Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Absence of dopamine D4 receptors results in enhanced reactivity to unconditioned, but not conditioned, fear

Absence of dopamine D4 receptors results in enhanced reactivity to unconditioned, but not... The prefrontal cortex receives a major dopaminergic input from the ventral tegmental area, which plays an important role in the integration of neuronal signals influencing behavioural responses to stressful environmental stimuli. The dopamine D4 receptor (D4R) is expressed at highest levels in the prefrontal cortex and is the predominant D2‐like receptor localized in this brain area. To investigate the functional significance of D4Rs in dopamine‐mediated responses we have analysed a strain of mice lacking this receptor subtype (Drd4–/–). Wild‐type and Drd4–/– mice were challenged in two different approach/avoidance conflict paradigms: the elevated plus maze and the light/dark preference exploration test. By these behavioural measures Drd4–/– mice showed heightened avoidance to the more fear‐provoking areas of each maze as demonstrated by reduced exploration of the open arms of the plus maze and longer latencies to explore the illuminated compartment of the light/dark shuttle box. These exaggerated avoidance behaviours were further enhanced by an additional handling stress but completely prevented by anxiolytic agents such as the benzodiazepine midazolam and ethanol. Although Drd4–/– mice displayed heightened anxiety, they exhibited normal ethanol preference and consumption in a two‐bottle choice test. Learned fear responses evaluated by contextual, cued and instrumental fear‐conditioning tests showed no difference between wild‐type and Drd4–/– mice. Taken together these results indicate that the absence of D4Rs increases avoidance behaviour to unconditioned stimuli and does not impair behavioural reactions to Pavlovian fear‐conditioning, suggesting that the D4R could play a key role in the dopaminergic modulation of cortical signals triggered by environmental stimuli. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png European Journal of Neuroscience Wiley

Absence of dopamine D4 receptors results in enhanced reactivity to unconditioned, but not conditioned, fear

Loading next page...
 
/lp/wiley/absence-of-dopamine-d4-receptors-results-in-enhanced-reactivity-to-nVFfRopkL3

References (59)

Publisher
Wiley
Copyright
Copyright © 2002 Wiley Subscription Services, Inc., A Wiley Company
ISSN
0953-816X
eISSN
1460-9568
DOI
10.1046/j.0953-816x.2001.01842.x
Publisher site
See Article on Publisher Site

Abstract

The prefrontal cortex receives a major dopaminergic input from the ventral tegmental area, which plays an important role in the integration of neuronal signals influencing behavioural responses to stressful environmental stimuli. The dopamine D4 receptor (D4R) is expressed at highest levels in the prefrontal cortex and is the predominant D2‐like receptor localized in this brain area. To investigate the functional significance of D4Rs in dopamine‐mediated responses we have analysed a strain of mice lacking this receptor subtype (Drd4–/–). Wild‐type and Drd4–/– mice were challenged in two different approach/avoidance conflict paradigms: the elevated plus maze and the light/dark preference exploration test. By these behavioural measures Drd4–/– mice showed heightened avoidance to the more fear‐provoking areas of each maze as demonstrated by reduced exploration of the open arms of the plus maze and longer latencies to explore the illuminated compartment of the light/dark shuttle box. These exaggerated avoidance behaviours were further enhanced by an additional handling stress but completely prevented by anxiolytic agents such as the benzodiazepine midazolam and ethanol. Although Drd4–/– mice displayed heightened anxiety, they exhibited normal ethanol preference and consumption in a two‐bottle choice test. Learned fear responses evaluated by contextual, cued and instrumental fear‐conditioning tests showed no difference between wild‐type and Drd4–/– mice. Taken together these results indicate that the absence of D4Rs increases avoidance behaviour to unconditioned stimuli and does not impair behavioural reactions to Pavlovian fear‐conditioning, suggesting that the D4R could play a key role in the dopaminergic modulation of cortical signals triggered by environmental stimuli.

Journal

European Journal of NeuroscienceWiley

Published: Jan 1, 2002

There are no references for this article.