The M3 muscarinic receptor mediates acetylcholine-induced cortisol secretion from bovine adrenocortical zona fasciculata/reticularis cells.
In order to characterize the receptor subtype mediating acetylcholine (ACh)-induced cortisol secretion from purified bovine adrenocortical zona fasciculata/reticularis cells in primary culture, the potencies of a range of selective muscarinic antagonists of ACh-induced steroidogenesis were assessed by Schild analysis. Basal secretion of cortisol was 10.2 +/- 1.4 pmol/well/30 min. ACh stimulated a dose-dependent increase in cortisol secretion and was maximally effective at 10(-5) M, at which concentration cortisol secretion was 143.4 +/- 12.9 pmol/well/30 min. Hexahydro-sila-difenidol and para-fluoro-hexa-hydro-sila-difenidol were potent competitive antagonists of ACh-stimulated cortisol secretion, with pA2 values of 8.68 +/- 0.28 and 7.96 +/- 0.29, respectively. Pirenzepine (pA2 = 6.95 +/- 0.28) and methoctramine (pA2 = 6.06 +/- 0.27) were relatively weak competitive antagonists. The pA2 values determined in this study are characteristic of the M3 muscarinic receptor, and we conclude that this receptor subtype mediates ACh-induced cortisol secretion from bovine zona fasciculata/reticularis cells.
Clyne
C D
CD
Department of Pharmacology, Royal Infirmary, Edinburgh, U.K.
Walker
S W
SW
Nicol
M R
MR
Williams
B C
BC
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D006854:Hydrocortisone / Q000378:metabolism*; D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic / Q000502:physiology*; D015383:Zona Fasciculata / Q000187:drug effects* / Q000378:metabolism; D015385:Zona Reticularis / Q000187:drug effects* / Q000378:metabolism
D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic; D000109:Acetylcholine; D006854:Hydrocortisone