In the present study we investigated the possibility that perindopril
changes the post synaptic vasoconstrictor activity to a variety of vasoconstrictive
agents. Perindopril (10 mg / kg / day) administrated orally to spontaneously
hypertensive rat (SHR) for 7 days, significantly reduced the potency
and the maximal vasopressor response to phenylephrine (40%) and
the maximal response to serotonirt (50%) compared with the responses
from vehicle treated STIR. In contrast, perindopril hod no significant effect
on the pressor responses to KCL
Furthermore, an eguipotent antihypertensive dose of hydralazine (5
mg / lcg / day, per oral for 7 days) exerted no inhibitory effect on the pressor
responses elicited by phenylephrine or KCI, but significantly reduced
the maximal response to serotonin. The results suggest that 7-days perindopril
administration reduced alpha adrenoceptor and -serotonergic receptor-
mediated vasoconstriction. However. perindopril did not reduce the
vasoconstrictor responses induced by KC1, indicating that those pressor
response that are due to depolarization are, in part, independent of angiotensin-
converting enzyme inhibition This inhibition of vascular adrenoceptor
and -serotonergic receptor pressor activity may underlie, in part,
the long-term antihypertensive activity of penindopril in the spontaneously
hypertensive rat. |
