Abstract
Rats with experimental cerebral ischemia were prepared by clipping bilateral carotid arteries for 30 minutes after bilateral vertebral arteries of Wistar rats had been electrocauterized. The activity of 5'-nucleotidase was measured quantitatively in brain homogenate and also demonstrated histochemically. The activity of 5'-nucleotidase was detected mainly in the pia mater and slightly in the white matter, but not in the arterial wall of Wistar rats which received a sham operation. The enzyme activity was demonstrated also in the surrounding part of cerebral arteries in rats which showed a complete paralysis brought about by the occulusion of four vessels.
The activity of 5'-nucleotidase in brain homogenate was significantly higher in rats with a complete paralysis (29.8 ± 5.2 nmoles/mg protein/min) than either in rats without paralysis (23.3 ± 3.8 nmoles/mg protein/min) or in rats with a sham operation (22.0± 4.1 nmoles/mg protein/min) (p<0.05).
These results suggest that adenosine is produced by the increased activity of 5'-nucleotidase in the periarterial region of rats with cerebral ischemia and adenosine would cause a dilatation of arteries as a compensatory mechanism for cerebral ischemia.
