The mechanosensitive nonselective cation channel (NSC<sub>MS</sub>) is a key player in vascular myogenic contraction. The functional channel density and pressure sensitivity of NSC<sub>MS</sub> in vascular myocytes were compared between pulmonary and systemic arteries (coronary, mesenteric and cerebral arteries) in the rabbit. In cell-attached condition, a negative pressure via patch pipettes commonly activated NSC<sub>MS</sub> with weak voltage dependence. The threshold pressure for activation was lower, and the density of NSC<sub>MS</sub> was higher in the pulmonary than the systemic arteries. When the pulmonary arteries were divided into small-diameter (outer diameter, OD < 0.5 mm) and large-diameter (OD > 1.5 mm) arteries, the low threshold and high density of NSC<sub>MS</sub> were observed only in small-diameter ones. No such difference was observed between the small- and large-diameter coronary arteries. The higher stretch sensitivity and denser functional expression of NSC<sub>MS</sub> in small pulmonary arteries might suggest an adaptive tuning for the relatively low pulmonary blood pressure in vivo.