Kozyrev Natalie, Staudt Michael D, Brown Arthur, Coolen Lique M
1 Department of Anatomy and Cell Biology, Western University , London, Ontario, Canada .
2 Department of Physiology, University of Michigan , Ann Arbor, Michigan.
J Neurotrauma. 2016 May 15;33(10):943-53. doi: 10.1089/neu.2015.4232. Epub 2016 Jan 15.
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.
慢性脊髓损伤（SCI）会导致男性射精功能严重紊乱。射精是一种反射，大鼠射精反射的脊髓发生器位于腰骶部脊髓。SCI对大鼠脊髓射精发生器和射精反射的影响仍未得到充分研究。本研究的首要目标是确定慢性SCI对脊髓射精发生器功能的影响。雄性大鼠在T6 - T7脊髓水平接受挫伤性损伤。在SCI后4 - 6周，对受伤大鼠和对照大鼠进行电刺激阴茎背神经（DPN）引发的射精反射评估。在DPN刺激后，SCI雄性大鼠球海绵体肌（BCM）的爆发活动（射精排出阶段的指标）以及精囊压力（SVP）的增加（射精射出阶段的指标）均显著降低。因此，挫伤性SCI导致射精反射长期受损。D3激动剂7 - 羟基 - 2 - （二 - N - 丙基氨基）四氢萘（7OHDPAT）可促进脊髓完整大鼠的射精，因此本研究的第二个目标是测试皮下输注7OHDPAT是否能促进慢性SCI大鼠的射精反射。雄性大鼠在T6 - T7接受挫伤性损伤，并在损伤后4 - 5周测试全身给予7OHDPAT（1 mg/kg）的效果。结果显示，在评估反射之前，只要通过横断切断腰髓的脊髓上输入，给予7OHDPAT就能促进有或无DPN刺激的SCI雄性大鼠的射精反射。因此，对SCI雄性大鼠给予7OHDPAT能够克服SCI对射精反射的有害影响。
