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Hemodynamic Response to Forepaw Stimulation in Anesthetized Mice Somatosensory Cortex
https://repo.qst.go.jp/records/68957
https://repo.qst.go.jp/records/689575d862c9d-3d72-49a7-a5ca-7dbfe3b6a49f
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2007-06-04 | |||||
| タイトル | ||||||
| タイトル | Hemodynamic Response to Forepaw Stimulation in Anesthetized Mice Somatosensory Cortex | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_c94f | |||||
| 資源タイプ | conference object | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
Masamoto, Kazuto
× Masamoto, Kazuto× et.al× 正本 和人 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Aim: Genetically altered mice are a potentially powerful tool to elucidate the molecular basis of neuro-vascular coupling mechanism. However, neural activity-induced hemodynamic responses in anesthetized murine cortex remains uncharacterized, which hampers the use of a mice model for functional imaging studies (e.g., fMRI and optical imaging). In the present study, hemodynamic responses to forepaw stimulation in the mice somatosensory cortex were characterized under pentobarbital, ketamine-xylazine, and isoflurane anesthesia, all of which are generally used for repeated animal experiments. \nMaterials and methods: A total of thirteen male C57B6J mice (23-35 g) were divided into three groups. First group (N = 4) was induced with pentobarbital anesthesia (an initial dose of 90 mg/kg i.p. and supplemental dose of 30-45 mg/kg/h i.p.). Second group (N = 6) was induced with a cocktail of ketamine and xylazine (an initial dose of 60 mg/kg and 10 mg/kg i.m., respectively, and supplementally injected with only ketamine 20 mg/kg i.m. every 20-40 min.). The animals in the third group (N = 3) were ventilated with a mixture of isoflurane (4% for induction and 1.3-1.5% for experiments) and air with supplemental oxygen (a total of 30-35%). Animals in the isoflurane group were intubated and mechanically ventilated, whereas the other two groups breathed spontaneously. After the skin covering the skull was removed, oil was immediately placed to preserve the integrity of the skull. First, intrinsic optical imaging (620-nm wavelength) was performed for the localization of the forepaw area in the primary somatosensory cortex. Then, hemodynamic response was measured with laser-Doppler flowmetry (LDF) on the activation focus induced by electrical forepaw stimulation (rectangular pulses with 0.5-ms pulse width and 0.8-mA current). Stimulation duration was fixed at 10 sec for all experiments and stimulation rate (frequency) was varied (2, 4, 6, 8 and 12 Hz). Preliminary experiments determined a pulse width and current that would not elicit a pain response from the animal. \nResults and discussion: All animal groups showed clear localization of forepaw area in 620-nm optical imaging. The clearest contrast of activation area was observed with ketamine-xylazine group. Under pentobarbital anesthesia, the hemodynamic response increased with an increase in stimulation frequency. The peak of 10 +/- 12% (Mean +/- SD, N = 4) signal change in LDF was observed at stimulation with 12 Hz. Under ketamine-xylazine anesthesia, the highest signal change (13 +/- 4% at peak) was observed at stimulation with 6 Hz. These results indicate that the optimum frequency differs depending on the anesthesia used, which was consistent with our previous results obtained in rats (Masamoto et al., 2006). In isoflurane-anesthetized group, however, no significant hemodynamic response was observed for any stimulation frequency. This result indicates that the isoflurane may be not a good agent for functional imaging studies with mice, which was not the case in rats anesthetized with isoflurane (Masamoto et al., 2006). In conclusion, mice anesthetized with pentobarbital or ketamine-xylazine can be used for repeated functional imaging studies, which make possible to probe the mechanism of neurovascular coupling with a specific molecular basis. |
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| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | Brain'07 and BrainPET'07 | |||||
| 発表年月日 | ||||||
| 日付 | 2007-05-24 | |||||
| 日付タイプ | Issued | |||||
