stress and behavioral changes, effects attenuated by antioxidants. The aim of this study was to evaluate the effects of caffeine on behavior and oxidative stress in an experimental model of menopause. Female rats were divided into the following groups: sham-operated (CON), sham-operated and caffeine-treated (CAF), ovariectomized (OVX), ovariectomized and caffeine-treated (OVX+CAF). Caffeine (6 mg/kg) and vehicle were administered for 21 days (subchronic) and 42 days (chronic), using 2 experimental subsets. Behavioral tests and oxidative stress parameters in the blood, whole brain, and hippocampus were assessed. The subchronic administration of caffeine decreased the lipid peroxidation and improved the antioxidant defense in the blood and brain. The GSH/GGSG ratio in the brain was improved by chronic administration, with reduced activities of antioxidant enzymes and enhanced nitric oxide and malondialdehyde levels. In particular, the lipid peroxidation in the hippocampus decreased in both experiments. The rats became hyperactive after 21 days of treatment, but no effect was observed after chronic administration. In both experimental subsets, caffeine had anxiolytic effects as tested in elevated plus maze. The administration of low doses of caffeine, for a short period of time, may be a new therapeutic approach to modulating the oxidative stress and anxiety in menopause.

  1. Over-expression of TSC-22 (TGF-beta stimulated clone-22) markedly enhances 5-fluorouracil-induced apoptosis in a human salivary gland cancer cell line.

    PubMed

    Uchida, D; Kawamata, H; Omotehara, F; Miwa, Y; Hino, S; Begum, N M; Yoshida, H; Sato, M

    2000-06-01

    We have recently isolated TSC-22 (transforming growth factor-beta-stimulated clone-22) cDNA as an anticancer, drug-inducible (with vesnarinone) gene in a human salivary gland cancer cell line, TYS. We have also reported that TSC-22 negatively regulates the growth of TYS cells and that down-regulation of TSC-22 in TYS cells plays a major role in salivary gland tumorigenesis (Nakashiro et al, 1998). In this study, we transfected TYS cells with an expression vector encoding the TSC-22-GFP (green fluorescent protein) fusion protein, and we established TSC-22-GFP-expressing TYS cell clones. Next, we examined (a) the subcellular localization of the fusion protein, (b) the sensitivity of the transfectants to several anticancer drugs (5-fluorouracil, cis-diaminedichloroplatinum, peplomycin), and (c) induction of apoptotic cell death in the transfectants by 5-fluorouracil treatment. The TSC-22-GFP fusion protein was clearly localized to the cytoplasm, but not to the nucleus. Over-expression of the TSC-22-GFP fusion protein did not affect cell growth, but significantly increased the sensitivity of the cells to the anticancer drugs (p < 0.01; one-way ANOVA). Furthermore, over-expression of the TSC-22-GFP fusion protein markedly enhanced 5-fluorouracil-induced apoptosis. These findings suggest that over-expression of TSC-22-GFP protein in TYS cells enhances the chemosensitivity of the cells via induction of apoptosis.

  2. Bivalent promoter marks and a latent enhancer may prime the leukaemia oncogene LMO1 for ectopic expression in T-cell leukaemia.

    PubMed

    Oram, S H; Thoms, J; Sive, J I; Calero-Nieto, F J; Kinston, S J; Schütte, J; Knezevic, K; Lock, R B; Pimanda, J E; Göttgens, B

    2013-06-01

    LMO1 is a transcriptional regulator and a T-acute lymphoblastic leukaemia (T-ALL) oncogene. Although first identified in association with a chromosomal translocation in T-ALL, the ectopic expression of LMO1 occurs far more frequently in the absence of any known mutation involving its locus. Given that LMO1 is barely expressed in any haematopoietic lineage, and activation of transcriptional drivers in leukaemic cells is not well described, we investigated the regulation of this gene in normal haematopoietic and leukaemic cells. We show that LMO1 has two promoters that drive reporter gene expression in transgenic mice to neural tissues known to express endogenous LMO1. The LMO1 promoters display bivalent histone marks in multiple blood lineages including T-cells, and a 3' flanking region at LMO1 +57 contains a transcriptional enhancer that is active in developing blood cells in transgenic mouse embryos. The LMO1 promoters become activated in T-ALL together with the 3' enhancer, which is bound in primary T-ALL cells by SCL/TAL1 and GATA3. Taken together, our results show that LMO1 is poised for expression in normal progenitors, where activation of SCL/TAL1 together with a breakdown of epigenetic repression of LMO1 regulatory elements induces ectopic LMO1 expression that contributes to the development and maintenance of T-ALL.

  3. Amplification of steroid-mediated SP-B expression by physiological levels of caffeine.

    PubMed

    Fehrholz, Markus; Hütten, Matthias; Kramer, Boris W; Speer, Christian P; Kunzmann, Steffen

    2014-01-01

    Factors positively influencing surfactant homeostasis in general and surfactant protein B (SP-B) expression in particular are considered of clinical importance regarding an improvement of lung function in preterm infants. The objective of this study was to identify effects of physiological levels of caffeine on glucocorticoid-mediated SP-B expression in vitro and in vivo. Levels of SP-B and pepsinogen C were quantified by quantitative real-time RT-PCR or immunoblotting in NCI-H441 cells daily exposed to caffeine and/or dexamethasone (DEX). In vivo, SP-B expression was analyzed in bronchoalveolar lavage (BAL) of preterm sheep exposed to antenatal DEX and/or postnatal caffeine. If DEX and caffeine were continuously present, SP-B mRNA and protein levels were increased for up to 6 days after induction (P < 0.05). Additionally, caffeine enhanced SP-B mRNA expression in DEX-pretreated cells (P < 0.05). Moreover, caffeine amplified DEX-induced pepsinogen C mRNA expression (P < 0.05). After short-term treatment with caffeine in vivo, only slightly higher SP-B levels could be detected in BAL of preterm sheep following antenatal DEX, combined with an increase of arterial oxygen partial pressure (P < 0.01). Our data demonstrated that the continuous presence of caffeine in vitro is able to amplify DEX-mediated SP-B expression. In contrast, short-term improvement of lung function in vivo is likely to be independent of altered SP-B transcription and translation. An impact of caffeine on release of surfactant reservoirs from lamellar bodies could, however, quickly affect SP-B content in BAL, which has to be further investigated. Our findings indicate that caffeine is able to amplify main effects of glucocorticoids that result from changes in surfactant production, maturation, and release.

  4. Assessment of the Drug-Drug Interaction Potential Between Theacrine and Caffeine in Humans.

    PubMed

    He, Hui; Ma, Dejian; Crone, Laura Brooks; Butawan, Matthew; Meibohm, Bernd; Bloomer, Richard J; Yates, Charles R

    2017-09-01

    Objective: Theacrine, a methylurate class purine alkaloid, triggers diverse pharmacologic responses, including psychostimulatory activity by modulation of adenosinergic and dopaminergic pathways. In a double-blind, placebo-controlled study, theacrine increased energy, concentration, and mood, while reducing fatigue. Because caffeine, a methylxanthine purine alkaloid, is frequently coadministered with theacrine, we sought to determine if a pharmacokinetic and/or pharmacodynamic interaction existed between theacrine and caffeine. Methods: Eight healthy adults received theacrine, as TeaCrine(®) (25 or 125 mg), caffeine (150 mg), or a combination of theacrine (125 mg) and caffeine (150 mg) in a randomized, double-blind crossover study. Blood samples were collected over a 24-hour period and analyzed by Liquid chromatrography-mass spectrometry/mass spectrometry (LC-MS/MS) for theacrine, caffeine, and paraxanthine. Pharmacodynamic response markers, heart rate and blood pressure, were recorded. Results: Theacrine pharmacokinetics was similar following administration of theacrine alone. Caffeine coadministration increased maximum plasma concentration and area under the curve of theacrine without altering theacrine half-life. Theacrine had no impact on caffeine or paraxanthine pharmacokinetics. There was no difference between treatment groups with regard to heart rate or systolic/diastolic blood pressure. Conclusions: Coadministration of theacrine and caffeine results in a clinically significant pharmacokinetic interaction, viz., increased theacrine exposure. Enhanced oral bioavailability is the most likely mechanism by which caffeine alters theacrine exposure. However, further studies examining the contribution of presystemic elimination mechanisms, for example, efflux transport and/or gut metabolism, to theacrine bioavailability are needed to confirm the exact mechanism(s). Hemodynamic parameters were unaltered despite the pharmacokinetic interaction, suggesting

  5. The Effects of Preexercise Caffeinated Coffee Ingestion on Endurance Performance: An Evidence-Based Review.

    PubMed

    Higgins, Simon; Straight, Chad R; Lewis, Richard D

    2016-06-01

    Endurance athletes commonly ingest caffeine as a means to enhance training intensity and competitive performance. A widely-used source of caffeine is coffee, however conflicting evidence exists regarding the efficacy of coffee in improving endurance performance. In this context, the aims of this evidence-based review were threefold: 1) to evaluate the effects of preexercise coffee on endurance performance, 2) to evaluate the effects of coffee on perceived exertion during endurance performance, and 3) to translate the research into usable information for athletes to make an informed decision regarding the intake of caffeine via coffee as a potential ergogenic aid. Searches of three major databases were performed using terms caffeine and coffee, or coffee-caffeine, and endurance, or aerobic. Included studies (n = 9) evaluated the effects of caffeinated coffee on human subjects, provided the caffeine dose administered, administered caffeine ≥ 45 min before testing, and included a measure of endurance performance (e.g., time trial). Significant improvements in endurance performance were observed in five of nine studies, which were on average 24.2% over controls for time to exhaustion trials, and 3.1% for time to completion trials. Three of six studies found that coffee reduced perceived exertion during performance measures significantly more than control conditions (p < .05). Based on the reviewed studies there is moderate evidence supporting the use of coffee as an ergogenic aid to improve performance in endurance cycling and running. Coffee providing 3-8.1 mg/kg (1.36-3.68 mg/lb) of caffeine may be used as a safe alternative to anhydrous caffeine to improve endurance performance.

  6. Minimal effect of acute caffeine ingestion on intense resistance training performance.

    PubMed

    Astorino, Todd A; Martin, Brian J; Schachtsiek, Lena; Wong, Keau; Ng, Karno

    2011-06-01

    The primary aim of the study was to determine the efficacy of acute caffeine intake to enhance intense resistance training performance. Fourteen resistance-trained men (age and body mass = 23.1 ± 1.1 years and 83.4 ± 13.2 kg, respectively) who regularly consumed caffeine ingested caffeine (6 mg · kg(-1)) or placebo 1 hour before completion of 4 sets of barbell bench press, leg press, bilateral row, and barbell shoulder press to fatigue at 70-80% 1-repetition maximum. Two minutes of rest was allotted between sets. Saliva samples were obtained to assess caffeine concentration. The number of repetitions completed per set and total weight lifted were recorded as indices of performance. Two-way analysis of variance with repeated measures was used to examine differences in performance across treatment and sets. Compared to placebo, there was a small but significant effect (p < 0.05) of acute caffeine intake on repetitions completed for the leg press but not for upper-body exercise (p > 0.05). Total weight lifted across sets was similar (p > 0.05) with caffeine (22,409.5 ± 3,773.2 kg) vs. placebo (21,185.7 ± 4,655.4 kg), yet there were 9 'responders' to caffeine, represented by a meaningful increase in total weight lifted with caffeine vs. placebo. Any ergogenic effect of caffeine on performance of fatiguing, total-body resistance training appears to be of limited practical significance. Additional research is merited to elucidate interindividual differences in caffeine-mediated improvements in performance.

  7. A safety assessment of fixed combinations of acetaminophen and acetylsalicylic acid, coformulated with caffeine.

    PubMed

    Bach, P H; Berndt, W O; Delzell, E; Dubach, U; Finn, W F; Fox, J M; Hess, R; Michielsen, P; Sandler, D P; Trump, B; Williams, G

    1998-11-01

    Overuse and abuse of phenacetin-containing mixed analgesics has contributed to end-stage renal disease. Combination analgesics, especially those coformulated with caffeine, have been implicated as imparting a greater risk of analgesic-associated nephropathy (AAN) than single or coformulated analgesics without caffeine. This has led to a recommendation that the sale of "two plus caffeine" analgesic mixtures be reclassified from over-the-counter to prescription only availability. There is a rational basis for coformulating acetylsalicylic acid (ASA) and acetaminophen (paracetamol) as this reduces the dose of each, without altering efficacy. The coformulation of caffeine with these analgesics has a significant adjuvant effect and increases analgesic efficacy 1.4-1.6-fold. Currently available animal and human data do not support the notion that the nephrotoxic risk from coformulated ASA and acetaminophen is higher than the risk from either ASA or acetaminophen alone, in equivalent analgesic doses. There are no epidemiological data that implicate caffeine in AAN, and only limited evidence that links excessive acetaminophen usage to renal disease. There is no evidence that caffeine increases analgesics papillotoxicity directly. The presence of caffeine in mixtures of analgesics are no more addictive than other sources of caffeine. There is no evidence to suggest that adding caffeine to analgesic mixtures enhances the potential for promoting analgesic misuse in the general population. Thus distinct therapeutic benefits of ASA, acetaminophen and caffeine appear to outweigh any known risk. It is doubtful if preventing the availability of these products will significantly affect the role of analgesic abuse/overuse in end-stage renal disease. Better risk management would come from a focused educational program, developed in a close collaboration between industry, healthcare professionals and consumer organizations, such a program must warn against the potential dangers of

  8. Induction of sister chromatid exchange in preimplantation mouse embryos in vitro by /sup 3/H-thymidine or ultraviolet light in combination with caffeine

    SciTech Connect

    Mueller, W.U.S.; Spindle, A.

    1986-01-01

    Preimplantation mouse embryos were exposed in vitro to /sup 3/H-thymidine (25, 100, or 250 Bq/ml) or ultraviolet (UV) light (1.35 or 4.05 J/m2), either alone or in combination with caffeine (1 mM with /sup 3/H-thymidine and 0.5 mM with UV light). Exposure to /sup 3/H-thymidine lasted for 2 days, from the two-cell stage to the late morula/early blastocyst stage, and UV radiation was applied acutely at the late morula/early blastocyst stage. The effects were quantified by the sister chromatid exchange (SCE) assay. All three agents induced SCEs when used singly. /sup 3/H-thymidine was effective in inducing SCEs only at 250 Bq/ml, whereas UV light was effective at both fluences. Although caffeine did not induce SCEs when it was added before exposure to bromodeoxyuridine (BrdUrd), which is used to visualize SCEs, it did induce SCEs when present during the entire culture period (/sup 3/H-thymidine experiments) or during incubation in BrdUrd (UV experiments). Caffeine markedly enhanced the SCE-inducing effect of UV light but did not influence the effect of /sup 3/H-thymidine.

  9. Effects of acute caffeine administration on adolescents.

    PubMed

    Temple, Jennifer L; Dewey, Amber M; Briatico, Laura N

    2010-12-01

    Acute caffeine administration has physiological, behavioral, and subjective effects. Despite its widespread use, few studies have described the impact of caffeine consumption in children and adolescents. The purpose of this study was to investigate the effects of acute caffeine administration in adolescents. We measured cardiovascular responses and snack food intake after acute administration of 0 mg, 50 mg, 100 mg, and 200 mg of caffeine. We also compared usual food intake and subjective effects of caffeine between high- and low-caffeine consumers. Finally, we conducted a detailed analysis of caffeine sources and consumption levels. We found main effects of caffeine dose on heart rate (HR) and diastolic blood pressure (DBP), with HR decreasing and DBP increasing with increasing caffeine dose. There were significant interactions among gender, caffeine use, and time on DBP. High caffeine consumers (>50 mg/day) reported using caffeine to stay awake and drinking coffee, tea, soda, and energy drinks more than low consumers (<50 mg/day). Boys were more likely than girls to report using getting a rush, more energy, or improved athletic performance from caffeine. Finally, when we examined energy and macronutrient intake, we found that caffeine consumption was positively associated with laboratory energy intake, specifically from high-sugar, low-fat foods and also positively associated with protein and fat consumption outside of the laboratory. When taken together, these data suggest that acute caffeine administration has a broad range of effects in adolescents and that the magnitude of these effects is moderated by gender and chronic caffeine consumption.

