Changes in distribution spaces and cell permeability caused by ATP in the rat liver.
OBJECTIVE
Cellular and extracellular volume changes caused by ATP were investigated in the liver as well as the possible formation of diffusion barriers, which could be responsible for some of its metabolic effects.


METHODS
The experimental system was the bivascularly perfused rat liver. [(14)C]Sucrose and [(3)H]water were simultaneously injected into either the portal vein or the hepatic artery. Mean transit times, distribution spaces, variances and linear superimpositions were calculated.


RESULTS
In the portal system, ATP reduced the transit time in the great vessels, had little or no effect on sinusoidal and cellular spaces, but impaired the flow-limited distribution of both [(14)C]sucrose and [(3)H]water. In the arterial bed ATP infused into either the portal vein or the hepatic artery produced vasodilation and increased the aqueous extra-sucrose space. These effects were inhibited by Nomega-nitro-L-arginine methyl ester infused into the hepatic artery.


CONCLUSIONS
Sucrose and extra-sucrose space changes caused in the arterial bed by portally infused ATP are most probably analogous to the transhepatic vasodilation effect already described for the rabbit liver. Impairment of flow-limited distribution of tracers in the sinusoidal bed indicates that ATP induces the formation of permeability barriers, which could be responsible for some of its metabolic effects.
Fernandes
T R L
TR
Laboratory of Liver Metabolism, University of Maringá, 87020900 Maringá, Brazil.
Suzuki-Kemmelmeier
F
F
de Oliveira
Denize Silva
DS
Bracht
A
A
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects* / Q000502:physiology; D004336:Drug Antagonism; D005110:Extracellular Space / Q000187:drug effects* / Q000378:metabolism; D006499:Hepatic Artery / Q000187:drug effects / Q000502:physiology; D008099:Liver / Q000098:blood supply / Q000187:drug effects* / Q000378:metabolism; D008102:Liver Circulation / Q000187:drug effects / Q000502:physiology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D010477:Perfusion; D011169:Portal Vein / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013395:Sucrose / Q000378:metabolism; D014018:Tissue Distribution; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects; D014867:Water / Q000378:metabolism
D014867:Water; D013395:Sucrose; D000255:Adenosine Triphosphate; D019331:NG-Nitroarginine Methyl Ester