Identification of mRNA for 5-HT1 and 5-HT2 receptor subtypes in human coronary arteries.
OBJECTIVE
Although pharmacological studies have indicated that serotonin (5-HT)-evoked contraction of the human coronary artery is mediated by 5-HT1-like and 5-HT2 receptors, the gene expression of 5-HT receptors is still unclear. We examined mRNA expression of 5-HT1 and 5-HT2 receptor subtypes in human coronary arteries.


METHODS
Total RNA was extracted from human coronary arteries of 14 patients at autopsy by the guanidine method. Reverse transcription-polymerase chain reaction (RT-PCR) and ribonuclease protection assays were performed to identify 5-HT1 and 5-HT2 receptor mRNA expression in human coronary artery.


RESULTS
By RT-PCR, 5-HT1b, 5-HT2A and 5-HT2B mRNAs were detected in all of the 14 patients. 5-HT1A, 5-HT1D, and 5-HT1E mRNAs were detected in only some patients. However, neither 5-HT1F mRNA nor 5-HT2C mRNA was detected in any patient. By ribonuclease protection assay, 5-HT1B and 5-HT2A signals were detected in all patients examined, but neither 5-HT1A, 5-HT1D nor 5-HT2B signal was detected in any patient.


CONCLUSIONS
Of 5-HT1/2 receptor subtypes, 5-HT1B and 5-HT2A receptor mRNAs were predominantly expressed in human coronary arteries. Our finding provides molecular evidence that the 5-HT1B receptor may be the 5-HT1-like receptor which mediates constriction of human coronary arteries.
D000368:Aged; D003331:Coronary Vessels / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D015870:Gene Expression; D006801:Humans; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis*; D044302:Receptor, Serotonin, 5-HT1B; D044346:Receptor, Serotonin, 5-HT1D; D044402:Receptor, Serotonin, 5-HT2A; D044403:Receptor, Serotonin, 5-HT2B; D011985:Receptors, Serotonin / Q000235:genetics*; D044263:Receptors, Serotonin, 5-HT1; D020133:Reverse Transcriptase Polymerase Chain Reaction