[Effects of anisodine on respiratory center].
Anisodine (Ani), a new selective M receptor blocking agent, was isolated from Scopolia tangutica in China. The structure of Ani is similar to scopolamine. Ani (2.5, 5 mg.kg-1 i.v., or 0.6 mg.kg-1 icv) increased the rate of phrenic nerve discharges (PND), while the time of inspiration and expiration, and the spikes in each PND were reduced in urethan-anesthetized rats. In urethan-anesthetized rabbits, Ani (2.5 mg.kg-1 i.v., or 0.2 mg.kg-1 applied onto obex) increased the rate of PND. In tubocurarine-pretreated and artificially ventilated rabbits, Ani (2.5 mg.kg-1 i.v., or 0.2 mg.kg-1 applied onto obex) increased the rate of inspiratory neurone firing in nucleus tractus solitarius. Oxotremorine (40 micrograms.kg-1 i.v.) antagonized the Ani effects. Ani (2.5 mg.kg-1 i.v.) partially antagonized the respiratory depression induced by morphine. These results provide the evidence that Ani stimulates the respiratory center through cholinergic M pathway and there may be some neuronal interaction between cholinergic and opiate receptors in the control of respiratory center.
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Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing.
Chen
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D000818:Animals; D004594:Electrophysiology; D008297:Male; D009020:Morphine / Q000037:antagonists & inhibitors; D018727:Muscarinic Antagonists; D010095:Oxotremorine / Q000494:pharmacology; D010791:Phrenic Nerve / Q000502:physiology; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D012119:Respiration / Q000187:drug effects*; D012125:Respiratory Center / Q000187:drug effects*; D012602:Scopolamine Derivatives / Q000494:pharmacology*; D017552:Solitary Nucleus / Q000502:physiology
D018727:Muscarinic Antagonists; D012602:Scopolamine Derivatives; D010095:Oxotremorine; D009020:Morphine; C012183:anisodine