A D2-like receptor family agonist produces analgesia in mechanonociception but not in thermonociception at the spinal cord level in rats
| Autor: | Francisco Mercado, Francisco Pellicer, Ulises Coffeen, Karina Simón-Arceo, Bernardo Contreras, Ruth Fuentes-García, Angélica Almanza |
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| Rok vydání: | 2015 |
| Předmět: |
Male
Agonist Hot Temperature Quinpirole medicine.drug_class Clinical Biochemistry Pain Pharmacology Toxicology Biochemistry Behavioral Neuroscience chemistry.chemical_compound Dopamine Physical Stimulation medicine Animals Injections Spinal Biological Psychiatry Receptors Dopamine D2 business.industry Dopaminergic Rats DAMGO Nociception Spinal Cord chemistry D2-like receptor Dopamine receptor Dopamine Agonists Analgesia business medicine.drug |
| Zdroj: | Pharmacology Biochemistry and Behavior. 137:119-125 |
| ISSN: | 0091-3057 |
| DOI: | 10.1016/j.pbb.2015.08.013 |
| Popis: | The administration of dopaminergic drugs produces analgesia in individuals experiencing different types of pain. Analgesia induced by these drugs at the spinal cord level is mediated by D2-like agonists, which specifically inhibit the detection of nociceptive stimuli by sensory afferents. The extent of the analgesia provided by spinal dopamine agonists remains controversial, and the cellular mechanism of this analgesic process is poorly understood. The objective of this study was to evaluate the analgesic effect of quinpirole, a D2-like agonist, based on two nociceptive tests and at various doses that were selected to specifically activate dopamine receptors. We found that intrathecal quinpirole administration produces analgesia of mechanical but not thermal nociception and that the analgesic effect of quinpirole is reversed by a mix of D2, D3, and D4 receptor-specific antagonists, suggesting that the activation of all D2-like receptors is involved in the analgesia produced by intrathecal quinpirole. The differential effect on thermal and mechanical nociception was also tested upon the activation of μ-opioid receptors. As reported previously, low doses of the μ-opioid receptor agonist DAMGO produced analgesia of only thermonociception. This evidence shows that a D2-like receptor agonist administered at the spinal cord level produces analgesia specific to mechanonociception but not thermonociception. |
| Databáze: | OpenAIRE |
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