The ultrastructure of the compound eye ofMunida rugosa (Crustacea: Anomura) and pigment migration during light and dark adaptation

1990 ◽  
Vol 205 (3) ◽  
pp. 243-253 ◽  
Author(s):  
Edward Gaten
Keyword(s):  
Dark Adaptation ◽  
Compound Eye ◽  
Pigment Migration

Changes of Acuity during Light and Dark Adaptation in the Dragonfly Compound Eye

1990 ◽  
Vol 45 (1-2) ◽  
pp. 137-142 ◽  
Author(s):  
Eric J. Warrant ◽  
Robert B. Pinter
Keyword(s):  
Dark Adaptation ◽  
Time Course ◽  
Light Adaptation ◽  
Compound Eye ◽  
Sensitivity Function ◽  
The State ◽  
Intracellular Recordings ◽  
Acceptance Angle ◽  
Angular Sensitivity ◽  
Rapid Reduction

Abstract Intracellular recordings of angular sensitivity from the photoreceptors of Aeschnid dragonflies (Hemianax papuensis and Aeschna brevistyla) are used to determine the magnitude and time course of acuity changes following alterations of the state of light or dark adaptation. Acuity is defined on the basis of the acceptance angle, Δρ (the half-width of the angular-sensitivity function). The maximally light-adapted value of Δρ is half the dark-adapted value, indicating greater acuity during light adaptation. Following a change from light to dark adaptation, Δρ increases slowly, requiring at least 3 min to reach its dark-adapted value. In contrast, the reverse change (dark to light) induces a rapid reduction of Δρ , and at maximal adapting luminances, this reduction takes place in less than 10 sec.

Spectral sensitivity of screening pigment migration in the compound eye ofManduca sexta

1983 ◽  
Vol 153 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Richard H. White ◽  
Mark J. Banister ◽  
Ruth R. Bennett
Keyword(s):  
Spectral Sensitivity ◽  
Compound Eye ◽  
Screening Pigment ◽  
Pigment Migration

Adaptation in the Compound Eye and Interaction with Screening Pigment

1972 ◽  
Vol 56 (1) ◽  
pp. 119-128
Author(s):  
U. YINON
Keyword(s):  
Dark Adaptation ◽  
Light Adaptation ◽  
Compound Eye ◽  
Electrical Response ◽  
Negative Potential ◽  
Neural Pathways ◽  
Photochemical Process ◽  
Screening Pigment ◽  
The Difference ◽  
Adaptation Processes

The electroretinogram pattern in the compound eye of T. molitor and the appearance of irregular small potentials and spikes superimposed on the ERG are influenced during dark and light adaptation procedures. The amplitude of the principal negative potential reflects bleaching and recovery of the photochemical process. This is not true for the latency values. The delay of the electrical response increases in the dark and decreases in the light adapted eye. These changes were influenced by the intensity of the adapting light. Mutant eyes only lack screening pigment and have normal visual neural pathways. The absence of this pigment lowered the threshold sensitivity of the unscreened eye in dark adaptation. The difference between the adaptation processes in mutants and normal animals has been suggested as a criterion for measuring the net effect of the screening pigment in the compound eye.

scholarly journals Studies on the Relation between the Pigment Migration and the Sensitivity Changes during Dark Adaptation in Diurnal and Nocturnal Lepidoptera

1960 ◽  
Vol 44 (1) ◽  
pp. 205-215 ◽  
Author(s):  
C. G. Bernhard ◽  
D. Ottoson
Keyword(s):  
Functional Significance ◽  
Dark Adaptation ◽  
Retinal Pigment ◽  
Second Phase ◽  
Adaptive Process ◽  
Dark Adaptation Curve ◽  
Tentative Hypothesis ◽  
Pigment Migration ◽  
Sensitivity Changes ◽  
Insect Eye

The functional significance of the pigment migration in the compound insect eye during dark adaptation has been studied in diurnal and nocturnal Lepidoptera. Measurements of the photomechanical changes were made on sections of eyes which had been dark-adapted for varying periods of time. In some experiments the sensitivity changes during dark adaptation were first determined before the eye was placed in the fixation solution. No change in the position of the retinal pigment occurred in Cerapteryx graminis until the eye had been dark-adapted for about 5 minutes. The start of the migration was accompanied by the appearance of a break in the dark adaptation curve. During longer periods of dark adaptation the outward movement of the pigment proceeded in parallel with the change in sensitivity, the migration as well as the adaptive process being completed within about 30 minutes. In the diurnal insects chosen for the present study (Erebia, Argynnis) the positional changes of the retinal pigment were insignificant in comparison with the movement of the distal pigment in Cerapteryx graminis. On the basis of these observations the tentative hypothesis is put forward that the second phase of adaptive change in nocturnal Lepidoptera is mediated by the migration of the retinal pigment while the first phase is assumed to be produced by the resynthesis of some photochemical substance. In diurnal insects which have no appreciable pigment migration the biochemical events alone appear to be responsible for the increase in sensitivity during dark adaptation.

