Abstract
Using urethane-chloralose anesthetized and artificially ventilated rats, the effect of vestibular stimulation on cerebral blood flow (CBF) was investigated. CBF in the parietal cortex was measured continuously by laser Doppler flowmetry. Caloric vestibular stimulation with cold water (0°C) produced decreases of both systemic blood pressure (BP) and CBF. Electrical stimulation of vestibular nerve was performed by placing the electrode on vestibular and cochlear window. Electrical vestibular stimulation also produced decreases of BP and CBF which are intensity-dependent. In addition, chemical (L-glutamate) activation of vestibular nucleus produced a similar effect. Following spinal transection at the first thoracic level, both BP and CBF responses by electrical vestibular stimulation were abolished. It was concluded that vestibular stimulation produces a decrease in CBF and it appears to be a secondary effect of depressor response.
