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Differential involvement of dopamine in mediating the discriminative stimulus effects of low and high doses of caffeine in rats.
Behav Pharmacol. 1999 Dec; 10(8):707-16.BP

Abstract

The hypothesis that low and high doses of caffeine produce effects that are differentially mediated by dopamine (DA) receptor mechanisms was investigated in rats trained to discriminate either 10 or 56 mg/kg of caffeine from saline. Rats trained to discriminate 56 mg/kg of caffeine acquired the discrimination in an average of 74 sessions, whereas rats trained to discriminate 10 mg/kg of caffeine required an average of 108 sessions. The DA D1 receptor agonist SKF 81297 and the DA D2 receptor agonist R(-)-propylnorapomorphine (NPA) generalized partially (50-75%) in rats trained to discriminate 10 mg/kg of caffeine, but produced predominantly saline-appropriate responding (< 40%) in rats trained to discriminate 56 mg/kg of caffeine. When SKF 81297 and NPA were combined, stimulus generalization was no greater than it was when either agonist was tested alone. The DA uptake inhibitors cocaine and GBR 12909 produced predominantly saline-appropriate responding in both groups of rats. Neither the DA D1 receptors antagonists SCH 23390 and SCH 31966, nor the DA D2 receptor antagonists eticlopride and sulpiride, generalized in rats trained to discriminate 10 or 56 mg/kg of caffeine. When administered in combination with caffeine, both the DA D1 and DA D2 antagonists antagonized completely the discriminative stimulus effects of the low training dose of caffeine, but did not alter the discriminative stimulus effects of the high training dose. These results suggest that the discriminative stimulus effects of 10 mg/kg of caffeine, but not 56 mg/kg of caffeine, are dependent on, but not limited to, DA D1 and D2 receptor mechanisms.

Authors+Show Affiliations

Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA. kpowell@leeuniversity.eduNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

10780285

Citation

Powell, K R., et al. "Differential Involvement of Dopamine in Mediating the Discriminative Stimulus Effects of Low and High Doses of Caffeine in Rats." Behavioural Pharmacology, vol. 10, no. 8, 1999, pp. 707-16.
Powell KR, Koppelman LF, Holtzman SG. Differential involvement of dopamine in mediating the discriminative stimulus effects of low and high doses of caffeine in rats. Behav Pharmacol. 1999;10(8):707-16.
Powell, K. R., Koppelman, L. F., & Holtzman, S. G. (1999). Differential involvement of dopamine in mediating the discriminative stimulus effects of low and high doses of caffeine in rats. Behavioural Pharmacology, 10(8), 707-16.
Powell KR, Koppelman LF, Holtzman SG. Differential Involvement of Dopamine in Mediating the Discriminative Stimulus Effects of Low and High Doses of Caffeine in Rats. Behav Pharmacol. 1999;10(8):707-16. PubMed PMID: 10780285.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Differential involvement of dopamine in mediating the discriminative stimulus effects of low and high doses of caffeine in rats. AU - Powell,K R, AU - Koppelman,L F, AU - Holtzman,S G, PY - 2000/4/26/pubmed PY - 2000/5/20/medline PY - 2000/4/26/entrez SP - 707 EP - 16 JF - Behavioural pharmacology JO - Behav Pharmacol VL - 10 IS - 8 N2 - The hypothesis that low and high doses of caffeine produce effects that are differentially mediated by dopamine (DA) receptor mechanisms was investigated in rats trained to discriminate either 10 or 56 mg/kg of caffeine from saline. Rats trained to discriminate 56 mg/kg of caffeine acquired the discrimination in an average of 74 sessions, whereas rats trained to discriminate 10 mg/kg of caffeine required an average of 108 sessions. The DA D1 receptor agonist SKF 81297 and the DA D2 receptor agonist R(-)-propylnorapomorphine (NPA) generalized partially (50-75%) in rats trained to discriminate 10 mg/kg of caffeine, but produced predominantly saline-appropriate responding (< 40%) in rats trained to discriminate 56 mg/kg of caffeine. When SKF 81297 and NPA were combined, stimulus generalization was no greater than it was when either agonist was tested alone. The DA uptake inhibitors cocaine and GBR 12909 produced predominantly saline-appropriate responding in both groups of rats. Neither the DA D1 receptors antagonists SCH 23390 and SCH 31966, nor the DA D2 receptor antagonists eticlopride and sulpiride, generalized in rats trained to discriminate 10 or 56 mg/kg of caffeine. When administered in combination with caffeine, both the DA D1 and DA D2 antagonists antagonized completely the discriminative stimulus effects of the low training dose of caffeine, but did not alter the discriminative stimulus effects of the high training dose. These results suggest that the discriminative stimulus effects of 10 mg/kg of caffeine, but not 56 mg/kg of caffeine, are dependent on, but not limited to, DA D1 and D2 receptor mechanisms. SN - 0955-8810 UR - https://www.unboundmedicine.com/medline/citation/10780285/Differential_involvement_of_dopamine_in_mediating_the_discriminative_stimulus_effects_of_low_and_high_doses_of_caffeine_in_rats_ L2 - http://ovidsp.ovid.com/ovidweb.cgi?T=JS&amp;PAGE=linkout&amp;SEARCH=10780285.ui DB - PRIME DP - Unbound Medicine ER -