Distribution and characteristics of nerve growth factor binding on cholinergic neurons of rat and monkey forebrain

In sections of rat forebrain, perikarya labeled radioautographically with 125I-NGF resembled cholinesterase-positive neurons in their distribution within striatum and basal forebrain. Neurons with NGF receptors were also visualized in radioautographs prepared from the basal forebrain of a cerebrus monkey. Present techniques fail to detect axons projecting from basal forebrain to hippocampus or cortex which have been shown to take up NGF selectively in retrograde transport studies. In studies with membrane-enriched preparations from rat, high-affinity binding of 125I-NGF (half maximal saturation in the 15-30 pM range) was detected in basal forebrain and striatum; lower levels of high-affinity binding were seen in hippocampus and neocortex. The binding and molecular properties of these receptors are similar to those described in other NGF-responsive tissues. These observations are further evidence supporting a biological role for NGF on some forebrain cholinergic neurons in adult rat.