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AIM and METHODS: Total RNA was extracted from 6th rat subcultured pulmonary artery smooth muscle cells(PASMC) exposed to continual chronic hypoxia or normoxia and the effects of chronic hypoxia on the changes of Kv1.3,Kv2.1,Kv3.1 mRNA in cultured PASMC induced by acute hypoxia were studied by semiquantitative RT-PCR in vitro. RESULTS:①Kv1.3,Kv2.1,Kv3.1 genes were found to be expressed in PASMC of rats exposed either to hypoxia or normxia.②The expression of Kv2.1 and Kv3.1 in 6th subcultured of PASMC in normaxia group could be upregulated by exposure to acute hypoxia,the levels of Kv2.1 and Kv3.1 mRNA were significantly increased from 0.646?0.092, 0.782?0.104 to 1.059?0.134, 0.985?0.116,respectively (P
ABSTRACT
AIM and METHODS: To determine the role of different K +-channels in attenuation of vasoreactivity of intrapulminary artery rings induced by chronic hypoxia. RESULTS: ①Acute hypoxia-induced pulmonary vasoconstriction(HPV) could be significantly attenuated by chronic hypobaric hypoxia for 15 days and for 30 days. ②HPV could be significantly potentiated by ATP-sensitive K +-channel (K ATP ) blocker or Ca 2+ -activated K +-channel (K Ca )blocker, and the potentiated scope in chronic hypoxic group was much higher than that observed in control group. ③ Delayed rectifier K +-channel (K DR )blocker showed no effect on HPV in both control group and chronic hypoxic group.CONCLUSIONS: Both K ATP and K Ca play an important modulating role in HPV and it's potentiation may be a critical mechanism for the attenuated vasoreactivity to acute hypoxia; following chronic hypobaric hypoxia.
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AIM: To detect the role of cyclic nucleotides in the alleviation of hypoxic pulmonary vasoconstriction (HPV) in chronic hypoxic animals. METHODS: The intracellular cAMP and cGMP of the cultured porcine pulmonary arterial smooth muscle cells (PASMC) and endothelial cells (PAEC) were assayed by RIA. The length of single PASMC during acute hypoxia was measured by imaging analysis system. RESULTS: The basal levels of cAMP and cGMP in PASMC and cGMP in PAEC of Chronic hypoxic groups decreased remarkably compared with normoxic groups ( P
ABSTRACT
AIM:To determine the role of Kv1 2, Kv1 5, Kv2 1 in the hypoxia pulmonary vasoconstriction (HPV). METHODS: Male Wistar rats were divided into two groups: normoxic group and hypoxic group. The single smooth muscle cell was obtained from pulmonary artery of Wistar rats with acute enzymatic digestion method. The conventional whole-cell patch clamp technique was used to record the resting membrane potential (Em) and the potassium currents of voltage-gated potassium channel (IKv) in rat pulmonary arterial smooth muscle cells (PASMC). Intracellular application of Kv1 2/Kv1 5/Kv2 1 antibodies (1∶125) was conducted through the whole-cell patch clamp system. RESULTS: ① Em of PASMC was depolarized after 24 h hypoxia compared with that of control cells [from (-51 8?0 8) mV to (-47 2? 0 7) mV, P