Pretreatment | A Final Preinjection | B Peak Postinjection | C Absolute Change | D Change |
---|---|---|---|---|
% | ||||
Extracellular DA | ||||
Saline | 85.7 ± 8.2 | 151.7 ± 17.9 | 66.0 ± 15.3 | 79.8 ± 18.1 |
10 mg/kg 4-Cl-BZT | 94.6 ± 24.5 | 154.6 ± 31.1 | 60.0 ± 8.7 | 77.2 ± 16.2 |
40 mg/kg 4-Cl-BZT | 284.5 ± 81.7 | 398.1 ± 104.4 | 113.6 ± 25.9 | 43.7 ± 5.3 |
Cocaine | 95.6 ± 11.9 | 139.1 ± 6.7 | 43.5 ± 10.4 | 48.8 ± 14.8 |
Locomotor activity | ||||
Saline | 224 ± 33 | 1384 ± 398 | 1160 ± 398 | 647.1 ± 257.4 |
10 mg/kg 4-Cl-BZT | 368 ± 86 | 2920 ± 1389 | 2552 ± 1376 | 741.1 ± 337.9 |
40 mg/kg 4-Cl-BZT | 2809 ± 534 | 7273 ± 977 | 4464 ± 1183 | 218.6 ± 70 |
Cocaine | 1927 ± 566 | 1725 ± 291 | −202 ± 819 | 10.1 ± 38.2 |
Effects of i.p. pretreatment (2 hr before) on extracellular DA and locomotor response to a challenge injection of 10 mg/kg i.p. cocaine. Values for extracellular DA concentrations in dialysate fractions from NAc are means (±S.E.M.) and are expressed as fmol/20-μl sample. Values for locomotor activity are mean (±S.E.M.) photocell counts/15 min. Final preinjection values (column A) were collected during last time period before cocaine challenge and are reproduced from Fig. 2. Peak postinjection data (column B) represent highest absolute values after the 10-mg/kg cocaine injection (generally 15–45 min postinjection). Absolute change values (column C) represent difference between final preinjection and peak postinjection values. Percent change values (column D) were calculated for each rat as (postinjection − preinjection)/preinjection × 100. For all values, calculations were made for each individual animal and then averaged within each treatment group. The (−) sign associated with locomotor change in cocaine-pretreated rats indicates an average net lower locomotion after 10 mg/kg cocaine challenge than immediately before.