Caffeine의 체내 대사기전과 행동적 영향에 대한 고찰

Effects of Caffeine on Mentabolic Mechanism and Behavior

  Caffeine, which is present with other methylxanthines in such common foods as coffees, teas, and cola beverages, is one of the most widely consumed pharmacologically active substances. In addition, caffeine is used in a variety of analgesic, appetite suppresant, and central stimulant preparations. It can have stimulant effects on the central nervous, cardiovascular, and renal systems. These effects include more rapid and clear flow of thought, increased capacity for intellectual work, less drowsiness, small increases in heart rate, and polyuria.   Caffeine is moderately soluble is water, yet sufficiently hydrophobic to traverse biological membranes with ease. It is rapidly and completely absorbed from the gastrointestinal tract after oral consumption. Once absorbed, caffeine is widely distributed in the body by passive diffusion.   The molecular mechanisms of the behavioral actions of caffeine has not been fully elucidated. It is known that caffeine can either inhibit AMP phosphodiesterase, thus preventing the inactivation of cyclic AMP or block adenosine receptor activity. The latter hypothesis that the physiologically most important molecular action for caffeine involves competitive antagonism at extracellular adenosine receptors has been accepted more reasonable.   Behavioral effects of dietary caffeine as ordinarily taken are slight and unobtrusive. Also, what is toxic and what is not, what is sought after and what is unwanted side effect, depends on circumstances. A reduction in sleepiness with consequent improved performance and efficiency with caffeine may be a desired effect by a worker in the middle of the day, but a toxic effect to an agitated insomniac in the middle of the night.   The evidence available provides ample assurance that sane dietary intakes of caffeine have no substantial deleterious effects on health. Reports of serious bad effects have consistently failed to be sustained by careful further examination. Advances In biotechnology will make the behavioral studies more conceivable and feasible.