The muscarinic receptor of rat pituitary GH3 cells is coupled with adenylate cyclase inhibition, but not with phosphoinositide turnover.
The effects of muscarinic stimulation on cyclic AMP accumulation and on basal and thyrotropin-releasing hormone (TRH)-induced phosphoinositide turnover have been studied in rat pituitary GH3 tumour cells. Carbachol produced a dose-dependent atropine-sensitive inhibition of basal cyclic AMP accumulation. It had no effect on basal or TRH-stimulated production of inositol phosphates. The majority of the muscarinic receptors had a low affinity (Ki 0.22 microM) for pirenzepine and can be classified as M2 type, inhibiting adenylate cyclase but having no links with phosphoinositide metabolism.
Yagisawa
H
H
Department of Biochemistry, University of Nottingham Medical School, Queen's Medical Centre, U.K.
Simmonds
S H
SH
Hawthorne
J N
JN
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D007295:Inositol Phosphates / Q000378:metabolism; D019832:N-Methylscopolamine; D010716:Phosphatidylinositols / Q000378:metabolism*; D010890:Pirenzepine / Q000494:pharmacology; D010902:Pituitary Gland / Q000502:physiology*; D051381:Rats; D011976:Receptors, Muscarinic / Q000502:physiology*; D012602:Scopolamine Derivatives / Q000378:metabolism; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D007295:Inositol Phosphates; D010716:Phosphatidylinositols; D011976:Receptors, Muscarinic; D012602:Scopolamine Derivatives; D010890:Pirenzepine; D013973:Thyrotropin-Releasing Hormone; D002217:Carbachol; D000262:Adenylyl Cyclases; D015056:1-Methyl-3-isobutylxanthine; D019832:N-Methylscopolamine