MODULATION BY PROSTAGLANDINS OF RELEASE OF ACETYLCHOLINE AND NORADRENALINE IN GUINEA-PIG ISOLATED ILEUM

  • 1 January 1978
    • journal article
    • research article
    • Vol. 205  (3) , 635-645
Abstract
The effects of prostaglandin(PG)E2, PGE2.alpha. and indomethacin on the release of acetylcholine (ACh), noradrenaline [norepinephrine] (NA) and prostaglandin-like substances from the isolated guinea-pig ileum and its longitudinal muscle-myenteric plexus preparation were investigated. The ACh and PG output was determined by a bioassay and the output of NA by an isotope technique. The output of ACh, both resting and stimulated, was decreased by indomethacin (1 .mu.M) especially after a longer exposure. The output of ACh was increased by PGE2 (6 nM) but not by PGF2.alpha.. This increase was inversely related to the initial level of ACh output; thus, it was marked only in the preparations with low initial output of ACh. Prostaglandin-like substances released from the ileum were mainly of the E type and their output only partially correlated with contractions and with the output of ACh. The stimulated outflow of NA at a frequency of 5 HZ was increased by indomethacin (50 .mu.M) and decreased by PGE2 (30 nM). PGE2.alpha. had no effect. These results suggest that PGE2 might act physiologically as a modulator of cholinergic transmission whereas its effect on adrenergic transmission could be of a pharmacological nature.