['We sought to study the contribution of potassium channels in the effect of forskolin and 1,9-dideoxyforskolin on uterine contractility in the pregnant rat.', 'Rings taken from the middle portions of uterine horns from rats at 16 days of gestation were positioned in organ chambers containing physiologic salt solution bubbled with 5% carbon dioxide in air (37 degrees C, pH approximately 7.4) for isometric tension recording under 2 g passive tension. The effects of cumulative concentrations of forskolin and 1,9-dideoxyforskolin in the absence or presence of an adenylate cyclase inhibitor (MDL-12,330A, 10(-5) mol/L), a nonselective potassium channel blocker (tetrabutylammonium, 10(-4) mol/L), or an adenosine triphosphate-dependent potassium channel blocker (glibenclamide 10(-5) mol/L) were studied.', 'Both forskolin and, to a lesser extent, 1,9-dideoxyforskolin inhibit uterine contractions. Tetrabutylammonium, glibenclamide, and MDL-12, 330A attenuated the effects of forskolin, whereas glibenclamide was less effective against 1,9-dideoxyforskolin.'] Are adenylate cyclase and potassium channels involved in forskolin- and 1,9-dideoxyforskolin-induced inhibition of pregnant rat uterus contractility?