Role of prostaglandins,nitric oxide and potassium channel in the blunting of hypoxic pulmonary vasoconstriction in the high altitude adaptive animal

AIM: To investigate the possible role of prostaglandin, NO and potassium channel in the adaptive blunting of hypoxic pulmonary vasoconstriction (HPV) in high altitude animal (pika). METHODS: The effect of L-NAME, indomethacin and 4-AP on the response of isolated lung strips of pika and Wistar rats instead of pulmonary artery to acute hypoxia were studied. RESULTS: (1) After inhibition of prostaglandins by indomethacin, the percentage increase in hypoxic constriction in lung tissue strip of pikas was greater than that in Wistar rats , P＜0.05; (2) After inhibition of NO synthesis by L-NAME, the percentage increase in hypoxic constriction in lung tissue strip of pikas was greater than that in Wistar rats , P＜0.05; (3) After administration of 4-AP, there was no significant difference in the percentage decrease in hypoxic constriction of lung tissue strip between pika and Wistar rat. CONCLUSIONS: (1) Prostaglandins and NO might modulate HPV in either rat of pika; the closure of Voltage-gated K⁺ channels might mediate HPV in either rat or pika. (2) Prostaglandins and NO might play an important role in the blunting of HPV in pika, Voltage-gated K⁺ channels may play a minor role in the blunting of hypoxic pulmonary vasoconstriction in pika.