Age-related changes in D1 and D2 receptor mRNA expression in postmortem human putamen with and without multiple small...

Expression of messenger RNAs (mRNAs) encoding the D1 and D2 dopamine receptors as a function of age was determined in the human putamen using the reverse transcription-polymerase chain reaction (RT-PCR). In cases without multiple small infarcts (status lacunaris) in the putamen, D1 mRNA expression was unaltered, while D2 mRNA expression significantly decreased with age. Both D1 and D2 mRNA expression was lower in cases with status lacunaris. The reduction in D1 receptors primarily located on striatonigral neurons or D2 receptors primarily located on striatopallidal neurons may inhibit thalamocortical neurons. The decreased transcription of D1 and D2 receptor genes may in part account for increased susceptibility to hypokinetic disorders in the elderly.