Summary
This study examined the functional role of glutamate release from intrinsically photosensitive retinal ganglion cells (ipRGCs) in driving circadian responses by conditionally deleting vGlut2 in ipRGCs. The findings help clarify the relative contributions of glutamate versus PACAP co-release in light-mediated signaling to the suprachiasmatic nucleus, with implications for understanding how lighting conditions entrain biological clocks.
Key Findings
- Conditional deletion of vGlut2 in ipRGCs reduced but did not eliminate glutamatergic EPSCs evoked by optic chiasm stimulation in the SCN, suggesting residual glutamate signaling from non-ipRGC sources or incomplete knockout.
- A functionally significant percentage of ipRGCs retained vGlut2-mediated signaling even in knock-out animals, indicating incomplete deletion and complexity in assessing the role of ipRGC glutamate alone.
- PACAP may be co-released with glutamate in the SCN from ipRGCs, suggesting that circadian light responses involve multiple neurotransmitter systems beyond glutamate alone.
Categories
The Science of Light: Investigates the role of vGlut2-mediated glutamatergic signaling from ipRGCs in circadian photoentrainment, directly relevant to photoreceptor biology and light signaling pathways.
Sleep & Circadian Health: Examines how conditional knockout of vGlut2 in ipRGCs affects circadian behavioral responses to light, providing mechanistic insight into entrainment.
Author(s)
MG Moldavan, PJ Sollars, MR Lasarev, CN Allen
Publication Year
2018
Number of Citations
5
Related Publications
The Science of Light
- Phototransduction by retinal ganglion cells that set the circadian clock
- Color appearance models
- The mammalian circadian timing system: organization and coordination of central and peripheral clocks
- Diminished pupillary light reflex at high irradiances in melanopsin-knockout mice
- Melanopsin is required for non-image-forming photic responses in blind mice
Sleep & Circadian Health
- Phototransduction by retinal ganglion cells that set the circadian clock
- The mammalian circadian timing system: organization and coordination of central and peripheral clocks
- The twoāprocess model of sleep regulation: a reappraisal
- Melanopsin is required for non-image-forming photic responses in blind mice
- Strange vision: ganglion cells as circadian photoreceptors