Developmental change in the nerve growth factor action from induction of choline acetyltransferase to promotion of cell survival in cultured basal forebrain cholinergic neurons from postnatal rats

Very little is known about the contribution of a low affinity neurotrophin receptor, p75, to neurotransmitter release. Here we show that nerve growth factor (NGF) induced a rapid release of glutamate and an increase of Ca 2؉ in cerebellar neurons through a p75-dependent pathway. The NGF-induced release occurred even in the presence of the Trk inhibitor K252a. The release caused by NGF but not brain-derived neurotrophic factor was enhanced in neurons overexpressing p75. Further, after transfection of p75-small interfering RNA, which downregulated the endogenous p75 expression, the NGF-induced release was inhibited, suggesting that the NGFinduced glutamate release was through p75. We found that the NGF-increased Ca 2؉ was derived from the ryanodine-sensitive Ca 2؉ receptor and that the NGF-increased Ca 2؉ was essential for the NGF-induced glutamate release. Furthermore, scyphostatin, a sphingomyelinase inhibitor, blocked the NGF-dependent Ca 2؉ increase and glutamate release, suggesting that a ceramide produced by sphingomyelinase was required for the NGF-stimulated Ca 2؉ increase and glutamate release. This action of NGF only occurred in developing neurons whereas the brain-derived neurotrophic factor-mediated Ca 2؉ increase and glutamate release was observed at the mature neuronal stage. Thus, we demonstrate that NGF-mediated neurotransmitter release via the p75-dependent pathway has an important role in developing neurons.

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Nerve Growth Factor-induced Glutamate Release Is via p75 Receptor, Ceramide, and Ca2+ from Ryanodine Receptor in Developing Cerebellar Neurons

Numakawa

Nakayama

Suzuki

et al. 2003

“…Cell Culture-Primary dissociated cultures were prepared from postnatal 2-or 3-day-old rat (SLC, Sizuoka, Japan) cortex as reported previously (26,27). Briefly, cells were gently dissociated with a plastic pipette after digestion with papain (90 units/ml, Worthington) at 37°C.…”

Section: Methodsmentioning

confidence: 99%

Brain-derived Neurotrophic Factor-induced Potentiation of Ca2+ Oscillations in Developing Cortical Neurons

Numakawa¹,

Yamagishi²,

Adachi

et al. 2002

Self Cite

Brain-derived neurotrophic factor (BDNF) has been reported to exert an acute potentiation of synaptic activity. Here we examined the action of BDNF on synchronous spontaneous Ca 2؉ oscillations in cultured cerebral cortical neurons prepared from postnatal 2-3-dayold rats. The synchronous spontaneous Ca 2؉ oscillations beganatapproximatelyDIV5.Itwasrevealedthatvoltagedependent Ca 2؉ channels and ionotropic glutamate receptors were involved in the synchronous spontaneous oscillatory activity. BDNF potentiated the frequency of these oscillations. The BDNF-potentiated activity reached 207 ؎ 20.1% of basal oscillatory activity. NT-3 and NT-4/5 also induced the potentiation. However, nerve growth factor did not. We examined the correlation between BDNF-induced glutamate release and the BDNF-potentiated oscillatory activity. Both up-regulation of phospholipase C-␥ (PLC-␥) expression and the BDNF-induced glutamate release occurred at approximately DIV 5 when the BDNF-potentiated oscillations appeared. We confirmed that the BDNF-induced glutamate release occurred through a glutamate transporter that was dependent on the PLC-␥/IP 3 /Ca 2؉ pathway. Transporter inhibitors blocked the BDNF-potentiated oscillations, demonstrating that BDNF enhanced the glutamatergic transmissions in the developing cortical network by inducing glutamate release via a glutamate transporter.Neurotrophins play important roles in the survival and differentiation of the peripheral nervous system and CNS 1 neurons. Besides having long term effects, neurotrophins play a fundamental role in neuronal plasticity in the short term (1). In particular, BDNF is essential to neuronal transmissions and activity-dependent neuronal plasticity (2-11). Application of BDNF to cultured hippocampal neurons induced an excitatory synaptic transmission (12), cation influx (13), generation of action potential (14), and Ca 2ϩ mobilization (15). Ca 2ϩ appears to affect processes that are central to the development and plasticity of the CNS (16), and several patterns of Ca 2ϩ dynamics are known. Spontaneous oscillations in the intracellular Ca 2ϩ concentration occur in developing CNS neurons, and their mechanisms are highly distinct. For example, the activation of nicotinic acetylcholine receptors is involved in the oscillatory activity of the retina, whereas a depolarization through the GABA A receptors is required for hippocampal oscillatory activity. Retinal oscillations are spatially restricted to the domains of amacrine and ganglion cells (17,18). By contrast, hippocampal activity consists of transient bursts in the intracellular Ca 2ϩ recurring synchronously over the entire population of pyramidal and interneurons (19). In the cerebral cortex, several patterns of Ca 2ϩ activity have been observed during cortical development, and the metabotropic glutamate receptors (mGluR), GABA A receptors, gap junctions, and ionotropic glutamate receptors are all able to mediate them. The Ca 2ϩ oscillations mediated by mGluR are triggered by mGluR agonists in neonatal or embryonic ...

“…Cell Culture-Primary cultures of dissociated cerebellar granule neurons were prepared from the cerebella of postnatal day 9 rats (Wistar ST, both sexes) as described previously (12)(13)(14)(15)(16). Briefly, cells were gently dissociated with a plastic pipette after digestion with papain (90 units/ml, Worthington) at 37°C.…”

Section: Methodsmentioning

confidence: 99%

p38 Mitogen-activated Protein Kinase Regulates Low Potassium-induced c-Jun Phosphorylation and Apoptosis in Cultured Cerebellar Granule Neurons

Yamagishi

Yamada

Ishikawa

et al. 2001

Self Cite

Cultured rat cerebellar granule neurons are widely used as a model system for studying neuronal apoptosis. After maturation by culturing in medium containing 26 mM potassium (high K ؉ ), changing to medium containing 5 mM potassium (low K ؉ ; LK) rapidly induces neuronal apoptosis. Then over 50% of granule cells die within 24 h. However, the molecular mechanisms by which the LK-induced apoptosis occurs in cultured cerebellar granule cells remain unclear. In the present study, we found that p38 MAP kinase (p38) was an important factor for LK-induced apoptosis. Three hours after changing to LK medium, p38 was markedly activated. In addition, SB203580, a specific inhibitor of p38, strongly inhibited the phosphorylation and expression of c-Jun in LK-induced apoptosis of cultured cerebellar granule cells. In vitro kinase assay using glutathione S-transferase-c-Jun as a substrate showed that p38 directly phosphorylated c-Jun. Furthermore, in the presence of SB203580, about 80% of neurons survived. These results indicate that p38 regulates LK-induced apoptosis of cerebellar granule neurons.