Posttetanic inhibition in the guinea - pig ileum by endogenous opiate ligands; effects of cold storage of the preparations and of the age of experimental animals.
Naloxone-sensitive inhibition of neurogenic twitch contractions was induced by tetanic stimulation of the myenteric plexus-longitudinal muscle preparation of the guinea-pig ileum. In preparations stored in the cold for more than 2 days, the inhibition disappeared and in some preparations posttetanic potentiation was manifested, instead. Thus enkephalinergic neurones are more sensitive to the effect of cold storage than cholinergic neurones. The naloxone-sensitive posttetanic inhibition was developed in newborn animals but in animals older than 3 years a naloxone-resistent component appeared.
D000109:Acetylcholine / Q000494:pharmacology; D000375:Aging; D000818:Animals; D003080:Cold Temperature; D004558:Electric Stimulation; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction; D009270:Naloxone / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*
D009270:Naloxone; D000109:Acetylcholine