Envolvimento de receptores opióides e serotoninérgicos nos processos antinociceptivos induzidos por substância doce / Involvement of opioid and serotonergic receptors in antinociceptives process induced by sweet substance

AUTOR(ES)

Elce Cristina Côrtes Rebouças

DATA DE PUBLICAÇÃO

2004

RESUMO

Rationale: Sweet substance-induced antinociception has been widely studied, and the investigation of the neurotransmitters involved in the antinociceptive process is an important way for understanding the involvement of neural system controlling this kind of antinociception. Objective: The aim of this study is to investigate the involvement of opioid and serotonergic system in the sweet substance-induces antinociception. Methods: the present work was made in animal model (Rattus norvegicus, Rodentia, Muridae); with the aim of investigating if the chronic intake of sweet substance, such as sucrose, is followed by antinociception. Their tail withdrawal latencies in the tail-flick test (probably a spinal reflex) were measured before and immediately after this treatment. As there was not statistic significant differences between baseline values of different groups, an analgesia index was calculated from the withdrawal latencies before and after treatment. The involvement of endogenous opioid and serotonin in the antinociceptive process was investigated with specific and non-specific pharmacological antagonism on opioid and serotonergic receptors. Results: The analgesic effect of sucrose intake depends on the concentration of sucrose solution and on the time during which the solution is consumed. Naltrexone and methysergide decreased the sweet substance-induced antinociception (post 14 days of sucrose intake). These effects were corroborated by peripheral administration of naloxonazina and ketanserin. Conclusions: The present results suggest the involvement of endogenous opioids and serotonin in the antinociceptive process presently studied. µ1-opioid and 5-HT2 serotonergic receptors may be involved in the central regulation of the sweet substance-produced antinociception.

ASSUNTO(S)

serotonin antinocicepção 5ht2 serotonergic receptor. ingestão de sacarose serotonina antinociception endogenous opioids. µ1-opioid receptor receptor serotoninérgico 5-ht2 sucrose intake tail-flick test opióides endógenos teste de retirada de cauda receptor opióide µ1

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