Postmortem stability of dopamine D 1 receptor mRNA and D 1 receptors

Abstract

The effects of postmortem interval on dopamine D 1 mRNA and D 1 receptors were assessed in rat striatum under conditions simulating the handling of human brain tissue at 0, 6, 12, and 24 h postmortem. The amount of D 1 mRNA was measured by both in situ hybridization film and emulsion autoradiography with [ 35S]dATP-labeled oligonucleotide probes. D 1 receptor density was determined by autoradiography with [ 125I]SCH 23982. Neither the total amount of D 1 mRNA in the striatum nor the frequency distribution of striatal cells expressing D 1 mRNA varied with the postmortem interval. There was a modest but significant decrease (ca. 10%) in D 1 receptors over the 24 h postmortem interval; this decrease occurred within the first 6 h postmortem, with no further decreases up to 24 h postmortem. These findings suggest that the effects of postmortem interval on D 1 mRNA and receptors are minimal and should not limit an examination of possible alterations in dopamine D 1 receptor mRNA and D 1 receptors in the postmortem brains of humans with neuropsychiatric disease.