Rat glomerulosa cells express functional 5-HT7 receptors

It has been previously demonstrated that serotonin (5-HT) is a potent stimu lator of aldosterone secretion in amphibians and mammals. The aim of the pr esent study was to characterize the type of serotonergic receptor involved in the action of 5-HT on rat glomerulosa cells. The effects of 10 serotoner gic receptor agonists and 12 receptor antagonists on aldosterone secretion from perifused rat adrenocortical slices were investigated. Correlation ana lysis between the potencies of the different compounds in our model and tho se previously reported for transfected 5-HT receptors showed that the rat a drenal 5-HT receptor exhibits the pharmacological profile of the 5-HT7 rece ptor. RT-PCR amplification with specific primers for the 5-HT7 receptor con firmed the presence of 5-HT7 receptor mRNA in the adrenal cortex. Western b lot analysis using antibodies against the 5-HT7 receptor revealed the occur rence of a protein with an apparent molecular mass of 66 kDa in the zona gl omerulosa. In glomerulosa cells, 5-HT induced a concentration-dependent inc rease of cAMP formation. These data demonstrate that rat adrenal glomerulos a cells express functional 5-HT7 receptors positively coupled to adenylyl c yclase.