title: Noncontact erection is enhanced by Ginkgo biloba treatment in rats: role of neuronal NOS in the paraventricular nucleus and sacral spinal cord.
abstract: BACKGROUND
  Nitric oxide (NO) is an important messenger mediating erection in the central nervous system (CNS). Paraventricular nucleus (PVN) neurons can be activated by NO and project the signals to the sacral spinal cord, which is involved in regulation of erection. Ginkgo biloba extract (EGb 761) facilitates noncontact erection (NCE) in rats; however, it is not clear whether EGb 761 increased NCE is associated with NO.
  
  
  OBJECTIVE
  The present study was designed to investigate the effects of neuronal nitric oxide synthase (nNOS) on NCE in rats following EGb 761 treatment.
  
  
  METHODS
  Adult Long-Evans male rats were treated with 50 mg/kg of EGb 761 or distilled water for 14 days. The NCE test was performed after 14 days of EGb 761 treatment and the NCE frequency was recorded. Approximately 14 h following the NCE behavioral tests, animals were sacrificed, and nNOS activity in the PVN and S6-L1 spinal cord was measured by immunohistochemistry and western blotting, respectively.
  
  
  RESULTS
  Treatment with 50 mg/kg of EGb 761 for 14 days increased the NCE numbers compared to either the controls treated with distilled water on the same day or the same group on day 0. Also, EGb 761 treatment enhanced nNOS-immunoreactive cell numbers in the PVN. Furthermore, western blot analysis showed that EGb 761-treated animals displayed higher levels of nNOS expression in the S1 spinal cord than controls.
  
  
  CONCLUSIONS
  Our results suggest that enhanced NCE in male rats administrated with EGb 761 may be related to the central nNOS activity in the PVN and the spinal cord.
authors.affiliation: Department of Physical Therapy, HungKuang University, No. 34 Chung-Chie Road, Sha Lu, Taichung, 443, Taiwan, Republic of China. d93441003@ntu.edu.tw
authors.forename: Kuei-Ying
authors.initials: KY
authors.lastname: Yeh
authors.forename: Ching-Hsiang
authors.initials: CH
authors.lastname: Wu
authors.forename: Yuan-Feen
authors.initials: YF
authors.lastname: Tsai
mesh_terms: D000818:Animals; D005260:Female; D020441:Ginkgo biloba; D007150:Immunohistochemistry; D008297:Male; D052248:Nitric Oxide Synthase Type I / Q000032:analysis / Q000502:physiology*; D010286:Paraventricular Hypothalamic Nucleus / Q000201:enzymology*; D010410:Penile Erection / Q000187:drug effects*; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D020318:Rats, Long-Evans; D013116:Spinal Cord / Q000201:enzymology*; D000096983:Ginkgo Extract
chemical_list: D052248:Nitric Oxide Synthase Type I; D010936:Plant Extracts; C063170:Ginkgo biloba extract; D000096983:Ginkgo Extract