, Volume 183, Issue 4, pp 482–489 | Cite as

Contribution of serotonin (5-HT) 5-HT2 receptor subtypes to the discriminative stimulus effects of cocaine in rats

  • Malgorzata Filip
  • Marcy J. Bubar
  • Kathryn A. CunninghamEmail author
Original Investigation



The serotonin (5-hydroxytryptamine; 5-HT) 5-HT2 receptor (5-HT2R) family is an important regulator of the behavioral responsiveness to cocaine.


The present study is an analysis of the role of the 5-HT2R subtypes (5-HT2AR, 5-HT2BR, and 5-HT2CR) in the discriminative stimulus effects of cocaine.


Male Wistar rats were trained to discriminate cocaine (10 mg/kg) from saline in a two-lever, water-reinforced FR 20 task, and we investigated the ability of the 5-HT2AR antagonist 1(Z)-[2-(dimethylamino)ethoxyimino]-1(2-fluorophenyl)-3-(4-hydroxyphenyl)-2(E)-propene (SR 46349B), the 5-HT2BR antagonist N-(1-methyl-5-indolyl)-N′-(3-methyl-5-isothiazolyl) urea (SB 204741), and the 5-HT2CR antagonist [(+)-cis -4,5,7a,8,9,10,11,11a-octahydro-7H-10-methylindolo(1,7-bC)(2,6)naphthyridine (SDZ SER-082) to substitute for or to modulate the stimulus effects of cocaine.


Pretreatment with SR 46349B (0.5–1 mg/kg) resulted in a rightward shift of the cocaine dose–response curve, while SDZ SER-082 (1 mg/kg) shifted the dose–response for cocaine to the left; SB 204741 (1–3 mg/kg) was inactive.


Our pharmacological analyses of selective antagonists of 5-HT2AR, 5-HT2BR, and 5-HT2CR indicate oppositional influence of 5-HT2AR and 5-HT2CR on the stimulus effects of cocaine and exclude a role for the 5-HT2BR. These data suggest that 5-HT2AR and 5-HT2CR may be important in modulating the subjective effects of cocaine in humans.


Serotonin receptors Drug discrimination SB 204741 SDZ SER-082 SR 46349B 



This research was supported by grants from the US–Poland Joint Commission Maria Sklodowska Curie Fund (MF and KAC), the National Institute on Drug Abuse [DA 06511 (KAC), DA 00260 (KAC), DA 15259 (MJB)], and the statutory activity of the Institute of Pharmacology Polish Academy of Sciences in Crakow (MF). The authors gratefully acknowledge the technical assistance of Ms. Ewa Nowak.


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Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Malgorzata Filip
    • 1
  • Marcy J. Bubar
    • 2
  • Kathryn A. Cunningham
    • 2
    Email author
  1. 1.Institute of PharmacologyPolish Academy of SciencesCracowPoland
  2. 2.Department of Pharmacology and Toxicology, Center for Addiction ResearchUniversity of Texas Medical BranchGalvestonUSA

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