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Role of hippocampal dopamine receptors in the antinociceptive responses induced by chemical stimulation of the lateral hypothalamus in animal model of acute pain.
- Source :
-
Brain research [Brain Res] 2020 May 01; Vol. 1734, pp. 146759. Date of Electronic Publication: 2020 Mar 02. - Publication Year :
- 2020
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Abstract
- Dopamine is the predominant catecholamine neurotransmitter in the mammalian brain which has been shown to play a critical role in antinociceptive process. Previous studies have shown that the role of CA1 region of the hippocampus in antinociception induced by stimulation of the lateral hypothalamus (LH) through the dopaminergic system in tonic pain. In this study, we tried to assess the involvement of intra-hippocampal D1- and D2-like dopamine receptors in the LH stimulation-induced antinociception during the tail-flick test as an animal model of acute pain. Ninety-five male Wistar rats were unilaterally implanted with two separate cannulae into the LH and CA1. Animals received intra-CA1 infusion of SCH-23390 (0.25, 1 and 4 µg/rat), as a D1-like dopamine receptor antagonist and sulpiride (0.125, 0.25, 1 and 4 µg/rat), as a D2-like dopamine receptor antagonist, 2 min before intra-LH administration of carbachol (250 nM/rat). The antinociceptive effects of SCH-23390 and sulpiride were measured by using a tail-flick analgesiometer and represented as the maximal possible effect (%MPE). Also, the locomotion tracking apparatus was used to measure the locomotor activity of animals. Results showed that intra-CA1 administration of SCH-23390 or sulpiride could prevent the intra-LH carbachol-induced antinociception. This effect was a little more dominant after blocking the D2-like dopamine receptor in the CA1. These findings revealed that D1- and D2-like dopamine receptors within the CA1 play an important role in antinociceptive responses induced by chemical stimulation of the LH. It could be suggested that dopamine receptors in the CA1 were triggered by LH orexinergic projections.<br /> (Copyright © 2020 Elsevier B.V. All rights reserved.)
- Subjects :
- Acute Pain chemically induced
Acute Pain drug therapy
Animals
Benzazepines administration & dosage
Dopamine D2 Receptor Antagonists administration & dosage
Dose-Response Relationship, Drug
Hypothalamic Area, Lateral drug effects
Male
Microinjections methods
Pain Measurement drug effects
Rats
Rats, Wistar
Receptors, Dopamine D1 antagonists & inhibitors
Stimulation, Chemical
Acute Pain metabolism
Disease Models, Animal
Hypothalamic Area, Lateral metabolism
Pain Measurement methods
Receptors, Dopamine D1 physiology
Receptors, Dopamine D2 physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1872-6240
- Volume :
- 1734
- Database :
- MEDLINE
- Journal :
- Brain research
- Publication Type :
- Academic Journal
- Accession number :
- 32135149
- Full Text :
- https://doi.org/10.1016/j.brainres.2020.146759