  10. [EEG spectral analysis of caffeine effects].

    PubMed

    Künkel, H

    1976-01-01

    Spectral EEG analysis is shown to quantify the centrally stimulating effects of caffeine. Comparing the effects of coffee, decaffeinated coffee, caffeine solution and placebo results in two groups of substances: coffee and caffeine solution on one side, decaffeinated coffee and placebo on the other. The within-group differences are negligible, whereas the between-group differences are highly significant. It may be concluded that caffeine is the effective factor. This study gives no valid evidence confirming possible effects of other coffee ingredients.

  11. Caffeine increases striatal dopamine D2/D3 receptor availability in the human brain

    SciTech Connect

    Volkow, N. D.; Wang, G. -J.; Logan, J.; Alexoff, D.; Fowler, J. S.; Thanos, P. K.; Wong, C.; Casado, V.; Ferre, S.; Tomasi, D.

    2015-04-14

    Caffeine, the most widely consumed psychoactive substance in the world, is used to promote wakefulness and enhance alertness. Like other wake-promoting drugs (stimulants and modafinil), caffeine enhances dopamine (DA) signaling in the brain, which it does predominantly by antagonizing adenosine A2A receptors (A2AR). However, it is unclear if caffeine, at the doses consumed by humans, increases DA release or whether it modulates the functions of postsynaptic DA receptors through its interaction with adenosine receptors, which modulate them. We used positron emission tomography and [11C]raclopride (DA D2/D3 receptor radioligand sensitive to endogenous DA) to assess if caffeine increased DA release in striatum in 20 healthy controls. Caffeine (300mg p.o.) significantly increased the availability of D2/D3 receptors in putamen and ventral striatum, but not in caudate, when compared with placebo. In addition, caffeine-induced increases in D2/D3 receptor availability in the ventral striatum were associated with caffeine-induced increases in alertness. Our findings indicate that in the human brain, caffeine, at doses typically consumed, increases the availability of DA D2/D3 receptors, which indicates that caffeine does not increase DA in the striatum for this would have decreased D2/D3 receptor availability. Instead, we interpret our findings to reflect an increase in D2/D3 receptor levels in striatum with caffeine (or changes in affinity). Furthermore, the association between increases in D2/D3 receptor availability in ventral striatum and alertness suggests that caffeine might enhance arousal, in part, by upregulating D2/D3 receptors.

  12. Marked enhancement of the immune response to BioThrax® (Anthrax Vaccine Adsorbed) by the TLR9 agonist CPG 7909 in healthy volunteers.

    PubMed

    Rynkiewicz, Dianna; Rathkopf, Melinda; Sim, Iain; Waytes, A Thomas; Hopkins, Robert J; Giri, Lallan; DeMuria, Deborah; Ransom, Janet; Quinn, James; Nabors, Gary S; Nielsen, Carl J

    2011-08-26

    Immunization with BioThrax(®) (Anthrax Vaccine Adsorbed) is a safe and effective means of preventing anthrax. Animal studies have demonstrated that the addition of CpG DNA adjuvants to BioThrax can markedly increase the immunogenicity of the vaccine, increasing both serum anti-protective antigen (PA) antibody and anthrax toxin-neutralizing antibody (TNA) concentrations. The immune response to CpG-adjuvanted BioThrax in animals was not only stronger, but was also more rapid and led to higher levels of protection in spore challenge models. The B-class CpG DNA adjuvant CPG 7909, a 24-base synthetic, single-strand oligodeoxynucleotide, was evaluated for its safety profile and adjuvant properties in a Phase 1 clinical trial. A double-blind study was performed in which 69 healthy subjects, age 18-45 years, were randomized to receive three doses of either: (1) BioThrax alone, (2) 1 mg of CPG 7909 alone or (3) BioThrax plus 1 mg of CPG 7909, all given intramuscularly on study days 0, 14 and 28. Subjects were monitored for IgG to PA by ELISA and for TNA titers through study day 56 and for safety through month 6. CPG 7909 increased the antibody response by 6-8-fold at peak, and accelerated the response by 3 weeks compared to the response seen in subjects vaccinated with BioThrax alone. No serious adverse events related to study agents were reported, and the combination was considered to be reasonably well tolerated. The marked acceleration and enhancement of the immune response seen by combining BioThrax and CPG 7909 offers the potential to shorten the course of immunization and reduce the time to protection, and may be particularly useful in the setting of post-exposure prophylaxis.

  13. 21 CFR 182.1180 - Caffeine.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Caffeine. 182.1180 Section 182.1180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN....1180 Caffeine. (a) Product. Caffeine. (b) Tolerance. 0.02 percent. (c) Limitations, restrictions,...

  14. Caffeine Use and Young Adult Women.

    ERIC Educational Resources Information Center

    Vener, Arthur M.; Krupka, Lawrence R.

    1982-01-01

    Surveyed college women and men and found that caffeine was consumed by a large proportion of the respondents. Women consumed a larger amount of caffeine and used more substances containing this drug. An increase in caffeine usage with increased psychic stress was observed for women only. (Author)

  15. Influence of mexiletine on caffeine elimination.

    PubMed

    Joeres, R; Klinker, H; Heusler, H; Epping, J; Richter, E

    1987-01-01

    In an acute experiment in healthy volunteers and in patients under long-term treatment for cardiac arrhythmias, mexiletine inhibits caffeine elimination by about 50%. The clearance of mexiletine is not influenced by caffeine. Some side effects of mexiletine may possibly at least partially be attributable to a retention of caffeine.

  16. 21 CFR 182.1180 - Caffeine.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Caffeine. 182.1180 Section 182.1180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Multiple Purpose GRAS Food Substances § 182.1180 Caffeine. (a) Product. Caffeine. (b...

  17. 21 CFR 182.1180 - Caffeine.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Caffeine. 182.1180 Section 182.1180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN....1180 Caffeine. (a) Product. Caffeine. (b) Tolerance. 0.02 percent. (c) Limitations, restrictions,...

  18. 21 CFR 182.1180 - Caffeine.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Caffeine. 182.1180 Section 182.1180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN....1180 Caffeine. (a) Product. Caffeine. (b) Tolerance. 0.02 percent. (c) Limitations, restrictions,...

  19. 21 CFR 182.1180 - Caffeine.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Caffeine. 182.1180 Section 182.1180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN....1180 Caffeine. (a) Product. Caffeine. (b) Tolerance. 0.02 percent. (c) Limitations, restrictions,...

  20. Update on caffeine consumption, disposition and action.

    PubMed

    Mandel, H G

    2002-09-01

    This report represents a current summary of the caffeine contents of various commercial products, and provides data on the spectrum of caffeine intake levels in man. A summary of the substance's pharmacokinetics describes information on its disposition in the body. The effects of caffeine are related to its interaction with adenosine receptors.

  1. Caffeine Use and Young Adult Women.

    ERIC Educational Resources Information Center

    Vener, Arthur M.; Krupka, Lawrence R.

    1982-01-01

    Surveyed college women and men and found that caffeine was consumed by a large proportion of the respondents. Women consumed a larger amount of caffeine and used more substances containing this drug. An increase in caffeine usage with increased psychic stress was observed for women only. (Author)

  2. Caffeine gum minimizes sleep inertia.

    PubMed

    Newman, Rachel A; Kamimori, Gary H; Wesensten, Nancy J; Picchioni, Dante; Balkin, Thomas J

    2013-02-01

    Naps are an effective strategy for maintaining alertness and cognitive performance; however, upon abrupt wakening from naps, sleep inertia (temporary performance degradation) may ensue. In the present study, attenuation of post-nap sleep inertia was attempted by administration of caffeine gum. Using a double-blind, placebo-controlled crossover design, 15 healthy, non-smoking adults were awakened at 1 hr. and again at 6 hr. after lights out (0100 and 0600, respectively) and were immediately administered a gum pellet containing 100 mg of caffeine or placebo. A 5-min. psychomotor vigilance task was administered at 0 min., 6 min., 12 min., and 18 min. post-awakening. At 0100, response speed with caffeine was significantly better at 12 min. and 18 min. post-awakening compared to placebo; at 0600, caffeine's effects were evident at 18 min. post-awakening. Caffeinated gum is a viable means of rapidly attenuating sleep inertia, suggesting that the adenosine receptor system is involved in sleep maintenance.

  3. Caffeine-induced activated glucocorticoid metabolism in the hippocampus causes hypothalamic-pituitary-adrenal axis inhibition in fetal rats.

    PubMed

    Xu, Dan; Zhang, Benjian; Liang, Gai; Ping, Jie; Kou, Hao; Li, Xiaojun; Xiong, Jie; Hu, Dongcai; Chen, Liaobin; Magdalou, Jacques; Wang, Hui

    2012-01-01

    Epidemiological investigations have shown that fetuses with intrauterine growth retardation (IUGR) are susceptible to adult metabolic syndrome. Clinical investigations and experiments have demonstrated that caffeine is a definite inducer of IUGR, as children who ingest caffeine-containing food or drinks are highly susceptible to adult obesity and hypertension. Our goals for this study were to investigate the effect of prenatal caffeine ingestion on the functional development of the fetal hippocampus and the hypothalamic-pituitary-adrenal (HPA) axis and to clarify an intrauterine HPA axis-associated neuroendocrine alteration induced by caffeine. Pregnant Wistar rats were intragastrically administered 20, 60, and 180 mg/kg · d caffeine from gestational days 11-20. The results show that prenatal caffeine ingestion significantly decreased the expression of fetal hypothalamus corticotrophin-releasing hormone. The fetal adrenal cortex changed into slight and the expression of fetal adrenal steroid acute regulatory protein (StAR) and cholesterol side-chain cleavage enzyme (P450scc), as well as the level of fetal adrenal endogenous corticosterone (CORT), were all significantly decreased after caffeine treatment. Moreover, caffeine ingestion significantly increased the levels of maternal and fetal blood CORT and decreased the expression of placental 11β-hydroxysteroid dehydrogenase-2 (11β-HSD-2). Additionally, both in vivo and in vitro studies show that caffeine can downregulate the expression of fetal hippocampal 11β-HSD-2, promote the expression of 11β-hydroxysteroid dehydrogenase 1 and glucocorticoid receptor (GR), and enhance DNA methylation within the hippocampal 11β-HSD-2 promoter. These results suggest that prenatal caffeine ingestion inhibits the development of the fetal HPA axis, which may be associated with the fetal overexposure to maternal glucocorticoid and activated glucocorticoid metabolism in the fetal hippocampus. These results will be beneficial in

  4. Lack of interaction between concurrent caffeine and mobile phone exposure on visual target detection: an ERP study.

    PubMed

    Trunk, Attila; Stefanics, Gábor; Zentai, Norbert; Bacskay, Ivett; Felinger, Attila; Thuróczy, György; Hernádi, István

    2014-09-01

    Caffeine affects information processing by acting predominantly on cortical activation, arousal and attention. Millions consume caffeine and simultaneously use their mobile phone (MP) during everyday activities. However, it is not known whether and how MP-emitted electromagnetic fields (EMFs) can modulate known psychoactive effects of caffeine. Here we investigated behavioral and neural correlates of caffeine and simultaneous MP exposure in a third generation (3G) Universal Mobile Telecommunication System (UMTS) signal modulation scheme. We recorded electroencephalography (EEG) and event related potentials (ERP) in an oddball paradigm to frequent standard (p=0.8) and rare target (p=0.2) stimuli in a placebo controlled, double blind, within-subject protocol in four experimental sessions: 1) no caffeine and no MP, 2) caffeine only, 3) MP only, and 4) caffeine and MP. The subjects' task was to discriminate between standard and target stimuli and respond to the latter by pressing a button while reaction time (RT) and EEG were recorded. To provide a complete analysis of any possible caffeine and/or MP treatment effects that may have occurred, we analyzed the P300 ERP wave using four different ERP measures: 1) peak latency, 2) peak amplitude, 3) 50% fractional area latency (FAL) and 4) area under the curve (AUC). Caffeine significantly shortened RT and decreased AUC of the P300 component compared to the control or the UMTS MP alone conditions. However, no effects were observed on RT or P300 in the UMTS MP exposure sessions, neither alone nor in combination with caffeine. Overall, the present results did not demonstrate any interactive or synergistic effects of caffeine and UMTS MP like EMF exposure on basic neural or cognitive measures. However, we found that caffeine consistently enhanced behavioral and ERP measures of visual target detection, showing that present results were obtained using a pharmacologically validated, consistent and replicable methodology. Copyright

  5. Chronic caffeine treatment prevents stress-induced LTP impairment: the critical role of phosphorylated CaMKII and BDNF.

    PubMed

    Alzoubi, K H; Srivareerat, M; Aleisa, A M; Alkadhi, K A

    2013-01-01

    Caffeine has been reported to enhance cognition in animal and humans. Additionally, caffeine alleviates cognitive impairment associated with a number of disorders including Alzheimer's disease. The lipophilic nature of caffeine allows for rapid absorption into the bloodstream where it freely crosses the blood-brain barrier. Caffeine promotes dendritic spine growth in cultured hippocampal neurons, which suggests a neuroprotective effect. We examined the effect of chronic caffeine treatment on stress-induced suppression of long-term potentiation (LTP) and impairment of molecules of its signaling cascade. Rats were subjected to daily stress using the psychosocial stress paradigm (intruder model), in vivo recordings from area CA1 of the hippocampus of adult rat, and immunoblot analysis of essential signaling molecules. Caffeine prevented stress-induced LTP impairment. Western blot analysis showed reduction of the basal levels of the phosphorylated calcium calmodulin kinase II (P-CAMKII), total CaMKII, and brain-derived neurotrophic factor (BDNF) in area CA1 of stressed rats. These reductions were prevented by chronic caffeine treatment (0.33 mg/L in drinking water). In addition, caffeine prevented the upregulation of calcineurin levels in stressed rats. High-frequency stimulation (HFS) normally increased P-CaMKII, total CaMKII, and calcineurin levels in control as well as in caffeine-treated stressed rats. However, in stressed rats, the same HFS induced increases in the levels of total CaMKII and calcineurin, but not those of P-CaMKII. The levels of signaling molecules may not reflect activities of these molecules. It appears that the neuroprotective effect of caffeine involves preservation of the levels of essential kinases and phosphatases in stressed rats. This may include preservation of basal levels of BDNF by chronic caffeine treatment in stressed animals. These findings highlight the critical role of P-CaMKII and BDNF in caffeine-induced prevention of stress

  6. Caffeine-Induced Activated Glucocorticoid Metabolism in the Hippocampus Causes Hypothalamic-Pituitary-Adrenal Axis Inhibition in Fetal Rats

    PubMed Central

    Xu, Dan; Zhang, Benjian; Liang, Gai; Ping, Jie; Kou, Hao; Li, Xiaojun; Xiong, Jie; Hu, Dongcai; Chen, Liaobin; Magdalou, Jacques; Wang, Hui

    2012-01-01

    Epidemiological investigations have shown that fetuses with intrauterine growth retardation (IUGR) are susceptible to adult metabolic syndrome. Clinical investigations and experiments have demonstrated that caffeine is a definite inducer of IUGR, as children who ingest caffeine-containing food or drinks are highly susceptible to adult obesity and hypertension. Our goals for this study were to investigate the effect of prenatal caffeine ingestion on the functional development of the fetal hippocampus and the hypothalamic-pituitary-adrenal (HPA) axis and to clarify an intrauterine HPA axis-associated neuroendocrine alteration induced by caffeine. Pregnant Wistar rats were intragastrically administered 20, 60, and 180 mg/kg·d caffeine from gestational days 11–20. The results show that prenatal caffeine ingestion significantly decreased the expression of fetal hypothalamus corticotrophin-releasing hormone. The fetal adrenal cortex changed into slight and the expression of fetal adrenal steroid acute regulatory protein (StAR) and cholesterol side-chain cleavage enzyme (P450scc), as well as the level of fetal adrenal endogenous corticosterone (CORT), were all significantly decreased after caffeine treatment. Moreover, caffeine ingestion significantly increased the levels of maternal and fetal blood CORT and decreased the expression of placental 11β-hydroxysteroid dehydrogenase-2 (11β-HSD-2). Additionally, both in vivo and in vitro studies show that caffeine can downregulate the expression of fetal hippocampal 11β-HSD-2, promote the expression of 11β-hydroxysteroid dehydrogenase 1 and glucocorticoid receptor (GR), and enhance DNA methylation within the hippocampal 11β-HSD-2 promoter. These results suggest that prenatal caffeine ingestion inhibits the development of the fetal HPA axis, which may be associated with the fetal overexposure to maternal glucocorticoid and activated glucocorticoid metabolism in the fetal hippocampus. These results will be beneficial in

  7. Concentration- and age-dependent effects of chronic caffeine on contextual fear conditioning in C57BL/6J mice.

    PubMed

    Poole, Rachel L; Braak, David; Gould, Thomas J

    2016-02-01

    Chronic caffeine exerts negligible effects on learning and memory in normal adults, but it is unknown whether this is also true for children and adolescents. The hippocampus, a brain region important for learning and memory, undergoes extensive structural and functional modifications during pre-adolescence and adolescence. As a result, chronic caffeine may have differential effects on hippocampus-dependent learning in pre-adolescents and adolescents compared with adults. Here, we characterized the effects of chronic caffeine and withdrawal from chronic caffeine on hippocampus-dependent (contextual) and hippocampus-independent (cued) fear conditioning in pre-adolescent, adolescent, and adult mice. The results indicate that chronic exposure to caffeine during pre-adolescence and adolescence enhances or impairs contextual conditioning depending on concentration, yet has no effect on cued conditioning. In contrast, withdrawal from chronic caffeine impairs contextual conditioning in pre-adolescent mice only. No changes in learning were seen for adult mice for either the chronic caffeine or withdrawal conditions. These findings support the hypothesis that chronic exposure to caffeine during pre-adolescence and adolescence can alter learning and memory and as changes were only seen in hippocampus-dependent learning, which suggests that the developing hippocampus may be sensitive to the effects of caffeine.

