Effect of doxapram on inhibition of medullary respiratory center excitability by sevoflurane in rats / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effect of doxapram on inhibition of medullary respiratory center excitability by sevoflurane in rats.Methods Neonatal Sprague-Dawley rats of both sexes,aged 1-4 days,were used in this study.Isolated medulla oblongata-spinal cord specimens were made according to the method described by Suzue and perfused with the artificial cerebrospinal fluid saturated with 95％O2-5％CO2.The specimens were randomly divided into 3 groups ( n =9 each):control group (group C),sevoflurane group (group S) and sevoflurane + doxapram group (group S + D).Respiratory rhythmical discharge activity of the hypoglossal nerve rootlets was recorded using suction electrode.After 10 min of equilibration,the specimens were perfused with the artificial cerebrospinal fluid,5％ sevoflurane and the mixture of 5％ sevoflurane and 5 μmol/L doxapram for 10 min in groups C,S,and S + D respectively.The respiratory cycle,inspiratory time and integral amplitude of inspiratory discharge were recorded.Results Compared with group C,the respiratory cycle was significantly prolonged,the inspiratory time was significantly shortened,and the integral amplitude of inspiratory discharge was significantly decreased in group S (P ＜ 0.05),and no significant change was found in the parameters mentioned above in group S + D (P ＞ 0.05).Compared with group S,the respiratory cycle was significantly shortened,the inspiratory time was significantly prolonged,the integral amplitude of inspiratory discharge was significantly increased in group S + D ( P ＜ 0.05).Conclusion Doxapram antagonizes sevoflurane-induced inhibition of excitability of medullary respiratory center in rats.