| First Author | Nimmegeers S | Year | 2007 |
| Journal | Cardiovasc Res | Volume | 76 |
| Issue | 1 | Pages | 149-59 |
| PubMed ID | 17610859 | Mgi Jnum | J:150855 |
| Mgi Id | MGI:3852093 | Doi | 10.1016/j.cardiores.2007.06.002 |
| Citation | Nimmegeers S, et al. (2007) Functional role of the soluble guanylyl cyclase alpha(1) subunit in vascular smooth muscle relaxation. Cardiovasc Res 76(1):149-59 |
| abstractText | OBJECTIVE: Soluble guanylyl cyclase (sGC), the predominant receptor for nitric oxide (NO), exists in 2 active isoforms (alpha(2)beta(1) and alpha(1)beta(1)). In vascular tissue sGCalpha(1)beta(1) is believed to be the most important. The aim of our study was to investigate the functional importance of the sGCalpha(1)-subunit in vasorelaxation. METHODS: Aortic and femoral artery segments from male and/or female sGCalpha(1)(-/-) mice and wild-type littermates were mounted in a small-vessel myograph for isometric tension recording. This was supplemented with biochemical measurements of the cGMP concentration and sGC enzyme activity. RESULTS: The functional importance of sGCalpha(1)beta(1) was demonstrated by the significantly decreased relaxing effects of acetylcholine (ACh), sodium nitroprusside (SNP), S-nitroso-N-acetylpenicillamine (SNAP), NO gas, YC-1, BAY 41-2272 and T-1032 in the sGCalpha(1)(-/-) mice of both genders. Moreover, the basal and SNP-stimulated cGMP levels and basal sGC activity were significantly lower in the sGCalpha(1)(-/-) mice. However, the relaxing effects of NO, BAY 41-2272 and YC-1 seen in blood vessels from sGCalpha(1)(-/-) mice indicate a role for an sGCalpha(1)beta(1)-independent mechanism. The increase in sGC activity after addition of BAY 41-2272 and the inhibition of the ACh-, SNP-, SNAP- and NO gas-induced response by the sGC inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) in the sGCalpha(1)(-/-) mice are observations suggesting that the sGCalpha(2)beta(1) isoform is also functionally active. However, the insignificant increase in cGMP in response to SNP and the non-upregulated sGCalpha(2) expression level in the sGCalpha(1)(-/-) mice suggest rather the involvement of (an) sGC-independent mechanism(s). CONCLUSIONS: We conclude that sGCalpha(1)beta(1) is involved in the vasorelaxation induced by NO-dependent and NO-independent sGC activators in both genders. However, the remaining relaxation seen in the sGCalpha(1)(-/-) mice suggests that besides sGCalpha(1)beta(1) also the minor isoform sGCalpha(2)beta(1) and/or (an) sGC-independent mechanism(s) play(s) a substantial role. |
