Isolation and contractile responses of single pregnant rat myometrial cells in short‐term primary culture and the effects of pharmacological and electrical stimuli

Abstract

1 A modified method for enzymatically isolating myometrial cells from the pregnant rat has been developed and the mechanical properties of single cells in short-term primary culture have been studied in response to various stimuli. 2 The dissociation method produced a high proportion of fully relaxed cells and these cells shortened and subsequently relaxed completely in response to successive applications of acetylcholine, angiotensin II, high K⁺ solution or depolarizing current. 3 In single cells, the contractions induced by acetylcholine and high K⁺ solution were concentration-dependent. Maximal contractions were obtained with 135.6 mm K⁺ and 5 × 10⁻⁴ m acetylcholine. 4 In single myometrial cells, the time course of contractions induced by acetylcholine, high K⁺ solution or depolarizing current was similar, suggesting that the rate of shortening was determined by limits of the contractile mechanism. 5 Scanning electron microscopy revealed a smooth surface to the relaxed cells which contrasted with the numerous evaginations present on fully contracted cells. 6 These results demonstrate the retention of structural integrity, acetylcholine and angiotensin II receptors, and potential-dependent Ca channels in myometrial single cells in short-term primary culture. Cells produced by this technique may provide a useful model for detailed electrophysiological studies.