Neuroprotection, excitotoxicicity and NMDA antagonists

ABSTRACT

PURPOSE: To analyze the main aspects of neuroprotection and excitotoxicity. DISCUSSION: This is a significant theory on the pathophysiology of cerebral ischemia; it is based on the release of excitatory aminoacid (EAA), mainly glutamate. The sequence starts with a decrease of the blood flow and ends in neuronal death. The main stages of this reaction are herein presented and discussed. An in depth study of the effects of the excessive intracellular calcium is undertaken. Neuroprotectors (NP) are a group of drugs that reduce the excitotoxicity, opposing the excessive release of EAA and its intracellular effects. Neuroprotectors represent a rational approach to stroke treatment and offer a number of potential advantages. They prevent or limit ischemia-induced damage. CONCLUSION: There are many experimental and clinical NP trials. A minimum of 800 trials are currently under study worldwide. The most important NP subgroups are N-methyl D-aspartate (NMDA) antagonists, gamma-amino butyric acid (GABA) agonists, amino-hydroxy-methyl-isoxalone propionic acid (AMPA) antagonists, reducers of intracellular Ca++ inhibitors of nitric oxide modulation pathway free radicals scavengers, sodium channel antagonists, glutamate release inhibitor, growth factors, hypothermia and potassium channel activators.