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Caffeine and the central nervous system: Mechanisms of action, biochemical, metabolic and psychostimulant effects

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Abstract

Caffeine is the most widely consumed centralnervous-system stimulant. Three main mechanisms of action of caffeine on the central nervous system have been described. Mobilization of intracellular calcium and inhibition of specific phosphodiesterases only occur at high non-physiological concentrations of caffeine. The only likely mechanism of action of the methylxanthine is the antagonism at the level of adenosine receptors. Caffeine increases energy metabolism throughout the brain but decreases at the same time cerebral blood flow, inducing a relative brain hypoperfusion. Caffeine activates noradrenaline neurons and seems to affect the local release of dopamine. Many of the alerting effects of caffeine may be related to the action of the methylxanthine on serotonine neurons. The methylxanthine induces dose-response increases in locomotor activity in animals. Its psychostimulant action on man is, however, often subtle and not very easy to detect. The effects of caffeine on learning, memory, performance and coordination are rather related to the methylxanthine action on arousal, vigilance and fatigue. Caffeine exerts obvious effects on anxiety and sleep which vary according to individual sensitivity to the methylxanthine. However, children in general do not appear more sensitive to methylxanthine effects than adults. The central nervous system does not seem to develop a great tolerance to the effects of caffeine although dependence and withdrawal symptoms are reported.
... Estudos realizados nas últimas décadas mostraram associação entre o consumo de café com a quimioproteção contra diferentes tipos de doenças crônicas, incluindo o câncer (Crippa et al., 2014;Vitaglione;Fogliano;Pellegrini, 2012), doenças cardiovasculares (Crippa et al., 2014), Parkinson e Alzheimer (Nehlig;Daval;Debry, 2015 ...
... Estudos realizados nas últimas décadas mostraram associação entre o consumo de café com a quimioproteção contra diferentes tipos de doenças crônicas, incluindo o câncer (Crippa et al., 2014;Vitaglione;Fogliano;Pellegrini, 2012), doenças cardiovasculares (Crippa et al., 2014), Parkinson e Alzheimer (Nehlig;Daval;Debry, 2015 ...
Article
Este artigo de revisão narrativa aborda o impacto do consumo de café e seus constituintes sobre a microbiota intestinal. A microbiota é uma comunidade de microrganismos que desempenham papéis essenciais na saúde do hospedeiro, influenciando o sistema imunológico, digestão e até funções neurológicas. Estudos sugerem que compostos presentes no café, como cafeína e ácidos clorogênicos, podem modificar a composição da microbiota intestinal, promovendo o crescimento de bactérias benéficas e inibindo a proliferação de patógenos. A revisão explorou artigos publicados entre 2000 e 2022, encontrados nas bases de dados SciELO, PubMed e MEDLINE, utilizando descritores como "café", "constituintes do café" e "microbiota intestinal". Os resultados apontam para uma relação entre o consumo de café e a melhora na composição da microbiota, com possíveis efeitos protetores contra doenças crônicas como diabetes tipo 2, obesidade e doenças cardiovasculares. Embora os mecanismos exatos ainda não estejam totalmente compreendidos, a cafeína e os compostos fenólicos parecem desempenhar um papel importante na modulação da microbiota intestinal, contribuindo para a manutenção da saúde gastrointestinal. Palavras-chave: Microbiota intestinal. Consumo de café. Cafeína. Compostos fenólicos
... Energy drinks are reported to contain as much as 80 -300mg of caffeine and 35g 0f processed sugar per 8 -OZ serving ( Clauson et al ., 2008). In human caffeine acts as a central nervous system stimulant, hence it is used both recreationally and medically to reduce physical fatigue and restore mental alertness when unusual weakness or drowsiness occurs (Nehlig et al., 1992;Maidon et al., 2012). ...
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Caffeine is a most common ingredient in energy and cola drinks. Due to its stimulating effect and possibly health risk, it is important to ascertain how much of it is in these drinks. This study was carried out to determine the amount of caffeine in four brands of energy(Ed) and cola drinks (Cd), commonly consumed in Rufus Giwa Polytechnic.Owo,Ondo State, Nigeria.Quantitative analysis of caffeine was performed by a simple and fast spectrophotometric method using carbon tetrachloride as the extracting solvent. The result showed that brand 1Cd(27.70±0.04mg/L) has the lowest level of caffeine content while brand 2Ed (60.36±0.06) has the highest caffeine content. The caffeine content of all the drink samples analysedin the study were well below the maximum allowable limit set by FDA.
