Substance for vasoconstriction which influences local anesthesiaClass A, 09 Grade, Guiynang Medial Hospital (贵阳550002)Huquan Mao Liying Meng Guya YangLluqian Tan Yuhui Yang Song Qucheng Li LingLuo Heyuyang Han Yan (Briefing) Purpose: By doing experiments we have observed and discussed whether vasoconstrictor or vasodilator had ever influenced the working time of local anesthesia . The Methods:------ The way we used is to randomly number and group the grown-up white mice—Kunming mice who were able to have normal pain reflex. .Right after we separately gave these white mice (marked with group number) caudal vein injections with corresponding concentrational saline water, epinephrine, norepinephrine,and phentolamine, we gave the buttocks subcutaneous injection with procaine, then we observed and recorded the time of the pain reflex which had vanished ,and noted the time they recovered.,. Therefore we compared the effects of all above the medicines for lengthening the anesthesia time of procaine or shortening the anesthesia procaine The result of the comparation between epinephrine, norepinephrine,and and phentolamine with saline water group about lengthening or shortening anesthesia time for procaine is different like this, to lengthen, to lengthen, and to shorten, and the effect of epinephrine was stronger than that of norepinephrine. Summing Up: epinephrine norepinephrine and other vasoconstrictor and vasodilator like phentolamine affect the anesthesia time of procaine. (Key words) epinephrine, norepinephrine, phentolamine, procaine.