  8. Concentration- and age-dependent effects of chronic caffeine on contextual fear conditioning in C57BL/6J mice

    PubMed Central

    Poole, Rachel L.; Braak, David; Gould, Thomas J.

    2015-01-01

    Chronic caffeine exerts negligible effects on learning and memory in normal adults, but it is unknown whether this is also true for children and adolescents. The hippocampus, a brain region important for learning and memory, undergoes extensive structural and functional modifications during pre-adolescence and adolescence. As a result, chronic caffeine may have differential effects on hippocampus-dependent learning in pre-adolescents and adolescents compared with adults. Here, we characterized the effects of chronic caffeine and withdrawal from chronic caffeine on hippocampus-dependent (contextual) and hippocampus-independent (cued) fear conditioning in pre-adolescent, adolescent, and adult mice. The results indicate that chronic exposure to caffeine during pre-adolescence and adolescence enhances or impairs contextual conditioning depending on concentration, yet has no effect on cued conditioning. In contrast, withdrawal from chronic caffeine impairs contextual conditioning in pre-adolescent mice only. No changes in learning were seen for adult mice for either the chronic caffeine or withdrawal conditions. These findings support the hypothesis that chronic exposure to caffeine during pre-adolescence and adolescence can alter learning and memory and as changes were only seen in hippocampus-dependent learning, this suggests that the developing hippocampus may be sensitive to the effects of caffeine. PMID:25827925

  9. Prenatal caffeine ingestion induces transgenerational neuroendocrine metabolic programming alteration in second generation rats

    SciTech Connect

    Luo, Hanwen; Deng, Zixin; Liu, Lian; Shen, Lang; Kou, Hao; He, Zheng; Ping, Jie; Xu, Dan; Ma, Lu; Chen, Liaobin; Wang, Hui

    2014-02-01

    Our previous studies have demonstrated that prenatal caffeine ingestion induces an increased susceptibility to metabolic syndrome with alterations of glucose and lipid metabolic phenotypes in adult first generation (F1) of intrauterine growth retardation (IUGR) rats, and the underlying mechanism is originated from a hypothalamic–pituitary–adrenal (HPA) axis-associated neuroendocrine metabolic programming alteration in utero. This study aims to investigate the transgenerational effects of this programming alteration in adult second generation (F2). Pregnant Wistar rats were administered with caffeine (120 mg/kg·d) from gestational day 11 until delivery. Four groups in F2 were set according to the cross-mating between control and caffeine-induced IUGR rats. F2 were subjected to a fortnight ice water swimming stimulus on postnatal month 4, and blood samples were collected before and after stress. Results showed that the majority of the activities of HPA axis and phenotypes of glucose and lipid metabolism were altered in F2. Particularly, comparing with the control group, caffeine groups had an enhanced corticosterone levels after chronic stress. Compared with before stress, the serum glucose levels were increased in some groups whereas the triglyceride levels were decreased. Furthermore, total cholesterol gain rates were enhanced but the high-density lipoprotein-cholesterol gain rates were decreased in most caffeine groups after stress. These transgenerational effects were characterized partially with gender and parental differences. Taken together, these results indicate that the reproductive and developmental toxicities and the neuroendocrine metabolic programming mechanism by prenatal caffeine ingestion have transgenerational effects in rats, which may help to explain the susceptibility to metabolic syndrome and associated diseases in F2. - Highlights: • Caffeine-induced neuroendocrine metabolic programming of HPA has hereditary effect. • Caffeine

  10. Caffeine-induced psychiatric manifestations: a review.

    PubMed

    Wang, Hee Ryung; Woo, Young Sup; Bahk, Won-Myong

    2015-07-01

    The association between caffeine consumption and various psychiatric manifestations has long been observed. We present two cases that show the ability of caffeine to induce psychotic and manic symptoms, and we also review the extant literature on caffeine-induced psychiatric manifestations. On the basis of our own and others' findings, we suggest that caffeine may be related to not only de-novo psychotic or mood symptoms but also to aggravation of pre-existing psychotic or mood disorders. We therefore suggest that caffeine consumption among patients with mood or psychotic symptoms should be assessed carefully in clinical practice as part of routine psychiatric evaluations.

  11. Caffeine in the treatment of pain.

    PubMed

    Tavares, Cristiane; Sakata, Rioko Kimiko

    2012-01-01

    Caffeine is a widely used substance with effects on several systems, presenting characteristic of pharmacokinetic and pharmacodynamic which cause interactions with several drugs. This study's objective is to review the effects caused by caffeine. This review assesses the caffeine pharmacology, its action mechanisms, indications, contraindications, doses, interactions and adverse effects. There are insufficient double-blind randomized controlled studies that assess the analgesic effect of caffeine on several painful syndromes. Patients presenting chronic pain need caution when it comes to tolerance development, abstinence and drug interaction from chronic caffeine use. Copyright © 2012 Elsevier Editora Ltda. All rights reserved.

  12. Genome-wide association study of caffeine metabolites provides new insights to caffeine metabolism and dietary caffeine-consumption behavior.

    PubMed

    Cornelis, Marilyn C; Kacprowski, Tim; Menni, Cristina; Gustafsson, Stefan; Pivin, Edward; Adamski, Jerzy; Artati, Anna; Eap, Chin B; Ehret, Georg; Friedrich, Nele; Ganna, Andrea; Guessous, Idris; Homuth, Georg; Lind, Lars; Magnusson, Patrik K; Mangino, Massimo; Pedersen, Nancy L; Pietzner, Maik; Suhre, Karsten; Völzke, Henry; Bochud, Murielle; Spector, Tim D; Grabe, Hans J; Ingelsson, Erik

    2016-10-03

    Caffeine is the most widely consumed psychoactive substance in the world and presents with wide interindividual variation in metabolism. This variation may modify potential adverse or beneficial effects of caffeine on health. We conducted a genome-wide association study (GWAS) of plasma caffeine, paraxanthine, theophylline, theobromine and paraxanthine/caffeine ratio among up to 9,876 individuals of European ancestry from six population-based studies. A single SNP at 6p23 (near CD83) and several SNPs at 7p21 (near AHR), 15q24 (near CYP1A2) and 19q13.2 (near CYP2A6) met GW-significance (P < 5 × 10(-8)) and were associated with one or more metabolites. Variants at 7p21 and 15q24 associated with higher plasma caffeine and lower plasma paraxanthine/caffeine (slow caffeine metabolism) were previously associated with lower coffee and caffeine consumption behavior in GWAS. Variants at 19q13.2 associated with higher plasma paraxanthine/caffeine (slow paraxanthine metabolism) were also associated with lower coffee consumption in the UK Biobank (n = 94 343, P < 1.0 × 10(-6)). Variants at 2p24 (in GCKR), 4q22 (in ABCG2) and 7q11.23 (near POR) that were previously associated with coffee consumption in GWAS were nominally associated with plasma caffeine or its metabolites. Taken together, we have identified genetic factors contributing to variation in caffeine metabolism and confirm an important modulating role of systemic caffeine levels in dietary caffeine consumption behavior. Moreover, candidate genes identified encode proteins with important clinical functions that extend beyond caffeine metabolism.

  13. Caffeine during pregnancy? In moderation.

    PubMed Central

    Koren, G.

    2000-01-01

    QUESTION: Many of my female patients, those who plan pregnancy or have conceived, are afraid of any intake of caffeine. This often makes their lives miserable during pregnancy. Is this justified scientifically? ANSWER: Motherisk's recent meta-analysis suggests that the risks for miscarriage and fetal growth retardation increase only with daily doses of caffeine above 150 mg/d, equivalent to six typical cups of coffee a day. It is possible that some of this presumed risk is due to confounders, such as cigarette smoking. PMID:10790810

  14. Single Ryanodine Receptor Channel Basis of Caffeine's Action on Ca2+ Sparks

    PubMed Central

    Porta, Maura; Zima, Aleksey V.; Nani, Alma; Diaz-Sylvester, Paula L.; Copello, Julio A.; Ramos-Franco, Josefina; Blatter, Lothar A.; Fill, Michael

    2011-01-01

    Caffeine (1, 3, 7-trimethylxanthine) is a widely used pharmacological agonist of the cardiac ryanodine receptor (RyR2) Ca2+ release channel. It is also a well-known stimulant that can produce adverse side effects, including arrhythmias. Here, the action of caffeine on single RyR2 channels in bilayers and Ca2+ sparks in permeabilized ventricular cardiomyocytes is defined. Single RyR2 caffeine activation depended on the free Ca2+ level on both sides of the channel. Cytosolic Ca2+ enhanced RyR2 caffeine affinity, whereas luminal Ca2+ essentially scaled maximal caffeine activation. Caffeine activated single RyR2 channels in diastolic quasi-cell-like solutions (cytosolic MgATP, pCa 7) with an EC50 of 9.0 ± 0.4 mM. Low-dose caffeine (0.15 mM) increased Ca2+ spark frequency ∼75% and single RyR2 opening frequency ∼150%. This implies that not all spontaneous RyR2 openings during diastole are associated with Ca2+ sparks. Assuming that only the longest openings evoke sparks, our data suggest that a spark may result only when a spontaneous single RyR2 opening lasts >6 ms. PMID:21320437

  15. What can isolated skeletal muscle experiments tell us about the effects of caffeine on exercise performance?

    PubMed Central

    Tallis, Jason; Duncan, Michael J; James, Rob S

    2015-01-01

    Caffeine is an increasingly popular nutritional supplement due to the legal, significant improvements in sporting performance that it has been documented to elicit, with minimal side effects. Therefore, the effects of caffeine on human performance continue to be a popular area of research as we strive to improve our understanding of this drug and make more precise recommendations for its use in sport. Although variations in exercise intensity seems to affect its ergogenic benefits, it is largely thought that caffeine can induce significant improvements in endurance, power and strength-based activities. There are a number of limitations to testing caffeine-induced effects on human performance that can be better controlled when investigating its effects on isolated muscles under in vitro conditions. The hydrophobic nature of caffeine results in a post-digestion distribution to all tissues of the body making it difficult to accurately quantify its key mechanism of action. This review considers the contribution of evidence from isolated muscle studies to our understating of the direct effects of caffeine on muscle during human performance. The body of in vitro evidence presented suggests that caffeine can directly potentiate skeletal muscle force, work and power, which may be important contributors to the performance-enhancing effects seen in humans. PMID:25988508

  16. What can isolated skeletal muscle experiments tell us about the effects of caffeine on exercise performance?

    PubMed

    Tallis, Jason; Duncan, Michael J; James, Rob S

    2015-08-01

    Caffeine is an increasingly popular nutritional supplement due to the legal, significant improvements in sporting performance that it has been documented to elicit, with minimal side effects. Therefore, the effects of caffeine on human performance continue to be a popular area of research as we strive to improve our understanding of this drug and make more precise recommendations for its use in sport. Although variations in exercise intensity seems to affect its ergogenic benefits, it is largely thought that caffeine can induce significant improvements in endurance, power and strength-based activities. There are a number of limitations to testing caffeine-induced effects on human performance that can be better controlled when investigating its effects on isolated muscles under in vitro conditions. The hydrophobic nature of caffeine results in a post-digestion distribution to all tissues of the body making it difficult to accurately quantify its key mechanism of action. This review considers the contribution of evidence from isolated muscle studies to our understating of the direct effects of caffeine on muscle during human performance. The body of in vitro evidence presented suggests that caffeine can directly potentiate skeletal muscle force, work and power, which may be important contributors to the performance-enhancing effects seen in humans.

  17. Caffeine Induces the Stress Response and Up-Regulates Heat Shock Proteins in Caenorhabditis elegans.

    PubMed

    Al-Amin, Mohammad; Kawasaki, Ichiro; Gong, Joomi; Shim, Yhong-Hee

    2016-02-01

    Caffeine has both positive and negative effects on physiological functions in a dose-dependent manner. C. elegans has been used as an animal model to investigate the effects of caffeine on development. Caffeine treatment at a high dose (30 mM) showed detrimental effects and caused early larval arrest. We performed a comparative proteomic analysis to investigate the mode of action of high-dose caffeine treatment in C. elegans and found that the stress response proteins, heat shock protein (HSP)-4 (endoplasmic reticulum [ER] chaperone), HSP-6 (mitochondrial chaperone), and HSP-16 (cytosolic chaperone), were induced and their expression was regulated at the transcriptional level. These findings suggest that high-dose caffeine intake causes a strong stress response and activates all three stress-response pathways in the worms, including the ER-, mitochondrial-, and cytosolic pathways. RNA interference of each hsp gene or in triple combination retarded growth. In addition, caffeine treatment stimulated a food-avoidance behavior (aversion phenotype), which was enhanced by RNAi depletion of the hsp-4 gene. Therefore, up-regulation of hsp genes after caffeine treatment appeared to be the major responses to alleviate stress and protect against developmental arrest.

  18. Ephedrine plus caffeine causes age-dependent cardiovascular responses in Fischer 344 rats.

    PubMed

    Howden, Reuben; Hanlon, Paul R; Petranka, John G; Kleeberger, Steven; Bucher, John; Dunnick, June; Nyska, Abraham; Murphy, Elizabeth

    2005-05-01

    Human consumption of ephedrine and caffeine in dietary supplements has been associated with a number of adverse effects including changes in the ECG, myocardial infarction, hyperthermia, and, in rare instances, death. The purpose of this study was to investigate the potential mechanisms associated with the cardiotoxicity of combined ephedrine and caffeine ingestion. Seven- and fourteen-week-old Fischer 344 rats treated with ephedrine in combination with caffeine exhibited increases in heart rate (HR), temperature, and corrected QT interval. Of the 14-wk-old rats treated with 25 mg/kg ephedrine plus 30 mg/kg caffeine, 57% died within 3-5 h of treatment, whereas none of the similarly treated 7-wk-old rats nor any of the rats treated with vehicle died. One hour after treatment with this dose of ephedrine plus caffeine, 14-wk-old rats exhibited a larger increase in HR (as % increase over baseline) than 7-wk-old rats. Furthermore, the 14-wk-old rats that died had a higher HR and temperature than the 14-wk-old rats that lived. Histopathological studies suggested interstitial hemorrhage and myofiber necrosis in the 14-wk-old rats treated with the highest concentration of ephedrine and caffeine. This study showed enhanced susceptibility to ephedrine plus caffeine in 14-wk-old rats compared with 7-wk-old rats. The greater mortality in the 14-wk-old rats was associated with increases in body temperature, HR, and myocardial necrosis.

