Disturbances in hormonal regulation of vascular tone during traumatic shock.

Changes in hormonal regulation of the vascular tone in Wistar rats were studied on Cannon model of traumatic shock. The pressor response to angiotensin II decreased by 30-40% 3 h after the incidence of trauma. The reaction to vasopressin remained unchanged. However, phenylephrine in medium and high doses produced a more pronounced pressor response under these conditions. One day after trauma we revealed a decrease in vascular sensitivity not only to angiotensin II, but also to vasopressin and alpha1-adrenoceptor agonist phenylephrine. The vascular response was observed only after treatment with phenylephrine in maximum doses. Traumatic shock was accompanied by inverse response to serotonin: hypertensive effect instead of blood pressure drop. Our results show that traumatic shock is accompanied by specific changes in vascular reactivity.