Sleep/waking effects of a selective 5-HT1A receptor agonist given systemically as well as perfused in the dorsal raphe nucleus in rats.
Sleep/waking stages and behavior were studied following the selective 5-HT1A agonist 8-OH-DPAT given subcutaneously (s.c.) (0.010-0.375 mg/kg) as well as perfused continuously (10 microM) for 6 h into the dorsal raphe nucleus (DRN) using microdialysis. Given systemically, 8-OH-DPAT at 0.375 mg/kg s.c. induced 5-HT behavioral syndrome, increased waking to 149% and reduced slow wave sleep (SWS) to 86%, transition to 76% and rapid eye movement (REM) sleep to 73%. The effect on deep SWS (SWS-2) was biphasic, with an increase after 2 h. 8-OH-DPAT at 0.010 mg/kg did not have any vigilance effects. 8-OH-DPAT perfusion in DRN produced a fourfold increase in REM sleep compared to perfusion of artificial cerebrospinal fluid. This is consistent with the hypothesis that reduced 5-HT neurotransmission following 5-HT1A autoreceptor stimulation will disinhibit cholinergic REM-promoting mesopontine neurons and thereby lead to a REM sleep increase. The other sleep/waking stages were not significantly affected by 8-OH-DPAT perfusion in DRN.
Bjorvatn
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B
Department of Physiology, University of Bergen, Norway. bjorn.bjorvatn@pki.uib.no
Fagerland
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S
Eid
T
T
Ursin
R
R
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology*; D000818:Animals; D001143:Arousal / Q000187:drug effects / Q000502:physiology*; D017660:Autoreceptors / Q000502:physiology; D001522:Behavior, Animal / Q000187:drug effects; D003712:Dendrites / Q000737:chemistry / Q000187:drug effects / Q000502:physiology; D004569:Electroencephalography; D007279:Injections, Subcutaneous; D008297:Male; D017551:Microdialysis; D010477:Perfusion; D011903:Raphe Nuclei / Q000737:chemistry / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000502:physiology*; D044263:Receptors, Serotonin, 5-HT1; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D012890:Sleep / Q000187:drug effects / Q000502:physiology*
D017660:Autoreceptors; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D017366:Serotonin Receptor Agonists; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin