Effects of morphine and opioid peptides on sensitivity to acetylcholine of dialysed snail neurons.
The effects of intracellular and extracellular applications of morphine (in concentrations from 10(-3) to 10(-5) M), leucine-enkephalin and methionine-enkephalin (10(-6) to 10(-8) M) were studied in unidentified acetylcholine-sensitive dialysed neurons of a snail under voltage clamp. Morphine produced inward membrane currents, while enkephalins did not. Both morphine and enkephalins altered the effect of acetylcholine on postsynaptic acetylcholine receptors; intracellular application of these substances being much more effective than extracellular application. This suggested that opioid peptides take part in the regulation of cholinergic synaptic transmission.
D000109:Acetylcholine / Q000494:pharmacology / Q000502:physiology*; D000818:Animals; D003956:Dialysis; D004723:Endorphins / Q000494:pharmacology*; D006372:Helix, Snails; D008564:Membrane Potentials / Q000187:drug effects*; D009020:Morphine / Q000494:pharmacology*; D009474:Neurons / Q000145:classification / Q000187:drug effects / Q000502:physiology*
D004723:Endorphins; D009020:Morphine; D000109:Acetylcholine