AJP - Regulatory, Integrative and Comparative Physiology, Vol 268, Issue 6 1394-R1400, Copyright © 1995 by American Physiological Society
Effect of chronic ANG I-converting enzyme inhibition on aging processes. V. Intracellular calcium-vasoreactivity coupling
C. Capdeville-Atkinson, L. Oster, N. Thorin-Trescases, A. Robert, B. Corman and J. Atkinson
Laboratoire de Pharmacologie Cardiovasculaire, Faculte de Pharmacie, Universite Henri Poincare Nancy 1, France.
Age-related changes in intracellular calcium ([Ca2+]i)-vasoreactivity
coupling efficiency (i.e., perfusion pressure divided by [Ca2+]i) were
studied in vitro in tail arteries of male, normotensive, WAG/Rij rats aged
6, 12, 24, or 30 mo; one-half of these were chronically treated with the
angiotensin I-converting enzyme inhibitor (ACEI) perindopril (1
mg.kg-1.day-1 orally) from 6 mo onward. Arterial segments were perfused at
a constant flow rate (perfusion pressure taken as an index of arterial
tone) and loaded with the acetoxymethyl ester of fluorescent dye fura 2
(fura 2-AM). Increases in [Ca2+]i were measured simultaneously with
vasoconstriction after stimulation with a depolarizing hyperkalemic
solution or the agonists norepinephrine or serotonin. Age had no effect on
increases in [Ca2+]i vasoconstrictor responses, or electromechanical
coupling efficiency (hyperkalemic solution). Increases in [Ca2+]i after
agonists were similar in all groups, but vasoconstrictor responses and
pharmacomechanical coupling efficiency decreased with age. ACEI had no
effect on vasoconstriction or [Ca2+]i signals. In conclusion, coupling
efficiency after agonist stimulation decreased with age; ACEI had no effect
on coupling efficiency.
