Anticonvulsive Effects of Sodium Phenobarbital

Experimental purposeExperimental purpose

To master the anticonvulsive effects of sodium phenobarbital and the elementary process of chi square test.

To be familiar with the experimental condition of screening Anticonvulsants.

Sedative and hypnotics are among the most widely prescribed drugs worldwide.

Major therapeutic use is to cause sedation or encourage sleep. Anxiety states and sleep disorder are common.

Action and useAction and use

sedative and hypnotics apt to induce sedative and hypnotics apt to induce tolerance and dependence tolerance and dependence

induce P-450 systeminduce P-450 system adverse effects are commonadverse effects are commonanticonvulsive effects anticonvulsive effects generalized tonic-clonic seizuresgeneralized tonic-clonic seizures

anesthesia and preanesthetic anesthesia and preanesthetic medication medication

enhance CNS depressionenhance CNS depression graded dose-dependent depression of graded dose-dependent depression of

CNS is a characteristic of sedative-CNS is a characteristic of sedative-hypnotics. hypnotics.

at still higher doses---coma and deathat still higher doses---coma and death

MechanismMechanism

It can activate GABAA receptor,

potentiate GABA action on chloride

entry into the neuron.

The GABAA receptor chloride ion channel complex has a structure assembled from five subunits.

Barbiturates Benzodiazepines

a increase the open time of Cl- channel

b increase the open frequency of Cl- channel

Adverse effectAdverse effect

drug hangover: tiredness after awakes tolerance: induce P-450 system addiction: abrupt withdrawal may cause

tremor, anxiety, weakness, restlessness, nausea and vomiting

respiratory depression allergy

PoisoningPoisoning: overdoses can cause death,

depression of respiration and central

cardiovascular depression.

Treatment: artificial respiration;

purging the stomach of its contents;

alkalinization of blood and urine; hemodialysis

Experimental animals

Mice (of either gender), 18~22g

                                                    

         

Experimental apparatusExperimental apparatus

Mouse cage

injector

Experimental drugsExperimental drugs

50mg% Dimefline ih0.4% Sodium Phenobarbital ip0.9% Sodium Chloride (Normal

Saline) ip

Experimental indicationExperimental indication

Tetanic straighten in hind limbs is positive.

Experimental procedureExperimental procedure

Take 48 mice, weigh them.All mice are assigned randomly to

experiment group and control group according to the principle that equal weight between groups.

Students are divided into twelve

groups, every group takes twe mice from experiment group and control group respectively. Mark each mouse, record the marker in the table.

Mice in experiment group are

administered Phenobarbital intraperitoneal at the dose of 0.5ml/20g. Similarity, mice at the dose 0.5mg/20g. Similarity, mice in control group are administered 0.9% Sodium Chloride intraperitoneal at the dose of 0.5ml/20g.

After 30 minutes, each mouse is administered 50mg% Dimefline subcutaneously in the dose of 0.5ml/20g.

After administering Dimefline, we observe the responds of mice for 30 minutes. If there is convulsive respond, we need to record it.

In the end, all students summary the results. Record the positive and negative number in experiment group and control group in the table.

Analyze and handle the resultsAnalyze and handle the results

We analyze the results with chi square test to see if there is statistical difference in the percentage of convulsion between experiment group and control group.

1. Calculate χ2 value

(1) Calculate χ(1) Calculate χ22 value with basic value with basic formula:formula:

Table 1. Descriptive chart of results A T A-T (A-T)2/T

Experiment group Positive number

negtive number

Control groupTotal  Positive number

negtive number

total

A: observed value T: theory value

(2) Calculate χ(2) Calculate χ22 value with value with quadruple tabular form:quadruple tabular form:

Table 2. Descriptive chart of results

Experiment group Control group ∑

positive number a b

negative number c d

∑

χ2= (ad-bc)2×n ／ (a+b) (a+c) (c+d) (b+d)

2. Compare the observed value with theory value to assess if there is statistical difference.

QuestionQuestion What are the methods of making convulsion

model? How to observe drug’s anticonvulsive effect?

Why anticonvulsive drug be administered before administering make convulsion drugs in our experiment?

Which data does the experiment data belong to? Which method we choose to analyze? How to do it?