Article

Dopamine receptor gene expression in human amygdaloid nuclei: elevated D4 receptor mRNA in major depression.

Department of Pharmacology, East Tennessee State University, Johnson City, TN 37614, USA.
Brain Research (impact factor: 2.73). 06/2008; 1207:214-24. DOI:10.1016/j.brainres.2008.02.009 pp.214-24
Source: PubMed

ABSTRACT Previous findings from this laboratory demonstrating changes in dopamine (DA) transporter and D2 receptors in the amygdaloid complex of subjects with major depression indicate that disruption of dopamine neurotransmission to the amygdala may contribute to behavioral symptoms associated with depression. Quantitative real-time RT-PCR was used to investigate the regional distribution of gene expression of DA receptors in the human amygdala. In addition, relative levels of mRNA of DA receptors in the basal amygdaloid nucleus were measured postmortem in subjects with major depression and normal control subjects. All five subtypes of DA receptor mRNA were detected in all amygdaloid subnuclei, although D1, D2, and D4 receptor mRNAs were more abundant than D3 and D5 mRNAs by an order of magnitude. The highest level of D1 mRNA was found in the central nucleus, whereas D2 mRNA was the most abundant in the basal nucleus. Levels of D4 mRNA were highest in the basal and central nuclei. In the basal nucleus, amounts of D4, but not D1 or D2, mRNAs were significantly higher in subjects with major depression as compared to control subjects. These findings demonstrate that the D1, D2 and D4 receptors are the major subtypes of DA receptors in the human amygdala. Elevated DA receptor gene expression in depressive subjects further implicates altered dopaminergic transmission in the amygdala in depression.

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Keywords

basal amygdaloid nucleus
 
basal nucleus
 
central nucleus
 
control subjects
 
D1 mRNA
 
D2 mRNA
 
D4 mRNA
 
D4 receptor mRNAs
 
D4 receptors
 
D5 mRNAs
 
DA receptor mRNA
 
depressive subjects
 
dopaminergic transmission
 
five subtypes
 
human amygdala
 
major depression
 
major subtypes
 
normal control subjects
 
Quantitative real-time RT-PCR
 
relative levels