Our results thus allow to extend the sphere of influence of LXR to human circulating neutrophils

ediolateral and dorsoventral are given in mm. The stimulating electrode targeted the medial forebrain bundle, and a CFM targeted the dorsal and ventral striatum. The reference electrode, a chloridized silver wire, was placed in the contralateral superficial cortex. Electrochemistry FSCV was performed by a Universal Electrochemistry Instrument, which was computer controlled by commercially available software. The potential of the CFM was linearly scanned at 10 Hz from a resting value of 20.4 V to 1.3 V and back again at a rate of 400 V/s. The peak oxidation current for dopamine GS 1101 recorded during each scan was converted to a concentration based on post-calibration of the CFM using flow-injection analysis in a buffer consisting of 150 mM sodium chloride with 15 mM TRIS and adjusted to a pH of 7.4. Dopamine was identified from the background subtracted voltammogram. Electrical Stimulation Electrical stimulation was computer generated and consisted of biphasic pulses. Stimulus trains were applied to a twisted bipolar stimulating electrode through a constant-current generator and optical isolator. Animals Adult male Sprague-Dawley rats, purchased from Harlan, were housed under standard conditions of lighting and temperature. Food and water were provided ad libitum. Protocols were approved by the Institutional Animal Care and Use Committee of Illinois State University. Care was in accordance with NIH guidelines. Data Analysis Surgery Rats were anesthetized with urethane and immobilized in a stereotaxic frame, indicated by the horizontal line under each evoked response, were applied before and after psychostimulant administration at time 0 min. Note that evoked responses are on a second timescale, while the overall design is shown in minutes. doi:10.1371/journal.pone.0060763.g001 where 22112465 p is the concentration of dopamine released per stimulus pulse, f is the frequency of stimulation, and k is 21793044 the firstorder term describing dopamine uptake. Data were best fit to Equation 1 using non-linear regression with a simplex algorithm. First-order, as opposed to Michaelis-Menten, kinetics was selected to characterize dopamine uptake because of concern that AMPH alters both Km and Vmax, which is difficult to resolve with in vivo voltammetry. However, similar AMPH-induced changes in p, the focus of the present study, have been reported using both kinetic models. Dopamine responses evoked by long trains were analyzed for vesicular dopamine release using single curve analysis. The reason is that Equation 1 assumes that vesicular dopamine release is constant, and AMPH clearly caused time-dependent changes in recordings evoked by long trains as evident by the pronounced slowing of the upward slope during the train, especially in the dorsal striatum. In single curve analysis, which does not assume a kinetic mechanism Amphetamine Effects on Dopamine Pools The only assumption of single curve analysis regarding uptake is that rates governing up- and downward portions are identical at the same dopamine concentration, which is also the same assumption as in Equation 1. It should be emphasized that because of DAT reversal, uptake measured in the presence of AMPH more faithfully represents net dopamine clearance, i.e., the difference between extracellular removal by uptake and addition by efflux. Nevertheless, the combination of these effects is accounted for in the analysis, which permits a direct determination of vesicular dopamine release. Non-electrically evoked chang