Study type: In vitro · Status: Evidence verified by machine against declared source
Roles of Neuropeptides, VIP and AVP, in the Mammalian Central Circadian Clock.
Frontiers in Neuroscience · 2021
Study scale: However, the results showed that the cells exhibiting circadian rhythms under TTX treatment were not the same between the two trials.
Abstract only: Open source record
Product or molecular entity relationships
- VIP: Exact entity relationship. Legacy citation custody associates this source with the catalog record; no product-relevance conclusion is implied.
Public plain-language summary
The published text is limited to the declared source and preserves reported uncertainty. It does not establish efficacy, safety, suitability, or evidence strength.
Research question
Several neuropeptides such as arginine vasopressin (AVP) and vasoactive intestinal polypeptide (VIP) are expressed in the SCN, where these neuropeptides function as synchronizers and are important for entrainment to environmental light and for determining the circadian period.
Study design
In dispersed cell culture, individual SCN cells show autonomous circadian rhythms, but not all cells maintain rhythmicity.
Participants or experimental system
Individual SCN cells exhibit intrinsic oscillations, and their circadian period and robustness are different cell by cell in the absence of cellular coupling, indicating that cellular coupling is important for coherent circadian rhythms in the SCN.
Study scale
However, the results showed that the cells exhibiting circadian rhythms under TTX treatment were not the same between the two trials.
Intervention or exposure
They also treated SCN slices with tetrodotoxin (TTX) for 6 days twice at 6-day intervals and examined PER2:LUC rhythmicity.
Comparator
However, it took longer to restore the circadian rhythms of VPAC2 KO SCN as compared to VIP KO SCN.
Outcomes examined
Webb et al. (2009) measured PER2:LUC bioluminescence from dispersed SCN cells and performed post hoc immunostaining to identify which neurons (i.e., those expressing AVP or VIP) are responsible for rhythm generation.
Key findings
These results suggest that cellular networks are crucial for coherent circadian rhythms in the SCN.
Limitations and uncertainty
The role of VIP neurons in circadian behavioral rhythms is still controversial and remains to be studied.
Product relevance and evidence boundary
This record is a published study, held here with its citation and review status. It is not a statement that any catalog item is effective, safe, or suitable for any use, and nothing in it is a dose or a protocol.
Evidence verified by machine against declared source. Verification is limited to the declared source and review scope. It does not mean independent replication or establish efficacy, safety, or suitability.