Low-frequency stimulation inducible long-term potentiation at the accessory olfactory bulb to medial amygdala synapse of the American Bullfrog
Date
2016-02-22
Authors
deRosenroll, Geoff
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Abstract
The mitral cells of the accessory olfactory bulb (AOB) of anuran frogs project their
axons directly to the medial amygdala (MeA) along the accessory olfactory tract. An en
bloc preparation of the telencephalon of the American bullfrog Lithobates catesbeiana
was utilized to study a form of low-frequency inducible long-term potentiation (LTP)
expressed at the synapse formed between the terminals of the accessory olfactory tract
and the neurons of the MeA. Delivery of repetitive 1Hz-stimulation or sets of 5Hz tetani
to the accessory olfactory tract both induced potentiation that was stable for over an hour,
as measured by extracellular field recordings. LTP induced by 5Hz tetanus was
associated with a decrease in paired-pulse ratio, which would be consistent with an
increased probability of release contributing to the increased synaptic strength. Blockade
of neither NMDA nor kainate glutamate receptors, with AP5 and UBP310 respectively,
prevented LTP induction by 5Hz tetanus; however expression of LTP was partially
masked in the presence of UBP310. These results suggest that kainate receptors are
involved in the expression of LTP at the AOB-MeA synapse, though the means by which
LTP is induced remains unclear.
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Keywords
neuroscience, synaptic plasticity, LTP, physiology, bullfrog, amygdala, accessory olfactory system