Jill VentonJill Venton

Analytical Neurochemistry

I am interested in the development and characterization of analytical techniques to measure neurochemical changes. Measurements in the brain are challenging because zeptomole quantities of neuroactive molecules must be detected in a chemically-complex sample while disturbing the tissue as little as possible. In addition, fast time resolution measurements are needed to track the fast dynamics of neurotransmitter release and uptake. The development of new analytical tools will enable a better understanding of the central nervous system which will, in turn, facilitate the development of new treatments for neurological disorders.

Electrochemical Detection of Adenosine
The goal of this project is to develop an electrochemical detection method for real-time monitoring of adenosine concentrations. Adenosine is a neuromodulator in the brain that has a variety of actions including regulation of cerebral blood flow, modulation of neurotransmission, and protection against neuronal injury during stroke. There is currently no reliable method for electrochemical detection of adenosine in vivo. Direct detection of adenosine using cyclic voltammetry at carbon-fiber microelectrodes will be examined as well as using electrodes modified with electron mediators. The sensor will be used to characterize extracellular adenosine release in the rat brain following electrical stimulation of neuronal activity and during ischemia, a model of stroke. Simultaneous monitoring of adenosine, oxygen and dopamine concentrations will allow studies of how adenosine modulates neurotransmission and cerebral blood flow. Finally, a finite difference model of adenosine diffusion will be constructed to examine the factors that control adenosine concentrations.

Mechanisms of Drugs of Abuse using Capillary Electrophoresis
My second proposal is directed at the development of separation methods to study new molecules in microdialysate samples with capillary electrophoresis with laser-induced fluorescence detection. Currently, only 6 amino acid neurotransmitters are routinely monitored with high temporal resolution. First, a separation will be optimized to detect amphetamine, a drug of abuse, and amino acids simultaneously. Microdialysis will be used to examine the effects of dose and the route of amphetamine administration on the pharmacokinetics (the dynamics of drug concentrations) and pharmacodynamics (the effects on neurotransmitter concentrations). Different fluorescent tags will be examined to study secondary amines such as Ecstasy.

Representative Publications

B.J. Venton, R.T. Kennedy, T.E. Robinson, S. Maren. Dynamic increases in glutamate and GABA in the basolateral amygdala during acquisition and expression of conditioned fear. European Journal of Neuroscience,
2006, 12, 3391-3398.

B.J. Venton, P.E.M. Phillips, W.C. Wetsel, D. Gitler, G. Augustine, P. Greengard, R.M. Wightman. Cocaine increases dopamine release by mobilization of a synapsin-dependent reserve pool. Journal of Neuroscience, 2006, 26, 3206-3209/./

B.J. Venton, T.E. Robinson, R.T. Kennedy. Transient changes in nucleus accumbens amino acid concentrations correlate with individual responsivity to the predator fox odor 2,5-dihydro-2,4,5-trimethylthiazoline. Journal of Neurochemistry, 2006, 96, 236-246.

B.J. Venton, H. Zhang, P.A. Garris, D. Sulzer, P.E.M. Phillips, R.M. Wightman. Real-time decoding of dopamine neurotransmission in the caudate-putamen during tonic and phasic firing. Journal of Neurochemistry, 2003, 87, 1284-1295.

B.J. Venton and R.M. Wightman. Psychoanalytical electrochemistry: dopamine and behavior. Analytical Chemistry, 2003, 75, 414A-421A.

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