Insular cortex lesions alter baroreceptor sensitivity in the urethane-anesthetized rat

Area of Science:

• Neuroscience
• Cardiovascular Physiology
• Autonomic Nervous System Regulation

Background:

• The insular cortex plays a role in cardiovascular representation.
• Lateralization of insular function in cardiovascular control is suggested but not fully understood.
• Baroreceptor gain is a key indicator of autonomic cardiovascular regulation.

Purpose of the Study:

• To investigate the role of the insular cortex in cardiovascular control.
• To determine the lateralized function of the insular cortex in baroreceptor gain regulation.
• To differentiate the roles of anterior and posterior insula in cardiovascular regulation.

Main Methods:

• Investigated baroreceptor gain using phenylephrine (PE) and sodium nitroprusside (SNP) in urethane-anesthetized rats.
• Utilized single lesion placement targeting the anterior or posterior insula (left or right) and adjacent cortex.
• Assessed changes in baroreceptor gain, heart rate, and blood pressure before and after lesioning.

Main Results:

• Lesions in the anterior insula or adjacent cortex did not significantly affect baroreceptor gain.
• Left posterior insular lesions significantly increased baroreceptor gain (p<0.0001).
• Right posterior insular lesions did not affect baroreceptor gain but increased heart rate and blood pressure (p<0.05).

Conclusions:

• The posterior insula, not the anterior insula or surrounding cortex, is primarily involved in cardiovascular control.
• The left insular cortex is predominantly involved in parasympathetic cardiac regulation.
• The right posterior insular cortex may regulate both cardiac and sympathetic vasomotor tone.