Dr Volko Straub

Research Interests and Techniques

I am interested in the study of intrinsic neuronal properties and their short and long-term modulation with a particular emphasis on the neuromodulatory role of nitric oxide and serotonin. My work concentrates on two major questions:

• Metamodulation of serotonergic effects on neuronal and synaptic properties by nitric oxide, and its consequences

• The role of nitric oxide in long-term neuronal plasticity; in particular, its role in the induction of morphological changes that are associated with memory formation, the intracellular signalling pathways that lead to these changes and their effects on cellular, synaptic and network function

I study these questions using a combination of behavioural, electrophysiological, pharmacological, imaging, molecular biology and cell culture techniques applied to an invertebrate model system, the pond snail Lymnaea stagnalis. The relatively simple organisation of the Lymnaea nervous system enables me to directly relate cellular changes to network function and behaviour.

Metamodulation of serotonergic effects by nitric oxide

Plasticity is essential for behavioural adaptations and is achieved by modulation of cellular and synaptic properties. Neuromodulatory systems can themselves be the target for modulation, an effect termed metamodulation. I am particularly interested in the effects of nitric oxide on the modulatory effects of serotonin as there is increasing evidence for a functional overlap between serotonin and nitric oxide. Both modulators affect a wide range of nervous system functions ranging from sensory integration to motor control and learning. Progress in the understanding of the role of nitric oxide and serotonin in these processes depends strongly on a more detailed understanding of the mechanisms of their interactions.

My work concentrates on the characterisation of the molecular pathways that mediate the interactions between serotonin and nitric oxide, and the effects of these interactions on cellular properties, synaptic function and behaviour. In the long-term, insights into these interactions could provide the basis for the development of new treatment strategies for psychopathological conditions (e.g. depression, hyper-aggressive behaviour) and other clinical conditions (e.g. migraine, irritable bowel syndrome, erectile dysfunction) that are affected by nitric oxide and serotonin.

Nitric oxide, neuronal growth and memory formation

Long-term memory formation involves the remodelling of existing synapses and the creation of novel synapses. These processes require neurones to undergo morphological changes, i.e. sprouting of new growth cones; extension and/or retraction of spines and processes; formation or removal of synapses. There is evidence for nitric oxide causing similar morphological changes in the developing nervous system, but its role in such changes during memory formation in the adult nervous system has yet to be investigated.

I study the effects of nitric oxide on morphology and synapse formation of identified adult Lymnaea neurons that play a role in learning and memory formation. I am also interested in the characterisation of the molecular signalling pathways that mediate these effects.

Research Group and Funding

Present group members

Rodrigo Bammann

Current funding

BBSRC Project Grant: Nitric Oxide, neuritogenesis and synaptogenesis 

Recent Publications

Straub VA, Grant J, O’Shea M, Benjamin PR (2006) Modulation of serotonergic neurotransmission by nitric oxide. J Neurophys. (in press)
Kemenes I, Straub VA, Nikitin ES, Staras K, O'Shea M, Kemenes G, Benjamin PR. (2006) Role of delayed nonsynaptic neuronal plasticity in long-term associative memory. Curr Biol. 16: 1269-79.

Straub VA, Kemenes I, O'Shea M, Benjamin PR. (2006) Associative memory stored by functional novel pathway rather than modifications of pre-existing neuronal pathways. J Neurosci. 26: 4139-46.

Arundell M, Patel BA, Straub VA, Allen MC, O Hare D, Parker K, Gard P, Yeoman MS (2006) Deficits in sensory detection contribute to aging in the feeding system of the snail, Lymnaea. Neurobiology of Aging, 27:1880-91.

Korneev S, Straub VA, Kemenes I, Korneeva E, Ott S, Benjamin PR, O’Shea M (2005) Timed and targeted differential regulation of NOS and antiNOS genes by reward conditioning leading to long-term memory formation. J Neurosci 25: 1188-1192.

Straub VA, Styles BJ, Ireland JS, O’Shea M, Benjamin PR (2004) Central localization of plasticity involved in appetitive conditioning in Lymnaea. Learning & Memory 11(6): 787-793.

Straub VA, Staras K, Kemenes G, Benjamin PR (2002) Endogenous and network properties of Lymnaea feeding central pattern generator interneurons. J Neurophysiol 88(4): 1569-83.

Korneev S, Kemenes I, Straub VA, Staras K, Korneeva E, Kemenes G, Benjamin PR, O’Shea M (2002) Suppression of an NO-dependent behavior by dsRNA-mediated silencing of a nNOS gene. J Neurosci 2002 22: RC227.

Perry SJ, Straub VA, Schofield MG, Burke JF, Benjamin PR (2001) Neuronal expression of an FMRFamide-gated Na+ channel and its modulation by acid pH. J Neurosci 21(15): 5559-67.

Straub VA, Benjamin PR (2001) Extrinsic modulation and motor pattern generation in a feeding network: a cellular study. J Neurosci 21(5): 1767-78.

Park JH, Straub VA, O Shea M (1998) Anterograde signalling by nitric oxide: characterization and in vitro reconstitution of an identified nitrergic synapse. J Neurosci 18(14): 5463-76.

Perry SJ, Straub VA, Kemenes G, Santama N, Worster BM, Burke JF, Benjamin PR (1998) Neural modulation of gut motility by myomodulin peptides and acetylcholine in the snail Lymnaea. J Neurophysiol 79(5): 2460-74.

Peschel M, Straub V, Teyke T (1996) Consequences of food-attraction conditioning in Helix: A behavioral and electrophysiological study. J Comp Physiol A 178 (3): 317-327.