Lapchak_1994_Neurosci_60_293

Recent studies with nerve growth factor (NGF) have identified the pharmacological actions of this neurotrophin in a variety of animal models that mimic some of the neurotransmitter deficits that occur in Alzheimer's disease (AD, for reviews see Refs 7, 15, 17, 19). Based upon extensive pharmacological studies, NGF has been characterized as a crucial maintenance factor for adult cholinergic neurons of the septo-hippocampal and basalo-cortical pathways. Among the reported actions of NGF is an attenuation of lesion-induced decrements in presynaptic and postsynaptic cholinergic markers and functions in the hippocampal formation. Thus, in studies that used partial fimbriectomies to parallel the cholinergic neurodegeneration that occurs in AD, intraventricularly administered nerve growth factor prevented the loss of choline acetyltransferase (ChAT) and acetylcholinesterase immunoreactivity in the septum and increased a variety of presynaptic cholinergic markers involved in the synthesis, storage and release of the neurotransmitter acetylcholine (for reviews see Refs 7, 17, 19). More specifically, chronic NGF treatment attenuates lesion-induced reductions in hippocampal ChAT activity and high-affinity choline uptake, the end-result of which is an enhanced capacity to synthesize acetylcholine. This increased acetylcholine synthesis, in turn, appears to translate directly into augmented vesicular storage and release of the neurotransmitter. For instance, not only does NGF treatment reverse lesion-induced reductions in maximal binding densities of the acetylcholine vesicular transport marker [3H]vesamicol, but it also enhances acetylcholine release and turnover rate. NGF treatment also appears to restore the sensitivity of postsynaptic muscarinic receptors to agonist-induced stimulation following partial fimbriectomies.(ABSTRACT TRUNCATED AT 250 WORDS)