title: Pinealectomy increases ouabain high-affinity binding sites and dissociation constant in rat cerebral cortex.
abstract: The effect of the pineal gland on the ouabain high-affinity binding sites (Kd = 3.1 +/- 0.4 nM, Bmax = 246.4 +/- 18.4 fmol/mg protein) in rat cerebral cortex was studied. Pinealectomy increased Bmax (940.7 +/- 42.8 fmol/mg protein) and Kd (7.6 +/- 1.5 nM) while melatonin injection (100 micrograms/kg b.wt.) counteracted these effects, restoring kinetic parameters (Kd = 1.9 +/- 0.05 nM; Bmax = 262.2 +/- 29.6 fmol/mg prot) to control values. Melatonin activity on ouabain binding in vitro did not depend upon a direct effect on the binding sites themselves. However, in competition experiments, melatonin increased binding affinity of ouabain as shown by the decreased IC50 values.
authors.affiliation: Grupo de Investigación Comunicación Intercelular e Inmunología, Departamento de Fisiología, Facultad de Medicina, Granada, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Acuña Castroviejo
authors.forename: C M
authors.initials: CM
authors.lastname: del Aguila
authors.forename: B
authors.initials: B
authors.lastname: Fernández
authors.forename: M D
authors.initials: MD
authors.lastname: Gomar
authors.forename: J L
authors.initials: JL
authors.lastname: Castillo
mesh_terms: D000818:Animals; D001665:Binding Sites; D001693:Biological Transport, Active; D002540:Cerebral Cortex / Q000502:physiology*; D008297:Male; D010042:Ouabain / Q000378:metabolism*; D010870:Pineal Gland / Q000502:physiology*; D051381:Rats; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
chemical_list: D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase