Effect of repeated stress on novelty-induced antinociception in rats
Braz. j. med. biol. res
;
34(2): 241-244, Feb. 2001.
Article
Dans Anglais
| LILACS
| ID: lil-281602
RESUMO
There is extensive evidence that acute stress induces an analgesic response in rats. On the other hand, repeatedly stressed animals may present the opposite effect, i.e., hyperalgesia. Furthermore, exposure to novelty is known to induce antinociception. The effects of repeated restraint stress on nociception after exposure to novelty, as measured by the tail-flick latency (TFL), were studied in adult male rats. The animals were stressed by restraint 1 h daily, 5 days a week for 40 days. The control group was not submitted to restraint. Nociception was assessed with a tail-flick apparatus. After being familiarized with the TFL apparatus, each group was subdivided into two other groups, i.e., with or without novelty. Animals were subjected to the TFL measurement twice. For the animals exposed to novelty, the first TFL measurement was made immediately before, and the second 2 min after a 2-min exposure to a new environment. While the control group presented an increased TFL after exposure to a novel environment, chronically stressed animals did not show this effect. These results suggest that repeated restraint stress induces an alteration in the nociceptive response, perhaps as a result of an alteration in endogenous opioids in these animals
Texte intégral:
Disponible
Indice:
LILAS (Amériques)
Sujet Principal:
Stress psychologique
/
Comportement d'exploration
/
Analgésie
Type d'étude:
Étude observationnelle
Limites du sujet:
Animaux
langue:
Anglais
Texte intégral:
Braz. j. med. biol. res
Thème du journal:
Biologie
/
Médicament
Année:
2001
Type:
Article
Pays d'affiliation:
Brésil
Institution/Pays d'affiliation:
Universidade Federal do Rio Grande do Sul/BR
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