Effects Of Skeletal Muscle Relaxant Using Rotarod Apparatus

Aim: To study the muscle relaxant property of diazepam in mice using rotarod apparatus.

Principle: One of the important pharmacological actions of anti-anxiety agents of benzodiazepam class of drugs is muscle relaxing property. The skeletal muscle relaxation together with a taming or
calming effect, these agents reduce anxiety and tension. The loss of muscle grip is an indication of
muscle relaxation. This effect can be easily studied in animals using inclined planes or rotating

The difference in the fall off time from the rotating rod between the control and diazepam
treated animal is taken as an index of muscle relaxation. The angle of the slope of the inclined
plane or the rate of rotation of the rod should be adjusted such that a normal mouse can stay on
the plane or on the rod for an appreciable period of time.


Animal : Mice (20-25gm)
Drugs: Diazepam of the drug and inject 1ml/100g of body weight of the mouse.
Equipment: Rotarod apparatus


  • Weigh the animals and number them.
  • Turn on the instrument select an appropriate speed (20-25rpm)
  • Place the animals one by one on the rotating rod. One can place more than one mouse. Note down the fall-off time when the mouse falls from the rotating rod. A normal mouse generally falls off within 3-5 min
  • Inject diazepam to all animals. After 30 min repeat the experiments as done in step 3 note the fall off time.
  • Compare the fall off time of animals before and after diazepam treatment.

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