BACKGROUND
Algesia (sensitivity to pain) can be induced by various ways to the animals. Painful response can be noted with and without pain killers (analgesics).
Analgesic drugs inhibit the sensitivity to pain.1 Pain is induced by radiant heat applying on a selected spot generated by a beam of light.
REQUIREMENTS
Animals : Mice (20-25 g) or Rat (150-180 g)
Drugs : Morphine sulphate (5 mg/kg), inject i.p. 1 ml/100 g body weight,
Other drugs : Pentazocin (20 mg/kg, i.p.), Aspirin (100 mg/kg, p.o.)
Equipment : Tail flick analgesiometer, Mouse restraint
PROCEDURE
Weigh and mark the animals. Allow the animals to acclimatize. Hold the animal, gently cover with a glove to restrain.
Perform the experiment when the animal will be calm and without movement of tail. Ensure that the animals have no previous damage in the tail at the time of experiment.
Hold the test animal under heat source and press the start button. Heat will be applied not more than 3 cm from the tip. After application of heat, the animal will withdraw its tail with sudden flick.
Set a timer at the start of application of heat and note down the time of withdrawal of tail. The withdrawal of tail from the heat source is referred as tail flick latency.
Check the basal reaction time of animals and note down. When the reaction time reaches 10 sec will be considered maximum analgesia to avoid damage.
Start the experiment 30 min after drug treatment.2 Reaction time after 15, 30, 45 and 60 min of drug treatment will be noted.
Calculate the percentage of increase in reaction time or index of analgesia at above time interval.
Observation table for analgesic activity study
Sl. No. |
Body Weight |
Treatment |
Basal reaction time (sec) |
Reaction time after 30 min of drug treatment |
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CONCLUSION
Prolonged latency time ensures relief of pain. From this experiment it can be concluded that the tested drug has analgesic activity.
REFERENCES
- Tripathi KD. Essentials of Medical Pharmacology. 7th edn, Jaypee brothers medical publishers (Pvt) Ltd, New Delhi; 2013.
- Lalan BK, Hiray RS, Ghongane BB. Evaluation of Analgesic and Anti-Inflammatory Activity of Extract of Holoptelea Integrifolia and Argyreia Speciosa in Animal Models. J Clin Diagn Res. 2015;9(7):FF01–4.
Also read:
- Analgesic activity study of drugs by hot plate (Eddy’s hot plate) method
- Study of local anesthetics by Infiltration anaesthesia in guinea pig
- Study of local anesthetics by Surface anaesthesia on the cornea of rabbits
- Study of local anesthetics by Spinal anaesthesia in rats
- Study of local anesthetics by conduction anaesthesia in frogs
- Study of biotransformation and excretion of drug
- Study of diuretic activity of drugs
- Effect of drugs on gastrointestinal motility
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FAQs
After application of heat, the animal will withdraw its tail with sudden flick. Set a timer at the start of application of heat and note down the time of withdrawal of tail. The withdrawal of tail from the heat source is referred as tail flick latency.
Heat will be applied not more than 3 cm from the tip. After application of heat, the animal will withdraw its tail with sudden flick. Set a timer at the start of application of heat and note down the time of withdrawal of tail. The withdrawal of tail from the heat source is referred as tail flick latency. Check the basal reaction time of animals and note down. When the reaction time reaches 10 sec will be considered maximum analgesia to avoid damage.
Tail flick analgesiometer is used for tail flick method and hot plate (Eddy’s hot plate) method is used for analgesic activity study.