5-HYDROXYTRYPTAMINE RECEPTOR SUBTYPE MESSENGER-RNAS IN RAT PERIPHERALSENSORY AND SYMPATHETIC-GANGLIA - A POLYMERASE CHAIN-REACTION STUDY

While serotonin has been shown to play an important role in peripheral pain mechanisms, the specific subtypes of receptors involved and thei r differential distribution between the sensory and sympathetic nervou s system remains poorly understood. In this study, the presence of mes senger RNA for rat serotonin receptor subtypes in peripheral sensory a nd sympathetic ganglia was detected using the method of polymerase cha in reaction. Lumbar dorsal root ganglia, superior cervical sympathetic ganglia and lumbar sympathetic ganglia were excised from anesthetized Sprague-Dawley rats. Oligonucleotide primers were chosen based on uni que regions of complementary DNA sequence for each of the 12 cloned ra t serotonin receptor subtypes (i.e. 5-HT1A, 5-HT1B, 5-HT1D, 5-HT1F, 5- HT2A, 5-HT2B, 5-HT2C, 5-HT3, 5-HT5A, 5-HT5B, 5-HT6 and 5-HT7) and high stringency conditions were used during polymerase chain reaction. Wit hin lumbar dorsal root ganglia, the presence of the 5-HT1B, 5-HT1D, 5- HT2A, 5-HT2C, 5-HT3 and 5-HT7 receptor subtype messenger RNAs was dete cted. Within superior cervical ganglia, the presence of messenger RNA for 5-HT1A, 5-HT1B, 5-HT1D, 5-HT2A, 5-HT3, 5-HT6, and 5-HT7 receptor s ubtypes was detected. Lumbar sympathetic ganglia displayed banding ide ntical to the superior cervical ganglia with the exception of the 5-HT 6 receptor which was not detected in the lumbar sympathetic ganglia. T he polymerase chain reaction product from each positively-detected rec eptor subtype was subcloned and sequenced and found to correspond to p ublished complementary DNA sequences. Findings from this study may dir ect further efforts to determine the role of 5-hydroxytryptamine recep tors in the peripheral nervous system.