Immobility Responses Affected by Potassium in Old Rats

Four immobility responses (IR): elicited by clamping, bandaging, grasping and inversion, and their modification by potassium and spironolactone was studied in old Wistar rats (body weight, 500 g). When undrugged, only clamping and grasping, but not bandaging and inversion induced an IR in rats. Potassium and spironolactone significantly enhanced the duration of IR induced by clamping but not by grasping. They also induced an immobility response by bandaging, but not by inversion. The data suggest that IR induced by clamping and bandaging are somehow related to changes in the potassium serum levels. Consequently, such a relationship may be a suitable model to study some forms of paralysis in human beings which are related to changes in the potassium serum levels.