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Role of Acid‐Sensing Ion Channels in hemodynamic effects following nitric oxide inhibition in the rat
Author(s) -
Nwora Cornelius,
Oyekan Adebayo
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.1018.16
Subject(s) - chemistry , acid sensing ion channel , amiloride , nitric oxide , epithelial sodium channel , hemodynamics , medicine , pharmacology , endocrinology , ion channel , sodium , biochemistry , receptor , organic chemistry
Acid‐sensing ion channels (ASICs), a member of degenerin/ENaC/ASIC family, plays ubiquitous roles in the cardiovascular (CV) system as they contribute to exercise pressor reflex and potentiate myogenic tone. As nitric oxide (NO) is a ubiquitous player in CV regulation, this study evaluated ASICs role and the mechanisms of their involvement regulating systemic and renal hemodynamic changes following NO blockade. In the anesthetized rat, amiloride (AM; 2.5 mg/kg) or benzamil (BENZ; 0.7 mg/kg), ENaC/ASIC inhibitor, increased basal mean blood pressure (MBP) by 25±5 and 55±7 mmHg, respectively, but reduced renal cortical blood flow (RCBF) by 111±7 or 99±6 PU, respectively, suggesting that ASICs helps in maintaining BP and renal perfusion. AM or BENZ enhanced L‐NAME‐induced increase in MBP by 44±6 or 55±7%, respectively, but blunted the decrease in RCBF. Verapamil (1 mg/kg), a voltage‐operated calcium channel (VOCC) blocker, reversed the effects of AM and BENZ on basal and L‐NAME‐induced increase in MBP suggesting the contribution of IC Ca 2+ to the effects of ASICs. KB‐R7943 5 mg/kg), a Na + /Ca 2+ exchange (NCX) inhibitor, also reversed AM or BENZ effects on basal MBP but enhanced the effects on RCBF suggesting an effect of ionic movement via NCX. We suggest that ASICs regulate systemic and renal hemodynamics and the pressor responses due to NO withdrawal by mechanisms involving ionic movement across VOC and NCX.