From pineal photoreception to optogenetics: functional colour opponency based on a pineal bistable opsin
Seiji Wada1,2, Emi Kawano-Yamashita3, Mitsumasa Koyanagi4,5
1Department of Biology, Graduate School of Science, Osaka Metropolitan University, Osaka, 558-8585, Japan.
Eye and Vision (London, England)
|April 19, 2026
Summary
Animals use opsins to sense light for various functions. This review explores pineal-related organ photosensitivity, focusing on pineal opsins like parapinopsin and their optogenetic potential.
Area of Science:
- * Photobiology
- * Neuroscience
- * Molecular Biology
Background:
- * Opsins are photosensitive G protein-coupled receptors crucial for light sensing in animals.
- * Vertebrate vision relies on visual opsins in retinal photoreceptor cells.
- * Pineal-related organs (
- Purpose_of_the_Study
- * To review electrophysiological evidence of photosensitivity in pineal-related organs.
- * To elucidate the molecular basis of pineal organ photosensitivity.
- * To discuss the role of parapinopsin and its optogenetic applications.
Purpose of the Study:
- * To review electrophysiological evidence of photosensitivity in pineal-related organs.
- * To elucidate the molecular basis of pineal organ photosensitivity.
- * To discuss the role of parapinopsin and its optogenetic applications.
Main Methods:
- * Electrophysiological studies of photoreception across diverse vertebrate species.
- * Genomic analysis to identify and characterize opsin gene diversity.
- * Molecular property analysis of opsins and associated signaling molecules.
Main Results:
- * Pineal-related organs exhibit photosensitivity with distinct achromatic and chromatic responses in many vertebrates.
- * Non-visual opsins, including pineal-specific parapinopsin, show remarkable diversity and distinct molecular properties.
- * Parapinopsin's unique characteristics are being explored for optogenetic applications.
Conclusions:
- * Pineal opsins play a significant molecular and physiological role in non-visual light perception.
- * The distinct properties of pineal opsins, particularly parapinopsin, offer novel avenues for optogenetics.
- * Further research into pineal opsins will advance our understanding of non-visual photoreception and its applications.
Related Concept Videos
01:22Photoreceptors and Visual Pathways
11.3K
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category,...
11.3K
01:02The Pineal Gland
8.3K
The pineal gland, a diminutive endocrine structure named for its pinecone-shaped appearance, is situated atop the third ventricle within the diencephalon region of the forebrain. This gland, composed of secretory cells known as pinealocytes arranged in compact cords and clusters around dense particles of calcium salts, plays a pivotal role in hormonal regulation.
The primary secretion of the pineal gland is the hormone melatonin, derived from serotonin. The concentration of melatonin in the...
The primary secretion of the pineal gland is the hormone melatonin, derived from serotonin. The concentration of melatonin in the...
8.3K
01:24Color Vision
2.0K
Color perception begins in the retina, the light-sensitive layer at the back of the eye. Two main theories explain how colors are seen: the trichromatic theory and the opponent-process theory. The trichromatic theory, proposed by Thomas Young in 1802 and extended by Hermann von Helmholtz in 1852, suggests that color vision is based on three types of cone receptors in the retina. These cones are sensitive to different but overlapping ranges of wavelengths corresponding to red, blue, and green.
2.0K
02:00Photoreceptors and Plant Responses to Light
29.2K
Light plays a significant role in regulating the growth and development of plants. In addition to providing energy for photosynthesis, light provides other important cues to regulate a range of developmental and physiological responses in plants.
29.2K
01:11Channel Rhodopsins
3.5K
Most organisms use photoreceptors to sense and respond to light. Examples of photoreceptors include bacteriorhodopsins and bacteriophytochromes in some bacteria, phytochromes in plants, and rhodopsins in the photoreceptor cells of the vertebral retina. The light-sensitive property of these receptors is because of the bound chromophores, such as bilin in the phytochromes and retinal in the rhodopsins.
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
3.5K
01:20Anatomy of the Eyeball
12.2K
The eye is a spherical, hollow structure composed of three tissue layers. The outer layer — the fibrous tunic, comprises the sclera — a white structure — and the cornea, which is transparent. The sclera encompasses some of the ocular surface, most of which is not visible. However, the 'white of the eye' is distinctively visible in humans compared to other species. The cornea, a clear covering at the front of the eye, enables light penetration. The eye's middle...
12.2K