Second messenger for smooth muscle relaxation mediated by NO is:
(A) Ca' (B) cAMP (C) cGMP (D) Magnesium
(C) Ans: C. cGMPRef.: Harper 30/e p290, 437)Second messenger for smooth muscle relaxation mediated by NO is cGMP."GTP serves as an allosteric regulator and as an energy source for protein synthesis, and cGMP serves as a second messenger in response to nitric oxide (NO) during relaxation of smooth muscle.