Objective: To study the role of glucocorticoid i n the integration of sympathetic nervous system and cardiovascular activity. Methods: Neurons in the rostral ventrolateral medulla (RVLM) were extracelluarly recorded and identified as the presympathetic neurons of adult rats. The spontaneous discharge of the presympathetic neurons in the RVLM were observed by bolus intravenous injection of corticosterone (50, 100, 150 μg/kg） . Results: The firing rate of 12 presympathetic neurons was incr eased by intravenous application of corticosterone (P<0.05), and this effect showed a dose-dependent manner. The latency of excitatory effect was (104±2 5) s. Conclusion: Corticosterone can rapidly excite the presym pathetic neurons in the RVLM, this action might be involved in the integration o f sympathetic nervous system through the “rapid membrane effects”.