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E Corwin

Publications and source records attributed to E Corwin.

7 recordsLinked to original sources
PubMed1984

Temperature sensitivity of the renin-angiotensin system in Ambystoma tigrinum.

The presence of a renin-angiotensin system was demonstrated in the poikilotherm Ambystoma tigrinum, commonly called the tiger salamander. Standard radioimmunoassay techniques were employed to measure the intrarenal renin activity (IRA) and the plasma renin activity (PRA) of A. tigrinum kept at either 5 or 20 degrees C. Basal IRA and PRA values were not affected by the temperature at which the animals were maintained. Intraperitoneal injection of the beta-adrenergic agonist isoproterenol, however, increased PRA only in those animals maintained at 20 degrees C. This is consistent with the hypothesis of a temperature sensitivity of the renal adrenergic system in vivo. In addition, we were able to demonstrate the existence of a contractile response of Ambystoma vascular smooth muscle to angiotensin II that was blocked by the competitive inhibitor saralasin.

Angiotensin I↗
PubMedDate not supplied

Effect of magnesium sulfate on the vascular actions of norepinephrine and angiotensin II.

Magnesium sulfate is used for seizure prophylaxis in patients with preeclampsia. It also has significant effects on calcium metabolism and could, therefore, alter the pressor response to calcium-dependent vasoconstrictors. The present in vivo rat study examined the effect of magnesium sulfate to alter the pressor response to norepinephrine (NE) and angiotensin II (A II). Magnesium doses were chosen to approximate those used in treating preeclampsia. NE resulted in a significant rise in mean arterial pressure (delta MAP, 46 +/- 3.7 mmHg; p < 0.001). A II also resulted in a significant rise in MAP (delta MAP, 23 +/- 3.6 mmHg, p < 0.02). Magnesium sulfate alone had no significant effect on MAP but attenuated the pressor response to both NE (delta MAP, 16 +/- 1.5 mmHg) and A II (delta MAP, 12 +/- 2.5 mmHg). After discontinuation of the magnesium sulfate infusion, the control pressor responses to NE and A II were again seen (delta MAP, 39 +/- 3.5 mmHg and delta MAP, 28 +/- 4.2 mmHg, respectively). Although magnesium sulfate is not a primary antihypertensive agent, it may have effects on blood pressure by attenuating the actions of circulating vasoconstrictors.

Angiotensin II↗