Potential Sites Of Action

Three major mechanisms must be considered with respect to the actions of caffeine on the peripheral and central nervous system (1) blockade of adenosine receptors, in particular Ar and A2A-adenosine receptors (2) blockade of phosphodiesterases, regulating levels of cyclic nucleotides and (3) action on ion channels, in particular those regulating intracellular levels of calcium and those regulated by the inhibitory neurotransmitters g-aminobutyric acid (GABA) and glycine (Fredholm, 1980 Daly,...

Introduction

Because of its presence in popular drinks, caffeine is doubtlessly the most widely consumed of all behaviorally active drugs Serafin, 1996 Fredholm et al., 1999 . Although caffeine is the major pharmacologically active methylxanthine in coffee and tea, cocoa and chocolate contain severalfold higher levels of theobromine than caffeine, along with trace amounts of theophylline. Paraxanthine is a major metabolite of caffeine in humans, while theophylline is a minor metabolite. Thus, not only...

References

Abernathy, D.R., Todd, E.L. and Schwartz, J.B. 1985 Caffeine disposition in obesity. British Journal of Clinical Pharmacology, 20, 61-66. Akerstedt, T. and Ficca, G. 1997 Alertness-enhancing drugs as a countermeasure to fatigue in irregular work hours. Chronobiology International, 14, 145-158. Alford, C., Bhatti, J., Leigh, T., Jamnieson, A. and Hindmarch, I. 1996 Caffeine-induced sleep disruption effects on waking the following day and its reversal with an hypnotic. Human Psychopharmacology,...