Changes of renal peripheral benzodiazepine receptor in the stress/anxiety response

Peripheral benzodiazepine receptor(PBR) has been indentified in various peripheral tissues including kidney. The physiological and pharmacological functions of PBR are still uncertain, although it has been suggested that these are associated with the regulation of stress/anxiety response. Diazepam progeny, which were exposed to diazepam perinatally, was reported to be an animal model of chronic anxiety. However, PBR in the diazepam progenies are not known yet. In the present study, therefore, we examined the changes of PBR in the stress/anxiety response. Dams of rats were given injection of diazepam or vehicle during puerperium. Diazepam progenies showed increased level of anxiety on the performance of elevated plus maze, and increased Bmax of PBR. Saturation experiments followed by scatchard analysis of the results showed that the increase in the density of PBR and the affinity of the PBR remained unchanged. Forced swim stress increased anxiety on the plus maze in both groups of rats. In contrast to control, diazepam progenies did not show further upregulation of renal PBR immediately after swimming stress, but still higher than control. From the above results, it may be concluded that upregulation of renal PBR is associated with chronic anxiety as well as stress-induced response.