Abstract
This study aimed to determine a target temperature for intraischemic hypothermia that can block increases in extracellular glutamate levels. Two groups of 10 rats each formed the normothermia and intraischemic hypothermia groups. Extracellular glutamate levels, the extracellular potential, and the cerebral blood flow were measured at the adjacent site in the right parietal cerebral cortex. Cerebral ischemia was induced by occlusion of the bilateral common carotid arteries and hypotension. In the intraischemic hypothermia group, brain hypothermia was initiated immediately after the onset of membrane potential loss. In the normothermia group, extracellular glutamate levels began to increase simultaneously with the onset of membrane potential loss and reached a maximum level of 341.8 ± 153.1 μmol·L-1. A decrease in extracellular glutamate levels was observed simultaneously with the onset of membrane potential recovery. In the intraischemic hypothermia group, extracellular glutamate levels initially began to increase, similarly to those in the normothermia group, but subsequently plateaued at 140.5 ± 105.4 μmol·L-1, when the brain temperature had decreased to <32.6°C ± 0.9°C. A decrease in extracellular glutamate levels was observed simultaneously with the onset of membrane potential recovery, similarly to the findings in the normothermia group. The rate of decrease in extracellular glutamate levels was the same in both groups (-36.6 and-36.0 μmol·L-1 in the normothermia and intraischemic hypothermia groups, respectively). In conclusion, the target temperature for blocking glutamate release during intraischemic hypothermia was found to be 32.6°C ± 0.9°C. Our results suggest that the induction of intraischemic hypothermia can maintain low glutamate levels without disrupting glutamate reuptake. Institutional protocol number: OKU-2016146.
| Original language | English |
|---|---|
| Pages (from-to) | 83-89 |
| Number of pages | 7 |
| Journal | Therapeutic hypothermia and temperature management |
| Volume | 8 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Jun 1 2018 |
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Keywords
- brain ischemia
- glutamate
- glutamate transporter
- hypothermia
- membrane potential
- temperature
ASJC Scopus subject areas
- Critical Care and Intensive Care Medicine
- Anesthesiology and Pain Medicine
Cite this
Determination of the target temperature required to block increases in extracellular glutamate levels during intraischemic hypothermia. / Sato, Sachiko; Takeda, Yoshimasa; Mizoue, Ryoichi; Kawase, Hirokazu; Fushimi, Miki; Shimizu, Tomohisa; Morimatsu, Hiroshi.
In: Therapeutic hypothermia and temperature management, Vol. 8, No. 2, 01.06.2018, p. 83-89.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Determination of the target temperature required to block increases in extracellular glutamate levels during intraischemic hypothermia
AU - Sato, Sachiko
AU - Takeda, Yoshimasa
AU - Mizoue, Ryoichi
AU - Kawase, Hirokazu
AU - Fushimi, Miki
AU - Shimizu, Tomohisa
AU - Morimatsu, Hiroshi
PY - 2018/6/1
Y1 - 2018/6/1
N2 - This study aimed to determine a target temperature for intraischemic hypothermia that can block increases in extracellular glutamate levels. Two groups of 10 rats each formed the normothermia and intraischemic hypothermia groups. Extracellular glutamate levels, the extracellular potential, and the cerebral blood flow were measured at the adjacent site in the right parietal cerebral cortex. Cerebral ischemia was induced by occlusion of the bilateral common carotid arteries and hypotension. In the intraischemic hypothermia group, brain hypothermia was initiated immediately after the onset of membrane potential loss. In the normothermia group, extracellular glutamate levels began to increase simultaneously with the onset of membrane potential loss and reached a maximum level of 341.8 ± 153.1 μmol·L-1. A decrease in extracellular glutamate levels was observed simultaneously with the onset of membrane potential recovery. In the intraischemic hypothermia group, extracellular glutamate levels initially began to increase, similarly to those in the normothermia group, but subsequently plateaued at 140.5 ± 105.4 μmol·L-1, when the brain temperature had decreased to <32.6°C ± 0.9°C. A decrease in extracellular glutamate levels was observed simultaneously with the onset of membrane potential recovery, similarly to the findings in the normothermia group. The rate of decrease in extracellular glutamate levels was the same in both groups (-36.6 and-36.0 μmol·L-1 in the normothermia and intraischemic hypothermia groups, respectively). In conclusion, the target temperature for blocking glutamate release during intraischemic hypothermia was found to be 32.6°C ± 0.9°C. Our results suggest that the induction of intraischemic hypothermia can maintain low glutamate levels without disrupting glutamate reuptake. Institutional protocol number: OKU-2016146.
AB - This study aimed to determine a target temperature for intraischemic hypothermia that can block increases in extracellular glutamate levels. Two groups of 10 rats each formed the normothermia and intraischemic hypothermia groups. Extracellular glutamate levels, the extracellular potential, and the cerebral blood flow were measured at the adjacent site in the right parietal cerebral cortex. Cerebral ischemia was induced by occlusion of the bilateral common carotid arteries and hypotension. In the intraischemic hypothermia group, brain hypothermia was initiated immediately after the onset of membrane potential loss. In the normothermia group, extracellular glutamate levels began to increase simultaneously with the onset of membrane potential loss and reached a maximum level of 341.8 ± 153.1 μmol·L-1. A decrease in extracellular glutamate levels was observed simultaneously with the onset of membrane potential recovery. In the intraischemic hypothermia group, extracellular glutamate levels initially began to increase, similarly to those in the normothermia group, but subsequently plateaued at 140.5 ± 105.4 μmol·L-1, when the brain temperature had decreased to <32.6°C ± 0.9°C. A decrease in extracellular glutamate levels was observed simultaneously with the onset of membrane potential recovery, similarly to the findings in the normothermia group. The rate of decrease in extracellular glutamate levels was the same in both groups (-36.6 and-36.0 μmol·L-1 in the normothermia and intraischemic hypothermia groups, respectively). In conclusion, the target temperature for blocking glutamate release during intraischemic hypothermia was found to be 32.6°C ± 0.9°C. Our results suggest that the induction of intraischemic hypothermia can maintain low glutamate levels without disrupting glutamate reuptake. Institutional protocol number: OKU-2016146.
KW - brain ischemia
KW - glutamate
KW - glutamate transporter
KW - hypothermia
KW - membrane potential
KW - temperature
UR - http://www.scopus.com/inward/record.url?scp=85048239486&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85048239486&partnerID=8YFLogxK
U2 - 10.1089/ther.2017.0041
DO - 10.1089/ther.2017.0041
M3 - Article
C2 - 29406818
AN - SCOPUS:85048239486
VL - 8
SP - 83
EP - 89
JO - Therapeutic hypothermia and temperature management
JF - Therapeutic hypothermia and temperature management
SN - 2153-7658
IS - 2
ER -