Determination of Adenosine Receptor-G Protein Coupling: Significance for Psychiatric and Neurological Disorders

The purine nucleoside adenosine has been shown to act as a neuromodulator in many areas of the mammalian brain. One of the main actions of adenosine in the central nervous system is the modulation of the release of a variety of neurotransmitters. Adenosine acts as a general depressant in the brain. In contrast, adenosine receptor antagonists show somnolytic and stimulant properties. Although purinergic psychopharmaceuticals are rare, the nonselective adenosine receptor antagonist caffeine may currently be considered the most frequently used nonprescription drug (Fredholm, 1995 ). Caffeine is of therapeutical benefit in states of migraine headache and headache of nonvascular origin. It is used as an adjuvant in analgesic medications, for the treatment of idiopathic apnea in premature neonates, and for seizure prolongation during courses of electroconvulsive therapy for the treatment of depression (Sawynok, 1995 ).