TY - JOUR
T1 - Effects of endogenous cannabinoid anandamide on cardiac Na+/Ca2+ exchanger
AU - Kury, Lina T.Al
AU - Yang, Keun Hang Susan
AU - Thayyullathil, Faisal T.
AU - Rajesh, Mohanraj
AU - Ali, Ramez M.
AU - Shuba, Yaroslav M.
AU - Howarth, Frank Christopher
AU - Galadari, Sehamuddin
AU - Oz, Murat
N1 - Funding Information:
This study was in part supported by the NIDA/NIH, USA and the United Arab Emirates University Research Funds. We thank Mr. Anwar Qureshi for his excellent technical help in isolating rat ventricular myocytes. Authors cordially thank Dr. D. Hilgemann of University of Texas Southwestern Medical Center, for generously providing plasmids for NCX1 and YFP-NCX1.
PY - 2014/5
Y1 - 2014/5
N2 - Endocannabinoid anandamide (N-arachidonoyl ethanolamide; AEA) has been shown to cause negative inotropic and antiarrhythmic effects in ventricular myocytes. In this study, using whole-cell patch clamp technique, we have investigated the effects of AEA on cardiac Na+/Ca2+ exchanger (NCX1)-mediated currents. AEA suppressed NCX1 with an IC50 value of 4.7μM. Both inward and outward components of exchanger currents were suppressed by AEA equally. AEA inhibition was mimicked by the metabolically stable analogue, methanandamide (metAEA, 10μM) while it was not influenced by inhibition of fatty acid amide hydrolase with 1μM URB597 incubation. The effect of AEA, was not altered in the presence of cannabinoid receptor 1 and 2 antagonists AM251 (1μM) and AM630 (1μM), respectively. In addition, inhibition by AEA remained unchanged after pertussis toxin (PTX, 2μg/ml) treatment or following the inclusion of GDP-β-S (1mM) in pipette solution. Currents mediated by NCX1 expressed in HEK-293cells were also inhibited by 10μM AEA a partially reversible manner. Confocal microscopy images indicated that the intensity of YFP-NCX1 expression on cell surface was not altered by AEA. Collectively, the results indicate that AEA directly inhibits the function of NCX1 in rat ventricular myocytes and in HEK-293cells expressing NCX1.
AB - Endocannabinoid anandamide (N-arachidonoyl ethanolamide; AEA) has been shown to cause negative inotropic and antiarrhythmic effects in ventricular myocytes. In this study, using whole-cell patch clamp technique, we have investigated the effects of AEA on cardiac Na+/Ca2+ exchanger (NCX1)-mediated currents. AEA suppressed NCX1 with an IC50 value of 4.7μM. Both inward and outward components of exchanger currents were suppressed by AEA equally. AEA inhibition was mimicked by the metabolically stable analogue, methanandamide (metAEA, 10μM) while it was not influenced by inhibition of fatty acid amide hydrolase with 1μM URB597 incubation. The effect of AEA, was not altered in the presence of cannabinoid receptor 1 and 2 antagonists AM251 (1μM) and AM630 (1μM), respectively. In addition, inhibition by AEA remained unchanged after pertussis toxin (PTX, 2μg/ml) treatment or following the inclusion of GDP-β-S (1mM) in pipette solution. Currents mediated by NCX1 expressed in HEK-293cells were also inhibited by 10μM AEA a partially reversible manner. Confocal microscopy images indicated that the intensity of YFP-NCX1 expression on cell surface was not altered by AEA. Collectively, the results indicate that AEA directly inhibits the function of NCX1 in rat ventricular myocytes and in HEK-293cells expressing NCX1.
KW - Anandamide
KW - Whole-cell patch clamp technique
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U2 - 10.1016/j.ceca.2014.02.017
DO - 10.1016/j.ceca.2014.02.017
M3 - Article
C2 - 24674601
AN - SCOPUS:84899947849
SN - 0143-4160
VL - 55
SP - 231
EP - 237
JO - Cell Calcium
JF - Cell Calcium
IS - 5
ER -