Postmortem Changes in Brain Catecholamine Enzymes

Abstract
Postmortem changes in the activities of tyrosine hydroxylase, dopa decarboxylase, and dopamine-β-hydroxylase were examined in various areas of rat brain. Tyrosine hydroxylase activity decreased in an exponential fashion with a half-time of two to four hours in caudate-putamen, substantia nigra, and locus ceruleus. Dopa decarboxylase activity remained within 20% of control values at five hours in these areas, but then decreased precipitously. Dopamine-β-hydroxylase activity remained within 20% of control for at least 20 hours after death.