Abstract: AIM: To investigate the regulative effects of 7-NI on anesthetic depths in rabbits induced by propo-fol. METHODS: Twenty Japanese large auris rabbits of both sexes were randomly divided into 2 groups (n=10 in each): control group was given 2 milliliter peanut oil, ip and trial group was given 50 mg·kg^-17-NI, ip. After twenty minutes of administration, propofol were target-controlled infused by Graseby 3 500 injection pump that connected with jugular vein. The loss of chewing was in-dicated the light anesthesia. The blood concentration of propofol and the bispectml index (BIS), and heart rate variability index(HRVI) were determined as the light an-esthetic depth reached. In order to observe the changes of BIS and HRVI, the control group was given 50 mg·kg^-17-NI, ip in the light anesthetic depth. RESULTS: 50 mg·kg^-17-NI significantly decreased the target blood concentrations in the light anesthetic depth. Administra-tion of 50 mg·kg^-1 7-NI increased the anesthetic depth after the light anesthetic depth reached (P>0.05). CONCLUSION: 7-NI can increase the anesthetic action of propofol by selectively inhibition of the activity of cen-tral nNOS, indicated that central NO/cGMP signal trans-duction pathway play an important role in the general an-esthesia machanism of propofol. Propofol may influence NO/cGMP signal transduction pathway by selectively inhi-bition of the activity of central nNOS.

Key words: 7-nitro indazole, propofol, target-con-trolled infusion, heart rate variability index