Protection of the arterial internal elastic lamina by inhibition of the @entity3449 -angiotensin system in the XXXX .

@entity1811 @entity4688 @entity2514 @entity946 @entity1808 @entity3449 @entity9886 @entity397 @entity3591 @entity460 @entity35
Spontaneous @entity397 of the internal elastic lamina (IEL) occurs in some arteries of the @entity35 during growth and aging. Inbred, normotensive, Brown Norway (BN) @entity35 are particularly susceptible to @entity397 of the IEL, especially in the abdominal aorta (AA). Preliminary experiments showed that different @entity1811 ( @entity1811 ) inhibitors protect against @entity397 of the IEL in the BN @entity35 to a greater extent than @entity2514 , suggesting a role of the @entity3449 -angiotensin system (RAS) in this phenomenon. To explore this possibility, we have treated male BN @entity35 from 4.5 to 14 weeks of age with either @entity4688 or @entity9886 (both at 1, 3, and 10 mg x kg(-1) x d(-1)) or with the @entity460 antagonists @entity946 (at 3, 10, 30, and 45 mg x kg(-1) x d(-1)) and @entity3591 (at 30 mg x kg(-1) x d(-1)). Systolic blood pressure (SBP) was measured weekly, and at the end of treatment we (1) recorded body and heart weights, (2) measured various parameters of the RAS in plasma, (3) quantified interruptions in the IEL on "en face" preparations of AA, and (4) quantified elastin, collagen, and cell proteins in the media of the thoracic aorta. Results showed that @entity4688 and @entity9886 similarly decrease SBP and @entity397 of the IEL in the AA, suggesting that @entity4688 inhibits the latter via a decrease in the production of @entity1808 ( @entity1808 ) and not via another effect on @entity1811 . The decrease in IEL @entity397 and in SBP, as well as the modifications in the parameters of the RAS, were all dose dependent. @entity946 had little effect on the RAS and, at the highest doses, decreased SBP to an extent similar to that for @entity4688 at 3 mg x kg(-1) x d(-1) but did not significantly inhibit IEL @entity397 . @entity3591 decreased SBP, increased plasma @entity3449 concentration, and was without effect on IEL @entity397 . All treatments at the highest doses had a hypotrophic effect on the aortic media but differed in their effects on the heart, with @entity4688 and @entity9886 decreasing and @entity946 and @entity3591 increasing heart weight, suggesting that the inhibition of IEL @entity397 may be related to a cardiac hypotrophic effect. All these results, taken together, suggest that @entity1808 plays a role in the @entity397 of the IEL that is, in part, independent of SBP.
