ISSN:
1432-1106
Keywords:
Neostriatum
;
Dopamine
;
Brain slices
;
Inward rectification
;
Firing pattern
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Intracellular recordings in in vitro slice preparations of rat brain were used to compare the actions of dopamine and dopamine receptor agonists on the subthreshold membrane properties of neostriatal neurons. A reproducible response for dopaminergic agonists was evoked after firing produced by current ramp injections that induced a subthreshold voltage displacement. Dopamine (10–100 μM) decreased both firing rate and membrane slope input resistance in virtually all cells tested. Input resistance change appeared as an increase in inward rectification. Approximate reversal potential was around -87 mV. The D1 receptor agonists SKF 38393 and C1-APB (1–10 μM) mimicked both dopamine effects with a reversal potential around -89 mV. The effects were blocked by the presence of 5–10 μM caesium (Cs+) but not by 1 μM tetrodotoxin, suggesting that main D1 effects on input resistance are due to subthreshold Cs+ sensitive conductances. cAMP analogues mimicked the actions of D1 receptor agonists. The D2 agonist, quinpirole (1–10 μM), did not produce any input resistance change, nonetheless, it still produced a decrease in firing rate. This suggests that the main D2 effect on firing is due to actions on suprathreshold ion conductances. All effects were blocked by D1 and D2 antagonists, respectively. D1 or D2 effects were found in the majority of cells tested.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00228552
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