Mode of Action of Pineal Nerve Fibers in Frogs

Dodt, E.; Heerd, E.

doi:10.1152/jn.1962.25.3.405

Cited by 205 publications

(47 citation statements)

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“…Using intracellular recording techniques, we found that the erythrophore photoresponses were associated with changes in membrane potential. Our findings suggest that tilapia cone photopigments are involved in erythrophore photoresponses and form a chromatically specific antagonistic photosensitive mechanism that is similar to those found in other non-visual photoreceptors like the reptile parietal eye and the amphibian frontal and pineal organs (Dodt and Heerd, 1962;Dodt and Morita, 1964;Dodt and Scherer, 1968).…”

Section: Introductionsupporting

confidence: 62%

“…One type is achromatic (not colour coded), and is involved in the inhibitory action of light regardless of wavelengths (Hartwig and Baumann, 1974;Meissl and Ueck, 1980;Meissl and Ekström, 1988). The other shows a chromatic response where an inhibitory component is sensitive to short wavelengths and an excitatory component is sensitive to middle/long wavelengths (Dodt and Heerd, 1962;Uchida and Morita, 1990;Solessio and Engbretson, 1993). For example, the parietal (third) eye of lizards displays chromatically dependent responses consisting of short-wavelength-sensitive hyperpolarisation and green-sensitive depolarisation (Solessio and Engbretson, 1993).…”

Section: Discussionmentioning

confidence: 99%

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Functional characterisation of the chromatically antagonistic photosensitive mechanism of erythrophores in the tilapiaOreochromis niloticus

Chen

Xiao

Troje

et al. 2015

Journal of Experimental Biology

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Non-visual photoreceptors with diverse photopigments allow organisms to adapt to changing light conditions. Whereas visual photoreceptors are involved in image formation, non-visual photoreceptors mainly undertake various non-image-forming tasks. They form specialised photosensory systems that measure the quality and quantity of light and enable appropriate behavioural and physiological responses. Chromatophores are dermal non-visual photoreceptors directly exposed to light and they not only receive ambient photic input but also respond to it. These specialised photosensitive pigment cells enable animals to adjust body coloration to fit environments, and play an important role in mate choice, camouflage and ultraviolet (UV) protection. However, the signalling pathway underlying chromatophore photoresponses and the physiological importance of chromatophore colour change remain under-investigated. Here, we characterised the intrinsic photosensitive system of red chromatophores (erythrophores) in tilapia. Like some nonvisual photoreceptors, tilapia erythrophores showed wavelengthdependent photoresponses in two spectral regions: aggregations of inner pigment granules under UV and short-wavelengths and dispersions under middle-and long-wavelengths. The action spectra curve suggested that two primary photopigments exert opposite effects on these lightdriven processes: SWS1 (short-wavelength sensitive 1) for aggregations and RH2b (rhodopsin-like) for dispersions. Both western blot and immunohistochemistry showed SWS1 expression in integumentary tissues and erythrophores. The membrane potential of erythrophores depolarised under UV illumination, suggesting that changes in membrane potential are required for photoresponses. These results suggest that SWS1 and RH2b play key roles in mediating intrinsic erythrophore photoresponses in different spectral ranges and this chromatically dependent antagonistic photosensitive mechanism may provide an advantage to detect subtle environmental photic change.

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Section: Introductionsupporting

confidence: 62%

Section: Discussionmentioning

confidence: 99%

Functional characterisation of the chromatically antagonistic photosensitive mechanism of erythrophores in the tilapiaOreochromis niloticus

Chen

Xiao

Troje

et al. 2015

Journal of Experimental Biology

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“…The pineal organ is widely accepted as a synthesizer and secretor of melatonin (Falcon et al, 1989;Gern and Greenhouse, 1988;Samejima et al, 2000;Samejima et al, 1997;Underwood, 1985). In addition to the secretory response, the pineal photoreceptor transduces a light signal to an electrical response, which is transmitted to the brain via pineal ganglion cells (Dodt, 1973;Dodt and Heerd, 1962;Morita, 1969). Physiologically, the pineal organ has two types of ganglion cell, chromatic and achromatic.…”

Section: Introductionmentioning

confidence: 99%

Immunohistochemical characterization of a parapinopsin-containing photoreceptor cell involved in the ultraviolet/green discrimination in the pineal organ of the river lamprey Lethenteron japonicum

