Peripheral-type benzodiazepine receptor binding 4{prime}-IODO-PK11195: A new radioiodinated ligand for detecting lesioned brain areas
- Kyoto Univ., Osaka (Japan); and others
An increase in the peripheral-type benzodiazepine binding sites (PBBS) has recently been reported in excitotoxic and ischaemic lesions in the brain. Thus, PBBS visualization has been of greater interest due to the possibility of imaging the lesioned area as positive image. In this study, our interest is focussed in the development of a radioiodinated compound for the SPECT study of PBBS function. Taking account of the environment of binding sites and the stability in vivo, we selected the 4{prime}position of C-1 phenyl moiety of the isoqunoline derivative PK11195 as the best exploitable site for the iodination. The no-carrier-added I-125 labeled 4{prime}-iodo-PK11195 (IPK) was synthesized by the bromine-iodine exchange reaction in 60% radiochemical yield and > 98% radiochemical purity. In vitro competitive binding studies with H-3-PI11195 using rat kidney membranes shows that IPK has high affinity for PBBS as much as PK11195. The in vivo biodistribution in mice showed high uptake of I-125-IPK in the kidney, lung, heart and adrenal, organs reported as containing high PBBS, which were reduced by the treatment with cold PK11195. Furthermore, autoradiographic studies in transient middle cerebral arteries occlusion in rats showed high accumulation of I-125-IPK in lesioned sites, in contrast to the decease of radioactivity of Tc-99m-HM-PAO. Gathered data indicated that the newly designed IPK holds to great potential for detecting the lesioned brain areas as positive image.
- OSTI ID:
- 441617
- Report Number(s):
- CONF-950603-; ISSN 0161-5505; TRN: 96:002093-0042
- Journal Information:
- Journal of Nuclear Medicine, Vol. 36, Issue Suppl.5; Conference: 42. annual meeting of the Society of Nuclear Medicine, Minneapolis, MN (United States), 12-15 Jun 1995; Other Information: PBD: May 1995
- Country of Publication:
- United States
- Language:
- English
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