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Circadian variation in the activity of the 5‐HT 1B autoreceptor in the region of the suprachiasmatic nucleus, measured by microdialysis in the conscious freely‐moving rat
Author(s) -
Garabette M L,
Martin K F,
Redfern P H
Publication year - 2000
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1038/sj.bjp.0703753
Subject(s) - autoreceptor , suprachiasmatic nucleus , microdialysis , circadian rhythm , endocrinology , agonist , medicine , chemistry , zeitgeber , antagonist , biology , circadian clock , central nervous system , receptor
Intracerebral microdialysis was used to examine the function of the terminal 5‐hydroxytryptamine 1B (5‐HT 1B ) autoreceptor in the region of the suprachiasmatic nuclei (SCN) of freely moving conscious rats at six time points or zeitgeber times (ZTs) across the light:dark cycle. Infusion of the 5‐HT 1A/1B agonist 5‐methoxy‐3‐(1,2,3,6‐tetrahydro‐4‐pyridyl)‐1H‐indole (RU24969) (1 μ M ) via the microdialysis probe produced a decrease in 5‐HT output when applied at ZTs 3, 6, 15 and 21 (69.8±11.9, 59±11.7, 43.9±17.2 and 45.7±17.0% respectively). At ZTs 9 and 18 RU24969 (1 μm) failed to affect the 5‐HT output significantly (28.0±11 and 32.8±24.6% decrease respectively). The profile of inhibition of 5‐HT output following infusion of RU24969 (1 μ M ) at ZT 6 was unaffected by concurrent infusion of the specific 5‐HT 1A antagonist N‐[2‐[4‐(2‐methoxyphenyl)‐1‐piperazinyl]ethyl]‐N‐(2‐pyridinyl)cyclohexanecarboxamide trihydrochloride (WAY100635) (1 μ M ) (52.48±17.5% decrease). The data demonstrate a circadian rhythm in the activity of the 5‐HT 1B autoreceptor in the region of the SCN.British Journal of Pharmacology (2000) 131 , 1569–1576; doi: 10.1038/sj.bjp.0703753