Autonomic Neuroscience Centre, Royal Free Hospital, London NW3 2PF, United Kingdom.
Biol Reprod. 2006 Mar;74(3):473-80. doi: 10.1095/biolreprod.105.044602. Epub 2005 Nov 9.
The smooth-muscle cells of the testicular capsule (tunica albuginea) of man, rat, and mouse were examined by electron microscopy. They were characteristically flattened, elongated, branching cells and diffusely incorporated into the collagenous matrix and did not form a compact muscle layer. Contractile and synthetic smooth-muscle cell phenotypes were identified. Nerve varicosities in close apposition to smooth muscle were seen in human tissue. Contractions induced by adenosine 5'-triphosphate (ATP), alpha, beta-methylene ATP, noradrenaline (NA), acetylcholine (ACh), and electrical field stimulation (EFS) of autonomic nerves were investigated. Nerve-mediated responses of the rabbit and human tunica albuginea were recorded. The EFS-induced human responses were completely abolished by prazosin. In the rabbit, EFS-induced contractile responses were reduced by pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid by 36% and by prazosin by 77%. Both antagonists together almost completely abolished all EFS-induced contractions. The human tunica albuginea was contracted by NA, ATP, and alpha, beta-methylene ATP, but not by ACh. The rabbit and rat tunica albuginea were contracted by NA, ATP, alpha, beta-methylene ATP, and ACh. The mouse tunica albuginea was contracted by ACh, ATP, and alpha, beta-methylene ATP, but relaxed to NA. Immunohistochemical studies showed that P2X1 (also known as P2RX1) and P2X2 (also known as P2RX2) receptors were expressed on the smooth muscle of the rodent testicular capsule, expression being less pronounced in man. The testicular capsule of the rat, mouse, rabbit, and man all contain contractile smooth muscle. ATP, released as a cotransmitter from sympathetic nerves, can stimulate the contraction of rabbit smooth muscle. Human, rat, and mouse testicular smooth muscle demonstrated purinergic responsiveness, probably mediated through the P2X1 and/or P2X2 receptors.
采用电子显微镜观察了人类、大鼠和小鼠睾丸囊（白膜）的平滑肌细胞。这些细胞的特征是扁平、细长、分支状，并且弥散地掺入到胶原基质中，而不形成致密的肌肉层。鉴定出收缩型和合成型平滑肌细胞表型。在人类组织中观察到与平滑肌紧密相邻的神经末梢。研究了腺苷 5'-三磷酸（ATP）、α，β-亚甲基 ATP、去甲肾上腺素（NA）、乙酰胆碱（ACh）和自主神经的电刺激（EFS）诱导的收缩。记录了兔和人睾丸白膜的神经介导反应。Prazosin 完全消除了 EFS 诱导的人反应。在兔中，EFS 诱导的收缩反应被吡哆醛 6-偶氮苯-2'，4'-二磺酸减少 36%，被 Prazosin 减少 77%。两种拮抗剂一起几乎完全消除了所有 EFS 诱导的收缩。NA、ATP 和 α，β-亚甲基 ATP 使人类睾丸白膜收缩，但 ACh 则不收缩。兔和大鼠睾丸白膜受 NA、ATP、α，β-亚甲基 ATP 和 ACh 收缩。小鼠睾丸白膜受 ACh、ATP 和 α，β-亚甲基 ATP 收缩，但对 NA 则松弛。免疫组织化学研究表明，P2X1（也称为 P2RX1）和 P2X2（也称为 P2RX2）受体在啮齿动物睾丸囊的平滑肌上表达，在人类中表达程度较低。大鼠、小鼠、兔和人的睾丸囊都含有收缩型平滑肌。作为交感神经的共递质释放的 ATP 可刺激兔平滑肌的收缩。人类、大鼠和小鼠睾丸平滑肌表现出嘌呤能反应性，可能通过 P2X1 和/或 P2X2 受体介导。
