Action of D-600 on spontaneous and electrically stimulated activity of the parturient rat uterus.
The effects of D-600, the methoxy derivative of verapamil, on the parturient rat uterus have been studied. At concentrations of 10(-8) to 10(-7) M, D-600 abolishes spontaneous contractions and reduces the force of electrically evoked contractions. The first action is associated with a reduction in amplitude of the slow waves (oscillations of membrane potential which underlie rhythmic bursts of spikes initiating contractions). The second is associated with a reduction in frequency of spikes within the bursts accompanying the electrically stimulated contractions. This reduction results from a decrease in the slope of the prepotential in cells in pacemaker areas of the muscle. D-600 also decreased the height and rising velocity of the conducted action potentials, but these actions cannot account entirely for the reduction in contractile force.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D003864:Depression, Chemical; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D005711:Gallopamil / Q000494:pharmacology*; D066298:In Vitro Techniques; D007743:Labor, Obstetric; D008564:Membrane Potentials / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D009215:Myometrium / Q000187:drug effects; D049590:Postpartum Period; D011247:Pregnancy; D051381:Rats; D014590:Uterine Contraction / Q000187:drug effects*; D014700:Verapamil / Q000031:analogs & derivatives*
D005711:Gallopamil; D014700:Verapamil