The role of cyclic GMP in cells with the properties of smooth muscle cultured from the rat myometrium

✍ Scribed by J. Frederick Krall; Anne Morin

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 900 KB
• Volume: 129
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1041290217

✦ Synopsis

Cells growing in culture with previously described properties of rat uterine smooth muscle accumulated Ca2+ from the medium. Ca2+ uptake by these cells was stimulated b the addition to the medium of 8-bromo-cCMP but not by 8-bromo-CAMP. Cay+ uptake was also stimulated by carbachol and by the nitro-vasodilator nitroprusside. Although cholinergic agonists have been shown previously to stimulate contraction but not cGMP synthesis in the rat myometrium, both carbachol and nitroprusside stimulated cGMP production by the cultured cells. These results suggested the cells had cholinergic receptor-mediated functions that reflected some neurotransmitter-sensitive properties of uterine smooth muscle in situ. When determined by a specific radioligand binding assay, subcellular fractions of the cultured cells bound muscarinic cholinergic agonists and antagonists with affinities expected of the muscarinic receptor.

The cells were also sensitive to the P-adrenergic catecholamine agonist isoproterenol, which stimulated cAMP production but not Ca2+ uptake. Carbachol failed to inhibit isoproterenol-dependent cAMP production, which is an important property of the cholinergic receptor in uterine smooth muscle in situ. These results suggest some but not all acetylcholine-sensitive properties of uterine smooth muscle may be retained in cell culture.

Changes in cyclic nucleotide levels characterize the regulation of smooth muscle tension by a variety of hormones and neurotransmitters (Schultz et al. 1973; Scheid et al., 1979). Many of these physiologically active