Uckert Stefan, Fuhlenriede Mark H, Becker Armin J, Stief Christian G, Scheller Friedemann, Knapp Wolfram H, Forssmann Wolf G, Jonas Udo
Department of Urology, Hannover Medical School, 30625 Hannover, Germany.
Urol Res. 2003 Jun;31(2):55-60. doi: 10.1007/s00240-002-0292-z. Epub 2003 Mar 5.
For more then 15 years, there has been speculation on the significance of serotonergic pathways in the control of male sexual function, especially in the maintenance of penile flaccidity and the initiation of detumescence. However, only a few in vivo studies on peripheral serotonergic transmission have been carried out. The aim of the present study was to evaluate further the effects of serotonin (5-HT) on isolated human erectile tissue and to detect serum levels of 5-HT in the systemic and cavernous blood taken during different penile conditions from healthy males. The effects of 5-HT on isolated human corpus cavernosum (HCC) were investigated using the organ bath technique. A total of 41 healthy, adult male subjects were exposed to erotic stimuli in order to elicit penile tumescence and rigidity. Whole blood was simultaneously aspirated from the corpus cavernosum and the cubital vein during different penile conditions. Serum levels of 5-HT (ng/ml) were determined by means of an enzyme-linked immunosorbent assay. The cumulative addition of 5-HT (0.001-10 microM) induced contraction in the isolated HCC strips. The contractile response was abolished in the presence of 5-HT(1alpha)-receptor antagonist NAN-190. No attenuating effect of 5-HT was observed on electrically induced relaxation of the tissue. Moreover, amplitudes of relaxation remained unaltered in the presence of NAN-190. In the healthy volunteers, a significant increase in 5-HT levels was detected in the cavernous serum from flaccidity (113+/-62) to tumescence and rigidity (140+/-69 and 141+/-54, respectively), followed by a decrease in the detumescence phase (123+/-79). Changes in 5-HT levels in the systemic serum were less pronounced. Under all penile conditions, systemic 5-HT levels were higher than those registered in the cavernous serum. Although 5-HT does not appear to be involved in postsynaptic transmission in the HCC, our results may provide evidence for a physiological significance of 5-HT in the control of penile flaccidity and detumescence. Thus, our findings may give a rationale for the use of 5-HT antagonists in the pharmacotherapy of erectile dysfunction.
15年多来，人们一直在猜测血清素能通路在男性性功能控制中的意义，尤其是在维持阴茎疲软和启动消肿过程中的作用。然而，关于外周血清素能传递的体内研究却很少。本研究的目的是进一步评估血清素（5-羟色胺，5-HT）对离体人类勃起组织的影响，并检测健康男性在不同阴茎状态下采集的全身血液和海绵体血液中的5-HT血清水平。采用器官浴技术研究了5-HT对离体人类海绵体（HCC）的影响。共有41名健康成年男性受试者接受性刺激以诱发阴茎勃起和坚挺。在不同阴茎状态下，同时从海绵体和肘静脉抽取全血。采用酶联免疫吸附测定法测定5-HT的血清水平（纳克/毫升）。5-HT（0.001 - 10微摩尔）的累积添加可诱导离体HCC条带收缩。5-HT（1α）受体拮抗剂NAN - 190可消除收缩反应。未观察到5-HT对组织电诱导舒张有减弱作用。此外，在NAN - 190存在的情况下，舒张幅度保持不变。在健康志愿者中，从疲软状态（113±62）到勃起和坚挺状态（分别为140±69和141±54），海绵体血清中的5-HT水平显著升高，随后在消肿阶段下降（123±79）。全身血清中5-HT水平的变化不太明显。在所有阴茎状态下，全身5-HT水平均高于海绵体血清中的水平。虽然5-HT似乎不参与HCC中的突触后传递，但我们的结果可能为5-HT在控制阴茎疲软和消肿中的生理意义提供证据。因此，我们的发现可能为5-HT拮抗剂在勃起功能障碍药物治疗中的应用提供理论依据。
