[Experimental study on the characteristic features of sympathetic nervous system reactions in dogs with obstructive...

Possible abnormalities in the sympathetic nervous system responsible for circulatory disturbances with obstructive jaundice were investigated by determining the reactions of the heart and peripheral blood vessels using alpha.beta receptor stimulants or blockers. Mongrel dogs were randomly assigned to three groups: untreated (UT) and sham-operated (SO) controls and 3-week-old bile duct ligated (BDL). Under anesthesia with Nembutal, circulatory parameters and blood catecholamine concentration were measured. In term of alpha- and beta-adrenergic reactions, reactions in the sympathetic nervous system to alpha- and beta-receptor stimulants were examined. Mean arterial pressure (MAP) and heart rate were used as an alpha-adrenergic parameter and a beta-adrenergic parameter, respectively. The hemodynamic study in BDL group was characterized by a reduction in MAP (p less than 0.05), total peripheral resistance (p less than 0.005) and left ventricular stroke work (LVSW) (p less than 0.05) and by an increase in cardiac index (p less than 0.05). The blood norepinephrine concentration was significantly increased in jaundice (p less than 0.01). Reaction to the beta-receptor stimulant was significantly decreased in BDL group. In response to the alpha-receptor stimulant, lower reactivity was found in some animals in BDL group in comparison to SO group. Taking this into consideration with the increase in blood norepinephrine and the decrease in LVSW, the presence of abnormalities particularly in the beta-adrenergic system (receptor, cardiac muscle etc.) in jaundice is suggested to be a characteristic feature of reactions in the sympathetic nervous system. Such abnormalities are speculated to be responsible for postoperative shock.