[The regulation of area postrema in cardiovascular function in rabbit].

AIM

To determine the role of area postrema (AP) of rabbit in the regulation of cardiovascular function.

METHODS

The rabbits were anesthetized with intravenous injection of 10% urethane and 1% chloralose, and were artificially ventilated. The changes of mean arterial pressure (MAP) and heart rate (HR) were observed when AP was electrically stimulated with different frequency (10 Hz -80 Hz) and after chemical lesion of CVLM or RVLM, respectively.

RESULTS

Electrical stimulation of AP with low frequency (10 Hz, 20 Hz) decreased MAP and HR. Stimulation with high frequency(60 Hz, 80 Hz) increased MAP but decreased HR. The changes in MAP and HR were significantly lower (P < 0.01) after CVLM was destroyed when electrical stimulation of AP with 20 Hz, and both changes of MAP and HR were disappeared (P < 0.01) after RVLM was destroyed when electrical stimulation with 20 and 80 Hz.

CONCLUSION

Electrical stimulation of AP with low frequency decreases MAP and HR, stimulation with high frequency induces an increase in MAP and decreases in HR. The former is probably related to excitation of CVLM, the cardiovascular effects induced by different frequency of electrical stimulation are all resulted from the activation of RVLM.