Reduction of pressor response to stress by centrally acting apelin in spontaneously hypertensive rats.

BACKGROUND

Numerous studies suggest that apelin plays a significant role in cardiovascular regulation and in the pathogenesis of hypertension. The purpose of the present study was to determine whether apelin-13 (AP-13) is involved in the regulation of cardiovascular responses to acute stress in spontaneous hypertension.

METHODS

The effects of intracerebroventricular (ICV) administration of AP-13 on changes in mean arterial blood pressure (MABP) and heart rate evoked by an alarming stress (air jet stress) were compared in awake normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). The rats were divided into four groups: Groups 1 (WKY) and 3 (SHR) received ICV infusion of 0.9% sodium chloride (vehicle), whereas Groups 2 (WKY) and 4 (SHR) were ICV infused with AP-13. All animals were exposed to the alarming stress.

RESULTS

During the ICV administration of the vehicle, the pressor response to stress was significantly greater in SHR than in WKY. The ICV infusion of AP-13 reduced the pressor response evoked by the application of the stressor in SHR but not in WKY. It also abolished the difference in stress-induced MABP increases between WKY and SHR.

CONCLUSIONS

The results show that centrally acting apelin may play an essential role in the regulation of blood pressure responses to an alarming stress in SHR rats.