[Age and features of the functional properties of vascular smooth muscle cells].

Studies on the electric and contractile properties of smooth muscle cells (SMC) of the portal vein of rats aged 6 to 8 months and 26 to 28 months showed that the number of spontaneously active cells, the membrane potential of SMC and action potential amplitude change with age. The force and duration of spontaneous phasic contractions of the strips of test vessels increased. The old animals had a reduction in the maximum rate of contraction and relaxation. These changes play a definite role in the mechanism of vascular tone shifts and in their function during ontogenesis.