Light‐evoked FOS induction within the suprachiasmatic nuclei (SCN) of melanopsin knockout (Opn4^−/−) mice: A developmental study

May 12, 2006Chronobiology international

Light-induced activity in the brain's internal clock area of mice lacking a key light-sensing protein during development

AI simplified

Circadian Biology on OpenScience ↗PubMed ↗DOI ↗

Abstract

Photosensitive melanopsin-dependent retinal ganglion cells convey light information to the murine suprachiasmatic nuclei (SCN) at birth.

Photosensitive ganglion cells in mice start transmitting light signals to the SCN on the day of birth.
Developing rods and cones do not contribute to light information for the SCN during early postnatal life.
At approximately P14, rods and cones may be able to fully compensate for the absence of melanopsin-dependent signals if light exposure is prolonged.
Light-evoked expression of the FOS protein serves as a marker for assessing the competence of the retinohypothalamic tract.

AI simplified

The aims of this study were to address three related questions: (1) Do the photosensitive ganglion cells of the mouse convey light information to the suprachiasmatic nuclei (SCN) at P0? (2) Do the differentiating rods and cones contribute to light-evoked FOS induction within the murine SCN at P4? (3) How does light-evoked FOS induction within the SCN of melanopsin knockout (Opn4-/-) mice differ at P4 and P14? Our approaches took advantage of the published descriptions of murine ocular development, melanopsin knockout (Opn4-/-) mouse, and light-induced expression of FOS (the phosphoprotein product of immediate early gene c-fos) within the SCN as a marker of retinohypothalamic tract competence. Collectively, our results show that photosensitive melanopsin-dependent retinal ganglion cells provide light information to the murine SCN on the day of birth, and possibly beforehand, and that developing rods and cones fail to provide light information to the SCN during early postnatal life. On the basis of previous publications and data presented here, we suggest that at ages around P14 the rods and cones might be capable of fully compensating for the loss of melanopsin-photosensitive ganglion cells if exposure to light is of sufficiently long duration. These results are related to the broader context of recent findings and the potential role(s) of a neonatal photoreceptor.

Full Text

Full text is available at the source.

View full text ↗

Light‐evoked FOS induction within the suprachiasmatic nuclei (SCN) of melanopsin knockout (Opn4^−/−) mice: A developmental study

Abstract

Full Text

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief

Abstract

Full Text

Related papers

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief