Delayed testosterone replacement restores nitric oxide synthase-containing nerve fibres and the erectile response in rat penis
Delayed testosterone replacement restores nitric oxide synthase-containing nerve fibres and the erectile response in rat penis
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DOI：
10.1046/j.1464-410x.2000.00598.x
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发表时间：
2000-05-01
影响因子：
4.5
通讯作者：
Iwamoto, T
中科院分区：
文献类型：
--
作者：
Baba, K;Yajima, M;Iwamoto, T
目的 阐明睾酮对阴茎神经支配的影响。
材料与方法 将18只大鼠分为3组，每组6只；其中两组（1组和2组）行去势手术，第三组（3组）行假手术作为对照。去势8周后，2组大鼠皮下注射睾酮。1组和3组大鼠在8周时进行最终功能分析，2组大鼠在12周时进行。评估包括皮下注射阿扑吗啡以研究中枢介导的勃起，以及海绵体神经电刺激和罂粟碱注射以研究外周介导的勃起。处死时取阴茎中段标本进行NADPH - 黄递酶染色。
结果 在阿扑吗啡研究中，去势组的打哈欠次数和勃起次数明显少于对照组，2组的中枢勃起功能明显优于对照组。去势大鼠海绵体和双侧背神经中含一氧化氮合酶（NOS）的神经纤维平均（标准误）数量分别为46.2（9.1）和203（32.1），明显低于2组的84.1（11.2）和300.6（17.1），也低于对照组的88.6（10.9）和306.3（22.9）。在无睾酮的情况下，电刺激和海绵体内注射罂粟碱后，海绵体内压均显著降低。然而，在含NOS的神经纤维数量以及外周勃起功能研究方面，对照组和2组大鼠之间无差异。
结论 睾酮作用于神经系统以介导勃起；当睾酮缺乏时，一氧化氮（NO）的产生和活性可能均下调，从而降低通过NO途径对外周刺激的反应。2组大鼠勃起功能的恢复支持了这一现象。延迟睾酮替代对去势后勃起机制的恢复无不良影响。
Objective To elucidate the effect of testosterone on penile innervation.Materials and methods Three groups of six rats each were assessed; two groups (1 and 2) were castrated and the third (group 3) underwent a sham operation (control). Eight weeks after castration, group 2 received a subcutaneous injection with testosterone. At 8 weeks, the rats in group 1 and 3 underwent a final functional analysis while those in group 2 did so at 12 weeks. The evaluation included a subcutaneous injection with apomorphine to study centrally mediated erection, and cavernosal nerve electrostimulation and papaverine injection to study peripherally mediated erection. At death a penile mid-shaft specimen was taken for NADPH-diaphorase staining.Results In the apomorphine study, castration resulted in significantly fewer yawns and erections than in the control, and those in group 2 significantly better central erectile function than in the controls. The mean (sem) number of nitric oxide synthase (NOS)-containing nerve fibres in the corpora cavernosa and both dorsal nerves of castrated rats, at 46.2 (9.1) and 203 (32.1), respectively, were significantly lower than in rats in group 2, at 84.1 (11.2) and 300.6 (17.1), and than in the controls, at 88.6 (10.9) and 306.3 (22.9), respectively. The intracavernosal pressure decreased significantly in the absence of testosterone, both after electrostimulation and intracavernosal papaverine injection. However, there was no difference between the control and group 2 rats in either the number of NOS-containing nerve fibres or in the peripheral erectile functional study.Conclusions Testosterone acts on the nervous system to mediate erection; when it is absent there may be down-regulation of both the production and activity of NO, thereby decreasing the response to peripheral stimulation via the NO pathway. The restoration of erectile function seen in rats in group 2 supports this phenomenon. Delayed testosterone replacement has no detrimental effect on the restoration of the erectile mechanism after castration.