Reduction in noradrenergic perivascular nerve density in the left and right cerebral arteries of old rabbits.

With the use of fluorescence and acetylcholinesterase histochemistry, marked reductions have been shown in the noradrenergic and acetylcholinesterase-positive innervation of the right ( RMC ) and left (LMC) middle cerebral arteries of old compared with young adult rabbits. The decrease in noradrenergic nerve density tended to be greater in LMC than in RMC : Nerve density fell by approximately 45% in LMC and by approximately 30% in RMC . The reductions in acetylcholinesterase-positive nerves were similar in both LMC and RMC (29 and 33%, respectively). Vessel circumference and cross-sectional wall area appeared to increase in old age in LMC and RMC .