Cardiovascular effects of injection of argipressin into lateral septal nuclei in rats.

AIM

To determine whether argipressin (Arg) plays a role in central neural control of cardiovascular function by acting on the lateral septal nuclei (LSN).

METHODS

Measuring mean arterial blood pressure (MAP) and heart rate (HR) responses followed microinjection of Arg into the LSN of rats anesthetized with urethane.

RESULTS

Arg (100, 200, and 400 ng) injected into the LSN produced a dose-dependent hypertension and tachycardia. Maximal changes of MAP were 0.9 +/- 0.6, 2.3 +/- 1.3, 4.0 +/- 1.4 kPa, respectively; maximal changes of HR were 12 +/- 27, 50 +/- 33, and 89 +/- 27 bpm, respectively. Pretreatment of the LSN with a vasopressin 1 type antagonist d (CH2)5Tyr(Me) Arg abolished the MAP and HR responses produced by injection of Arg. Peripheral alpha-adrenergic blockade with phentolamine blocked the hypertension responses to injection of Arg into the LSN.

CONCLUSION

Arg acts in the region of the LSN to exert a central action on the cardiovascular system that is mediates by stimulation of sympathetic outflow.