Maternal behavior: glutamic acid decarboxylase activity in the olfactory bulb of the rat.

Disruption of mother-pup interaction by pup deprivation induced an increase of glutamate decarboxylase (GAD) activity in the main and accessory olfactory bulbs (OB) of lactating rats. The presentation of pups to deprived mothers with restriction of suckling and tactile interaction decreased GAD activity in the main bulb to the levels of lactating rats. The accessory bulb enzymatic activity was similar to that of lactating rats when the pups were returned completely to deprived mothers. Deafferentation of OB did not modify the enzymatic activity in nonlactating rats. In lactating mothers deafferentation decreased GAD activity in the accessory OB compared to the main OB and also had less activity than the accessory OB mothers without deafferentation. Deafferentation in deprived mothers decreased GAD activity in both main and accessory OB. These results indicate a role for GABA neurotransmission in olfactory bulbs of lactating rats.