Rapid adenosine release in the nucleus tractus solitarii during defence response in rats:: real-time measurement in vivo
Rapid adenosine release in the nucleus tractus solitarii during defence response in rats:: real-time measurement in vivo
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DOI：
10.1113/jphysiol.2002.024158
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发表时间：
2002-10-01
影响因子：
5.5
通讯作者：
Spyer, KM
中科院分区：
文献类型：
--
作者：
Dale, N;Gourine, AV;Spyer, KM
我们已经测量了释放腺苷和肌苷从背表面的脑干和从内孤束核（NTS）在下丘脑刺激引起的麻醉大鼠的防御反应。在脑干表面，只有释放肌苷检测到下丘脑防御区刺激。通过加入胞外-5 ′-核苷酸酶抑制剂α，β-亚甲基ADP（200 μ M），这种肌苷信号大大降低，表明肌苷是由细胞外空间中通过ATP的预先释放产生的腺苷产生的。通过将一个微电极生物传感器到NTS的立体定位控制下，我们已经记录了这个核内的腺苷释放。与脑干表面相比，刺激下丘脑防御区后，腺苷快速增加，仅伴随着肌苷水平的较小变化。下丘脑刺激后释放的腺苷主要局限于一个狭窄的区域的NTS约500妈妈的长度周围的水平obex。有趣的是，腺苷的释放是可耗尽的：当防御反应在短时间间隔内被诱发时，在第二次刺激时释放的腺苷要少得多。我们的新技术提供了前所未有的实时测量和定位腺苷在体内的释放，并证明腺苷在正确的时间和足够的量释放，以促进心血管成分的防御反应。
We have measured the release of adenosine and inosine from the dorsal surface of the brainstem and from within the nucleus tractus solitarii (NTS) during the defence response evoked by hypothalamic stimulation in the anaesthetised rat. At the surface of the brainstem, only release of inosine was detected on hypothalamic defence area stimulation. This inosine signal was greatly reduced by addition of the ecto-5'-nucleotidase inhibitor alpha,beta-methylene ADP (200 muM), suggesting that the inosine arose from adenosine that was produced in the extracellular space by the prior release of ATP. By placing a microelectrode biosensor into the NTS under stereotaxic control we have recorded release of adenosine within this nucleus. By contrast to the brainstem surface, a fast increase in adenosine, accompanied only by a much smaller change in inosine levels, was seen following stimulation of the hypothalamic defence area. The release of adenosine following hypothalamic stimulation was mainly confined to a narrow region of the NTS some 500 mum in length around the level of the obex. Interestingly the release of adenosine was depletable: when the defence reaction was evoked at short time intervals, much less adenosine was released on the second stimulus. Our novel techniques have given unprecedented real-time measurement and localisation of adenosine release in vivo and demonstrate that adenosine is released at the right time and in sufficient quantities to contribute to the cardiovascular components of the defence reaction.