Abstract: | The 5HT1A receptor agonist ipsapirone (10 mg/kg) suppressed shock-induced aggression in wild and domesticated rats but did not affect predatory aggression in either group of animals. Ipsapirone decreased neophobia and inhibited defensive reactions by wild rats towards man in the glove test. 3H]8-OH-DPAT binding, which labels 5HT1A receptors, was significantly increased in the hypothalamus of domesticated rats in comparison with wild counterparts, while 5HT1A density was unchanged in the frontal cortex in domesticated animals. In essence, the aggressive reactions contributing to the defensive behavior complex in wild rats appear to be regulated through 5HT1A receptors. © 1992 Wiley-Liss, Inc. |