Figure 1
(a) Experimental timeline for microdialysis experiment, examining the effects of neurotoxic lesions in the medial preoptic area (mPOA) on cocaine-induced release of dopamine (DA) in the nucleus accumbens (NAc). (b) Representative micrograph depicting unilateral lesions of the mPOA, lesion side is on the right and intact side is on the left of the picture. Lesions were verified using staining for NeuN, a neuronal nuclear antigen (scale bar is 500 μm; AC, anterior commissure; OCH, optic chiasm; V3, third ventricle). Representations of histological analyses of probe placement and lesions are depicted in panels c and d. (c) Coronal hemisections through the right side of the NAc (1.44–1.80 mm anterior to the bregma). Lines represent placement of microdialysis probe in sham- and N-methyl-D-aspartate (NMDA)-lesioned animals. (d) Coronal hemisections through the mPOA (0.12 mm anterior to 1.08 mm posterior to the bregma). The largest acceptable lesions (shaded area) and smallest lesions (solid area) are shown, adapted from Paxinos et al (2007). (e) Graph summarizing results showing that mPOA lesions enhance cocaine-induced DA release. DA release changes in percent from baseline between sham-lesioned (n=12) and lesioned (n=9) female rats. Inset shows significant interaction (t(164)=2.94, p<0.01) between lesion and drug (saline and cocaine) collapsed across time. Values are expressed as mean±SEM. Differences between sham and lesioned subject: *<0.05; +=0.07. I.p., intraperitoneally.
