Structural changes during the early onset of experimental hypertension: trophic influences of the renin-angiotensin system.
All forms of established hypertension are characterised by hypertrophy of the heart and blood vessels. Although these structural alterations are a normal adaptation to raised blood pressure, it has been suggested that hypertrophy may develop by a mechanism independent of pressure. Some investigators claim that in the young spontaneously hypertensive rat, hypertrophy of the blood vessels and heart is present at a time before the rise in pressure. Evidence also exists to support the role of angiotensin II in directly influencing growth within the vasculature. The present study confirms that hypertrophy of the mesenteric resistance vessels is present in the 3-week old spontaneously hypertensive rat. However, enhanced vascular structure was also associated with a higher mean arterial blood pressure. No increase in activity of the renin-angiotensin system could be detected. These observations raise doubts as to whether hypertrophy of the blood vessels can develop independently of raised pressure.
MRC Blood Pressure Unit, Western Infirmary, Glasgow, UK.
J J
JJ
Morton
E C
EC
Beattie
S A
SA
Griffin
F
F
MacPherson
D000818:Animals; D001794:Blood Pressure; D001808:Blood Vessels / Q000378:metabolism / Q000473:pathology; D006973:Hypertension / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D051381:Rats; D011918:Rats, Inbred SHR; D011919:Rats, Inbred Strains; D011921:Rats, Inbred WKY; D012083:Renin / Q000378:metabolism; D012084:Renin-Angiotensin System
D012083:Renin