A role for delta opioid receptors in the central nucleus of the amygdala in anxiety-like behaviors

Rationale Compounds acting on delta opioid receptors (DOR) modulate anxiety-like behaviors, yet the site of action underlying this effect is unknown. DOR mRNA and protein are expressed in the central nucleus of the amygdala, a region that plays an important role in processing fear, stress, and anxiety. We hypothesized that this brain region may contribute to the modulation of anxiety by DOR drugs. Objective The present study investigated the role of DOR in the central amygdala in anxiety-like behaviors. Methods The selective DOR agonist [D-Pen 2,5]-enkephalin (DPDPE) or antagonist naltrindole was bilaterally microinjected into the central nucleus of the amygdala of adult male Sprague Dawley rats and anxiety-like behaviors were assessed using the elevated plus maze. The effects of DOR agonists on heightened anxiety produced by stress were also investigated. Results Rats injected with DPDPE into the central nucleus of the amygdala demonstrated less anxiety-like behavior, as evidenced by significantly greater number of open-arm entries and time spent in the open arms than controls. Naltrindole administered alone did not affect the duration or number of entries onto the open arms; however, naltrindole pre-treatment blocked the anxiolytic effects produced by DPDPE. Systemic administration of the selective DOR agonist, SNC80, or microinjection of DPDPE into the central amygdala prior to a swim stress blocked the anxiogenic effect produced by the swim stress. Conclusions These findings provide direct evidence that activation of DOR in the central amygdala reduces anxiety-like behavior and suggest that DOR in this area are important for regulating anxious states..

Medienart:

E-Artikel

Erscheinungsjahr:

2010

Erschienen:

2010

Enthalten in:

Zur Gesamtaufnahme - volume:212

Enthalten in:

Psychopharmacology - 212(2010), 4 vom: 21. Aug., Seite 585-595

Sprache:

Englisch

Beteiligte Personen:

Randall-Thompson, Jovita F. [VerfasserIn]
Pescatore, Karen A. [VerfasserIn]
Unterwald, Ellen M. [VerfasserIn]

Links:

Volltext [lizenzpflichtig]

Themen:

Anxiety
Central nucleus of the amygdala
DPDPE
Delta opioid receptor
Elevated plus maze
Naltrindole
SNC80
Swim stress

Anmerkungen:

© Springer-Verlag 2010

doi:

10.1007/s00213-010-1980-y

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

SPR002015633