Renal ischemia-induced Fos expression in catecholaminergic neurons of rats

The present study was undertaken to define whether the renal artery occlusion (RAO) would activate the catecholaminergic neurons in the brainstem nuclei by double immunohistochemical method for detecting Fos and tyrosine hydroxylase. The results are as follows: (1) while the basal expression of Fos was relatively low in the brainstem, RAO was capable of inducing a robust Fos-like immunoreactive neurons in the nucleus tractus solitarius (NTS), area postrema (AP), nucleus paragigantocellularis lateralis (PGL) and locus coeruleus (LC); (2) numerous catecholaminergic neurons in NTS, AP, PGL and LC could be activated by RAO as shown by Fos expression; and (3) these responses to RAO were significantly attenuated by pretreatment with an adenosine receptor antagonist 8-phenyltheophylline. The results suggest that RAO can activate a large number of neurons including some catecholaminergic neurons in the brainstem nuclei. Such effects of renal ischemia may be attributed to RAO-induced adenosine release from the kidney which subsequently activates renal afferents.