Imidafenacin exerts the antidiuretic effect by enhancing vasopressin-related responses in orally water-loaded rats.

Imidafenacin, an antimuscarinic agent for treating overactive bladder, has an antidiuretic effect, but the detailed mechanisms of action remain unclear. The cholinergic and vasopressin systems are known to interact, for example, in the suppression of vasopressin-induced water reabsorption through muscarinic stimulation in the renal collecting duct. We, therefore, investigated whether vasopressin signaling pathway would participate in the antidiuretic effect of imidafenacin. In female Sprague-Dawley rats, urine production was measured by collecting urine from cystostomy chatheter using a Bollman restraining cage for 2h after drug i.v. injection and water load (25ml/kg p.o.). Both imidafenacin and a vasopressin V