Nerve growth factor increases the synthesis and release of acetylcholine and the expression of vesicular acetylcholine transporter in primary cultured rat embryonic septal cells.
Acetylcholine (ACh) is synthesized by choline acetyltransferase (ChAT) in the cytoplasm of cholinergic nerve terminals and transported into synaptic vesicles by vesicular ACh transporter (VAChT). The genes encoding ChAT and VAChT are colocalized within the genome, and their products are known to be coregulated by various neurotrophic factors. In the present study, nerve growth factor (NGF; 100 ng/ml) was shown to enhance expression of VAChT and ChAT mRNA in primary cultured rat embryonic septal cells. By using a radioimmunoassay, we also found that NGF increased both neuronal content and spontaneous release of ACh, which were first detected on day 2 of culture and time-dependently increased up to day 10. Stimulated release of ACh elicited by high K+ (50 mM KCl) was also significantly greater in NGF-treated cells than in control cells. NGF enhanced immunoreactivity to antiserum against VAChT, indicating that the augmented responses were due to, at least in part, increased expression of VAChT protein. In contrast, the numbers of immunocytochemically positive cells were unaffected. Thus, NGF appears to augment ACh synthesis, its transport into synaptic vesicles, and its subsequent release. The data also suggest that NGF facilitates growth and development of cholinergic neurons, but not their survival.
Department of Pharmacology, Kyoritsu College of Pharmacy, Tokyo, Japan.
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H
Oosawa
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T
Fujii
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K
Kawashima
D000109:Acetylcholine / Q000096:biosynthesis* / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000096:biosynthesis*; D002478:Cells, Cultured; D004622:Embryo, Mammalian / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D026901:Membrane Transport Proteins; D009414:Nerve Growth Factors / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012688:Septum Pellucidum / Q000187:drug effects* / Q000196:embryology / Q000378:metabolism; D013268:Stimulation, Chemical; D013572:Synaptic Vesicles / Q000378:metabolism*; D050494:Vesicular Acetylcholine Transport Proteins; D033921:Vesicular Transport Proteins
D002352:Carrier Proteins; D026901:Membrane Transport Proteins; D009414:Nerve Growth Factors; D012333:RNA, Messenger; C493461:Slc18a3 protein, rat; D050494:Vesicular Acetylcholine Transport Proteins; D033921:Vesicular Transport Proteins; D000109:Acetylcholine; D011188:Potassium