VPT 321: Veterinary Neuropharmacology (2+1) copy 1

PROCEDURE

Aim: To demonstrate the effect of local anaesthetic in guinea pigs.

Requisites

• Animals required: Guinea pig,
• Drugs required: Xylocaine 0.5% solution,
• Instruments required: Dental syringe and needle.
• A guinea pig of either sex can be taken and then shaved on its hind quarters one day prior to the experiment. On the day of experiment the animal is weighed and the sex noted. Then circular markings are made with visible ink on either side of the vertebral column on the shaved area to a diameter of 4cm.
• In one of the circles marked the animal is pricked with the tip of a needle or pin six times. The animal will respond to this stimulus either by making a jerky movement or make a scream all the six times. Then 0.1 ml of the 0.5% xylocaine is injected intradermally which will evinced by formation of a swelling. Then remove the needle but do not rub that area after injection. Wait for 10 minutes and then start pricking with tip of the pin six times and observe the response as before and note the response. Like this repeat every 10 minutes till all the effect is lost. When the animal does not respond to any of the pin pricks at one stage is said to be positive for local anesthetic effect. Tabulate the results and give your interpretation. Repeat the experiment in more areas of the same animal and calculate the mean response.