Inhibitory synaptic potentials recorded from mammalian neurones prolonged by blockade of noradrenaline uptake.
Inhibitory synaptic potentials recorded from mammalian neurones prolonged by blockade of noradrenaline uptake.
复制标题
哺乳动物神经元记录的抑制性突触电位通过阻断去甲肾上腺素的摄取而延长。
DOI：
10.1113/jphysiol.1987.sp016357
复制
发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Williams,JT
中科院分区：
文献类型：
--
作者：
Surprenant,A;Williams,JT
1. 对大鼠蓝斑核和豚鼠粘膜下神经丛神经元进行了细胞内膜电位和膜电流的记录。这些神经元表现出抑制性突触后电位（ips.p.s），这是由去甲肾上腺素作用于α 2 -肾上腺素受体导致钾电导增加引起的。2. 可卡因（0.2 - 30微米）可可逆地增加蓝斑神经元和粘膜下丛神经元的突触后电流或抑制性突触后电流的持续时间，分别增加约750%和350%。引起突触电流半最大延长的可卡因浓度在蓝斑区为3微米，在粘液下丛为0.5微米。这种延长完全是由于突触反应的衰减速度较慢。3. 可卡因（10微米）在蓝斑神经元中产生维持的超极化（2 ~ 10毫伏）或向外电流（20 ~ 120毫伏）；在粘液下神经丛神经元中，可卡因增加了自发性ipps的振幅和持续时间。过量的去甲肾上腺素产生的向外电流被可卡因增加，在10 - 30微米可卡因时观察到最大的影响。向外电流或膜超极化与去甲肾上腺素浓度之间的最大左移在蓝斑神经元中为18 - 100倍，在粘液下丛神经元中为4倍。导致过量去甲肾上腺素敏感性增加一半的可卡因浓度在两种组织中相似，蓝斑为4 μ m，粘膜下丛为2 μ m。5. 这些结果表明，神经元对肾上腺素能神经释放的去甲肾上腺素的摄取在决定去甲肾上腺素介导的突触电位的时间过程中起重要作用。
1. Intracellular recordings of membrane potential and membrane current were made from neurones of the rat nucleus locus coeruleus and the guinea‐pig submucous plexus. These neurones exhibit inhibitory post‐synaptic potentials (i.p.s.p.s) which result from noradrenaline acting on alpha 2‐adrenoceptors to cause an increase in potassium conductance. 2. Cocaine (0.2‐30 microM) reversibly increased the duration of the i.p.s.p. or inhibitory post‐synaptic current (i.p.s.c.) in locus coeruleus neurones and submucous plexus neurones by approximately 750% and 350% respectively. The concentrations of cocaine causing half‐maximal prolongation of the synaptic current were 3 microM in locus coeruleus and 0.5 microM in submucous plexus. The prolongation was due entirely to a slower rate of decay of the synaptic response. 3. Cocaine (10 microM) produced a maintained hyperpolarization (2‐10 mV) or outward current (20‐120 pA) in locus coeruleus neurones; in submucous plexus neurones cocaine increased the amplitude and duration of spontaneous i.p.s.p.s. 4. Outward currents produced by superfusion with noradrenaline were increased by cocaine with maximum effects being observed at 10‐30 microM‐cocaine. The maximum leftward shift in the relation between outward current or membrane hyperpolarization and noradrenaline concentration was 18‐ to 100‐fold in locus coeruleus neurones and 4‐fold in submucous plexus neurones. The concentrations of cocaine which caused a half‐maximal increase in sensitivity to superfused noradrenaline were similar in both tissues, being 4 microM in locus coeruleus and 2 microM in submucous plexus. 5. These results show that neuronal uptake of noradrenaline released from adrenergic nerves plays a significant role in determining the time course of synaptic potentials mediated by noradrenaline.