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Viewing report
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Presynaptic control of sensory input on the mammalian
olfactory system. Edition No. 1
VDM Publishing House, June 2009, Pages: 132
Presynaptic inhibition modulates signal transmission
in the olfactory pathway by several mechanisms, a
major one being mediated by GABAB receptors, which
suppress presynaptic calcium influx and subsequent
transmitter release from the receptor neuron
terminal. Presynaptic inhibition could function to
limit the strength of olfactory input to the central
nervous system, as well as provide a substrate for
centrifugal control of odorant representations early
in the olfactory system. Odorant and electrical
stimulation combined with in vivo pharmacology were
used to characterize the functional determinants of
GABAB-mediated presynaptic. The results of this work
showed that tonic inhibition is a major determinant
of receptor input strength; and were dependent on
glutamatergic transmission from second-order neurons
in the glomerular layer. When the behavioral state of
the awake animal was altered, odorant-evoked
responses were affected. Taken together these results
suggest that tonic inhibition via top-down,
centrifugal control plays a major role in modulating
the magnitude of sensory input to the brain as a
function of behavioral state.
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