title: Preparation and pharmacological characterization of [76Br]-meta-bromobenzylguanidine ([76Br]MBBG).
abstract: [76Br]-meta-Bromobenzylguanidine ([76Br]MBBG) was prepared from the iodinated analog (MIBG) and [76Br]NH4 using a Cu(+)-assisted halogen exchange reaction. [76Br]MBBG was produced in a 60-65% radiochemical yield with a specific activity of 20 MBq/nmol. In rats, biodistribution kinetic studies showed a high uptake of [76Br]MBBG in heart tissues with its maximum of 5% ID/S at 2 h p.i.; whereas 4 h p.i., the maximum of the heart-to-lung concentration ratio of 8 was observed. Metabolic studies in rats indicated that [76Br]MBBG was rapidly metabolized in plasma. However in heart tissue, 25 h p.i., 85% of the radioactivity still represented unchanged radiotracer. Pharmacological studies in rats showed that the myocardial uptake of [76Br]MBBG was similar to that of norepinephrine. After pretreatment of the rats, the uptake of [76Br]MBBG was reduced 4 h p.i. to the following values: after desipramine (DMI) to 37%, after dexamethasone (DXM) to 88% and after 6-hydroxydopamine (6-OHDA) to 16%. These preliminary results suggest that [76Br]MBBG can be useful for the assessment of heart catecholamine reuptake disorders with PET.
authors.affiliation: Service Hospitalier Frédéric Joliot, DRIPP, DSV-CEA, Orsay, France.
authors.forename: C
authors.initials: C
authors.lastname: Loc'h
authors.forename: K
authors.initials: K
authors.lastname: Mardon
authors.forename: H
authors.initials: H
authors.lastname: Valette
authors.forename: C
authors.initials: C
authors.lastname: Brutesco
authors.forename: P
authors.initials: P
authors.lastname: Merlet
authors.forename: A
authors.initials: A
authors.lastname: Syrota
authors.forename: B
authors.initials: B
authors.lastname: Maziere
mesh_terms: D000818:Animals; D001967:Bromine Radioisotopes / Q000737:chemistry* / Q000493:pharmacokinetics; D001969:Bromobenzenes / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D003891:Desipramine / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D006146:Guanidines / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D016627:Oxidopamine / Q000494:pharmacology; D051381:Rats; D014018:Tissue Distribution
chemical_list: D001967:Bromine Radioisotopes; D001969:Bromobenzenes; D006146:Guanidines; C083603:3-bromobenzylguanidine; D003907:Dexamethasone; D016627:Oxidopamine; D003891:Desipramine