Voltage gated K+ channel expression in arteries of Wistar-Kyoto and spontaneously hypertensive rats.

BACKGROUND

We have previously demonstrated differences in the gene expression of voltage-gated K v1.X channel alpha-subunits in arteries from Wistar-Kyoto rats (WKYs) and spontaneously hypertensive rats (SHRs). The purpose of this study was to test the hypothesis that these differences are also present at the protein level.

METHODS

Proteins were isolated from the aorta, mesenteric (MAs) and tail arteries (TAs) of 12- to 15-week-old male WKY and SHR, and analyzed by immunoblotting. K(v) currents were recorded from MA myocytes by patch clamp methods.

RESULTS

Expression of Kv1.2, Kv1.5, and Kv2.1 was higher in MAs but was not different in aortas of SHRs as compared to WKYs. In the TA, expression of Kv1.2 and Kv1.5 was higher while that of Kv2.1 was lower in SHR compared to WKY. In the MA, the larger expression of an 80 kDa species of Kv1.2 in SHRs was associated with a lower expression of a 60 kDa species. Kv2.1 gene expression was larger in MAs from SHRs but not different in TAs. K(v) currents associated with Kv1.X and Kv2.1 channels were both larger in MA myocytes from SHRs but less than expected based upon differences in K(v) alpha-subunit protein expression.

CONCLUSIONS

For the MA, K(v) protein expression and current components between WKYs and SHRs were qualitatively consistent, but differences in gene and protein expression were not closely correlated. The higher expression of K(v) subunits in small mesenteric arteries (SMAs) of SHR would tend to maintain normal myogenic activity and vasoconstrictor reserve, and could be viewed as a form of homeostatic remodeling.