Breathing pattern in anesthetized chickens: CO2 inhalation and vagotomy

Area of Science:

• Comparative physiology
• Avian respiratory system
• Neuroscience

Background:

• Intrapulmonary chemoreceptors (IPC) play a role in regulating avian respiration.
• Vagotomy, the surgical removal of the vagus nerves, also impacts respiratory control.

Purpose of the Study:

• To investigate the distinct effects of intrapulmonary chemoreceptor (IPC) suppression and vagotomy on chicken breathing patterns.
• To determine if IPC input is the sole driver of respiratory changes post-vagotomy.

Main Methods:

• Studied breathing patterns in 20 anesthetized chickens.
• Progressively suppressed IPC function using varying CO2 concentrations.
• Performed bilateral vagotomy and observed subsequent breathing patterns.

Main Results:

• CO2 inhalation induced specific breathing pattern changes.
• Bilateral vagotomy resulted in a distinct pattern with accentuated expiratory times and prolonged expiratory pauses.
• The vagotomy-induced pattern differed significantly from the CO2-induced pattern.

Conclusions:

• Neural input from IPC is not solely responsible for the altered breathing pattern observed after vagotomy in birds.
• Both IPC and vagal pathways contribute to respiratory control in chickens, with distinct roles.