1. Effect of morphine on analgesia

2. Experimental purpose To observe the effect of morphine on analgesia.

3. Experimental method To observe the effect of morphine on analgesia by woolf hot plate and control the temperature at 55±1 ℃

4. Experimental principle To set a mouse on a certain temperature hot plate and record time from the beginning to appearance the phenomenon of licking the hind limb. To regard this time as its pain threshold. To determine the extent of boosting pain threshold of experiment group than control group.

5. Experimental animals Mice (female)

6. Experimental apparatus 1ml syrings woolf hot plate

7. Experimental drugs 0.04% morphine hydrochloride 0.9% sodium chloride (normal saline)

8. Experimental procedure Preparation : To heat thermostat- controlled waterbath by homeothermia equipment and keep water to touch hot plate. To contain the surface temperature of hot plate at 55±1 ℃.

9. Experimental procedure Division of labour : One person observes time, another observes the mouse and the third records the time.

10. Experimental procedure Divide into groups: To weigh the mouse and divide them into two groups according to the principle of interclass coincidence. Each group take two mice respectively from two groups and mark them.

11. Experimental procedure To carry out experiment: To measure the normal pain threshold of these mice by turns and regard the time as the nomal pain threshold before administration.

12. Experimental procedure When a people looks at the watch and gives an order, another sets a mouse to the hot plate immediately and cover it with a cage, observes it carefully. Usually, most of mice begin to enter an uneasy state, for example, rising forward limb, kicking hind limb and so on after 10-20s. But these phenomena are not certain. We only consider kicking hind limb as the index of algesia and record the time immediately, at the same time, unload the mouse.

13. Experimental procedure And then give these mice different drugs as follows: Experiment group: To administrate intraperitoneally 0.04% morphine hydrochloride at the dose of 0.5ml/20g. Control group: To administrate intraperitoneally 0.9% sodium chloride at the dose of 0.5ml/20g.

15. Experimental procedure To measure their pain threshold at 15min (30min, 45min) after injection. If the mouse does not lick hind limb beyond 60s, we record 60s. And unload the mouse immediately.

16. Experimental procedure Statistical analysis: (1) To list a table with the data of whole class and discriminate mean and standard deviation of the experiment group and control group.

17. Experimental procedure Statistical analysis: (2) To list a chart of the percentage of changing pain threshold after administration at 15min, 30min and 45min. x-axis represents time and y- axis represents the percentage of changing pain threshold. To draw a curve of experiment group and controls.

18. Experimental procedure To calculate the percentage of changing pain threshold with the results of whole class. the percentage of changing pain threshold = {[ the responding time after injection 15min (30min, 45mim) - the responding time before injection] / the responding time before injection} × 100%.

19. Experimental procedure Statistical analysis: (3) To use the data of the experiment group and the control group at 30 min to do the t-test.

20. Experimental procedure

21. Questions What is the announcements of determining pain threshold ? How do you make sure the results accurate? What basic process does the t-test have? Which two data can use t-test to compare? Why do you choose the 30min data of experiment group and controls to do the t-test?