Effect of ghrelin on the expression and activity of tyrosine hydroxylase, an enzyme involved in hypertension

GERARDO CORRADI, FLAVIA M. CERNIELLO; NADIA A. LONGO CARBAJOSA; MARIELA M. GIRONACCI ; MARIO PERELLO

Mendoza

Congreso; XXIV Congreso Argentino de Hipertensión Arterial; 2017

SAHA

Ghrelin, a hormone produced mainly in stomach upon specific stimuli, is involved in several metabolic and cardiovascular processes. Emerging evidence shows that ghrelin exhib¬its protective effects on the development of atherosclerosis via multiple pathways, includ¬ing induction of vasodilation and decrease of angiotensin (AngII)-induced inflammatory factors secretion. In the brain the receptor for ghrelin has been shown to localize in the main cardiovascular control centers in neurons of the nucleus tractus solitarius, and central administration of ghrelin attenuates renal and adipose tissue sympathetic nervous activity. Furthermore, microinjection of ghrelin into the nucleus of the solitary tract, the region of the brain that is important for controlling the autonomic nervous system induced a decrease in the heart rate and mean arterial pressure. Tyrosine hydroxylase (TH), the enzyme that catalyses the first and rate-limiting step in catecholamines biosynthesis, is involved in the development and maintenance of hypertension. The aim of this study was to examine the effect of ghrelin on TH expression and activity. PC12 cells were incubated in the presence or absence of 100 nM ghrelin during different times and TH expression and phosphorylation (as an index of TH activity) were evaluated by Western-blot and immunofluorescence. Our results showed that ghrelin modulate TH expression in PC12 cells in a time-dependent manner. TH expression showed an increase of 30±5% above basal after 30 min incubation but a decrease of 25±5% below basal after 24 h incubation in the presence of ghrelin (P