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[Effects of beta-endorphin on glutamate neurotoxicity]

J Gao1, L Zhu, X Zhao

  • 1Department of Pharmacology, School of Medicine, Nanjing University, Nanjing 210093.

Yao Xue Xue Bao = Acta Pharmaceutica Sinica
|April 10, 2002
PubMed

Insights

Beta-endorphin exacerbates monosodium glutamate neurotoxicity by disrupting calcium homeostasis in neurons. This effect is linked to opioid-induced beta-endorphin release, suggesting a complex interaction in brain injury.

Area of Science:

  • Neuroscience
  • Neuroendocrinology
  • Cellular Biology

Context:

  • Monosodium glutamate (MSG) is a known neurotoxin, particularly affecting hypothalamic neurons.
  • Beta-endorphin (beta-End), an endogenous opioid peptide, plays roles in pain and stress responses.
  • Intracellular calcium ([Ca2+]i) is critical for neuronal function and survival.

Purpose:

  • To investigate the effects of beta-endorphin on monosodium glutamate (MSG)-induced neurotoxicity.
  • To determine the role of intracellular calcium ([Ca2+]i) in this interaction.
  • To explore the influence of opioids on beta-endorphin levels in the context of MSG neurotoxicity.

Summary:

  • Beta-endorphin (1.0 mg/kg) significantly aggravated MSG (0.5 g/kg)-induced neuronal injury in the hypothalamus.
  • Both MSG and beta-endorphin increased intracellular free calcium concentration ([Ca2+]i), with MSG having a greater effect.
  • Verapamil partially reversed the calcium changes induced by MSG and beta-endorphin.
  • MSG administration increased brain beta-endorphin content, further elevated by morphine.
  • Opioid-induced beta-endorphin release may contribute to the enhancement of MSG neurotoxicity.

Impact:

  • Reveals a novel mechanism by which beta-endorphin can worsen excitotoxicity.
  • Highlights the critical role of calcium dysregulation in neurotoxic processes.
  • Suggests potential therapeutic targets for conditions involving excitotoxicity and opioid modulation.

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