EXPRESSION OF ENDOTHELIN RECEPTORS AND NITRIC-OXIDE SYNTHASE IN THE BRAIN OF STROKE-PRONE SPONTANEOUSLY HYPERTENSIVE RATS WITH CEREBRAL APOPLEXY

Endothelin (ET) receptors, ET-1-like immunoreactivity and nitric oxide synthase (NOS) were examined in the brain of stroke-prone spontaneous ly hypertensive rats (SHRSPs) with cerebral apoplexy. Our receptor aut oradiographic method with I-125-ET-1 and unlabeled selective ligands f or ET receptors revealed de novo expressions of ETA and ETB receptors in areas of neural lesions with cerebrovascular damage in SHRSPs. Immu nohistochemical staining for ET-1 showed clear ET-1-like immunoreactiv ity in areas with highly expressed ET receptors. Histochemical studies on astrocytes and microglia suggested that these glial cells, aggrega ting in lesions, may carry ET receptors, ET-1-like immunoreactivity. F urthermore, NOS detected histochemically using an NADPH-diaphorase sta ining method was rich on glial cells in damaged areas of the brain in SHRSPs with cerebral apoplexy. Our data suggest the pathophysiological significance of glial ETA and ETB receptors, ET-1 and NOS in neural l esions of SHRSPs.