Localization of synaptic responses in the in vitro turtle olfactory bulb using the [14C]2-deoxyglucose method.

Studies were carried out on the in vitro turtle olfactory bulb preparation with a modification of the [14C]-2-deoxyglucose (2-DG) technique. Electrical stimulation of either the dorsal or ventral division of the olfactory nerve produced broad bands of activity, spreading across laminae, in the corresponding half of the olfactory bulb. Pretreatment of the isolated preparation in a low calcium bath eliminated focal 2-DG uptake induced by electrical stimulation of the nerve. In contrast, pretreatment with the GABAergic antagonist, bicuculline, produced a notable increase in 2-DG accumulation. These findings are discussed in the light of the topographical innervation of the olfactory bulb by the olfactory nerve as well as the known synaptic organization of the olfactory bulb and the putative neurotransmitters operative in local circuits.