title: Area postrema mediates gastric motor response induced by apomorphine in rats.
abstract: The effects of apomorphine administration on the autonomic responses were investigated in rats. Distinctive gastric motor responses were observed after the intravenous administration of apomorphine (0.1 mg/kg body weight). Gastric motor responses in the distal stomach induced by apomorphine administration were classified into two types. One type involved inhibition of phasic contractions which appeared just after the administration of apomorphine. The other involved an increase in the frequency of small phasic contractions accompanied by increased gastric tone appearing with a relatively longer delay. No relaxation was observed in either the proximal or distal stomach. These gastric motor responses showed a dose-response effect to the amount of apomorphine administered (0.002-0.1 mg/kg body weight). In addition, submandibular salivary secretion was observed in response to the intravenous administration of apomorphine at a dose of 3 or 10 mg/kg body weight. Pretreatment with domperidone (1 or 2 mg/kg body weight) or the ablation of the area postrema (AP) abolished the gastric motor response and salivary secretion induced by the administration of apomorphine. In conclusion, rats showed definitive autonomic phenomena in response to the administration of apomorphine. Dopamine 2-like receptors situated in the AP mediate apomorphine-induced autonomic phenomena in rats.
authors.affiliation: Department of Restorative Science, Kawasaki University of Medical Welfare, Kurashiki 701-0193, Japan.
authors.forename: Tomoshige
authors.initials: T
authors.lastname: Koga
authors.forename: Motoi
authors.initials: M
authors.lastname: Kobashi
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Mizutani
authors.forename: Goichi
authors.initials: G
authors.lastname: Tsukamoto
authors.forename: Ryuji
authors.initials: R
authors.lastname: Matsuo
mesh_terms: D000818:Animals; D001058:Apomorphine / Q000008:administration & dosage / Q000494:pharmacology*; D031608:Area Postrema / Q000502:physiology*; D001341:Autonomic Nervous System / Q000187:drug effects; D004294:Domperidone / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004639:Emetics / Q000008:administration & dosage / Q000494:pharmacology*; D005769:Gastrointestinal Motility / Q000187:drug effects*; D007275:Injections, Intravenous; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012472:Salivation / Q000187:drug effects; D012798:Sialorrhea / Q000139:chemically induced; D013270:Stomach / Q000187:drug effects*; D013363:Submandibular Gland / Q000187:drug effects / Q000378:metabolism; D014628:Vagotomy
chemical_list: D018492:Dopamine Antagonists; D004639:Emetics; D004294:Domperidone; D001058:Apomorphine