  19. Caffeine Induces the Stress Response and Up-Regulates Heat Shock Proteins in Caenorhabditis elegans

    PubMed Central

    Al-Amin, Mohammad; Kawasaki, Ichiro; Gong, Joomi; Shim, Yhong-Hee

    2016-01-01

    Caffeine has both positive and negative effects on physiological functions in a dose-dependent manner. C. elegans has been used as an animal model to investigate the effects of caffeine on development. Caffeine treatment at a high dose (30 mM) showed detrimental effects and caused early larval arrest. We performed a comparative proteomic analysis to investigate the mode of action of high-dose caffeine treatment in C. elegans and found that the stress response proteins, heat shock protein (HSP)-4 (endoplasmic reticulum [ER] chaperone), HSP-6 (mitochondrial chaperone), and HSP-16 (cytosolic chaperone), were induced and their expression was regulated at the transcriptional level. These findings suggest that high-dose caffeine intake causes a strong stress response and activates all three stress-response pathways in the worms, including the ER-, mitochondrial-, and cytosolic pathways. RNA interference of each hsp gene or in triple combination retarded growth. In addition, caffeine treatment stimulated a food-avoidance behavior (aversion phenotype), which was enhanced by RNAi depletion of the hsp-4 gene. Therefore, up-regulation of hsp genes after caffeine treatment appeared to be the major responses to alleviate stress and protect against developmental arrest. PMID:26743903

  20. Caffeine prevents changes in muscle caused by high-intensity interval training.

    PubMed

    Vieira, Juliano M; Gutierres, Jessié M; Carvalho, Fabiano B; Pereira, Luciane B; Oliveira, Liziele S; Morsch, Vera Maria; Schetinger, Maria Rosa C; Rodrigues, Marília V; Leitemperger, Jossiele; Loro, Vânia; Krewer, Cristina C; Vencato, Marina S; Spanevello, Roselia M

    2017-02-17

    The use of ergogenic substances such as caffeine has become a strategy to enhance sports performance. In the present study we evaluated the effects of high-intensity interval training (HIIT) associated with caffeine intake on acetylcholinesterase (AChE) and Ca(2+)ATPase activity and glycogen levels in the muscles of rats were evaluated. The animals were divided in groups: control, caffeine 4 or 8mg/kg, HIIT, HIIT plus caffeine 4 or caffeine 8mg/kg. Our results showed a decrease in glycogen levels in muscle in all trained groups after acute session exercise, while that an increase in glycogen levels was observed in all groups in relation to control in chronic exercise protocol. HIIT increases the thickness of the left ventricle and the Ca(2+)-ATPase activity and decrease the AChE activity in gastrocnemius muscle. Caffeine treatment prevents changes in enzymes activities as well as left ventricular hypertrophy adaptation induced by HIIT. Our findings suggest that caffeine modulates crucial pathways for muscle contraction in HIIT.

  1. Neuroprotection by caffeine and A(2A) adenosine receptor inactivation in a model of Parkinson's disease.

    PubMed

    Chen, J F; Xu, K; Petzer, J P; Staal, R; Xu, Y H; Beilstein, M; Sonsalla, P K; Castagnoli, K; Castagnoli, N; Schwarzschild, M A

    2001-05-15

    Recent epidemiological studies have established an association between the common consumption of coffee or other caffeinated beverages and a reduced risk of developing Parkinson's disease (PD). To explore the possibility that caffeine helps prevent the dopaminergic deficits characteristic of PD, we investigated the effects of caffeine and the adenosine receptor subtypes through which it may act in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxin model of PD. Caffeine, at doses comparable to those of typical human exposure, attenuated MPTP-induced loss of striatal dopamine and dopamine transporter binding sites. The effects of caffeine were mimicked by several A(2A) antagonists (7-(2-phenylethyl)-5-amino-2-(2-furyl)-pyrazolo-[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine (SCH 58261), 3,7-dimethyl-1-propargylxanthine, and (E)-1,3-diethyl-8 (KW-6002)-(3,4-dimethoxystyryl)-7-methyl-3,7-dihydro-1H-purine-2,6-dione) (KW-6002) and by genetic inactivation of the A(2A) receptor, but not by A(1) receptor blockade with 8-cyclopentyl-1,3-dipropylxanthine, suggesting that caffeine attenuates MPTP toxicity by A(2A) receptor blockade. These data establish a potential neural basis for the inverse association of caffeine with the development of PD, and they enhance the potential of A(2A) antagonists as a novel treatment for this neurodegenerative disease.

  2. Single ryanodine receptor channel basis of caffeine's action on Ca2+ sparks.

    PubMed

    Porta, Maura; Zima, Aleksey V; Nani, Alma; Diaz-Sylvester, Paula L; Copello, Julio A; Ramos-Franco, Josefina; Blatter, Lothar A; Fill, Michael

    2011-02-16

    Caffeine (1, 3, 7-trimethylxanthine) is a widely used pharmacological agonist of the cardiac ryanodine receptor (RyR2) Ca(2+) release channel. It is also a well-known stimulant that can produce adverse side effects, including arrhythmias. Here, the action of caffeine on single RyR2 channels in bilayers and Ca(2+) sparks in permeabilized ventricular cardiomyocytes is defined. Single RyR2 caffeine activation depended on the free Ca(2+) level on both sides of the channel. Cytosolic Ca(2+) enhanced RyR2 caffeine affinity, whereas luminal Ca(2+) essentially scaled maximal caffeine activation. Caffeine activated single RyR2 channels in diastolic quasi-cell-like solutions (cytosolic MgATP, pCa 7) with an EC(50) of 9.0 ± 0.4 mM. Low-dose caffeine (0.15 mM) increased Ca(2+) spark frequency ∼75% and single RyR2 opening frequency ∼150%. This implies that not all spontaneous RyR2 openings during diastole are associated with Ca(2+) sparks. Assuming that only the longest openings evoke sparks, our data suggest that a spark may result only when a spontaneous single RyR2 opening lasts >6 ms. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  3. Depressing effects of caffeine at crayfish neuromuscular synapses I. Dosage response and Ca++ gradient effects.

    PubMed

    Judd, Kristin; Shugert, Elizabeth; Vélez, Samuel J

    2007-05-01

    The response of crayfish synaptic terminals to drugs began to be studied to characterize the terminal's physiological characteristics. Caffeine, the first drug to be studied, was selected to enhance synaptic transmission because of its ability to increase calcium release from internal stores.1. The largest excitor neuron to the superficial flexor muscle system of Procambarus clarkii was stimulated at 10 Hz while recording junction potentials from several lateral muscle fibers.2. Caffeine unexpectedly decreased synaptic transmission in this system in a dosage-dependent manner. The depressing effect of caffeine was observed at 5 mM caffeine and junction potentials disappeared completely at 50 mM. Washing the preparation in fresh control Ringers did not restore the amplitudes of the junction potentials.3. Changes in extracellular calcium concentrations delayed or depressed the caffeine effect depending on the calcium gradient across the membrane or the caffeine dosage. The data suggest that calcium is involved in caffeine's response in this system in a way yet to be determined.

  4. Itraconazole, a P-glycoprotein and CYP3A4 inhibitor, markedly raises the plasma concentrations and enhances the renin-inhibiting effect of aliskiren.

    PubMed

    Tapaninen, Tuija; Backman, Janne T; Kurkinen, Kaisa J; Neuvonen, Pertti J; Niemi, Mikko

    2011-03-01

    In a randomized crossover study, 11 healthy volunteers took 100 mg (first dose 200 mg) of the antifungal drug itraconazole, a P-glycoprotein and CYP3A4 inhibitor, or placebo twice daily for 5 days. On day 3, they ingested a single 150-mg dose of aliskiren, a renin inhibitor used in the treatment of hypertension. Itraconazole raised the peak plasma aliskiren concentration 5.8-fold (range, 1.1- to 24.3-fold; P < .001) and the area under the plasma aliskiren concentration-time curve 6.5-fold (range, 2.6- to 20.5-fold; P < .001) but had no significant effect on aliskiren elimination half-life. Itraconazole increased the amount of aliskiren excreted into the urine during 12 hours 8.0-fold (P < .001) and its renal clearance 1.2-fold (P = .042). Plasma renin activity 24 hours after aliskiren intake was 68% lower during the itraconazole phase than during the placebo phase (P = .011). In conclusion, itraconazole markedly raises the plasma concentrations and enhances the renin-inhibiting effect of aliskiren. The interaction is probably mainly explained by inhibition of the P-glycoprotein-mediated efflux of aliskiren in the small intestine, with a minor contribution from inhibition of CYP3A4. Concomitant use of aliskiren and itraconazole is best avoided.

  5. Effects of chronic administration of caffeine and stress on feeding behavior of rats.

    PubMed

    Pettenuzzo, Leticia Ferreira; Noschang, Cristie; von Pozzer Toigo, Eduardo; Fachin, Andrelisa; Vendite, Deusa; Dalmaz, Carla

    2008-10-20

    Anorectic effects of caffeine are controversial in the literature, while stress and obesity are growing problems in our society. Since many stressed people are coffee drinkers, the objective of the present study was to evaluate the effect of stress and chronic administration of caffeine on feeding behavior and body weight in male and female rats. Wistar rats (both males and females) were divided into 3 groups: control (receiving water), caffeine 0.3 g/L and caffeine 1.0 g/L (in the drinking water). These groups were subdivided into non-stressed and stressed (repeated-restraint stress for 40 days). During the entire treatment, chow consumption was monitored and rats were weighed monthly. Afterwards, feeding behavior was evaluated during 3-min trials in food-deprived and ad libitum fed animals and also in repeated exposures, using palatable food (Froot Loops and Cheetos). Chronic administration of caffeine did not affect rat chow consumption or body weight gain, but diminished the consumption of both salty (Cheetos) and sweet (Froot Loops) palatable food. In the repeated trial tests, stress diminished savory snack consumption in the later exposures [I.S. Racotta, J. Leblanc, D. Richard The effect of caffeine on food intake in rats: involvement of corticotropin-releasing factor and the sympatho-adrenal system. Pharmacol Biochem Behav. 1994, 48:887-892; S.D. Comer, M. Haney, R.W. Foltin, M.W. Fischman Effects of caffeine withdrawal on humans living in a residential laboratory. Exp Clin Psychopharmacol. 1997, 5:399-403; A. Jessen, B. Buemann, S. Toubro, I.M. Skovgaard, A. Astrup The appetite-suppressant effect of nicotine is enhanced by caffeine. Diab Ob Metab. 2005, 7:327-333; J.M. Carney Effects of caffeine, theophylline and theobromine on scheduled controlled responding in rats. Br J Pharmacol. 1982, 75:451-454] and caffeine diminished consumption of both palatable foods (savory and sweet) during the early and later exposures. Most responses to caffeine were stronger

  6. Overnight caffeine abstinence and negative reinforcement of preference for caffeine-containing drinks.

    PubMed

    Rogers, P J; Richardson, N J; Elliman, N A

    1995-08-01

    It has been suggested that liking for the taste, flavour and aroma of, for example, coffee and tea is acquired through the process of classical conditioning, involving association of these orosensory cues with the psychopharmacological consequences of caffeine ingestion. Accordingly, this study investigated caffeine reinforcement by assessing changes in preference for a novel drink consumed with or without caffeine. Particular care was taken to use "ecologically valid" procedures; that is, overnight caffeine abstinence followed by a cup-of-coffee equivalent dose of caffeine (70 mg) at breakfast. Caffeine had no significant effects on drink preference or mood in subjects with habitually low intakes of caffeine. In contrast, moderate users of caffeine developed a relative dislike for the drink lacking caffeine and showed somewhat lowered mood following overnight caffeine abstinence (e.g., less lively, clearheaded and cheerful), which was significantly improved by caffeine. These together with other recent results strongly suggest that, in everyday life, caffeine reinforcement can occur as the result of the alleviation by caffeine of the adverse effects of overnight caffeine abstinence (negative reinforcement). They also demonstrate the utility of this flavour-conditioning procedure, which could be applied in the wider investigation of the reinforcing properties of drugs.

  7. Investigating the effects of caffeine on phonation.

    PubMed

    Erickson-Levendoski, Elizabeth; Sivasankar, Mahalakshmi

    2011-09-01

    A core component of vocal hygiene programs is the avoidance of agents that may dry the vocal folds. Clinicians commonly recommend that individuals reduce caffeine intake because of its presumed dehydrating effects on the voice. However, there is little evidence that ingestion of caffeine is detrimental to voice production. The first objective of this study was to evaluate whether caffeine adversely affects voice production. The second objective was to evaluate if caffeine exacerbates the adverse phonatory effects of vocal loading. Prospective, double-blinded, sham-controlled study. Sixteen healthy adults participated in two sessions where they consumed caffeine (caffeine concentration=480 mg) or sham (caffeine concentration=24 mg) beverages. Voice measures (phonation threshold pressure and perceived phonatory effort) were collected. Subjects then completed a vocal loading challenge and voice measures were obtained again. There were no significant differences in voice measures between the caffeine and sham conditions. Ingestion of caffeine did not adversely affect voice production (P>0.05) or exacerbate the detrimental phonatory effects of vocal loading (P>0.05). Our findings contribute to emerging knowledge on the effects of caffeine on voice production. Recommendations to completely eliminate caffeine from the diet, as a component of a vocal hygiene program, should be evaluated on an individual basis. Copyright © 2011 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  8. Caffeine: implications for alertness in athletes.

    PubMed

    Rogers, Naomi L; Dinges, David F

    2005-04-01

    Caffeine is one of the most widely consumed drugs in the world, taken socially and for its alertness- and performance-promoting actions. Extensive reports assert that caffeine increases alertness and cognitive performance levels and, when taken before exercise, demonstrates ergogenic properties. Caffeine ingestion has been associated with increased performance during endurance submaximal, and acute, high-intensity exercise. The exact mechanism of action for the performance effects of caffeine is unknown, although several physiologically and psychologically based theories exist as to how caffeine achieves increased performance capabilities. This paper outlines the known sites of caffeine activity in the body,and discusses these with respect to the effects of caffeine observed during performance assessments.

  9. Clinical and Physiological Correlates of Caffeine and Caffeine Metabolites in Primary Insomnia

    PubMed Central

    Youngberg, Mark R.; Karpov, Irina O.; Begley, Amy; Pollock, Bruce G.; Buysse, Daniel J.

