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Papers of the Week

Papers: 19 Mar 2022 - 25 Mar 2022

Pharmacology/Drug Development

2022 Mar 14

Eur J Pharmacol

Analgesia and pain: Dual effect of dopamine on the peripheral nociceptive system is dependent on D-or D-like receptor activation.


Queiroz BFG, Fonseca FCS, Ferreira RCM, Romero TRL, Perez AC, Duarte IDG
Eur J Pharmacol. 2022 Mar 14:174872.
PMID: 35300994.


In this study, a pharmacological approach, together with the paw pressure test, was used to investigate the role of dopamine and its receptors in the peripheral processing of the nociceptive response in mice. Initially, the administration of dopamine (5, 20, and 80 ng/paw) in the hind paw of male Swiss mice (30-40 g) promoted antinociceptive effects in a dose-dependent manner. This was considered a peripheral effect, as it did not produce changes in the nociceptive threshold of the contralateral paw. The D, D, and D dopamine receptor antagonists remoxipride (4 μg/paw), U99194 (16 μg/paw), and L-745,870 (16 μg/paw), respectively, reversed the dopamine-mediated antinociception in mice with PGE-induced hyperalgesia. The D and D dopamine receptor antagonists SKF 83566 (2 μg/paw) and SCH 23390 (1.6 μg/paw), respectively, did not alter dopamine antinociception. In contrast, dopamine at higher doses (0.1, 1, and 10 μg/paw) caused hyperalgesia in the animals, and the D and D receptor antagonists reversed this pronociceptive effect (10 μg/paw), whereas the D receptor antagonist remoxipride did not. Our data suggest that dopamine has a dual effect that depends on the dose, as it causes peripheral antinociceptive effects at small doses via the activation of D-like receptors and nociceptive effects at higher doses via the activation of D-like receptors.