GABAergic modulation of a substance P‐mediated reflex of slow time course in the isolated rat spinal cord
GABAergic modulation of a substance P‐mediated reflex of slow time course in the isolated rat spinal cord
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GABA能调节离体大鼠脊髓中P物质介导的慢时程反射
DOI：
10.1111/j.1476-5381.1987.tb08998.x
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发表时间：
1987
影响因子：
7.3
通讯作者：
M. Yanagisawa
中科院分区：
文献类型：
--
作者：
H. Akagi;M. Yanagisawa
1研究氨基丁酸(γ)等与氨基丁酸受体相互作用药物对新生大鼠脊髓慢时程反射的影响。2单次电击背根(L3~L5)可诱发相应节段对侧前根记录到的由快成分和慢成分组成的一系列刻板反射。慢成分，即对侧慢腹根电位(v.r.p.)3沐浴应用γ-氨基丁酸(5-20μm)或蝇脑(0.05-0.5μm)可使对侧慢反应v.r.p的波幅降低。而不会给华盛顿带来任何变化。从腹根记录到的电位。同侧腹根记录的单突触反射不被这些浓度的药物改变。4安定(0.1−1μm)增强背根对γ-氨基丁酸的去极化反应，显著抑制对侧慢波v.r.p。华盛顿特区也没有。安定改变了前根和背根的电位。单突触反射也不受药物的影响。5荷包牡丹碱(1μm)抑制由背根记录的GABA诱发的去极化，而明显增强对侧慢波v.r.p。6巴氯芬浓度为0.0 1~0.1μm时，对侧慢反应v.r.p。巴氯芬对对侧慢反应的抑制作用。比单突触反射更明显。7短暂应用P物质(SP)引起的前根去极化可被蝇草醇、安定和巴氯芬抑制，而荷包牡丹碱可增强这种去极化作用。8本研究结果提示，脊髓内GABA能抑制机制在某些慢脊髓反射的调节中起作用。他们还支持这样的假设，即从某些初级传入纤维释放的SP是参与对侧慢速v.r.p的神经递质。
1 The effects of γ‐aminobutyric acid (GABA) and other drugs which interact with GABA receptors were studied on a reflex of slow time course in the spinal cord preparation isolated from the neonatal rat. 2 A single shock to a dorsal root (L3‐L5) elicited a stereotyped series of reflexes, consisting of fast and slow components, recorded from the contralateral ventral root of the corresponding segment. The slow component, i.e. the contralateral slow ventral root potential (v.r.p.) had a time‐to‐peak of 2–5 s and lasted 20–30 s. 3 Bath‐application of GABA (5–20 μm) or muscimol (0.05‐0.5 μm) caused a decrease in the amplitude of the contralateral slow v.r.p. without producing any change in the d.c. potential recorded from the ventral root. The monosynaptic reflex recorded from the ipsilateral ventral root was not changed by the drugs at these concentrations. 4 Diazepam (0.1−1 μm) potentiated the depolarizing response of the dorsal root to GABA and markedly depressed the contralateral slow v.r.p. Neither the d.c. potential of the ventral root nor the dorsal root was changed by diazepam. The monosynaptic reflex was also unaffected by the drug. 5 Bicuculline (1 μm) suppressed the GABA‐induced depolarization recorded from the dorsal root whilst it markedly potentiated the contralateral slow v.r.p. 6 Baclofen at concentrations from 0.01 to 0.1 μm reduced the contralateral slow v.r.p. The inhibitory action of baclofen on the contralateral slow v.r.p. was more marked than on the monosynaptic reflex. 7 The depolarization of the ventral root induced by a brief application of substance P (SP) was depressed by muscimol, diazepam and baclofen, whereas the depolarization was potentiated by bicuculline. 8 The present results suggest that an intraspinal GABAergic inhibitory mechanism plays a role in the modulation of certain slow spinal reflexes. They also support the hypothesis that SP released from certain primary afferent fibres is a neurotransmitter involved in the contralateral slow v.r.p.