Bilateral lesions of the fastigial nucleus prevent the recovery of blood pressure following hypotension induced by hemorrhage or administration of endotoxin.

The present studies were undertaken to determine if bilateral lesions of the fastigial nuclei of the cerebellum would impair the recovery and maintenance of mean arterial blood pressure during hypotension caused by hemorrhage or administration of endotoxin. We had shown previously that cerebellectomy would produce such an impairment, and the fastigial nuclei were implicated as the specific area involved due to the known pressor response observed when they are stimulated electrically. Chloralose-anesthetized dogs were made hypotensive by administration of E. coli endotoxin or hemorrhage to 50 mm Hg and observed over the subsequent 3 h. Dogs with fastigial nucleus lesions had a significantly lower mean arterial pressure during both the recovery and maintenance phases when compared with intact animals under both hypotensive protocols. In the hemorrhage study, a significant number of lesioned animals died whereas none of the controls died. Lesion of the fastigial nuclei produced an impairment similar to that seen with cerebellectomy. It is concluded that the fastigial nuclei play an important role in the recovery of blood pressure following a hypotensive episode.