Prakash A, Zhang H, Pandey SC. Innate differences in the expression of brain-derived neurotrophic factor in the regions within the extended amygdala between alcohol preferring and nonpreferring rats.
Alcohol Clin Exp Res 2008;
32:909-20. [PMID:
18445109 DOI:
10.1111/j.1530-0277.2008.00650.x]
[Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND
Animal lines such as alcohol-preferring (P) and nonpreferring (NP) rats appear to be suitable animal models to investigate the biological basis of alcohol-drinking behaviors. The extended amygdala serves as a neuroanatomical substrate for alcohol-drinking behaviors. Brain-derived neurotrophic factor (BDNF) in the amygdala has been implicated in alcohol-drinking behaviors; however, its expression in the extended amygdala of P and NP rats is unknown. Therefore, we examined the basal expression of BDNF in the extended amygdala of alcohol naive P and NP rats.
METHODS
We determined the basal mRNA and protein levels of BDNF by in situ RT-PCR and immuno-histochemical procedure, respectively, in the amygdaloid [central nucleus of amygdala (CeA), medial nucleus of amygdala (MeA), and basolateral amygdala (BLA)], nucleus accumbal (NAc shell and core), and bed nucleus of stria terminalis (BNST) [lateral BNST (lBNST), medial BNST (mBNST), and ventral BNST (vBNST)] brain structures of P and NP rats. In addition, we examined the localization of BDNF in neurons using double-immunofluorescence labeling of BDNF with neuron-specific nuclear protein (NeuN) and also determined the number of NeuN-positive neurons in the amygdaloid structures of P and NP rats.
RESULTS
The mRNA and protein levels of BDNF were found to be significantly lower in both the CeA and MeA, but not in the BLA, of P compared with NP rats. We also found that BDNF was expressed in neurons in the amygdaloid structures of P and NP rats. In addition, we found that the number of NeuN-positive neurons was similar in the amygdaloid structures of P and NP rats. Interestingly, the mRNA and protein levels of BDNF were also significantly lower in the lBNST, mBNST, and vBNST of P compared with NP rats. On the other hand, mRNA and protein levels of BDNF were similar in the NAc shell and core structures of P and NP rats.
CONCLUSIONS
P and NP rats are selectively bred for higher and lower alcohol preference, respectively; therefore it is possible that lower BDNF levels in the amygdaloid and BNST structures may be associated with the excessive alcohol-drinking behaviors of P rats.
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