title: Nicotine in high concentration causes contraction of isolated strips of rabbit corpus cavernosum.
abstract: It is well known that cigarette smoke can cause erectile dysfunction by affecting the penile vascular system. However, the exact effects of nicotine on the corpus cavernosum remains poorly understood. Nicotine has been reported to cause relaxation of the corpus cavernosum; it has also been reported to cause both contraction and relaxation. Therefore, high concentrations of nicotine were studied in strips from the rabbit corpus cavernosum to better understand its effects. The proximal penile corpus cavernosal strips from male rabbits weighing approximately 4 kg were used in organ bath studies. Nicotine in high concentrations (10(-5)~10(-4) M) produced dose-dependent contractions of the corpus cavernosal strips. The incubation with 10(-5) M hexamethonium (nicotinic receptor antagonist) significantly inhibited the magnitude of the nicotine associated contractions. The nicotine-induced contractions were not only significantly inhibited by pretreatment with 10(-5) M indomethacin (nonspecific cyclooxygenase inhibitor) and with 10(-6) M NS-398 (selective cyclooxygenase inhibitor), but also with 10(-6) M Y-27632 (Rho kinase inhibitor). Ozagrel (thromboxane A2 synthase inhibitor) and SQ-29548 (highly selective TP receptor antagonist) pretreatments significantly reduced the nicotine-induced contractile amplitude of the strips. High concentrations of nicotine caused contraction of isolated rabbit corpus cavernosal strips. This contraction appeared to be mediated by activation of nicotinic receptors. Rho-kinase and cyclooxygenase pathways, especially cyclooxygenase-2 and thromboxane A2, might play a pivotal role in the mechanism associated with nicotine-induced contraction of the rabbit corpus cavernosum.
authors.affiliation: Advanced Urogenital Disease Research Center; Research Institute for Translational System Biomics; Department of Urology, Chung-Ang University Hospital, Seoul 156-755, Korea.
authors.forename: Hoai Bac
authors.initials: HB
authors.lastname: Nguyen
authors.affiliation: Department of Urology, Seoul Medical Center, Seoul 131-795, Korea.
authors.forename: Shin Young
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Department of Physiology, College of Medicine, Chung-Ang University, Seoul 156-756, Korea.
authors.forename: Soo Hyun
authors.initials: SH
authors.lastname: Park
authors.affiliation: Department of Urology, Hallym University Dongtan Sacred Heart Hospital, Hwaseong 445-170, Korea.
authors.forename: Jun Hyun
authors.initials: JH
authors.lastname: Han
authors.affiliation: Department of Physiology, College of Medicine, Chung-Ang University, Seoul 156-756, Korea.
authors.forename: Moo Yeol
authors.initials: MY
authors.lastname: Lee
authors.affiliation: Advanced Urogenital Disease Research Center; Research Institute for Translational System Biomics; Department of Urology, Chung-Ang University Hospital, Seoul 156-755, Korea.
authors.forename: Soon Chul
authors.initials: SC
authors.lastname: Myung
keywords: Contraction; Cyclooxygenase; Nicotine; Rabbit corpus cavernosum; Rho-kinase