Regulation of tyrosine hydroxylase by ETA receptors in the olfactory bulb of DOCA-salt hypertensive rats

MARIA JULIA GUIL; VANINA P. MORALES; CELESTE V. SORIA; SANDRA I HOPE; LILIANA G. BIANCIOTTI; MARCELO S. VATTA

Congreso; Experimental Biology'12; 2012

We recently showed that olfactory bulb (OB) exposure to endothelins (ETs) differentially modulate tyrosine hydroxylase (TH) activity and expression in normotensive rats. In the present study we evaluated the regulation of TH by ETs in hypertension. BQ610 (selective ETA antagonist) (20uM/ul/min) was intracerebroventriculary applied to normotensive and DOCA-Salt hypertensive rats. Blood pressure and heart rate were monitored by 60 min and then animals sacrificed to obtain OB where TH activity (radioenzymatic method) and expression of total enzyme and phosphorylated forms (western blot) were assessed. Following BQ610 administration blood pressure and heart rate were reduced in hypertensive rats but no changes were observed in control animals (control, salt or DOCA only). Hypertensive rats exhibited an increase in TH activity as well as in total TH and its phosphorylated forms (pSer19, pSer31 and pSer40) that were diminished to control levels by BQ610 administration. These findings support an interaction between ETs and TH in the OB of DOCA-salt hypertensive rats likely related with the onset and/or development of hypertension in this animal model