The Parietal Eye (Pineal and Parietal Organs) of Lower Vertebrates

Dodt, E.

doi:10.1007/978-3-642-65495-4_4

Cited by 77 publications

(46 citation statements)

References 60 publications

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“…The large majority of these studies were extracellular recordings from postsynaptic pineal neurons, and they thus give only an indirect assessment of the presence of different types of photoreceptors. Still, there is strong evidence of the presence of more than one photopigment in the pineal complex of several species (for reviews see Dodt 1973;Meissl & Dodt 1981 identification characteristic, possibly implicating the spectral sensitivity of the photoreceptor cell. The identification of opsins in the pineal organ was long dependent on the use of antibodies against retinal opsins from mammals or birds.…”

Section: Are There Really Many Types Of Pineal Photoreceptors?mentioning

confidence: 99%

“…(…the sensory cells become, through the loss of their receptoral parts, mammalian pineal cells.). The great impact of the early ultrastructural studies was enforced by the close correlation with comparative neurophysiological studies (reviewed by Dodt 1973;Meissl & Dodt 1981) and studies of indoleamine metabolism (e.g. Collin 1968a; Quay et al 1968a;Wartenberg & Baumgarten 1969;Owman et al 1970;Collin & Meiniel 1973a,b;Ueck 1973Ueck , 1974.…”

Section: Introductionmentioning

confidence: 99%

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Evolution of photosensory pineal organs in new light: the fate of neuroendocrine photoreceptors

Ekström

Meissl

2003

Phil. Trans. R. Soc. Lond. B

123

122

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Pineal evolution is envisaged as a gradual transformation of pinealocytes (a gradual regression of pinealocyte sensory capacity within a particular cell line), the so-called sensory cell line of the pineal organ. In most non-mammals the pineal organ is a directly photosensory organ, while the pineal organ of mammals (epiphysis cerebri) is a non-sensory neuroendocrine organ under photoperiod control. The phylogenetic transformation of the pineal organ is reflected in the morphology and physiology of the main parenchymal cell type, the pinealocyte. In anamniotes, pinealocytes with retinal cone photoreceptor-like characteristics predominate, whereas in sauropsids so-called rudimentary photoreceptors predominate. These have welldeveloped secretory characteristics, and have been interpreted as intermediaries between the anamniote pineal photoreceptors and the mammalian non-sensory pinealocytes. We have re-examined the original studies on which the gradual transformation hypothesis of pineal evolution is based, and found that the evidence for this model of pineal evolution is ambiguous. In the light of recent advances in the understanding of neural development mechanisms, we propose a new hypothesis of pineal evolution, in which the old notion 'gradual regression within the sensory cell line' should be replaced with 'changes in fate restriction within the neural lineage of the pineal field'.

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Section: Are There Really Many Types Of Pineal Photoreceptors?mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Evolution of photosensory pineal organs in new light: the fate of neuroendocrine photoreceptors

Ekström

Meissl

2003

Phil. Trans. R. Soc. Lond. B

123

122

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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%

“…Several electrophysiological studies have demonstrated that the neural activity of chromatic-type ganglion cells is inhibited by UV/short wavelength light and excited by green/long wavelength light, whereas that of achromatic-type ganglion cells is inhibited by visible light in the pineal organ of the lamprey (Morita and Dodt, 1973), teleost (Morita, 1966) and frog (Dodt and Heerd, 1962). Therefore, chromatic-type ganglion cells detect the ratio of short wavelength light to long wavelength light in environmental light (Dodt, 1973), suggesting that the pineal organ is involved in the wavelength discrimination of the photic component in incident light.…”

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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“…The direct photosensitivity of pineal organ has been confirmed in many species of poikilotherm animals (DoDT, 1973). In the lamprey the photoreceptive pineal is situated on the dorsal surface of the diencephalon and beneath a translucent region of integument and connective tissue which is called the pineal window.…”

Section: Pineal Photoreceptorsmentioning

confidence: 95%