    2011-01-01

    Objectives: To explore the relationship between plasma concentrations of caffeine and subjective and polysomnographic measures of sleep in both good sleeper controls (GSC) and individuals with primary insomnia (PI), following the consumption of low-moderate quantities of caffeine in the home environment. Methods: 65 PI and 29 GSC, each consuming < 4 four coffee cup equivalents of caffeine daily, were recruited. Subjects completed a diary detailing sleep habits and caffeine consumption, one night of polysomnography, and a blood sample for measurement of plasma caffeine and its metabolites at bedtime. Plasma concentrations of caffeine, its primary metabolite, paraxanthine, and other metabolites were determined for each subject and correlated with self-report and polysomnographic measures. Results: No statistically significant differences were found between GSC and PI with respect to number of caffeinated beverages consumed (p = 0.91), estimated absolute caffeine ingestion (p = 0.48), time of caffeine consumption (p = 0.22), or plasma concentrations of caffeine (p = 0.92) or paraxanthine (p = 0.88). Significant correlations were found between plasma concentrations of caffeine/paraxanthine and endorsed caffeine intake (r = 0.58, p < 0.05) and estimated absolute caffeine ingestion (r = 0.57, p < 0.05). Plasma caffeine/paraxanthine was significantly correlated with percent stage 1 sleep (r = 0.32, p < 0.05). However, plasma concentrations of caffeine/paraxanthine were not significantly correlated with other subjective or polysomnographic measures of sleep disturbance in either GSC or PI. Conclusions: These data suggest that low-moderate amounts of caffeine consumed in the home environment, and mostly during morning hours, have little effect on subjective or polysomnographic measures of sleep in GSC or PI. Citation: Youngberg MR; Karpov IO; Begley A; Pollock BG; Buysse DJ. Clinical and physiological correlates of caffeine and caffeine metabolites in primary insomnia. J

  10. Caffeine increases light responsiveness of the mouse circadian pacemaker.

    PubMed

    van Diepen, Hester C; Lucassen, Eliane A; Yasenkov, Roman; Groenen, Inske; Ijzerman, Adriaan P; Meijer, Johanna H; Deboer, Tom

    2014-11-01

    Caffeine is the most commonly used psychoactive stimulant worldwide. It reduces sleep and sleepiness by blocking access to the adenosine receptor. The level of adenosine increases during sleep deprivation, and is thought to induce sleepiness and initiate sleep. Light-induced phase shifts of the rest-activity circadian rhythms are mediated by light-responsive neurons of the suprachiasmatic nucleus (SCN) of the hypothalamus, where the circadian clock of mammals resides. Previous studies have shown that sleep deprivation reduces circadian clock phase-shifting capacity and decreases SCN neuronal activity. In addition, application of adenosine agonists and antagonists mimics and blocks, respectively, the effect of sleep deprivation on light-induced phase shifts in behaviour, suggesting a role for adenosine. In the present study, we examined the role of sleep deprivation in and the effect of caffeine on light responsiveness of the SCN. We performed in vivo electrical activity recordings of the SCN in freely moving mice, and showed that the sustained response to light of SCN neuronal activity was attenuated after 6 h of sleep deprivation prior to light exposure. Subsequent intraperitoneal application of caffeine was able to restore the response to light. Finally, we performed behavioural recordings in constant conditions, and found enhanced period lengthening during chronic treatment with caffeine in drinking water in constant light conditions. The data suggest that increased homeostatic sleep pressure changes circadian pacemaker functioning by reducing SCN neuronal responsiveness to light. The electrophysiological and behavioural data together provide evidence that caffeine enhances clock sensitivity to light. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  11. Effect of energy drink and caffeinated beverage consumption on sleep, mood, and performance in children and adolescents.

    PubMed

    Owens, Judith A; Mindell, Jodi; Baylor, Allison

    2014-10-01

    The increasing availability of highly caffeinated beverages, including energy drinks, in the United States has resulted in a rise in consumption by children and adolescents. In addition, there is mounting evidence that these products are often consumed by youth for their perceived fatigue-mitigating and mood- or performance-enhancing effects. Although such perceptions by children and adolescents about the potential consequences of caffeine consumption are highly likely to influence decision making regarding the use of such products, there is still a relative paucity of studies that focus on the effect of caffeinated beverages on sleep, mood, and performance in the pediatric population. This review summarizes the following aspects of this topic, as derived from the information currently available: 1) the perception, among youth, of caffeine's risks and benefits and the sources of information about caffeine, particularly with regard to sleep, mood, and performance; 2) the bidirectional effect of caffeine on sleep in children and adolescents and the association of caffeine with other sleep-related practices, and 3) the evidence that supports caffeine as a performance and mood enhancer as well as a countermeasure to sleepiness in the pediatric population. Finally, gaps in knowledge are identified, and a direction for future research is outlined.

  12. Short-term effect of caffeine on purine, pyrimidine and pyridine metabolism in rice (Oryza sativa) seedlings.

    PubMed

    Deng, Wei-Wei; Katahira, Riko; Ashihara, Hiroshi

    2015-05-01

    As part of our studies on the physiological and ecological function of caffeine, we investigated the effect of exogenously supplied caffeine on purine, pyrimidine and pyridine metabolism in rice seedlings. We examined the effect of 1 mM caffeine on the in situ metabolism of 14C-labelled adenine, guanine, inosine, uridine, uracil, nicotinamide and nicotinic acid. The segments of 4-day-old dark-grown seedlings were incubated with these labelled compounds for 6 h. For purines, the incorporation of radioactivity from [8-(14)C]adenine and [8-(14)C]guanine into nucleotides was enhanced by caffeine; in contrast, incorporation into CO2 were reduced. The radioactivity in ureides (allantoin and allantoic acid) from [8-(14)C]guanine and [8-(14)C]inosine was increased by caffeine. For pyrimidines, caffeine enhanced the incorporation of radioactivity from [2-(14)C]uridine into nucleotides, which was accompanied by a decrease in pyrimidine catabolism. Such difference was not found in the metabolism of [2-(14)C]uracil. Caffeine did not influence the pyridine metabolism of [carbonyl-14C]- nicotinamide and [2-(14)C]nicotinic acid. The possible control steps of caffeine on nucleotide metabolism in rice are discussed.

  13. CaM kinase II and phospholamban contribute to caffeine-induced relaxation of murine gastric fundus smooth muscle.

    PubMed

    Kim, Minkyung; Cho, Sang Yun; Han, In Soo; Koh, Sang Don; Perrino, Brian A

    2005-06-01

    Caffeine has been shown to increase the Ca(2+) release frequency (Ca(2+) sparks) from the sarcoplasmic reticulum (SR) through ryanodine-sensitive stores and relax gastric fundus smooth muscle. Increased Ca(2+) store refilling increases the frequency of Ca(2+) release events and store refilling is enhanced by CaM kinase II (CaMKII) phosphorylation of phospholamban (PLB). These findings suggest that transient, localized Ca(2+) release events from the SR may activate CaMKII and contribute to relaxation by enhancing store refilling due to PLB Thr17 phosphorylation. To investigate this possibility, we examined the effects of caffeine on CaMKII, muscle tone, and PLB phosphorylation in murine gastric fundus smooth muscle. Caffeine (1 mM) hyperpolarized and relaxed murine gastric fundus smooth muscle and activated CaMKII. Ryanodine, tetracaine, or cyclopiazonic acid each prevented CaMKII activation and significantly inhibited caffeine-induced relaxation. The large-conductance Ca(2+)-activated K(+) channel blocker iberiotoxin, but not apamin, partially inhibited caffeine-induced relaxation. Caffeine-induced CaMKII activation increased PLB Thr17, but not PLB Ser16 phosphorylation. 3-Isobutyl-1-methylxanthine increased PLB Ser16 phosphorylation, but not PLB Thr17 phosphorylation. The CaMKII inhibitor KN-93 inhibited caffeine-induced relaxation and PLB Thr17 phosphorylation. These results show that caffeine-induced CaMKII activation and PLB phosphorylation play a role in the relaxation of gastric fundus smooth muscles.

  14. Modification of caffeine-induced injury in Ca2+-free perfused rat hearts. Relationship to the calcium paradox.

    PubMed Central

    Vander Heide, R. S.; Altschuld, R. A.; Lamka, K. G.; Ganote, C. E.

    1986-01-01

    The pathogenesis of the calcium paradox has not been established. In calcium-free perfused hearts, caffeine, which releases calcium from the sarcoplasmic reticulum, causes severe myocardial injury, with creatine kinase (CK) release and contraction band necrosis similar in many respects to the calcium paradox. It has been postulated that contracture, initiated by a small rise in intracellular calcium, may cause sarcolemmal injury in both the calcium paradox and caffeine-induced myocardial injury. The present study was initiated to determine whether interventions which modulate caffeine-induced contracture will also correspondingly alter cellular injury. The effects of caffeine dose, procaine, extended calcium-free perfusion, elevated potassium, temperature, and increasing intracellular sodium on caffeine-induced contracture were examined in Langendorff-perfused adult rat hearts. Caffeine-induced contracture at 22 C increased over a dose range of 5-40 mM caffeine. Procaine, which inhibits caffeine-induced calcium release at doses between 5 and 20 mM, progressively reduced contracture caused by addition of 20 mM caffeine at 22 C. Hearts perfused with calcium-free solution containing 16 mM K+ showed a reduction in caffeine-induced contracture. Extended calcium-free perfusion (20 minutes) at temperatures from 18 to 37 C resulted in a progressive reduction of caffeine-induced contracture. Each of these interventions was also found to inhibit caffeine-induced injury at 37 C. Low temperature was found to have complex effects. Hypothermia enhanced caffeine contractures but also protected hearts from cell separations and CK release. Increasing intracellular sodium was found to enhance caffeine-induced contracture at 37 C. There was a direct correlation between measured intracellular sodium levels and the magnitude and duration of caffeine-induced contracture. These results demonstrate a direct correlation between the magnitude of contracture and myocardial injury in calcium

  15. Caffeine Ingestion Improves Repeated Freestyle Sprints in Elite Male Swimmers

    PubMed Central

    Goods, Paul S.R.; Landers, Grant; Fulton, Sacha

    2017-01-01

    The purpose of this investigation was to determine the efficacy of a moderate dose of caffeine to improve repeat-sprint performance in elite freestyle sprinters. Nine highly trained male swimmers performed 6 x 75 m freestyle sprints on two occasions 1-h after consuming either 3 mg·kg-1 caffeine (CAF), or placebo, in a cross-over manner. Capillary blood samples for the analysis of blood lactate concentration and pH were collected after the 1st, 3rd, and 5th sprint, while heart rate and perceived exertion (RPE) were collected after every sprint. There was a moderate effect for improved mean sprint time in the CAF condition (0.52 s; 1.3%; d = 0.50). When assessed individually, there was a large effect for improved performance in sprints 3 (1.00 s; 2.5%; d = 1.02) and 4 (0.84 s; 2.1%; d = 0.84) in CAF compared to placebo, with worthwhile performance improvement found for each of the first 5 sprints. There was a significant treatment effect for higher blood lactate concentration for CAF (p = 0.029), and a significant treatment*time effect for reduced pH in the CAF condition (p = 0.004). Mean heart rate (167 ± 9 bpm vs 169 ± 7 bpm) and RPE (17 ± 1 vs 17 ± 1) were not different between placebo and CAF trials, respectively. This investigation is the first to demonstrate enhanced repeat-sprint ability in swimmers following acute caffeine ingestion. It appears likely that the combination of a moderate dose of caffeine (3-6 mg·kg-1) with trained athletes is most likely to enhance repeat-sprint ability in various athletic populations; however, the exact mechanism(s) for an improved repeat-sprint ability following acute caffeine ingestion remain unknown. Key points A moderate dose of caffeine (3 mg·kg-1) ingested 1 h before a repeat-sprint freestyle set significantly improves mean sprint time in elite swimmers. The combination of at least a moderate dose of caffeine (>3 mg·kg-1) with trained athletes appears the most likely to result in ergogenic benefit to anaerobic

  16. The Arabidopsis transcription factor NAI1 is required for enhancing the active histone mark but not for removing the repressive mark on PYK10, a seedling-specific gene upon embryonic-to-postgerminative developmental phase transition.

    PubMed

    Yoshii, Masakatsu; Yamamoto, Akiko; Kagaya, Yasuaki; Takeda, Shin; Hattori, Tsukaho

    2015-01-01

    We have recently shown that the expression onset of a seedling-specific gene, PYK10, occurs in a cell-by-cell manner upon the transition from the embryonic to the postgerminative phase and during embryogenesis in seed maturation regulator mutants such as lec1, and implicated epigenetic mechanisms in the process. Here, the role of the NAI1 transcription factor required for PYK10 expression in the developmental switching of PYK10 was investigated. The cell-by-cell onset of PYK10-EGFP in lec1 embryo was still observed in the nai1 background, but at greatly reduced levels. Decreases in the level of the repressive histone mark, H3K27 trimethylation observed upon the transition to the postgeminative phase normally occurred in nai1. However, concomitant increases in the level of the active mark, H3K4 trimethylation observed in wild type was significantly compromised in nai1. These results indicate that the switching of PYK10 upon developmental phase transition involves 2 separable steps of chromatin state change.

  17. Effects of chronic caffeine on adenosine, dopamine and acetylcholine systems in mice.

    PubMed

    Shi, D; Nikodijević, O; Jacobson, K A; Daly, J W

    1994-01-01

    Chronic ingestion of caffeine by male NIH Swiss strain mice leads in about 3 days to a significant increase in A1-adenosine, nicotinic and muscarinic receptors, and a significant decrease of beta 1-adrenoceptors in cerebral cortical membranes. Plasma levels of caffeine in the chronically treated mice range from 0.70 to 5.7 micrograms/ml. The changes in receptors reverse after withdrawal of caffeine within 7 days. An increase in nitrendipine binding sites, associated with L-type calcium channels, also occurs within 4 days and has reversed in 7 days after withdrawal. There is no change in the levels of striatal nicotinic receptors of D2-dopamine receptors, nor of [3H]cocaine binding to dopamine uptake sites. Levels of opioid receptors are either increased (delta) or unaltered (mu, kappa). sigma-Receptors are unaltered. Stimulations of striatal adenylate cyclase by forskolin, dopamine and NECA are not significantly affected after chronic caffeine ingestion. The adenosine agonist, NECA, reverses the amphetamine-elicited increases in locomotor activity and partly reverses the cocaine-elicited increases. The NECA dose-response curve is multiphasic (depression, stimulation and then depression) versus amphetamine in control mice, but only depressant versus amphetamine in chronic caffeine mice, while being multiphasic versus cocaine in both control and chronic caffeine mice. NECA reverses the stimulation of locomotor activity elicited by the muscarinic antagonist, scopolamine, and is more effective in the chronic caffeine mice. The behavioral depressant effects of the muscarinic agonist, oxotremorine, are not markedly altered after chronic caffeine ingestion.

  18. Caffeine as a lipolytic food component increases endurance performance in rats and athletes.

    PubMed

    Ryu, S; Choi, S K; Joung, S S; Suh, H; Cha, Y S; Lee, S; Lim, K

    2001-04-01

    Caffeine is one of the famous ergogenic aids in the athletic field. Caffeine has been known to stimulate lipolysis that spares stored glycogen utilization during moderate intensity exercise. Therefore, we investigated the effects of caffeine ingestion on exercise performance in rats and athletes. Rats were administered the caffeine (6 mg/kg) 1 h prior to the exercise then were run on a treadmill at a speed of 20 m/min. They were decapitated at 0 min, 30 min, 60 min of exercise, and exhausted time point. Human subjects ingested the caffeine (5 mg/kg) 1 h prior to the exercise. They exercised on a cycle ergometer at 60% of their VO2max for 45 min, and then the exercise intensity was increased to 80% of their VO2max until exhaustion. Blood and breathing gas samples were collected and calculated every 10 min during exercise. Respiratory exchange ratio of the caffeine trial was significantly lower than that of the placebo trial in the athletes' study (p<0.05). Blood free fatty acid (FFA) levels in studies of both rats and athletes were increased by caffeine ingestion during exercise (p<0.05). Blood lactate levels were also increased during exercise in both rats and athletes (p<0.05). Increased FFA and glycerol concentrations reduced glycogen utilization during exercise compared with placebo group in rats. In addition, endurance time to exhaustion was significantly increased by the caffeine ingestion in both rats and athletes (p<0.05). These results suggest that the caffeine ingestion enhanced endurance performance resulting from spare stored glycogen with increasing lipolysis from adipose tissues and fat oxidation during exercise both in rats and in athletes.

