Caffeine central nervous system effects

The various stimulants have no obvious chemical relationships and do not share primary neurochemical effects, despite their similar behavioral effects. Cocaines chemical strucmre does not resemble that of caffeine, nicotine, or amphetamine. Cocaine binds to the dopamine reuptake transporter in the central nervous system, effectively inhibiting dopamine reuptake. It has similar effects on the transporters that mediate norepinephrine and serotonin reuptake. As discussed later in this chapter in the section on neurochemical actions mediating stimulant reward, dopamine is very important in the reward system of the brain the increase of dopamine associated with use of cocaine probably accounts for the high dependence potential of the drug. 

Yu G, Maskray V, Jackson SH, Swift CG, Tiplady B. (1991). A comparison of the central nervous system effects of caffeine and theophylline in elderly subjects. BrJ Clin Pharmacol. 32(3) 341-45. Zelger JL, Carlini EA. (1980). Anorexigenic effects of two amines obtained from Catha edulis Forsk. (Khat) in rats. Pharmacol Biochem Behav. 12(5) 701-5. 

The adverse effects of caffeine are a common experience to most caffeine consumers. Too much caffeine results in uncomfortable to adverse central nervous system effects, or neurotoxicity. The effects include restlessness, tension, and mild tremor or the jitters and may progress to feelings of anxiety and even fear. Regular caffeine users soon learn how to manage their caffeine consumption to maintain blood caffeine at a desirable level that produces mild stimulation without the uncomfortable neurotoxic effects. Fortunately, the half-life of caffeine is short, so that any undesirable effects soon decline. Many people also experience insomnia from caffeine consumption. Caffeine s effect on sleep varies from individual to individual. Some people can consume caffeine late in the evening and sleep well, but for other people consumption of caffeine late in the day affects sleep. It is important to understand your own individual response to caffeine. 

The methylxanthines have effects on the central nervous system, kidney, and cardiac and skeletal muscle as well as smooth muscle. Of the three agents, theophylline is most selective in its smooth muscle effects, whereas caffeine has the most marked central nervous system effects. 

Because of the central nervous system effects from caffeine, many people prefer decaffeinated coffee. The caffeine is removed from coffee by extrachng the whole beans with an organic solvent. Then the solvent is drained off, and the beans are steamed to remove any residual solvent. The beans are dried and roasted to bring out the flavor. Decaffeination reduces the caffeine content of coffee to the range of 0.03% to 1.2%. The extracted caffeine is used in various pharmaceutical products, such as APC tablets. 

C7H9N402- M.p. 337 C, an alkaloid obtained from cacao seeds or prepared synthetically. Constitutionally it is similar to caffeine, and is also a weak base. It is usually administered as the sodium compound combined with either sodium ethanoate or sodium salicylate, and is employed almost entirely as a diuretic. Physiologically theobromine resembles caffeine, but its effect on the central nervous system is less, while its action on the kidneys, is more pronounced. 

AH three of these materials are apparentiy central nervous system (CNS) stimulants. It is beheved that for most individuals caffeine causes greater stimulation than does theophylline. Theobromine apparentiy causes the least stimulation. There is some evidence that caffeine acts on the cortex and reduces drowsiness and fatigue, although habituation can reduce these effects. 

Caffeine is considered by pharmacologists to be a mild stimulant of the central nervous system. It has been shown to promote feelings of well being and increased abiUty to perform certain mental tasks efficiently. There are people who are oversensitive to the effects of caffeine overindulgence by these individuals, eg, intake of more than 600 mg caffeine/d, can bring unwanted effects such as anxiety, restlessness, sleeping difficulties, headache, or palpitations of the heart (54). 

The most promising mechanism of action, which may account for some of caffeine s potential ergogenic effects, involves its demonstrated ability as a competitive antagonist of the depressant effects of adenosine analogs in the central nervous system. Adenosine and its derivatives have been shown to inhibit neuronal electrical activity, the release of neurotransmitters, and to interfere with synaptic transmission.19-24 27... 

Caffeine is also effective in the antagonism of peripheral adenosine (type I) receptors, which are known to inhibit lipolysis by subduing adenylate cyclase activity.28 The appeal of this mechanism of action is that the majority of the pharmacological effects of adenosine on the central nervous system can be inhibited by doses of caffeine that are well within physiologically non-toxic levels comparable to only a couple of cups of coffee.5... 

Although research has been suggestive of caffeine modulated increases in muscular contractions leading to hand tremor, it is more likely that the hand tremor response is the result of caffeine s effects on the central nervous system.32 There is even evidence that moderate doses of caffeine may actually diminish muscle tone.32... 

Nehlig, A., Daval, J. L., and Debry, G., Caffeine and the central nervous system Mechanisms of action, biochemical, metabolic, and psychostimulant effects, Brain Research Reviews, 17, 139, 1992. 

Azcona, O., Barbanoj, M. J., Torrent, J., and Jane, F., Evaluation of the effects of alcohol-caffeine interaction on the central nervous system. Journal of Psychopharmacology 6, 136, 1992. 

Virus, R. M., Ticho, S., Pilditch, M. Radulovacki, M. (1990). A comparison of the effects of caffeine, 8-cyclopentyltheophylline, and alloxazine on sleep in rats. Possible roles of central nervous system adenosine receptors. Neuropsychopharmacology 3 (4), 243-9. 

Caffeine is a powerful stimulant of central nervous system and also stimulates the cardiac muscle. However, high amounts of the alkaloid have noticeable irritation of gastrointestinal tract as well causes matw unwanted effects [1]. 

