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Effects of selective dopamine D1- and D2-type receptor antagonists on the development of behavioral sensitization to 7-OH-DPAT.
Psychopharmacology (Berl). 1998 Dec; 140(4):387-97.P

Abstract

The primary objective of this study was to determine whether the development of behavioral sensitization to the putative dopamine D3 receptor agonist 7-OH-DPAT could be prevented by either selective D1-type or D2-type dopamine receptor antagonists. In three experiments, male Wistar rats (250-350 g) were given seven to nine injections (at 48-h intervals) of 7-OH-DPAT (1.0 mg/kg, SC) or vehicle in combination with the D2-type dopamine antagonist eticlopride (0.3 mg/kg, SC), the D1-type dopamine antagonist SCH 23390 (0.1 or 0.2 mg/kg, SC), or vehicle. After the injections, the rats were tested for locomotor activity in photocell arenas for 2 h. In the first two experiments, after seven injections, all rats were tested for activity following vehicle injections to test for possible conditioning effects. In each experiment, after the last pre-exposure session, all rats were given a challenge injection of 7-OH-DPAT (1.0 mg/kg, SC) and tested for activity. Major findings were as follows: a) 7-OH-DPAT treatments produced a progressively greater increase in locomotor activity with repeated treatment; b) concurrent treatment with eticlopride or SCH 23390 (0.1 and 0.2 mg/kg) blocked the acute locomotor-activating effects of 7-OH-DPAT across days; c) eticlopride, but not SCH 23390, completely blocked the development of behavioral sensitization to 7-OH-DPAT. Although the low dose of SCH 23390 (0.1 mg/kg) produced a partial attenuation of sensitization, the higher dose (0.2 mg/kg) of SCH 23390 appeared to augment, rather than block, sensitization to 7-OH-DPAT; d) rats previously treated with SCH 23390 (0.2 mg/kg, but not 0.1 mg/kg) without 7-OH-DPAT displayed a hyperactive response to the 7-OH-DPAT challenge injection; and e) after vehicle injections, rats previously given 7-OH-DPAT, SCH 23390, or eticlopride either alone or in combination were more active than vehicle control rats. These findings suggest that the neurochemical mechanisms mediating the development of behavioral sensitization to 7-OH-DPAT may differ from those of other dopamine D2-type agonists such as quinpirole or bromocriptine. Moreover, these results demonstrate that hyperactivity responses following vehicle injections in drug-pretreated animals do not necessarily reflect conditioning mechanisms.

Authors+Show Affiliations

Department of Psychology, Morehead State University, KY 40351-1689, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

9888612

Citation

Mattingly, B A., et al. "Effects of Selective Dopamine D1- and D2-type Receptor Antagonists On the Development of Behavioral Sensitization to 7-OH-DPAT." Psychopharmacology, vol. 140, no. 4, 1998, pp. 387-97.
Mattingly BA, Himmler C, Bonta T, et al. Effects of selective dopamine D1- and D2-type receptor antagonists on the development of behavioral sensitization to 7-OH-DPAT. Psychopharmacology (Berl). 1998;140(4):387-97.
Mattingly, B. A., Himmler, C., Bonta, T., & Rice, L. L. (1998). Effects of selective dopamine D1- and D2-type receptor antagonists on the development of behavioral sensitization to 7-OH-DPAT. Psychopharmacology, 140(4), 387-97.
Mattingly BA, et al. Effects of Selective Dopamine D1- and D2-type Receptor Antagonists On the Development of Behavioral Sensitization to 7-OH-DPAT. Psychopharmacology (Berl). 1998;140(4):387-97. PubMed PMID: 9888612.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effects of selective dopamine D1- and D2-type receptor antagonists on the development of behavioral sensitization to 7-OH-DPAT. AU - Mattingly,B A, AU - Himmler,C, AU - Bonta,T, AU - Rice,L L, PY - 1999/1/15/pubmed PY - 1999/1/15/medline PY - 1999/1/15/entrez SP - 387 EP - 97 JF - Psychopharmacology JO - Psychopharmacology (Berl) VL - 140 IS - 4 N2 - The primary objective of this study was to determine whether the development of behavioral sensitization to the putative dopamine D3 receptor agonist 7-OH-DPAT could be prevented by either selective D1-type or D2-type dopamine receptor antagonists. In three experiments, male Wistar rats (250-350 g) were given seven to nine injections (at 48-h intervals) of 7-OH-DPAT (1.0 mg/kg, SC) or vehicle in combination with the D2-type dopamine antagonist eticlopride (0.3 mg/kg, SC), the D1-type dopamine antagonist SCH 23390 (0.1 or 0.2 mg/kg, SC), or vehicle. After the injections, the rats were tested for locomotor activity in photocell arenas for 2 h. In the first two experiments, after seven injections, all rats were tested for activity following vehicle injections to test for possible conditioning effects. In each experiment, after the last pre-exposure session, all rats were given a challenge injection of 7-OH-DPAT (1.0 mg/kg, SC) and tested for activity. Major findings were as follows: a) 7-OH-DPAT treatments produced a progressively greater increase in locomotor activity with repeated treatment; b) concurrent treatment with eticlopride or SCH 23390 (0.1 and 0.2 mg/kg) blocked the acute locomotor-activating effects of 7-OH-DPAT across days; c) eticlopride, but not SCH 23390, completely blocked the development of behavioral sensitization to 7-OH-DPAT. Although the low dose of SCH 23390 (0.1 mg/kg) produced a partial attenuation of sensitization, the higher dose (0.2 mg/kg) of SCH 23390 appeared to augment, rather than block, sensitization to 7-OH-DPAT; d) rats previously treated with SCH 23390 (0.2 mg/kg, but not 0.1 mg/kg) without 7-OH-DPAT displayed a hyperactive response to the 7-OH-DPAT challenge injection; and e) after vehicle injections, rats previously given 7-OH-DPAT, SCH 23390, or eticlopride either alone or in combination were more active than vehicle control rats. These findings suggest that the neurochemical mechanisms mediating the development of behavioral sensitization to 7-OH-DPAT may differ from those of other dopamine D2-type agonists such as quinpirole or bromocriptine. Moreover, these results demonstrate that hyperactivity responses following vehicle injections in drug-pretreated animals do not necessarily reflect conditioning mechanisms. SN - 0033-3158 UR - https://www.unboundmedicine.com/medline/citation/9888612/Effects_of_selective_dopamine_D1__and_D2_type_receptor_antagonists_on_the_development_of_behavioral_sensitization_to_7_OH_DPAT_ L2 - https://dx.doi.org/10.1007/s002130050780 DB - PRIME DP - Unbound Medicine ER -