| Abstract No.: | C-G3198 |
| Country: | Canada |
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| Title: | THE RELEVANCE OF BDNF EFFECTS ON THE MESOLIMBIC DOPAMINE SYSTEM FOR VARIATIONS IN MATERNAL CARE |
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| Authors/Affiliations: | 1 Dara K. Shahrokh*; 1 Josie Diorio; 1 Michael Meaney;
1 McGill University, Douglas Hospital, Montreal, QC, Canada
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| Content: | Objectives: The aim of the current study was to investigate the role of BDNF in maternal behavior and to see if variations in maternal care can effect the interaction between dopamine and BDNF in the mesolimbic sytem.
Introduction: Naturally occurring variations in maternal licking/grooming (LG) of pups influence neural development, and are transmitted from mother to female offspring. Brain-derived neurotrophic factor (BDNF) is a polypeptidic factor initially regarded to be responsible for neuron proliferation, differentiation and survival through its uptake at nerve terminals and retrograde transport to the cell body. Interestingly, BDNF also elicits long-term neuronal adaptations by controlling the responsiveness of its target neurons to dopamine and is also responsible for inducing normal expression of the dopamine D3 receptor in nucleus accumbens (nAcc). Moreover high LG mothers show an increase in the duration and amplitude of extracellular dopamine in the nucleus accumbens shell (nAcc) during nursing bouts.
Materials and Methods: In situ hybridization was performed on high and low LG rats on post partum day 4 (PP4) in order to look at BDNF and TrkB mRNA levels. An autoradiography was performed on the tissue taken from the same animals to assess D3 receptor binding. Finally, ELISAs were used to quantify BDNF protein levels from tissue that was punched from freshly frozen brains.
Results: The results revealed an increase in BDNF expression at the level of mRNA in the hippocampus and ventral tegmental area (VTA) of high LG mothers on PP4: Both regions project to the nAcc. The analysis for TrkB mRNA levels in the nAcc shell and the VTA at PP4 revealed no significant differences between high and low LG dams. The results also revealed an increase in BDNF protein levels in the nAcc and medial preoptic area (MPOA) of high LG dams compared to low LG dams. In order to see if BDNF from the VTA can differentially influence the dopamine system in the nAcc of high and low LG dams, D3 receptor binding was evaluated in high and low LG dams. The results revealed no significant difference in D3 binding in high compared to low LG dams at PP4.
Conclusion
In summary, these findings suggest that variation in maternal care can lead to differences in the BDNF and dopamine system. (Supported by NIMH and CIHR).
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