Ultraviolet sensitivity in the torus semicircularis of juvenile rainbow trout (Oncorhynchus mykiss) (original) (raw)
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Vision Research, 2010
The UVS cone mechanism is known to light adapt at low intensities in comparison to other cones. We were interested in whether this property was related to higher sensitivity in UVS cones or to network adjustments in sensitivity. We investigated spectral sensitivity of 107 individual cone photoreceptors in rainbow trout (Oncorhynchus mykiss) using a whole-cell voltage clamp technique. Mean time-to-peak response was 339 ± 90 ms and flash sensitivity for a 100 ms flash was 4.37 Â 10 À3 ± 2.50 Â 10 À3 pA photons À1 lm 2 , with no significant differences between the UVS, SWS, MWS and LWS cone classes. The spectral sensitivity of the UVS, SWS and LWS cones conformed to the expression of SWS1, SWS2 and LWS opsin genes. The spectral sensitivity of MWS cones, however, showed clear evidence of co-expression of RH2a and RH2b opsin pigments. The fish used in this study bridged the ontogenetic stage where the MWS cones shift their expression from RH2b to RH2a.
Spectral characteristics of visual pigments in rainbow trout (Oncorhynchus mykiss)
Vision Research, 1994
We investigated retina preparations of young rainbow trout (Oncorliryncirus mykiss) with body wt 5-40 g. Rods, single and double cones were measured in side-on orientation by microspectrophotometry, identifying five spectrally distinct visual pigments (or photoreceptors containing mixtures of visual pigment). The mean wavelength of peak absorbance (I.=,) of the a-bands were 345 and 434 nm in single cones, 531 and 576 nm in double cones, and 521 nm in the rods. The half-band width (HBW) of the main absorption bands were broader than expected of retinal-(vitamin A,-) based visual pigments, and thus, they were indicative of a mixed chromophore pool derived from both the vitamin A, and A, forms. One consequence of the utilization of mixed chromophores is the broadening of the a-band auction in each pigment type. And yet, we obtained exceptionally narrow HBW for the W-type pigment, when compared with HBW values expected on the basis of the linear trend seen in visual pigments absorbing in the visible spectrum. We conclude that the UV pigment in rainbow trout has an unusually narrow HBW. Nevertheless, this species is not exceptional in this regard, for the UV-absorbing visual pigments in other vertebrate species also have narrow HBW.
Vision Research, 1973
RETINAL extracts from many teleost fishes yield two visual pigments, one based on retinol (Al-based) and the other on 3dehy~oretinol (AZ-based) (DARTNALL and LYTHGOE, 1965;. The proportion of these two pigments has been found to vary with several factors, such as the salinity of the environment (e.g. WALD, 1957; BEATER, 1966), the administration of thyroid hormone (BEATT~, 1969 ;, the age of the fish 197Oa), the part of the retina from which the sample is taken (MUEITZ and NORTHMORE, 1971; REUTER, WHH-E and WALD, 1971;, and the lighting conditions (DARTHALL, LANDER and MUNZ, 1961; BRIDGES, 1965; BEATER, 1969). These various findings have led to considerable speculation on the visual role of these two pigment types.
Activity of long-wavelength cones under scotopic conditions in the cyprinid fish Danio aequipinnatus
Journal of Comparative Physiology A: Sensory, Neural, and Behavioral Physiology, 1997
In carp (Cyprinus) and gold®sh (Carassius), long-wavelength cones are reported to be active under scotopic conditions. Using the electroretinogram (ERG), we tested another cyprinid ®sh, Danio aequipinnatus, which contains A 1 -based visual pigments and for which we had previously measured the spectral sensitivities of individual cones. Dark adaptation curves show a rod/cone break at about 45 min. When thoroughly dark-adapted, the spectral sensitivity function is broader than can be accounted for by self-screening of rhodopsin, but it can be modeled by an additive combination of rods and the 560-nm cones. Dim, red background light causes adaptation of rods and a broadening of the spectral sensitivity function, which can be simulated by increasing the proportion of cones in the model. Brighter red backgrounds adapt the 560-nm cones. Because of the eect of red adapting lights, the ERG evidence for the participation of longwavelength cones close to visual threshold appears to be dierent in Danio than in the gold®sh Carassius.
Wavelength discrimination of the goldfish in the ultraviolet spectral range
Vision Research, 1994
Wavelength discrimination ability of the gold&& was measured with a behavioural trahdng technique in the UV spectral range. First, spectral sensitivity was determined for the two iIsh to adjust the monochromatic lights (between 334 and 450 mn) to equal subjective brightness. The results of the wavelength discrimination experiment show that, independent of which wavelength the fish were trained on, the relative choice frequency reached values above 70% only at wavelengths longer than 410 nm. Wavelength discrimination between 344 and 404nm was not possible. Accordingly, the Al function increases steeply between 400 and 380 nm, with values between about 12 and 90 nm, respectively. Model computations indicate that the ArZ function cannot be explained on the basis of the cone sensitivity spectra. Instead, inhibitory interactions have to be assumed which suppress the short wavelength flanks of the short-, mid-, and long-wavelength sensitive cone types in the W range.
Optic nerve response and retinal structure in rainbow trout of different sizes
Vision Research, 1993
This study presents evidence of ultraviolet (UV) sensitive, ON center ganglion cells in the fish retina. We determined the spectral sensitivity of ON and OFF responses from the optic nerve mass potential in small (18.0-28.5 g) and large (59.5435 g) rainbow trout, with special reference to UV sensitivity. Under a mid + long-wavelength adapting background, the ON response of small fish revealed the presence of a UV cone mechanism (,I,,,,, 390 nm) which was absent in large specimens. Under similar background conditions, the OFF response of both small and large fish showed one sensitivity peak, dominated by inputs from an M-cone mechanism. An almost complete absence of the accessory comer cones from the retinal mosaic was correlated with the loss of UV sensitivity.
