Effects of radiocontrast and endothelin administration on systolic blood pressure and renal damage in male spontaneously hypertensive and Wistar Kyoto rats with phentolamine-induced adrenergic blockade

RATIONALE AND OBJECTIVES. The systemic administration of hypertonic solutions may activate the adrenergic system, thus triggering vasomotor reactions that may result in renal failure, In this study the effects of diatrizoate meglumine sodium radiocontrast agent Hypaque-76 on systolic blood pressure (BP) and renal damage were determined in male spontaneously hypertensive (SH) rats and Wistar Kyoto (WKY) rats under adrenergic blockade. METHODS. The systolic BP was measured in ketamine-anesthetized male SH and WKY rats after administration of saline solution, radiocontrast, or endothelin during adrenergic blockade with phentolamine. Then the left kidney mas removed and examined histologically. RESULTS. The fall in systolic BP after phentolamine was not influenced by saline solution or radiocontrast in WKY rats but was restored partially by radiocontrast in SH rats. Endothelin produced an elevation in BP toward baseline levels in both strains. Only moderate renal damage was observed in the kidneys of WKY rats given radiocontrast or endothelin, but very severe damage was produced by these agents in SH rats. CONCLUSIONS. Adrenergic blockade with phentolamine did not prevent the elevation in systolic BP in SH rats by radiocontrast or by endothelin in SH and WKY rats, nor did it protect against renal damage by radiocontrast or by endothelin in SH rats.