STREPTOZOTOCIN, AN INDUCER OF NAD(-POTASSIUM CURRENT INHIBITION BY ATP, BRADYKININ, ANGIOTENSIN-II, ENDOTHELIN-1 AND ACETYLCHOLINE IN NG108-15 CELLS() DECREASE, ATTENUATES M)

The M-potassium current was inhibited by bath application of 100 mu M ATP, 10 nM bradykinin, 100 nM angiotensin II and 100 nM endothelin 1 a s web as by 10 mu M acetylcholine in an ml-muscarinic acetylcholine re ceptor-transformed NG108-15 cell line. The inhibition of M-current was attenuated in cells pretreated with 5 mM streptozotocin for 5-15 h an d restored by simultaneous incubation with 5 mM nicotinamide. The resu lts suggest that signal transduction from these five different recepto rs to M channels shares a common pathway which is susceptible to a str eptozotocin-induced decrease in cellular NAD(+) content.