@AJs:
Nightshade is the basis for Atropine, which slows the gut and dries mucous membranes. Bella Donna is the most powerful, but all potatoes (except yams and sweets), tomatoes, peppers, eggplant, etc are in the nightshade family and contain minimal amounts of Atropine.
Another use of atropine is to speed up a bradycardic heart. However, in field emergencies, if atropine is given too quickly, it will paradoxically slow the heart. The minimal amounts of atropine in potatoes and eggplant should be safe for a dog. Many dog foods use potato as the main starch. The bulk of atropine contained in potatoes is in the green part of the skin, if left in the light.
OK well in all the receipes, for example Dr. Dodds, Liver diet, that white potatoes are the base of the diet.. it does say "remove skins" or at least it is implied. I have always removed potato skins before feeding them to the Basenjis… that say, I have feed peppers, tomatoes, eggplant for years to my kids with no problems. As they say, all in moderation