Biphasic dose-dependent modulation of cardiac parasympathetic activity by moxonidine, an imidazoline I1-receptor agonist.

摘要: Peripheral beta-adrenergic blockade and activation of central alpha 2 -adrenergic receptors have parasympathomimetic effects. The impact imidazoline I 1 -receptors on vagal activity is not yet clear, but there some evidence that agonists may inhibit the parasympathetic system. Parasympatholytic effects represent a risk for patient with reduced activity. To clarify effect stimulation activity, increasing doses moxonidine were applied subcutaneously to rats implanted telemetric transmitters. Heart rate blood pressure variability baroreflex sensitivity analyzed. Both, low (0.04, 0.12, 0.36 mg/kg) high (1.08 3.24 mg/kg), low-frequency power systolic variability, an index sympathetic vascular modulation. Despite this reduction, neither heart nor increased gain. A decline very frequency sign parasympatholysis, was observed moxonidine, which can explain absence change in rate. High profoundly augmented high-frequency sensitivity. These data suggest only sympatholytic also seems as well weak parasympatholytic effect. However, are strongly through -adrenoceptors. Recruitment -adrenoceptors results manifestation several side