MODULATION OF SPINDLE OSCILLATIONS BY ACETYLCHOLINE, CHOLECYSTOKININ AND 1S,3R-ACPD IN THE FERRET LATERAL GENICULATE AND PERIGENICULATE NUCLEI IN-VITRO
Kh. Lee et Da. Mccormick, MODULATION OF SPINDLE OSCILLATIONS BY ACETYLCHOLINE, CHOLECYSTOKININ AND 1S,3R-ACPD IN THE FERRET LATERAL GENICULATE AND PERIGENICULATE NUCLEI IN-VITRO, Neuroscience, 77(2), 1997, pp. 335-350
The transition from sleep to waking is associated with the abolition o
f spindle waves and the appearance of tonic activity in thalamocortica
l neurons and thalamic reticular/perigeniculate GABAergic cells. We te
sted the possibility that changes such as these may arise through modu
lation of the leak potassium current, I-KL, by examining the effects o
f neurotransmitters known to modulate this current on spindle wave gen
eration in the ferret geniculate slice maintained in vitro. Local appl
ication of agents that reduce I-KL in thalamocortical neurons, includi
ng acetylcholine, DL-muscarine chloride and the glutamate metabotropic
receptor agonist 1S,3R-1-aminocyclopentane-1,3-dicarboxylic acid (1S,
3R-ACPD), to spontaneously spindling thalamocortical neurons resulted
in a 5-10 mV membrane depolarization and the abolition of spindle wave
s. Local application of 1S,3R-ACPD and cholecystokinin-8-sulfate, both
of which reduce I-KL, to GABAergic neurons of the perigeniculate nucl
eus resulted in a 10-20 mV membrane depolarization, appearance of toni
c discharge and the abolition of spindle wave generation. Local applic
ation of 1S,3R-ACPD and cholecystokinin to the perigeniculate nucleus
while recording from thalamocortical neurons resulted in the abolition
of spindle wave-associated inhibitory postsynaptic potentials and the
occurrence of a continuous barrage of smaller amplitude inhibitory po
stsynaptic potentials, presumably in response to depolarization and to
nic discharge of perigeniculate neurons. These results indicate that m
odulation of I-KL in thalamocortical neurons and perigeniculate neuron
s is capable of abolishing the generation of spindle waves in thalamic
networks. Through the modulation of I-KL, ascending and descending ac
tivating systems may control the state of the thalamus such that the t
ransition from slow wave sleep to waking is associated with the abolit
ion of slow, synchronized rhythms and the facilitation of a stale that
is conducive to sensory receptor field analysis, arousal and percepti
on. (C) 1997 IBRO.