Housing conditions alter GABAA receptor of alcohol-preferring and -nonpreferring rats

The effects of housing conditions on some functional properties of the GABAA benzodiazepine (BZD) receptor in the cerebral cortex were examined in the selectively bred alcohol-preferring (P) and -nonpreferring (NP) lines of rats. Compared to rats housed in pairs (P with P and NP with NP), P and NP rats housed individually had 44% (p < 0.005) and 32% (p < 0.01) lower values, respectively, for GABA-stimulated 36Cl- influx into cortical microsacs. The maximal effect (Vmax) of flunitrazepam (FNZ) to enhance GABA-stimulated 36Cl- uptake was 44% higher in individually housed P rats than pair-housed P rats (p < 0.05) and 51% higher than individually housed NP rats (p < 0.05). There was no difference between single and pair-housed NP rats for Vmax values of FNZ enhancement of GABA-stimulated 36Cl- influx. The results show housing conditions can alter some of the functional properties of the GABAA/BZD receptor in the P and NP lines of rats. The differential effect of housing conditions on FNZ enhancement of 36Cl- influx, observed between the lines, may be a result of higher levels of anxiety being produced by brief isolation in the P rat.