The Journal of Neuroscience, May 1, 2000, 20(9):3319-3327
Cuneiform Neurons Activated during Cholinergically Induced Active
Sleep in the Cat
Inés
Pose2,
Sharon
Sampogna1,
Michael
H.
Chase1, and
Francisco R.
Morales1, 2
1 Department of Physiology and the Brain Research
Institute, University of California at Los Angeles, Los Angeles,
California 90095, and 2 Departamento de Fisiología,
Facultad de Medicina, Montevideo 11800, Uruguay
In the present study, we report that the cuneiform (Cun) nucleus, a
brainstem structure that before now has not been implicated in sleep
processes, exhibits a large number of neurons that express c-fos during carbachol-induced active sleep
(AS-carbachol). Compared with control (awake) cats, during
AS-carbachol, there was a 671% increase in the number of neurons that
expressed c-fos in this structure. Within the Cun
nucleus, three immunocytochemically distinct populations of neurons
were observed. One group consisted of GABAergic neurons, which
predominantly did not express c-fos during AS-carbachol.
Two other different populations expressed c-fos during
this state. One of the Fos-positive (Fos+)
populations consisted of a distinct group of nitric oxide synthase (NOS)-NADPH-diaphorase (NADPH-d)-containing neurons; the
neurotransmitter of the other Fos+ population
remains unknown. The Cun nucleus did not contain cholinergic, catecholaminergic, serotonergic, or glycinergic neurons. On the basis
of neuronal activation during AS-carbachol, as indicated by
c-fos expression, we suggest that the Cun nucleus is
involved, in an as yet unknown manner, in the physiological expression
of active sleep. The finding of a population of NOS-NADPH-d containing neurons, which were activated during AS-carbachol, suggests that nitrergic modulation of their target cell groups is likely to play a
role in active sleep-related physiological processes.
Key words:
cuneiform nucleus; REM sleep; brainstem; immunohistochemistry; Fos; nitric oxide
Copyright © 2000 Society for Neuroscience 0270-6474/00/2093319-09$05.00/0