Acute immune and non-immune inflammatory response in spontaneously hypertensive rats and normotensive rats. Role of endogenous nitric oxide

The present study investigated the acute inflammatory response (increase in vascular permeability and leukocytes migration) in the pleura of spontaneously hypertensive rats (SHR) and normotensive rats (NTR), using two different stimulus: carrageenan and active anaphylaxis. In addition, the role of endogenous nitric oxide in these responses was investigated. Results. The inflammatory response induced by intrapleural carrageenan injection in SHR developed similarly to that in NTR. Treatment with L-NAME, reduced the intensity of this response in both groups of rats. The inflammatory response induced by active anaphylaxis in SHR and NTR was different. The increase in vascular permeability occurred later in the SHR compared to NTR. The number of leukocyte present in inflammatory exudates was increased at 4 h in both groups of rats. L-NAME treatment did not inhibit exudation at the intervals under analysis, however, reduced the number of mononuclear cells in the inflammatory exudate of SHR. Conclusion. The development of the inflammatory response in SHR differs from that in NTR, depending on the nature of the inflammatory stimulus. Endogenous NO plays a clear role in carrageenan-induced inflamma-tion, but not in immunologically mediated inflammation in the analyzed period.