Ragazzi E, Chinellato A, Italiano G, Pagano F, Calabrò A
Department of Pharmacology, University of Padua, Italy.
Urol Res. 1996;24(6):317-22. doi: 10.1007/BF00389786.
In the present study we investigated the in vitro relaxant response of erectile tissue obtained from rabbits of different ages (3, 7 and 24 months) in order to detect the progression with age of cavernosal activity in response to substances acting via endothelium-dependent or -independent mechanisms. Noradrenaline induced a concentration-dependent contraction (0.1 microM-3 mM), with an increase in the contractility in the 24-month-old group. Acetylcholine produced a concentration-dependent relaxant effect in the three age groups, with a reduction of the maximal relaxant effect in older animals. ATP (10 microM-1 mM) and adenosine (10 microM-1 mM) induced a concentration-dependent relaxant effect that was higher in the older group. The presence of the NO2-synthase inhibitor N omega-nitro-L-arginine methyl ester (L-NAME) (0.1 mM) or of the P2-purinoceptor antagonist suramin did not affect ATP relaxation. Relaxation induced by sodium nitrite and nifedipine was reduced in older animals. In conclusion, aging selectively alters the in vitro responsiveness of rabbit erectile tissue. Purinergic system remains more active despite a decrease in the maximal endothelial cholinergic activity and the direct smooth muscle relaxant component.
在本研究中，我们调查了从不同年龄（3、7和24个月）的兔子获取的勃起组织的体外舒张反应，以检测海绵体活性随年龄增长对通过内皮依赖性或非依赖性机制起作用的物质的反应进程。去甲肾上腺素诱导浓度依赖性收缩（0.1微摩尔/升 - 3毫摩尔/升），24个月龄组的收缩性增加。乙酰胆碱在三个年龄组中产生浓度依赖性舒张作用，老年动物的最大舒张作用降低。ATP（10微摩尔/升 - 1毫摩尔/升）和腺苷（10微摩尔/升 - 1毫摩尔/升）诱导浓度依赖性舒张作用，在老年组中更高。一氧化氮合酶抑制剂Nω-硝基-L-精氨酸甲酯（L-NAME）（0.1毫摩尔/升）或P2嘌呤受体拮抗剂苏拉明的存在不影响ATP诱导的舒张。亚硝酸钠和硝苯地平诱导的舒张在老年动物中降低。总之，衰老选择性地改变了兔勃起组织的体外反应性。尽管最大内皮胆碱能活性和直接平滑肌舒张成分降低，但嘌呤能系统仍然更活跃。
