Effects of 6-hydroxydopamine in hypertensive adult miniature swine

To validate a miniature swine model of sympathectomy, six swine that had chronic high blood pressures for unknown reasons and five DOCA hypertensive swine were treated with a single dose of the neurotoxin 6-hydroxydopamine (6-OHDA) (50 mg/kg i.v.). One week after 6-OHDA, conscious mean arterial pressure (MAP) had fallen by 47-49 mmHg and the pressor response to tyramine was attenuated in both groups. Norepinephrine content was significantly decreased in the kidneys (>85% and left ventricle (>94% in both 6-OHDA treated groups. These results indicate that 6-OHDA can be used to effectively sympathectomize adult swine. Chemical sympathectomy of swine with either unexplained high blood pressure or experimentally induced DOCA hypertension resulted in an equivalent fall in MAP in both of these populations. Further studies using 6-OHDA in miniature swine may help to elucidate the mechanisms involved in maintaining hypertension in this animal model.