Acute noise stress in rats increases the levels of diazepam binding inhibitor (DBI) in hippocampus and adrenal gland

We investigated the effect of acute noise-induced stress on the concentrations of diazepam binding inhibitor (DBI) and its processing products in brain regions and adrenal glands of rats. DBI levels in hippocampus began to increase at 15 and 30 min and became significantly higher (+100%) at 90 and 120 min after stress; they returned to normal values at 360 min. While basal DBI levels were similar in the left and right hippocampus, the stress-induced increase of DBI levels was significantly higher in the left compared to the right side. A significant increase was also detected in the adrenals; here, the time course of DBI increase paralleled that of previously reported plasma corticosterone in stressed rats, being significantly higher 30 min after stress, and recovering to normal values at 60 and 90 min. After acute noise-induced stress, no significant change of DBI levels was detectable in cerebral cortex, striatum, hypothalamus and cerebellum. The present study reports for the first time the occurrence of a modification of DBI and its processing products (ODN-like immunoreactivity) in an experimental model of stress, and suggests a role for these neuropeptides in emotional responses.