An investigation into mRNA expression in the rat pup olfactory bulb after odor preference learning.

Nartey, Michaelina Naadu (2014) An investigation into mRNA expression in the rat pup olfactory bulb after odor preference learning. Masters thesis, Memorial University of Newfoundland.

[English] PDF (Migrated (PDF/A Conversion) from original format: (application/pdf)) - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (2MB) [English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. (Original Version)

Abstract

Neonate rat pups rely on odor cues to identify their mother for food and warmth. Olfactory learning modifies behavioral, neural and metabolic responses to odor after a subsequent presentation with 24 h memory being dependent on CREB phosphorylation (pCREB). However the mRNA dependent changes that take place after olfactory learning have not been studied. Our lab previously showed that there is increased pCREB localization in the dorsolateral quadrant of mitral cells of the learning pups (odor + tactile stimulation) compared to the non-learning pups (odor only). In the present study, odor + stroking and odor only groups of pups were used. Following 10 minutes of training, pups were killed, and mRNA from the dorsolateral and ventromedial quadrants of the mitral cell layer was isolated using the laser microdissection (LMD) system for analyses by microarray. Thirteen genes with a minimum of a 1.5- fold difference in expression levels between groups were then analyzed using quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Six of the 13 genes showed concordance between microarray and qRT-PCR. Seven genes showed opposite expression patterns. A second study compared gene expression between whole bulb and LMD samples and a third study utilized qRT-PCR in whole bulbs to analyze the expression of the 13 genes at various times post training. Several of the genes confirmed as changing with learning are known to be involved in plasticity related activities, but were not previously associated with olfactory learning and memory formation. These findings will form an important basis for conducting further studies that will help us understand olfactory learning better.

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