Analysis of ionic channels of medullary respiratory neurons by whole-cell patch-clamp recordings

通过全细胞膜片钳记录分析髓质呼吸神经元的离子通道

• 批准号: 05680707
• 负责人: ONIMARU Hiroshi
• 金额: $ 1.28万
• 依托单位: Showa University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05680707/
• 关键词: respiratory center; rhythm generation; brain-stem spinal cord; Ca channels; respiratory neurons; newbron rat; medulla; Ca チャネル; Kチャネル

The purpose of the present study was to analyze properties of membrane ionic channels of mammalian medullary respiratory neurons by whole-cell patch-clamp recordings. I focused on analysis of mainly Ca channels of pre-inspiratory (Pre-I), inspiratory (Insp) and tonic-expiratory (Exp) neurons in brainstem-spinal cord preparations isolated from newborn rats. These respiratory neurons were recorded in the rostral ventrolateral medulla. After Na-channel blockade by TTX and K-channel blockade by Cs^+ and TEA^+, at least 4types of Ca-dependent membrane potential responses were revealed : 1) High-threshold Ca^<2+> spike (HTS) which has the threshold of -40 to -20mV.The HTS was observed in all types of respiratory neurons analyzed. 2) Rebound responses including low-threshold Ca^<2+> spike (LTS) ; depolarizing responses to termination of hyperpolarizing current pulses. The LTS that was induced at holding potential below -50mV,was observed frequently in Pre-I,Insp or Exp neurons that tended to … More show continuous firings (i.e.tonic pacemaker activity) in the perfusate with or without TTX.3) Low-threshold Ca^<2+> after-depolarization (L-ADP). This was observed at holding potential more negative than -45 to -50 mV and the amplitude increased with progressive membrane hyperpolarization. The L-ADP was observed in some Insp neurons. 4) Intermediate-threshold Ca^<2+> plateau potential (ITP) of which threshold ranged from -50 to -40mV.This response was characterized with slow regenerative depolarization induced by brief depolarization from resting potential level (about -50mV) and with afterdepolarization at termination of depolarizing current pulse injection. The amplitude decreased with membrane hyperpolarization. The ITP was detected in about half of Pre-I neurons and type III (receiving inhibitory synaptic input from Pre-I) Insp neurons. Pharmacological study suggested that P-and also N-type Ca channels are involved in ITP responses. The present study shows that medullary respiratory neurons in newborn rat preparations have a complex set of Ca-dependent membrane conductances, which may be relevant for the respiratory burst generation and maintenance. Less

本研究旨在用全细胞膜片钳记录技术分析哺乳动物延髓呼吸神经元膜离子通道的特性。重点分析了新生大鼠脑干-脊髓标本中吸气前(Pre-I)、吸气(InSP)和紧张性呼气(Exp)神经元的主要钙通道。这些呼吸神经元被记录在延髓头端腹外侧。TTX阻断Na通道，Cs~(++)、TEA~(++)阻断K~(2+)通道后，发现至少4种钙依赖的膜电位反应：1)高阈值钙峰(HTS)，阈值为-40~-20 mV。2)包括低阈值钙尖峰(LTS)的反弹反应；对终止超极化电流脉冲的去极化反应。在保持电位低于-50 mV时，在倾向于…的Pre-I、InSP或Exp神经元中频繁地观察到LTS(3)低阈值钙后除极(L-二磷酸腺苷)。当保持电位大于-45~-50 mV时，可观察到这一现象，且波幅随膜超极化进行性增加而增加。在部分INSP神经元中观察到L-腺苷二磷酸。4)阈值为-50~-40 mV的中阈值平台电位(ITP)，表现为从静息电位水平短暂去极化(约-50 mV)诱发的缓慢再生去极化和脉冲注入去极化终止时的后去极化。波幅随膜超极化而降低。在大约一半的前I区神经元和III型(接受前I区抑制性突触输入的)INSP神经元中检测到了ITP。药理学研究表明，P-型和N型钙通道参与了ITP的反应。本研究表明，新生大鼠延髓呼吸神经元具有一组复杂的钙依赖性膜电导，这可能与呼吸爆发的发生和维持有关。较少

项目成果

Onimaru, H.: "Application of patch-calmp method in brainstem-spinal cord preparation isolated from newborn rat. (in Japanese)" J.Physiol.Soc.Japan. 56. 369-380 (1994)

Onimaru, H.：“贴片镇静法在新生大鼠脑干脊髓制备中的应用。（日语）”J.Physiol.Soc.Japan。

Onimaru, H.: "Studies of the respiratory center using isolated brainstemspinal cord preparations." Neuroscience Research. 21. 183-190 (1995)

Onimaru, H.：“使用分离的脑干脊髓制剂对呼吸中枢进行研究。”

鬼丸 洋: "新生ラット摘出脳幹-脊髄標本におけるパッチクランプ法の適用" 日本生理学雑誌. 56. 369-380 (1994)

Hiroshi Onimaru：“膜片钳法在分离的新生大鼠脑干脊髓标本上的应用”日本生理学杂志 56. 369-380 (1994)。

Onimaru,H,.Kashiwagi,M.,Arata,A and Homma,I.: "Possible mutual excitatory couplings between inspiratory neurons in caudal ventrolateral medulla of brainstem-spinal cord preparation isolated from newborm rat." Neuroscience Letters. 150. 203-206 (1993)

Onimaru，H，.Kashiwagi，M.，Arata，A 和 Homma，I.：“从新生大鼠中分离出的脑干脊髓制剂尾侧腹外侧延髓中吸气神经元之间可能存在相互兴奋性耦合。”

Onimaru,H.,Kashiwagi,M.,Arata,A and Homma,I.: "Possible mutual excitatory couplings between inspiratory neurons in caudal ventrolateral medulla of brainstem-spinal cord preparation isolated from newborn rat." Neuroscience Letters. 150. 203-206 (1993)

Onimaru,H.、Kashiwagi,M.、Arata,A 和 Homma,I.：“从新生大鼠中分离出的脑干脊髓制剂尾侧腹外侧髓质中吸气神经元之间可能存在相互兴奋性耦合。”