Research

Interests and techniques

My research is broadly centred on the study of neuromodulation, short- and long-term changes in neuronal networks and behavioural plasticity with a specific focus on the role of serotonin and nitric oxide. In this work, I try to integrate the use of both invertebrate (snails/slugs) and vertebrate model systems (dissociated cell and organotypic rat cortical cultures, acute brain slices) and use a range of techniques ranging from behavioural studies to electrophysiological, functional calcium imaging, immunohistochemistry and molecular methods.

Current main research projects are focused on:

Role of serotonergic signalling in cortical development

Serotonin is an important neuromodulatory signalling molecule in the central nervousCortical Culturesystem that has been linked to a range of conditions including depression, autism, schizophrenia and aggressive behaviour. Recent evidence suggests that some of the links are due to effects of serotonin during development of the central nervous system. In order to gain a better understanding of serotonin in cortical development, we study the effects of serotonergic signalling on neurite growth and synapse formation in cortical cell and organotypic cultures (Baliga et al, 2015; Baily et al, 2017; Picture: Rat primary cortical cell culture transfected with GFP [green] and stained for MAP2 [red]. The DNA dye Hoechst was used to visualise nuclei [blue]).

Interactions between serotonin signalling and stress in development of zebrafish CNS (collaboration with W Norton)

Early life stress and disruption of serotonergic signalling during development have both been shown to have negative impacts on behaviour in later life. In collaboration with the Norton lab, I have recently started to study whether early life stress affects serotonin signalling in developing zebrafish, and whether this is a possible link between early life stress and subsequent behavioural changes.

Additional/previous research projects:

Integration of sensory signalling pathways, learning and decision making in snails

Snail Food Preference LearningGastropods constitute a significant agricultural and horticultural pest around the world. This is in part due to their ability to rapidly adapt their food preference (Peschel et al., 1996), which makes them highly adaptive to changes in their environment and also very damaging as once they have 'acquired a taste' for a specific crop, they will feed selectively on that food source. This adaptive and flexible feeding strategy could also lead to active avoidance of molluscicide baits. Therefore, we have started a project to study the neuronal mechanisms that underlie the integration of chemosensory/olfactory signals (indicating the presence of a potential food source in the environment) and internal reward signals (providing feedback about the nutritional status of a food source), and how they interact to modify decision making. This project may provide important leads for the development of novel control strategies for gastropod pests with potentially less environmental impact than the common current practice of large scale molluscicide use.

Serotonergic modulation of cellular properties

Serotonin is a known modulator of intrinsic properties of both molluscan and mammalian neurons. I have previously shown that serotonin can induce conditional bursting and enhance post inhibitory rebound properties in the B4 buccal neuron of Lymnaea stagnalis (Straub & Benjamin, 2001). It also increases B4 excitability and more recently we have been studying its effects on specific voltage-gated potassium currents. We also carried out related studies in mammalian cortical neurons (Bammann et al, 2012).

Interactions between serotonin and nitric oxide

Colocalisation of serotonin and nitric oxide synthase has been described in various neurons including the Lymnaea cerebral giant cell (CGC) that provides the serotonergic input to the B4 neuron. Studying the effects of nitrergic signalling on B4 neurons revealed that nitric oxide enhances the postsynaptic effect of serotonin (Straub et al, 2007; Straub et al, 2013). We also explored whether nitric oxide can also modulate serotonergic responses in mammalian cortical neurons (Bammann et al, 2013; Straub et al, 2014).

Nitric oxide, neuritogenesis and synapse formation

Pic_Morphology_LymneaLong-term memory formation involves the remodeling of existing synapses and the creation of novel synapses. These processes require neurons to undergo morphological changes, i.e. sprouting of new growth cones; extension and/or retraction of spines and processes; formation or removal of synapses. Previous work has demonstrated that nitric oxide plays a significant role in learning and memory formation in Lymnaea (Korneev et al, 2002, 2005, Kemenes et al, 2006), similar to its role in other vertebrate and invertebrate species. In order to study whether endogenous nitric oxide can affect neuronal growth and synapse formation in adult neurons, we studied the effect of nitric oxide signaling on neuronal regeneration and synaptic re-modeling following axonal injury of identified Lymnaea B1 and B2 neurons. This enabled us to demonstrate that nitric oxide significantly modulates both neuronal growth and synaptic re-modelling (Cooke et al, 2013).

Identification and characterisation of purinergic P2X receptors in invertebrates (collaboration with S Ennion)

ATP sensitive purine receptors have been characterised extensively in vertebrates, but relatively little work had been conducted in invertebrate species. We cloned and characterised P2X receptors from Lymnaea (Bavan et al, 20111, 2012) and the tardigrade Hypsibius dujardini (Bavan et al, 2009).

Lab Members

Current:

  • Zoe Baily
  • Hari Sapkota

Previous:

  • David Lorincz
  • Rodrigo Bammann
  • Rebekah George
  • Vasco Claro
  • Raghav Baliga
  • Waheeda Nasreen
  • Selvan Bavan
  • Dr Ria Cooke

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Department of Neuroscience, Psychology and Behaviour
University of Leicester
University Road
Leicester
LE1 7RH

T: +44 (0)116 252 2922
E: npbenquiries@le.ac.uk

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