title: Pre- and post-synaptic dopaminergic receptors involved in apomorphine-induced yawning.
abstract: The temporal course of yawning behavior elicited by increasing doses of apomorphine (APO), from 0.01 to 10 mg/kg, was studied experimentally in adult albino rats. In the higher dose range a great prolongation of drug induced yawning latency is observed. This result is explainable by postulating differences in sensitivity of two sets of dopaminergic (DA) receptors: low threshold presynaptic DA receptors which, when activated, disinhibit yawning, and high threshold postsynaptic DA receptors inhibiting yawning. Apomorphine in high doses can entirely suppress physostigmine-elicited yawning.
mesh_terms: D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D001921:Brain / Q000187:drug effects; D006801:Humans; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects*; D012119:Respiration / Q000187:drug effects; D013239:Stereotyped Behavior / Q000187:drug effects*; D013569:Synapses / Q000187:drug effects*
chemical_list: D011954:Receptors, Dopamine; D001058:Apomorphine