Abstract

Six New Zealand white rabbits were given gas induction anaesthetics and maintained on glucochloralose (Merck) 60 mg/kg given intravenously. Intracolonic pressures were measured after a standard dose of prostigmine, 0·05 mg/kg, using fluid-filled, open-tipped, narrow-bore polythene tubes. Then the rabbits were put on a diet of white bread, butter, milk, and sugar supplemented by vitamins for four months. All six rabbits had put on weight but their general condition deteriorated; they had become constipated and the colon contracted. After stimulation with prostigmine 0·05 mg/kg scattered intertaenial wide-necked diverticula appeared which were thinner than the normal haustra and looked like a blackcurrant in colour, size, and shape. Repeat pressure measurements showed that the colonic motility index was increased up to 10 times from predietary levels with a highly significant mean increase from 5299 to 33151 (p < 0·0005).