Relationship to survival of catecholamine levels and dopamine-beta-hydroxylase activity in experimental haemorrhagic shock.

Changes of plasma catecholamine levels, dopamine-beta-hydroxylase (DBH) activity and survival were studied in pentobarbital anaesthetized dogs during haemorrhagic hypotension. Shock was elicited by bleeding the animals to a mean arterial pressure of 4 kPa. This pressure was maintained until 15% of the maximum bleeding volume had been taken up spontaneously, then the remaining shed blood was reinfused. Twelve out of 28 animals died within 24 hours. Catecholamine and DBH levels were measured by radioenzymatic methods. Haemorrhagic hypotension caused a significant rise in the plasma catecholamine and DBH levels but the magnitude and time course of the rise was different. The increase of the plasma catecholamine level was higher than that of DBH activity. The highest catecholamine level was observed at the time of the maximum bleeding volume. DBH activity reached its peak during spontaneous blood re-uptake, whereas at the same time the catecholamine level decreased. These results suggest that the decrease of sympathetic activity, as represented by the decreasing catecholamine level was not followed immediately by a similar trend in DBH activity, presumably due to the delayed transport of the enzyme. Both the catecholamine and the DBH levels were significantly higher in non-surviving animals in which an extremely high level represents the stage of irreversibility of the shock.