7-methylinosine and deoxyinosine

The purines inosine and hypoxanthine have been implicated in neurobiological effects associated with benzodiazepine-receptor occupancy, and may be endogenous ligands of benzodiazepin receptors. The behavioral effects of purinergic activation upon anxious behaviors have been less well characterized and understood. We present evidence that purinergic stimulation is sufficient to produce an operationally defined conditioned anxiety response, and that the effect is specific to the benzodiazepine receptor. These findings suggest anxiogenic potency for purines, which may be associated with their normal behavioral and motivational mode of action.

Topics: Animals; Arousal; Chlorides; Conditioning, Psychological; Dose-Response Relationship, Drug; Fear; Inosine; Lithium; Lithium Chloride; Oxazepam; Rats; Rats, Inbred Strains; Receptors, Cell Surface; Receptors, GABA-A

Inosine peripherally administered to rats markedly suppressed spontaneous food intake and food intake induced by diazepam, muscimol, insulin, and food deprivation. The purines 2-deoxyguanosine and 2-deoxyinosine also suppressed food deprivation-induced feeding, whereas 7-methylinosine, which does not bind to the benzodiazepine binding site in vitro, had no effect on food intake when compared with controls. These results suggest that purines may represent endogenous substances that regulate food intake through interactions with the benzodiazepine receptor.

Topics: Animals; Appetite; Deoxyguanosine; Diazepam; Eating; Food Deprivation; Inosine; Insulin; Male; Muscimol; Purines; Rats; Rats, Inbred Strains; Structure-Activity Relationship