THE EFFECTS OF LITHIUM, INDOMETHACIN, AND NEOMYCIN ON VASOPRESSIN-INDUCED CONTRACTIONS IN RAT URINARY-BLADDER

1. [Arg(8)]Vasopressin (AVP) induced a contraction response in rat uri nary bladder smooth muscle in a dose-dependent manner. 2. Indomethacin in a 10-mu M concentration cannot change the effects of AVP on urinar y bladder smooth muscle, which seem to be mediated by a direct action on the muscle rather than indirectly through prostanoid release. 3. Li thium (0.5, 1, and 10 mM) made the muscle more sensitive to AVP action . 4. Neomycin (1.25, 2.5, and 5 mM) had an inhibitory effect on AVP-in duced contraction. 5. It seems that in rat urinary bladder vasopressin -induced contraction is mediated through phosphoinositide metabolism. (C) 1997 Elsevier Science Inc.