Whether
nimodipine improves cerebral blood flow (CBF) and metabolism in
cerebral ischemia remains a controversial issue. We investigated the effect of
nimodipine on CBF, brain energy metabolism, using a
laser-Doppler
flowmeter and in vivo 31phosphorus nuclear magnetic resonance (31P NMR) spectroscopy, and blood rheology during forebrain
ischemia and reperfusion in gerbils. Eighty-three adult gerbils received
nimodipine (1 micrograms/kg/min), or an equal volume of the vehicle, or saline, over 60 min prior to a transient forebrain
ischemia for 60 min. We measured sequential changes in
phosphocreatine (PCr) /
inorganic phosphate (Pi) ratio, beta-
ATP/Pi ratio, and intracellular pH (pHi) during
ischemia and reperfusion by 31P NMR spectroscopy, and the measurement of whole blood viscosity (WBV) at 60 min after reperfusion. CBF was measured continuously throughout the study by a
laser-Doppler
flowmeter. During forebrain
ischemia, PCr/Pi and beta-
ATP/Pi ratios were higher significantly in the
nimodipine-treated group (p < 0.05 and 0.01) than in the vehicle- or saline-treated groups. During reperfusion, PCr/Pi and beta-
ATP/Pi ratios recovered significantly only in the
nimodipine-treated group (p < 0.05 and 0.01). The WBV at high shear rate (562.5 s-1) lowered significantly in the
nimodipine-treated group (p < 0.05) compared with the vehicle- or saline-treated group. CBF was higher significantly only during administration of
nimodipine in the
nimodipine-treated group (p < 0.01) than other groups.
Nimodipine improved brain energy metabolism and blood rheology during forebrain
ischemia and reperfusion in the gerbil brain.