Effects of chronic selective serotonin reuptake inhibitors on 8-OH-DPAT-induced facilitation of ejaculation in rats : Comparison of fluvoxamine and paroxetine

• Published in: Psychopharmacologia Vol. 179; no. 2; pp. 509 - 515
• Main Authors: DE JONG, Trynke R, PATTIJ, Tommy, VEENING, Jan G, WALDINGER, Marcel D, COOLS, Alexander R, OLIVIER, Berend
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01.05.2005; Springer Nature B.V
• Subjects: 8-Hydroxy-2-(di-n-propylamino)tetralin - pharmacology; Animals; Biological and medical sciences; Drug toxicity and drugs side effects treatment; Ejaculation - drug effects; Female; Fluvoxamine - pharmacology; Male; Medical sciences; Paroxetine - pharmacology; Pharmacology. Drug treatments; Rats; Rats, Wistar; Serotonin Receptor Agonists - pharmacology; Serotonin Uptake Inhibitors - pharmacology; Sexual Behavior, Animal - drug effects; Toxicity: urogenital system; Antidepressant; Rat; Psychotropic; Reuptake inhibitor; Selective serotonin reuptake inhibitor; 5-HT1A Serotonine receptor; Ejaculation; Piperidine derivatives; 5-HT1A; Antidepressant agent; Facilitation; Paroxetine; Desensitization; Serotonin; Rodentia; Sexual behavior; Breeding behavior; SSRI; Vertebrata; Chemotherapy; Chronic; Mammalia; Treatment; Animal; Neurotransmitter; Fluvoxamine; Comparative study
• ISSN: 0033-3158; 1432-2072
• DOI: 10.1007/s00213-005-2186-6

Chronic treatment with selective serotonin reuptake inhibitors (SSRIs) can delay ejaculation in humans, but the extent of this effect differs between SSRIs. The involvement of 5-HT1A receptors is likely, since 5-HT1A receptor agonists accelerate ejaculation and chronic SSRI treatment is thought to desensitize 5-HT1A receptors. This study was conducted to examine the effects of chronic pretreatment with the SSRIs fluvoxamine and paroxetine on the facilitation of ejaculation induced by the 5-HT1A receptor agonist 8-OH-DPAT. Sexually experienced Wistar rats with normal ejaculatory behavior were treated for 22 days with vehicle, fluvoxamine (30 mg/kg/day), or paroxetine (10 or 20 mg/kg/day, p.o.). On day 22, rats received a challenge with saline or 8-OH-DPAT (0.4 mg/kg, s.c.). Sexual behavior was tested on days 1, 8, 15, and 22 of the SSRI-treatment. Treatment with both doses of paroxetine, but not fluvoxamine, delayed ejaculation. 8-OH-DPAT strongly accelerated ejaculation under vehicle conditions. Pretreatment with paroxetine reduced the effects of 8-OH-DPAT on ejaculation in a dose-dependent manner and more strongly than fluvoxamine. SSRIs affect 5-HT1A receptors involved in ejaculation. The degree to which this occurs, with paroxetine exerting a stronger effect than fluvoxamine, might determine the extent of SSRI-induced delayed ejaculation.