Barodenervation in conscious rats eliminated the bradycardia and cardiac output reduction seen with 10% CO2 and caused a marked fall in blood pressure and total peripheral resistance during hypoxia.
Does barodenervation alter cardiovascular responses to acute hypoxia and hypercapnia in conscious rats?
The arterial baroreflex is an important component of the overall cardiovascular responses to both hypercapnic and hypoxic stimuli in the conscious rat.
Experiments were performed to examine the role of the arterial baroreceptors in the cardiovascular responses to acute hypoxia and hypercapnia in conscious rats chronically instrumented to monitor systemic hemodynamics. One group of rats remained intact, whereas a second group was barodenervated. Both groups of rats retained arterial chemoreceptive function as demonstrated by augmented ventilation in response to hypoxia. The cardiovascular effects to varying inspired levels of O2 and CO2 were examined and compared between intact and barodenervated rats. No differences between groups were noted in response to mild hypercapnia (5% CO2); however, the bradycardia and reduction in cardiac output observed in intact rats breathing 10% CO2 were eliminated by barodenervation. In addition, hypocapnic hypoxia caused a marked fall in blood pressure and total peripheral resistance (TPR) in barodenervated rats compared with controls. Similar differences in TPR were observed between the groups in response to isocapnic and hypercapnic hypoxia as well. It is concluded that the arterial baroreflex is an important component of the overall cardiovascular responses to both hypercapnic and hypoxic stimuli in the conscious rat.
Walker et al. (Thu,) conducted a other in Cardiovascular responses to hypoxia and hypercapnia. Barodenervation vs. Intact rats was evaluated on Cardiovascular responses (blood pressure, total peripheral resistance, heart rate, cardiac output) to varying inspired levels of O2 and CO2. Barodenervation in conscious rats eliminated the bradycardia and cardiac output reduction seen with 10% CO2 and caused a marked fall in blood pressure and total peripheral resistance during hypoxia.