Long-term modulation of tyrosine hydroxylase activity and expression by endothelin-1 and -3 in the rat anterior and posterior hypothalamus

摘要

The ET system (precursor peptides, endothelin-converting enzyme, and receptors) is widely distributed in different mammalian tissues, including the central nervous system (4, 30). In the hypothalamus, the ET system is highly expressed, suggesting that these peptides participate in the regulation of diverse biological functions controlled at this level (4, 30). The hypothalamus coordinates endocrine, neuroendocrine, and auto-nomic signals involved in the control of the cardiovascular activity, water, and sodium homeostasis, as well as hormone release (18, 21, 37, 55). Among the different areas and nuclei that form the hypothalamus, the anterior and posterior hypo-thalamic regions play a major role in the regulation of the cardiovascular activity (37, 55). The anterior hypothalamic region (AHR) is a sympathoinhibitory area, whereas the posterior region (PHR) behaves as a sympathoexcitatory area (37). Functional impairment of these areas has been associated with hypertension (37, 55). In addition, ETs through ETa receptors in the spinal cord also regulate cardiovascular and sympathetic activity (42).