Urethane and vagotomy reshape cardiorespiratory homeostasis and RTN chemoreceptor function

Area of Science:

• Neurophysiology
• Cardiorespiratory Physiology
• Homeostasis

Background:

• Urethane anesthesia and vagotomy are common in neurophysiology.
• Their impact on physiological homeostasis is not fully defined.

Purpose of the Study:

• To assess the effects of urethane anesthesia and vagotomy on arterial blood gases and cardiorespiratory parameters in rats.
• To investigate the activity of retrotrapezoid nucleus (RTN) chemoreceptor neurons under these conditions.

Main Methods:

• Rats were subjected to urethane anesthesia and/or bilateral vagotomy.
• Arterial blood gases (PaCO2, PaO2, pH) and cardiorespiratory parameters (HR, MAP, fR, VT, VE) were measured.
• Activity of RTN chemoreceptor neurons was studied.

Main Results:

• Urethane anesthesia decreased MAP, VT, VE, and PaO2, while increasing HR, fR, and PaCO2.
• Vagotomy further increased MAP, HR, VT, and aggravated hypercapnia and acidosis.
• Vagotomy altered RTN neuronal activity, abolishing phasic inhibition and reducing CO2 thresholds.

Conclusions:

• Urethane anesthesia and vagotomy profoundly alter cardiorespiratory parameters and physiological homeostasis.
• Vagal inputs dynamically modulate RTN neuronal activity and central respiratory control.
• Vagal feedback is essential for maintaining normal cardiorespiratory function.