[Inhibition of the cysteamine-induced gastric ulcer by the sympathoadrenal medullary system in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY)].

We previously reported that cysteamine induces severe gastric ulcers in WKY, but very mild in SHR. The aim of this study is to elucidate the role on the sympathoadrenal medullary system in the pathogenesis of the cysteamine-induced gastric ulcer. Catecholamine (CA) contents in the stomach and adrenal gland were significantly higher in the non-treated SHR than in the non-treated WKY, suggesting that the sympathetic nervous system is more facilitated in SHR. Cysteamine decreased the noradrenaline and adrenaline contents in these tissues in both strains, however the values of CA was still higher in the treated SHR than the non-treated WKY. Histologically the adrenal medulla was severely damaged by cysteamine administration in WKY than in SHR. In contrast an immunohistological study revealed that chromogranin reactivity of the adrenal medulla was significantly stronger in the treated SHR than in the treated WKY. The celiac plexus was well preserved morphologically even in the cysteamine treatment in both strains. These results suggest that the capacity of the sympathetic nervous system in both the adrenal medulla and the stomach plays an important role in preventing the cysteamine-induced gastric ulcer in SHR.