Effects of acute administration of nicotine and lobeline on agonistic encounters in male mice

The effects of acute administration of two nicotinic ligands, (-)-nicotine and (-)-lobeline were examined on isolation-induced aggression in mice. Ind ividually housed male mice confronted anosmic "standard opponents" in a neu tral arena 10 min after drug administration. Encounters were videotaped and evaluated using an ethologically based analysis facilitating estimation of time allocated to 11 broad behavioral categories, Nicotine did not have si gnificant effects on threat or attack but significantly; diminished time al located to digging, The lowest dose of lobeline significantly diminished at tack and induced a slight increase of immobility without significantly dimi nishing other behaviors with motor components, The intermediate and highest dose of lobeline reduced time allocated to all behaviors with motor compon ents. It is concluded that these two nicotinic agonists produce different b ehavioral profiles during agonistic encounters in mice but that this test m ag. not facilitate assessing the impact of such drugs on irritability. (C) 2000 Wiley-Liss, Inc.