Sexual experience and plasma testosterone levels in male veterans after spinal cord injury

Fifty men with spinal cord injuries (SCI) were asked to complete a questionnaire concerning their sexuality before and after injury. Medical examination confirmed the location and completeness of the injury and extracted information about genitourologic status. The respondents rated sexuality highly as a concern in living, and a wide variety of sexual techniques were reported. A marked decrease in sexual activity, satisfaction, and feelings of sexual adequacy was reported after injury, as compared to retrospective "before injury" responses, lack of opportunity being reported as causative by 66% of the subjects and insufficient personal satisfaction by 59%. Seventy-five percent of the subjects experienced sexual arousal from genital stimulation, and several methods of eliciting erection were cited. Orgasm was described by a variety of terms. Significant differences were found between quadriplegic and paraplegic patients in answers to several items, though there was generally no difference between cervical and thoracic groups, which were more specifically broken down with respect to motor or sensory/complete or incomplete lesions. Plasma testosterone levels were found to fall well within the normal adult male range, as were levels of free testosterone and serum sex binding protein. The resulting information demonstrated more sexual concern among men with SCI than the literature previously indicated.

Effects of a potent dopamine receptor agonist, RDS-127, on penile reflexes and seminal emission in intact and spinally transected rats

Administration of RDS-127 (3.0 mg/kg) induced seminal emission within three minutes of IP injection and suppressed the display of penile reflexes in intact and spinally transected rats. In Experiment 1, RDS-127 was administered to intact, sexually experienced rats in a protocol previously demonstrated to selectively lower the ejaculatory threshold of copulating animals. The incidence of seminal emission was significantly elevated by RDS-127 but penile reflexes were present in only 8% of the drug-treated rats, compared to 59% of controls. In Experiment 2, seminal emission was induced 2.3 +/- 0.4 (S.E.) minutes from injection of RDS-127. Animals which responded to RDS-127 with multiple emissions had significantly lower ejaculation latencies during copulatory tests conducted prior to drug treatment than animals which had no or only single seminal emissions following RDS-127 injection. Spontaneous seminal emission in the 3 day period initiated 2 hours after RDS-127 injection was unaffected by the drug. Spontaneously produced plugs were approximately twice the weight of those induced by RDS-127. In Experiment 3, seminal emission was induced in spinally transected rats 1.7 +/- 0.4 minutes following RDS-127 administration, whereas drug treatment attenuated the enhancement of penile reflexes observed following midthoracic spinal transection. These experiments suggest that a spinally-mediated dopaminergic mechanism is capable of stimulating seminal emission acutely in the rat and inhibiting the display of penile reflexes by the supine animal.

Effects of a novel dopamine-receptor agonist RDS-127 (2-N,N-di-n-propylamino-4,7-dimethoxyindane), on hormone levels and sexual behavior in the male rat

Selective changes in the mating pattern occurred 30 minutes following administration of RDS-127 (3.0 mg/kg, IP) to sexually experienced adult male rats. Marked decreases in intromission frequency and ejaculation latency were observed. These data indicate a potent effect upon conummatory mechanisms underlying copulatory behavior. The lack of effect upon arousal state was further demonstrated utilizing a "mounting test" (in which the penis is anesthetized by topical application of tetracaine hydrochloride). No difference in mounting behavior was seen. Seminal plugs were noted in a large percentage of treated animals at the time of anesthetic application. Additionally, a six-fold decrease in plasma prolactin and a lesser decrement in plasma luteinizing hormone were evident. Finally, in sexually experienced castrate animals, RDS-127 induced mounting in two thirds and intromissive and ejaculatory patterns in one third of the treated animals, 35 days postcastration. These effects were greatly attenuated by 56 days postcastration. The selective alteration of consummatory mechanisms, with little or no effect upon arousal status, suggests a neurochemical separation of these two components in the intact male rat.