Microinjections of methyl-beta-carboline-3-carboxylate into the dorsal raphe nucleus: behavioural consequences.
Very small quantities (0.01-10 ng) of the inverse benzodiazepine receptor agonist, methyl-beta-carboline-3-carboxylate (beta-CCM) microinjected into the dorsal raphe nucleus (DRN) of the rat selectively reduced social interaction, an effect consistent with an increase in anxiety. Similarly, intraperitoneally injected beta-CCM, within a limited dose range, reduced social interaction without affecting locomotor activity. The benzodiazepine receptor antagonist, RO15-1788 (1 ng) microinjected into the DRN, reversed the suppression of social interaction induced by either intra-raphe or intraperitoneal beta-CCM. Histological examination of the beta-CCM microinjection sites showed that locations within the DRN were almost invariably associated with decreases in social interaction; microinjections failing to decrease social interaction were located primarily outside the DRN. We conclude that the DRN has a major role in expressing the anxiogenic effect of beta-CCM and it may therefore be an important area in the neuronal system controlling anxiety.
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D002243:Carbolines / Q000008:administration & dosage / Q000494:pharmacology*; D005106:Exploratory Behavior / Q000187:drug effects; D007267:Injections; D007274:Injections, Intraperitoneal; D008297:Male; D008845:Microinjections; D011903:Raphe Nuclei; D051381:Rats; D011919:Rats, Inbred Strains; D012919:Social Behavior
D002243:Carbolines; C026072:1-methyl-beta-carboline-3-carboxylic acid