Atrial natriuretic factor inhibits norepinephrine biosynthesis and turnover in the rat hypothalamus

VATTA MS; RODRIGUEZ FERMEPIN M; DURANTE G; BIANCIOTTI LG; FERNADEZ BE

REGULATORY PEPTIDES

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 1999 vol. 85 p. 101 - 107

0167-0115

We have previously reported that atrial natriuretic factor (ANF) increased neuronal norepinephrine (NE) uptake and reduced basal andevoked neuronal NE release. Changes in NE uptake and release are generally associated to modifications in the synthesis and/or turnoverof the amine. On this basis, the aim of the present work was to study ANF effects in the rat hypothalamus on the following processes:endogenous content, utilization and turn-over of NE; tyrosine hydroxylase (TH) activity; cAMP and cGMP accumulation andphosphatidylinositol hydrolysis. Results showed that centrally applied ANF (100 ng/ml /min) increased the endogenous content of NE(45%) and diminished NE utilization. Ten nM ANF reduced the turnover of NE (53%). In addition, ANF (10 nM) inhibited basal andevoked (with 25 mM KCl) TH activity (30 and 64%, respectively). Cyclic GMP levels were increased by 10 nM ANF (100%). However,neither cAMP accumulation nor phosphatidylinositol breakdown were affected in the presence of 10 nM ANF. The results further supportthe role of ANF in the regulation of NE metabolism in the rat hypothalamus. ANF is likely to act as a negative putative neuromodulatorinhibiting noradrenergic neurotransmission by signaling through the activation of guanylate cyclase. Thus, ANF may be involved in theregulation of several central as well as peripheral physiological processes such as cardiovascular function, electrolyte and fluidhomeostasis, endocrine and neuroendocrine synthesis and secretion, behavior, thirst, appetite and anxiety that are mediated by centralnoradrenergic activity. Ó 1999 Elsevier Science B.V. All rights reserved.