Oxygen-Induced Modifications of Benzodiazepine Receptors and D2 Dopamine Receptors in the Rat Under Hyperoxia

Peripheral-type benzodiazepine Receptors (PBR) in the kidney and Central-type Benzodiazepine Receptors (CBR) in the cerebral cortex were not affected in rats exposed to chronic hyperoxia (85% O₂, ATA, 6 days). Nevertheless, cortical CBR showed a significant decrease (29%) after hyperbaric hyperoxia (100% O₂, 3.5 ATA, 2h) in rats at a preconvulsive stage, with no concomitant alteration of kidney PBR. A similar down-regulation of striatal D₂ dopamine receptors was noticed (27%) - after hyperbaric hyperoxia— without any modification of cortical PBR. On the contrary, an up regulation of liver PBR was obtained in the same conditions (20%). It is likely that receptors implicated in neurotransmission are particularly down regulated or altered under hyperbaric hyperoxia.