title: Chronic Contusion Spinal Cord Injury Impairs Ejaculatory Reflexes in Male Rats: Partial Recovery by Systemic Infusions of Dopamine D3 Receptor Agonist 7OHDPAT.
abstract: Chronic spinal cord injury (SCI) causes major disruption of ejaculatory function in men. Ejaculation is a reflex and the spinal generator for ejaculatory reflexes in the rat has been located in the lumbosacral spinal cord. The effects of SCI on the rat spinal ejaculation generator and ejaculatory reflexes remain understudied. The first goal of the current study was to establish the effects of chronic SCI on the function of the spinal ejaculation generator. Male rats received a contusion injury of the spinal cord at spinal level T6-T7. Ejaculatory reflexes elicited by electrical stimulation of the dorsal penile nerve (DPN) were evaluated in injured and control rats at 4-6 weeks following SCI. SCI males demonstrated significant reductions in bursting of the bulbocavernosus muscle (BCM), an indicator for expulsion phase of ejaculation, and in seminal vesicle pressure (SVP) increases, an indicator for the emission phase of ejaculation, following DPN stimulation. Thus, contusion SCI resulted in long-term impairment of ejaculatory reflexes. The D3 agonist 7-hydroxy-2-(di-N-propylamino) tetralin (7OHDPAT) facilitates ejaculation in spinal cord intact rats, thus the second goal of the current study was to test whether subcutaneous infusions of 7OHDPAT can facilitate ejaculatory reflexes in rats with chronic SCI. Male rats received a contusion injury at T6-T7 and effects of systemic administration of 7OHDPAT (1 mg/kg) were tested 4-5 weeks following injury. Results showed that 7OHDPAT administration facilitated ejaculatory reflexes in SCI males with or without DPN stimulation, provided that supraspinal inputs to the lumbar cord were severed by transection just prior to evaluating the reflex. Thus, 7OHDPAT administration in SCI males was able to overcome the detrimental effects of SCI on ejaculatory reflexes.
authors.affiliation: 1 Department of Anatomy and Cell Biology, Western University , London, Ontario, Canada .|2 Department of Physiology, University of Michigan , Ann Arbor, Michigan.
authors.forename: Natalie
authors.initials: N
authors.lastname: Kozyrev
authors.affiliation: 1 Department of Anatomy and Cell Biology, Western University , London, Ontario, Canada .
authors.forename: Michael D
authors.initials: MD
authors.lastname: Staudt
authors.affiliation: 1 Department of Anatomy and Cell Biology, Western University , London, Ontario, Canada .|3 Robarts Research Institute, Western University , London, Ontario, Canada .
authors.forename: Arthur
authors.initials: A
authors.lastname: Brown
authors.affiliation: 1 Department of Anatomy and Cell Biology, Western University , London, Ontario, Canada .|2 Department of Physiology, University of Michigan , Ann Arbor, Michigan.|4 Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center , Jackson, Mississippi.|5 Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, Mississippi.
authors.forename: Lique M
authors.initials: LM
authors.lastname: Coolen
mesh_terms: D000818:Animals; D002908:Chronic Disease; D004195:Disease Models, Animal; D018491:Dopamine Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D004542:Ejaculation / Q000187:drug effects / Q000502:physiology*; D004558:Electric Stimulation; D008297:Male; D010413:Penis / Q000294:innervation; D060525:Pudendal Nerve / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D050637:Receptors, Dopamine D3 / Q000819:agonists*; D020127:Recovery of Function / Q000187:drug effects / Q000502:physiology*; D012018:Reflex / Q000187:drug effects / Q000502:physiology*; D012735:Sexual Dysfunction, Physiological / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000150:complications / Q000503:physiopathology*; D013764:Tetrahydronaphthalenes / Q000008:administration & dosage / Q000494:pharmacology*; D013904:Thoracic Vertebrae / Q000293:injuries
chemical_list: D018491:Dopamine Agonists; D050637:Receptors, Dopamine D3; D013764:Tetrahydronaphthalenes; C031349:7-hydroxy-2-N,N-dipropylaminotetralin
keywords: neuroplasticity; sensory function; spinal cord injury; traumatic spinal cord injury