Age-related changes in angiotensin II-stimulated vascular contraction and inositol phosphate accumulation in Fischer 344 rats.
This study examined the influence of age on angiotensin II (AII)-stimulated vascular contractile responses and inositol phosphate (IP) accumulation in Fischer 344 rats. In the aorta, AII-stimulated contraction and IP accumulation were markedly reduced in 6- and 24-month-old rats compared to 1-month-old rats. There was not a significant difference in the contractile response to AII between 6- and 24-month-old rats, although IP hydrolysis showed a further decrease between 6 and 24 months. In tail artery, there were no differences in contraction and phosphoinositol metabolism in response to AII in the different ages. Losartan blocked AII-stimulated vascular contraction and IP hydrolysis in both aorta and tail artery while PD123319 did not inhibit either response. These data indicate that during maturation, there is a decline in AII-stimulated aortic contraction and IP accumulation in aorta but not in tail artery and these changes are due to altered AT1 receptor function.
Cai
G
G
Department of Pharmacology, Medical College of Pennsylvania, Philadelphia 19129.
Gurdal
H
H
Seasholtz
T M
TM
Johnson
M D
MD
D000375:Aging / Q000378:metabolism / Q000502:physiology*; D000804:Angiotensin II / Q000494:pharmacology*; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D001158:Arteries / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D001713:Biphenyl Compounds / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000378:metabolism*; D019808:Losartan; D008297:Male; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D011945:Receptors, Angiotensin / Q000145:classification / Q000502:physiology; D013777:Tetrazoles / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects*
D057911:Angiotensin Receptor Antagonists; D001713:Biphenyl Compounds; D007093:Imidazoles; D007295:Inositol Phosphates; D011725:Pyridines; D011945:Receptors, Angiotensin; D013777:Tetrazoles; D000804:Angiotensin II; C073402:PD 123319; D019808:Losartan