MEMBRANE-PROPERTIES OF CELL-TYPES WITHIN GUINEA-PIG BASAL FOREBRAIN NUCLEI INVITRO
MEMBRANE-PROPERTIES OF CELL-TYPES WITHIN GUINEA-PIG BASAL FOREBRAIN NUCLEI INVITRO
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DOI：
10.1152/jn.1988.59.5.1590
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发表时间：
1988-05-01
影响因子：
2.5
通讯作者：
GRIFFITH, WH
中科院分区：
文献类型：
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作者：
GRIFFITH, WH
1.在离体脑片标本上，应用细胞内记录和单电极电压钳（SEVC）技术对Broca斜角带核（nDBB）和内侧隔腹侧部（MS）的神经元进行了研究。细胞类型可分为三类：细胞与一个缓慢的postspike后超极化（SAHP细胞，40%），神经元与一个快速的AHP（FAHP细胞，53%），和第三个细胞组记录不频繁（7%的细胞），发射在一个突发模式。双标记技术表明，SAHP细胞对乙酰胆碱酯酶（AChE）染色呈阳性，并且可能是胆碱能的（22）。本研究提供了一个更详细的分析，这些前脑核团内的SAHP和FAHP类型的被动和主动膜特性。2. SAHP细胞的特征在于在-65 mV时具有10-20 mV的幅度和约600 ms的持续时间的尖峰后超极化（AHP）。在-60--70 mV的电压范围内，AHP衰减为单指数函数，时间常数为170 +/- 53 ms（n = 10）。然而，许多神经元在这些膜电位表现出AHP衰减，这是一个多指数函数持续数秒。SAHP的零电位约为-90 mV，在9 mM KCl中偏移25 mV，这是钾（K+）电导的预测值。镉（Cd ~（2+））可可逆地阻断SAHP，表明SAHP是由钙（Ca ~（2+））激活的K ~+电导介导的。3. FAHP细胞显示较小幅度（5-10 mV）和持续时间（5-50 ms）的后超极化，在约-85 mV时逆转。升高细胞外K+浓度[Ko]至6 mM时，逆转更加积极13 mV。Cd 2+也降低了AHP在这些细胞表明第二个更快的Ca 2+激活的K+电导可能存在。4. SAHP和FAHP细胞具有相似的输入电阻和静息膜电位，但动作电位特征明显不同。SAHP细胞的尖峰持续时间为1.4 ms和一个突出的肩膀上的SAHP细胞动作电位的下降阶段，减少镉。与此相反，FAHP细胞的平均尖峰持续时间为0.63毫秒，不受镉2+。5.表征了两种电池类型的无源电缆特性。计算不同细胞组的树突的等效电紧张长度（L）和树突与体细胞电导比（rho）。SAHP细胞显示平均L值为0.61，平均rho为2.13。在FAHP细胞中，L和rho分别计算出相似的值0.69和2.14。（400字处截断摘要）
1. Neurons in the nucleus of the diagonal band of Broca (nDBB) and ventral portion of the medial septum (MS) were studied using intracellular recording and single-electrode voltage clamp (SEVC) techniques in an in vitro brain slice preparation. Cell types could be operationally divided into three categories: cells with a slow postspike afterhyperpolarization (SAHP cell, 40%), neurons with a fast AHP (FAHP cells, 53%), and a third cell group recorded infrequently (7% of the cells) that fired in a burst pattern. Double-labeling techniques have shown that SAHP cells stain positively for acetylcholinesterase (AChE) and are presumably cholinergic (22). The present study provides a more detailed analysis of the passive and active membrane properties of SAHP and FAHP types within these forebrain nuclei. 2. SAHP cells were characterized by a postspike afterhyperpolarization (AHP) with an amplitude of 10-20 mV and duration of approximately 600 ms at -65 mV. In the voltage range of -60--70 mV, the AHP decayed as a single exponential function with a time constant of 170 +/- 53 ms (n = 10). However, many neurons at these membrane potentials exhibited an AHP decay that was a multiple exponential function lasting for seconds. The null potential of the SAHP was approximately -90 mV and shifted by 25 mV in 9 mM KCl, a value closely predicted for a potassium (K+) conductance. The SAHP was reversibly blocked by cadmium (Cd2+), suggesting the SAHP was mediated by a calcium (Ca2+)-activated K+ conductance. 3. FAHP cells displayed afterhyperpolarizations of smaller amplitude (5-10 mV) and duration (5-50 ms) that reversed at approximately -85 mV. Elevating extracellular K+ concentration [Ko] to 6 mM shifted the reversal 13 mV more positive. Cd2+ also reduced the AHP in these cells suggesting a second faster Ca2+-activated K+ conductance may be present. 4. Both SAHP and FAHP cells had similar input resistances and resting membrane potentials but markedly different action-potential characteristics. SAHP cells had a spike duration of 1.4 ms and a prominent shoulder on the falling phase of the SAHP cell action potentials that was reduced by Cd2+. In contrast, FAHP cells had an average spike duration of 0.63 ms that was unaffected by Cd2+. 5. The passive electrical cable properties of both cell types were characterized. Equivalent electrotonic length of the dendrites (L) and the dendritic-to-somatic conductance ratio (rho) were calculated for different cell groups. SAHP cells displayed average L values of 0.61, and the average rho was 2.13. Similar values of 0.69 and 2.14 were calculated for L and rho, respectively, in FAHP cells.(ABSTRACT TRUNCATED AT 400 WORDS)