Fluoxetine and sertraline effects on rat distal cauda epididymis contraction, sperm count and sperm transit time trough epididymis

Fluoxetine and sertraline are antidepressants drugs capable to impair male fertility by decreasing the number of sperm cells in the ejaculate. However, the mechanism underlying these effects is still not fully understood. It is also reported that alterations in epididymis contraction induced by different drugs affect the number of sperm cells, leading to male fertility alterations. Therefore, this study aimed to investigate if both fluoxetine and sertraline could affect the rat epididymis contraction, altering the sperm transit and/or sperm count trough rat epididymis. In vitro effects of fluoxetine and sertraline (1, 3 and 10 mu M) were evaluated in isolated distal cauda epididymis of rats by pharmacological experiments. The effects of long-term treatment with fluoxetine and sertraline (20 mg/kg, i.p., 21 days) were also checked on distal cauda epididymis contractions, serum testosterone levels, sperm production, sperm reserves and sperm transit time trough rat epididymis. In vitro fluoxetine and sertraline ( > 3 mu M) impaired the contractions induced by KCl, phenylephrine or carbachol although fluoxetine 1 mu M potentiate the phenylephrine-induced contractions. Long-term in vivo treatment with fluoxetine and sertraline promoted: (a) an enhancement of rat distal cauda spontaneous contractions; (b) a potentiation of phenylephrine-induced contractions; (c) a decreased in serum testosterone levels; and (d) a diminished daily sperm production, sperm reserves trough epididymis and sperm transit time in rat cauda epididymis. In conclusion, the alteration in the motor activity of epididymis could be associated to the low sperm count in this organ and accelerated transit time trough epididymal cauda of rats.