title: Extracellular recording from the guinea-pig myenteric plexus and the action of morphine.
abstract: Extracellular recordings were made with glass suction electrodes from neurons in isolated ganglia of the myenteric plexus of the guinea-pig ileum. The activity recorded was considered to arise in neuronal somata as a consequence of the mechanical contact with the recording electrode. The spike activity was depressed by normorphine (10 nM-1 micrometer) and this action was prevented by low concentrations of naloxone. Morphine remained effective in solutions which contained 1 or 12 mM K+. The findings support other evidence that morphine acts by hyperpolarizing the soma membrane of myenteric neurons, but do not elucidate the ionic mechanism of the effect.
mesh_terms: D000200:Action Potentials / Q000187:drug effects*; D000818:Animals; D002118:Calcium / Q000502:physiology; D004347:Drug Interactions; D004566:Electrodes; D005110:Extracellular Space / Q000187:drug effects; D006168:Guinea Pigs; D009020:Morphine / Q000494:pharmacology*; D009197:Myenteric Plexus / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D009270:Naloxone / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D009270:Naloxone; D013779:Tetrodotoxin; D010042:Ouabain; D009020:Morphine; D002118:Calcium