Antinociception induced by acute oral administration of sweet substance in young and adult rodents: The role of endogenous opioid peptides chemical mediators and mu(1)-opioid receptors

Author(s)

de Freitas, Renato Leonardo ^{[1, 2]} ; Lopes Kuebler, Joao Marcus ^[1] ; Elias-Filho, Daoud Hibraim ^{[1, 2]} ; Coimbra, Norberto Cysne ^{[1, 2]}

Affiliation

^[1] Univ Sao Paulo, Fac Med Ribeirao Preto, Dept Farmacol, Lab Neuroanat & Neuropsicobiol, BR-14049900 Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Inst Neurociencias & Comportamento, BR-14049900 Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: Pharmacology Biochemistry and Behavior; v. 101, n. 2, p. 265-270, APR 2012.
• Web of Science Citations: 16

Abstract

The present work aimed to investigate the effects of acute sucrose treatment on the perception of painful stimuli. Specifically, we sought to determine the involvement of the endogenous opioid peptide-mediated system as well as the role of the mu(1)-opioid receptor in antinociception organisation induced by acute sucrose intake. Nociception was assessed with the tail-flick test in rats (75, 150 and 250 g) of different ages acutely pre-treated with 500 mu L. of a sucrose solution (25, 50, 150 and 250 g/L) or tap water. Young and Adult rats (250 g) showed antinociception after treatment with 50 g/L (during 5 min) and 150 g/L and 250 g/L (during 20 min) sucrose solutions. Surprisingly, this antinociception was more consistent in mature adult rodents than in pups. To evaluate the role of opioid systems, mature adult rodents were pre-treated with different doses (0.25, 1 or 4mg/kg) of the non-selective opioid receptor antagonist naloxone, the selective pi-opioid receptor antagonist naloxonazine or vehicle followed by 250 g/L sucrose solution treatment. Sucrose-induced antinociception was reduced by pre-treatment with both naloxone and naloxonazine. The present findings suggest that sweet substance-induced hypo-analgesia is augmented by increasing sucrose concentrations in young and adult rodents. Acute oral sucrose treatment inhibits pain in laboratory animal by mediating endogenous opioid peptide and mu(1)-opioid receptor actions. (C) 2011 Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 09/17258-5 - Study of the involvement of nitrergic system and of glutamatergic and cannabinoid-mediated neurotransmission from the medial prefrontal cortex in the analgesia induced by elaborated escape reactions evoked by GABAergic blockade in the medial hypothalamus
• Grantee: Renato Leonardo de Freitas
• Support Opportunities: Scholarships in Brazil - Post-Doctoral