Liu S P, Horan P, Levin R M
Department of Biological Science, Albany College of Pharmacy, NY 12208, USA.
Pharmacology. 1998 Apr;56(4):216-22. doi: 10.1159/000028200.
Regulation of corporal smooth muscle tone is essential for the initiation of penile erection. In recent years, in vitro isometric tension studies using isolated corpus cavernosal tissue have been used extensively to investigate the mechanisms regulating corporal smooth muscle tone and tension. In the present study, we utilized digital analysis of contractile data generated from investigation of contractile and relaxation responses of isolated rabbit corpus cavenosum to various forms of stimulation. Digital analysis of the contractile and relaxation data allows quantitation of both maximal and mean rates of tension change, and time elapsed to maximal response. Rates of tension changes may provide additional important information regarding cellular events that mediate corporal tone and tension changes.
Sexually mature male New Zealand White rabbits were used. Each corpus cavernosum was dissected sharply from the removed penis, then two longitudinal strips were prepared for isometric tension studies and placed in individual baths. Tension was monitored continually using an 8-channel Grass Polygraph. The Grass PolyVIEW system simultaneously converted analog signals to digital information and stored data using a 486 PC computer. Each corporal strip was prestimulated with 300 mumol/l phenylephrine to produce a maximal contraction, then field stimulation (FS), carbachol and nitroprusside were applied consecutively to determine relaxation effects. This procedure was repeated after strips were deprived of glucose and oxygen (in vitro ischemia) for 1 h. The following parameters were quantitated for all responses: maximal tension change; maximal and mean rates of tension change, and time to maximal response.
Effects of 1-hour in vitro ischemia on rabbit corporal tissue were as follows: (1) an 85% decrease in contractile response to phenylephrine, and (2) a marked increase in rate of contractile response to phenylephrine. Phenylephrine precontracted strips exhibited: (3) no change in relaxant response to FS; (4) increased relaxant responses to carbachol and nitroprusside; (5) no change in rates of relaxation in response to FS; (6) increased rates of relaxation in response to carbachol and nitroprusside, (7) no change in elapsed time to maximal relaxation in response to FS, and (8) decreased elapsed time to maximal relaxation in response to carbachol and nitroprusside.
Digital analysis of the data generated facilitates recording, reviewing and analyzing of in vitro isometric tension studies on rabbit corpus cavernosum. Digital analysis allows quantification of additional parameters that have important implications for determination of mechanisms by which specific pathological processes occur.
阴茎勃起的起始依赖于海绵体平滑肌张力的调节。近年来，利用离体海绵体组织进行的体外等长张力研究已被广泛用于探究调节海绵体平滑肌张力和收缩的机制。在本研究中，我们对离体兔海绵体对各种形式刺激的收缩和舒张反应所产生的收缩数据进行了数字分析。对收缩和舒张数据的数字分析能够对张力变化的最大速率和平均速率以及达到最大反应所需的时间进行定量。张力变化速率可能为介导海绵体张力和变化的细胞事件提供额外的重要信息。
使用性成熟的雄性新西兰白兔。将每个海绵体从切除的阴茎上锐性分离，然后制备两条纵向条带用于等长张力研究，并置于单独的浴槽中。使用8通道Grass多导生理记录仪持续监测张力。Grass PolyVIEW系统同时将模拟信号转换为数字信息，并使用486个人计算机存储数据。每个海绵体条带先用300μmol/L去氧肾上腺素进行预刺激以产生最大收缩，然后依次施加场刺激（FS）、卡巴胆碱和硝普钠以确定舒张效果。在条带缺糖缺氧（体外缺血）1小时后重复此过程。对所有反应的以下参数进行定量：最大张力变化；张力变化的最大速率和平均速率，以及达到最大反应的时间。
1小时体外缺血对兔海绵体组织的影响如下：（1）对去氧肾上腺素的收缩反应降低85%，（2）对去氧肾上腺素的收缩反应速率显著增加。用去氧肾上腺素预收缩的条带表现出：（3）对FS的舒张反应无变化；（4）对卡巴胆碱和硝普钠的舒张反应增加；（5）对FS的舒张速率无变化；（6）对卡巴胆碱和硝普钠的舒张速率增加，（7）对FS达到最大舒张的时间无变化，以及（8）对卡巴胆碱和硝普钠达到最大舒张的时间减少。
对所产生数据的数字分析有助于对兔海绵体的体外等长张力研究进行记录、回顾和分析。数字分析能够对其他参数进行定量，这些参数对于确定特定病理过程发生的机制具有重要意义。
