Possible role of prostaglandins in post-tetanic potentiation at the nerve-muscle junction in the longitudinal muscle strip of guinea-pig ileum.
The effect of tetanic stimulation on the twitch responses of the longitudinal muscle-myenteric plexus preparation of the guinea-pig ileum to electrical stimulation was investigated in the presence of naloxone. Under this condition, or after the addition of PGE2, twitch contractions were maximal and no potentiation of twitches following tetanus was observed. In the presence of indomethacin (1 mumol litre-1) twitches were diminished and post-tetanic potentiation (PTP) was manifested. PTP was seen with indomethacin concentrations of 1 to 20 mumol litre-1 or after simultaneous addition of diphloretin phosphate (16 mumol litre-1). Thus it seems unlikely that the effect of prostaglandins released during tetanic stimulation would be of key importance for the manifestation of PTP. Rather it is thought that a decrease in the release of acetylcholine from motor nerve terminals, and consequently smaller twitches in the presence of indomethacin, offer favourable conditions for PTP.
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D009469:Neuromuscular Junction / Q000187:drug effects*; D011453:Prostaglandins / Q000502:physiology*
D011453:Prostaglandins; D000109:Acetylcholine; D007213:Indomethacin