【摘要】 本实验采用30只昆明产家兔,分单纯低氧(H)、酚妥拉明+低氧(PhH)、去甲肾上腺素+低氧(NH)三组。用去甲肾上腺素(α-肾上腺素能受体兴奋剂)提高低氧前血管张力,用酚妥拉明(α-肾上腺素能受体阻断剂)降低血管张力,以观察血管张力不同时对急性低氧所致肺动脉加压反应的影响。实验结果表明:低氧时肺动脉压升压强度为PhH组>H组>NH组。以肺动脉舒张压变化显著,其最大升压百分率,PhH组为37.79%;H组为30.66%;NH组为9.32%,(P<0.05)。说明用去甲肾上腺素增高低氧前的肺血管张力,可使肺动脉加压反应减弱;用酚妥拉明降低低氧前的肺血管张力,可使肺动脉加压反应增强。进而提示α-肾上腺素能受体可能参予调节肺血管张力,影响低氧性肺动脉加压反应的强度。更多还原

【Abstract】 The purpose of this study was to investigate whether the hypoxic pulmonary vasopressor response （HPPR） in intact anesthetized rabbits was related to the pulmonary vascular tone （PVT） before hypoxia.30 rabbits bred in Kunming （alt. 1895 M, 2.64±0.46, +SD, kg in wt）were divided into three groups. 1. Hypoxia （H）; 2. Hypoxia pretreated with phentolamine （PhH）; 3. Hypoxia pretreated with norepinephrine （NH）. During the period of experiments the rabbits were kept spontaneously breathing. Pulmonary arterial systolic and diastolic pressure （PAPs and PAPd）, femoral arterial systolic and diastolic pressure（FAPs and FAPd）, etc. were recorded with a RM-6000 polygraph system（Nihon Kohden）.The arterial blood gases were analysed by a DH-100 blood gas analyzer（Nanjing）. The animals inspired separately room air or 10±1% O₂ in 90±1% N₂ gas mixture through respiratory valves connected to Douglas’bags. Drugs used in the study were 1. norepinephrine bitartratis （Guangzou, 4μg/kg wt i.v.） for enhancing PVT before hypoxia; 2. phentolamine （Regitine/ciba, 8μg/kg wt i.v.）for decreasing PVT before hypoxia. The data were statistically calculated with F test. The results showed that both PAPs and PAPd increased during hypoxia, and PAPd response was more dominant than that of PAPs. Statistically significant difference in PAPd response was found in all three groups. The range of increments in PAPd is PhH>H>NH （37.79%; 30.66%; 9.32%, respectively P<0.05）.It was likely that the HPPR was enhanced when the vascular tone was decreased by phentolamine, while the HPPR blunted when the vascular tone increased by norepinephrine. Thus, the extent of HPPR is related to PVT before hypoxia. These observations imply that α-adrenergic receptor may influence the range of HPPR by modulating PVT before hypoxia. In addition, it was found that the FAPs and FAPd were blunted markedly after hypoxia when the vascular tone was enhanced by norepinephrine. It was similar to PAP response. There was no statistically significant difference in PaO₂ among three groups during hypoxia.更多还原