In vivo potentiation of vasopressors by spontaneously hypertensive rat plasma: correlation with blood pressure and calcium uptake.
Previous studies have shown that plasma from Spontaneously Hypertensive Rats (SHR) can potentiate the action of various vasopressors. Recently, we described a novel circulating hypertensive factor in the plasma of SHR rats which increases calcium uptake in vascular smooth muscle. In order to determine whether this factor might be responsible for the previously described pressor potentiation, the effect of dialyzed SHR plasma on the in vivo sensitivity of normotensive rats to norepinephrine, angiotensin II and arginine vasopressin was examined. Results of this study showed that SHR plasma potentiated the effects of all three pressor agents with peak potentiation occurring approximately 45-60 min post-plasma injection. The time course of pressor potentiation was similar to those for the hypertensive and cellular calcium effects of the plasma. These results suggest that a single factor may be responsible for the hypertensive, calcemic and pressor-potentiating effects of SHR plasma.
Lewanczuk
R Z
RZ
Department of Physiology, University of Alberta, Edmonton, Canada.
Pang
P K
PK
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D001158:Arteries / Q000378:metabolism; D001794:Blood Pressure; D002118:Calcium / Q000378:metabolism*; D004357:Drug Synergism; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011921:Rats, Inbred WKY; D013997:Time Factors; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D001127:Arginine Vasopressin; D002118:Calcium; D009638:Norepinephrine