HIGH-INTENSITY SOCIAL-CONFLICT IN THE SWISS ALBINO MOUSE INDUCES ANALGESIA MODULATED BY 5-HT1A RECEPTORS

Social conflict between mice produces analgesia in the attacked mouse. Both the magnitude and type (opioid or nonopioid) of this analgesia h ave been related to attack intensity and strain of mouse. In the prese nt study low intensity social conflict (7 bites) did not produce analg esia, whereas high intensity - 30 and 60 bites interactions produced, respectively, short-lasting (5 min) and very short-lasting (1 min) ana lgesia in Swiss albino mice, when compared with nonaggressive interact ion (0 bite). The 30 bites aggressive interaction induced analgesia (A IIA) was not affected by IP injection of either naloxone (5.0 and 7.5 mg/kg) or diazepam (0.5, 1.0, 2.0 and 4.0 mg/kg). However, this attack -induced analgesia was reduced after IP administration of the 5-HT1A a gonists, gepirone (0.3 and 3.0 mg/kg) and BAY R 1531 (0.01 mg/kg). The se results indicate that the analgesia induced by 30 bites social conf lict in Swiss albino mice does not involve opioid and GABA-benzodiazep ine (GABA-BZD) mechanisms. In addition, they suggest that high-intensi ty social conflict activates serotonergic pain modulatory systems that act through 5-HT1A receptors. Copyright (C) 1997 Elsevier Science Inc .