Role of K~+ channels in hypoxic pulmonary vasoconstriction in normal and chronic hypoxic rats / 中国病理生理杂志

ABSTRACT

AIM: To investigate the role of K + channels in the decreased hypoxic pulmonary vasoconstriction(HPV) in chronic hypoxic rats. METHODS: Blockers of three kinds of K + channels, 4-AP(voltage dependent K + channel blocker), TEA(Ca 2+ activated K + channel blocker)\, GLIB(ATP sensitive K + channel blocker) were used in isolated perfused rat lungs to detect the role of K + channels in HPV. RESULTS: In normal rats, 4-AP and TEA, but not GLIB, both elicited a significant increase in pulmonary artery baseline pressure, and also potentiated the acute hypoxic pulmonary vasoconstriction. In chronic hypoxic rats, the HPV is significantly decreased, while 4-AP, TEA, GLIB all elicited a significant but smaller increase in pulmonary artery baseline pressure. Additionally, all these three blockers potentiated the HPV stronger in chronic hypoxic rats than in control rats. CONCLUSION: The opening of Kv, K Ca , K ATP might modulate the hypoxic pulmonary vasoconstriction in isolated rat lungs, and the increase in this modulation by potassium channel in chronic hypoxic rats might play a role in its decrease in HPV.