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Identification of α 2 ‐Adrenergic Receptors in Chicken Pineal Gland Using [ 3 H]Rauwolscine
Author(s) -
Bylund David B.,
Rudeen P. Kevin,
Petterborg Larry J.,
RayPrenger Carla
Publication year - 1988
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1988.tb04838.x
Subject(s) - rauwolscine , oxymetazoline , receptor , prazosin , endocrinology , medicine , pineal gland , adrenergic receptor , radioligand assay , biology , binding site , chemistry , antagonist , biochemistry , melatonin
The norepinephrine‐induced inhibition of avian pineal N ‐acetyltransferase activity appears to be mediated by α 2 ‐ ‐ adrenergic receptors. In this study, α 2 ‐adrenergic receptors in the chicken pineal gland were directly identified by radioligand binding. Membrane preparations of pineal glands from chickens from 1 to 6 weeks of age were examined using [ 3 H]rauwolscine, a selective α 2 ‐adrenergic receptor antagonist, to characterize the binding sites. The results indicate no ontological change in either the affinity ( K D ) or density of receptor binding sites ( B max ) during the time span examined. The binding was saturable and of high affinity with a mean K D of 0.27 ± 0.01 n M and a mean B max of 242 ± 12 fmol/mg protein. Further characterization of these binding sites indicated that the α 2 ‐adrenergic receptor is of the α 2A subtype, since prazosin and ARC‐239 bound with low affinities and oxymetazoline bound with high affinity.