Nayeem Mohammed A, Ponnoth Dovenia S, Boegehold Matthew A, Zeldin Darryl C, Falck John R, Mustafa S Jamal
Dept. of Physiology and Pharmacology, Center for Interdisciplinary Research in Cardiovascular Sciences, Health Science Center-North, 1 Morgantown, WV 26506, USA.
Am J Physiol Regul Integr Comp Physiol. 2009 Mar;296(3):R567-74. doi: 10.1152/ajpregu.90798.2008. Epub 2008 Dec 24.
We hypothesize that A(2A) adenosine receptors (A(2A) AR) promote aortic relaxation in mice through cytochrome P450 (CYP)-epoxygenases and help to avoid salt sensitivity. Aortas from male mice maintained on a high-salt (HS; 7% NaCl) or normal-salt (NS; 0.45% NaCl) diet for 4-5 wks were used. Concentration-response curves (10(-11)-10(-5) M) for 5'-N-ethylcarboxamidoadenosine (NECA; a nonselective adenosine analog) and CGS 21680 (A(2A) AR agonist) were obtained with different antagonists including ZM 241385 (A(2A) AR antagonist; 10(-6) M), SCH 58261 (A(2A) AR antagonist; 10(-6) M), N(omega)-nitro-l-arginine methyl ester (l-NAME; endothelial nitric oxide synthase inhibitor; 10(-4) M) and inhibitors including methylsulfonyl-propargyloxyphenylhexanamide (MS-PPOH; CYP epoxygenases inhibitor; 10(-5)M), 14,15-epoxyeicosa-5(z)-enoic acid (14,15-EEZE; EET antagonist; 10(-5)M), dibromo-dodecenyl-methylsulfimide (DDMS; CYP4A inhibitor; 10(-5)M), and HET0016 (20-HETE inhibitor; 10(-5)M). At 10(-7) M of NECA, significant relaxation in HS (+22.58 +/- 3.12%) was observed compared with contraction in NS (-10.62 +/- 6.27%, P < 0.05). ZM 241385 changed the NECA response to contraction (P < 0.05) in HS. At 10(-7) M of CGS 21680, significant relaxation in HS (+32.04 +/- 3.08%) was observed compared with NS (+10.45 +/- 1.34%, P < 0.05). SCH 58261, l-NAME, MS-PPOH, and 14,15-EEZE changed the CGS 21680-induced relaxation to contraction (P < 0.05) in HS. Interestingly, DDMS and HET0016 changed CGS 21680 response to relaxation (P < 0.05) in NS; however, there was no significant difference found between DDMS, HET0016-treated HS and NS vs. nontreated HS group (P > 0.05). CYP2C29 protein was 55% and 74% upregulated in HS vs. NS (P < 0.05) mice aorta and kidney, respectively. CYP4A protein was 30.30% and 35.70% upregulated in NS vs. HS (P < 0.05) mice aorta and kidneys, respectively. A(1) AR was downregulated, whereas A(2A) AR was upregulated in HS compared with NS. These data suggest that HS may activate CYP2C29 via A(2A) AR, causing relaxation, whereas NS may contribute to the upregulation of CYP4A causing contraction.
我们推测，A（2A）型腺苷受体（A（2A）AR）通过细胞色素P450（CYP）-环氧合酶促进小鼠主动脉舒张，并有助于避免盐敏感性。使用在高盐（HS；7% NaCl）或正常盐（NS；0.45% NaCl）饮食中维持4-5周的雄性小鼠的主动脉。用不同的拮抗剂获得5'-N-乙基羧酰胺腺苷（NECA；一种非选择性腺苷类似物）和CGS 21680（A（2A）AR激动剂）的浓度-反应曲线（10（-11）-10（-5）M），这些拮抗剂包括ZM 241385（A（2A）AR拮抗剂；10（-6）M）、SCH 58261（A（2A）AR拮抗剂；10（-6）M）、N（ω）-硝基-L-精氨酸甲酯（L-NAME；内皮型一氧化氮合酶抑制剂；10（-4）M）以及抑制剂，如甲磺酰基-炔丙氧基苯基己酰胺（MS-PPOH；CYP环氧合酶抑制剂；10（-5）M）、14,15-环氧二十碳-5（Z）-烯酸（14,15-EEZE；EET拮抗剂；10（-5）M）、二溴十二碳烯基甲基磺酰亚胺（DDMS；CYP4A抑制剂；10（-5）M）和HET0016（20-HETE抑制剂；10（-5）M）。在NECA浓度为10（-7）M时，与NS组的收缩（-10.62±6.27%，P<0.05）相比，HS组观察到显著的舒张（+22.58±3.12%）。ZM 241385改变了HS组中NECA的反应，使其变为收缩（P<0.05）。在CGS 21680浓度为10（-7）M时，与NS组（+10.45±1.34%，P<0.05）相比，HS组观察到显著的舒张（+32.04±3.08%）。SCH 58261、L-NAME、MS-PPOH和14,15-EEZE改变了HS组中CGS 21680诱导的舒张，使其变为收缩（P<0.05）。有趣的是，DDMS和HET0016改变了NS组中CGS 21680的舒张反应（P<0.05）；然而，DDMS、HET0016处理的HS组与未处理的HS组相比，NS组与未处理的HS组之间未发现显著差异（P>0.05）。与NS组相比，HS组小鼠主动脉和肾脏中CYP2C29蛋白分别上调55%和74%（P<0.05）。与HS组相比，NS组小鼠主动脉和肾脏中CYP4A蛋白分别上调30.30%和35.70%（P<0.05）。与NS组相比，HS组中A（1）AR下调，而A（2A）AR上调。这些数据表明，HS可能通过A（2A）AR激活CYP2C29，导致舒张，而NS可能导致CYP4A上调，引起收缩。
