Pharmacology experiment - analgesic activity of drugs by using Eddys hot plate

Object  To study the analgesic activity of drugs by using Eddys hot plate  

Reference - TripathiK.D, "essentials of medical pharmacology", Jaypee brothers medical publishers LTD., 2015.

Requirement- PC & Expharm software 

Theory

Analgesic drug increase pain threshold (ability to tolerate a painful stimulus). This effect can be evaluated in animal models of analgesia. To induce pain , following type of stimuli can be used:

Radiant heat projected on the tail, paw or shaved skin

• Cold stimulus applied through a cold plate

• Mechanical pressure on tail or paw applied using a clamp 

• Chemical stimulus (formalin)

The time taken by the animal to reveal pain sensation through vocalization or paw licking or effort to escape the painful stimulus (withdrawal of the body part on which pain is inflicted-paw or tail) is determined. The analgesics increase the time taken by the treated animal to reveal pain sensation.

Eddy's hot-plate is a device used to give heat stimulus to the paws of animal. A metal plate at the top of hot plate apparatus can be heated in the controlled manner and maintained at the required temperature for the duration of an experiment. Generally, in testing of the analgesic activity of drug in animal, 55* C temperature is used as a thermal stimulus.

Analgesic activity of drugs by using Eddys hot plate

Procedure

• Animals are divided into two groups (6 animals in each)

• Administer one group with the drug (Pentazocine 10mg/kg) to be tested and other with vehicle by intraperitoneal route.

• After 60 minutes put the mice on the Hot Plate maintained at 550 C.

• Record the response time at which the mouse licks its fore paws or jumps.

Result