The influence of nimodipine on cerebral and general hemodynamics in rats under condition of hypokinesia

Abstract

The aim of the study was to reveal the influence of nimodipine on cerebral and general hemodynamics at different periods of hypokinesia (HK). The gauging of parameters was carried out under general anesthesia before and at the third minute after intravenous injection of three doses of nimodipine (1, 3 and 10 microg/kg). The local cerebral blood flow (ICBF) was measured with laser-Doppler flowmetry probe placed on the parietal cortex. In the 15-day HK indices did not differ from the control group, only mean the arterial blood pressure (MABP) and resistance of cerebral vessels (CVR) were smaller when the highest dose was used. In the 30- and 45-day HK a statistically significant increase of ICBF and a decrease of CVR and MABP was observed. These changes were more expressed in the 45-day HK, and in the 60-day HK some stabilization of these parameter was noted. Most vividly expressed augmentation of HR, in comparison with the control is revealed at the dose of 10 microg/kg on the 30th day of HK. The deltaHR/deltaMABP ratio was decreased with augmentation of term of the HK, achieving its minimum by the 45th day. However, at the dose of 10 microg/kg in 60-day HK this ratio decreased even more. It has been concluded that HK was able to change the sensitivity to the cerebrovasoselective calcium channel blocker--nimodipine.