Stimulants, caffeine

The nucleophilicity of the nitrogen atom survives in many different functional groups, although its basicity may be lost. Reactions of non-basic, but nucleophilic urea nitrogens provide, for example, an easy entry to sleeping-pills (barbiturates) as well as to stimulants (caffeine). The nitrogen atoms of imidazoles and indole anions are also nucleophilic and the NH protons can be easily substituted. 

Caffeine is a mild to potent CNS stimulant, with the degree of its stimulating effect dependent on the dose administered. Caffeine stimulates the CNS at all levels, including the cerebral cortex, die medulla, and the spinal cord. Caffeine has mild analeptic (respiratory stimulating) activity. Other actions include cardiac stimulation (which may produce tachycardia), dilatation of coronary and peripheral blood vessels, constriction of cerebral blood vessels, and skeletal muscle stimulation. Caffeine also has mild diuretic activity. 

Avoid alcohol and stimulants (caffeine, nicotine) in the late afternoon and evening. 

In their study of untrained vs. trained swimmers, Collomp et al.40 suggested that specific training may be the catalyst that stimulates caffeine s ergogenic effects during high intensity, anaerobic activity. The results of many studies have also suggested that only well-trained athletes derive significant benefits from caffeine due to the athletes previously stimulated lipolytic activity and the increased size and density of their mito-chondria.40-52-58-59... 

We continue our theme of coffee . Most coffees contain a large amount of the heterocyclic stimulant caffeine (I). Some people prefer to decrease the amounts of caffeine they ingest for health reasons, or they simply do not like to consume it at all, and they ask for decaffeinated coffee instead. 

Intracellular messengers A biphasic effect of ginkgo extract is seen on cAMP phosphodiesterase under in vitro and ex vivo conditions (Saponara and Bosisio 1998 Macovschi et al. 1987). Whereas low concentrations (0.25-4.0 mg/L) activate the enzyme, higher concentrations (5-250 mg/L), dose-dependently inhibit it. However, tolerance develops to this effect because it is undetectable after daily administration for 4 days. Thus, ginkgo may initially produce effects by inhibiting enzymatic breakdown of cAMP. This mechanism is similar to the stimulant caffeine, but it is not likely to explain any long-term effects of ginkgo because it disappears after chronic daily treatment. The responsible constituent for this effect has not been identified. 

The drinking of tea had provided the main stimulant (caffeine) in the Far East for over 4000 years. Another source of caffeine, coffee, has a much shorter, but equally interesting and important history. 

In addition to being a stimulant, caffeine also has many effects outside of the nervous system. Caffeine is a cardiovascular stimulant, causing the heart rate to increase while constricting blood vessels, both of which can cause increases in blood pressure. Caffeine is also a diuretic (i.e., it increases urination), so it can sometimes cause dehydration and low calcium levels. If taken during pregnancy, the amount of caffeine should be limited to 300 mg per day, as birth problems have been reported in pregnant women who consume more than this amount. 

C hocolate3 has been the savior of many a student on the long night before a major assignment was due. My favorite chocolate bar, jammed with 33% fat and 47% sugar, propels me over mountains in California s Sierra Nevada In addition to its high energy content, chocolate packs an extra punch with the stimulant caffeine and its biochemical precursor, theobromine. 

The reticular formation is also located in the midbrain and brainstem. The reticular formation is comprised of a collection of neurons that extend from the reticular substance of the upper spinal cord through the midbrain and the thalamus. The reticular formation monitors and controls consciousness and is also important in regulating the amount of arousal or alertness in the cerebral cortex. Consequently, CNS drugs that affect the arousal state of the individual tend to exert their effects on the reticular formation. Sedative-hypnotics and general anesthetics tend to decrease activity in the reticular formation, whereas certain CNS stimulants (caffeine, amphetamines) may increase arousal through a stimulatory effect on reticular formation neurons. 

Metabolic processes speed up appreciably under the influence of caffeine. Fatty acids are released into the blood, and a general increase in metabolism is evident as there is increased muscle activity, raised temperature, or both. More calcium is made available through caffeine s action in the muscles for contraction, but this effect is evident only at caffeine doses higher than people commonly use. Gut motility and secretion increase with a release of stomach acid and digestive enzymes. Urination is also stimulated caffeine directly affects the kidneys, cutting into their ability to reabsorb electrolytes and water. For every cup of coffee or two to three cans of caffeinated soft drink consumed, about 5 mg of calcium is lost in the urine. 

In addition to cocaine, there are numerous other plant stimulants. Caffeine and nicotine are probably the best known of these naturally occurring substances some of these naturally occurring substances are discussed in chapter 7. 

