title: Three phases of corporal tracing elicited by electrical field stimulation on rabbit corpus cavernosum smooth muscle in penile perfusion model.
abstract: BACKGROUND
  Nitric oxide (NO) has been shown to mediate electrical field stimulation (EFS)-caused smooth muscle relaxation. It is known that the neural control of penile erection involves adrenergic, cholinergic, and non-adrenergic-non-cholinergic (NANC) neuro-effector systems; however, the effects of EFS on adrenergic and cholinergic nerves are not clear.
  
  
  OBJECTIVE
  To elucidate EFS-induced signal transductions involved in adrenergic, cholinergic, and NANC neuro-effector systems by using an in vitro penile perfusion model.
  
  
  METHODS
  EFS was performed on penile corpus cavernosum smooth muscle from male New Zealand White rabbits, which was pre-contracted with L-phenylephrine (10 µM). We investigated the penile tracing elicited by EFS on tissues pre-incubated with guanethidine (Guan, 50 µM), tetrodotoxin (TTX, 10 µM), Nω nitro-L-arginine-methyl ester (L-NAME, 1 mM), atropine (50 µM), or eserine (10 µM).
  
  
  METHODS
  The time-to-peak of each phase, the percentage of relaxation, and the area under the curve (AUC).
  
  
  RESULTS
  We discovered an extraordinary phenomenon: three distinct phases elicited by EFS. Phase I was abolished by L-NAME. Phase II was decreased by eserine and Guan, but increased by L-NAME. Phase III was abolished by atropine, but enhanced by eserine and Guan. TTX diminished all three phases. The time to reach the top of phase I was delayed by TTX. The time to attain the peak of phase II was shortened by L-NAME, but delayed by TTX and atropine. The time to reach the top of phase III was shortened by L-NAME, eserine, and Guan. AUC was significantly decreased by L-NAME and TTX.
  
  
  CONCLUSIONS
  EFS stimulated adrenergic, cholinergic, and NANC neuro-effector systems simultaneously. Phase I was related to the NO pathway. Phase II was multiply affected by self-recovery properties, and adrenergic and cholinergic nerves. Phase III was related to cholinergic nerves. The corporal tracing elicited by EFS was the balanced result of multiple factors.
authors.affiliation: Department of Urology, Medical School, and Institute for Medical Sciences, Chonbuk National University, and Research Institute and CTC for Medical Device of Chonbuk National University Hospital, Jeonju, Korea.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhao
authors.forename: Kyung Woo
authors.initials: KW
authors.lastname: Cho
authors.forename: Jong Kwan
authors.initials: JK
authors.lastname: Park
mesh_terms: D000818:Animals; D019540:Area Under Curve; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D004195:Disease Models, Animal; D004558:Electric Stimulation; D007537:Isometric Contraction; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D010410:Penile Erection / Q000187:drug effects / Q000502:physiology*; D010413:Penis / Q000098:blood supply* / Q000187:drug effects / Q000502:physiology; D010830:Physostigmine / Q000494:pharmacology; D011817:Rabbits; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D002800:Cholinesterase Inhibitors; D010830:Physostigmine; D019331:NG-Nitroarginine Methyl Ester