Evaluation of long-term chemical sympathectomy in adult rabbits.
Administration of 6-hydroxydopamine (6-OHDA) will produce long-term sympathectomy in newborn animals. This investigation was designed to determine whether or not a long-term sympathectomy can be achieved by repeated administration of 6-OHDA in adult rabbits. Chronic treatment with 6-OHDA lowered blood pressure on average of 9 mmHg; the carotid sinus reflex was depressed, in contrast to the pressure response to intravenously administered epinephrine, which was doubled. In a constant-flow hindlimb preparation, the response to norepinephrine (NE) in 6-OHDA-treated rats was 50% larger and lasted 3 times longer. NE uptake in vitro, which is proportional to the number of adrenergic nerve endings, was found to be diminished by 80-85% in aortas from 6-OHDA-treated animals, and the dose-response curve for NE was slightly shifted to the left. The number of ganglionic cells in the superior cervical ganglia in treated animals was decreased by 80%. In conclusion, results from 6-OHDA-treated adult animals were entirely consistent with the effects of long-term sympathectomy.
D000818:Animals; D001158:Arteries / Q000378:metabolism* / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects; D002346:Carotid Sinus / Q000502:physiology; D004837:Epinephrine / Q000378:metabolism; D006892:Hydroxydopamines / Q000494:pharmacology*; D009638:Norepinephrine / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D013564:Sympathetic Nervous System / Q000187:drug effects*
D006892:Hydroxydopamines; D009638:Norepinephrine; D004837:Epinephrine