TY - JOUR
T1 - High affinity binding of corticosterone to mammalian neuronal membranes
T2 - Possible role of corticosteroid binding globulin
AU - Orchinik, Miles
AU - Hastings, Nicholas
AU - Witt, Diane
AU - McEwen, Bruce S.
N1 - Funding Information:
Acknowledgements--We thank Dr C. Sue Carter for generously providing the breeding stock of prairie voles. We also thank Drs Robert Spencer, Firdaus Dhabhar, Frank Moore, Michael Moore, William Rosner and Christopher Lowry for valuable discussions concerning this manuscript. This work was supported by NIH grants MH41256 and NS07080 to B.S.M.M.O. was supported by a National Research Service Award postdoctoral fellowship (NS09129) from NINDS anti a fellowship from the Pharmaceutical Manufacturer's Association Foundation.
PY - 1997/2
Y1 - 1997/2
N2 - The signal transduction mechanisms mediating rapid steroid actions are poorly understood. To characterize corticosteroid interaction with neuronal membranes in a species with rapid behavioral responses to corticosterone, we examined [3H]corticosterone binding to membranes prepared from prairie vole brains. At 22°C, the rates of association and dissociation of [3H]corticosterone with well-washed synaptosomal membranes were very rapid. Specific binding was characterized by high affinity (K(d) = 6.01 nM) and low density (B(max) = 63.1 fmol/mg protein). The binding sites were highly specific for naturally occurring glucocorticoids and the density of binding sites appeared to vary by neuroanatomical region. Unlike most G-protein-coupled receptors, the high-affinity binding of [3H]corticosterone to vole brain membranes was unaffected by the addition of Mg2+ or guanyl nucleotides. Surprisingly, saline perfusion of vole brains before tissue homogenization greatly reduced high-affinity binding. In addition, the affinity and specificity of corticosteroid binding sites were similar in vole neuronal membranes and vole plasma. These data suggest that corticosteroid binding globulins may facilitate [3H]corticosterone binding to neuronal membranes. However, the addition of blood to perfused brains before homogenization did not restore high-affinity binding, so the role of plasma binding globulins is unclear. Whether these binding phenomena represent a technical artifact or a regulatory mechanism for corticosteroid action has yet to be determined.
AB - The signal transduction mechanisms mediating rapid steroid actions are poorly understood. To characterize corticosteroid interaction with neuronal membranes in a species with rapid behavioral responses to corticosterone, we examined [3H]corticosterone binding to membranes prepared from prairie vole brains. At 22°C, the rates of association and dissociation of [3H]corticosterone with well-washed synaptosomal membranes were very rapid. Specific binding was characterized by high affinity (K(d) = 6.01 nM) and low density (B(max) = 63.1 fmol/mg protein). The binding sites were highly specific for naturally occurring glucocorticoids and the density of binding sites appeared to vary by neuroanatomical region. Unlike most G-protein-coupled receptors, the high-affinity binding of [3H]corticosterone to vole brain membranes was unaffected by the addition of Mg2+ or guanyl nucleotides. Surprisingly, saline perfusion of vole brains before tissue homogenization greatly reduced high-affinity binding. In addition, the affinity and specificity of corticosteroid binding sites were similar in vole neuronal membranes and vole plasma. These data suggest that corticosteroid binding globulins may facilitate [3H]corticosterone binding to neuronal membranes. However, the addition of blood to perfused brains before homogenization did not restore high-affinity binding, so the role of plasma binding globulins is unclear. Whether these binding phenomena represent a technical artifact or a regulatory mechanism for corticosteroid action has yet to be determined.
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U2 - 10.1016/S0960-0760(96)00191-4
DO - 10.1016/S0960-0760(96)00191-4
M3 - Article
C2 - 9191981
AN - SCOPUS:0030904861
SN - 0960-0760
VL - 60
SP - 229
EP - 236
JO - Journal of Steroid Biochemistry and Molecular Biology
JF - Journal of Steroid Biochemistry and Molecular Biology
IS - 3-4
ER -