Acetylcholinesterase Activity of Plasma and Erythrocytes during Hemorrhage in Conscious Swine

摘要

Plasma and erythrocyte acetylcholinesterase(AChE) activity changes in response to hemorrhage were studied in two groups of conscious immature swine (21 + or - 1 kg) 7 to 10 days after chronic implantation of arterial and venous catheters. One group was immobilized in a Pavlov sling, the other remained unrestrained in portable holding cages. The animals were hemorrhaged 36 ml/kg over 60 minutes and studied over another 120 minutes. Compared to unrestrained pigs, animals in the sling showed less of a decline in mean arterial blood pressure (37 + or -(-3 vs 61 + or - 11 mmHg) at the end of hemorrhage and a more marked increase in heart rate (201 + or - 17 vs 133 + or - 12 beats/min); these group differences were significant (P<0.05). In both groups hematocrit was reduced significantly to the same level, and arterial blood gases showed no differences. Erythrocyte AChE activity also showed no difference between groups or significantly change during hemorrhage. Plasma AChE activity fell significantly during hemorrhage. The between-group difference was not statistically significant. The decrease in plasma AChE activity persisted for over two hours after hemorrhage. Following hemorrhage there was a 57% reduction in total intravascular AChE activity and an 18% reduction in total plasma activity . Although immobilization altered cardiovascular variables, it did not modify AChE activity. The reduction of AChE activity following hemorrhage may increase susceptibility to anesthetic agents.