Static magnetic field blood pressure buffering, baroreflex vs. vascular blood pressure control mechanism

Abstract

Purpose: We compared the effect of static magnetic field (SMF) and verapamil, a potent vascular calcium channel blocking agent, on sudden elevation in blood pressure in conjunction with arterial baroreflex sensitivity (BRS) and microcirculation.Materials and methods: Forty-four experiments were performed on conscious rabbits sedated using pentobarbital intravenous (i.v.) infusion (5 mg kg−1 h−1). Mean femoral artery blood pressure (MAP), heart rate, BRS and ear lobe skin microcirculatory blood flow, estimated using microphotoelectric plethysmography (MPPG), were simultaneously measured after a 40 min exposure of the sinocarotid baroreceptors to 350 mT SMF, generated by Nd2-Fe14-B magnets, or 30 min of verapamil i.v. administration (20 μg kg−1 min−1). BRS was assessed from heart rate and MAP responses to i.v. bolus of nitroprusside and phenylephrine.Results: The decrease in phenylephrine-induced abrupt elevation in MAP (ΔMAPAE) was significantly larger after verapamil than after SMF exposure. ΔMAPAE inversely correlated with verapamil-induced significant increase in ΔMPPG (r = 0.53, p < 0.000) and with SMF-induced significant increase in ΔBRS (r = 0.47, p < 0.016).Conclusions: Our results suggest that verapamil-potentiated vascular blood pressure buffering mechanism was more effective than SMF-potentiated baroreflex-mediated blood pressure buffering mechanism, and a potential benefit of both approaches in cardiovascular conditions with abrupt high elevation in blood pressure.