Identification and characterization of the beta-adrenergic receptor on neuroblastoma x glioma hybrid NG108-15 cells.
1. Using [3H]DHA and unlabeled L-alprenolol, a substantial amount of over 64% specific binding of beta-adrenergic receptor has been identified on the neuroblastoma x glioma hybrid NG108-15 cell, which has been proven to display numerous functional characteristics of intact neurons. 2. Beta-adrenergic receptor binding on intact NG108-15 cells does not change significantly upon morphological differentiation, induced by 1 mM dibutyryl cyclic AMP (dBcAMP). 3. The [3H]DHA binding on intact NG108-15 cells is rapid, saturable, and reversible, having a t1/2 of 1.0 min for association and 3.5 min for dissociation. 4. The affinity constant (Kd) and maximum binding capacity (Bmax) for binding of [3H]DHA to beta-adrenergic receptors on NG108-15 cells have been estimated by Scatchard plot analysis to be 2.5 and 0.23 nM, respectively. Further analysis indicates a single class of receptors for [3HDHA binding on NG108-15 cells. 5. Studies on kinetic properties have revealed on-rate (K + 1) and off-rate (K - 1) constants of 0.7 X 10(-9) M min-1 and 0.19 min-1, respectively. Further, the IC50 value and inhibition constant (Ki) for unlabeled L-alprenolol to inhibit [3HDHA binding on NG108-15 cells have been estimated to be 10(-5) and 8.9 X 10(-6) M, respectively. 6. The rank-order potency of catecholamine agonists, (-)ISO greater than (+)ISO greater than EPI greater than NE, reveals the presence of type 2 receptor for the beta-adrenergic binding on both differentiated and undifferentiated NG108-15 cells. 7. The present study indicates that the clonal neuroblastoma x glioma hybrid NG108-15 cell line possesses substantial amounts of beta-adrenergic receptors with characteristics similar to those on neuronal cells.
Ghahary
A
A
Department of Physiology, University of Manitoba, WPG, Canada.
Cheng
K W
KW
D000526:Alprenolol / Q000378:metabolism; D003994:Bucladesine / Q000494:pharmacology; D002395:Catecholamines / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D004082:Dihydroalprenolol / Q000378:metabolism; D005910:Glioma / Q000473:pathology; D006822:Hybrid Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D007545:Isoproterenol / Q000494:pharmacology; D007700:Kinetics; D009447:Neuroblastoma / Q000473:pathology; D011943:Receptors, Adrenergic, beta / Q000032:analysis* / Q000378:metabolism; D013237:Stereoisomerism; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology
D002395:Catecholamines; D011943:Receptors, Adrenergic, beta; D004082:Dihydroalprenolol; D003994:Bucladesine; D000526:Alprenolol; D007545:Isoproterenol