Figure 4.

Effects of MDPV and cocaine on extracellular dopamine in nucleus accumbens, locomotor activity and cardiovascular parameters in conscious rats. For microdialysis studies (a, b), rats received i.v. injection of MDPV (a) or cocaine (b) at time zero (see t=0-min arrows), followed by a threefold higher dose 60 min later (see 60-min arrows). Vehicle controls received i.v. saline injections on the same time schedule. Dialysate DA data are percentage of basal expressed as mean±s.e.m. for N=6–7 rats/group. *P<0.05 compared with saline vehicle at a particular time point (Bonferroni's test). For locomotor studies (c, d), rats received s.c. injection of MDPV, cocaine, or saline vehicle and were placed into chambers equipped with photobeams. Distance traveled (c) and stereotypic movements (d) were measured for 1 h post-injection. Data are mean±s.e.m. for N=6–7 test sessions/dose. *P<0.05 compared with saline-treated control (Newman–Keuls test). For the cardiovascular measurements (e, f), rats bearing surgically implanted telemetric sensors received s.c. injection of MDPV, cocaine, or saline vehicle. Heart rate (e) and blood pressure (f) were measured for 2 h post-injection. Data are mean±s.e.m. for N=6–7 test sessions/dose. *P<0.05 compared with saline-treated control (Newman–Keuls test).