system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Mechanism of action of NO -
assistant
The correct answer is  Ans. is 'b' i.e., |cGMP o Nitric oxide (NO) released from parasympathetic nonadrenergic noncholinergic (NANS) nerves and vascular endothelium is the major neurotransmitter causing relaxation of smooth muscles of arteries, arterioles and trabeculae of sinusoids, i.e., NO is the major transmitter responsible for penile erection.o NO causes smooth muscle relaxation by generating cGMP.o cGMP is degraded by the enzyme phosphodiesterase, especially isoenzyme phosphodiesterase type 5 (PDE-5) which is selectively active in penile smooth muscles.