Estradiol effect on indomethacin and prostaglandin E2-modulation of adrenergic transmission in rabbit oviduct.
The effect of prostaglandin E2 /PGE2/ and indomethacin on 3H-noradrenaline (3H-NA) release- and on contractions-evoked by field electrical stimulation (FES) was studied in vitro in oviductal isthmus of mature rabbits (untreated and treated with estradiol). FES evoked guanethidine-sensitive contractions and calcium-dependent tritium overflow, which reflected 3H-NA overflow. Marked and concentration-dependent decrease of FES-evoked contractions by PGE2 (0.1-100 nM) was observed in both groups of animals. The inhibitory effect of PGE2 was more pronounced in estradiol treated animals (IC50 1.5 nM, n = 9) than in untreated animals (IC50 18 nM, n = 6). Indomethacin, 1 microM, induced a remarkably pronounced increase of FES-evoked contractions in estradiol treated (by 57.3 +/- 6.3%, n = 8) in comparison with untreated rabbits (21.4 +/- 3.8%, n = 7). The amount of FES-evoked release of tritium was significantly higher in untreated than in estradiol treated rabbits. PGE2 decreased and indomethacin increased tritium-evoked release. The effects of PGE2 and indomethacin on tritium-evoked release showed no estradiol dependence. The competitive results of PGE2 and indomethacin on both evoked contraction and 3H-NA release suggest that endogenous prostaglandin E2 takes part in modulation of adrenergic mediated contraction and that estradiol enhanced the prostaglandin effect.
Chernaeva
L
L
Institute of Physiology, Bulgarian Academy of Sciences, Sofia.
Charakchieva
S
S
D000320:Adrenergic Fibers / Q000187:drug effects*; D000818:Animals; D015232:Dinoprostone / Q000494:pharmacology*; D004558:Electric Stimulation; D004958:Estradiol / Q000494:pharmacology*; D005187:Fallopian Tubes / Q000187:drug effects / Q000294:innervation* / Q000502:physiology; D005260:Female; D007213:Indomethacin / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects; D009638:Norepinephrine / Q000378:metabolism; D010477:Perfusion; D011817:Rabbits; D012964:Sodium / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects
D004958:Estradiol; D012964:Sodium; D015232:Dinoprostone; D009638:Norepinephrine; D007213:Indomethacin