Stress proteins as molecular markers of neurotoxicity

In response to many environmental and pathophysiologic stressful stimuli, c ells undergo a stress response characterized by induction of a variety of p roteins, including the heat shock protein family. The inducible heat shock protein 70 (hsp70) is believed to participate in an array of cellular activ ities, including cytoprotection. Normal brain cells have little detectable hsp70 RNA or protein. However, following a stressful condition hsp70 mRNA a nd protein are induced in different cell types depending on the severity an d the nature of the stimulus: The induction of hsp70 protein correlates wit h the regional and cellular vulnerability to a particular injury as identif ied by standard histologic methods. The pattern of hsp70 expression differs in response to various neurotoxic stimuli, including hyperthermia, ischemi a, seizures, hemorrhage, and N-methyl-D-aspartate receptor antagonist admin istration. Hsp70 expression is a useful marker of cellular injury and may h elp to identify previously unrecognized areas of vulnerability in the nervo us system after a neurotoxic stimulus. Hsp70 may also play a neuroprotectiv e role in the brain.