Arterial baroreceptor function in differential cardiovascular adjustments induced by central thermal stimulation

Area of Science:

• Cardiovascular Physiology
• Neuroscience
• Thermoregulation

Background:

• Baroreceptors are crucial for blood pressure regulation.
• Spinal cord stimulation can elicit cardiovascular adjustments.
• The role of baroreceptors in these adjustments is not fully understood.

Purpose of the Study:

• To investigate the role of baroreceptor signals in cardiovascular responses to spinal cord thermal stimulation.
• To compare responses in baroreceptor-denervated dogs with those in intact dogs.

Main Methods:

• Dogs underwent anesthesia, artificial ventilation, vagotomy, and carotid bifurcation denervation.
• Regional blood flow, cardiac output, heart rate, and arterial pressure were measured.
• Spinal cord was heated and cooled.
• Experiments included sympathetic blockade or removal.

Main Results:

• Spinal cord thermal stimulation induced appropriate thermoregulatory adjustments in skin blood flow.
• Heating caused cutaneous vasodilation and intestinal vasoconstriction, increasing heart rate and cardiac output.
• Cooling resulted in cutaneous and intestinal vasoconstriction.
• Blood pressure homeostasis was lost after baroreceptor denervation.

Conclusions:

• Baroreceptor signals are not primary drivers of differential vasomotor responses to spinal cord thermal stimulation.
• Baroreceptor signals significantly contribute to blood pressure homeostasis during these stimuli.