Carbachol-induced reverse transformation of Chinese hamster ovary cells transfected with and expressing the m5 muscarinic acetylcholine receptor

Abstract

Reverse transformation was induced in Chinese hamster ovary (CHO) cells transfected with and stably expressing the m5 subtype of the muscarinic acetylcholine receptor when stimulated with the muscarinic agonist, carbachol. Atropine, a muscarinic antagonist, blocked the carbachol-stimulated reverse transformation. CHO cells not transfected with the muscarinic receptor did not change with added carbachol. PMA induced reverse transformation without increasing cAMP accumulation in CHO cells. Carbachol, prostaglandin E 2, and cholecystokinin increased cAMP accumulation but only carbachol caused reverse transformation. Carbachol-stimulated cAMP accumulation occurred at a higher concentration (EC 50 10 μM) than did carbachol-stimulated reverse transformation (EC 50 63 nM). Muscarinic m5 acetylcholine receptor transfected into CHO cells can induce reverse transformation which may be independent of cAMP.