Journal of Comparative Physiology A: Sensory, Neural, and Behavioral Physiology, 1998
Two families of ®shes, the Cyprinidae and Salmonidae, exhibit ultraviolet sensitivity and polarization sensitivity (i.e., dierential sensitivity to the orientation of the electric ®eld of polarized light). Both of these families possess a square arrangement of double cones and/or their dividing partitions in the centrotemporal retina, an area where polarization sensitivity has been tested for and found. To correlate the presence of an ordered cone mosaic in the centro-temporal retina with polarization sensitivity in ultraviolet-sensitive ®shes, we examined the visual system of the common white sucker (Catostomus commersoni) and compared it to those of the above-mentioned families. We found that the common white sucker possesses four cone-mediated neural mechanisms similar to those in cyprinids and salmonids, but it does not exhibit polarization sensitivity. In addition, unlike cyprinids and salmonids, the common white sucker shows a random cone mosaic in the centro-temporal retina. These results suggest that polarization sensitivity in ultraviolet-sensitive ®shes requires an ordered double-cone mosaic in this area of the retina.
Revista Brasileira de Zoologia, 1999
The retina of MelYllnis roosevelti Eigenmann , 19 15, a velY active treshwater fish , was investigated by light and electron microscopy and was found to have a complex neuronal structure that all ows rapid responses of visual stimuli. Retina photo receptors are double cones, single long cones, single short cones and rods. Cone inner segments are alTanged as mosaics. The outer nuclear layer contains small nuclei of twin cones, long and wide nuclei ofl ong single cones, spherical large nuclei of short cones, and small dense nucl ei of rods. Horizontal, amacrine, bipolar and gang lion neUl'ones are responsible for connections and integration between photoreceptor cells and afferent neurones. The pigmented epithelium comprises a single layer of cylindrica l ce lls each wi th elongated nuclei, mitoc hondri a at the basal region, and melan in grains that can migrate inside long cell processes, depending on li ght intensity. Tn darkness, pigment is concentrated in the basal region of the cells and in daylight it is concentrated in the processes, surrounding and protecting the outer segments of photoreceptors. When exposed ex perim entally to monochromatic red light, expansion of melanin pigments was provoked at the beginning of li ght period, followed by their withdrawal ailer exposure to long wave lengths. No active movements of cones or rods were observed. Considerable renewa l of photoreceptor membrane discs occurred after one week in red li ght, caused by hi gher level of activati on of rods to allow the fi sh to see in relative darkness. Me tYlIllis roosevelti is a native fish from Brazilian tropica l and sub-tropica l regions. More recently trials were made to use it in ti sh cultures in difterent regions of the countlY. Its capacity to adjust to different photic env iron ments fac ilitates for rearing in vari ed environments. KEY WORDS. Fish, retina, morphology, red light Fish are influenced by many environmental factors one of the most important of which is li ght. Light either directly or indirectly affects vital processes such as reproduction, development, migrations, swi mming activities, search for food, territorial defence, and detection of predators (N
The UV visual world of fishes: a review
Journal of Fish Biology, 1999
Ultraviolet-A radiation (320-400 nm) is scattered rapidly in water. Despite this fact, UV is present in biologically useful amounts to at least 100 m deep in clear aquatic environments. Discovery of UV visual pigments with peak absorption at around 360 nm in teleost cone photoreceptors indicates that many teleost fishes may be adapted for vision in the UV range. Considering the characteristic absorption curve for visual pigments, about 18% of the downwelling light that illuminates objects at 30-m depth would be available to UV-sensitive cones. Strong scattering of UV radiation should produce unique imaging conditions as a very bright UV background in the horizontal view and a marked veiling effect that, with distance, obscures an image. Many teleosts have three, or even four, classes of cone cells mediating colour vision in their retina and one can be sensitive to UV. These UV-sensitive cones contain a visual pigment based on a unique opsin which is highly conserved between fish species. Several powerful methods exist for demonstration of UV vision, but all are rather demanding in terms of technique and equipment. Demonstration that the eye lacks UV-blocking compounds that are present in many fish eyes is a simpler method that can indicate the possibility of UV vision. The only experimental evidence for the use of UV vision by fishes is connected to planktivory: detection of UV-opaque objects at close range against a bright UV background is enhanced by the physical properties of UV light. Once present, perhaps for the function of detecting food, UV vision may well be co-opted through natural selection for other functions. Recent discovery that UV vision is critically important for mate choice in some birds and lizards is a strong object lesson for fish ecologists and behaviourists. Other possible functions amount to far more than merely adding a fourth dimension to the visible spectrum. Since UV is scattered so effectively in water, it may be useful for social signalling at short range and reduce the possibility of detection by other, illegitimate, receivers. Since humans are blind to UV light, we may be significantly in error, in many cases, in our attempts to understand and evaluate visual aspects of fish behaviour. A survey of the reflectance properties of skin pigments in fishes reveals a rich array of pigments with reflectance peaks in the UV. For example, the same yellow to our eyes may comprise two perceptually different colours to fish, yellow and UV-yellow. It is clearly necessary for us to anticipate that many fishes may have some form of UV vision. 1999 The Fisheries Society of the British Isles 921 0022-1112/99/050921+23 $30.00/0 1999 The Fisheries Society of the British Isles