GABAA receptor,KATP channel and L-type Ca2+ channel is associated with facilitation effect of H2S on the baroreceptor reflex in spontaneous hypertensive rats

BackgroundWe aimed to investigate whether the facilitating effect of H₂S on the baroreceptor reflex is associated with the GABA_A receptor, K_ATP channel and L-type Ca²⁺ channel pathway.MethodsSpontaneously hypertensive rats (SHRs) and Wistar Kyoto (WKY) rats were used to investigate the facilitating effect of H₂S on the baroreceptor reflex by perfusing the isolated carotid sinus. The mechanism by which H₂S facilitated the baroreceptor reflex was determined by using Bay K8644 (an agonist of calcium channels), glibenclamide (Gli, a K_ATP channel blocker), and picrotoxin (PIC, a blocker of γ-aminobutyric acid [GABA]_A receptor).ResultsAs compared with WKY rats, SHRs showed impaired baroreceptor reflex sensitivity, as demonstrated by a right and upward shift of the functional curve for the intrasinus pressure–arterial blood pressure relation. H₂S perfusion (25, 50, or 100 μmol/L) dose-dependently ameliorated the impaired sensitivity of the baroreceptor reflex. Bay K8644 (500 nmol/L), Gli (20 μmol/L) and PIC (50 μmol/L) all prevented H₂S ameliorating the impaired baroreceptor reflex.ConclusionsH₂S facilitating the baroreceptor reflex might be associated with activating the GABA_A receptor, opening the K_ATP channel, and closing the L-type Ca²⁺ channel. These areas should provide new targets for preventing and treating hypertension.