THE ACTIONS OF HYDROGEN-SULFIDE ON DORSAL RAPHE SEROTONERGIC NEURONS IN-VITRO
THE ACTIONS OF HYDROGEN-SULFIDE ON DORSAL RAPHE SEROTONERGIC NEURONS IN-VITRO
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DOI：
10.1152/jn.1993.70.1.81
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发表时间：
1993-07-01
影响因子：
2.5
通讯作者：
COLMERS, WF
中科院分区：
文献类型：
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作者：
KOMBIAN, SB;REIFFENSTEIN, RJ;COLMERS, WF
1.采用细胞内尖锐微电极和全细胞记录技术，在体外脑干切片制备中研究硫化氢(HS-)对中缝背侧(DR)血清素能细胞膜和突触特性的作用。2．硫化物对 DR 细胞的静息膜特性产生两种可逆、浓度依赖性效应：(1) 14% 的人对 HS- 作出反应，缓慢发生超极化或外向电流，并伴随电压钳电导增加（保持电位 = -60 mV；单相外向细胞）或 (2) 39% 的人对快速发生的去极化作出反应，对应于弱电压依赖性内向电流，显示电导在 - 115 之间几乎没有变化或没有变化。和-40 mV（单相内向细胞）。此外，29.5% 的人表现出上述两种效应，首先出现快速发生的去极化，然后出现持续的超极化。这些细胞的膜电流与单相向内和向外细胞（双相细胞）中看到的膜电流非常相似。最后，17.5% 的 DR 细胞对 HS-.3 没有可测量的突触后膜反应。当用移液管中的 2 M KCl 或 145 mM 葡萄糖酸钾记录时，在 HS- 存在下诱导的外向电流具有约 -90 mV 的反转电位，并且伴随着电导的增加，表明它是由 K+ 电导升高引起的。4。该电流对外部 Ca2+ 的去除和 Cd2+ 的阻断敏感，表明它是通过内部 [Ca2+] 的升高而激活的。它也被 apamin 或 Ba2+ 和 Cs+ 阻断，这两者都揭示了潜在的内向电流。外向电流对其他已知的电压和钙依赖性 K + 通道的多种拮抗剂的应用不敏感。使用贴片移液管升高细胞内ATP并不能阻止外向电流的激活。5． HS- 可逆地抑制在 -50 至 -40 mV 电压范围内激活的电压依赖性外向电流。该电流也被10 mM 四乙铵阻断，表明HS- 抑制了DR 细胞中的延迟整流。6．在HS-存在的情况下，不仅可以在单相内向细胞中观察到内向电流，而且可以在外向电流被选择性阻断的单相外向或双相细胞中观察到内向电流。这种内向电流对细胞外 Ca2+ 的去除或应用相对较低浓度的 Cd2+ 敏感，表明它是由 Ca2+ 携带的。这两种操作也阻断了单相外向或双相细胞中的外向电流。7．洗掉 HS- 后，观察到外向电流，该电流与电压无关，但可被 Na+/K+ ATP 酶毒毛花苷抑制剂阻断。旋花草苷不影响 HS-.8 存在时观察到的内向电流。 HS-以浓度依赖性方式可逆地抑制复合物的所有成分在 DR 血清素能细胞中引起的突触反应。 HS- 通过突触前和突触后机制发挥作用，因为它会抑制对 HS- 没有突触后膜反应的细胞中的突触电位，或者在反应细胞中没有可测量的膜效应的 HS- 浓度下抑制突触电位。9。 HS- 对 DR 神经元的膜和突触特性具有深远但特定的作用。如果类似的效应发生在脑干呼吸核中，预计呼吸节律将被扰乱，正如在体内观察到的那样。
1. The actions of hydrogen sulfide (HS-) on membrane and synaptic properties of dorsal raphe (DR) serotonergic cells were studied in the in vitro brain stem slice preparation, using intracellular sharp microelectrode and whole-cell recording techniques.2. Sulfide produced two reversible, concentration-dependent effects on resting membrane properties of DR cells: (1) 14% responded to HS- with a slow onset hyperpolarization or an outward current accompanied by an conductance increase in voltage clamp (holding potential = -60 mV; monophasic outward cell) or (2) 39% responded with a rapid-onset depolarization corresponding to a weakly voltage-dependent inward current showing little or no change in conductance between - 115 and -40 mV (monophasic inward cell). In addition, 29.5% showed both the above effects, responding first with a rapid-onset depolarization and then a sustained hyperpolarization. Such cells had membrane currents very similar to those seen in the monophasic inward and outward cells (biphasic cells). Finally, 17.5% of DR cells had no measurable postsynaptic membrane response to HS-.3. The outward current induced in the presence of HS- had a reversal potential of about -90 mV when recorded either with 2 M KCl or 145 mM potassium gluconate in the pipette and was accompanied by an increase in conductance, suggesting that it is caused by an elevated conductance to K+.4. This current was sensitive to the removal of external Ca2+ and blockade by Cd2+, suggesting that it is activated by an elevation in internal [Ca2+]. It was also blocked by apamin or Ba2+ and Cs+, both of which revealed an underlying inward current. The outward current was insensitive to the application of a large variety of antagonists to other known voltage- and calcium-dependent K + channels. Elevation of intracellular ATP using a patch pipette did not prevent the activation of the outward current.5. HS- reversibly suppressed a voltage-dependent outward current activated in the voltage range of -50 to -40 mV. This current was also blocked by 10 mM tetraethylammonium, suggesting that HS- suppresses the delayed rectifier in DR cells.6. The inward current could be observed in the presence of HS- not only in monophasic inward cells but also in monophasic outward or biphasic cells whose outward current was selectively blocked. This inward current was sensitive to the removal of extracellular Ca2+, or the the application of relatively low concentrations of Cd2+, suggesting that it is carried by Ca2+. Both these manipulations also blocked the outward current in monophasic outward or biphasic cells.7. On washout of HS-, an outward current is observed that is voltage independent but can be blocked by the inhibitor of the Na+/K+ ATPase strophanthidin. Strophanthidin did not affect the inward current seen in the presence of HS-.8. HS- reversibly inhibits, in a concentration-dependent manner, all components of the complex evoked synaptic responses in DR serotonergic cells. HS- does so via both pre- and postsynaptic mechanisms, because it inhibited synaptic potentials in cells with no postsynaptic membrane response to HS- or at HS- concentrations that had no measurable membrane effects in responding cells.9. HS- has profound but specific actions on membrane and synaptic properties of DR neurons. Should similar effects occur in brain stem respiratory nuclei, it would be expected that respiratory rhythms would be disrupted, as is observed in vivo.