Plasma dopamine-beta-hydroxylase and platelet monoamine oxidase activities in pigs with different susceptibility to the malignant hyperthermia syndrome by halothane.

Plasma DBH and platelet MAO activities were measured by radioenzymatic assay in 10 Large-White and 20 Piétrain pigs 9 to 11 weeks old. Piétrain pigs within the same litter, challenged by halothane, were classified as malignant hyperthermia (MH) susceptible or not according to their reaction. The Large-White pig strain was not susceptible to MH. Plasma DBH activity did not differ according to strain or to MH susceptibility. Platelet MAO was lower in Large-White pigs but was not affected by MH susceptibility in Piétrain pigs. The results do not confirm any nervous differences in MH-susceptible pigs.