Effect of ketamine on presympathetic neurons in rostral ventrolateral medulla of rats.
AIM
To study the effects of ketamine on central sympathetic and cardiovascular regulation.


METHODS
The experiment was performed on 25 urethane anaesthetized, artificially ventilated adult rats. A total of 32 presympathetic neurons in the rostral ventrolateral medulla (RVLM) were electrophysiologically identified, which had properties of both barosensitivity and projection to the spinal cord. Responses of these neurons to intravenously administrated ketamine (a non competitive N-methyl-D aspartate receptor antagonist) were observed.


RESULTS
Intravenous injection of ketamine (3, 6, 12 mg/kg body weight) increased the firing rate and blocked the barosensitivity of presympathetic neurons in the RVLM in a dose dependent manner.


CONCLUSION
Ketamine could affect the sympathetic outflow by blocking tonic baroreceptor inhibition of the presympathetic neurons in the RVLM.