title: Increased density of I2-imidazoline receptors in human glioblastomas.
abstract: A glial location has been proposed for the non-adrenoceptor [3H]idazoxan binding site termed the I2-imidazoline receptor. The specific binding of [3H]idazoxan in the presence of (-)adrenaline was measured in membranes from excised human glioblastomas (n = 6), meningiomas (n = 6) and normal brains (n = 6). The pharmacological profile of the [3H]idazoxan binding in astrocytic tumours was similar to that in normal brain, compatible with the presence of I2-imidazoline receptors. There was a higher density of I2-imidazoline receptors in astrocytic tumours (Bmax = 266 +/- 18 fmol mg-1 protein; p < 0.001) than in normal brain (Bmax = 54 +/- 4 fmol mg-1 protein), with no differences in affinity values. Almost no [3H]idazoxan-specific binding was shown in meningiomas. The results suggest that I2-imidazoline receptors may be a selective marker for glial tumours in the evaluation of intracranial neoplasms.
authors.affiliation: Department of Pharmacology, University of the Basque Country, Leioa, Bizkaia.
authors.forename: J I
authors.initials: JI
authors.lastname: Martín-Gómez
authors.forename: J
authors.initials: J
authors.lastname: Ruiz
authors.forename: L F
authors.initials: LF
authors.lastname: Callado
authors.forename: J M
authors.initials: JM
authors.lastname: Garibi
authors.forename: L
authors.initials: L
authors.lastname: Aguinaco
authors.forename: F
authors.initials: F
authors.lastname: Barturen
authors.forename: J
authors.initials: J
authors.lastname: Javier Meana
mesh_terms: D000368:Aged; D001932:Brain Neoplasms / Q000378:metabolism* / Q000601:surgery; D016022:Case-Control Studies; D005260:Female; D005909:Glioblastoma / Q000378:metabolism* / Q000601:surgery; D006801:Humans; D019329:Idazoxan / Q000378:metabolism*; D054755:Imidazoline Receptors; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011869:Radioligand Assay; D011955:Receptors, Drug / Q000378:metabolism*
chemical_list: D054755:Imidazoline Receptors; D011955:Receptors, Drug; D019329:Idazoxan