... Runge demonstrated the ability of coffee to enhance alertness and cognitive function (Runge, 1820). In the early 1990s, scientists confirmed three main mechanisms underlying the psychostimulant properties of caffeine: adenosine receptor antagonism, mobilization of intracellular calcium, and phosphodiesterase inhibition (Ferré et al., 1991;Fiani et al., 2021;Nehlig et al., 1992). ...
Chapter
Coffee consumption has become a daily ritual for a significant portion of the global population, primarily due to its ability to alleviate tiredness, enhance alertness, and improve concentration. The effects of coffee on the human body, particularly the nervous system, have been a longstanding inquiry within the field of neuroscience. This chapter aims to provide a comprehensive overview of the scientific community’s efforts in understanding the positive and negative effects of coffee consumption on the central nervous system, with a focus on quantifiable changes observed in electroencephalography recordings. By examining the electrical behavior of brain signals, this research sheds light on the neurophysiological impact of caffeine, uncovering valuable insights into its influence on brain activity. These findings contribute to a deeper understanding of the intricate relationship between coffee consumption and the central nervous system, paving the way for future investigations and potential therapeutic applications.
... Caffeine is a central nervous system stimulant that antagonizes adenosine receptors and is legal globally [112]. Caffeine consumption has often been documented as an analgesic adjuvant. ...
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Opioids are commonly used to reduce pain after surgery; however, there are severe side effects and complications associated with opioid use, with addiction being of particular concern. Recent practice has shifted to reduce opioid consumption in surgery, although a specific protocol for rhinoplasty is still in progress. This paper aims to expand on the protocol previously established by the senior author based on updated evidence and details. This was accomplished by first high-lighting and summarizing analgesic agents with known opioid-reducing effects in the surgical field, with a particular focus on rhinoplasty, then compiling these analgesic options into a recommended protocol based on the most effective timing of administration (preoperative, intraoperative, postoperative). The senior author’s previous article on the subject was referenced to compile a list of analgesic agents of importance. Each analgesic agent was then searched in PubMed in conjunction with “rhinoplasty” or “opioid sparing” to find relevant primary sources and systematic reviews. The preferred analgesic agents included, as follows: preoperative, 1000 mg oral acetaminophen, 200 mg of oral celecoxib twice daily for 5 days, and 1200 mg oral gabapentin; intraoperative, 0.75 μg/kg of intravenous dexmedetomidine and 1–2 mg/kg injected lidocaine with additional 2–4 mg/kg per hour or 1.5 cc total bupivacaine nerve block injected along the infraorbital area bilaterally and in the subnasal region; and postoperatively, 5 mg oral acetaminophen and 400 mg of oral celecoxib. When choosing specific analgesic agents, considerations include potential side effects, contraindications, and the drug-specific mode of administration.
... In view of the exceptional distinct properties of graphene oxide and SnTe, it is expected to have excellent performance when these two are combined. In addition, by tuning the chemical stoichiometry of in a loss of bone mass and also it may induce cardiovascular diseases [30]. Subsequently, when researchers conducted studies on the composition of breast milk after the mother has taken coffee or any caffeinated drink, it was estimated that 5% of the caffeine in the beverage being consumed by the mother is passed on to the infant through the breast milk [31]. ...
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In this investigation, a rapid microwave-assisted method was employed for the first time to synthesize the GO/SnTe nanocomposite. This approach lowers the energy barrier and accelerates the reaction, significantly impacting the shape and activity of the GO/SnTe nanocomposite. Tin telluride is a desirable electroactive component because of its low bandgap and high theoretical capacity. Additionally, the high surface area and defective structure of GO promote enhanced current flow across the electrode. The integration of these two materials generates a synergistic effect, enhancing electrocatalytic activity for the efficient oxidation of caffeine. Furthermore, the fabricated GO/SnTe-GC electrode outperformed reported electrodes for caffeine oxidation, exhibiting a broad linear range of 4.1–255 µM and a detection limit of 1.56 μM. On the other hand, the findings from real sample analysis and anti-interference studies indicate that this innovative material holds promise for developing novel electrochemical sensors. Particularly, graphene oxide modified with tin chalcogenides act as a real-time sensor with specific applications to real samples such as human milk and drug formulations.
... 13 Caffeine is a widely consumed psychoactive substance known for its stimulatory effects on the central nervous system. 28 Note: Data are presented as mean ± standard deviation or proportion of patients with the outcome (%). Bold font means p-value is less than 0.05 (Statistical significant). ...
