Jahromi S S, Schertzer S, Carlen P L
Toronto Hospital Research Institute, Department of Physiology, University of Toronto, Ontario, Canada.
Synapse. 1993 Jun;14(2):121-7. doi: 10.1002/syn.890140204.
The electrophysiological actions of cocaine hydrochloride (COC) on medial prefrontal cortical (mpfc) and hippocampal dentate granule (DG) neurons were investigated in rat brain slices with intracellular recording techniques. The following parameters were measured: resting membrane potential (RMP), spike threshold, spike firing adaptation, postspike train afterhyperpolarization (AHP), excitatory postsynaptic potentials (EPSPs), and inhibitory postsynaptic potentials (IPSPs). In the mpfc, COC appeared to have both inhibitory and excitatory effects. In the majority of cells examined, the EPSP amplitude was attenuated by COC (200 nM-20 microM), whereas the amplitude of the postspike train afterhyperpolarization (AHP) was reduced (an excitatory effect). In DG neurons, 1 microM COC caused a small depolarization. COC potentiated the EPSPs at 1 microM but attenuated EPSPs and IPSPs at 10-100 microM. The amplitude of antidromically evoked EPSPs was also increased by 20 microM COC. At concentrations of 10 microM and greater, COC increased spike threshold. It is concluded that COC actions on mpfc and DG neurons are both excitatory and inhibitory and that these effects may be mediated by multiple neurotransmitters/modulators.
采用细胞内记录技术，在大鼠脑片中研究了盐酸可卡因（COC）对内侧前额叶皮质（mpfc）和海马齿状颗粒（DG）神经元的电生理作用。测量了以下参数：静息膜电位（RMP）、动作电位阈值、动作电位发放适应性、动作电位发放后的超极化（AHP）、兴奋性突触后电位（EPSP）和抑制性突触后电位（IPSP）。在mpfc中，COC似乎具有抑制和兴奋两种作用。在大多数被检测的细胞中，COC（200 nM - 20 μM）使EPSP幅度衰减，而动作电位发放后的超极化（AHP）幅度减小（兴奋作用）。在DG神经元中，1 μM COC引起轻微去极化。1 μM COC增强EPSP，但在10 - 100 μM时减弱EPSP和IPSP。20 μM COC也增加了逆向诱发的EPSP幅度。在浓度为10 μM及更高时，COC提高动作电位阈值。结论是，COC对mpfc和DG神经元的作用兼具兴奋和抑制性，且这些作用可能由多种神经递质/调质介导。
