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Coexpression of ß1- and ß2-Adrenergic Receptors on Bovine Brain Capillary Endothelial Cells in Culture


Address correspondence and reprint requests to Dr. O. Durieu-Trautmann at Laboratoire d'Immuno-Pharmacologie Moléculaire, CNRS, Université Paris VII, Institut Cochin de Génétique Moléculaire, 22, rue Méchain 75014 Paris, France.


Abstract: The pharmacological study of the blood-brain barrier has often been hampered by the unavailability of a large number of pure and fully differentiated brain capillary endothelial cells. Here we describe a homogeneous culture of brain capillary endothelial cells isolated from bovine brain (BBECs), which retain at least some phenotypic characteristics of the functional blood-brain barrier: intercellular tight junctions and monoamine oxidase activity. These cells were subcultured in vitro, in the absence of any neuronal or glial influences, for > 100 doublings without any sign of senescence. The present study is focused on the expression of ß-adrenergic receptors on BBECs. By Northern blot hybridization, subtype-specific ligand binding, and cyclic AMP accumulation experiments, we demonstrate that ß1- and ß2-adrenergic receptors are coexpressed (in the respective proportions of 42 and 58%) on BBEC membranes and are functionally coupled to adenylate cyclase. This is the first report documenting a significant number of ß1-adrenergic receptors on brain capillary endothelial cells. The results are discussed in light of the known noradrenergic innervation of brain capillaries.