Journal of Neuroscience, Vol 1, 1312-1319, Copyright © 1981 by Society for Neuroscience
The induction of "stress" proteins in organ slices from brain, heart, and lung as a function of postnatal development
FP White
The proteins synthesized in vitro by rat brain, heart, and lung slices were
compared by two-dimensional polyacrylamide gel electrophoresis. A protein,
P71, which is related to one of the heat shock proteins induced in many
cultured cells by hyperthermia and other harsh conditions, was the major
protein synthesized by all slices from rats 3 weeks old and older. In vivo
synthesis of P71 was not detected in brain, heart, or lung from these
animals nor was there any detectable Coomassie brilliant blue-stained
protein coinciding with P71 on the gels. P71 thus appears to be a minor
protein species in normal unstressed brain, heart, and lung. While both
heart and lung slices synthesized large quantities of P71 at all stages of
postnatal development, brain slices synthesized little, if any, P71 until 3
weeks postnatal. There was a dramatic decrease in protein synthesis in all
tissue slices during postnatal development. During this decrease, the
relative abundance of newly synthesized P71 remained almost constant in
heart and lung slices, but the relative abundance of P71 increased by
approximately 50-fold in brain slices. The cells synthesizing P71 in brain
slices were enriched in a microvascular fraction. The increase in P71
synthesis by these cells, occurring between the 3nd and 3rd postnatal week,
coincides with the final maturation of brain capillaries and the
blood-brain barrier.