A Potential imaging agent for the GABA A receptor: 4- t-butyl-1-(4-[ 123I]iodophenyl)-2, 6,7-trioxabicyclo-[2.2.2]octane

Abstract

Based upon the known high toxicity and high antagonist activity of t-butylorthobenzoates towards the GABA receptor complex, 4- t-butyl-1-(4-iodophenyl)-2,6,7-trioxabicyclo-[2.2.2]octane 5 and its radioiodo analogues ([ 123I]- 5 and [ 131I]- 5 were prepared as potential markers for the gated chloride channel of GABA A receptors. Mice showed rapid clearance of [ 131I]- 5 from all organs including the brain. The radioactivity was found to proceed into the urine in spite of the high lipophilicity of 5, the high binding affinity of 5 for plasma protein and the apparent chemical stability of 5 in plasma.