Producción CyT
Medicina - Aortic large-conductance calcium activated potassium channel and potassium channel with inwardly rectification are differently expressed in normotensive and hypertensive rats.
Congreso
Autoría:
Sosa Agustina ; Soria Damián ; Ramírez Hernán ; Tomat Analía ; ELESGARAY, ROSANA ; Arranz Cristina ; Caniffi CarolinaFecha:
2020Editorial y Lugar de Edición:
Fundación Revista Medicina (Buenos Aires)Resumen *
Potassium channels and C-type natriuretic peptide (CNP) play key roles in the regulation of vascular tone. Objective: to evaluate the aortic expression of BKCa and Kir channels in spontaneously hypertensive rats (SHR) and their role in the vasodilator effect of CNP.Experimental design: Male Wistar rats and SHR (14 weeks-old) were sacrificed and aorta was removed to determine: BKCa and Kir2.0 protein expression and vascular reactivity after CNP addition (1pmol/L - 1umol/L). Denuded aortic rings were pre-contracted with phenylephrine (1umol/L) in the presence or absence of tetraethylammonium (TEA, non-selectively potassium channel blocker, 1mmol/L), iberiotoxin (IbTx, BKCa blocker, 30nmol/L), or BaCl2 (Kir blocker, 30 umol/L). Statistical analysis: Results are expressed as mean±SEM, Student t-test or 2-way ANOVA, followed by Bonferroni posthoc test; n=4-6/group.Results: Protein content of BKCa and Kir2.0 was lower in SHR compared to Wistar rats (BKCa: Wistar=1.1±0.1 vs. SHR=0.7±0.1*; Kir2.0: Wistar=0.8±0.1 vs. 0.4±0.1*; *p<0.05). The maximal relaxant response of CNP (Emax: Wistar=54.8±7.3 vs. SHR=57.6±3.1) and the negative logarithm of the concentration that induces the 50% of Emax (pEC50: Wistar=6.7±0.1 vs. SHR=6.8±0.1) were similar in denuded rings between both groups. TEA abolished the vasodilator effect of CNP. IbTx and BaCl2 decreased Emax similarly (IbTx: Wistar=36.1±4.8**; SHR=33.5±3.2##; BaCl2: Wistar=35.5±3.6**; SHR=34.0±3.2##; **p<0.01 vs. Wistar; ##p<0.01 vs. SHR) in both groups. However, the pCE50 with IbTx was lower in Wistar (Wistar=6.3±0.1**; SHR=6.8±0.1; **p<0.01 vs. Wistar), while CNP pEC50 was more affected by opening of Kir channels in SHR (Wistar= 6.7±0.1; SHR=6.4±0.1##; ##p<0.01 vs. SHR).Conclusion: The endothelium-independent vasodilator effect of CNP appears to be more sensitive to Kir blockade and less sensitive to BKCa blockade in SHR, although the expression of both channels is decreased in this model of essential hypertension. Información suministrada por el agente en SIGEVAPalabras Clave
CNPPOTASSIUM CHANNELSSHRVASCULAR TONE