Inositol phosphate responses in portal veins from portal hypertensive rats: receptor- and nonreceptor-mediated responses.
OBJECTIVE
Venous hyporesponsiveness in portal hypertension has been reported previously by us. The present study was undertaken to investigate possible changes of phosphoinositide signal transduction pathway in the portal veins from portal hypertensive rats


METHODS
Portal hypertension was induced by partial portal vein ligation. Fourteen days after surgery, portal veins were removed for measurement of [3H]inositol phosphate responses to both receptor- and nonreceptor-mediated stimuli.


RESULTS
Basal [3H]inositol phosphate formation was similar between the two groups. Both phenylephrine and angiotensin II stimulated [3H]inositol phosphate formation in portal veins, but the responses were attenuated in the portal hypertensive group. In contrast, the [3H]inositol phosphate formation by nonreceptor-mediated stimuli (GTP gamma S, NaF/AlCl3, and phospholipase C) was similar between the two groups.


CONCLUSIONS
Our results showed that the receptor-mediated [3H]inositol phosphate formation was attenuated, while the non-receptor-mediated formation was unaltered, in the portal vein from portal hypertensive rats.
Huang
Y T
YT
Institute of Traditional Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
Chang
S P
SP
Lin
H C
HC
Yang
M C
MC
Hong
C Y
CY
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D000242:Cyclic AMP / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D019204:GTP-Binding Proteins / Q000502:physiology; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006975:Hypertension, Portal / Q000378:metabolism*; D007295:Inositol Phosphates / Q000096:biosynthesis*; D008297:Male; D011169:Portal Vein / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D007295:Inositol Phosphates; D000804:Angiotensin II; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000242:Cyclic AMP; D019204:GTP-Binding Proteins