Evidence for transmission through sympathetic ganglia mediated by muscarinic receptors in anesthetized guinea pigs.
3-Mercaptopropionic acid (3-MP), an inhibitor of the synthesis of GABA, acts in the central nervous system to increase arterial pressure (+50-60 mmHg) in anesthetized guinea pigs, apparently by sympathoadrenal activation. However, blockade of nicotinic receptors in autonomic ganglia with hexamethonium (10 or 20 mg/kg, i.v.) failed to effect any degree of sustained reversal of increases in blood pressure. Infusion of atropine methyl bromide (1 mg/kg, i.v.) likewise was without effect when administered alone, but completely reversed the hypertension induced by 3-MP when given after treatment with hexamethonium. These findings suggest that ganglionic transmission through either the "classical" nicotinic pathway or a muscarinic pathway is sufficient to sustain the sympathetically-mediated pressor response elicited by 3-MP.
D015097:3-Mercaptopropionic Acid / Q000494:pharmacology; D000758:Anesthesia; D000818:Animals; D001286:Atropine Derivatives / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D005728:Ganglia, Sympathetic / Q000502:physiology*; D006168:Guinea Pigs; D006584:Hexamethonium Compounds / Q000494:pharmacology; D008297:Male; D011976:Receptors, Muscarinic / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects*; D013997:Time Factors
D001286:Atropine Derivatives; D006584:Hexamethonium Compounds; D011976:Receptors, Muscarinic; C006649:methylatropine; D015097:3-Mercaptopropionic Acid