Rohlicek C V, Polosa C
Am J Physiol. 1981 Nov;241(5):H679-83. doi: 10.1152/ajpheart.1981.241.5.H679.
The relation between arterial O2 tension (PaO2) and the firing rate of sympathetic preganglionic neurons (SPN) of the cervical sympathetic trunk was studied during graded isocapnic hypoxia and hyperoxia in unanesthetized acute C-1 spinal cats. In the PaO2 range between 40 and 400 Torr there was no relation between the two variables. Below 40 Torr firing rate increased as PaO2 decreased, reaching an average peak value of ten times control at a PaO2 of 20 Torr. Mean arterial blood pressure (MABP) was also independent of PaO2 between 40 and 400 Torr and increased by an average of 25% at PaO2 values below 40 Torr. Intravenous administration of hexamethonium or phentolamine abolished the MABP response but not the SPN response to hypoxia. Pentobarbital (5-60 mg/kg iv) did not modify the SPN response to hypoxia, although normoxic SPN background firing was considerably depressed. The excitatory effect of hypoxia seems independent of excitatory afferent input and appears to be a general property of SPN.
在未麻醉的急性C-1脊髓猫中，于等碳酸性低氧和高氧分级过程中，研究了颈交感干动脉血氧分压（PaO2）与交感神经节前神经元（SPN）放电频率之间的关系。在40至400托的PaO2范围内，这两个变量之间没有关系。低于40托时，随着PaO2降低，放电频率增加，在PaO2为20托时达到平均峰值，为对照值的10倍。平均动脉血压（MABP）在40至400托之间也与PaO2无关，在低于40托的PaO2值时平均升高25%。静脉注射六甲铵或酚妥拉明可消除MABP对低氧的反应，但不能消除SPN对低氧的反应。戊巴比妥（5 - 60毫克/千克静脉注射）虽使常氧下SPN的背景放电明显受抑制，但不改变SPN对低氧的反应。低氧的兴奋作用似乎与兴奋性传入输入无关，且似乎是SPN的一种普遍特性。
