Htr1f, also known as the serotonin 1F receptor gene, is a crucial part of the serotonin (5-hydroxytryptamine, 5-HT) signaling system. The 5-HT signaling system is involved in various physiological functions such as cognition, reward, learning, memory, and vasoconstriction in vertebrates [2]. Htr1f belongs to the G-protein coupled receptor family and is capable of binding natural ligands (5-HT) or selective agonists like LY344864, which in turn can inhibit intracellular cAMP production and stimulate the MAPK/ERK signaling cascade [2].

In chickens, Htr1f is primarily expressed in various brain regions and the pituitary. Activation of Htr1f in cultured chicken pituitary cells can significantly inhibit the secretion of PRL stimulated by vasoactive intestinal peptide (VIP) or forskolin, suggesting its involvement in prolactin release [2]. In dairy calves, supplementation with 5-hydroxytryptophan downregulated pancreatic Htr1f mRNA and insulin-related proteins, indicating its role in glucose and insulin metabolism [3]. In human migraine studies, the Htr1f locus was identified as a risk locus for migraine, suggesting its association with migraine pathophysiology [1].

In conclusion, Htr1f plays important roles in multiple biological processes, including hormone regulation in chickens, glucose and insulin metabolism in dairy calves, and is associated with migraine in humans. The study of Htr1f through different animal models and human genetic analyses helps to understand its functions in various physiological and disease-related conditions, providing potential insights for treating related diseases.

References:

1. Hautakangas, Heidi, Winsvold, Bendik S, Ruotsalainen, Sanni E, Palotie, Aarno, Pirinen, Matti. 2022. Genome-wide analysis of 102,084 migraine cases identifies 123 risk loci and subtype-specific risk alleles. In Nature genetics, 54, 152-160. doi:10.1038/s41588-021-00990-0. https://pubmed.ncbi.nlm.nih.gov/35115687/

2. Sun, Caiyun, Qiu, Yang, Ren, Qin, Zhang, Jiannan, Wang, Yajun. 2021. Molecular Cloning and Functional Characterization of Three 5-HT Receptor Genes (HTR1B, HTR1E, and HTR1F) in Chickens. In Genes, 12, . doi:10.3390/genes12060891. https://pubmed.ncbi.nlm.nih.gov/34207786/

3. Field, S L, Marrero, M G, Dado-Senn, B, Scheffler, T L, Laporta, J. 2020. Peripheral serotonin regulates glucose and insulin metabolism in Holstein dairy calves. In Domestic animal endocrinology, 74, 106519. doi:10.1016/j.domaniend.2020.106519. https://pubmed.ncbi.nlm.nih.gov/32739765/