Egr-1 antisense oligodeoxynucleotide administration into the olfactory bulb impairs olfactory learning in the greater short-nosed fruit bat Cynopterus sphinx.

Ambigapathy Ganesh, Wieslaw Bogdanowicz, Krishnaswamy Balamurugan, Durairaj Ragu Varman, Koilmani Emmanuvel Rajan

Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620024, India.

Brain research 2012 Aug 30

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Postsynaptic densities (PSDs) contain proteins that regulate synaptic transmission. We examined two important examples of these, calcium/calmodulin-dependent protein kinase II (CaMKII) and PSD-95, in regard to the functional role of early growth response gene-1 (egr-1) in regulation of olfactory learning in the greater short-nosed fruit bat Cynopterus sphinx (family Pteropodidae). To test whether activation of egr-1 in the olfactory bulb (OB) is required for olfactory memory of these bats, bilaterally canulated individuals were infused with antisense (AS) or non-sense (NS)-oligodeoxynucleotides (ODN) of egr-1, or with phosphate buffer saline (PBS), 2h before the olfactory training. Our results showed that behavioral training significantly up-regulates immediate early gene (IEG) EGR-1 and key synaptic proteins Synaptotagmin-1(SYT-1), CaMKII and PSD-95, and phosphorylation of CaMKII in the OB at the protein level per se. Subsequently, we observed that egr-1 antisense-ODN infusion in the OB impaired olfactory memory and down regulates the expression of CaMKII and PSD-95, and the phosphorylation of CaMKII but not SYT-1. In contrast, NS-ODN or PBS had no effect on the expression of the PSDs CaMKII or PSD-95, or on the phosphorylation of CaMKII. When the egr-1 NS-ODN was infused in the OB after training for the novel odor there was no effect on olfactory memory. These findings suggest that egr-1 control the activation of CaMKII and PSD-95 during the process of olfactory memory formation. Copyright © 2012 Elsevier B.V. All rights reserved.

Citation

Ambigapathy Ganesh, Wieslaw Bogdanowicz, Krishnaswamy Balamurugan, Durairaj Ragu Varman, Koilmani Emmanuvel Rajan. Egr-1 antisense oligodeoxynucleotide administration into the olfactory bulb impairs olfactory learning in the greater short-nosed fruit bat Cynopterus sphinx. Brain research. 2012 Aug 30;1471:33-45