Title

24 Hour changes in catecholamine content of rat thyroid and submaxillary glands

Document Type

Journal Article

Publication Date

10-1-1988

Journal

Journal of Neural Transmission

Volume

71

Issue

3

DOI

10.1007/BF01245712

Keywords

24 h rhythm; dopamine; epinephrine; norepinephrine; submaxillary glands; Superior cervical ganglion; thyroid

Abstract

The occurrence of diurnal rhythmicity in tissue norepinephrine (NE), epinephrine (E) and dopamine (DA) levels of rat thyroid and submaxillary glands was assessed in animals killed at eight time intervals during a 24 hour period. In both tissues significant peak values of NE content were found at the third hour of dark onset (at 23:00 h). Additionally a minimum of NE content of thyroid gland was apparent in rats killed at the fifth hour of photophase (at 11:00 h). As in the case of NE, peak values of E content were found during the scotophase in both tissues examined. In contrast, DA levels exhibited no diurnal rhythmicity in the rat thyroid gland, and an early rise at the beginning of the photophase in the submaxillary glands. These results support an activation of the sympathetic nervous system innervating the thyroid and submaxillary glands at the beginning of the scotophase. Tissue DA levels do not resemble the activity of peripheral sympathetic nerves in the tissues examined. © 1988 Springer Verlag.

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