Adrenergic denervation of guinea pig trachea with 6-hydroxydopamine

We studied adrenergic nerve morphology and function in guinea pig trachea in relationship to dose and time after administration of 6-hydroxy dopamine (6-OHDA). At one day after maximally tolerated doses (400 mg/kg on two or five successive days) adrenergic nerve histofluorescence was abolished. Histofluorescence was again visible at eight days after treatment and was indistinguishable from controls at 30 days, a pattern also observed in heart and iris. In isolated tracheal segments from treated animals there was suppression of³H-norepinephrine uptake, supersensitivity to applied norepinephrine, and a decrease in the adrenergic component of electrical stimulation-induced relaxation. We conclude that 6-OHDA is effective in producing fairly complete, but transient, adrenergic denervation of guinea pig airways.