Effect of Ca2+ antagonists on isolated rabbit detrusor muscle

Ca(2+)-antagonists change the contractility of isolated detrusor smooth muscle of rabbit influencing the translocation of intra- and extra-cellular Ca2+. This observation might be of clinical importance in the treatment of disorders of urinary bladder function. During field stimulation of different segments of isolated rabbit bladder it was found that the specific Ca(2+)-antagonist nifedipine and verapamil and the non-selective Ca(2+)-antagonist fendiline, prenylamine and cinnarizine blocked the contractions induced by field stimulus to different extent, which decreased from the bladder towards the bladder base (fundus). The highest rate of blocking effect was produced by nifedipine followed by verapamil, prenylamine and fendiline, respectively. Cinnarizine exerted the lowest effect. The change in amplitude and frequency of spontaneous peristalsis was similar in its tendency to the blockade of the field stimulus induced contraction.