Acute white noise exposure affects the concentration of benzodiazepine receptors in the brain of the rat.

Rats were acutely (45 min) exposed to 100-dB white noise, and benzodiazepine receptors in the cerebral cortex, hippocampus, and cerebellum were studied immediately after exposure by the receptor-binding assay using 3H-flunitrazepam as the ligand. An increase in the concentration of receptors was observed in the cerebral cortex, whereas no significant change in receptor concentration was seen in the hippocampus and cerebellum. No significant effect of noise on receptor binding affinity was detected in the three brain regions studied. Experimental handling also did not significantly affect the benzodiazepine receptor properties. These data confirm previous reports that acute exposure to stressor can cause rapid changes in benzodiazepine receptors in the brain.