I need help with finding a cartoon/movie about a mouse/rat?

The movie I think was in the late 80's it was about a mother mouse/rat that wore a necklace that had a oval charm that at one pont in the movie lit up and started to glow and a light shined outward and bright I even think she kinda got lifted up into the light.. She also wore and shaw (possibly red?). I beleive the story pertained to her and her serch for somthing(sorry I dont remember to much and i dont want to conflict memories on another mouse story like Fifel.) Any help would be great!