Measurement of extracellular potassium dynamics

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My research program investigates the effects of environmental stress on neural circuits that control crucial behaviours such as ventilation and escape. I am interested in the mechanisms that underlie how some animals are better able to handle stress. For instance, animals which have been exposed to a stressful situation subsequently develop tolerance to future stresses. This research is relevant to Canadians because it highlights the behavioural consequences that global warming may have on insects. For example prairie grasshoppers with increased tolerance to high temperatures may spread further and have a greater impact on crops. In order to control these behaviours at high temperatures, neurons must regulate the ionic concentrations of specific ions inside and outside the neurons. At high temperatures these gradients break down. Animals that have received a prior exposure to stress are better able to maintain these ionic gradients during subsequent exposures to stress. Although many ions are crucial for proper neural function, potassium is of particular interest. Potassium ions usually reside inside the neuron, but at a critical point when the temperature exceeds the ability of the cell to maintain this gradient a massive and debilitating release of potassium ensues. When this happens neurons and the behaviours they control cease to function. We are interested in what regulates this release of potassium. To accomplish this we must use equipment that measures ionic concentrations inside and outside the cell. I am requesting funding to purchase equipment that will enable my students and me to measure the dynamics of extracellular potassium in relation to appropriate function of the neural circuit that controls ventilation in locusts.