Qi Ying, Qian Zhi-Bin, Wu Zhong-Hai
Department of Physiology, Southern Medical University, Guangzhou 510515, China.
Sheng Li Xue Bao. 2008 Jun 25;60(3):397-402.
The present study was carried out to determine the role of histamine H(1) and H(2) receptors in the generation of basic respiratory rhythm. Neonatal (aged 0-3 d) Sprague-Dawley rats of either sex were used. The medulla oblongata slice containing the medial region of the nucleus retrofacialis (mNRF) and the hypoglossal nerve rootlets was prepared and the surgical procedure was performed in the modified Kreb's solution (MKS) with continuous carbogen (95% O(2) and 5% CO(2)), and ended in 3 min. Respiratory rhythmical discharge activity (RRDA) of the rootlets of hypoglossal nerve was recorded by suction electrode. Thirty medulla oblongata slice preparations were divided into 5 groups. In groups I, II and III, histamine (5 μmol/L), H(1) receptor specific antagonist pyrilamine (10 μmol/L) and H(2) receptor specific antagonist cimetidine (5 μmol/L) was added into the perfusion solution for 15 min separately. In group IV, after application of histamine for 15 min, additional pyrilamine was added into the perfusion for another 15 min. In group V, after application of histamine for 15 min, additional cimetidine was added into the perfusion for another 15 min. The discharges of the roots of hypoglossal nerve were recorded. Signals were amplified and band-pass filtered (100-3.3 kHz). Data were sampled (1-10 kHz) and stored in the computer via BL-420 biological signal processing system. Our results showed that histamine significantly decreased the respiratory cycle (RC) and expiratory time (TE), but changes of integral amplitude (IA) and inspiratory time (TI) were not statistically significant. Pyrilamine induced significant increases in RC and TE, but changes of TI and IA were not statistically significant. Cimetidine had no effects on RC, TE, TI and IA of RRDA. The effect of histamine on the respiratory rhythm was reversed by additional application of pyrilamine but not cimetidine. Taken together, with the results mentioned above, histamine H(1) receptors but not H(2) receptors may play an important role in the modulation of RRDA in the medulla oblongata slice preparation of neonatal rats.
本研究旨在确定组胺H(1)和H(2)受体在基本呼吸节律产生中的作用。使用新生（0 - 3日龄）的Sprague-Dawley大鼠，雌雄不限。制备包含面神经后核内侧区域（mNRF）和舌下神经根丝的延髓切片，并在含有持续卡波金（95% O(2)和5% CO(2)）的改良克雷布斯溶液（MKS）中进行手术操作，手术在3分钟内完成。通过吸引电极记录舌下神经根丝的呼吸节律性放电活动（RRDA）。30个延髓切片标本分为5组。在第I、II和III组中，分别将组胺（5 μmol/L）、H(1)受体特异性拮抗剂吡苄明（10 μmol/L）和H(2)受体特异性拮抗剂西咪替丁（5 μmol/L）加入灌注液中15分钟。在第IV组中，在应用组胺15分钟后，再向灌注液中加入吡苄明并持续15分钟。在第V组中，在应用组胺15分钟后，再向灌注液中加入西咪替丁并持续15分钟。记录舌下神经根的放电情况。信号经放大和带通滤波（100 - 3.3 kHz）。数据进行采样（1 - 10 kHz）并通过BL - 420生物信号处理系统存储在计算机中。我们的结果表明，组胺显著缩短呼吸周期（RC）和呼气时间（TE），但积分幅度（IA）和吸气时间（TI）的变化无统计学意义。吡苄明使RC和TE显著延长，但TI和IA的变化无统计学意义。西咪替丁对RRDA的RC、TE、TI和IA无影响。额外应用吡苄明可逆转组胺对呼吸节律的作用，而西咪替丁则不能。综上所述，结合上述结果，组胺H(1)受体而非H(2)受体可能在新生大鼠延髓切片标本中RRDA的调节中起重要作用。
