Anticonvulsant effect of drugs by MES and PTZ method
BP408P Pharmacology I Practical / S Y B Pharmacy Notes
Aim:
To study the anticonvulsant activity of phenytoin against maximal electro shock-induced convulsion rats.
Principle:
Different types of epilepsy i.e., grant mal, petit mal or psychomotor type, can be studied in laboratory animals. The maximal electroshock (MES) induced convulsions in animals represent grandmal epilepsy. Similarly chemo- convulsion due to pentylene-tetrazol which produce clonic type of convulsion in man. These are the two procedures used to study convulsion and to test anticonvulsant drugs in laboratory animals.
In MES- convulsion electroshock is applied through the corneal electrodes. Through optic stimulation, cortical excitation is produced. The MES convulsion is divided into five phases are
- Tonic flexion
- Tonic extensor
- Clonic convulsion
- Stupor
- Recovery / death
A substance is known to possess anticonvulsant properties if it reduces or abolishes the extensor phase of MES convulsions both in rats and mice. It is advised the students should have a complete background in the pharmacology of anti epileptics drugs before performing this experiment.
Requirement:
Animal : Rats (150-200 gm)
Drugs: phenytoin (dose 25 mg/kg); prepare a stock solution
Equipment : electro- convulsiometer, cornel electrode (150 mA current for 0.2 sec) Stop watch.
Procedure:
- Weigh and number the animals. Divide them into two groups each consisting of 4-5 rats. One group is used as a control and the other for drug treatment.
- Hold the animals properly, place corneal electrodes on the cornea and apply the prescribed current. Note the different stages of convulsion
- Repeat with other animals of the control group
- Inject phenytoin I.P to a group of 4-5 rats. Wait for 30 min and subject to animals to electroconvulsions
- Note the reduction in time or abolition of the tonic extensor phase of MES convulsions.
- Introduction to experimental pharmacology.
- Commonly used instruments in experimental pharmacology.
- Study of common laboratory animals.
- Maintenance of laboratory animals as per CPCSEA guidelines.
- Common laboratory techniques.
- Study of different routes of drugs administration in mice/rats.
- Study effect of hepatic microsomal enzyme inducers on phenobarbitone sleeping time in mice.
- Effect of drugs on ciliary motility of frog oesophagus
- Effect of drugs on rabbit eye.
- Effects of skeletal muscle relaxants using rota-rod apparatus.
- Effect of drugs on locomotor activity using actophotometer.
- Anticonvulsant effect of drugs by MES and PTZ method.
- Study of stereotype and anti-catatonic activity of drugs on rats/mice.
- Study of anxiolytic activity of drugs using rats/mice.
- Study of local anesthetics by different methods
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