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Uploaded byMirzaAnwarBaig1
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Anticonvulsant effect of drugs by MES and PTZ method

1) The document describes experiments to test the anticonvulsant effects of drugs using maximum electroshock (MES) and pentylene tetrazole (PTZ) induced seizure models in rats and mice. 2) The experiments involve pretreating animals with test drugs or saline followed by inducing seizures using MES or PTZ and measuring the time taken for different phases of seizures. 3) Results show that pretreatment with diphenyl hydantoin sodium increases the time taken for tonic extension phase of MES induced seizures, indicating its anticonvulsant activity.

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AIM: Anticonvulsant effect of drugs by MES and PTZ method. Presented by: Prof. Mirza Anwar Baig Dept of Pharmcaology AIKTC, School of Pharmacy, New Panvel
REQUIREMENTS: – Animal – Albino rat (150-200gm) or mice (25-30gm). – Drug: - Normal saline (10ml/kg) Diphenyl hydantoin- Na (25mg/kg). – Instruments: - Electro-convulsometer, ear dip or corneal elect rat. – Pre-treatment time: - 60 mins.
PRINCIPLE:  The two commonly used models for convulsions are:- 1) Electrical induced. 2) Chemically induced seizures.  The ability of a drug to avoid specific stages is taken as its index of anticonvulsant activity.  Different types of epilepsy such as grandmal, petitmal and psychomotor type can be studied in the lab animals.  Maximum electroshock (MES) induced convulsions in animals represent grandmal epilepsy (tonic clonic seizure).  Chemo convulsion due to pentylene tetrazole produces tonic type of convulsion resemble petitmal convulsion (Absence) in human  MOA of phenytoin https://www.youtube.com/watch?v=sKs-sE28x14
PRINCIPLE: contd…  In MES convulsion the electroshock is applied through corneal electrodes or ear dips.  When corneal electrodes are applied and optic stimulation is given cortical excitation is produced and typical convulsions can be divided in 6 parts  Such as:-  Latent period  Clonus  Tonic Flexion  Tonic Extension  Clonic Convulsion  Depression / Stupor  The duration of each phase varies, the current tonic extension of hind limbs is regarded as the most intense component of a convulsion
PROCEDURES: • Mice of either sex weighting about 25-30 gm are used for the experiment. • One day before testing, the animals are given with an electrical shock of 150 mA for 0.2 seconds. It produces extension of hind limbs. Those animals which produce positive results are selected. • The selected animals are divided into 2 groups of 6 animals. • One group receives the test drug while the other receives saline or vehicle. Shock is given to all animals after 1 hours of drug administration and the time taken by each phase of convulsion is noted.
Results: Sr.No B.W Dose to be administered Time (sec) for various stages of convulsions. Recover/ death Flexion Extension Clonic Stupor 1 27 0.27 3 10 2 120 Recovery 2 31 0.31 4 11 3 119 Recovery 3 30 0.30 3 9 2 112 Death 4 37 0.37 2 11 3 124 Death 5 32 0.32 3 10 2 126 Death 6 34 0.34 4 12 4 121 Death Average 3.166 10.5 2.66 120.33 1. Control group Saline solution 10ml/kg
Sr.No B.W Dose to be adminstered Time (sec) for various stages of convulsions. Recover/ death Flexion Extension Clonic Stupor 1 27 0.625 3 3 2 111 Recovery 2 31 0.75 2 2 1 101 Recovery 3 30 0.8 2 1 2 98 Recovery 4 37 0.875 2 2 2 85 Recovery 5 32 0.825 3 3 1 91 Recovery 6 34 0.85 4 5 2 98 Recovery Average 2.66 2.66 1.66 97.33 2. Test Group Diphenyl hydantoin 25 mg/kg
Conclusion: • There is a decrease in time spent by animal in tonic extension phase of the convulsion which indicate anticonvulsant activity of phenytoin.
Application in research
References: • Ghosh MN. Fundamentals of Experimental Pharmacology. Hilton & Company, Kolkata. • Kulkarni SK. Handbook of experimental pharmacology. VallabhPrakashan
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