Kv channel subunits that contribute to voltage-gated K+ current in renal vascular smooth muscle.
The rat renal arterial vasculature displays differences in K(+) channel current phenotypes along its length. Small arcuate to cortical radial arteries express a delayed rectifier phenotype, while the predominant Kv current in larger arcuate and interlobar arteries is composed of both transient and sustained components. We sought to determine whether Kvalpha subunits in the rat renal interlobar and arcuate arteries form heterotetramers, which may account for the unique currents, and whether modulatory Kvbeta subunits are present in renal vascular smooth muscle cells. RT-PCR indicated the presence of several different Kvalpha subunit isoform transcripts. Co-immunoprecipitation with immunoblotting and immunohistochemical evidence suggests that a portion of the K(+) current phenotype is a heteromultimer containing delayed-rectifier Kv1.2 and A-type Kv1.4 channel subunits. RT-PCR and immunoblot analyses also demonstrated the presence of both Kvbeta1.2 and Kvbeta1.3 in renal arteries. These results suggest that heteromultimeric formation of Kvalpha subunits and the presence of modulatory Kvbeta subunits are important factors in mediating Kv currents in the renal microvasculature and suggest a potentially critical role for these channel subunits in blood pressure regulation.
Fergus
Daniel J
DJ
Department of Physiology and Biophysics, 5-660 Bowen Science Building, University of Iowa, Iowa City, Iowa 52242, USA.
Martens
Jeffrey R
JR
England
Sarah K
SK
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D051668:Delayed Rectifier Potassium Channels; D015870:Gene Expression / Q000502:physiology; D015640:Ion Channel Gating / Q000502:physiology*; D051662:Kv1.1 Potassium Channel; D051663:Kv1.2 Potassium Channel; D051664:Kv1.3 Potassium Channel; D051665:Kv1.4 Potassium Channel; D051666:Kv1.5 Potassium Channel; D008297:Male; D008564:Membrane Potentials / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D015221:Potassium Channels / Q000235:genetics* / Q000378:metabolism*; D024642:Potassium Channels, Voltage-Gated; D051381:Rats; D011921:Rats, Inbred WKY; D012077:Renal Artery / Q000502:physiology*
D051668:Delayed Rectifier Potassium Channels; C496972:Kcna2 protein, rat; C496975:Kcna3 protein, rat; C496979:Kcna4 protein, rat; C496983:Kcna5 protein, rat; D051663:Kv1.2 Potassium Channel; D051664:Kv1.3 Potassium Channel; D051665:Kv1.4 Potassium Channel; D051666:Kv1.5 Potassium Channel; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D051662:Kv1.1 Potassium Channel