Abstract
Human platelets must be stored at 22°C in blood banks, because of the well-known phenomenon of cold-induced activation. When human platelets are chilled below room temperature, they undergo shape change and vesicle secretion that resembles physiological agonist-mediated activation. The trigger for the cascade of events leading to platelet activation at hypothermic temperatures is not known, although an increase in the internal calcium concentration ([Ca](i)) due to passage of the platelet membranes through their thermotropic phase transition has been proposed. We report here that the fluorescent calcium-sensitive probe, Indo-1, has been used to estimate the internal calcium concentration of human platelets during a reduction in temperature from 20°C to 5°C at a rate of 0.5°C/min. An increase on the order of 100 nM was recorded. Almost all of the increase in [Ca2+](i) occurs during the chilling process, as incubation of platelets for 1 h at low temperature did not lead to a continued calcium concentration increase. The increase in [Ca2+](i) during chilling is likely to be due to more than a single mechanism, but might include some release of the calcium stores from the dense tubule system. Loading platelets with the calcium chelator BAPTA (1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid) dramatically reduced the increase in [Ca2+](i) seen during chilling. Antifreeze glycoproteins (AFGPs) isolated from the blood serum of Antarctic fishes, which are known to protect platelets from cold-induced activation, did not eliminate the rise in [Ca2+](i) during chilling, suggesting that signaling mechanisms are likely to be involved in cold-induced activation. Copyright (C) 1999 Elsevier Science B.V.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 349-360 |
| Number of pages | 12 |
| Journal | Biochimica et Biophysica Acta - Biomembranes |
| Volume | 1416 |
| Issue number | 1-2 |
| DOIs | |
| State | Published - Jan 12 1999 |
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Keywords
- Calcium
- Cold-induced activation
- Indo-1
- Membrane phase transition
- Platelet
ASJC Scopus subject areas
- Biochemistry
- Cell Biology
- Biophysics
Cite this
The internal calcium concentration of human platelets increases during chilling. / Oliver, Ann E.; Tablin, Fern; Walker, Naomi J.; Crowe, John H.
In: Biochimica et Biophysica Acta - Biomembranes, Vol. 1416, No. 1-2, 12.01.1999, p. 349-360.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The internal calcium concentration of human platelets increases during chilling
AU - Oliver, Ann E.
AU - Tablin, Fern
AU - Walker, Naomi J.
AU - Crowe, John H.
PY - 1999/1/12
Y1 - 1999/1/12
N2 - Human platelets must be stored at 22°C in blood banks, because of the well-known phenomenon of cold-induced activation. When human platelets are chilled below room temperature, they undergo shape change and vesicle secretion that resembles physiological agonist-mediated activation. The trigger for the cascade of events leading to platelet activation at hypothermic temperatures is not known, although an increase in the internal calcium concentration ([Ca](i)) due to passage of the platelet membranes through their thermotropic phase transition has been proposed. We report here that the fluorescent calcium-sensitive probe, Indo-1, has been used to estimate the internal calcium concentration of human platelets during a reduction in temperature from 20°C to 5°C at a rate of 0.5°C/min. An increase on the order of 100 nM was recorded. Almost all of the increase in [Ca2+](i) occurs during the chilling process, as incubation of platelets for 1 h at low temperature did not lead to a continued calcium concentration increase. The increase in [Ca2+](i) during chilling is likely to be due to more than a single mechanism, but might include some release of the calcium stores from the dense tubule system. Loading platelets with the calcium chelator BAPTA (1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid) dramatically reduced the increase in [Ca2+](i) seen during chilling. Antifreeze glycoproteins (AFGPs) isolated from the blood serum of Antarctic fishes, which are known to protect platelets from cold-induced activation, did not eliminate the rise in [Ca2+](i) during chilling, suggesting that signaling mechanisms are likely to be involved in cold-induced activation. Copyright (C) 1999 Elsevier Science B.V.
AB - Human platelets must be stored at 22°C in blood banks, because of the well-known phenomenon of cold-induced activation. When human platelets are chilled below room temperature, they undergo shape change and vesicle secretion that resembles physiological agonist-mediated activation. The trigger for the cascade of events leading to platelet activation at hypothermic temperatures is not known, although an increase in the internal calcium concentration ([Ca](i)) due to passage of the platelet membranes through their thermotropic phase transition has been proposed. We report here that the fluorescent calcium-sensitive probe, Indo-1, has been used to estimate the internal calcium concentration of human platelets during a reduction in temperature from 20°C to 5°C at a rate of 0.5°C/min. An increase on the order of 100 nM was recorded. Almost all of the increase in [Ca2+](i) occurs during the chilling process, as incubation of platelets for 1 h at low temperature did not lead to a continued calcium concentration increase. The increase in [Ca2+](i) during chilling is likely to be due to more than a single mechanism, but might include some release of the calcium stores from the dense tubule system. Loading platelets with the calcium chelator BAPTA (1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid) dramatically reduced the increase in [Ca2+](i) seen during chilling. Antifreeze glycoproteins (AFGPs) isolated from the blood serum of Antarctic fishes, which are known to protect platelets from cold-induced activation, did not eliminate the rise in [Ca2+](i) during chilling, suggesting that signaling mechanisms are likely to be involved in cold-induced activation. Copyright (C) 1999 Elsevier Science B.V.
KW - Calcium
KW - Cold-induced activation
KW - Indo-1
KW - Membrane phase transition
KW - Platelet
UR - http://www.scopus.com/inward/record.url?scp=0032921716&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032921716&partnerID=8YFLogxK
U2 - 10.1016/S0005-2736(98)00239-9
DO - 10.1016/S0005-2736(98)00239-9
M3 - Article
C2 - 9889395
AN - SCOPUS:0032921716
VL - 1416
SP - 349
EP - 360
JO - Biochimica et Biophysica Acta - Biomembranes
JF - Biochimica et Biophysica Acta - Biomembranes
SN - 0005-2736
IS - 1-2
ER -