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Changes in extracellular dopamine levels in the nucleus accumbens induced by low frequency stimulation of the ventral subiculum/CA1 region of the hippocampus Taepavarapruk, Pornnarin
Abstract
The present study utilized microdialysis in freely-moving rats to investigate 1) changes in extracellular dopamine (DA) level in the nucleus accumben (NAc) induced by electrical stimulation of the ventral subiculum/CAl (Vsub/CAl) area of hippocampus, and 2) the role of metabotropic glutamate receptors (mGluRs) in mediating DA release in the NAc induced by low frequency stimulation of Vsub/CAl. It has been shown that electrical stimulation of Vsub/CAl at 2 Hz for 100 secinduces a significant decrease (p < 0.05) in basal DA levels in the NAc which is long lasting throughout the 2 hr monitoring period. Reverse dialysis of the specific antagonist at mGluRl/2, (+)-α-methyl-4-carboxyphenylglycine (MCPG), at doses 10 μM and 100 μM, did not prevent the suppressive effects on DA levels induced by low frequency stimulation of Vsub/CAl. However, reverse dialysis with the group 2 and 3 mGluR antagonist, (+)-α-methyl-4-phosphonophenylglycine (MPPG), at dose of 100 μM and 1mM, significantly blocked the prolonged suppressive effects of 2 Hz Vsub/CAl stimulation on DA efflux. These results suggest that presynaptic group 2 and 3 mGluRs are likely to be involved in a mechanism underlying the late phase of synaptic transmission at glutamatergic-dopaminergic synapses in the NAc. However, the question which specific mGluR subtypes are responsible for these initial and long lasting suppressive mechanisms will require further research.
Item Metadata
Title |
Changes in extracellular dopamine levels in the nucleus accumbens induced by low frequency stimulation of the ventral subiculum/CA1 region of the hippocampus
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1998
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Description |
The present study utilized microdialysis in freely-moving rats to investigate
1) changes in extracellular dopamine (DA) level in the nucleus accumben (NAc)
induced by electrical stimulation of the ventral subiculum/CAl (Vsub/CAl) area of
hippocampus, and 2) the role of metabotropic glutamate receptors (mGluRs) in mediating DA release in the NAc induced by low frequency stimulation of Vsub/CAl.
It has been shown that electrical stimulation of Vsub/CAl at 2 Hz for 100 secinduces a significant decrease (p < 0.05) in basal DA levels in the NAc which is long lasting throughout the 2 hr monitoring period. Reverse dialysis of the specific antagonist at mGluRl/2, (+)-α-methyl-4-carboxyphenylglycine (MCPG), at doses 10 μM and 100 μM, did not prevent the suppressive effects on DA levels induced by low frequency stimulation of Vsub/CAl. However, reverse dialysis with the group
2 and 3 mGluR antagonist, (+)-α-methyl-4-phosphonophenylglycine (MPPG), at dose of 100 μM and 1mM, significantly blocked the prolonged suppressive effects of
2 Hz Vsub/CAl stimulation on DA efflux.
These results suggest that presynaptic group 2 and 3 mGluRs are likely to be
involved in a mechanism underlying the late phase of synaptic transmission at
glutamatergic-dopaminergic synapses in the NAc. However, the question which
specific mGluR subtypes are responsible for these initial and long lasting
suppressive mechanisms will require further research.
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Extent |
3071350 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-04-30
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0088421
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1998-05
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
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Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.