title: Exogenous adenosine triphosphate and adenosine stimulate proximal sphincter of oddi motility via neural mechanisms in the anesthetized Australian possum.
abstract: We aimed to determine if exogenous adenosine triphosphate or adenosine modulated sphincter of Oddi motility and involved neural mechanisms. Sphincter of Oddi motility was recorded in anesthetized possums by manometry. Adenosine triphosphate or adenosine (1 microM-10 mM) was applied topically to the sphincter before and after pretreatment with tetrodotoxin, hexamethonium, atropine, or Nomega-nitro-L-arginine methyl ester. Sphincter contraction amplitude and frequency were quantified. Adenosine triphosphate induced a concentration-dependent increase in proximal sphincter contraction amplitude and frequency (P < 0.05). This response was reduced by tetrodotoxin and atropine but enhanced by hexamethonium and Nomega-nitro-L-arginine methyl ester. Adenosine concentration dependently increased proximal sphincter contraction amplitude (P < 0.05) only. This response was reduced by tetrodotoxin, atropine, and Nomega-nitro-L-arginine methyl ester, whereas hexamethonium had no effect. We conclude that exogenous adenosine triphosphate and adenosine stimulate proximal sphincter of Oddi motility via neural mechanisms, involving cholinergic motor neurons. Adenosine triphosphate may further modulate sphincter motility via nicotinic and nitrergic pathways.
authors.affiliation: Pancreatobiliary Research Group, Department of General and Digestive Surgery, Flinders Medical Centre, Bedford Park, SA 5042, Australia.
authors.forename: C M
authors.initials: CM
authors.lastname: Woods
authors.forename: J
authors.initials: J
authors.lastname: Toouli
authors.forename: G T P
authors.initials: GT
authors.lastname: Saccone
mesh_terms: D000241:Adenosine / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000700:Analgesics / Q000494:pharmacology*; D000758:Anesthesia; D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016473:Gallbladder Emptying / Q000187:drug effects / Q000502:physiology; D008365:Manometry; D009046:Motor Neurons / Q000187:drug effects* / Q000502:physiology; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D009803:Sphincter of Oddi / Q000187:drug effects* / Q000294:innervation* / Q000502:physiology; D048330:Trichosurus
chemical_list: D000700:Analgesics; D004791:Enzyme Inhibitors; D000255:Adenosine Triphosphate; D000241:Adenosine; D019331:NG-Nitroarginine Methyl Ester