Role of soluble adenylate cyclase (sAC) in basal cardiac contractility of normotrophic and hypertrophic hearts

MARÍA SOFÍA ESPEJO; VERÓNICA DE GIUSTI; NOELIA ROSSETTI; ERNESTO ALEJANDRO AIELLO; ALEJANDRO MARTÍN IBAÑEZ

Rosario

Congreso; SAFIS ANNUAL MEETING ROSARIO 2019; 2019

Sociedad Argentina de Fisiología

In the heart, cyclic AMP (cAMP), stimulating the protein kinase A (PKA) is associated to the excitation-contraction coupling regulation. Historically, the only known source of cAMP were the transmembrane adenylyl cyclases (tmACs). However, recently a cytosolic adenylyl cyclase (sAC) was described, which represents an alternative source of localized cAMP. Besides sAC was described to be present in the heart, its pathophysiological function is unknown. In addition, it is known that the cardiac Na+/HCO3- cotransporter (NBC) promotes the cellular co-influx of HCO3- and Na+. Since sAC activity is regulated by HCO3-, our purpose was to investigate the potential functional relationship between NBC and sAC in the cardiomyocyte. Male Wistar rats were used as a normotrophic model, whereas spontaneously hypertensive rats (SHR) or mice with thoracic aortic constriction (TAC) were used as hypertrophic model. Rat and mouse ventricular myocytes were isolated and loaded with Fura-2 in order to measure Ca2+ transient (Ca2+i) by epifluorescence. Sarcomere or cell shortening were measured as index of contractility. * indicates p