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J Appl Physiol (1985). 2013 Jan 15;114(2):252-61. doi: 10.1152/japplphysiol.01026.2011. Epub 2012 Nov 21.

Role of dual-specificity protein phosphatase-5 in modulating the myogenic response in rat cerebral arteries.

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Department of Physiology and Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.


The present study examined the role of the dual-specificity protein phosphatase-5 (DUSP-5) in the pressure-induced myogenic responses of organ-cultured cerebral arterial segments. In these studies, we initially compared freshly isolated and organ-cultured cerebral arterial segments with respect to responses to step increases in intravascular pressure, vasodilator and vasoconstrictor stimuli, activities of the large-conductance arterial Ca(2+)-activated K(+) (K(Ca)) single-channel current, and stable protein expression of DUSP-5 enzyme. The results demonstrate maintained pressure-dependent myogenic vasoconstriction, DUSP-5 protein expression, endothelium-dependent and -independent dilations, agonist-induced constriction, and unitary K(Ca) channel conductance in organ-cultured cerebral arterial segments similar to that in freshly isolated cerebral arteries. Furthermore, using a permeabilization transfection technique in organ-cultured cerebral arterial segments, gene-specific small interfering RNA (siRNA) induced knockdown of DUSP-5 mRNA and protein, which were associated with enhanced pressure-dependent cerebral arterial myogenic constriction and increased phosphorylation of PKC-βII. In addition, siRNA knockdown of DUSP-5 reduced levels of phosphorylated ROCK and ERK1 with no change in the level of phosphorylated ERK2. Pharmacological inhibition of ERK1/2 phosphorylation significantly attenuated pressure-induced myogenic constriction in cerebral arteries. The findings within the present studies illustrate that DUSP-5, native in cerebral arterial muscle cells, appears to regulate signaling of pressure-dependent myogenic cerebral arterial constriction, which is crucial for the maintenance of constant cerebral blood flow to the brain.

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