Antagonistic Activity

Objective

- Being able to recognize and describe the convulsive reaction and tetanus which occur in mice after the injection of strychnine sulfate.

- Observing the different levels of reaction which happen after the administration of sedation.

- Being able to measure the eye pupil diameter of rabbits and regconize the effect of atropine and pilocarpine on rabbit eye as well as other side effects.

- Having the ability to explain the result and understand the antagonistic activity between strychnine sulfate and barbituric on mice, atropine and pilocarpine on rabbit eye.

1. PRINCIPLE

Two drugs are called antagonists to each other when one of them acts against and exhibits the properties the the other one. In this lesson, we will study:

- Antagonistic activity between strychnine sulfate and barbituric on mice.- Antagonistic activity between atropine and pilocarpine on rabbit eye.

2. APPARATUS

2.1. Test on mice

- 2 sets of syringe 1ml and needle 26.- Glass bocals.- 4 mice with approximately equal weights, same gender.- Strychnine sulfate 0,019% solution. - Barbital sodium 1,5% solution.- Cotton wool, ethanol.

2.2. Test on rabbit

- 2 eye-droppers.- Atropine sulfate 1% solution.- Pilocarpine 1% solution.- Ruler.- Scissors. - Case to hold the rabbits.

3. TECHNIQUE

3.1. Test on mice

- Weigh and mark each mouse. Inject with a dose of 0,1ml/10g. Place each mouse in a separated bocal for the observing process.

- Mouse A: Inject subcutaneously the strychnine sulfate solution with a dose of 1,9mg/kg.

Stimulate slightly the mouse by knocking lightly on the bocal. Observe, note the time when the convulsive reaction and tetanus happen, then describe them.

- Mouse B: Give the intraperitonial injection of barbital sodium solution with a dose of 150mg/kg (or pentobarbital sodium solution - 50mg/kg).

Observe, note the time when the reactions occur. (reel, sleep, loss of leg contraction reflex, loss of balance reflex, loss of pain sensation, loss of pain reflex).

- Mouse C: Prepare 1 syringe of strychnine sulfate solution 1,9mg/kg and another syringe of barbital sodium solution 150mg/kg. To prevent the action of strychnine sulfate, give the intraperitonial injection of barbital sodium solution. Right after that, inject subcutaneously the strychnine sulfate solution.

Observe, note and compare the reactions of mouse C with mouse A’s and mouse B’s.

3.2. Test on rabbit

- Place the rabbit securely in the case with a proper direction which receive a stable light source.

- Trim the rabbit’s eyelashes, measure the eye pupil diameter.

Right eye: Drip 4 drops of atropin solution 1%. Measure the eye pupil diameter once each 5 mins within 25 minutes.

Right and left eye: Drip 4 drops of pilocarpin solution 1% into both eyes. Measure the eye pupil diameter once each 5 mins within 30 minutes.

Compare the impact of atropin and pilocarpin on each eye and their impact together on the right eye.

REPORT

1. TEST ON MICE

Mouse A Mouse B Mouse CGenderWeight (g)DrugInjection volumeRoute of administration

Note the time when the reactions occur.

Mouse A Mouse B Mouse CConvulsion after being stimulated by noiseTetanusBreathing rateReelSleepLoss of leg contraction reflexLoss of balance reflexLoss of pain sensationLoss of pain reflex

Compare the convulsant activity of the drugs (about 3 factors: intensity, speed and time) on Mouse A versus C.

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Compare the anti-convulsant activity of the drugs (about 3 factors: intensity, speed and time) on Mouse B versus C.

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Explain the result.

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2. TEST ON RABBIT

Eye pupil diameter (mm)Normal

Atropin 1% Pilocarpin 1%5’ 10’ 15’ 20’ 25’ 5’ 10’ 15’ 20’ 25’ 30’

Right eyeLeft eye

Explain the result.

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