Reversibility of nerve growth factor's enhancement of choline acetyltransferase activity in cultured embryonic rat septum.
Choline acetyltransferase (ChAT) activity and survival of acetylcholinesterase (AChE)-positive neurons were measured in low-density cultures of embryonic (Day 14-15) rat septum exposed to various sequences of nerve growth factor (NGF) exposure and deprivation for up to 7 weeks in vitro. Most septal cultures grown 4-5 weeks with no exogenous NGF (including exposure to monoclonal or polyclonal antibodies against NGF) retained both a basal ChAT activity and the ability to increase ChAT activity in response to subsequently added NGF. When cultures were exposed to NGF (7S, 0.75 nM) for 2-3 weeks and then deprived of NGF for 2 weeks, ChAT activity fell gradually, but the number of AChE-positive neurons remained unchanged, and in many cases ChAT activity could be restored by subsequent re-exposure to NGF. Thus NGF's enhancement of ChAT activity in embryonic septal neurons in vitro is largely reversible and is not mediated by differential survival of cholinergic neurons.
Nonner
D
D
Department of Physiology and Biophysics, University of Miami School of Medicine, Florida 33101.
Brass
B J
BJ
Barrett
E F
EF
Barrett
J N
JN
D000818:Animals; D002470:Cell Survival; D002478:Cells, Cultured; D002795:Choline O-Acetyltransferase / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism*; D007106:Immune Sera / Q000276:immunology; D009414:Nerve Growth Factors / Q000276:immunology / Q000494:pharmacology*; D009474:Neurons / Q000201:enzymology; D010275:Parasympathetic Nervous System / Q000166:cytology; D051381:Rats; D012688:Septum Pellucidum / Q000196:embryology*
D007106:Immune Sera; D009414:Nerve Growth Factors; D002795:Choline O-Acetyltransferase