[Hyperemia in capillaries of the gastrocnemius muscle following stretching].

Microcine-tv-study of the isolated m. gastrocnemius' capillaries in 9 anesthetized cats determined the blood flow mean velocity as 0.73 +/- 0.12 mm/s with a considerable dispersion for 216 capillaries (variation coefficient = 120-160%). The temporal dispersion of velocities in a single capillary was insignificant (variation coefficient about 45%). Longitudinal stretch of the muscle for 1-2 cm decelerated the capillary blood flow up to its complete arrest. After 1-min stretch, the blood flow velocity increased by 0.30 +/- 0.06 mm/s in 148 capillaries; decreased by 0.22 +/- 0.07 mm/s in 35 capillaries and remained the same in 5 capillaries. Apart from this, 4 capillaries initially invisible, became apparent. Average data for capillaries corresponded to those of macro-experiments. Responses of individual capillaries seem to be unrelated to initial velocity of their location within the net, if only absolute values of velocities are to be analysed.