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Location ： ⎝⎛七乐彩⎞⎠ > Technical Support> Determination of half effective amount of pentobarbital sodium (ED50)

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The hypnotic ED50 value of intraperitoneal injection of sodium pentobarbital (57-33-0) in mice was measured. Sodium pentobarbital is a barbiturate sedative hypnotic,

The hypnotic effect of intraperitoneal injection of mice with appropriate doses is usually judged by the disappearance of righting reflex. This indicator is only positive (sleep) and

Negative (not sleeping) two phenomena, which are qualitative reactions. The abscissa of the mass-response dose-response curve is the logarithmic dose, and the ordinate is the positive response

When the frequency is generated, it is generally a normal distribution curve. If the cumulative positive frequency is changed to the ordinate, a standard S-shaped curve can be obtained. The curve

The central part (50% of the response) is close to a straight line with the largest slope, and the corresponding dose is to make a certain effect in half of the individuals in the group.

The appropriate dose is usually called the half-effect amount. If the effect is a curative effect, then the half effective amount (ED50) is called; if the effect is a death, the half is lethal

Volume (LD50). These values are important parameters for evaluating the strength of drug action and drug safety. 021-51602548

The design conditions of Sun's improved Kaerber method are as follows: the number of experimental animals in each group is equal, the doses in each group are in a proportional series, and the response rate of each group of animals is large

Consistent with normal distribution. If Xm is the logarithm of the dose of the maximum response rate group, i is the logarithm of the dose ratio between groups, p is the response rate of each group, and Pm is the maximum

High response rate, Pn is the lowest response rate, n is the number of experimental groups, then:

ED50 = lg-1 [Xm－ i （∑ P－ 0.5） ＋ i / 4 （1－ Pm－ Pn）]

With 0% and 100% response rates,

ED50 = lg-1 [Xm－ i (∑ P－ 0.5)]

95% confidence limit of ED50 = lg-1 (lgED50 ± 1.96 · S)

Where S = i

**Experimental materials**

50 mice, 1% sodium pentobarbital solution, mouse cage, balance, 0.5ml or 0.25ml syringe.

**Third, the experimental steps**

1. Determine the dosing dose: pre-experiment with a small number of animals to obtain the minimum dose of 100% hypnotic response to sodium pentobarbital (ED100)

And the response rate was 0% of the maximum dose (ED0). Then within this dose range, it is divided into several dose groups (usually 4 to 8 groups) according to the proportional series.

The common ratio (r) of the dose in each group is r = n-1√ ED100 / ED0

After finding r, multiply r by starting from the first dose group (ED0) to get the dose of the next next group. If divided into 5 groups,

Do not specify ED0, r · ED0, r2 · ED0, r3 · ED0, r4 · ED0, r5 · ED0.

2. Dosing: Take 50 healthy mice weighing about 25g, check the random number table, and randomly divide them into 5 groups, 8 in each group (except for extreme small weight)

2 rats). 0.1ml / 10g was injected intraperitoneally according to the concentration of each group listed in Table 1.

3. Recording results: Take the disappearance of righting reflex as the index of falling asleep, observe the hypnotic effect of the drug, and record the number of sleeping rats within 15 minutes after intraperitoneal injection.

Fill in Table 1.

**4. Experimental results**

Table 1 Calculation table for pentobarbital sodium ED50

According to the data in Table 1 and the above formula, ED50 = 31.90

**Precautions**

1. To reduce errors, dispense medicine by 1 person

2. Keep the environment quiet

3. If positive animals appear in the first group, increase the low-dose group by the common ratio (d0 = d1 / r)

4. The animals in the last group are not all positive, increase one dose upward (dk + 1 = dkr)

Anesthesia methods for experimental animals, in addition to using sodium pentobarbital for injection anesthesia, can also use isoflurane gas anesthesia:

**Small animal gas anesthesia machine**

**Animal insulation system**

对手术中的动物和术后恢复的动物进行保温，并可进行动物体温测量。 **The animal body temperature maintaining instrument (electric heating type) keeps** warming the animals during and after the operation, and can also measure the body temperature of the animals.

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