title: Action of serotonin and norepinephrine on spinal motoneurones following blockade of synaptic transmission.
abstract: The actions of serotonin and norepinephrine were investigated on spinal motoneurones in isolated, hemisected rat and frog spinal cords. Serotonin and norepinephrine induced slowly developing depolarizations of spinal motoneurones which were frequently preceded by brief, low amplitude hyperpolarizations. Neither the depolarizations nor the hyperpolarizations were attenuated by 20 mM Mg2+ or tetrodotoxin, although synaptic transmission was blocked in both cases. It thus appears unlikely that the action of serotonin and norepinephrine on spinal motoneurone polarization and results from an indirect action via interneurones.
mesh_terms: D000818:Animals; D004558:Electric Stimulation; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009046:Motor Neurons / Q000187:drug effects*; D009467:Neuromuscular Depolarizing Agents / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology*; D011894:Rana pipiens; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000494:pharmacology*; D013116:Spinal Cord / Q000187:drug effects; D013569:Synapses / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects*; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D009467:Neuromuscular Depolarizing Agents; D012701:Serotonin; D013779:Tetrodotoxin; D009638:Norepinephrine