Pontine lesions produce apneusis in the rat.

Although lesion experiments in the vagotomized cat have indicated that neurons in the parabrachial region of the dorsolateral pons contribute to the mechanisms involved in terminating inspiration, a similar role for pontine structures in the rat has been questioned since pontomedullary transections in the anesthetized rat failed to prolong inspiration. In the present study, lesions of the parabrachial pons of the decerebrate, unanesthetized rat produced an increase in the duration of inspiration to 400% of control and a doubling of the duration of expiration, suggesting a role for this pontine area in the regulation of the timing of the phases of respiration.