Neuronally released and applied acetylcholine on the longitudinal muscle of the guinea-pig ileum.

摘要: Abstract Brief transmural stimuli, which selectively excited cholinergic fibres, initiated contractions and excitatory junction potentials in preparations of longitudinal muscle isolated from the guinea-pig ileum: these responses were associated with an increase internal concentration calcium ions. When voltage-dependent channels blocked using organic antagonist nifedipine, brief stimuli continued to initiate contractions, evoke cause intracellular concentration. Ionophoretically applied acetylcholine caused depolarizations resembled evoked by nerve stimulation. Both had slow time courses abolished muscarinic receptor antagonists. However, produced ionophoretically acetylcholine, unlike those stimulation, frequently interrupted transient hyperpolarizations. The hyperpolarizations barium ions or charybdotoxin. High concentrations antagonists nicardipine, verapamil diltiazem a tendency preferentially abolish potential. effects cholinesterase inhibitor, eserine, on examined, it became apparent that when destruction was prevented additional conductance change untreated tissues. results are discussed relation idea neuronally released might activate different subsets receptors ileal smooth muscle.