Regional changes in [ 3H]diazepam binding in the brains of mice after removal of the olfactory bulbs

[ 3H]Diazepam binding was assayed 3 weeks after surgery in 13 brain regions derived from sham-operated and bilaterally olfactory bulbectomized mice. In bulbectomized mice, [ 3H]diazepam binding was elevated 30% in the frontal cortex and 24% in the thalamus but decreased 26% in the striatum and 28% in the midbrain. These changes represented alterations in the number of binding sites. No binding changes were observed in the olfactory tubercle, amygdala, piriform cortex, olfactory peduncle, hypothalamus, hippocampus, colliculi, cerebellum, or pons-medulla of bulbectomized animals. These results are compared with the effects of other types of brain lesions on the brain benzodiazepine receptor, and are possibly related to the altered sensitivity of bulbectomized mice to benzodiazepines and convulsants.