Characterization of beta-adrenergic receptors in fresh and primary cultured bovine corneal endothelium.
Homogenates of fresh bovine corneal endothelium and of cells from primary cultures exhibited high affinity binding of [3H]-dihydroalprenolol, a specific beta-adrenergic antagonist. The binding was rapid and reversible. Specific binding of the radioligand in each preparation was saturable with half-maximal binding occurring at 0.5 nM. Homogenates of fresh tissue consistently showed a higher maximal binding capacity than did those from cell cultures. Both homogenates bound adrenergic agents in a manner consistent with the labelling of beta-adrenergic receptors. The relative affinities of epinephrine and norepinephrine indicated that beta-adrenergic receptors in both preparations are of the beta 2 subtype. The beta-adrenergic agonist, isoproterenol, increased the cAMP content of intact, cultured endothelial cells 27-fold over control. This effect was completely blocked by the beta-adrenergic antagonist, propranolol. Bovine corneal endothelial cells in primary culture contain beta-adrenergic receptors which are essentially identical to those from in vivo sources and appear to be linked functionally to cAMP synthesis in these cells.
Walkenbach
R J
RJ
Chao
W T
WT
Bylund
D B
DB
Gibbs
S R
SR
D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D003315:Cornea / Q000187:drug effects / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D004082:Dihydroalprenolol / Q000378:metabolism; D004727:Endothelium / Q000378:metabolism; D004837:Epinephrine / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism; D011433:Propranolol / Q000494:pharmacology; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D013997:Time Factors
D011943:Receptors, Adrenergic, beta; D004082:Dihydroalprenolol; D011433:Propranolol; D000242:Cyclic AMP; D007545:Isoproterenol; D009638:Norepinephrine; D004837:Epinephrine