title: Desipramine induces yawning behaviour in rats.
abstract: Yawning behaviour in rats injected subcutaneously with antidepressant drugs was studied by direct observation. Desipramine (0.1-30 mg/kg) elicited yawning that began 15-20 min after injection and lasted for 60 min, and the dose-response curve showed a bell-shaped form. Desipramine (10 mg/kg) elicited the maximal effect (mean number of yawns 13.6). Haloperidol (0.02 mg/kg), spiperone (0.2 mg/kg), pimozide (4 mg/kg), reserpine (7.5 mg/kg), alpha-methyl-p-tyrosine (250 mg/kg) and scopolamine (0.5 mg/kg) markedly reduced yawning induced by desipramine, whereas prazosin (1 mg/kg) and phenoxybenzamine (5 mg/kg) were without effect. These findings indicate that desipramine induces yawning by a dopaminergic mechanism, and that endogenous dopamine (DA) is necessary for its occurrence. Yawning was observed also after administration of imipramine, clomipramine, trazodone, its metabolite m-chlorophenylpiperazine and (+/-)sulpiride. These drugs given in a similar dose-range to desipramine produced a weaker effect than desipramine. Selective and potent inhibitors of the uptake of noradrenaline (NA) or 5-hydroxytryptamine (5-HT), (+)oxaprotiline and citalopram, did not elicit yawning. A possibility is considered that certain antidepressant drugs induced yawning through an influence on dopaminergic system.
mesh_terms: D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology*; D003891:Desipramine / Q000494:pharmacology*; D004347:Drug Interactions; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D010879:Piperazines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects; D012018:Reflex / Q000187:drug effects*; D012601:Scopolamine / Q000494:pharmacology
chemical_list: D000928:Antidepressive Agents; D010879:Piperazines; D011954:Receptors, Dopamine; D012601:Scopolamine; D006220:Haloperidol; C015068:1-(3-chlorophenyl)piperazine; D003891:Desipramine