title: Functional characterization of nonadrenergic noncholinergic neurotransmitter release via endocannabinoids: an in vitro study in rabbit corpus cavernosum.
abstract: BACKGROUND
  Corporal smooth muscle relaxation is mediated mainly but not completely by nitric oxide. Endocannabinoids modulate the various neurotransmitter systems.
  
  
  OBJECTIVE
  In the present study, a possible role of endocannabinoids on non-nitrergic nonadrenergic noncholinergic (NANC)-mediated relaxations was investigated.
  
  
  METHODS
  In precontracted tissues, control electrical field stimulation (EFS)-induced NANC relaxation responses were obtained using varying frequencies of stimulation in the presence of L-arginine methyl ester (L-NAME), guanethidine, and atropine. To investigate the effects of cannabinoids on EFS-evoked non-nitrergic NANC relaxation responses, a similar experimental procedure was applied in the presence of cannabinoid receptor antagonists AM251 or AM630; vanilloid receptor antagonist capsazepine; or cannabinoid receptor agonists anandamide, arachidonyl-2-chloroethylamide (ACEA), or JHW015.
  
  
  METHODS
  Effects of cannabinoid receptor antagonists and agonists on EFS-evoked non-nitrergic NANC relaxation responses.
  
  
  RESULTS
  L-NAME abolished EFS-induced relaxation responses at lower frequencies (2-4 Hz) and inhibited the relaxation responses at higher frequencies (8-32 Hz). AM251 and AM630 either together or separately inhibited, whereas anandamide, ACEA, and JHW015 enhanced non-nitrergic NANC relaxation responses. Anandamide did not alter EFS-induced non-nitrergic NANC relaxations in the presence of AM251 and AM630. Capsazepine enhanced non-nitrergic NANC relaxation responses.
  
  
  CONCLUSIONS
  These results suggest that non-nitrergic NANC relaxations may be mediated partially by cannabinoid-like neuronal factors acting at both cannabinoid CB(1) and cannabinoid CB(2) receptors.
authors.affiliation: Department of Pharmacology, Faculty of Medicine, Gazi University, Besevler, Ankara, Turkey.
authors.forename: Ismail M
authors.initials: IM
authors.lastname: Vural
authors.forename: Gokce S
authors.initials: GS
authors.lastname: Ozturk
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Sarioglu
mesh_terms: D000818:Animals; D001095:Arachidonic Acids / Q000008:administration & dosage / Q000494:pharmacology*; D001285:Atropine / Q000008:administration & dosage / Q000494:pharmacology; D015153:Blotting, Western; D063385:Cannabinoid Receptor Modulators / Q000378:metabolism*; D002186:Cannabinoids / Q000008:administration & dosage / Q000494:pharmacology*; D004558:Electric Stimulation / Q000379:methods; D063388:Endocannabinoids; D006145:Guanethidine / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects*; D019331:NG-Nitroarginine Methyl Ester / Q000008:administration & dosage / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism; D010276:Parasympatholytics / Q000008:administration & dosage / Q000494:pharmacology; D010413:Penis / Q000187:drug effects*; D053284:Polyunsaturated Alkamides / Q000008:administration & dosage / Q000494:pharmacology*; D011817:Rabbits; D011950:Receptors, Cholinergic / Q000187:drug effects*; D013565:Sympatholytics / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D001095:Arachidonic Acids; D063385:Cannabinoid Receptor Modulators; D002186:Cannabinoids; D063388:Endocannabinoids; D010276:Parasympatholytics; D053284:Polyunsaturated Alkamides; D011950:Receptors, Cholinergic; D013565:Sympatholytics; D009569:Nitric Oxide; D001285:Atropine; C078814:anandamide; D019331:NG-Nitroarginine Methyl Ester; D006145:Guanethidine