Journal of Neuroscience, Vol 15, 5574-5581, Copyright © 1995 by Society for Neuroscience
The D2 antagonist spiperone mimics the effects of olfactory deprivation on mitral/tufted cell odor response patterns
DA Wilson and RM Sullivan
Department of Zoology, University of Oklahoma, Norman 73019, USA.
Wistar rats had a single nare occluded on postnatal day 30, depriving the
ipsilateral olfactory bulb of odor stimulation. The deprivation lasted for
either 1-2 months (short-term) or 12 months (long-term). As previously
reported, deprivation greatly reduced tyrosine hydroxylase immunoreactivity
(the rate limiting enzyme for dopamine synthesis) in the glomerular layer
of the ipsilateral olfactory bulb. The nare was then reopened and odor
response patterns of mitral/tufted cells were examined. The proportion of
mitral/tufted cell single-units responding to a single odor was enhanced by
deprivation. Furthermore, the proportion of mitral/tufted cells responding
to more than one odor was increased by deprivation, suggesting a decrease
in discrimination. Finally, in undeprived bulbs, the dopamine D2 receptor
antagonist spiperone mimicked the effects of deprivation on mitral/tufted
cell odor response patterns. The results are interpreted as an activity-
dependent dopamine modulation of lateral and feedback inhibition in the
olfactory bulb, and are compared with similar events in the dark- adapted
retina.