TY - JOUR
T1 - Stimulation of 5-HT1B receptors enhances cocaine reinforcement yet reduces cocaine-seeking behavior
T2 - PRECLINICAL STUDY
AU - Pentkowski, Nathan S.
AU - Acosta, Jazmin I.
AU - Browning, Jenny R.
AU - Hamilton, Elizabeth C.
AU - Neisewander, Janet
PY - 2009/10
Y1 - 2009/10
N2 - Paradoxically, stimulation of 5-HT1B receptors (5-HT 1BRs) enhances sensitivity to the reinforcing effects of cocaine but attenuates incentive motivation for cocaine as measured using the extinction/reinstatement model. We revisited this issue by examining the effects of a 5-HT1BR agonist, CP94253, on cocaine reinforcement and cocaine-primed reinstatement, predicting that CP94253 would enhance cocaine-seeking behavior reinstated by a low priming dose, similar to its effect on cocaine reinforcement. Rats were trained to self-administer cocaine (0.75 mg/kg, i.v.) paired with light and tone cues. For reinstatement experiments, they then underwent daily extinction training to reduce cocaine-seeking behavior (operant responses without cocaine reinforcement). Next, they were pre-treated with CP94253 (3-10 mg/kg, s.c.) and either tested for cocaine-primed (10 or 2.5 mg/kg, i.p.) or cue-elicited reinstatement of extinguished cocaine-seeking behavior. For reinforcement, effects of CP94253 (5.6 mg/kg) across a range of self-administered cocaine doses (0-1.5 mg/kg, i.v.) were examined. Cocaine dose-dependently reinstated cocaine-seeking behavior, but contrary to our prediction, CP94253 reduced reinstatement with both priming doses. Similarly, CP94253 reduced cue-elicited reinstatement. In contrast, CP94253 shifted the self-administration dose-effect curve leftward, consistent with enhanced cocaine reinforcement. When saline was substituted for cocaine, CP94253 reduced response rates (i.e. cocaine-seeking behavior). In subsequent control experiments, CP94253 decreased open-arm exploration in an elevated plus-maze suggesting an anxiogenic effect, but had no effect on locomotion or sucrose reinforcement. These results provide strong evidence that stimulation of 5-HT1BRs produces opposite effects on cocaine reinforcement and cocaine-seeking behavior, and further suggest that 5-HT1BRs may be a novel target for developing medications for cocaine dependence.
AB - Paradoxically, stimulation of 5-HT1B receptors (5-HT 1BRs) enhances sensitivity to the reinforcing effects of cocaine but attenuates incentive motivation for cocaine as measured using the extinction/reinstatement model. We revisited this issue by examining the effects of a 5-HT1BR agonist, CP94253, on cocaine reinforcement and cocaine-primed reinstatement, predicting that CP94253 would enhance cocaine-seeking behavior reinstated by a low priming dose, similar to its effect on cocaine reinforcement. Rats were trained to self-administer cocaine (0.75 mg/kg, i.v.) paired with light and tone cues. For reinstatement experiments, they then underwent daily extinction training to reduce cocaine-seeking behavior (operant responses without cocaine reinforcement). Next, they were pre-treated with CP94253 (3-10 mg/kg, s.c.) and either tested for cocaine-primed (10 or 2.5 mg/kg, i.p.) or cue-elicited reinstatement of extinguished cocaine-seeking behavior. For reinforcement, effects of CP94253 (5.6 mg/kg) across a range of self-administered cocaine doses (0-1.5 mg/kg, i.v.) were examined. Cocaine dose-dependently reinstated cocaine-seeking behavior, but contrary to our prediction, CP94253 reduced reinstatement with both priming doses. Similarly, CP94253 reduced cue-elicited reinstatement. In contrast, CP94253 shifted the self-administration dose-effect curve leftward, consistent with enhanced cocaine reinforcement. When saline was substituted for cocaine, CP94253 reduced response rates (i.e. cocaine-seeking behavior). In subsequent control experiments, CP94253 decreased open-arm exploration in an elevated plus-maze suggesting an anxiogenic effect, but had no effect on locomotion or sucrose reinforcement. These results provide strong evidence that stimulation of 5-HT1BRs produces opposite effects on cocaine reinforcement and cocaine-seeking behavior, and further suggest that 5-HT1BRs may be a novel target for developing medications for cocaine dependence.
KW - CP94253
KW - Extinction
KW - Motivation
KW - Reinstatement
KW - Relapse
KW - Sucrose reinforcement
UR - http://www.scopus.com/inward/record.url?scp=70049109658&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=70049109658&partnerID=8YFLogxK
U2 - 10.1111/j.1369-1600.2009.00162.x
DO - 10.1111/j.1369-1600.2009.00162.x
M3 - Article
C2 - 19650818
AN - SCOPUS:70049109658
SN - 1355-6215
VL - 14
SP - 419
EP - 430
JO - Addiction Biology
JF - Addiction Biology
IS - 4
ER -