Tea et al 2025 - data summary

This data set was generated to address a knowledge gap concerning the types of serotonin receptors involved in serotonergic activation of the hypothalamic-pituitary-interrenal (HPI) axis in fishes. Activation of the HPI axis leads to production of the glucocorticoid stress hormone, cortisol. Using rainbow trout (<i>Oncorhynchus mykiss</i>) as our study species, we detected <i>5htr1a</i>, <i>5htr2</i> and <i>5htr4</i> transcripts in all three tissues of the HPI axis by real-time RT-PCR. Administration of serotonin <i>in vivo</i> to cannulated rainbow trout evoked a cortisol response, although in the absence of an increase in <i>crf</i> transcript abundance or circulating ACTH. Recognizing that the HPI axis tissues are complex, we used an <i>in vitro</i> head kidney preparation to more fully explore the role of serotonin receptors in cortisol production by interrenal cells. Our data suggest that of the three receptor types we investigated, only 5-HT₄ receptors stimulate cortisol production.