Bernstein Center for Computational Neuroscience Berlin, Humboldt-Universität zu Berlin, Philippstrasse 13, Haus 6, Berlin, Germany.
Institute for Integrative Neuroanatomy, Charité - Universitätsmedizin Berlin, CCM, Philippstrasse 12, 10115, Berlin, Germany.
Sci Rep. 2023 May 31;13(1):8862. doi: 10.1038/s41598-023-35030-w.
The human penis transmits behaviorally important sensory information via the dorsal penile nerve, which is required for initiation and maintenance of erection. The human penis differs from the penes of other hominids. The lack of a baculum makes the human penis dependent on erectile tissue, which is under control of neural signals activated by tactile stimulation. Accordingly, the penile sensory innervation is crucial for human sexual behavior. To clarify penile innervation, we analyzed the architecture of the dorsal penile nerve of five male subjects who donated their body. We stained the sensory fibers in the penile dorsal nerve with anti-neurofilament H antibody, and identified myelinated axons with Luxol fast blue staining. Furthermore, we visualized nerve bundles as they travel along the shaft of the penis by performing microfocus computed tomography scans after counterstaining penes with iodine. Our results show that the dorsal penile nerve is organized in 25-45 loosely packed nerve bundles, running mediodorsally in the shaft of the penis. This organization corresponds to that in penes of other mammalian species, but differs from the organization of the other peripheral sensory nerves. Around half of the dorsal penile nerve fibers were myelinated and a human hemipenis contained a total of 8290 ± 2553 (mean ± SD) axons. Thus, the number of sensory axons in the human dorsal penile nerve is higher than in other species described so far. The large fraction of unmyelinated nerve fibers suggests that the conduction speed is not a crucial aspect of penile sensory transmission.
人类阴茎通过背侧阴茎神经传递行为相关的重要感觉信息，该神经对于勃起的启动和维持是必需的。人类阴茎与其他灵长类动物的阴茎不同。缺乏阴茎骨使得人类阴茎依赖于勃起组织，而勃起组织受神经信号控制，这些信号是由触觉刺激激活的。因此，阴茎感觉神经支配对人类性行为至关重要。为了阐明阴茎神经支配，我们分析了 5 名男性捐献者尸体的阴茎背侧神经的结构。我们使用抗神经丝 H 抗体对阴茎背侧神经中的感觉纤维进行染色，并使用卢索快速蓝染色鉴定有髓轴突。此外，我们通过对阴茎进行碘反染后进行微焦点计算机断层扫描，来观察神经束在阴茎轴上的行进。我们的结果表明，背侧阴茎神经由 25-45 个松散排列的神经束组成，沿阴茎轴向中背侧行进。这种组织排列与其他哺乳动物阴茎的组织排列相对应，但与其他周围感觉神经的组织排列不同。大约一半的背侧阴茎神经纤维是有髓鞘的，一个人类阴茎包含总共 8290±2553（平均值±标准差）个轴突。因此，人类背侧阴茎神经中的感觉轴突数量高于迄今描述的其他物种。大量无髓鞘神经纤维表明，神经传导速度不是阴茎感觉传递的关键方面。
