Role of endothelin B receptor signals in reactive astrocytes.

We investigated the involvement of endothelinB receptor signals in the activation of astrocytes in vitro and in vivo. Endothelin reversed the stellate morphology of astrocytes induced by several agents. Endothelin stimulates astrocytic stress fiber formation. This effect of endothelin is Ca2+-independent and mediated by rho protein signal cascades linked to tyrosine phosphorylation. Injection of endothelin into striatum caused reactive astrocytosis which is prevented by a systemic injection of endothelinB receptor antagonist. We propose the role of endothelinB receptor signal transduction in reactive astrocytes.