Abstract
Small coronary arteries (SCA) from diabetic rats exhibit enhanced peroxynitrite (ONOO-) formation and concurrent impairment of voltage-dependent potassium (Kv) channel function. However, it is unclear whether ONOO- plays a causative role in this impairment. We hypothesized that functional loss of Kv channels in coronary smooth muscle cells (SMC) in diabetes is due to ONOO- with subsequent tyrosine nitration of Kv channel proteins. Diabetic rats and nondiabetic controls were treated with or without ebselen (Eb) for 4 wk. SCA were prepared for immunohistochemistry (IHC), immunoprecipitation (IP) followed by Western blot (WB), videomicroscopy, and patch-clamp analysis. IHC revealed excess ONOO- in SCA from diabetic rats. IP and WB revealed elevated nitration of the Kv1.2 α-subunit and reduced Kv1.2 protein expression in diabetic rats. Each of these changes was improved in Eb-treated rats. Protein nitration and Kv1.5 expression were unchanged in SCA from diabetic rats. Forskolin, a direct cAMP activator that induces Kv1 channel activity, dilated SCA from nondiabetic rats in a correolide (Cor; a selective Kv1 channel blocker)-sensitive fashion. Cor did not alter the reduced dilation to forskolin in diabetic rats; however, Eb partially restored the Cor-sensitive component of dilation. Basal K v current density and response to forskolin were improved in smooth muscle cells from Eb-treated DM rats. We conclude that enhanced nitrosative stress in diabetes mellitus contributes to Kv1 channel dysfunction in the coronary microcirculation. Eb may be beneficial for the therapeutic treatment of vascular complications in diabetes mellitus.
| Original language | English (US) |
|---|---|
| Journal | American Journal of Physiology - Heart and Circulatory Physiology |
| Volume | 293 |
| Issue number | 4 |
| DOIs | |
| State | Published - Oct 1 2007 |
| Externally published | Yes |
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Keywords
- Coronary circulation
- Diabetes
- Oxidative stress
- Peroxynitrite
ASJC Scopus subject areas
- Physiology
- Cardiology and Cardiovascular Medicine
- Physiology (medical)
Cite this
Ebselen reduces nitration and restores voltage-gated potassium channel function in small coronary arteries of diabetic rats. / Bubolz, Aaron H.; Wu, Qingping; Larsen, Brandon; Gutterman, David D.; Liu, Yanping.
In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 293, No. 4, 01.10.2007.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Ebselen reduces nitration and restores voltage-gated potassium channel function in small coronary arteries of diabetic rats
AU - Bubolz, Aaron H.
AU - Wu, Qingping
AU - Larsen, Brandon
AU - Gutterman, David D.
AU - Liu, Yanping
PY - 2007/10/1
Y1 - 2007/10/1
N2 - Small coronary arteries (SCA) from diabetic rats exhibit enhanced peroxynitrite (ONOO-) formation and concurrent impairment of voltage-dependent potassium (Kv) channel function. However, it is unclear whether ONOO- plays a causative role in this impairment. We hypothesized that functional loss of Kv channels in coronary smooth muscle cells (SMC) in diabetes is due to ONOO- with subsequent tyrosine nitration of Kv channel proteins. Diabetic rats and nondiabetic controls were treated with or without ebselen (Eb) for 4 wk. SCA were prepared for immunohistochemistry (IHC), immunoprecipitation (IP) followed by Western blot (WB), videomicroscopy, and patch-clamp analysis. IHC revealed excess ONOO- in SCA from diabetic rats. IP and WB revealed elevated nitration of the Kv1.2 α-subunit and reduced Kv1.2 protein expression in diabetic rats. Each of these changes was improved in Eb-treated rats. Protein nitration and Kv1.5 expression were unchanged in SCA from diabetic rats. Forskolin, a direct cAMP activator that induces Kv1 channel activity, dilated SCA from nondiabetic rats in a correolide (Cor; a selective Kv1 channel blocker)-sensitive fashion. Cor did not alter the reduced dilation to forskolin in diabetic rats; however, Eb partially restored the Cor-sensitive component of dilation. Basal K v current density and response to forskolin were improved in smooth muscle cells from Eb-treated DM rats. We conclude that enhanced nitrosative stress in diabetes mellitus contributes to Kv1 channel dysfunction in the coronary microcirculation. Eb may be beneficial for the therapeutic treatment of vascular complications in diabetes mellitus.
AB - Small coronary arteries (SCA) from diabetic rats exhibit enhanced peroxynitrite (ONOO-) formation and concurrent impairment of voltage-dependent potassium (Kv) channel function. However, it is unclear whether ONOO- plays a causative role in this impairment. We hypothesized that functional loss of Kv channels in coronary smooth muscle cells (SMC) in diabetes is due to ONOO- with subsequent tyrosine nitration of Kv channel proteins. Diabetic rats and nondiabetic controls were treated with or without ebselen (Eb) for 4 wk. SCA were prepared for immunohistochemistry (IHC), immunoprecipitation (IP) followed by Western blot (WB), videomicroscopy, and patch-clamp analysis. IHC revealed excess ONOO- in SCA from diabetic rats. IP and WB revealed elevated nitration of the Kv1.2 α-subunit and reduced Kv1.2 protein expression in diabetic rats. Each of these changes was improved in Eb-treated rats. Protein nitration and Kv1.5 expression were unchanged in SCA from diabetic rats. Forskolin, a direct cAMP activator that induces Kv1 channel activity, dilated SCA from nondiabetic rats in a correolide (Cor; a selective Kv1 channel blocker)-sensitive fashion. Cor did not alter the reduced dilation to forskolin in diabetic rats; however, Eb partially restored the Cor-sensitive component of dilation. Basal K v current density and response to forskolin were improved in smooth muscle cells from Eb-treated DM rats. We conclude that enhanced nitrosative stress in diabetes mellitus contributes to Kv1 channel dysfunction in the coronary microcirculation. Eb may be beneficial for the therapeutic treatment of vascular complications in diabetes mellitus.
KW - Coronary circulation
KW - Diabetes
KW - Oxidative stress
KW - Peroxynitrite
UR - http://www.scopus.com/inward/record.url?scp=35349000590&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=35349000590&partnerID=8YFLogxK
U2 - 10.1152/ajpheart.00717.2007
DO - 10.1152/ajpheart.00717.2007
M3 - Article
C2 - 17675568
AN - SCOPUS:35349000590
VL - 293
JO - American Journal of Physiology
JF - American Journal of Physiology
SN - 0363-6135
IS - 4
ER -