Contractile responses of cultured bovine retinal pericytes to angiotensin II.
OBJECTIVE
To document that angiotensin (ANG) II contracts cultured bovine retinal pericytes via saralasin-sensitive receptors if the cells are prerelaxed.


METHODS
Changes in the contractile tone were quantified as the changes in the summed length of wrinkles induced by pericytes cultured on the silicone surface.


RESULTS
Angiotensin II (10(-5) mol/L) did not increase the contractile tone of cultured pericytes that were not prerelaxed. However, when the pericytes had been prerelaxed 41% with 10(-6)-mol/L sodium nitroprusside, ANG II at the range of 10(-7) to 10(-5) mol/L caused prompt, dose-related, significant (P<.01) contraction. It induced a maximum contraction (29.9%+/-5.2% [mean+/-SE]) at 10(-6) mol/L. This effect lasted at least 10 minutes. Angiotensin II receptor antagonist saralasin (10(-6) mol/L) abolished the contractile effect of ANG II (10(-6) mol/L), although by itself it did not affect the contractile tone.


CONCLUSIONS
Angiotensin II contracts cultured pericytes through saralasin-sensitive ANG II receptors. If ANG II affects the contractile tone of pericytes in vivo, it may affect capillary caliber, resistance, and blood flow.
Matsugi
T
T
Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami School of Medicine, Fla., USA.
Chen
Q
Q
Anderson
D R
DR
D000803:Angiotensin I / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D002196:Capillaries / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D002216:Captopril / Q000494:pharmacology; D002417:Cattle; D002478:Cells, Cultured / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D009599:Nitroprusside / Q000494:pharmacology; D012171:Retinal Vessels / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D012504:Saralasin / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000494:pharmacology
D000806:Angiotensin-Converting Enzyme Inhibitors; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D000804:Angiotensin II; D009599:Nitroprusside; D000803:Angiotensin I; D002216:Captopril; D012504:Saralasin