JOURNAL ARTICLE
RESEARCH SUPPORT, NON-U.S. GOV'T
RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
Add like
Add dislike
Add to saved papers

5HT1B receptor agonists inhibit light-induced phase shifts of behavioral circadian rhythms and expression of the immediate-early gene c-fos in the suprachiasmatic nucleus.

Journal of Neuroscience 1996 December 16
The suprachiasmatic nucleus (SCN) is a circadian oscillator and a critical component of the mammalian circadian system. It receives afferents from the retina and the mesencephalic raphe. Retinal afferents mediate photic entrainment of the SCN, whereas the serotonergic afferents originating from the midbrain modulate photic responses in the SCN; however, the serotonin (5HT) receptor subtypes in the SCN responsible for these modulatory effects are not well characterized. In this study, we tested the hypothesis that 5HT1B receptors are located presynaptically on retinal axon terminals in the SCN and that activation of these receptors inhibits retinal input. The 5HT1B receptor agonists TFMPP and CGS 12066A, administered systemically, inhibited light-induced phase shifts of the circadian activity rhythm in a dose-dependent manner at phase delay and phase advance time points. This inhibition was not affected by previous systemic application of either the selective 5HT1A receptor antagonist (+)WAY 100135 or by the 5HT2 receptor antagonist mesulergine, whereas pretreatment with the nonselective 5HT1 antagonist methiothepin significantly attenuated the effect of TFMPP. TFMPP also produced a dose-dependent reduction in light-stimulated Fos expression in the SCN, although a small subset of cells in the dorsolateral aspect of the caudal SCN were TFMPP-insensitive. TFMPP (1 mM) infused into the SCN produced complete inhibition of light-induced phase advances. Finally, bilateral orbital enucleation reduced the density of SCN 5HT1B receptors as determined using [125I]-iodocyanopindolol to define 5HT1B binding sites. These results are consistent with the interpretation that 5HT1B receptors are localized presynaptically on retinal terminals in the SCN and that activation of these receptors by 5HT1B agonists inhibits retinohypothalamic input.

Full text links

We have located links that may give you full text access.
Can't access the paper?
Try logging in through your university/institutional subscription. For a smoother one-click institutional access experience, please use our mobile app.

For the best experience, use the Read mobile app

Mobile app image

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app

All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.

By using this service, you agree to our terms of use and privacy policy.

Your Privacy Choices Toggle icon

You can now claim free CME credits for this literature searchClaim now

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app