Microinjection of acetazolamide into the fastigial nucleus augments respiratory output in the rat

Department of Physiology, University of Kentucky, Lexington, Kentucky 40536 The rostral fastigial nucleus (FNr) of the cerebellum facilitates the respiratory response to hypercapnia. We hypothesized that some FNr sites are chemosensitive to focal tissue acidosis and contribute, at least partially, to respiratory modulation. Minute ventilation ( E ) was recorded in 21 anesthetized and spontaneously breathing rats. Acetazolamide (AZ; 50 µM) was microinjected unilaterally into the FNr while an isocapnic condition was maintained throughout the experiment. AZ (1 or 20 nl) injection into the FNr significantly elevated E (46.0 ± 6.7%; P