Microdialysis of norepinephrine into preoptic area of guinea pigs: characteristics of hypothermic effect.
Microdialysis of norepinephrine into preoptic area of guinea pigs: characteristics of hypothermic effect.
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DOI：
10.1152/ajpregu.1991.261.2.r378
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发表时间：
1991-08
期刊：
影响因子：
--
通讯作者：
N. Quan;L. Xin;C. Blatteis
中科院分区：
文献类型：
--
作者：
N. Quan;L. Xin;C. Blatteis
本研究旨在表征先前描述的去甲肾上腺素（NE）微透析到清醒豚鼠内侧视前区（MPO）的低温作用。为此，等渗无热原盐水 (PFS)、低渗 PFS、无活性（氧化）NE（高渗）、5-羟色胺（5-HT，10 和 20 微克/微升）、含或不含 2.4 mM Ca2+、10 微克/微升 NE 含 Ca2+ 以及不同剂量的 NE 对核心温度 (Tco) 的影响在 24 摄氏度的环境温度 (Ta) 下进行了一系列研究，对 NE（0.05-60 微克/微升）进行了比较。还测量了在寒冷（15 +/- 2 摄氏度）和温暖（31 +/- 1 摄氏度）Ta 以及夜间在 Ta 24 摄氏度下对 10 微克/微升 NE 的 Tco 响应。对溴酚蓝 (0.2%) 进行微透析以评估这些透析液的扩散程度。在 MPO 中发现了染色剂，其密度增加，但在连续微透析 3 小时内并未扩散到该区域之外。 PFS以及低渗和高渗溶液对Tco均没有明显影响。同样，两种剂量的 5-HT 都不会引起热反应。添加到 PFS 或 NE 中的 Ca2+ 不会改变对这两种溶液的通常 Tco 反应。 NE在Ta 24℃下引起剂量依赖性低温。在Ta 15℃下微透析的NE也引起Tco下降，但这些反应比24℃下的小。NE在温暖的Ta中没有影响。夜间，NE 引起类似的 Tco 下降，但透析结束后的恢复速度比白天慢。（摘要截断为 250 字）
This study was designed to characterize the previously described hypothermic action of norepinephrine (NE) microdialyzed into the medial preoptic area (MPO) of conscious guinea pigs. To this end, the effects on core temperature (Tco) of isotonic pyrogen-free saline (PFS), hypotonic PFS, inactive (oxidized) NE (hypertonic), 5-hydroxytryptamine (5-HT, 10 and 20 micrograms/microliter), PFS with or without 2.4 mM Ca2+, 10 micrograms/microliters NE with Ca2+, and various doses of NE (0.05-60 micrograms/microliters) were compared in a series of studies at an ambient temperature (Ta) of 24 degrees C. The Tco responses to 10 micrograms/microliters NE in a cold (15 +/- 2 degrees C) and a warm (31 +/- 1 degrees C) Ta and during the night in the dark in Ta 24 degrees C were also measured. Bromophenol blue (0.2%) was microdialyzed to assess the extent of diffusion of these dialysates. A stain was found in the MPO, which increased in density but did not spread beyond this region over 3 h of continuous microdialysis. Neither PFS nor the hypotonic and hypertonic solutions had any obvious effect on Tco. Similarly, neither dose of 5-HT evoked a thermal response. Ca2+ added to either PFS or NE did not alter the usual Tco responses to these two solutions. NE induced dose-dependent hypothermia in Ta 24 degrees C. NE microdialyzed in Ta 15 degrees C also produced Tco falls, but these responses were smaller than those in 24 degrees C. NE had no effect in the warm Ta. During the night, NE elicited similar Tco falls, but their recoveries after dialysis ended were slower than during the day.(ABSTRACT TRUNCATED AT 250 WORDS)