[Effect of moxonidine on the cardiac chronotropic regulation in hypertensive rats SHR-SP].

The administration of moxonidine for two weeks in a daily dose of 2 or 10 mg/kg (p.o.) reduced the cardiac sympathetic tone in stroke-prone spontaneously hypertensive rats (SHR-SP) by 24.3 +/- 7.3 and 32.2 +/- 10.2%, respectively. In addition, the treatment influenced the cardiac baroreflex by decreasing the bradycardic plateau and increasing both bradycardic and tachycardic range. The baroreflex gain increased in a dose-dependent manner by 41.6 +/- 12.1 and 103.0 +/- 3.9%, respectively. These data indicate that moxonidine can modulate the cardiac autonomic (tonic and reflex) chronotropic control.