What does Nitric oxide have to do with regard to breathing rate or the Respiratory System?

Question

Thank you!!

Answer 1

Nitric oxide is a neurotransmitter as well as an intracellular signalling transmitter.  Regarding the effects of breathing, nitric oxide can cause the relaxation of smooth muscle.  One of the most famous cases of this interaction is with the drug viagra.  Essentially, an increase in nitric oxide causes the relaxtion of various smooth muscle systems.  Veins and arteries are part of the smooth muscle system, as well as various muscles located in the trachea, bronchii, and lungs.  Within the cardiovascular system, nitric oxide will cause the relaxation of veins, which allows blood to flow easier, which reduces the load on the heart.  If the heart doesn't have to beat as hard, the body will respond by lowering its breathing rate.  Also, since the smooth muscle within the lungs is relaxed in response to NO, air will flow easier into and out of the lungs, which will lower the body's breathing rate.  Hope this helps.