Expt 11 Effect of drugs on locomotor activity using actophotometer

For educational purpose only

1. AIM: Effect of drugs on locomotor activity using actophotometer . Presented by: Prof. Mirza Anwar Baig Dept of Pharmcaology AIKTC, School of Pharmacy, New Panvel

2. Requirements: Animal – mice (same sex), 25-30 gm or rat (100-200 g) Drug: - Normal saline Chlorpromazine HCl - dose 3 mg/kg Caffein – dose 3mg/kg. Instruments: - Actophotometer , disposable syringe and needles.

3. PRINCIPLE: Most of the drugs acting on the CNS influences the locomotor activity on the human and animals. CNS depressant drugs like barbiturates and alcohol reduce motor activity , CNS stimulants like caffeine and amphetamine increase the activity. In other words locomotor activity is the index of wakefulness (alertness of mental activity). Chlorpromazine was introduced in 1952 as an antipsychotic drug . Tranquilizer ( neuroleptic ) i.e a drug that reduces mental tension and produces calmness without inducing sleep or depressing mental facility was used.

4. Principle: Actophotometer https://www.youtube.com/watch?v=3rJxYmbuvcY The spontaneous motor activity is measured by means of actophotometer . Movement of the animals in the actophotometer interrupt the light coming from the photocell. Whenever there is interruption of the light , it is recorded in terms of count by digital counter.

5. PROCEDURE: Weigh animals and labeled with picric acid solution. Fast all animals for at least 12Hrs before the administration of the drug but have free access to the water. On the day of the test divide the animals into groups of at least 6 rats in each group. Each animal acts as its own control in a group of 6 animals. Record their movement in the actophotometer for 10 mins at an interval of 30min. Note the basal activity score of all the animals

6. Procedure Cont… At the end of counting, remove each group and inject the test drug as per given dose. After pre-treatment (30 min for chlorpromazine and 10 min for barbiturates) record the movement in the actophotometer for 10 min at an interval of 30 min. Calculate the percentage decrease / increase in the locomotor activity.

7. Observation: Chlorpromazine: 3 mg/kg

8. Observation cont.. Caffeine: 3 mg/kg

9. Result (Graph):

10. Results: Reduction in locomotor activity score indicate the CNS depressant property of the drug. Increase in locomotro activity score indicate the CNS stimulant property of the drug. The chlorpromazine and caffeine were noted to produce CNS depressant and CNS stimulant effect respectively.

11. Application in research:

12. References: Ghosh MN. Fundamentals of Experimental Pharmacology. Hilton & Company, Kolkata. Kulkarni SK. Handbook of experimental pharmacology. VallabhPrakashan

13. Thank You