  19. Muscle Pain as a Regulator of Cycling Intensity: Effect of Caffeine Ingestion.

    PubMed

    Gonglach, Alexander R; Ade, Carl J; Bemben, Michael G; Larson, Rebecca D; Black, Christopher D

    2016-02-01

    Caffeine ingestion improves endurance time trial performance. However, the ergogenic mechanism of action remains unresolved. One potential explanation for caffeine's performance-enhancing effect is an improvement in work for a given amount of muscle pain. To test this hypothesis, participants performed two studies in which they regulated exercise intensity based on feelings of muscle pain. Thirteen young men were asked to regulate exercise intensity based on feelings of "moderate" muscle pain (a "3" on a 0-10 pain scale). After three familiarization trials, either caffeine (∼ 5 mg · kg(-1) body weight) or placebo were administered before a moderate pain trial. Nine caffeine "responders" were retested and ask to regulate their exercise intensity at a "strong" pain level (a "5" on a 0-10 pain scale). A caffeine (∼ 5 mg · kg(-1) body weight) or placebo was again ingested before exercise. Participants performed more work (P = 0.008) and covered more distance (P = 0.008) at a higher average power output (P = 0.009) and VO2 (P = 0.019), for an identical amount of "moderate" muscle pain in the caffeine condition. When exercising at a rating of a "5," caffeine did not increase total work, distance covered, or VO2 for an identical amount of "strong" pain in the nine caffeine "responders." Our findings indicate caffeine increases work performed during exercise, eliciting a moderate amount of a pain. However, a threshold level of muscle pain may exist above which antagonism of adenosine receptors alone does not induce a hypoalgesic effect.

  20. Caffeine Modulates Attention Network Function

    ERIC Educational Resources Information Center

    Brunye, Tad T.; Mahoney, Caroline R.; Lieberman, Harris R.; Taylor, Holly A.

    2010-01-01

    The present work investigated the effects of caffeine (0 mg, 100 mg, 200 mg, 400 mg) on a flanker task designed to test Posner's three visual attention network functions: alerting, orienting, and executive control [Posner, M. I. (2004). "Cognitive neuroscience of attention". New York, NY: Guilford Press]. In a placebo-controlled, double-blind…

  1. Caffeine Use Affects Pregnancy Outcome

    ERIC Educational Resources Information Center

    Diego, Miguel; Field, Tiffany; Hernandez-Reif, Maria; Vera, Yanexy; Gil, Karla; Gonzalez-Garcia, Adolfo

    2008-01-01

    A sample of 750 women were interviewed during pregnancy on their depression and anxiety symptoms, substance use and demographic variables. A subsample was seen again at the neonatal stage (n = 152), and their infants were observed for sleep-wake behavior. Symptoms of depression and anxiety were related to caffeine use. Mothers who consumed more…

  2. Caffeinated beverages and decreased fertility.

    PubMed

    Wilcox, A; Weinberg, C; Baird, D

    104 healthy women who had been attempting to become pregnant for three months were interviewed about their use of caffeinated beverages, alcohol, and cigarettes. In their subsequent cycles, women who consumed more than the equivalent of one cup of coffee per day were half as likely to become pregnant, per cycle, as women who drank less. A dose-response effect was present.

  3. Caffeine Use Affects Pregnancy Outcome

    ERIC Educational Resources Information Center

    Diego, Miguel; Field, Tiffany; Hernandez-Reif, Maria; Vera, Yanexy; Gil, Karla; Gonzalez-Garcia, Adolfo

    2008-01-01

    A sample of 750 women were interviewed during pregnancy on their depression and anxiety symptoms, substance use and demographic variables. A subsample was seen again at the neonatal stage (n = 152), and their infants were observed for sleep-wake behavior. Symptoms of depression and anxiety were related to caffeine use. Mothers who consumed more…

  4. Caffeine Modulates Attention Network Function

    ERIC Educational Resources Information Center

    Brunye, Tad T.; Mahoney, Caroline R.; Lieberman, Harris R.; Taylor, Holly A.

    2010-01-01

    The present work investigated the effects of caffeine (0 mg, 100 mg, 200 mg, 400 mg) on a flanker task designed to test Posner's three visual attention network functions: alerting, orienting, and executive control [Posner, M. I. (2004). "Cognitive neuroscience of attention". New York, NY: Guilford Press]. In a placebo-controlled, double-blind…

  5. NotaMark industrial laser marking system: a new security marking technology

    NASA Astrophysics Data System (ADS)

    Moreau, Vincent G.

    2004-06-01

    Up until now, the only variable alphanumeric data which could be added to banknotes was the number, applied by means of impact typographical numbering boxes. As an additional process or an alternative to this mechanical method, a non-contact laser marking process can be used offering high quality and greater levels of flexibility. For this purpose KBA-GIORI propose an exclusive laser marking solution called NotaMark. The laser marking process NotaMark is the ideal solution for applying variable data and personalizing banknotes (or any other security documents) with a very high resolution, for extremely large production volumes. A completely integrated solution has been developed comprised of laser light sources, marking head units, and covers and extraction systems. NotaMark allows the marking of variable data by removing locally and selectively, specific printed materials leaving the substrate itself untouched. A wide range of materials has already been tested extensively. NotaMark is a new security feature which is easy to identify and difficult to counterfeit, and which complies with the standard mechanical and chemical resistance tests in the security printing industry as well as with other major soiling tests. The laser marking process opens up a whole new range of design possibilities and can be used to create a primary security feature such as numbering, or to enhance the value of existing features.

  6. Caffeine's implications for women's health and survey of obstetrician-gynecologists' caffeine knowledge and assessment practices.

    PubMed

    Anderson, Britta L; Juliano, Laura M; Schulkin, Jay

    2009-09-01

    Caffeine has relevance for women's health and pregnancy, including significant associations with spontaneous abortion and low birth weight. According to scientific data, pregnant women and women of reproductive age should be advised to limit their caffeine consumption. This article reviews the implications of caffeine for women's psychological and physical health, and presents data on obstetrician-gynecologists' (ob-gyns) knowledge and practices pertaining to caffeine. Ob-gyns (N = 386) who are members of the American College of Obstetricians and Gynecologists' Collaborative Ambulatory Research Network responded to a 21-item survey about caffeine. Although most knew that caffeine is passed through breast milk, only 24.8% were aware that caffeine metabolism significantly slows as pregnancy progresses. Many respondents were not aware of the caffeine content of commonly used products, such as espresso and Diet Coke, with 14.3% and 57.8% indicating amounts within an accurate range, respectively. Furthermore, ob-gyns did not take into account large differences in caffeine content across different caffeinated beverages with most recommending one to two servings of coffee or tea or soft drinks per day. There was substantial inconsistency in what was considered to be "high levels" of maternal caffeine consumption, with only 31.6% providing a response. When asked to indicate the risk that high levels of caffeine have on various pregnancy outcomes, responses were not consistent with scientific data. For example, respondents overestimated the relative risk of stillbirths and underestimated the relative risk of spontaneous abortion. There was great variability in assessment and advice practices pertaining to caffeine. More than half advise their pregnant patients to consume caffeine under certain circumstances, most commonly to alleviate headache and caffeine withdrawal. The data suggest that ob-gyns could benefit from information about caffeine and its relevance to their

  7. Consumption of caffeinated beverages and the awareness of their caffeine content among Dutch students.

    PubMed

    Mackus, Marlou; van de Loo, Aurora J A E; Benson, Sarah; Scholey, Andrew; Verster, Joris C

    2016-08-01

    The purpose of the current study was to examine the knowledge of caffeine content of a variety of caffeinated beverages among Dutch university students. A pencil-and-paper survey was conducted among N = 800 Dutch students. Most participants (87.8%) reported consuming caffeinated beverages during the past 24 h. Their mean ± SD past 24-h caffeine intake from beverages was 144.2 ± 169.5 mg (2.2 ± 3.0 mg/kg bw). Most prevalent sources of caffeine were coffee beverages (50.8%) and tea (34.8%), followed by energy drink (9.2%), cola (4.7%), and chocolate milk (0.5%). Participants had poor knowledge on the relative caffeine content of caffeinated beverages. That is, they overestimated the caffeine content of energy drinks and cola, and underestimated the caffeine content of coffee beverages. If caffeine consumption is a concern, it is important to inform consumers about the caffeine content of all caffeine containing beverages, including coffee and tea. The current findings support previous research that the most effective way to reduce caffeine intake is to limit the consumption of coffee beverages and tea. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. A comparison of the effects of caffeine following abstinence and normal caffeine use.

    PubMed

    Addicott, Merideth A; Laurienti, Paul J

    2009-12-01

    Caffeine typically produces positive effects on mood and performance. However, tolerance may develop following habitual use, and abrupt cessation can result in withdrawal symptoms, such as fatigue. This study investigated whether caffeine has a greater stimulant effect in a withdrawn state compared to a normal caffeinated state, among moderate daily caffeine consumers. Using a within-subjects design, 17 caffeine consumers (mean +/- sd = 375 +/- 101 mg/day) ingested placebo or caffeine (250 mg) following 30-h of caffeine abstention or normal dietary caffeine use on four separate days. Self-reported mood and performance on choice reaction time, selective attention, and memory tasks were measured. Caffeine had a greater effect on mood and choice reaction time in the abstained state than in the normal caffeinated state, but caffeine improved selective attention and memory in both states. Although improvements in mood and reaction time may best explained as relief from withdrawal symptoms, other performance measures showed no evidence of withdrawal and were equally sensitive to an acute dose of caffeine in the normal caffeinated state.

  9. Caffeine deprivation state modulates expression of acquired liking for caffeine-paired flavours.

    PubMed

    Chambers, Lucy; Mobini, Sirous; Yeomans, Martin R

    2007-10-01

    Previous studies found that caffeine consumers acquired a liking for the flavour of novel caffeinated drinks when these drinks were consumed repeatedly in a caffeine-deprived, but not nondeprived, state. Expression of this acquired liking appeared acutely sensitive to current caffeine deprivation state, but the use of between-subjects designs confounded interpretation of those studies. The present study evaluated these findings further using a within-subject design, with one flavour paired with caffeine (CS + ) and the second with the absence of caffeine (CS-). During four CS + and four CS- training days, 32 moderate caffeine consumers alternatively consumed a novel flavoured drink a CS + paired with caffeine and a CS- flavour paired with placebo. Participants evaluated both drinks before and after training in two motivational states: caffeine deprived and nondeprived. As predicted, pleasantness ratings for the caffeine-paired flavour increased overall. However, this acquired liking was only significant when tested in a caffeine-deprived state. These data are consistent with a conditioned-flavour preference model and imply that expression of acquired liking for a novel caffeinated flavour depends on the need for the effects of caffeine at the time when the drink is evaluated.

  10. High dose of commercial products of kava (Piper methysticum) markedly enhanced hepatic cytochrome P450 1A1 mRNA expression with liver enlargement in rats.

    PubMed

    Yamazaki, Yuko; Hashida, Hiroko; Arita, Anna; Hamaguchi, Keiko; Shimura, Fumio

    2008-12-01

    Commercial products containing the kava plant (Piper methysticum), known to have the anxiolytic activity, are banned in several European countries and Canada because of the suspicion of a potential liver toxicity. In some reports, kava and kavalactones (major constituents of kava) inhibited activities of cytochrome P450 (CYP) isoforms including CYP1A2. On the other hand, a few studies showed that administration of kava to rats moderately increased CYP1A2 proteins in the liver. CYP1A isoforms are likely responsible for the metabolic activation of potent carcinogenic environmental toxins such as aflatoxins, benzo[a]pyrene, and others. On these bases, we have investigated the effects of administration of commercial kava products on gene expression of hepatic CYP1A isoforms in rats. A high dose (equivalent to approximately 380mg kavalactones/kg/day; 100 times of the suggested dosage for human use) of two different types of kava products for 8 days significantly increased liver weights. CYP1A2 mRNA expression was moderately increased (2.8-7.3 fold). More importantly, the high dose of kava markedly enhanced CYP1A1 mRNA expression (75-220 fold) as well as ethoxyresorufin O-deethylase activities and CYP1A1 immunoreactivities. Thus, no observed adverse effect levels of kavalactones would be lower than 380mg/kg/day. When the safety factor of kavalactones is assumed to be 100, a value most often used upon the risk analysis of chemicals and designed to account for interspecies and intraspecies variations, a number of kava product users likely ingest more kavalactones than acceptable daily intakes. Based on overall evidence, we should pay considerable attention to the possibility that kava products induce hepatic CYP1A1 expression in human especially in sensitive individuals.

  11. Caffeine intake increases plasma ketones: an acute metabolic study in humans.

    PubMed

    Vandenberghe, Camille; St-Pierre, Valérie; Courchesne-Loyer, Alexandre; Hennebelle, Marie; Castellano, Christian-Alexandre; Cunnane, Stephen C

    2017-04-01

    Brain glucose uptake declines during aging and is significantly impaired in Alzheimer's disease. Ketones are the main alternative brain fuel to glucose so they represent a potential approach to compensate for the brain glucose reduction. Caffeine is of interest as a potential ketogenic agent owing to its actions on lipolysis and lipid oxidation but whether it is ketogenic in humans is unknown. This study aimed to evaluate the acute ketogenic effect of 2 doses of caffeine (2.5; 5.0 mg/kg) in 10 healthy adults. Caffeine given at breakfast significantly stimulated ketone production in a dose-dependent manner (+88%; +116%) and also raised plasma free fatty acids. Whether caffeine has long-term ketogenic effects or could enhance the ketogenic effect of medium chain triglycerides remains to be determined.

  12. Sleep-Disordered Breathing and Caffeine Consumption

    PubMed Central

    Aurora, R. Nisha; Crainiceanu, Ciprian; Caffo, Brian

    2012-01-01

    Background: Sleepiness is one of the most burdensome symptoms of sleep-disordered breathing (SDB). While caffeine is frequently used to avert sleepiness, the association between SDB and caffeine use has not been thoroughly explored. The current study examined whether SDB is associated with caffeine consumption and if factors such as sex, age, and daytime sleepiness explain or modify the association. Methods: Data from the Sleep Heart Health Study, a community-based study on the consequences of SDB, were used to characterize the association between SDB and caffeine intake. SDB was assessed with full-montage polysomnography. Caffeine use was quantified as the number of cans of soda or the cups of coffee or tea consumed daily. The Epworth Sleepiness Scale was used to assess daytime sleepiness. Multivariable negative binomial regression models were used to characterize the independent association between SDB and caffeine use. Results: Caffeinated soda, but not tea or coffee, intake was independently associated with SDB severity. Compared with participants without SDB, the relative ratios for caffeinated soda consumption in women with mild, moderate, and severe SDB were 1.20 (CI, 1.03-1.41), 1.46 (CI, 1.14-1.87), and 1.73 (CI, 1.23-2.42), respectively. For men, an association was only noted with severe SDB and caffeinated soda use. Age did not modify the SDB-caffeine association, and sleepiness could not explain the observed associations. Conclusions: SDB is independently associated with caffeinated soda use in the general community. Identifying excessive caffeine used in SDB has potential significance given the cardiovascular effects of caffeine and untreated SDB. PMID:22459776

  13. Recovering Americium and Curium from Mark-42 Target Materials- New Processing Approaches to Enhance Separations and Integrate Waste Stream Disposition - 12228

    SciTech Connect

    Patton, Brad D.; Benker, Dennis; Collins, Emory D.; Mattus, Catherine H.; Robinson, Sharon M.; Wham, Robert M.

