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The Journal of Neurophysiology Vol. 85 No. 2 February 2001, pp. 699-707
Copyright ©2001 by the American Physiological Society
Institute for Neurobiology, University of Amsterdam, 1098 SM Amsterdam, The Netherlands
Joëls, M.,
C. Stienstra, and
Y. Karten.
Effect of Adrenalectomy on Membrane Properties and Synaptic
Potentials in Rat Dentate Granule Cells. J. Neurophysiol. 85: 699-707, 2001. Adrenalectomy is known to
accelerate both neurogenesis and cell death of granule cells located in
the suprapyramidal blade of the rat dentate gyrus. Three days after
adrenalectomy, some granule cells have already died by apoptosis while
newly formed cells are not yet incorporated in the cell layer,
resulting in a temporary loss of granule cells. Concomitantly, the
field response to stimulation of perforant path afferents is reduced.
While the temporary cell loss is likely to attenuate synaptic field
responses, adrenalectomy-induced changes in properties of the surviving
cells may also contribute to the reduction in field response amplitude. To address this possibility, we here investigated the membrane properties and synaptic responses of dentate granule cells, 3 days
after adrenalectomy. We found that passive and most of the active
membrane properties of granule cells in adrenalectomized rats were not
significantly different from the cell properties in sham-operated
controls. However, intracellularly recorded synaptic responses from
surviving granule cells were markedly reduced after adrenalectomy. The
N-methyl-D-aspartate (NMDA)- and the non-NMDA receptor-mediated components were reduced to a similar extent, suggesting that the attenuation of synaptic transmission after adrenalectomy could be partly of presynaptic origin. The data indicate
that the earlier observed attenuation of synaptic field responses after
adrenalectomy may be partly due to a diminished glutamatergic input to
the dentate gyrus and not exclusively to a loss of granule cells
participating in the synaptic circuit.
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