Time-dependent effect of sectioning carotid sinus nerves on the vagally mediated baroreflex
Tóm tắt
The purpose of the reported experiments was to examine whether the vagally mediated baroreflex system (V-system) increases its feedback gain with time after sectioning of the carotid sinus nerves (CSN). In 10 dogs anesthetized with Nembutal, we determined the overall open-loop gain (G) of the rapidly acting arterial pressure control system. G was assessed as (ΔAPI/ΔAPS)-1, where ΔAPI and ΔAPS represent the immediate and steady-state decreases in arterial pressure at the aortic arch following a fast step-wise reduction in blood volume. ΔAPI, ΔAPS and GINTACT in the intact condition (30th min before sectioning of the CSN) were −1.8±0.1 kPa, −0.20±0.01 kPa and 8.4±0.3 (mean±SE), respectively. The mean values of ΔAPI, ΔAPS and G after sectioning of the CSN (GV), first averaged within individual dogs and then averaged for ten dogs, were −2.53±0.07 kPa, −1.1±0.05 kPa, and 1.5±0.1, respectively. GV did not change with time over about 4 h after sectioning of the CSN. It is concluded that the V-system cannot augment its ability to restore arterial pressure in compensation for the lost function of the carotid sinus baroreflex system over 4 h after sectioning of the CSN in the anesthetized dog.
Tài liệu tham khảo
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