TABLE 2

Effects of i.m. drug pretreatments on overall response rates under the concurrent fixed-ratio 30 schedules of i.v. injections and food delivery during i.v. saline availability Drugs are grouped into monoamine transport inhibitors, dopamine D1 agonists, and dopamine D2 agonists. Each entry represents the mean value (±S.E.M.) of response rates (responses/second) in three or four monkeys during the 30-min session component following injection of vehicle or of the listed dose of drug. Control values (±S.E.M.) for the effects of each drug are shown under vehicle (Veh) and were obtained for each drug by averaging the effects of saline pretreatment across at least three sessions of i.v. saline availability during the time that drug was tested. Effects of drugs on response distribution and reinforcer delivery are plotted in Figs. 1 and (2


Drug

Pretreatment Dose (mg/kg)

Veh
0.03
0.1
0.32
1.0
3.2
10

Transport inhibitors
   Cocaine 1.9 ± 0.5 2.0 ± 0.9 2.0 ± 0.8 0.9 ± 0.5 0.2 ± 0.1
   GBR 12909 2.0 ± 0.5 2.6 ± 0.6 2.3 ± 0.6 1.7 ± 0.8 1.4 ± 1.4
   Citalopram 2.0 ± 0.7 1.8 ± 1.0 1.6 ± 0.6 1.1 ± 0.6 0.7 ± 0.4
   Desipramine 2.5 ± 0.5


2.1 ± 0.8
1.9 ± 0.8
0.8 ± 0.2
0.01
0.03
0.1
0.32
1.0
D1 agonists
   SKF 82958 2.3 ± 0.4 2.2 ± 0.5 1.5 ± 0.6 0.7 ± 0.4
   R-(+)-6BrAPB 2.1 ± 0.5 2.4 ± 0.6 1.6 ± 0.8 1.5 ± 0.3 0.9 ± 0.4 1.0 ± 0.6
   SKF 83959 2.4 ± 0.6

1.8 ± 0.005
1.0 ± 0.7
0.7 ± 0.4


0.0003
0.001
0.003
0.01
0.03
0.1
0.32
D2 agonists
   Quinelorane 2.4 ± 0.6 2.4 ± 0.5 1.8 ± 0.6 1.2 ± 0.4 0.7 ± 0.4 0.6 ± 0.2
   R-NPA 2.1 ± 0.6 2.7 ± 0.6 2.0 ± 0.8 1.4 ± 0.7 0.7 ± 0.5 0.7 ± 0.5a
   (+)-PHNO 2.1 ± 0.7 1.8 ± 0.6 1.3 ± 0.7 0.5 ± 0.2 0.4 ± 0.2
   PD 128907
2.3 ± 0.5



2.2 ± 0.5
1.1 ± 0.4
1.1 ± 0.5
1.0 ± 0.4
  • a The effects of this cumulative dose were determined only in monkeys Mm 258 and Mm 331 because responding was completely eliminated in monkeys Mm 263 and Mm 211 following the cumulative dose of 0.01 mg/kg R-NPA