The formation of mate recognition memory in female mice is dependent on enhanced noradrenaline release within the accessory olfactory bulb (AOB), stimulated by mating, and the exposure to the mating male's pheromonal signals. Memory formation is associated with an enhancement of inhibition at a reciprocal dendrodendritic synapse between excitatory mitral/tufted cells and inhibitory granule cells, however the exact mechanism by which noradrenaline facilitates the formation of memory is unknown. This thesis aimed to further investigate the noradrenergic modulation of the AOB in the context of mate recognition memory using electrophysiological recording from anaesthetised female mice. Artificial vaginocervical stimulation caused heterogeneous short- and long-term changes in the firing rate of spontaneously active mitral/tufted cells, consistent with the enhanced neuromodulation of the AOB during mating. However, inconsistent responses observed across multiple exposures to different types of dilute urine in combination with unexpected responses to control solutions following application of stimulus solution to the nose and electrical stimulation of the sympathetic nerve trunk suggested that stimulus-evoked mitral/tufted cell activity could not be driven reliably. Therefore, despite the apparent success in developing a model of mating in anaesthetised female mice, further attempts to develop an experimental protocol for the induction of mate recognition memory were hindered. Immunohistochemical staining showed a potentially distinct distribution of the 6 aadrenoceptor subtypes throughout the laminar structure of the AOB and the application of the a2-adrenoceptor agonist, cionidine, to the recording probe craniotomy above the olfactory bulb caused an unexpected decrease in mitral/tufted cell firing rate. These findings suggest a possible action of noradrenaline in different layers of the AOB aside from the previously reported modulation of the mitral/tufted cell:granule cell synapse and emphasise the need for more targeted approaches for investigating the contribution of different aadrenoceptor subtypes in the modulation of neuronal network activity within the AOB
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:687183 |
| Date | January 2015 |
| Creators | Griffiths, Philip |
| Publisher | University of Bristol |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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