Aim:

  • To study drug (phenothiazines)- induced catatonia (extrapyramidal side effect in rats.
  • to study the anticatatonic (antiparkinsonian) effect of scopolamine.

Principle: Phenothiazine and butyrophenone type antipsychotic drugs are known to produce extrapyramidal side-effects in man these effects, such as akinesia, rigidity and tremors, are called Parkinson’s- like because in Parkinson’s disease the major clinical symptoms include difficulty to move and change posture (akinesia and rigidity) and tremors. These effects of antipsychotic drugs are due to excessive blockade of dopamine receptors in the extrapyramidal motor system.
Therefore, phenothiazines (chlorpromazine or perphenazine) are commonly used to produce Parkinson’s-like extrapyramidal symptoms in laboratory animals and to study anti-parkinsonism
drugs. The students are advised to know the pharmacology of anti-parkinsonism drugs before
performing this experiment.

Requirements
Animal: Rats (150-200 g)
Drugs: Perphenazine (dose: 5 mg/kg IP; prepare a stock solution containing 1 mg/ml of the drug and inject 0.5 ml/100g bodyweight of the animal). Scopolamine (dose: 2mg/kg, IP prepare a stock solution containing 0.4 mg/ml of the drug and inject 0.5 ml/100 g body weight of the animal)
Equipment: two wooden blocks, one being 3 cm high and the other 9 cm high

Procedure:

  1. Weigh and number the animal. Divide the animals into two groups, one for control (for
    study of perphenazine effect) and the other for studying the effects of scopolamine. Each
    group should consist of at least 5 animals.
  2. Inject perphenazine to control animals. observe severity of catatonic response (fig 5.14) as follows:
  1. Observe the severity of catatonia at 5,15,30,45,60,90 and 120 min after perphenazine .
  2. To the second group inject scopolamine and after 30 minute inject perphenazine to these
    animals already treated with scopolamine. Observe and score the severity of catatonic as in
    step 2.
  3. Compare the onset and severity of catatonic response in the both groups. Plot a graph, time
    along the x-axis. Note the difference in the onset and severity of catatonic response in both
    the groups.

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