Effect of opioid peptides on electrically evoked acetylcholine release from Torpedo electromotor neurons.
The opioid peptide dynorphin A(1-8) (1 micron) increased acetylcholine release from the Torpedo electric organ by approximately twofold. This effect was reversed by the opiate antagonist naloxone. The effect of Dyn A(1-8) on acetylcholine release was found to vary in magnitude with the seasons of the year, with maximal enhancement being observed in the summer and none in winter. Dynorphin B, methionine-enkephalin and leucine-enkephalin also increased acetylcholine release and showed similar seasonal variations. These findings suggest that acetylcholine release from Torpedo electromotor neurons is regulated by opiate receptors. The physiological significance of these observations is discussed in view of the previous findings that the Torpedo neurons contain an endogenous enkephalin-like peptide.
Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel.
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Oron
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Sarne
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Michaelson
D000064:Acclimatization; D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D004399:Dynorphins / Q000494:pharmacology; D004557:Electric Organ / Q000187:drug effects / Q000502:physiology*; D004558:Electric Stimulation; D004723:Endorphins / Q000494:pharmacology*; D004743:Enkephalin, Leucine / Q000494:pharmacology; D004744:Enkephalin, Methionine / Q000494:pharmacology; D066298:In Vitro Techniques; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology*; D009270:Naloxone / Q000494:pharmacology; D012621:Seasons; D014101:Torpedo
D004723:Endorphins; D009270:Naloxone; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D004399:Dynorphins; D000109:Acetylcholine