[(3)H]ketanserin binding increases in monkey cortex following basal forebrain lesions with ibotenic acid

The present study investigated the effects of damage to the basal forebrain cholinergic system upon [(3)H]ketanserin binding in the neocortex and hippocampus of monkeys. [(3)H]Ketanserin specifically binds to serotonin type-2 receptor sites. Lesions were placed in the medial septal area, nucleus basalis, or both regions. Ten months later, [(3)H]ketanserin binding was increased in the neocortex, but not in the hippocampus, while levels of choline acetyltransferase (acetyl-CoA: choline O-acetyltransferase, EC 2.3.1.6) activity decreased in the neocortex and hippocampus. Changes in the levels of choline acetyltransferase and [(3)H]ketanserin binding were correlated significantly in the neocortex (r = ?0.64, P < 0.025), but not in the hippocampus. The data suggest that degeneration of the basal forebrain cholinergic system may alter serotonergic function in the neocortex.