Bairam A, Hannhart B, Marchal F
Laboratoire de Physiologie, Faculté de Médecine de Nancy, France.
Acta Paediatr. 1994 Mar;83(3):236-40. doi: 10.1111/j.1651-2227.1994.tb18084.x.
Hypotension is known to affect the rate of carotid chemosensory activity in the adult cat, but the relationship between arterial blood pressure and carotid sinus nerve discharge has not been established in the kitten. The purpose of this study was to determine the response of carotid chemosensory afferents to hypotension induced in normoxia and in hyperoxia in eight kittens aged 1 to 25 days. Hypotension was obtained by a gradual decrease in blood volume. The activity of a few chemosensory fibres was recorded from one carotid sinus nerve. Baseline steady-state mean arterial blood pressure and carotid chemosensory activity were, respectively, 70.0 +/- 4.3 mmHg and 7.6 +/- 1.9 impulse/s (mean +/- SEM) in normoxia and 56.3 +/- 6.7 mmHg and 0.58 +/- 0.2 impulse/s in hyperoxia. Lowering arterial blood pressure below 37.5 +/- 3.5 mmHg in normoxia and 26.8 +/- 2.3 mmHg in hyperoxia was associated with a consistent increase in the rate of chemosensory discharge. Above this threshold, blood pressure variations had little effect on carotid chemoreceptor activity. These data are qualitatively similar to those of adult cats and provide evidence that, in newborn kittens, changes in arterial blood pressure will not influence carotid chemosensory discharge unless these changes are out of the physiological range.
已知低血压会影响成年猫的颈动脉化学感受活动速率，但在新生小猫中，动脉血压与颈动脉窦神经放电之间的关系尚未明确。本研究的目的是确定1至25日龄的八只小猫在常氧和高氧条件下，颈动脉化学感受传入神经对低血压的反应。通过逐渐减少血容量来诱导低血压。从一条颈动脉窦神经记录少数化学感受纤维的活动。在常氧条件下，基线稳态平均动脉血压和颈动脉化学感受活动分别为70.0±4.3 mmHg和7.6±1.9冲动/秒（平均值±标准误），在高氧条件下分别为56.3±6.7 mmHg和0.58±0.2冲动/秒。在常氧条件下将动脉血压降至37.5±3.5 mmHg以下，在高氧条件下降至26.8±2.3 mmHg以下，会导致化学感受放电速率持续增加。高于此阈值，血压变化对颈动脉化学感受器活动影响很小。这些数据在质量上与成年猫的数据相似，并提供了证据表明，在新生小猫中，除非动脉血压变化超出生理范围，否则不会影响颈动脉化学感受放电。
