Nitric oxide formation in the dog sphincter of Oddi from nitric oxide donors as measured with in vivo micro-dialysis.
BACKGROUND
Nitric oxide (NO) is known to play an important role in neurally mediated relaxation of the sphincter of Oddi.


OBJECTIVE
We investigated whether NO donors, such as nitroglycerin or zwitterionic polyamine/NO, applied into the common bile duct or intravenously, may induce the relaxation of the sphincter of Oddi by producing NO in the anaesthetized dog.


METHODS
NO production in the sphincter of Oddi was measured by detecting NO oxidation products (NO2- and NO3-) using micro-dialysis methods.


RESULTS
Zwitterionic polyamine/NO and nitroglycerin applied into the common bile duct induced a marked increase in NO2- but not NO3-, in the sphincter of Oddi. Intravenous infusion of zwitterionic polyamine/NO and nitroglycerin induced little or no increase in NO2- formation. Nitroglycerin infused into either the common bile duct or intravenously administered produced relaxation of the sphincter of Oddi, but zwitterionic polyamine/NO had no effect on the sphincter of Oddi in spite of the increase in NO2- levels.


CONCLUSIONS
Locally or systemically applied NO donors induce relaxation of the sphincter of Oddi by producing NO, although their mode of action differs in different analogues.
Yamamoto
I
I
Department of Second Surgery, Shiga University of Medical Science, Shiga, Japan.
Fujimura
M
M
Kihara
N
N
Kumano
K
K
Yamada
T
T
Yamamoto
H
H
Fujimiya
M
M
D000818:Animals; D003135:Common Bile Duct / Q000187:drug effects* / Q000502:physiology; D004285:Dogs; D005260:Female; D007262:Infusions, Intravenous; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D005996:Nitroglycerin / Q000494:pharmacology; D009803:Sphincter of Oddi / Q000187:drug effects* / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology
D020030:Nitric Oxide Donors; D014665:Vasodilator Agents; D009569:Nitric Oxide; D005996:Nitroglycerin