Regulation of rapid eye movement sleep in the freely moving rat: local microinjection of serotonin, norepinephrine, and adenosine into the brainstem.
OBJECTIVE
Considerable evidence suggests that rapid eye movement (REM) sleep is induced by glutamatergic activation of cholinergic cells within the pedunculopontine tegmentum (PPT). The aim of this study is to test a popular hypothesis that serotonin, norepinephrine, and adenosine act on PPT cells to regulate REM sleep. This study also tests an alternate hypothesis that serotonin may inhibit REM sleep signs by direct action on the individual REM sleep sign generators.


METHODS
Serotonin, norepinephrine, and adenosine were locally microinjected into the PPT and serotonin was microinjected into the pontine-wave (P-wave) generator (dorsal part of the locus subcoeruleus nucleus) while quantifying the effects on REM sleep and P-wave activity in freely moving rats.


METHODS
N/A.


METHODS
N/A.


METHODS
N/A.


RESULTS
Local microinjections of serotonin, norepinephrine, and adenosine into the PPT did not change REM sleep. Microinjection of serotonin into the P-wave generator suppressed P-wave activity but not REM sleep.


CONCLUSIONS
The present findings provide direct evidence that serotonin, norepinephrine, and adenosine-induced REM sleep suppression in the behaving rat are not mediated by the PPT. The results also provide direct evidence, for the first time, that serotonin suppresses P-wave activity by acting directly on the P-wave generator. These results suggest that the serotonin-induced inhibition of REM sleep in the freely moving rat is probably not mediated through the mesopontine cholinergic cell compartment but, rather, through individual REM sleep sign generators.
Datta
Subimal
S
Sleep Research Laboratory, Department of Psychiatry and Program in Behavioral Neuroscience, Boston University School of Medicine, 715 Albany Street, Boston, Massachusetts 02118, USA. SUBIMAL@BU.EDU
Mavanji
Vijayakumar
V
Patterson
Elissa H
EH
Ulloor
Jagadish
J
D000241:Adenosine / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001933:Brain Stem / Q000187:drug effects*; D002799:Cholinergic Fibers / Q000187:drug effects / Q000378:metabolism; D005133:Eye Movements / Q000187:drug effects*; D008124:Locomotion / Q000187:drug effects*; D008297:Male; D008845:Microinjections; D009638:Norepinephrine / Q000008:administration & dosage / Q000494:pharmacology*; D045042:Pedunculopontine Tegmental Nucleus / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000187:drug effects / Q000378:metabolism; D012701:Serotonin / Q000008:administration & dosage / Q000494:pharmacology*; D012895:Sleep, REM / Q000187:drug effects*
D017470:Receptors, Glutamate; D012701:Serotonin; D000241:Adenosine; D009638:Norepinephrine