AUTHOR=Senbel Amira M. , Abd Elmoneim Heba M. , Sharabi Fouad M. , Mohy El-Din Mahmoud M. 

TITLE=Neuronal Voltage Gated Potassium Channels May Modulate Nitric Oxide Synthesis in Corpus Cavernosum

JOURNAL=Frontiers in Pharmacology

VOLUME=Volume 8 - 2017

YEAR=2017

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2017.00297

DOI=10.3389/fphar.2017.00297

ISSN=1663-9812

ABSTRACT=Potassium channels (K+Ch) in corpus cavernosum play an important role in the regulation of erection. Nitric oxide (NO) acts through opening of K+Ch leading to hyperpolarization and relaxation. Aim: This study aims to update knowledge about the role of voltage-gated K+Ch (Kv) channels in erectile machinery and investigate their role in the control of NO action &/or synthesis in the corpus cavernosum. Methods: Tension studies using isolated rabbit corpus cavernosum (CC) strips and rat anococcygeus muscle were conducted. Results are expressed as mean ± SEM. Results: Electric field stimulation (EFS, 2-16 Hz) evoked frequency-dependent relaxations of the PE (phenylephrine)- precontracted CC strips. At 2 Hz, EFS-induced relaxation amounted to 73.17±2.55% in presence 4-AP (10-3 M) compared to 41.98±1.45% as control. None of the other selective K+Ch blockers tested inhibited EFS-induced relaxation. 4-AP (10-3M) significantly attenuated ACh-induced relaxation of rabbit CC where dose-response curve was clearly shifted upward, and attenuated SNP-induced relaxation, for example, to 49.28±4.52% compared to 65.53±3.01% as control at 10-6 M SNP. The potentiatory effect of 4-AP on EFS was abolished or reversed in presence of NG-nitro-L-arginine (L-NNA, non-selective nitric oxide synthase inhibitor, 10-5M and 2x10-4M). Same results were observed in rat anococcygeus muscle which is a part of the erectile machinery in rats. Conclusion: This study provides evidence for the presence of prejunctional voltage-gated K+Ch in CC, the blockade of which may increase the neuronal synthesis of NO.