牵拉左心房和夹闭颈总动脉对猫下丘脑前部和后部单位放电的影响

EFFECTS OF LEFT ATRIAL STRETCH AND CAROTID OCCLUSION ON THE SINGLE UNIT ACTIVITY OF ANTERIOR AND POSTERIOR HYPOTHAIAMUS IN CAT

在40只氯醛糖和乌拉坦麻醉的猫,观察了牵拉左心房肺静脉入口处(atrial stretch,AS)和关闭一侧颈总动脉(carotid occlusion,CO)对下丘脑前部(AH)和下丘脑后部(PH)单位放电的影响。共记录了185个自发放电单位。对 AS 有反应的 AH 和 PH 单位分别为46.3%和23.3%,其中均以出现抑制反应者居多。有少数单位仅在 AS 开始和停止时出现短暂的兴奋反应。在上述185个神经元中观察了85个对 AS 和 CO 两种刺激的反应,有15个(17.6%)对两种刺激均反应,其中被 AS 所抑制而为 CO 所兴奋的有11个,占73.3%(11/15)。这些结果表明:(1)AS 可对 AH 神经元活动起抑制作用;(2)AS 也可影响 PH 神经元活动;(3)动脉压力感受性和心房容量感受性刺激可会聚于同一下丘脑神经元。

The effects of left atrial stretch(AS)and carotid occlusion(CO)on the singleunit activity of anterior and posterior hypothalamus(AH and PH)were investi-gated in 40 urethan-chloralose-anesthetized cats.A total of 185 units with spon-taneus discharge were recorded.46.3%(44/95)of the neurons in AH and 23.3%(21/90)of those in PH were responsive to AS.Majority of the neurons affectedby AS exhibited a decrease in firing rate.A few units only showed transientresponse during the onset and release of AS(on-off response).Out of the 185units,85 units were tested by both AS and CO,and 15 units(17.6%)were re-sponsive to both interventions.Among them 11(73.7%)were inhibited by ASand excited by CO.From the results mentioned above,it is suggested that:(1)ASmay exert an inhibitory effect on the activity of neurons in AH.(2)The activityof neurons in PH may be also affected by AS.(3)The inputs from the atrial vo-lume receptor and carotid baroreceptor converge on the same neuron of the hy-pothalamus.