Evidence that morphine and opioid peptides do not share a common pathway with adenosine in inhibiting acetylcholine release from isolated intestine.
1 The release of acetylcholine from guinea-pig ileal isolated longitudinal muscle strip with intact Auerbach's plexus was measured by bioassay and by a radioisotope technique. 2 Normorphine (5 x 10(-7)M) and D-Met2, Pro5-enkephalinamide (D-Met, Pro-EA) reduced the release of acetylcholine. Theophylline, an adenosine antagonist, failed to prevent the inhibitory effect of normorphine or D-Met, Pro-EA. 3 Theophylline (1.7 x 10(-4)M) by itself enhanced the twitch responses to field stimulation (0.1 Hz) but did not prevent the inhibitory effect of normorphine and D-Met, Pro-EA. 4 From the results it can be concluded that morphine and opioid peptides do not share a common pathway with adenosine in inhibiting acetylcholine release from axon terminals of Auerbach's plexus.
D000109:Acetylcholine / Q000378:metabolism*; D000241:Adenosine / Q000502:physiology*; D000818:Animals; D004558:Electric Stimulation; D004723:Endorphins / Q000494:pharmacology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects; D009020:Morphine / Q000494:pharmacology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism*; D009197:Myenteric Plexus / Q000187:drug effects; D013806:Theophylline / Q000494:pharmacology
D004723:Endorphins; D009020:Morphine; D013806:Theophylline; D000241:Adenosine; D000109:Acetylcholine