Substance-Induced Anxiety Disorder. Numerous medicines and drugs of abuse can produce panic attacks. Panic attacks can be triggered by central nervous system stimulants such as cocaine, methamphetamine, caffeine, over-the-counter herbal stimulants such as ephedra, or any of the medications commonly used to treat narcolepsy and ADHD, including psychostimulants and modafinil. Thyroid supplementation with thyroxine (Synthroid) or triiodothyronine (Cytomel) can rarely produce panic attacks. Abrupt withdrawal from central nervous system depressants such as alcohol, barbiturates, and benzodiazepines can cause panic attacks as well. This can be especially problematic with short-acting benzodiazepines such as alprazolam (Xanax), which is an effective treatment for panic disorder but which has been associated with between dose withdrawal symptoms. 

These compounds competitively inhibit phosphodiesterase, resulting in an increase in cyclic AMP (see Box 14.3) and subsequent release of adrenaline. This leads to the major effects a stimulation of the central nervous system (CNS), a relaxation of bronchial smooth muscle, and induction of diuresis. These effects vary in the three compounds. Caffeine is the best CNS stimulant, and has weak diuretic action. Theobromine has little stimulant action, but has more diuretic activity and also muscle relaxant properties. Theophylline also has low stimulant action and is an effective diuretic, but it relaxes smooth muscle better than caffeine or theobromine. 

Caffeine and the related dimethylxanthines have similar pharmacological or therapeutic effects and similar toxic effects. The primary actions include stimulation of the central nervous system, relaxation of bronchial muscles, mild cardiac muscle stimulation, and diuretic effects on the kidney. 

Thea assamica Mast T. bohea L. T. cantoniensis Lour. T. chinensis Sims. T. cochinchinensis Lour. T. sinensis L. T. viridis Link. Cha (Tea) (leaf) Caffeine, theophylline, tannic acid, theobromine, xanthine, polyphenols. 33-47.405,406,409 Diuretic effect, increase renal blood flow, stimulate central nervous system, antitumor, prevent lung cancer. 

Camellia sinensis (L.) Kuntze China Caffeine, theophylline, tannic acid, theobromine, xanthine.33,47 Diuretic effect, increases renal blood flow, stimulate central nervous system. 

Benefits The caffeine content makes guarana a strong central nervous system stimulant. It is traditionally used as a tonic for fatigue and to allay hunger and thirst. It also has short-term diuretic effects. The tannin content gives guarana an astringent effect and it has been used to treat diarrhoea. 

Caffeine, by blocking the action of the body s adenosine, affects a wide variety of organs, as well as the brain, the gut, and basic metabolism. Theophylline works more actively on respiration and the heart. Caffeine is more active in the gut and in the central nervous system. Theobromine has very weak, if any, effect on the brain, but it retains the methylxanthine effect on the kidneys, increasing urination. 

Ephedra supplements typically contain caffeine, and users may consume caffeine in carbonated beverages, coffee, or tea. Researchers suspect that caffeine may enhance ephedra s stimulant effects on cardiovascular and/or central nervous system responses. This may account for the types of adverse events that have been reported by ephedra users. 

The modes of action of different alkaloids are diverse. For example, nicotine binds to and affects nicotinic acetylcholine receptors and shows toxicity. A recent molecular 3D model suggests that both acetylcholine and nicotine bind to the same pocket formed in a nicotinic acetylcholine receptor.15 Morphine binds to and activates opioid receptors, transmembrane-spanning G protein-coupled receptors, in the central nervous system of humans.16 Caffeine, which is structurally similar to adenine, inhibits cyclic AMP phosphodiesterase activity and inhibits the degradation of cAMP, thus exerting a toxic effect on insects 17 in human beings, binding of caffeine to the adenosine A2A receptor induces wakefulness.18 Atropine binds to muscarinic acetylcholine receptors, competing with acetylcholine, and blocks neurotransmission.1... 

Sleep. Caffeine affects sleep of older more than it does of younger people and this may be related to the fact that older people show greater catecholamine turnover in the central nervous system than do the young. Onset of sleep (sleep latency) is delayed, bodily movements are increased, total sleep time is reduced, there are increased awakenings. Tolerance to this effect does not occur, as is shown by the provision of decaffeinated coffee. ... 

Many drugs used for recreational as well as medical purposes can stimulate the central nervous system and so are referred to as stimulants. We separate. stimulants into tsvo groups according to their legal and social status. Controlled stimulants such as cocaine, amphetamines, methylphenidate (Ritalin), and related compounds are treated in this chapter, and over-the-counter stimulants such as nicotine and caffeine are dealt with in Chapters 7 and 8. We first consider the hi.story of stimulant use and discuss some of the effects of cocaine and the amphetamines as we review their history. Then we turn to a more detailed treatment of the pharmacology of these stimulants. 

The main ingredient in OTC stimulants is caffeine. Plienylpropanolamine (Pl A) was a common ingredient in such preparations until 2000, when tlie FDA withdrew OTC approval because it was found to increase the risk of stroke. Popular brands of OTC stimulants are No-Doz and Vivarin. They certainly will induce mild central nervous system stimulation, but No-Doz, for example, contains about as much caffeine as one or two cups of coffee, so the user should expect about that effect. Information on the side effects of caffeine was presented in C hapter 8. 

Systemically it is a stimulant to all parts of the central nervous system including the brain, the spinal cord, and the medulla. Its effects upon the brain are shown by an exaltation of the intellectual faculties similar to that which is produced by caffeine. In overdose it produces a delirium somewhat suggesting that of atropine, to which it is chemically related Its action upon the spinal cord is shown by increased activity of the reflexes but the convulsions which are seen in cocaine poisoning both in the lower animals and in man seem to be due to an action upon... 

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