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Autocrine—paracrine Regulation of Hippocampal Neuron Survival by IGF‐1 and the Neurotrophins BDNF, NT‐3 and NT‐4

Autocrine—paracrine Regulation of Hippocampal Neuron Survival by IGF‐1 and the Neurotrophins... In contrast to sympathetic and sensory neurons in the peripheral nervous system, the neurotrophic requirements for neurons in the central nervous system (CNS) have not been clearly identified. The inactivation of specific neurotrophic factors and their receptors by gene targeting has shown that there are no major changes in neuron numbers in the CNS. This suggests an overlap between the action of different neurotrophic factors in the brain during development. Here we have studied the survival of hippocampal neurons prepared from embryonic rats, using different culture conditions. Whereas the hippocampal neurons survive well in culture when plated at high density, they die at lower cell densities in the absence of appropriate neurotrophic factors. Under the latter conditions, both insulin‐like growth factor‐1 (IGF‐1) and the neurotrophins—brain‐derived neurotrophic factor (BDNF), neurotrophin‐3 (NT‐3) and neurotrophin‐4 (NT‐4)—rescued a large proportion of cultured neurons. In addition, hippocampal neurons from BDNF knockout mice exhibited enhanced cell death compared with cells from wild‐type animals. BDNF and IGF‐1 both increased the survival of the hippocampal neurons lacking BDNF, showing complementary action for these factors in supporting survival. Blocking antibodies against NT‐3 and IGF‐1 decreased hippocampal neuron survival at low cell densities, showing autocrine or paracrine action of the factors. At higher cell densities, however, the antibodies had no effect, demonstrating that there is a sufficient amount of endogenous factors supporting survival under these conditions. The present results show that hippocampal neurons depend for survival on local neurotrophic factors such as IGF‐1, BDNF and NT‐3, which act in an autocrine/paracrine manner. The multifactorial support of hippocampal neurons ensures a maximal degree of neuron survival even in the absence of an individual factor. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png European Journal of Neuroscience Wiley

Autocrine—paracrine Regulation of Hippocampal Neuron Survival by IGF‐1 and the Neurotrophins BDNF, NT‐3 and NT‐4

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References (65)

Publisher
Wiley
Copyright
Copyright © 1996 Wiley Subscription Services, Inc., A Wiley Company
ISSN
0953-816X
eISSN
1460-9568
DOI
10.1111/j.1460-9568.1996.tb01607.x
Publisher site
See Article on Publisher Site

Abstract

In contrast to sympathetic and sensory neurons in the peripheral nervous system, the neurotrophic requirements for neurons in the central nervous system (CNS) have not been clearly identified. The inactivation of specific neurotrophic factors and their receptors by gene targeting has shown that there are no major changes in neuron numbers in the CNS. This suggests an overlap between the action of different neurotrophic factors in the brain during development. Here we have studied the survival of hippocampal neurons prepared from embryonic rats, using different culture conditions. Whereas the hippocampal neurons survive well in culture when plated at high density, they die at lower cell densities in the absence of appropriate neurotrophic factors. Under the latter conditions, both insulin‐like growth factor‐1 (IGF‐1) and the neurotrophins—brain‐derived neurotrophic factor (BDNF), neurotrophin‐3 (NT‐3) and neurotrophin‐4 (NT‐4)—rescued a large proportion of cultured neurons. In addition, hippocampal neurons from BDNF knockout mice exhibited enhanced cell death compared with cells from wild‐type animals. BDNF and IGF‐1 both increased the survival of the hippocampal neurons lacking BDNF, showing complementary action for these factors in supporting survival. Blocking antibodies against NT‐3 and IGF‐1 decreased hippocampal neuron survival at low cell densities, showing autocrine or paracrine action of the factors. At higher cell densities, however, the antibodies had no effect, demonstrating that there is a sufficient amount of endogenous factors supporting survival under these conditions. The present results show that hippocampal neurons depend for survival on local neurotrophic factors such as IGF‐1, BDNF and NT‐3, which act in an autocrine/paracrine manner. The multifactorial support of hippocampal neurons ensures a maximal degree of neuron survival even in the absence of an individual factor.

Journal

European Journal of Neuroscience – Wiley

Published: Jul 1, 1996

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