[Endogenous humoral regulators directly before an operation]

It has been shown that modern premedication techniques do not prevent the activation of the sympathoadrenal system and the enhanced synthesis of cyclic nucleotides and prostaglandin-like compounds in response to preoperative stress. In a great number of patients there are no hemodynamic shifts in the nearest preoperative period, as an increased production of prostaglandins E and cyclic nucleotides (cAMP), that is of compensatory value, is observed. When normal relations between endogenous vasoactive substances with constricting and dilating effects are damaged, a hyperdynamic reaction ensures.