1981 Volume 3 Issue 3 Pages 302-310
In order to examine the role of noradrenergic nerve system in autoregulation of cerebral blood flow, the effect of fusaric acid (FA), inhibitor of dopamine-β-hydroxylase, on autoregulatory response of pial arteries was investigated by the vidicon camera system in 8 cats.
Before the inhibition, the pial arteries were dilated by exsanguination and constricted by reinfusion. Intravenous administration of FA (50 mg/kg) produced a significant dilation of the pial arteries and a decrease of mean arterial blood pressure (MABP). About 30 minutes after the administration, autoregulatory response of the pial arteries was re-examined. Contrary to the experiments before inhibition, pial arteries were constricted by exsanguination and dilated by reinfusion.
Cerebral vasomotor index (-Δdiameter (μ) /MABP (mmHg)) (VMI) was calculated for evaluation of the autoregulatory response of the pial arteries. Before FA administration, VMI was +0.397±0.302 in exsanguination and was +0.343±0.237 in reinfusion. But after FA administration, they changed to -0.294±0.236, -0.299±0.301 respectively (p<0.001).
These results indicated that the function of the nerve terminal of noradrenergic system has an important role in the neurogenic process of autoregulation of cerebral blood flow.
