DETECTION AND QUANTITATION OF 5-HT1A AND 5-HT2A RECEPTOR MESSENGER-RNAS IN HUMAN HIPPOCAMPUS USING A REVERSE-TRANSCRIPTASE POLYMERASE CHAIN-REACTION (RT-PCR) TECHNIQUE AND THEIR CORRELATION WITH BINDING-SITE DENSITIES AND AGE

The presence and abundance of 5-HT1A and 5-HT2A receptor mRNAs in post mortem human hippocampus was investigated using a novel quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) technique usi ng cyclophilin mRNA as in internal standard. 5-HT1A and 5-HT2A recepto r mRNAs were each co-amplified with varying dilutions of cyclophilin p rimers and their abundance expressed as a ratio of cyclophilin mRNA. U sing this technique in combination with quantitative autoradiography w e have investigated the effect of aging on hippocampal 5-HT1A and 5-HT 2A receptor mRNA abundance and binding site densities. There was a sig nificant negative correlation between hippocampal 5-HT1A receptor bind ing site densities and age and a similar trend for 5-HT1A receptor mRN A abundance. Neither 5-HT2A receptor binding site densities nor mRNA a bundance were affected by age. Both 5-HT1A and 5-HT2A receptor binding site densities in individual subjects correlated significantly with a bundance of their encoding mRNA. This study demonstrates that 5-HT1A a nd 5-HT2A receptor mRNAs can be measured in small samples of human bra in. Combining studies of mRNA with those directed at binding sites wil l help reveal mechanisms underlying changes in expression of these rec eptors in various neuropsychiatric disorders.