Tetrodotoxin functional ablation of dorsal raphe before training impaired acquisition and retrieval of spatial reference memory in male rats

Here we report the role of pretraining dorsal raphe nucleus (DRN) functional inactivation on spatial learning in Morris water maze (MWM) task. Male rats were divided into four groups: control, sham operated, saline injected, and DRN inactivated. Saline injected group received saline and DRN inactivated group received tetrodotoxin; whereas sham operated group and control group received no injection. Our findings were: 1) Functional inactivation of DRN impairs acquisition of spatial reference memory; 2) Reversible inactivation of the DRN impairs retention of spatial reference memory; and, 3) DRN inactivation has no effect on visual acuity.