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Involvement of D1/D2 dopamine receptors within the nucleus accumbens and ventral tegmental area in the development of sensitization to antinociceptive effect of morphine.
Pharmacol Biochem Behav. 2014 Mar; 118:16-21.PB

Abstract

The nucleus accumbens (NAc) and the ventral tegmental area (VTA) are two major areas for the mesolimbic dopaminergic system which are strongly involved in the development of behavioral sensitization. In the present study, we investigated the role of D1/D2 dopaminergic receptors within the NAc or VTA in response to sensitization to morphine by the tail-flick test as a model of acute pain. Sensitization was induced by subcutaneous (SC) injection of morphine (5 mg/kg), once daily for three days followed by 5 days free of drug. After the sensitization period, antinociceptive responses induced by an ineffective dose of morphine (1 mg/kg; SC) were obtained by the tail-flick test, and represented as maximal possible effect (%MPE). In experimental groups, D1 and D2 receptor antagonists, SCH-23390 and sulpiride (0.25, 1 and 4 μg/rat), were separately microinjected into the NAc or VTA, 10 min before morphine administration during the sensitization period, respectively. Results showed that injection of morphine during the sensitization period (development of sensitization) increased %MPE of the ineffective dose of morphine from 2.43±1.4% in naive to 47.75±4.01% in sensitized animals (P<0.001). Unilateral microinjections of different doses of the D1/D2 receptor antagonists, SCH-23390 and sulpiride, into the NAc dose-dependently decreased %MPEs in morphine-sensitized animals. Nonetheless, %MPEs were only affected by intra-VTA administration of SCH-23390 in morphine-sensitized animals (P<0.05). Our findings suggest that both the D1/D2 dopamine receptors in the NAc and the D1 receptors in the VTA may be of more important in the development of sensitization to morphine in rats.

Authors+Show Affiliations

Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, P.O. Box 19615-1178, Tehran, Iran.Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, P.O. Box 19615-1178, Tehran, Iran.Physiology-Pharmacology Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, P.O. Box 19615-1178, Tehran, Iran. Electronic address: Haghparast@yahoo.com.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

24418216

Citation

Reisi, Zahra, et al. "Involvement of D1/D2 Dopamine Receptors Within the Nucleus Accumbens and Ventral Tegmental Area in the Development of Sensitization to Antinociceptive Effect of Morphine." Pharmacology, Biochemistry, and Behavior, vol. 118, 2014, pp. 16-21.
Reisi Z, Bani-Ardalan M, Zarepour L, et al. Involvement of D1/D2 dopamine receptors within the nucleus accumbens and ventral tegmental area in the development of sensitization to antinociceptive effect of morphine. Pharmacol Biochem Behav. 2014;118:16-21.
Reisi, Z., Bani-Ardalan, M., Zarepour, L., & Haghparast, A. (2014). Involvement of D1/D2 dopamine receptors within the nucleus accumbens and ventral tegmental area in the development of sensitization to antinociceptive effect of morphine. Pharmacology, Biochemistry, and Behavior, 118, 16-21. https://doi.org/10.1016/j.pbb.2013.12.023
Reisi Z, et al. Involvement of D1/D2 Dopamine Receptors Within the Nucleus Accumbens and Ventral Tegmental Area in the Development of Sensitization to Antinociceptive Effect of Morphine. Pharmacol Biochem Behav. 2014;118:16-21. PubMed PMID: 24418216.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Involvement of D1/D2 dopamine receptors within the nucleus accumbens and ventral tegmental area in the development of sensitization to antinociceptive effect of morphine. AU - Reisi,Zahra, AU - Bani-Ardalan,Mahtash, AU - Zarepour,Leila, AU - Haghparast,Abbas, Y1 - 2014/01/10/ PY - 2013/09/16/received PY - 2013/12/27/revised PY - 2013/12/31/accepted PY - 2014/1/15/entrez PY - 2014/1/15/pubmed PY - 2014/11/5/medline KW - D1 dopamine receptor KW - D2 dopamine receptor KW - Morphine sensitization KW - Nucleus accumbens KW - Rat KW - Ventral tegmental area SP - 16 EP - 21 JF - Pharmacology, biochemistry, and behavior JO - Pharmacol Biochem Behav VL - 118 N2 - The nucleus accumbens (NAc) and the ventral tegmental area (VTA) are two major areas for the mesolimbic dopaminergic system which are strongly involved in the development of behavioral sensitization. In the present study, we investigated the role of D1/D2 dopaminergic receptors within the NAc or VTA in response to sensitization to morphine by the tail-flick test as a model of acute pain. Sensitization was induced by subcutaneous (SC) injection of morphine (5 mg/kg), once daily for three days followed by 5 days free of drug. After the sensitization period, antinociceptive responses induced by an ineffective dose of morphine (1 mg/kg; SC) were obtained by the tail-flick test, and represented as maximal possible effect (%MPE). In experimental groups, D1 and D2 receptor antagonists, SCH-23390 and sulpiride (0.25, 1 and 4 μg/rat), were separately microinjected into the NAc or VTA, 10 min before morphine administration during the sensitization period, respectively. Results showed that injection of morphine during the sensitization period (development of sensitization) increased %MPE of the ineffective dose of morphine from 2.43±1.4% in naive to 47.75±4.01% in sensitized animals (P<0.001). Unilateral microinjections of different doses of the D1/D2 receptor antagonists, SCH-23390 and sulpiride, into the NAc dose-dependently decreased %MPEs in morphine-sensitized animals. Nonetheless, %MPEs were only affected by intra-VTA administration of SCH-23390 in morphine-sensitized animals (P<0.05). Our findings suggest that both the D1/D2 dopamine receptors in the NAc and the D1 receptors in the VTA may be of more important in the development of sensitization to morphine in rats. SN - 1873-5177 UR - https://www.unboundmedicine.com/medline/citation/24418216/Involvement_of_D1/D2_dopamine_receptors_within_the_nucleus_accumbens_and_ventral_tegmental_area_in_the_development_of_sensitization_to_antinociceptive_effect_of_morphine_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0091-3057(14)00002-1 DB - PRIME DP - Unbound Medicine ER -