Nomifensine amplifies subsecond dopamine signals in the ventral striatum of freely-moving rats
Version of Record online: 5 JUL 2004
Journal of Neurochemistry
Volume 90, Issue 4, pages 894–903, August 2004
How to Cite
Robinson, D. L. and Wightman, R. M. (2004), Nomifensine amplifies subsecond dopamine signals in the ventral striatum of freely-moving rats. Journal of Neurochemistry, 90: 894–903. doi: 10.1111/j.1471-4159.2004.02559.x
- Issue online: 5 JUL 2004
- Version of Record online: 5 JUL 2004
- Received February 4, 2004; revised manuscript received April 13, 2004; accepted April 16, 2004.
- dopamine transporter;
- nucleus accumbens;
- olfactory tubercle;
The present experiment examined the effect of the dopamine transporter blocker nomifensine on subsecond fluctuations in dopamine concentrations, or dopamine transients, in the nucleus accumbens and olfactory tubercle. Extracellular dopamine was measured in real time using fast-scan cyclic voltammetry at micron-dimension carbon fibers in freely-moving rats. Dopamine transients occurred spontaneously throughout the ventral striatum in the absence of apparent sensory input or change in behavioral response. The frequency of dopamine transients increased at the presentation of salient stimuli to the rat (food, novel odors and unexpected noises). Administration of 7 mg/kg nomifensine amplified spontaneous dopamine transients by increasing both amplitude and duration, consistent with its known action at the dopamine transporter and emphasizing the dopaminergic origin of the signals. Moreover, nomifensine increased the frequency of detected dopamine transients, both during baseline conditions and at the presentation of stimuli, but more profoundly in the nucleus accumbens than in the olfactory tubercle. This difference was not explained by nomifensine effects on the kinetics of dopamine release and uptake, as its effects on electrically-evoked dopamine signals were similar in both regions. These findings demonstrate the heterogeneity of dopamine transients in the ventral striatum and establish that nomifensine elevates the tone of rapid dopamine signals in the brain.