Contractile Effects of Serotonin (5-HT) in the Rat Cauda Epididymis: Expression and Functional Characterization of 5-HT Receptors

Autor(es)

Mueller, Andre ^[1] ; Kiguti, Luiz R. A. ^[1] ; Silva, Erick J. R. ^[1] ; Pupo, Andre S. ^[1]

Afiliação do(s) autor(es)

^[1] Sao Paulo State Univ, Inst Biosci, Dept Pharmacol, Botucatu, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Pharmacology and Experimental Therapeutics; v. 369, n. 1, p. 98-106, APR 1 2019.
• Citações Web of Science: 0

Resumo

Serotonin {[}5-hydroxytryptamine (5-HT)] exerts multiple central and peripheral functions. High concentrations of 5-HT have been found in the epididymis, a ductal organ that plays pivotal roles in sperm transport and maturation. The contraction of the epididymal smooth muscle is essential for sperm transport and emission during ejaculation. The contributions of the epididymal 5-HT system to these events are poorly understood. Here, we assessed the contractile function of 5-HT in the rat cauda epididymis (CE), pharmacologically targeting the receptor(s) and the reuptake mechanism involved in this system. Segments of CE duct from adult Wistar rats were set up in an organ bath system for isometric tension recordings, and concentration-response curves to 5-HT and norepinephrine were obtained. 5-HT elicited concentration-dependent contractions of the CE duct (pEC(50) = 6.5 +/- 0.1) that were potentiated with high potency by the norepinephrine transporter (NET) inhibitor desipramine and with low potency by the highly selective serotonin transporter inhibitor paroxetine, indicating that the NET is the major mediator of 5-HT reuptake in vitro. CE contractions to 5-HT were antagonized by the alpha(1)-adrenoceptor (alpha(1)-AR) antagonist prazosin (pA(2) congruent to 8.9), 5-HT2A/2C antagonists ketanserin (pA(2) congruent to 9.4) and fluoxetine (pA(2) congruent to 7.4), and 5-HT1A ligands WAY 100635 (pA(2) congruent to 8.9) and buspirone (pA(2) congruent to 7.3). Reverse transcriptase polymerase chain reaction analysis demonstrated that 5-HT1A and 5-HT2A transcripts are highly abundant in the cauda epididymis, whereas 5-HT2c transcript was not found. Altogether, our results reveal that contractions of the CE duct to 5-HT encompasses at least activation of alpha(1)-ARs and 5-HT1A and 5-HT2A receptors, providing new insights into the roles of 5-HT on the epididymal function. (AU)

• Processo FAPESP: 17/15175-1 - Modulação da guanilato ciclase solúvel e dos níveis intracelulares de nucleotídeos cíclicos em órgãos do trato urinário inferior e próstata
• Beneficiário: Edson Antunes
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 15/08227-0 - Estudo da EPPIN como macromolécula-alvo para contracepção masculina: desenvolvimento de modelo animal para avaliar a eficácia de fármacos contraceptivos masculinos
• Beneficiário: Erick José Ramo da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores