Is there a relationship between blood pressure and intraocular pressure? An experimental study in hypertensive rats.
OBJECTIVE
Evaluation of relation between blood pressure (BP) and intraocular pressure (IOP) in two hypertensive rat strains: spontaneously hypertensive rats (SHR) and double transgenic (dTGR) (harboring human renin and angiotensinogen genes) rats, and in their normotensive control Wistar Kyoto and Sprague Dawley rats, respectively.


METHODS
Each rat strain was divided into medicated and non-medicated groups. Medicated rats were treated orally with an angiotensin II receptor type 1 blocker. IOP was measured using a specific rebound tonometer and BP by a tail-cuff method. Both parameters were determined in conscious animals every second week. For comparison, at the end of the study, IOP was measured in conscious and anesthetized rats.


RESULTS
The baseline IOP was higher in hypertensive rats vs their normotensive controls. Eight weeks of treatment with an angiotensin type 1 receptor blocker did not prevent a slight increase in IOP, although it abolished the development of hypertension in SHR. The markedly elevated IOP was reduced in medicated and non-medicated dTGR animals during the short follow-up period. General anesthesia reduced IOP significantly.


CONCLUSIONS
The results suggest a positive relation between BP and IOP in hypertensive rats.
Vaajanen
A
A
Institute of Biomedicine, Pharmacology, University of Helsinki, Finland.
Mervaala
E
E
Oksala
O
O
Vapaatalo
H
H
D000768:Anesthesia, General; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology; D000808:Angiotensinogen / Q000235:genetics; D000818:Animals; D030801:Animals, Genetically Modified / Q000235:genetics; D001794:Blood Pressure / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000503:physiopathology* / Q000517:prevention & control; D007429:Intraocular Pressure / Q000187:drug effects; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017207:Rats, Sprague-Dawley; D012083:Renin / Q000235:genetics
D047228:Angiotensin II Type 1 Receptor Blockers; D000808:Angiotensinogen; D012083:Renin