Chronic administration of fluoxetine impairs neurogenic and endothelium-dependent relaxation of the rabbit corpus cavernosum smooth muscle

• Published in: European journal of pharmacology Vol. 670; no. 1; pp. 224 - 228
• Main Authors: Göçmez, Semil Selcen, Utkan, Tijen, Gacar, Nejat, Sarioglu, Yusuf
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 16-11-2011; Elsevier
• Subjects: acetylcholine; agonists; Animals; antidepressants; Biological and medical sciences; Corpus cavernosum; Cyclic GMP - metabolism; Dose-Response Relationship, Drug; electric field; Electric Stimulation; Endothelium - cytology; Endothelium - drug effects; Endothelium - metabolism; Endothelium - physiology; Erectile dysfunction; Fluoxetine; Fluoxetine - administration & dosage; Fluoxetine - pharmacology; In Vitro Techniques; Male; Medical sciences; Muscle Relaxation - drug effects; Muscle, Smooth - cytology; Muscle, Smooth - drug effects; Muscle, Smooth - metabolism; Muscle, Smooth - physiology; Nervous System Physiological Phenomena - drug effects; Nitric oxide; Nitric Oxide - metabolism; nitroprusside; Penile Erection - drug effects; Penile Erection - physiology; Penis; Penis - cytology; Penis - drug effects; Penis - metabolism; Penis - physiology; Pharmacology. Drug treatments; phenylephrine; Rabbit; Rabbits; serotonin; Serotonin Uptake Inhibitors - administration & dosage; Serotonin Uptake Inhibitors - pharmacology; smooth muscle; Time Factors; Rabbit; Corpus cavernosum; Erectile dysfunction; Penis; Fluoxetine; Nitric oxide; Serotonin; Erection disorders; Psychotropic; Smooth muscle; Reuptake inhibitor; Lagomorpha; Male genital system; Selective serotonin reuptake inhibitor; Endothelium; Vertebrata; Chronic; Mammalia; Animal; Neurotransmitter; Antidepressant agent; Male genital diseases
• ISSN: 0014-2999; 1879-0712
• DOI: 10.1016/j.ejphar.2011.08.039

Antidepressants, including selective serotonin reuptake inhibitors (SSRIs), cause erectile dysfunction; however, the mechanism by which they cause erectile function is unclear. We investigated the reactivity of the corpus cavernosum after chronic fluoxetine treatment in rabbits. Twelve rabbits were randomly divided into two groups: control (n=6) or 20mg/kg/day of fluoxetine delivered i.p. (n=6). The reactivity of the corpus cavernosum tissue from the fluoxetine-treated and control groups was studied in organ chambers after 21days of fluoxetine injection. In the fluoxetine-treated group, endothelium-dependent relaxation of the corpus cavernosum in response to acetylcholine was significantly decreased compared to the control group. However, the sensitivity (i.e., pD2) of the fluoxetine-treated cavernosal tissue strips to acetylcholine was not changed with respect to controls. Electrical field stimulation (EFS)-induced neurogenic relaxation was also significantly reduced in the fluoxetine-treated group. Relaxation in response to the nitric oxide (NO) donor sodium nitroprusside was similar between the cavernosal tissues from the two groups. There was also no change in agonist potency between the two groups. Additionally, chronic fluoxetine treatment had no effect on KCl-induced contractile responses. When tissue contraction was produced with phenylephrine to study relaxation in response to various stimuli, the tension induced was similar between the fluoxetine-treated and control groups. This study suggests that chronic fluoxetine treatment causes significant functional changes to the penile erectile tissue of rabbits, and these changes may contribute to the development of impotence.