In vivo [I-125]-iodobenzovesamicol binding reflects cortical cholinergic deficiency induced by specific immunolesion of rat basal forebrain cholinergic system

In this study, radiolabeled iodobenzovesamicol (IBVM), which is known to bi nd with high affinity to the vesicular acetylcholine transporter, was teste d for its usefulness in imaging cortical cholinergic deficits in vivo. To i nduce reductions in cortical cholinergic input, the cholinergic immunotoxin 192IgG-saporin was employed. This has been shown to selectively and effici ently destroy basal forebrain cholinergic neurons in rats. The efficiency o f the immunolesion was verified by histochemical acetylcholinesterase stain ing. [I-125]-IBVM binding before and after lesioning was measured using aut oradiography. Basal forebrain cholinergic cell loss resulted in a considera ble reduction in [I-125]-IBVM binding in the cholinoceptive target regions, but not in the striatum and cerebellum, brain regions that do not receive a cholinergic input by the basal forebrain cholinergic nuclei, suggesting t hat [I-123]-IBVM has potential in imaging cortical cholinergic deficits in vivo, at least in animals. NUCL MED slot 27;1:23-31, 2000. (C) 2000 Elsevie r Science Inc. All rights reserved.