Prevention of hyperthermia-induced convulsions in immature rat by MR-2266, a kappa antagonist.

Abstract

The opioid receptor subtypes involved in hyperthermia-induced convulsions were studied by testing different opioid receptor-selective antagonists in unrestrained 15-day-old rats. Saline-injected animals exposed to an ambient temperature of 40 degrees C showed a gradual increase in body temperature reaching a maximum of 40.4 +/- 0.2 degrees C at 60 min. At this time all rat pups had convulsions and died. Similar results were obtained when the animals were pretreated with beta-funaltrexamine or 1 mg/kg ICI-154129. However, the injection of 10 mg/kg ICI-154129 prevented hyperthermia-induced convulsions (only 20% of the rats showed generalized convulsions at 90 min). Rats treated with the kappa antagonist MR-2266 also showed an increase in rectal temperature. However, none of the animals had convulsions or died. These results suggest that the kappa-opioid receptors are involved in convulsions induced by hyperthermia.

• Authors: M L Laorden, E Carrillo, M M Puig
• Journal: Methods and findings in experimental and clinical pharmacology (Methods Find Exp Clin Pharmacol) Vol. 13 Issue 9 Pg. 605-8 (Nov 1991) ISSN: 0379-0355 [Print] Spain
• PMID: 1686291 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Benzomorphans
• Narcotic Antagonists
• Receptors, Opioid
• Receptors, Opioid, kappa
• MR 2266
• Dynorphins

Topics

• Animals
• Benzomorphans (pharmacology, therapeutic use)
• Dynorphins (antagonists & inhibitors, metabolism)
• Female
• Hot Temperature
• Male
• Narcotic Antagonists
• Rats
• Rats, Inbred Strains
• Receptors, Opioid (physiology)
• Receptors, Opioid, kappa
• Seizures, Febrile (metabolism, prevention & control)