Catecholamine stimulation and the response to behavioral challenge in Wistar rats.
Male Wistar rats were injected with CH-38083, an alpha 2-adrenoceptor blocker, after which they were challenged by a size-matched Wistar or Long-Evans opponent. In residents facing low-aggression opponents, the alpha 2-adrenoceptor blockade significantly reduced aggressiveness, whereas in those facing highly aggressive opponents the treatment significantly increased aggression scores compared to saline-treated controls, irrespective of the strain of the intruder. When the animals were treated with CH-38083, the frequency of biting attacks correlated significantly with the aggressiveness of the opponent in residents fighting with Wistar and Long-Evans rats. Similar correlations were not found in control (saline-injected) rats. The results suggest that the catecholaminergic activation caused by the alpha 2 receptor antagonist elicits a more efficient adaptation to the behavioral actions of the opponent. Plasma corticosterone levels were not influenced by the treatment, but this variable seemed to be correlated with the defensive behavior performed by the intruder.
Haller
J
J
Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest.
D058669:Adrenergic alpha-2 Receptor Antagonists; D000374:Aggression / Q000187:drug effects*; D000818:Animals; D001599:Berberine / Q000031:analogs & derivatives / Q000494:pharmacology; D002395:Catecholamines / Q000494:pharmacology*; D003345:Corticosterone / Q000097:blood; D005106:Exploratory Behavior / Q000187:drug effects; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012919:Social Behavior; D013045:Species Specificity; D013268:Stimulation, Chemical
D058669:Adrenergic alpha-2 Receptor Antagonists; D002395:Catecholamines; D001599:Berberine; C048886:7,8-(methylenedioxy)-14-hydroxyberbane; D003345:Corticosterone