[The mechanisms underlying the formation of systemic hemodynamic reactions: role of initial vessel tone and arterial pressure].

A review of the experimental materials describing the relationships between the initial (background) vascular tone and arterial pressure, on the one hand, and reactivity of the arterial system, on the other. Experiments were carried out on anesthetized rats under arterial hypotension caused by orthostasis or vasoactive agents, such as papaverin and sodium nitroprusside, and arterial hypertension resulting from volume expansion. It has been proposed that these relationships are based on changes in the amplitude of transmural pressure in arterial vessles.