Abstract
The time course of degeneration and recovery of adrenergic nerve terminals (ANT) produced by a single dose of 6-hydroxydopamine (6-OHDA) was studied. The norepinephrine content (NE) of the ventricles, submaxillary glands and vas deferens was assayed, and the ANT were observed by the histochemical fluorescence method. NE was reduced to less than 10% of normal in the ventricle and submaxillary glands, but was not affected in the vas deferens, 24 hours after 6-OHDA (16.5 mg/kg). The ANT of the atria, ventricles and submaxillary glands were markedly depleted, and degenerative changes with increased fluorescence were seen in the preterminals. After an i.p. dose of 16.5 mg/kg, the NE returned to normal by 8 weeks (submaxillary) or 12 weeks (ventricles). Reinnervation of nerves to the blood vessels occurred earlier than to the myocardium or gland cells. Decentralization of the superior cervical ganglion did not alter the NE-depleting action of 6-OHDA in the submaxillary gland. When hearts of rats pretreated with 6-OHDA were isolated and perfused with NE (1 or 20 µg/ml) for 10 minutes, no increase in the number of ANT was noted. It is concluded that a single i.p. dose of 6-OHDA can cause a marked reduction in the NE content of the rat heart and submaxillary gland and accomplish a functional impairment or destruction of the adrenergic nerve terminals.
Footnotes
- Received July 8, 1970.
- Accepted September 21, 1970.
- © 1971, by The Williams & Wilkins Company
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