Abstract
In hypertension, membrane potassium permeability and vascular reactivity are increased. This study characterizes a potassium-selective channel and contractions to barium, a potassium channel inhibitor, in vascular smooth muscle (tail artery) from spontaneously hypertensive stroke-prone rats (SHRSP) and normotensive Wistar-Kyoto (WKY) rats. Smooth muscle cells were isolated by enzymatic digestion, and potassium channel activity was characterized by using patch-clamp technique (inside-out configuration). Isometric contractile activity was evaluated in helically cut arterial strips by using standard muscle bath methodology. In membrane patches, a voltage-gated, calcium-insensitive, potassium-selective channel of large conductance (200 picosiemens) was observed. The channel did not conduct sodium or rubidium. Barium (10−6to 10−4M) produced a dose-dependent blockade of channel activity. These channel characteristics did not differ in SHRSP and WKY rat cells. After treatment with 35 mM KCI, barium (10−5to 10−3M) caused greater contractions in SHRSP arteries compared with arteries in WKY rats. The contractions to barium were markedly attenuated in calcium-free solution, and nifedipine and verapamil abolished contractions induced by barium in depolarizing solution. We conclude that increased vascular reactivity to barium in SHRSP arteries Is not due to an alteration in the biophysical properties of the potassium channel studied.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 687-691 |
| Number of pages | 5 |
| Journal | Hypertension |
| Volume | 15 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jun 1990 |
| Externally published | Yes |
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Keywords
- Barium
- Potassium
- Stroke-prone spontaneously hypertensive rats
- Vascular smooth muscle
ASJC Scopus subject areas
- Internal Medicine
Cite this
Potassium channels and vascular reactivity in genetically hypertensive rats. / Furspan, Philip B.; Webb, R. Clinton.
In: Hypertension, Vol. 15, No. 6, 06.1990, p. 687-691.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Potassium channels and vascular reactivity in genetically hypertensive rats
AU - Furspan, Philip B.
AU - Webb, R. Clinton
PY - 1990/6
Y1 - 1990/6
N2 - In hypertension, membrane potassium permeability and vascular reactivity are increased. This study characterizes a potassium-selective channel and contractions to barium, a potassium channel inhibitor, in vascular smooth muscle (tail artery) from spontaneously hypertensive stroke-prone rats (SHRSP) and normotensive Wistar-Kyoto (WKY) rats. Smooth muscle cells were isolated by enzymatic digestion, and potassium channel activity was characterized by using patch-clamp technique (inside-out configuration). Isometric contractile activity was evaluated in helically cut arterial strips by using standard muscle bath methodology. In membrane patches, a voltage-gated, calcium-insensitive, potassium-selective channel of large conductance (200 picosiemens) was observed. The channel did not conduct sodium or rubidium. Barium (10−6to 10−4M) produced a dose-dependent blockade of channel activity. These channel characteristics did not differ in SHRSP and WKY rat cells. After treatment with 35 mM KCI, barium (10−5to 10−3M) caused greater contractions in SHRSP arteries compared with arteries in WKY rats. The contractions to barium were markedly attenuated in calcium-free solution, and nifedipine and verapamil abolished contractions induced by barium in depolarizing solution. We conclude that increased vascular reactivity to barium in SHRSP arteries Is not due to an alteration in the biophysical properties of the potassium channel studied.
AB - In hypertension, membrane potassium permeability and vascular reactivity are increased. This study characterizes a potassium-selective channel and contractions to barium, a potassium channel inhibitor, in vascular smooth muscle (tail artery) from spontaneously hypertensive stroke-prone rats (SHRSP) and normotensive Wistar-Kyoto (WKY) rats. Smooth muscle cells were isolated by enzymatic digestion, and potassium channel activity was characterized by using patch-clamp technique (inside-out configuration). Isometric contractile activity was evaluated in helically cut arterial strips by using standard muscle bath methodology. In membrane patches, a voltage-gated, calcium-insensitive, potassium-selective channel of large conductance (200 picosiemens) was observed. The channel did not conduct sodium or rubidium. Barium (10−6to 10−4M) produced a dose-dependent blockade of channel activity. These channel characteristics did not differ in SHRSP and WKY rat cells. After treatment with 35 mM KCI, barium (10−5to 10−3M) caused greater contractions in SHRSP arteries compared with arteries in WKY rats. The contractions to barium were markedly attenuated in calcium-free solution, and nifedipine and verapamil abolished contractions induced by barium in depolarizing solution. We conclude that increased vascular reactivity to barium in SHRSP arteries Is not due to an alteration in the biophysical properties of the potassium channel studied.
KW - Barium
KW - Potassium
KW - Stroke-prone spontaneously hypertensive rats
KW - Vascular smooth muscle
UR - http://www.scopus.com/inward/record.url?scp=0025365292&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0025365292&partnerID=8YFLogxK
U2 - 10.1161/01.HYP.15.6.687
DO - 10.1161/01.HYP.15.6.687
M3 - Article
C2 - 2351424
AN - SCOPUS:0025365292
VL - 15
SP - 687
EP - 691
JO - Hypertension
JF - Hypertension
SN - 0194-911X
IS - 6
ER -