Article
Background Fasting headaches frequently occur during the first few days of Ramadan, and treatment is challenging because of fasting. Objective This study aimed to evaluate the effect of extended‐release paracetamol on preventing fasting headaches. Methods A randomized, open‐label clinical trial investigated the efficacy of extended‐release paracetamol at a daily dose of 1330 mg in preventing fasting headache. Adults aged 18 years and older were recruited through the Clinical Trial Unit at the King Saud University Medical City. The eligible participants in the study fasted 13.5 h daily during the first week of Ramadan. Participants in the treatment and control arms were followed up to investigate the occurrence, severity, and timing of headache symptoms via self‐reporting using a standardized headache diary scale with a daily online link or phone call. The primary outcome was the frequency of headache episodes while fasting during the first week of Ramadan. Results A total of 238 participants were enrolled and randomized. Of these, 173 followed the protocol (80 treated, 93 control) for at least the first day and were included in the analysis. Most participants were young and healthy, with a mean age of 32.2 ± 10.2 years. More men were included in the study (102/173; 59.0%), a small proportion of participants were smokers (31/173; 17.9%), and almost all participants reported being coffee drinkers (165/173; 95.4%); nonetheless, these characteristics were evenly distributed between the two groups in the study. The overall incidence of headache episodes was 33.0% (57/173) on day 1 and decreased to 11.3% (18/159) on day 7. On average over the 7 days, no significant effect was observed for the treatment on the incidence of headache, as the findings from the generalized estimating equation model indicated ( β = −0.398, p = 0.084; odds ratio = 0.67, 95% confidence interval [CI] 0.42–1.06). Moreover, there was initially no significant difference in the incidence of headache episodes between the treatment and control groups. However, the treatment group had significantly fewer headache episodes during fasting than the control group on day 3 (4/72 [5.6%] vs. 15/91 [16.5%], p = 0.031; relative risk [RR] = 0.34, 95% CI 0.12–0.97) and day 6 (5/69 [7.2%] vs. 20/90 [22.2%], p = 0.010; RR = 0.33, 95% CI 0.13–0.82). No adverse effects were observed during the study period. Conclusion No significant differences were observed in the occurrence of fasting headaches between the two groups on most days during the study period. Additional studies are required to address fasting headaches during the first week of Ramadan.
... Orally administered caffeine rapidly crosses the blood-brain barrier, inducing a mild stimulant effect. 71 This increase in behavioral arousal can be prevented by other adenosine antagonists such are 7-MX or topically instilled caffeine. 8,9 Future studies are required to determine compounds and doses that allow to sufficiently stimulate the dopaminergic activity of the retina without causing undesirable effects, mainly in children who are the targeted population for myopia control. ...
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Purpose: To determine the acute effect of caffeine intake on the retinal responses as measured with a global-flash multifocal electroretinogram (gfmERG) protocol at different contrast levels. Methods: Twenty-four young adults (age = 23.3 ± 2.4 years) participated in this placebo-controlled, double-masked, balanced crossover study. On two different days, participants orally ingested caffeine (300 mg) or placebo, and retinal responses were recorded 90 minutes later using a gfmERG at three contrast levels (95%, 50%, and 29%). The amplitude response density and peak time of the direct and induced components (direct component [DC] and induced component [IC], respectively) were extracted for five different eccentricities (1.3°, 5.0°, 9.6°, 15.2°, and 21.9°). Axial length, spherical equivalent refraction, habitual caffeine intake, and body weight were considered as continuous covariates. Results: Increased IC amplitude response density was found after caffeine ingestion in comparison to placebo (P = 0.021, ƞp2 = 0.23), specifically for the 95% and 50% stimulus contrasts (P = 0.024 and 0.018, respectively). This effect of caffeine on IC amplitude response density was independent of the retinal eccentricity (P = 0.556). Caffeine had no effect on DC amplitude response density or DC and IC peak times. Conclusions: Our results show that oral caffeine intake increases the inner electro-retinal activity in young adults when viewing stimuli of high- (95%) to medium-contrast (50%). Given the increasing evidence that the inner retinal function is involved in the emmetropization process, these results may suggest that caffeine or its derivatives could potentially play a role in the mechanisms involved in eye growth.
... Caffeine is one of the most consumed stimulants in the world. 117 The correlation between caffeine consumption and a lower risk of developing PD is still controversial and beyond the scope of this review. 118 However, one crossover, double-blinded and randomized study demonstrated that caffeine has the potential to shorten the latency to the levodopa response, assessed by walking and tapping speed, and to increase the walking magnitude. ...
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