Sympathetic neuronal destruction in macaque monkeys by guanethidine and guanacline

To determine whether the peripheral sympathetic neurons of subhuman primates are destroyed by guanacline treatment, we treated Macaca fasicularis with 2 or 20 mg/kg of guanethidine, guanacline, or the saturated analog of guanacline (SAG) 5 times per week for 4 or 12 weeks. All monkeys given 20 mg/kg of guanethidine, guanacline, or SAG showed a marked loss of neurons in the ganglia of the peripheral sympathetic nervous system. Treatment of macaques with 2 mg/kg of the guanidinium compounds resulted in patches of small-cell infiltrate, slight neuronal loss, and degenerative alterations in the sympathetic ganglia. Neuronal alterations in sympathetic ganglia of all treated monkeys were accompanied by a prominent heterogeneous infiltrate of mononuclear cells arranged primarily in a perivascular distribution and extending into the ganglionic neuropil. Peripheral sensory ganglia were unaffected. These histological findings are similar to those described in the guanethidine-induced immune-mediated sympathectomy, which has been extensively studied in the rat.