An arterially perfused brainstem preparation of guinea pig to study central mechanisms of airway defense.

Affiliation

Florey Institute of Neuroscience and Mental Health, Gate 11 Royal Parade, 3052 Parkville, University of Melbourne Victoria, Australia; Department of Anatomy and Neuroscience, Royal parade, University of Melbourne Victoria, 3052 Parkville, Australia. Electronic address: [Email]

Abstract

The perfused working heart brainstem preparation of rodents has become a widely used tool to study brainstem function. Here, we adapt this experimental technique for newborn guinea pigs (postnatal day 7-14) to develop a tool that enables investigation of airway defense mechanisms not observed in other rodents. The perfused guinea pig brainstem preparation generates a stable eupnea-like motor pattern recorded from the phrenic, recurrent laryngeal and intercostal nerves and basic cardio-respiratory reflexes, including the arterial chemoreceptor, the baroreceptor reflex. In addition a fictive laryngeal cough reflex can be reliably elicited after mechanical stimulation of the trachea. Single unit recordings within the ponto-medullary respiratory column show robust central respiratory neuronal activity. Additionally, as in other species ponto-medullary transection of the brainstem produces apneusis. The latter suggests that the preparation fully preserves ponto-medullary synaptic connectivity that is required for eupnea-like respiratory rhythm and pattern formation and the mediation of various cardio-respiratory reflexes. We conclude that this novel research tool provides an alternative to established rat and mouse preparations and may become a experimental tool for the investigation of central mechanisms that mediate laryngeal cough.

Keywords

Airway defense,Brainstem,Cough,Hering-Breuer reflex,Pneumotaxic center,Respiratory pattern,Respiratory rhythm,