Disappearance of β2-adrenergic receptors on astrocytes in canine distemper encephalitis:: possible implications for the pathogenesis of multiple sclerosis

It has been reported that astrocytes in the white matter of patients with multiple sclerosis (MS) lack beta (2)-adrenergic receptors. This abnormality might explain why astrocytes in active MS plaques aberrantly express major histocompatibility (MHC) class II molecules, which play an important role in the immunological cascade leading to myelin destruction. Canine distemper (CD) virus primarily infects astrocytes and causes a demyelinating disease in dogs that closely resembles MS. In control dogs, including three dogs with another inflammatory disease, beta (2)-adrenergic receptor immunoreactivity was observed on both neurons and astrocytes. In dogs with CD encephalitis, beta (2)-adrenergic receptors were present on neurons, but were absent on astrocytes in acute lesions, demyelinated lesions, and normal-appearing white matter. Similar to MS, several astrocytes in demyelinated lesions expressed MHC class II. These findings suggest that MS and the demyelinating stages of CD encephalitis have a common pathogenetic fatter, and that the loss of astrocytic beta (2)-adrenergic receptors in MS might be induced by a viral infection of astrocytes. NeuroReport 12:191-194 (C) 2001 Lippincott Williams & Wilkins.