Behavioural Brain Research 78 (1996) 175 182
Behavioral changes in Anolis carolinensis following injection
A. Wallace Deckel 1
University of Connecticut Health Center, MC 2103, 263 Farmington Avenue, Farmington, CT06030, USA
Received 31 March 1995; revised 31 August 1995; accepted 31 October 1995
Eight adult male lizards of the genus and species Anolis carolinensis were used in this experiment. In order to induce aggressive
responding, animals were caged separately and daily underwent pairing with another male, during which aggressive responses and
changes in skin color were measured. After obtaining a baseline measure of aggressive responding, animals were injected either
with fluoxetine or vehicle-controls in a cross-over design. Subjects were then exposed to five more days of (non drug) pairing with
the intruder male, after which they underwent a second trial with fluoxetine/vehicle. Finally, two post-drug paired-trials were
obtained. Fluoxetine injection significantly reduced the aggressive responding in the males while causing the postorbital eyespot
to significantly darken. Subjects also showed increased aggressivity and skin-color reactivity subsequent to the two drug trials,
although it is unclear if the fluoxetine, or non-specific factors of the injection paradigm, accounted for these changes. These results
suggest that serotonergic CNS systems tonically regulate aggression in Anolis carolinesis, similar to that seen in many other species.
They further suggest that eyespot-darkening and aggressive responding can be pharmacologically dissociated, implicating serotonin
in the regulation of this phenomenon.
Keywords: Anolis carolinensis; Aggression; Fluoxetine; Lizard; Behavior; Brain; Serotonin
A number of laboratories have reported on the use of
the lizard species Anolis carolinensis, in studies examining
aggression and aggressive behaviors [1-11]. Anolis c.
has a number of clearly iden