Central Nervous System Research Group, Department of Physiology, Université de Montréal, Montréal, QC, Canada H3T 1J4.
Proc Natl Acad Sci U S A. 2012 Jan 10;109(2):E84-92. doi: 10.1073/pnas.1113002109. Epub 2011 Dec 12.
When animals move, respiration increases to adapt for increased energy demands; the underlying mechanisms are still not understood. We investigated the neural substrates underlying the respiratory changes in relation to movement in lampreys. We showed that respiration increases following stimulation of the mesencephalic locomotor region (MLR) in an in vitro isolated preparation, an effect that persists in the absence of the spinal cord and caudal brainstem. By using electrophysiological and anatomical techniques, including whole-cell patch recordings, we identified a subset of neurons located in the dorsal MLR that send direct inputs to neurons in the respiratory generator. In semi-intact preparations, blockade of this region with 6-cyano-7-nitroquinoxaline-2,3-dione and (2R)-amino-5-phosphonovaleric acid greatly reduced the respiratory increases without affecting the locomotor movements. These results show that neurons in the respiratory generator receive direct glutamatergic connections from the MLR and that a subpopulation of MLR neurons plays a key role in the respiratory changes linked to movement.
当动物运动时，呼吸会增加以适应能量需求的增加；但其潜在机制仍未被理解。我们研究了七鳃鳗中与运动相关的呼吸变化的神经基础。我们表明，在离体分离的标本中刺激中脑运动区（MLR）后，呼吸会增加，而这种效应在没有脊髓和延髓尾部的情况下仍然存在。通过使用电生理和解剖技术，包括全细胞膜片钳记录，我们鉴定出位于背侧 MLR 中的一组神经元，它们直接向呼吸发生器中的神经元发送输入。在半完整标本中，用 6-氰基-7-硝基喹喔啉-2,3-二酮和（2R）-氨基-5-膦戊酸阻断该区域会大大减少呼吸增加，而不影响运动。这些结果表明，呼吸发生器中的神经元接收来自 MLR 的直接谷氨酸能连接，并且 MLR 中的一个亚群神经元在与运动相关的呼吸变化中起着关键作用。
