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Electrophysiology of globus pallidus neurons in vitro
Ist Teil von
Journal of neurophysiology, 1994-09, Vol.72 (3), p.1127-1139
Ort / Verlag
United States: Am Phys Soc
Erscheinungsjahr
1994
Quelle
MEDLINE
Beschreibungen/Notizen
A. Nambu and R. Llinas
Department of Physiology and Biophysics, New York University Medical Center, New York 10016.
1. We investigated the electrical properties of globus pallidus neurons
intracellularly using brain slices from adult guinea pigs. Three types of
neurons were identified according to their intrinsic electrophysiological
properties. 2. Type I neurons (59%) were silent at the resting membrane
level (-65 +/- 10 mV, mean +/- SD) and generated a burst of spikes, with
strong accommodation, to depolarizing current injection. Calcium-dependent
low-frequency (1-8 Hz) membrane oscillations were often elicited by
membrane depolarization (-53 +/- 8 mV). A low-threshold calcium conductance
and an A-current were also identified. The mean input resistance of this
neuronal type was 70 +/- 22 M omega. 3. Type II neurons (37%) fired
spontaneously at the resting membrane level (-59 +/- 9 mV). Their
repetitive firing (< or = 200 Hz) was very sensitive to the amplitude of
injected current and showed weak accommodation. Sodium-dependent
high-frequency (20-100 Hz) subthreshold membrane oscillations were often
elicited by membrane depolarization. This neuronal type demonstrated a
low-threshold calcium spike and had the highest input resistance (134 +/-
62 M omega) of the three neuron types. 4. Type III neurons (4%) did not
fire spontaneously at the resting membrane level (-73 +/- 5 mV). Their
action potentials were characterized by a long duration (2.3 +/- 0.6 ms).
Repetitive firing elicited by depolarizing current injection showed weak or
no accommodation. This neuronal type had an A-current and showed the lowest
input resistance (52 +/- 35 M omega) of the three neuron types. 5.
Stimulation of the caudoputamen evoked inhibitory postsynaptic potentials
(IPSPs) in Type I and II neurons. In Type II neurons the IPSPs were usually
followed by rebound firing. Excitatory postsynaptic potentials and
antidromic responses were also elicited in some Type I and II neurons. The
estimated conduction velocity of the striopallidal projection was < 1
m/s (Type I neurons, 0.49 +/- 0.37 m/s; Type II neurons, 0.33 +/- 0.13
m/s).