Figure 3.
a–f, Extracellular DA, DOPAC, and HVA in the nucleus accumbens during short-term (a–c) versus longer-term (d–f) haloperidol treatment. HAL initially increased baseline levels of DA and DOPAC (a, inset, b; 2-way ANOVAs on −120 to −20 min, main effects of condition, F = 13.82 and F = 9.15, respectively; p < 0.05), but DA and DOPAC levels became similar to those of controls with chronic treatment (d, inset, e). Basal HVA levels were not significantly affected by HAL on either testing day (c, f). An injection of saline did not alter analyte levels in either group on either test day. AMPH increased DA levels above saline in both groups and on both test days (2-way ANOVAs on −40 to 140 min, main effect of time, a, F = 13.30; d, F = 37.23; p < 0.0001). HAL had no significant effect on the DA response to AMPH on either test day (a, d, 2-way ANOVAs, condition by time, p = 0.78 and 0.70, respectively). In both groups and on both test days, AMPH decreased DOPAC (main effects of time, b, F = 29.82; e, F = 56.34; p < 0.0001) and HVA (c, F = 19.28; f, F = 56.17; p < 0.0001) levels relative to saline. Initially, HAL did not alter these responses (condition by time, b, p = 0.81; c, p = 0.90), but chronic HAL treatment attenuated the AMPH-induced decrease in DOPAC and HVA (condition by time, e, F = 7.99; f, F = 11.27; p < 0.0001). n = 7–8 per condition per time point. Error bars indicate SEM.