Kawano‐Yamashita

Terakita

Koyanagi

et al. 2007

Journal of Experimental Biology

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SUMMARY In the pineal organ, two types of ganglion cell exhibit antagonistic chromatic responses to UV and green light, and achromatic responses to visible light. In this study, we histologically characterized UV-sensitive photoreceptor cells that contain a unique non-visual UV pigment, lamprey parapinopsin, in order to elucidate the neural network that is associated with antagonistic chromatic responses. These characteristics were compared with those of lamprey rhodopsin-containing cells, most of which are involved in achromatic responses. RT-PCR analysis revealed that lamprey parapinopsin was expressed in the pineal organ but not in the retina, unlike lamprey rhodopsin,which was expressed in both. Lamprey parapinopsin and lamprey rhodopsin were immunohistochemically localized in the dorsal and ventral regions of the pineal organ, respectively. The two pigments were localized in distinct photoreceptor cells throughout the pineal organ, namely the dorsal and ventral regions as well as the peripheral region, which corresponds to the dorso-ventral border region. The ratio of the number of lamprey parapinopsin-containing cells to lamprey rhodopsin-containing cells around the peripheral region was higher than in the central region. Electron-microscopic analysis revealed that lamprey parapinopsin-containing dorsal cells have outer segments and synaptic ribbons similar to those of ventral photoreceptor cells. However, unlike lamprey rhodopsin-containing cells, lamprey parapinopsin-containing cells connected with each other in a wide area of dorsal and peripheral portions and made direct contact with ganglion cells,mainly in the peripheral portion. These results suggest that UV light information captured by lamprey parapinopsin-containing photoreceptor cells is converged and directly transmitted to chromatic-type ganglion cells in the peripheral region to generate antagonistic chromatic responses.

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“…It is widely accepted that the photoreception of the pineal is involved in various lightregulated physiological events such as the biological clock. Although extraocular photoreceptors typically exhibit maximum sensitivities in blue to green light, several electrophysiological studies have demonstrated UV reception in the pineal complex of a variety of lower vertebrates, such as lamprey (3), trout (4), pike (5), and frogs (6,7). In these animals, UV light suppresses the neuronal firing of a specific kind of ganglion cell in the pineal complex, whereas visible light stimulates the neuronal activity, which is called chromatic responses.…”

mentioning

confidence: 99%

Bistable UV pigment in the lamprey pineal

Koyanagi

Kawano

Kinugawa

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

139

198

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Lower vertebrates can detect UV light with the pineal complex independently of eyes. Electrophysiological studies, together with chromophore extraction analysis, have suggested that the underlying pigment in the lamprey pineal exhibits a bistable nature, that is, reversible photoreaction by UV and visible light, which is never achieved by known UV pigments. Here we addressed the molecular identification of the pineal UV receptor. Our results showed that the long-hypothesized pigment is a lamprey homologue of parapinopsin, which exhibits an absorption maximum at 370 nm, in the UV region. UV light causes cis-trans isomerization of its retinal 2 chromophore, forming a stable photoproduct having an absorption maximum at 515 nm, in the green region. The photoproduct reverts to the original pigment upon visible light absorption, showing photoregeneration of the pigment. In situ hybridization showed that parapinopsin is selectively expressed in the cells located in the dorsal region of the pineal organ. We successfully obtained the hyperpolarizing responses with a maximum sensitivity of Ϸ380 nm from the photoreceptor cells at the dorsal region, in which the outer segment was clearly stained with anti-parapinopsin antibody. These results demonstrated that parapinopsin is the pineal UV pigment having photointerconvertible two stable states. The bistable nature of the parapinopsin can account for the photorecovery of the pineal UV sensitivity by background green light in the lamprey. Furthermore, we isolated the parapinopsin homologues from fish and frog pineal complexes that exhibit UV sensitivity, suggesting that parapinopsin is a common molecular basis for pineal UV reception in the vertebrate.

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Mode of Action of Pineal Nerve Fibers in Frogs

Cited by 205 publications

References 0 publications

Functional characterisation of the chromatically antagonistic photosensitive mechanism of erythrophores in the tilapiaOreochromis niloticus

Functional characterisation of the chromatically antagonistic photosensitive mechanism of erythrophores in the tilapiaOreochromis niloticus

Immunohistochemical characterization of a parapinopsin-containing photoreceptor cell involved in the ultraviolet/green discrimination in the pineal organ of the river lamprey Lethenteron japonicum

Bistable UV pigment in the lamprey pineal

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