    2012-07-01

    Oak Ridge National Laboratory (ORNL) is investigating flowsheets to enhance processing efficiencies and to address waste streams associated with recovery of americium (Am) and curium (Cm) from Mark-42 (Mk-42) target materials stored at ORNL. The objective of this work was to identify the most effective flowsheet with which to process the 104 Mk-42 oxide capsules holding a total of 80 g of plutonium (Pu), 190 g of Cm, 480 g of Am, and 5 kg of lanthanide (Ln) oxides for the recovery and purification of the Am/Cm for future use as feedstock for heavy actinide production. Studies were also conducted to solidify the process flowsheet waste streams for disposal. ORNL is investigating flowsheets to enhance processing efficiencies and address waste streams associated with recovery of Am and Cm from Mk-42 target materials stored at ORNL. A series of small-scale runs are being performed to demonstrate an improved process to recover Am/Cm and to optimize the separations of Ln fission products from the Am/Cm constituents. The first of these runs has been completed using one of the Am/Cm/Ln oxide capsules stored at ORNL. The demonstration run showed promising results with a Ln DF of 40 for the Am/Cm product and an Am/Cm DF of 75 for the Ln product. In addition, the total losses of Am, Cm, and Ln to the waste solvents and raffinates were very low at <0.2%, 0.02%, and 0.04%, respectively. However, the Ln-actinide separation was less than desired. For future Reverse TALSPEAK demonstration runs, several parameters will be adjusted (flow rates, the ratio of scrub to strip stages, etc.) to improve the removal of Ln from the actinides. The next step will also include scale-up of the processing flowsheet to use more concentrated solutions (15 g/L Ln versus 5 g/L) and larger volumes and to recycle the HDEHP solvent. This should improve the overall processing efficiency and further reduce losses to waste streams. Studies have been performed with simulated wastes to develop solidification

  14. The effect of daily caffeine exposure on lever-pressing for sucrose and c-Fos expression in the nucleus accumbens in the rat.

    PubMed

    Retzbach, Edward P; Dholakia, Paulomi H; Duncan-Vaidya, Elizabeth A

    2014-08-01

    Recent reports suggest that caffeine exposure increases the motivation to consume drugs of abuse. As such, it may also enhance the motivation to consume palatable food. Because caffeine is a common constituent in over-the-counter weight-loss supplements, it is important to better understand the relationship between caffeine and food intake. The purpose of this study was to measure the effects of daily intermittent caffeine exposure on lever pressing for sucrose in rats and to assess the impact of caffeine on neuronal activation in the nucleus accumbens (NAc). Male Sprague-Dawley rats that received either saline or caffeine (1, 5, 20mg/kgi.p.) daily were tested on a fixed ratio 4 schedule for sucrose in operant chambers for 10days and then again following a 5-day treatment withdrawal period. After behavioral testing, a subset of the animals was sacrificed to measure the impact of caffeine on neuronal activation in the NAc using c-Fos as a marker. There was a significant increase in active lever presses for sucrose in the rats that had received 5mg/kg of caffeine when compared with the saline group. This treatment effect was no longer present after the withdrawal period. Acute, but not chronic, caffeine exposure elevated c-Fos expression in the NAc. These data suggest that intermittent daily caffeine exposure increases lever pressing for sucrose in rats, but leaves no lasting effect. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. The effect of ephedra and caffeine on maximal strength and power in resistance-trained athletes.

    PubMed

    Williams, Andrew D; Cribb, Paul J; Cooke, Matthew B; Hayes, Alan

    2008-03-01

    Caffeine and ephedrine-related alkaloids recently have been removed from International Olympic Committee banned substances lists, whereas ephedrine itself is now permissible at urinary concentrations less than 10 mug.mL. The changes to the list may contribute to an increased use of caffeine and ephedra as ergogenic aids by athletes. Consequently, we sought to investigate the effects of ingesting caffeine (C) or a combination of ephedra and caffeine (C + E) on muscular strength and anaerobic power using a double-blind, crossover design. Forty-five minutes after ingesting a glucose placebo (P: 300 mg), C (300 mg) or C + E (300 mg + 60 mg), 9 resistance-trained male participants were tested for maximal strength by bench press [BP; 1 repetition maximum (1RM)] and latissimus dorsi pull down (LP; 1RM). Subjects also performed repeated repetitions at 80% of 1RM on both BP and LP until exhaustion. After this test, subjects underwent a 30-second Wingate test to determine peak anaerobic cycling power, mean power, and fatigue index. Although subjects reported increased alertness and enhanced mood after supplementation with caffeine and ephedra, there were no significant differences between any of the treatments in muscle strength, muscle endurance, or peak anaerobic power. Our results do not support the contention that supplementation with ephedra or caffeine will enhance either muscle strength or anaerobic exercise performance.

  16. Alteration of the behavioral effects of nicotine by chronic caffeine exposure.

    PubMed

    Tanda, G; Goldberg, S R

    2000-05-01

    The prevalence of tobacco smoking and coffee drinking place nicotine and caffeine among the most used licit drugs in many societies and their consumption is often characterised by concurrent use. The pharmacological basis for any putative interaction between these drugs remains unclear. Some epidemiological reports support anecdotal evidence, which suggests that smokers consume caffeine to enhance the effects of nicotine. This paper reviews various aspects of the pharmacology of caffeine and nicotine, in humans and experimental animals, important for the understanding of the interactions between these drugs. In particular, recent experiments are reviewed in which chronic exposure to caffeine in the drinking water of rats facilitated acquisition of self-adminstration behavior, enhanced nicotine-induced increases in dopamine levels in the shell of the nucleus accumbens and altered the dopaminergic component of a nicotine discrimination. These studies provide evidence that the rewarding and subjective properties of nicotine can be changed by chronic caffeine exposure and indicate that caffeine exposure may be an important environmental factor in shaping and maintaining tobacco smoking.

  17. Caffeine induces cardiomyocyte hypertrophy via p300 and CaMKII pathways.

    PubMed

    Shi, Liang; Xu, Hao; Wei, Jinhong; Ma, Xingfeng; Zhang, Jianbao

    2014-09-25

    Caffeine is commonly utilized to trigger intracellular calcium in cardiomyocyte. It is well accepted that caffeine could induce cardiac arrhythmia, but it is not clear with regard of its impacts on the cardiac function. This article presents a recent study concerning the effects of caffeine on the cardiomyocyte hypertrophy and the associated signal pathway. The experimental results showed that the total protein contents, the surface area of cardiomyocyte and β-myosin heavy chain (β-MHC) expression increased in ventricular myocytes of neonatal Sprague-Dawley (SD) rats after 24h caffeine incubation. It is also observed that the basal intracellular calcium (Ca(2+)) level has increased, while the amplitude of Ca(2+) oscillation and Ca(2+) content have decreased in sarcoplasmic reticulum (SR). The caffeine-induced myocyte enhancer factor-2 (MEF2) expression and hypertrophy can be completely abolished by the inhibition of cardiac ryanodine receptor (RyR2), as well as KN93 and curcumin treatments. Meanwhile, the amplitude of Ca(2+) oscillation and the Ca(2+) content of SR in the completely-inhibited group have reached the physiological level. These results suggest that the caffeine-induced cardiomyocyte hypertrophy established the connection between Ca(2+) release from SR and cytosol that activates CaMKII and p300, which in turn enhances the expression of MEF2 that promotes cardiomyocyte hypertrophy.

  18. Effect of caffeine contained in a cup of coffee on microvascular function in healthy subjects.

    PubMed

    Noguchi, Katsuhiko; Matsuzaki, Toshihiro; Sakanashi, Mayuko; Hamadate, Naobumi; Uchida, Taro; Kina-Tanada, Mika; Kubota, Haruaki; Nakasone, Junko; Sakanashi, Matao; Ueda, Shinichiro; Masuzaki, Hiroaki; Ishiuchi, Shogo; Ohya, Yusuke; Tsutsui, Masato

    2015-02-01

    Recent epidemiological studies have demonstrated that coffee drinking is associated with reduced mortality of cardiovascular disease. However, its precise mechanisms remain to be clarified. In this study, we examined whether single ingestion of caffeine contained in a cup of coffee improves microvascular function in healthy subjects. A double-blind, placebo-controlled, crossover study was performed in 27 healthy volunteers. A cup of either caffeinated or decaffeinated coffee was drunk by the subjects, and reactive hyperemia of finger blood flow was assessed by laser Doppler flowmetry. In an interval of more than 2 days, the same experimental protocol was repeated with another coffee in a crossover manner. Caffeinated coffee intake slightly but significantly elevated blood pressure and decreased finger blood flow as compared with decaffeinated coffee intake. There was no significant difference in heart rate between caffeinated and decaffeinated coffee intake. Importantly, caffeinated coffee intake significantly enhanced post-occlusive reactive hyperemia of finger blood flow, an index of microvascular endothelial function, compared with decaffeinated coffee intake. These results provide the first evidence that caffeine contained in a cup of coffee enhances microvascular function in healthy individuals. Copyright © 2015 Japanese Pharmacological Society. Production and hosting by Elsevier B.V. All rights reserved.

  19. Insecticidal activity of caffeine aqueous solutions and caffeine oleate emulsions against Drosophila melanogaster and Hypothenemus hampei.

    PubMed

    Araque, Pedronel; Casanova, Herley; Ortiz, Carlos; Henao, Beatriz; Pelaez, Carlos

    2007-08-22

    The bioactivity of caffeine aqueous solutions (0.20-2.00 wt %) and caffeine oleate emulsions (20 vol % oil, 2.00 wt % surfactant, 0.04 wt % caffeine, 0.05 wt % oleic acid) was assessed against two biological models: Drosophila melanogaster and Hypothenemus hampei. The caffeine aqueous solutions showed no insecticidal activity, whereas caffeine oleate emulsions had high bioactivity against both D. melanogaster and H. hampei. By preparing the caffeine oleate emulsions with anionic surfactants (i.e., sodium lauryl sulfate, sodium laureate, and sodium oleate), we obtained a lethal time 50 (LT50) of 23 min. In the case of caffeine oleate emulsions prepared with nonionic surfactants (i.e., Tween 20 and Tween 80), a LT50 of approximately 17 min was observed. The high bioactivity of the caffeine oleate emulsion against H. hampei opens the possibility of using this insecticide formulation as an effective way to control this pest that greatly affects coffee plantations around the world.

  20. Acute effects of caffeine on heart rate variability in habitual caffeine consumers.

    PubMed

    Rauh, Robert; Burkert, Michaela; Siepmann, Martin; Mueck-Weymann, Michael

    2006-05-01

    During the last years, heart rate variability (HRV) has become a promising risk factor for cardiovascular events. However, the effect of caffeine on HRV in habitual caffeine consumers has barely been investigated. Therefore, we treated 30 male habitual caffeine users in a randomized double-blinded crossover study design with either placebo, 100 or 200 mg caffeine orally and determined parameters of HRV under resting conditions and metronomic breathing. As result, we could not detect significant differences in HRV parameters up to 90 min after drug ingestion. We conclude that modest amounts of caffeine do not reveal negative nor positive effects on HRV within the first 90 min after drug ingestion in young and healthy habitual caffeine consumers. However, further research is necessary to determine the effects of caffeine on HRV in habitual caffeine users, healthy as well as suffering from diabetes, hypertension and postmyocardial infarction.

  1. Caffeine extends life span, improves healthspan, and delays age-associated pathology in Caenorhabditis elegans

    PubMed Central

    2012-01-01

    impact of caffeine on a worm model of polyglutamine disease suggests that chronic caffeine consumption may generally enhance resistance to proteotoxic stress and may be relevant to assessing risk and developing treatments for human diseases like Alzheimer’s and Huntington’s disease. Future work addressing the relevant targets of caffeine in models of aging and healthspan will help to clarify the underlying mechanisms and potentially identify new molecular targets for disease intervention. PMID:24764514

  2. A case of atrial tachycardia sensitive to increased caffeine intake.

    PubMed

    Kinugawa, Toru; Kurita, Takashi; Nohara, Ryuji; Smith, Michael L

    2011-01-01

    A 33-year-old Japanese man with atrial tachycardia visited our clinic. He regularly consumed daily alcohol with cola, one cup of regular coffee, and a candy containing 0.7 mg of caffeine per tablet. After stopping his caffeine intake, his arrhythmia ameliorated. Since caffeine might be associated with his arrhythmia, a caffeine load test (equivalent to his daily intake of caffeine) was performed for 4 days. Atrial tachycardia time from a Holter recording was 44.2 minute/day before the caffeine load, compared with 215.2 minute/day during the caffeine load. Plasma caffeine concentration before and during caffeine loading was 3.1 mg/dL and 5.4 mg/dL, respectively. Caffeine use seemed to be an important factor for his atrial tachycardia, since his arrhythmia became worse during caffeine load testing and was ameliorated after the cessation of caffeine.

  3. The effect of a caffeinated mouth-rinse on endurance cycling time-trial performance.

    PubMed

    Doering, Thomas M; Fell, James W; Leveritt, Michael D; Desbrow, Ben; Shing, Cecilia M

    2014-02-01

    The purpose of this study was to investigate if acute caffeine exposure via mouth-rinse improved endurance cycling time-trial performance in well-trained cyclists. It was hypothesized that caffeine exposure at the mouth would enhance endurance cycling time-trial performance. Ten well-trained male cyclists (mean ± SD: 32.9 ± 7.5 years, 74.7 ± 5.3 kg, 176.8 ± 5.1cm, VO₂peak = 59.8 ± 3.5 ml·kg⁻¹·min⁻¹) completed two experimental time-trials following 24 hr of dietary and exercise standardization. A randomized, double-blind, placebo-controlled, cross-over design was employed whereby cyclists completed a time-trial in the fastest time possible, which was equivalent work to cycling at 75% of peak aerobic power output for 60 min. Cyclists were administered 25 ml mouth-rinses for 10 s containing either placebo or 35 mg of anhydrous caffeine eight times throughout the time-trial. Perceptual and physiological variables were recorded throughout. No significant improvement in time-trial performance was observed with caffeine (3918 ± 243 s) compared with placebo mouth-rinse (3940 ± 227 s). No elevation in plasma caffeine was detected due to the mouth-rinse conditions. Caffeine mouth-rinse had no significant effect on rating of perceived exertion, heart rate, rate of oxygen consumption or blood lactate concentration. Eight exposures of a 35 mg dose of caffeine at the buccal cavity for 10s does not significantly enhance endurance cycling time-trial performance, nor does it elevate plasma caffeine concentration.

  4. Effects of caffeine and carbohydrate mouth rinses on repeated sprint performance.

    PubMed

    Beaven, C Martyn; Maulder, Peter; Pooley, Adrian; Kilduff, Liam; Cook, Christian

    2013-06-01

    Our purpose was to examine the effectiveness of carbohydrate and caffeine mouth rinses in enhancing repeated sprint ability. Previously, studies have shown that a carbohydrate mouth rinse (without ingestion) has beneficial effects on endurance performance that are related to changes in brain activity. Caffeine ingestion has also demonstrated positive effects on sprint performance. However, the effects of carbohydrate or caffeine mouth rinses on intermittent sprints have not been examined previously. Twelve males performed 5 × 6-s sprints interspersed with 24 s of active recovery on a cycle ergometer. Twenty-five milliliters of either a noncaloric placebo, a 6% glucose, or a 1.2% caffeine solution was rinsed in the mouth for 5 s prior to each sprint in a double-blinded and balanced cross-over design. Postexercise maximal heart rate and perceived exertion were recorded, along with power measures. A second experiment compared a combined caffeine-carbohydrate rinse with carbohydrate only. Compared with the placebo mouth rinse, carbohydrate substantially increased peak power in sprint 1 (22.1 ± 19.5 W; Cohen's effect size (ES), 0.81), and both caffeine (26.9 ± 26.9 W; ES, 0.71) and carbohydrate (39.1 ± 25.8 W; ES, 1.08) improved mean power in sprint 1. Experiment 2 demonstrated that a combination of caffeine and carbohydrate improved sprint 1 power production compared with carbohydrate alone (36.0 ± 37.3 W; ES, 0.81). We conclude that carbohydrate and (or) caffeine mouth rinses may rapidly enhance power production, which could have benefits for specific short sprint exercise performance. The ability of a mouth-rinse intervention to rapidly improve maximal exercise performance in the absence of fatigue suggests a central mechanism.

