Department of Physiology, West China School of Preclinical and Forensic Medicine, Sichuan University, 3-17 Renmin South Road, Chengdu, Sichuan 610041, PR China.
Neurosci Lett. 2010 Sep 13;481(3):159-63. doi: 10.1016/j.neulet.2010.06.077. Epub 2010 Jul 3.
The present study was conducted to test our hypothesis that the large-conductance calcium-activated potassium channels (BK(Ca) channels) exist in the neurons of the pre-Bötzinger complex (PBC), a brainstem region that may generate respiratory rhythm in mammals, and play roles in central regulation of respiratory activity in neonatal rats. Immunohistochemical technique revealed that BK(Ca) channels expressed in the neurons of PBC region. Whole cell voltage clamp recordings from the neurons in the PBC showed that BK(Ca) channels could be activated by membrane depolarization and blocked by 1mM tetraethylammonium (TEA) or 10microM paxilline in the preparation of thin (about 300microm) medullary slices of neonatal rats. The rhythmic respiratory-like discharge of hypoglossal rootlets could be changed by perfusing the thick (700-900microm) medullary slices with 1mM TEA or 10microM paxilline. Both TEA and paxilline could prolong the inspiratory duration, shorten the expiratory duration and increase the respiratory frequency. The results suggest that BK(Ca) channels exist in the PBC neurons and may be involved in the central control of rhythmic respiration in the neonatal rats.
本研究旨在验证我们的假设，即大电导钙激活钾通道（BK(Ca) 通道）存在于脑桥前包钦格复合体（PBC）的神经元中，该区域可能在哺乳动物中产生呼吸节律，并在新生大鼠的中枢呼吸活动调节中发挥作用。免疫组织化学技术显示，BK(Ca) 通道在 PBC 区域的神经元中表达。全细胞膜片钳记录显示，BK(Ca) 通道可被膜去极化激活，并可被 1mM 四乙铵（TEA）或 10μM 巴氯芬阻断，在新生大鼠薄（约 300μm）延髓切片制备中。通过在厚（700-900μm）延髓切片中灌流 1mM TEA 或 10μM 巴氯芬，可改变舌下神经根的节律性呼吸样放电。TEA 和巴氯芬均可延长吸气持续时间、缩短呼气持续时间并增加呼吸频率。结果表明，BK(Ca) 通道存在于 PBC 神经元中，可能参与了新生大鼠节律性呼吸的中枢控制。