An important natural product for most of us is a fully methylated purine present in tea and coffee— caffeine. Theobromine, the partly methylated version, is present in chocolate, and both caffeine and theobromine act as stimulants. Caffeine is a crystalline substance easily extracted from coffee or tea with organic solvents. It is extracted industrially with liquid CO2 (or if you prefer Nature s natural effervescence ) to make decaffeinated tea and coffee. 

Methylxanthine is the major purine constituent of human urine (3.1 g in 1000 L). 3- and 7-Methylpurines are also minor constituents of urine, especially following large doses of caffeine or other methylated xanthines. 1,3-Dimethylxanthine (theophylline) occurs with caffeine in tea leaves and is a powerful diuretic. It has been used clinically in the treatment of asthma. The main purine constituent of the cocoa bean is 3,7-dimethylxanthine (theobromine). 1,2,7-Trimethylxanthine (caffeine) is the major purine of the coffee bean and also occurs in tea leaves (3.5%). It acts as a cardiac and respiratory stimulant. Caffeine can be extracted from the natural source by extraction with hot water. ... 

Tea and coffee have been popular beverages for centuries, primmly because they contain the stimulant caffeine. It stimulates respiration, the heart, and the central nervous system, and is a diuretic (promotes urination). It can cause nervousness and insomnia and, like many drugs, can be addictive, making it difficult to reduce the daily dose. A regulcu coffee drinker who consumes as few as four cups per day can experience headache, insomnia, and even nausea upon withdrawal from the drug. 

Ginseng ASA, NSAIDs Antidiabetic agents Clopidogrel, ticlopidine CNS stimulants, caffeine Corticosteroids Digoxin MAO inhibitors Warfarin Additive antiplatelet effects Additive hypoglycemia Additive antiplatelet effects Additive CNS toxicity Additive CNS toxicity Falsely elevated levels Increased toxicity Increased risk of bleeding... 

Ma huang CNS stimulants, caffeine Digoxin MAO inhibitors Additive CNS stimulation Additive toxicity Hypertensive crisis... 

Several OTC analgesic preparations contain caffeine, the rationale being that as a central nervous system stimulant caffeine will alleviate the depression often associated with pain. 

One is contained in all the cups of tea, coffee, and cocoa which we consume. All of these beverages contain the stimulant caffeine. Whenever you take a cup of coffee, you are a drug user. We could go further. Whenever you crave a cup of coffee, you are a drug addict. Even kids are not immune. They get their caffeine shot from coke or pepsi. Whether you like it or not, caffeine is a drug. When you take it, you experience a change of mood or feeling. 

Other key derivatives, xanthine (2,6-dihydroxypurine, 4) and hypoxanthine (6-hydroxypurine, 5), are formed by the hydrolytic decomposition of nucleic acids. As their systematic names indicate, the well-known CNS stimulants caffeine (1,3,7-trimethylxanthine, 6), theophylline (1,3-dimethylxanthine), and theobromine (3,7-dimethyl-xanthine), found in coffee, tea, and cocoa beans, respectively, are all derived from xanthine. 

Sinus tachycardia Increased SA automaticity results in a sinus rhythm in excess of 100 beats per minute. Sinus tachycardia is usually not pathological and is caused by simple anxiety or stimulants (caffeine, amphetamines). 

These ayahuasca cohorts are known stimulants, used alone and as ayahuasca additives. In the latter case, their function appears to be counteracting the marked soporific effects of ayahuasca, so shaman or patient will not fall asleep during the session. Both Ilexguayusa and PauUiniayoco are known to be abundant sources of the stimulant caffeine (Lewis et al. 1991 Schultes 1986A Schultes Raffauf 1990), and Erythroxlum coca vat. ipadii is a known source of the stimulant cocaine (Holmstedt etal. 1971 Plowman 1981),... 

Additive sympathetic stimulation (caffeine, ephedra, green tea, guarana)... 

Stimulant caffeine (I) and their metabolites, theophylline (H) and theobromine (IE)... 

Plant-derived alkaloids are widely used in many purposes that include analgesics (morphine and codeine), stimulants (caffeine and nicotine), anticancer agents (vincristine, vinblastine, and camptothecin derivatives), gout suppressant (colchicine), muscle relaxant (C-tubocurarine, antiarrhythmic ajmaline), antibiotic (sanguinarine), and sedative (scopolamine) [1]. So, different biotechnological approaches are undertaken for the large-scale production of these compounds. 

Other common alkaloids include caffeine and nicotine, both of which are stimulants. Caffeine is found in the coffee bean, and nicotine is found in tobacco. Although both have some addictive qualities, nicotine is by far the most addictive. A nicotine addiction is among the most difficult to break, as any smoker can attest. 

Uses of HPLC include analysis of oil alcoholic beverages antioxidants, sugars and vitamins in foods pharmaceuticals polymers biochemical and biotechnology research presence of the stimulant caffeine in competing athletes and quality control of insecticides and herbicides. 

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