Abstract
We tested the hypothesis that Ca2+ influx into endothelial cells forming the walls of intact venular microvessels was increased when the cell membranes were hyperpolarized. Cytoplasmic free Ca2+ concentration ([Ca2+](i)) was measured after the endothelial cells forming the microvessel wall were loaded with fura 2, endothelial cell membrane potential was measured with the membrane potential dye bis-oxonol, and hydraulic conductivity (L(p)) of the vessels was measured by the modified Landis technique to follow changes in microvessel permeability. When microvessels were exposed to low-K+ (0.1 mM) Ringer solution, the membrane of the endothelial cells was hyperpolarized ~27 mV and [Ca2+](i) increased from 47 nM to a peak value of 151 ± 28 nM. Under the same experimental conditions, L(p) increased to a peak 6.3 times control. In the presence of ionomycin (5 μM), the initial peak [Ca2+](i) measured with low-K+ Ringer solution was 347 ± 58 nM compared with 252 ± 58 nM with ionophore and normal Ringer solution. The corresponding initial increases in L(p) were 28 times control and 10 times control, respectively. The results conform to the hypothesis that vasoactive substances that hyperpolarize the endothelial cell membrane may initiate and/or potentiate the inflammatory response in venular microvessels.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2288-2297 |
| Number of pages | 10 |
| Journal | Journal of Applied Physiology |
| Volume | 76 |
| Issue number | 6 |
| State | Published - 1994 |
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Keywords
- calcium ionophore
- capillary hydraulic conductivity
- capillary permeability
- conductive calcium pathways
- cytoplasmic free calcium concentration
- fura 2 measurement
- ionomycin
- membrane potential
- single perfused microvessels
ASJC Scopus subject areas
- Endocrinology
- Physiology
- Orthopedics and Sports Medicine
- Physical Therapy, Sports Therapy and Rehabilitation
Cite this
Endothelial cell hyperpolarization increases [Ca2+](i) and venular microvessel permeability. / He, P.; Curry, F. E.
In: Journal of Applied Physiology, Vol. 76, No. 6, 1994, p. 2288-2297.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Endothelial cell hyperpolarization increases [Ca2+](i) and venular microvessel permeability
AU - He, P.
AU - Curry, F. E.
PY - 1994
Y1 - 1994
N2 - We tested the hypothesis that Ca2+ influx into endothelial cells forming the walls of intact venular microvessels was increased when the cell membranes were hyperpolarized. Cytoplasmic free Ca2+ concentration ([Ca2+](i)) was measured after the endothelial cells forming the microvessel wall were loaded with fura 2, endothelial cell membrane potential was measured with the membrane potential dye bis-oxonol, and hydraulic conductivity (L(p)) of the vessels was measured by the modified Landis technique to follow changes in microvessel permeability. When microvessels were exposed to low-K+ (0.1 mM) Ringer solution, the membrane of the endothelial cells was hyperpolarized ~27 mV and [Ca2+](i) increased from 47 nM to a peak value of 151 ± 28 nM. Under the same experimental conditions, L(p) increased to a peak 6.3 times control. In the presence of ionomycin (5 μM), the initial peak [Ca2+](i) measured with low-K+ Ringer solution was 347 ± 58 nM compared with 252 ± 58 nM with ionophore and normal Ringer solution. The corresponding initial increases in L(p) were 28 times control and 10 times control, respectively. The results conform to the hypothesis that vasoactive substances that hyperpolarize the endothelial cell membrane may initiate and/or potentiate the inflammatory response in venular microvessels.
AB - We tested the hypothesis that Ca2+ influx into endothelial cells forming the walls of intact venular microvessels was increased when the cell membranes were hyperpolarized. Cytoplasmic free Ca2+ concentration ([Ca2+](i)) was measured after the endothelial cells forming the microvessel wall were loaded with fura 2, endothelial cell membrane potential was measured with the membrane potential dye bis-oxonol, and hydraulic conductivity (L(p)) of the vessels was measured by the modified Landis technique to follow changes in microvessel permeability. When microvessels were exposed to low-K+ (0.1 mM) Ringer solution, the membrane of the endothelial cells was hyperpolarized ~27 mV and [Ca2+](i) increased from 47 nM to a peak value of 151 ± 28 nM. Under the same experimental conditions, L(p) increased to a peak 6.3 times control. In the presence of ionomycin (5 μM), the initial peak [Ca2+](i) measured with low-K+ Ringer solution was 347 ± 58 nM compared with 252 ± 58 nM with ionophore and normal Ringer solution. The corresponding initial increases in L(p) were 28 times control and 10 times control, respectively. The results conform to the hypothesis that vasoactive substances that hyperpolarize the endothelial cell membrane may initiate and/or potentiate the inflammatory response in venular microvessels.
KW - calcium ionophore
KW - capillary hydraulic conductivity
KW - capillary permeability
KW - conductive calcium pathways
KW - cytoplasmic free calcium concentration
KW - fura 2 measurement
KW - ionomycin
KW - membrane potential
KW - single perfused microvessels
UR - http://www.scopus.com/inward/record.url?scp=0028277409&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0028277409&partnerID=8YFLogxK
M3 - Article
VL - 76
SP - 2288
EP - 2297
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
SN - 8750-7587
IS - 6
ER -