| CORRELATIONS BETWEEN HIPPOCAMPAL THETA RHYTHM AND INTRACELLULAR CHARACTERISTICS OF PYRAMIDAL NEURONS |
1
2
3 |
| 해마 theta 리듬과 pyramidal neuron의 세포내 특성과의 상관관계 |
|
권호흥1, 김영진1, 남순현1, 김현정1, 이만기2, 조진화3, 최병주3 |
1경북대학교 치과대학 소아치과학교실
2경북대학교 의과대학 약리학교실
3경북대학교 치과대학 치과약리학교실 |
|
|
|
|
| Abstract |
|
Electrophysiological phenomena of pyramidal cells in the CA1 area of the dorsal hippocampus were recorded from and filled with neurobiotin in anesthetized rats. The electropharmacological properties of membrane as well as the cellular-synaptic generation of rhythmic slow activity (theta) were examined. The intracellular response characteristics of these pyramidal cells were distinctly different from responses of interneurons. Pyramidal cells had a high resting membrane potential, a low input resistance, and a large amplitude action potential. A afterhyperpolarization was followed a single action potential. Most of pyramidal cells did not display a spontaneous firing. Pyramidal cells displayed weak inward rectification and anodal break excitation. The slope of the frequency-current relation was 53.4 Hz/nA for the first interspike interval and 15.9 Hz/nA for the last intervals, suggesting the presence of spike frequency adaptation. Neurobiotin-filled neurons showed pyramidal morphology. Cells were generally bipolar dendritc processes ramifying in stratum lacunosum-moleculare, radiatum, and oriens. Commissural stimulation discharged pyramidal cells, followed by excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs). The frequency of theta-related membrane potential oscillation was voltage-independent in pyramidal neurons. At strong depolarization levels (less than 30 mV) pyramidal cells emitted sodium spike oscillation, phase-locked to theta. The observations provide direct evidence that theta-related rhythmic hyperpolarization of principal cells is brought by the rhythmically discharging interneurons. Furthermore, the findings in which interneurons were also paced by rhythmic inhibitory postsynaptic potentials during theta suggest that they were periodically hyperpolarized by their GABAergic septal afferents. |
| Key Words:
intracelluar recording, pyramidal cell, theta rhythm, neurobiotin |
|
PDF Links
Download Citation
