Comparative effects of five different calcium channel blockers on the atropine‐resistant contraction in electrically stimulated rabbit urinary bladder

Abstract

The effects of the calcium channel blockers nifedipine, verapamil, diltiazem, flunarizine, and lidoflazin on electrically induced contractions of isolated rabbit detrusor were compared in the absence and presence of muscarinic receptor blockade with scopolamine. All drugs had a depressant effect on the contractions both before and after scopolamine addition, nifedipine being the most potent of the calcium channel blockers. However, only nifedipine showed a significant preference for the nonmuscarinic part of the contraction, which was almost abolished at a concentration of M. It is concluded that combined muscarinic receptor and calcium channel blockade is an effective means of inhibiting bladder contraction. Differences between calcium channel blockers may be of importance in this respect.

Inhibitory effects of propiverine, atropine and oxybutynin on bladder instability in rats with infravesical outlet obstruction

“…[ 22] showed in the rat bladder that decreasing the calcium influx with a calcium‐channel blocker was more effective in inhibiting the atropine‐resistant component of the contraction induced by electrical‐field stimulation than was α,β‐methylene ATP. Again, the bladder instability seen in obstructed rats seems to be particularly related to the atropine‐resistant contraction component [ 23, 24] that is highly sensitive to calcium antagonists [ 25].…”

The pharmacological treatment of urinary incontinence

“…Available information does not suggest that systemic therapy with calcium antagonists is an effective way to treat detrusor overactivity, but controlled clinical trials are lacking. However, the possibility that intravesical therapy with these drugs could be useful should not be ignored, nor the fact that calcium antagonists may enhance the effects of antimuscarinic agents (Andersson et al 1986). Oral nifedipine has been used effectively as prophylaxis for autonomic hyperreflexia during urologic instrumentation in spinal cord injured patients (Wein 2001b).…”

Treatment of overactive bladder: other drug mechanisms

“…49 There is a pOSSibility that intravesical therapy with calcium antagonists may be useful, and calcium antagonists may enhance the effects ofantimuscarinic agents. 50 Some drugs used to treat overactive bladder have been shown to have more than one mechanism of action. They all have a more or less pronounced antimuscarinic effect and, in addition, an often poorly defined "direct" action on bladder muscle.…”