A preliminary study on cerebellar acetylcholine-mediated blood pressure regulation in young and old rats.

Cholinergic innervation of the cerebellar cortex can modulate cerebellar functions. However, the role of acetylcholine (ACh) in cerebellar regulation of blood pressure (BP) has not been examined. Moreover, the effect of aging on this regulation remains unexplored. In this study, carotid arterial pressure was measured in young (2 months) and old (16-20 months) rats after ACh was microinjected into the cerebellar cortex. The results show a concentration-dependent effect of ACh (30, 100, and 300 mM) on mean arterial pressure (MAP), maximal decreased MAP (MDMAP) and reactive time (all Ps < 0.05). However, responses in the old animals were significantly attenuated compared to the young (Ps < 0.05). The results indicate that cerebellar cholinergic innervation exerts depressor effects on BP regulation, and such effects undergo retrogression with aging. Further studies concerning the mechanism are needed to confirm these preliminary findings.