  5. Caffeine dose-dependently induces thermogenesis but restores ATP in HepG2 cells in culture.

    PubMed

    Riedel, Annett; Pignitter, Marc; Hochkogler, Christina M; Rohm, Barbara; Walker, Jessica; Bytof, Gerhard; Lantz, Ingo; Somoza, Veronika

    2012-09-01

    Caffeine has been hypothesised as a thermogenic agent that might help to maintain a healthy body weight. Since very little is known about its actions on cellular energy metabolism, we investigated the effect of caffeine on mitochondrial oxidative phosphorylation, cellular energy supply and thermogenesis in HepG2 cells, and studied its action on fatty acid uptake and lipid accumulation in 3T3-L1 adipocytes at concentrations ranging from 30-1500 μM. In HepG2 cells, caffeine induced a depolarisation of the inner mitochondrial membrane, a feature of mitochondrial thermogenesis, both directly and after 24 h incubation. Increased concentrations of uncoupling protein-2 (UCP-2) also indicated a thermogenic activity of caffeine. Energy generating pathways, such as mitochondrial respiration, fatty acid oxidation and anaerobic lactate production, were attenuated by caffeine treatment. Nevertheless, HepG2 cells demonstrated a higher energy charge potential after exposure to caffeine that might result from energy restoration through attenuation of energy consuming pathways, as typically found in hibernating animals. In 3T3-L1 cells, in contrast, caffeine increased fatty acid uptake, but did not affect lipid accumulation. We provide evidence that caffeine stimulates thermogenesis but concomitantly causes energy restoration that may compensate enhanced energy expenditure.

  6. Caffeine (1, 3, 7-trimethylxanthine) in foods: a comprehensive review on consumption, functionality, safety, and regulatory matters.

    PubMed

    Heckman, Melanie A; Weil, Jorge; Gonzalez de Mejia, Elvira

    2010-04-01

    Caffeine ranks as one of the top most commonly consumed dietary ingredients throughout the world. It is naturally found in coffee beans, cacao beans, kola nuts, guarana berries, and tea leaves including yerba mate. The total daily intake, as well as the major source of caffeine varies globally; however, coffee and tea are the 2 most prominent sources. Soft drinks are also a common source of caffeine as well as energy drinks, a category of functional beverages. Moderate caffeine consumption is considered safe and its use as a food ingredient has been approved, within certain limits, by numerous regulatory agencies around the world. Performance benefits attributed to caffeine include physical endurance, reduction of fatigue, and enhancing mental alertness and concentration. Caffeine has also been recently linked to weight loss and consequent reduction of the overall risks for developing the metabolic syndrome. However, the caloric contribution of caffeine-sweetened beverages needs to be considered in the overall energy balance. Despite all these benefits the potential negative effects of excessive caffeine intake should also be considered, particularly in children and pregnant women.

  7. Effects of nicotine and caffeine, separately and in combination, on EEG topography, mood, heart rate, cortisol, and vigilance.

    PubMed

    Gilbert, D G; Dibb, W D; Plath, L C; Hiyane, S G

    2000-09-01

    Effects of nicotine and caffeine, separately and in combination, were assessed in 12 male habitual smokers in a repeated-measures design. Caffeine (0-mg vs. two 150-mg doses administered in a decaffeinated/sugar-free cola drink post-baseline and 90 min later) was crossed with nicotine (ad libitum own dosing vs. 1.0-mg machine-delivered dose vs. 0.05-mg machine-delivered dose). Participants smoked a total of five cigarettes at 30-min intervals over a 2-hr period. Caffeine and nicotine had large effect sizes on electroencephalogram (EEG) power; however, these effects were modulated by the eyes open versus closed condition, the other drug, and electrode site. EEG effects of open versus closed eyes tended to be of the same size and direction as those of nicotine and caffeine. However, whereas nicotine increased EEG power in some higher frequency bands in some conditions, caffeine decreased EEG power across almost all conditions. Serum cortisol concentration, vigor, and pleasantness were increased by nicotine, but not by caffeine. Level of depressive mood depended on an interaction of caffeine and nicotine. Vigilance performance was enhanced significantly by caffeine and was increased almost significantly by nicotine. The findings were interpreted in terms of common and differential mechanisms of the two drugs.

  8. Clinical and physiological correlates of caffeine and caffeine metabolites in primary insomnia.

    PubMed

    Youngberg, Mark R; Karpov, Irina O; Begley, Amy; Pollock, Bruce G; Buysse, Daniel J

    2011-04-15

    To explore the relationship between plasma concentrations of caffeine and subjective and polysomnographic measures of sleep in both good sleeper controls (GSC) and individuals with primary insomnia (PI), following the consumption of low-moderate quantities of caffeine in the home environment. 65 PI and 29 GSC, each consuming < 4 four coffee cup equivalents of caffeine daily, were recruited. Subjects completed a diary detailing sleep habits and caffeine consumption, one night of polysomnography, and a blood sample for measurement of plasma caffeine and its metabolites at bedtime. Plasma concentrations of caffeine, its primary metabolite, paraxanthine, and other metabolites were determined for each subject and correlated with self-report and polysomnographic measures. No statistically significant differences were found between GSC and PI with respect to number of caffeinated beverages consumed (p = 0.91), estimated absolute caffeine ingestion (p = 0.48), time of caffeine consumption (p = 0.22), or plasma concentrations of caffeine (p = 0.92) or paraxanthine (p = 0.88). Significant correlations were found between plasma concentrations of caffeine/paraxanthine and endorsed caffeine intake (r = 0.58, p < 0.05) and estimated absolute caffeine ingestion (r = 0.57, p < 0.05). Plasma caffeine/paraxanthine was significantly correlated with percent stage 1 sleep (r = 0.32, p < 0.05). However, plasma concentrations of caffeine/paraxanthine were not significantly correlated with other subjective or polysomnographic measures of sleep disturbance in either GSC or PI. These data suggest that low-moderate amounts of caffeine consumed in the home environment, and mostly during morning hours, have little effect on subjective or polysomnographic measures of sleep in GSC or PI.

  9. Imaging caffeine-induced Ca2+ transients in individual fast-twitch and slow-twitch rat skeletal muscle fibers.

    PubMed

    Pagala, M K; Taylor, S R

    1998-03-01

    Fast-twitch and slow-twitch rat skeletal muscles produce dissimilar contractures with caffeine. We used digital imaging microscopy to monitor Ca2+ (with fluo 3-acetoxymethyl ester) and sarcomere motion in intact, unrestrained rat muscle fibers to study this difference. Changes in Ca2+ in individual fibers were markedly different from average responses of a population. All fibers showed discrete, nonpropagated, local Ca2+ transients occurring randomly in spots about one sarcomere apart. Caffeine increased local Ca2+ transients and sarcomere motion initially at 4 mM in soleus and 8 mM in extensor digitorum longus (EDL; approximately 23 degrees C). Ca2+ release subsequently adapted or inactivated; this was surmounted by higher doses. Motion also adapted but was not surmounted. Prolonged exposure to caffeine evidently suppressed myofilament interaction in both types of fiber. In EDL fibers, 16 mM caffeine moderately increased local Ca2+ transients. In soleus fibers, 16 mM caffeine greatly increased Ca2+ release and produced propagated waves of Ca2+ (approximately 1.5-2.5 microns/s). Ca2+ waves in slow-twitch fibers reflect the caffeine-sensitive mechanism of Ca2(+)-induced Ca2+ release. Fast-twitch fibers possibly lack this mechanism, which could account for their lower sensitivity to caffeine.

  10. Caffeine sensitivity of native RyR channels from normal and malignant hyperthermic pigs: effects of a DHPR II-III loop peptide.

    PubMed

    Gallant, Esther M; Hart, James; Eager, Kevin; Curtis, Suzanne; Dulhunty, Angela F

    2004-04-01

    Enhanced sensitivity to caffeine is part of the standard tests for susceptibility to malignant hyperthermia (MH) in humans and pigs. The caffeine sensitivity of skeletal muscle contraction and Ca(2+) release from the sarcoplasmic reticulum is enhanced, but surprisingly, the caffeine sensitivity of purified porcine ryanodine receptor Ca(2+)-release channels (RyRs) is not affected by the MH mutation (Arg(615)Cys). In contrast, we show here that native malignant hyperthermic pig RyRs (incorporated into lipid bilayers with RyR-associated lipids and proteins) were activated by caffeine at 100- to 1000-fold lower concentrations than native normal pig RyRs. In addition, the results show that the mutant ryanodine receptor channels were less sensitive to high-affinity activation by a peptide (C(S)) that corresponds to a part of the II-III loop of the skeletal dihydropyridine receptor (DHPR). Furthermore, subactivating concentrations of peptide C(S) enhanced the response of normal pig and rabbit RyRs to caffeine. In contrast, the caffeine sensitivity of MH RyRs was not enhanced by the peptide. These novel results showed that in MH-susceptible pig muscles 1). the caffeine sensitivity of native RyRs was enhanced, 2). the sensitivity of RyRs to a skeletal II-III loop peptide was depressed, and 3). an interaction between the caffeine and peptide C(S) activation mechanisms seen in normal RyRs was lost.

  11. Evaluating the Validity of Caffeine Use Disorder.

    PubMed

    Budney, Alan J; Lee, Dustin C; Juliano, Laura M

    2015-09-01

    Caffeine use disorder is included in the conditions for further study section of the DSM-5. Caffeine's profile of neurobiological, behavioral, and clinical effects is similar to other common substances that humans use recreationally. Extant data suggest that a clinically meaningful addictive disorder develops in some regular caffeine users, but this literature is incomplete and not yet sufficient to determine if and how best to define and treat caffeine use disorder. An overview of the literature relevant to determining the clinical importance of problematic caffeine use is followed by discussion of potential concerns and benefits associated with its classification as a mental disorder. Concerns about overdiagnosis and trivialization of other psychiatric syndromes are weighed against the public health benefits of increased awareness and development of interventions targeting problematic caffeine use. This discussion includes consideration of alternative diagnostic approaches, improvement of assessment practices, and the need for additional clinical and epidemiological research.

  12. Caffeine deprivation state modulates coffee consumption but not attentional bias for caffeine-related stimuli.

    PubMed

    Stafford, L D; Yeomans, M R

    2005-11-01

    Previous research has shown that caffeine deprivation state can exert a strong influence on the ability of caffeine to reinforce behaviour. Recent work has also found evidence for an attentional bias in habitual caffeine users. It remains unclear whether deprivation state can influence attentional bias. Here we explored the relationship between caffeine deprivation, attentional bias to caffeine-related stimuli and subsequent caffeine reinforcement measured by consumption of coffee. In three experiments, participants (between-subjects: n=28; within-subjects: n=20, within-subjects: n=20) were preloaded with either caffeine (experiments 1 and 3 : 100 mg; experiment 2 : 150 mg) or placebo, and in experiments 1 and 2 they completed a novel attentional bias task involving pre-attentive word recognition, and in experiment 3 a dot-probe task. In experiments 2 and 3, this was followed by a test of coffee consumption. Greater recognition for caffeine-related words (experiments 1 and 2) and faster reaction times to probes replacing caffeine-related rather than control stimuli (experiment 3) confirmed caffeine-related attentional biases, but in no case was this affected by manipulation of caffeine-deprivation state. Participants in a deprived versus nondeprived state, however, experienced increases in drowsiness and headaches (experiment 2) and reduced alertness (experiment 3). Further, coffee consumption was greatest when participants were caffeine-deprived than when they were nondeprived. Findings are discussed in relation to prevailing theories of drug addiction.

  13. Caffeine choice prospectively predicts positive subjective effects of caffeine and d-amphetamine

    PubMed Central

    Sigmon, Stacey C.; Griffiths, Roland R.

    2011-01-01

    Background Individuals vary in their subjective and behavioral response to psychomotor stimulants and these differences may be associated with the likelihood of developing problematic use of these drugs. The present study sought to determine whether individual differences in caffeine choice prospectively predict subjective response to acute doses of caffeine and d-amphetamine. Methods In Phase 1, Choosers and Nonchoosers of caffeine were identified using 10 independent choice trials in which subjects repeatedly chose between caffeine (200 mg/70kg) or placebo. Choosers were defined as those who chose caffeine over placebo on ≥ 7 of the 10 trials; Nonchoosers were those who chose placebo on ≥ 7 trials. In Phase 2, Choosers and Nonchoosers were compared in their subjective response to caffeine (100, 200, 400 mg/70kg) and d-amphetamine (5, 10, 20 mg/70kg). Results Of the 22 participants completing the study, 11 met criteria for being a caffeine Chooser and 8 were Nonchoosers. In Phase 1, Choosers reported higher ratings of positive (i.e., pleasant) and lower ratings of negative (i.e., unpleasant) effects of caffeine during the sampling sessions. In Phase 2, caffeine Choosers reported more positive subjective effects and fewer negative effects of caffeine and d-amphetamine, particularly at the highest doses examined. Conclusions Individual differences in caffeine reinforcement predicted subsequent subjective response to both d-amphetamine and caffeine. This observation may have clinical utility for identifying individuals who are vulnerable to the reinforcing effects of abused psychomotor stimulants. PMID:21600707

  14. Caffeine: how much is too much?

    PubMed

    McKim, E M; McKim, W A

    1993-12-01

    Too much caffeine can cause numerous physical and psychological symptoms of poor health. It could negatively affect reproduction and is suspected of causing some cancers. It can affect cardiovascular functioning, and can even produce symptoms similar to those of mental illness. Despite this broad range of known and suspected effects of caffeine, nurses rarely consider caffeine intake in initial nursing assessments of clients. They should.

  15. Role of adenosine receptors in caffeine tolerance

    SciTech Connect

    Holtzman, S.G.; Mante, S.; Minneman, K.P. )

    1991-01-01

    Caffeine is a competitive antagonist at adenosine receptors. Receptor up-regulation during chronic drug treatment has been proposed to be the mechanism of tolerance to the behavioral stimulant effects of caffeine. This study reassessed the role of adenosine receptors in caffeine tolerance. Separate groups of rats were given scheduled access to drinking bottles containing plain tap water or a 0.1% solution of caffeine. Daily drug intake averaged 60-75 mg/kg and resulted in complete tolerance to caffeine-induced stimulation of locomotor activity, which could not be surmounted by increasing the dose of caffeine. 5'-N-ethylcarboxamidoadenosine (0.001-1.0 mg/kg) dose dependently decreased the locomotor activity of caffeine-tolerant rats and their water-treated controls but was 8-fold more potent in the latter group. Caffeine (1.0-10 mg/kg) injected concurrently with 5-N-ethylcarboxamidoadenosine antagonized the decreases in locomotor activity comparably in both groups. Apparent pA2 values for tolerant and control rats also were comparable: 5.05 and 5.11. Thus, the adenosine-antagonist activity of caffeine was undiminished in tolerant rats. The effects of chronic caffeine administration on parameters of adenosine receptor binding and function were measured in cerebral cortex. There were no differences between brain tissue from control and caffeine-treated rats in number and affinity of adenosine binding sites or in receptor-mediated increases (A2 adenosine receptor) and decreases (A1 adenosine receptor) in cAMP accumulation. These results are consistent with theoretical arguments that changes in receptor density should not affect the potency of a competitive antagonist. Experimental evidence and theoretical considerations indicate that up-regulation of adenosine receptors is not the mechanism of tolerance to caffeine-induced stimulation of locomotor activity.

  16. Caffeine synthase and related methyltransferases in plants.

    PubMed

    Misako, Kato; Kouichi, Mizuno

    2004-05-01

    Caffeine (1,3,7-trimethylxanthine) is a purine alkaloid present in high concentrations in tea and coffee and it is also found in a number of beverages such as coca cola. It is necessary to elucidate the caffeine biosynthetic pathway and to clone the genes related to the production of caffeine not only to determine the metabolism of the purine alkaloid but also to control the content of caffeine in tea and coffee. The available data support the operation of a xanthosine-->7-methylxanthosine-->7-methylxanthine-->theobromine-->caffeine pathway as the major route to caffeine. Since the caffeine biosynthetic pathway contains three S-adenosyl-L-methionine (SAM) dependent methylation steps, N-methyltransferases play important roles. This review focuses on the enzymes and genes involved in the methylation of purine ring. Caffeine synthase, the SAM-dependent methyltransferase involved in the last two steps of caffeine biosynthesis, was originally purified from young tea leaves (Camellia sinensis). The isolated cDNA, term