[The histochemical characteristics of the capillary bed of the brain in exposure to low-intensity laser radiation].

Rat brain was exposed to He-Ne laser at wavelength 632.8 nm, power density 0.76 mWt/cm2. Hippocampal capillaries detected by alkaline phosphatase were examined in various periods (from 1 sec to 3 h) after the exposure. Changes of the enzyme activity in capillary walls, capillary length and diameter were examined after laser exposures of various duration. Enzymic activity and total capillary length were found to increase within the first 15 min of irradiation by 1.5-2 times. A longer irradiation resulted in reduction of these parameters. Capillary diameter changed negligibly after 15-min exposure, and after a longer irradiation a stable dilatation of capillaries was observed.