Acta physiologica Scandinavica
-
Acta Physiol. Scand. · Oct 1997
Effects of scorpion venom on central and peripheral circulatory response in an open-chest dog model.
Scorpion venom can induce in dogs severe haemodynamic changes leading to rapid rise in systemic blood pressure and cardiac output, followed by reduction of cardiac output and blood pressure within 1 h. The decrease in cardiac output is not related to myocardial dysfunction (Tarasiuk et al. 1994). We hypothesized that scorpion venom affects cardiac output by reducing venous return to the heart. ⋯ This study indicates that, in dogs, scorpion venom affects cardiac output by modifying the determinants of venous return. The initial increase in cardiac output is related to increased mean circulatory pressure since resistance to venous return did not change. The later fall in cardiac output is related to the reduction of mean circulatory pressure and increased resistance to venous return.
-
Acta Physiol. Scand. · Sep 1975
Imitation of glucagon effects on splanchnic hemodynamics and liver function by N6,2'-O-dibutyryl 3',5'-cyclic AMP (DBcAMP) in cats.
Fasting cats anesthetized with chloralose were used for the experiments. DBcAMP infused at a rate of 340 nmol/kg/min increased the gastrointestinal and intrahepatic portal conductances whereas the hepatic arterial conductance was decreased. The hemodynamic responses to portal and systemic venous administration of DBcAMP were identical. ⋯ DBcAMP infused at a rate of 850 nmol/kg/min accentuated the decrease in hepatic arterial conductanc- but was found to decrease the splanchnic ethanol elimination rate and oxygen cownsumption. Infusion of cAMP, AMP and adenosine at a rate of 340 nmol/kg/min were without measurable effects. Based on these results it is concluded that like the metabolic effects also the vascular effects of glucagon are caused by stimulation of specific glucagon receptors which results in an intracellular release of cAMP.