Inhibition of cystathionine-gamma lyase dampens vasoconstriction in mouse and human intracerebral arterioles

AimIn extracerebral vascular beds cystathionine-gamma lyase (CSE) activity plays a vasodilatory role but the role of this hydrogen sulfide (H2S) producing enzyme in the intracerebral arterioles remain poorly understood. We hypothesized a similar function in the intracerebral arterioles. MethodsIntracerebral arterioles were isolated from wild type C57BL/6J mouse (9-12 months old) brains and from human brain biopsies. The function (contractility and secondary dilatation) of the intracerebral arterioles was tested ex vivo by pressure myography using a perfusion set-up. Reverse transcription polymerase chain reaction was used for detecting CSE expression. ResultsCSE is expressed in human and mouse intracerebral arterioles. CSE inhibition with L-propargylglycine (PAG) significantly dampened the K+-induced vasoconstriction in intracerebral arterioles of both species (% of maximum contraction: in human control: 45.4 & PLUSMN; 2.7 versus PAG: 27 & PLUSMN; 5.2 and in mouse control: 50 & PLUSMN; 1.5 versus PAG: 33 & PLUSMN; 5.2) but did not affect the secondary dilatation. This effect of PAG was significantly reversed by the H2S donor sodium hydrosulfide (NaSH) in human (PAG + NaSH: 38.8 & PLUSMN; 7.2) and mouse (PAG + NaSH: 41.7 & PLUSMN; 3.1) arterioles, respectively. The endothelial NO synthase (eNOS) inhibitor, N & omega;-Nitro-l-arginine methyl ester (L-NAME), and the inhibitor of soluble guanylate cyclase (sGC), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) reversed the effect of PAG on the K+-induced vasoconstriction in the mouse arterioles and attenuated the K+-induced secondary dilatation significantly. ConclusionCSE contributes to the K+-induced vasoconstriction via a mechanism involving H2S, eNOS, and sGC whereas the secondary dilatation is regulated by eNOS and sGC but not by CSE.

Automated summary

This study explores the role of cystathionine-gamma lyase(CSE), an enzyme producing hydrogen sulfide (H2S), in intracerebral arterioles. The results suggest that CSE plays a role in regulating vasoconstriction through H2S, eNOS, and sGC mechanisms, while secondary dilatation is regulated by eNOS and sGC but not by CSE.