Heterogeneity in the performance of outbred Sprague-Dawley rats in an elevated-plus maze test: a possible animal model for anxiety disorder.
A wide variation in the performance of inbred rats measured in the evaluated plus maze test suggests a possible genetic basis for anxiety response (AR). To gain further insight into the role of genetics in AR, we have characterized AR in male outbred S-D rats. Rats were placed in the black compartment (BC) facing the wall opposite the aperture and time needed for the animal to exit BC was noted. All rats underwent 3 successive trials 1-1.5 hrs apart. Naive rats showed a wide variation in their AR in trial 1(mean = 89 +/- 19 sec, range = 5-360 sec). Sixty-eight% of the rats exhibiting low AR exited BC in < 30 sec, whereas 16% stayed in for the entire 360 sec (high AR). On successive testing, there was a progressive increase in AR which reached to max on second trial (Trial 1: 89 +/- 19, Trial 2: 171 +/- 23, Trial 3: 210 +/- 22 sec, p < 0.0001). The time spent in BC on successive trials increased for most rats (33/44), decreased for some (2/44), showed min to no change (5/44) or erratic response (4/44) for others. In conclusion wide variation in the AR in outbred rats could be exploited to study genetic and neurochemical mechanisms of anxiety.
Department of Medicine, Louisiana State University Medical Center, New Orleans 70112, USA.
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D000818:Animals; D014151:Anti-Anxiety Agents / Q000627:therapeutic use; D001007:Anxiety / Q000188:drug therapy / Q000503:physiopathology*; D001522:Behavior, Animal; D003975:Diazepam / Q000627:therapeutic use; D004195:Disease Models, Animal; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
D014151:Anti-Anxiety Agents; D003975:Diazepam