THE REACTIVITY TO NORADRENALINE OF ARTERIES OF THE HIND LEGS OF A RABBIT WHEN RUNNING, MUSCLES
In the study, we investigated the adrenergic mechanisms of regulation of blood circulation in the femoral artery of the rabbit muscle hyperemia. The method of perfusion of the region of the femoral artery by the pump constant flow when injected into the thigh artery of different doses of norepinephrine 0.5 µg /kg to 30 µg/kg according to dose-effect in double coordinates of Lineweaver – Burke determined the sensitivity of a1-adrenergic receptors and their number. Muscular hyperemia evoked by electrical stimulation of the muscles of the femur and tibia of a rabbit with a pulse frequency of 5 Hz and an amplitude of 10 volts. It was shown that when muscle hyperemia significantly reduced the pressor effect of norepinephrine at all doses in the arteries of the hind limbs of the rabbit. As a result of this study showed that muscle hyperemia caused by the electrical muscle stimulation causes dilation of the arteries due to a significant reduction of sensitivity of alpha-1-adrenergic receptors of the arteries. Found that when using low doses of norepinephrine is the difference in the reactivity of the arteries to norepinephrine in control and on the background of muscular hyperemia is more pronounced than when using an experimental high doses. Physiological analysis of ligand-receptor interactions of norepinephrine and adrenergic receptors of the arteries have shown that when muscle hyperemia sensitivity of alpha-1-adrenergic receptors of the arteries to norepinephrine decreased in 34 times. The amount of active alpha-1-adrenergic receptors of the arteries of the limb in the control and after muscle hyperemia has not changed.