Meeting Abstract

P1.42  Wednesday, Jan. 4  Influence of AVT on corticosterone and aggression in lizards DUNHAM, LA*; WILCZYNSKI, W; Georgia State University, Atlanta; Georgia State University, Atlanta

Arginine vasotocin (AVT) is a potent regulator of social behavior in a wide variety of species, but little is known about its role in reptilian behavior. In mammals, AVT release increases corticosterone (CORT) secretion, and changes in circulating CORT levels are associated with changes in aggression. We set out to determine if AVT and CORT interact to influence behavior in the green anole lizard (Anolis carolinensis). Male anoles were pretreated with vehicle (VEH) or a CORT synthesis inhibitor (metyrapone, MET) followed by treatment with VEH or AVT 30 minutes later. As expected, pretreatment with MET followed by VEH significantly reduced plasma CORT (t=3.04, p=0.005). Treatment with AVT significantly increased CORT (t=8.30, p<0.001) even when pretreated with MET (within AVT treatment, CORT levels did not differ significantly between MET and VEH pretreatment; t=1.16, p=0.138), indicating that AVT can influence CORT by stimulating its release rather than inducing new CORT synthesis. A 30 minute aggression test was given and the number of displays quantified. To examine temporal differences in behavior due to metabolism of treatments, we separated the 30 min behavior test into three 10-minute segments. There were no significant differences in behavior between groups during the first and second time segments. In the final trial segment, a two way ANOVA revealed that AVT significantly reduced aggressive response, regardless of the presence of a CORT synthesis inhibitor (F=5.57, p=0.024). Treatment with MET did not affect behavior in any trial segment. Moreover, we found no significant correlation between CORT and overall behavior (r=-0.137, p=0.433). The results suggest that AVT influences both aggression and CORT in reptiles, but that the behavior change may be independent of the effect on CORT.