β-Adrenergic receptors were identified in slide-mounted sections of human trabecular meshwork by in vitro labeling, light microscopic autoradiography. Autoradiograms were generated after incubation of slide-mounted tissue sections with 125I-cyanopindolol, a selective high-affinity probe for β-adrenergic receptors. Experiments in which an excess of either unlabeled Practolol (β1 selective ligand) or Zinterol (β2 selective ligand) were included suggested that most of the receptors were of the β2 subtype. Data from displacement studies using increasing concentrations of the highly specific β1- and β2-adrenergic receptors antagonists, ICI-89,406 and ICI-118,551, respectively, confirmed the predominance of the β2-adrenergic receptors. Similar results obtained with cultured trabecular endothelial cells suggest that the β-adrenergic receptors may be associated with the endothelial cells of the trabecular meshwork in vivo. These results provide anatomic evidence for the hypothesis that β-adrenergic agents improve outflow by direct action on the trabecular meshwork and provide a rationale for the development of more selective β2-adrenergic agents to increase outflow facility.
|Original language||English (US)|
|Number of pages||8|
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - 1987|
ASJC Scopus subject areas
- Sensory Systems
- Cellular and Molecular Neuroscience