Norepinephrine Is Lateralized Within the Olfactory Bulbs of Male Mice

: Concentrations and in vitro release of norepinephrine were determined from left and right olfactory bulbs of adult male CD‐1 mice. Norepinephrine concentrations from the left olfactory bulbs were significantly greater than those of the right (p < 0.01). No statistically significant differences were obtained for dopamine, nor were there differences in tissue weights between the left and right olfactory bulb tissue samples. To verify further this asymmetry, release rates of norepinephrine were measured from superfused left and right olfactory bulbs. Norepinephrine output from the left olfactory bulb was significantly greater than that from the right (p < 0.05). These results show that norepinephrine is lateralized within the olfactory bulbs of male mice. This asymmetry shows a clear catecholamine specificity with regard to concentrations and may be related to the lateralized olfactory processing that has been reported to occur in humans.