Evidence against the involvement of a noradrenergic mechanism in the release by diazepam of novelty-induced hypophagia in rats.
The involvement of noradrenergic processes in both the behavioral suppression and release of food intake induced by diazepam, was investigated using the novelty-induced inhibition of food consumption model. Clonidine (7.5-60 micrograms/kg i.p.) and another alpha 2-noradrenergic receptor agonist, guanfacine (0.25-1 mg/kg i.p.), increased the food intake of rats placed in an unfamiliar situation. The effects of clonidine (15 micrograms/kg) were antagonized by yohimbine (0.5-2 mg/kg i.p.). Clonidine (7.5 micrograms/kg) was unable to enhance the efficacy of diazepam (0.5 and 1 mg/kg i.p.) in stimulating food consumption, whereas yohimbine (0.5-2 mg/kg) did not reduce and even increased the potency of diazepam (2 mg/kg) to facilitate food intake. These findings suggest that although noradrenergic processes (and in particular alpha 2-adrenoreceptors) are involved in the hyponeophagia model they do not mediate the releasing effect exerted by benzodiazepines on novelty-induced suppression of food intake.
D000818:Animals; D001007:Anxiety / Q000187:drug effects; D003000:Clonidine / Q000494:pharmacology; D003975:Diazepam / Q000494:pharmacology*; D004347:Drug Interactions; D004435:Eating / Q000187:drug effects*; D016316:Guanfacine; D006146:Guanidines / Q000494:pharmacology; D006801:Humans; D008297:Male; D051379:Mice; D009638:Norepinephrine / Q000502:physiology*; D010648:Phenylacetates / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011941:Receptors, Adrenergic / Q000187:drug effects; D015016:Yohimbine / Q000494:pharmacology
D006146:Guanidines; D010648:Phenylacetates; D011941:Receptors, Adrenergic; D015016:Yohimbine; D016316:Guanfacine; D003000:Clonidine; D003975:Diazepam; D009638:Norepinephrine