TEMPORAL AND SPATIAL-DISTRIBUTION OF HEAT-SHOCK MESSENGER-RNA AND PROTEIN (HSP70) IN THE RABBIT CEREBELLUM IN RESPONSE TO HYPERTHERMIA

We have previously investigated the expression of hsp70 genes in the h yperthermic rabbit brain at the mRNA level by Northern blot and in sit u hybridization procedures. Our studies have now been extended to the protein level utilizing Western blot and immunocytochemistry. Using an antibody which is specific to inducible hsp70, a prominent induction of hsp70 protein in glial cells of hyperthermic animals was noted. In particular, Bergmann glial cells in the cerebellum are strongly immuno reactive while adjacent Purkinje neurons are immunonegative. Extension of our in situ hybridization studies to a time course analysis reveal ed that the initial glial induction events were followed by a delayed accumulation of inducible hsp70 mRNA in Purkinje neurons at 10 hr post -heat shock. In control animals, high levels of constitutively express ed hsc70 mRNA and protein were observed in Purkinje neurons. Similar h sc70 and hsp70 mRNA observations were also made in neurons of the deep cerebellar nuclei and in motor neurons of the spinal cord. Our result s suggest that these neuronal cell types accumulate hsp70 mRNA in resp onse to hyperthermic treatment; however, the response is delayed when compared to the rapid response seen in glial cells. The high constitut ive levels of hsc70 in certain neuronal cell types may play a role in the initial dampening of the hsp70 induction response in these cells. (C) 1993 Wiley-Liss, Inc.