1. Introduction
An Actophotometer is a device used in pharmacology and physiology to measure locomotor activity in rodents. Locomotor activity reflects the animal’s alertness, CNS excitability, and motor behavior. It is widely used to screen CNS stimulants, CNS depressants, and to evaluate toxicity or neuropharmacological interventions.
The actophotometer works on the principle of photoelectric cells and interruption of light beams.
The instrument contains an arena fitted with multiple infrared light beams and photo-detectors.
As the rodent moves inside the chamber, it interrupts these beams.
Each interruption is counted as one activity count (horizontal or vertical movement).
Total activity in a defined time period indicates the locomotor performance of the animal.
3. Materials Required
Actophotometer (Digital or Analog type)
Experimental animals: Mice or Rats
Standard drug (e.g., Diazepam as CNS depressant / Amphetamine as CNS stimulant)
Test compound or extract
Weighing balance
Animal identification markers
Timer/stopwatch
Personal protective equipment (gloves, lab coat)
4. Experimental Design
Animals can be divided into groups: (3 groups find the Groups at the bottom)
Compare locomotor effect
Sample size: n = 6 per group recommended
Route of administration: Oral, i.p., or as required
Observation period: 5 min per animal (standard)
5. Calibration of Actophotometer
Before the experiment:
Switch ON the instrument.
Allow warming for 5–10 minutes.
Ensure zero reading on the display. If not zero, adjust baseline.
Test with a mock object to verify beam interruptions are counted.
Clean the chamber properly to remove odors or feces.
6. Procedure
6.1 Animal Acclimatization
Allow animals to acclimatize to the lab environment for 30 minutes before testing.
Handle them gently to avoid stress.
6.2 Basal Activity Recording
Place the first animal inside the actophotometer chamber.
Close the lid properly.
Set the timer for 5 minutes.
Start recording.
Note the basal activity count for each animal.
Remove the animal and proceed with the next one.
6.3 Drug Administration
Administer the standard drug and test compound to respective groups.
Wait for the onset of action (commonly 30–60 minutes depending on drug).
6.4 Post-Treatment Activity Recording
Place the treated animal again inside the actophotometer.
Record locomotor activity for 5 minutes.
Note the activity count.
Repeat for all animals.
7. Calculations
Percent Increase/Decrease in Activity (Find the Formula at the bottom)
Interpretation
CNS Stimulants → Increase locomotor activity
CNS Depressants → Decrease locomotor activity
Evaluate statistical significance using One-way ANOVA followed by post-hoc tests.
8. Precautions
Avoid noise or movement around the instrument during recording.
Clean the chamber between animals to avoid odor-based behavioral changes.
Handle animals gently to prevent stress-induced locomotion.
Ensure equal environmental conditions (lighting, temperature).
Calibrate the actophotometer before every experiment.
9. Applications
Screening of CNS stimulant and depressant drugs
Neurotoxicity evaluation
Behavioral pharmacology studies
Sedative/hypnotic activity assessment
General motor activity assessment
10. Expected Results
Diazepam (CNS depressant) → Significant reduction in activity counts
Amphetamine (CNS stimulant) → Increase in activity counts
Test drug → Change depending on pharmacological action
END OF THE DOCUMENT
Find More:
Hi. I’m Writer of Researchsop.com. ’ ’ Please share these SOPs to all concern pharma people for their development. I like to fullfill the need of curious people. These things inspire me to make things looks better.
0 comments:
Post a Comment