Reversed Light Reaction of the Screening Pigment in a Compound Eye Induced by Noradrenaline

1987 ◽  
Vol 42 (7-8) ◽  
pp. 973-976 ◽  
Author(s):  
Achim Juse ◽  
Gunnar Höglund ◽  
Kurt Hamdorf
Keyword(s):  
Compound Eye ◽  
Local Application ◽  
Pigment Cells ◽  
Light Stimulation ◽  
Light Reaction ◽  
Transmission Microscopy ◽  
Normal Dispersion ◽  
Screening Pigment ◽  
Pigment Migration ◽  
Deilephila Elpenor

Migration of the screening pigment in the compound eye of the sphingid moth Deilephila elpenor is altered by noradrenaline, as shown by microreflectometric measurements on eyes of intact moths and by transmission microscopy on preparations consisting of the screening pigment cells and dioptric structures. Local application of noradrenaline inverts the reaction of the pigment to light stimulation; light causes a contraction of the pigment instead of the normal dispersion. It is suggested that catecholamines are involved in the normal regulation of pigment migration.

Conditional inhibition of screening-pigment aggregation by lidocaine in crayfish photoreceptors and frog retinal pigment epithelium

1992 ◽  
Vol 166 (1) ◽  
pp. 197-214
Author(s):  
R. Mondragon ◽  
E. Frixione
Keyword(s):  
Retinal Pigment Epithelium ◽  
Dark Adaptation ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Ionic Balance ◽  
Rpe Cells ◽  
Ringer’S Solution ◽  
Pigment Migration ◽  
Conditional Inhibition ◽  
Pigment Aggregation

Lidocaine, at concentrations equal to or lower than those that inhibit fast axoplasmic transport, was found to interfere with the dark-adapting migration of the screening pigments along crayfish photoreceptors and within the cells of the frog retinal pigment epithelium (RPE). The effects of the anesthetic on pigment movements were studied in isolated eyes incubated under light or dark conditions in media of different ionic compositions. Treatment of crayfish eyes with 25 mmol l-1 lidocaine in normal Van Harreveld's saline arrested pigment migration to the dark-adapted position or caused migration towards the light-adapted position in the dark. Similar results were obtained with frog eyecups exposed to 5 mmol l-1 lidocaine in Ringer's solution. In each case, the inhibition of dark adaptation was reversible and dependent on the levels of Na+ and Ca2+ in the incubation medium. A dark-adapted position of both pigments was compatible with lidocaine treatment provided that low-Na+, or high-Ca2+ or Co(2+)-containing solutions were used. These results indicate that light-adapted and dark-adapted pigment positions in both types of retinal cells can occur in the absence of local nervous input. Further, the data suggest a direct effect of lidocaine upon the photoreceptors or RPE cells. The inhibition of pigment aggregation is interpreted to be a consequence of an anesthetic-induced increase in the permeability of the plasma membrane, which in turn affects the intracellular ionic balance that controls pigment position.

The eye of Anoplognathus (Coleoptera, Scarabaeidae)

1975 ◽  
Vol 188 (1090) ◽  
pp. 1-30 ◽  
Keyword(s):  
Refractive Index ◽  
Point Source ◽  
Dark Adaptation ◽  
Compound Eye ◽  
Visual Fields ◽  
Optomotor Response ◽  
Clear Zone ◽  
Acceptance Angle ◽  
Single Plane ◽  
Receptor Layer

The night flying scarabaeid beetle Anoplognathus provides an example of a dark-adapted clear-zone compound eye in which rays from a distant point source, entering by a large patch of facets, are imperfectly focused upon the receptor layer. The optical system of the eye was investigated by six methods, all of which give similar results: (1) ray tracing through structures of known refractive index, (2) measurement of visual fields of single receptors, (3) measurement of the divergence of eyeshine, and (4) of the optomotor response to stripes of decreasing width, and (5) by direct observation of distribution of light within the eye. Finally (6) anatomically there is no single plane upon which an image could be focused. In each ommatidium, beneath the thick cornea, with its short corneal cone, lies a non-homogeneous crystalline cone (range of r. i. 1.442-1.365) that is significant in partially focusing rays across the wide clear zone (340 μm) in the dark-adapted eye. On the proximal side of the clear zone the rhabdoms form 7-lobed columns, isolated from each other over half their length by a tracheal tapetum. In the light-adapted eye the cone cells extend to form a crystalline tract (70-90 μm long) which is sur­rounded by dense pigment, and the optical path across the clear zone is completed by retinula cell columns that are of higher density than the surrounding cells. Pigment movement upon adaptation takes about 10 min to complete. Dark adaptation can be induced only at night on account of a strong diurnal rhythm. Eyeshine can be seen in the dark-adapted eye so long as the distal pig­ment leaves free the tips of the crystalline cones. Eyeshine falls to 50% at an angle of 12° from the direction of a parallel beam shining on the eye, as is consistent with a partial focus in which the distribution of light on the receptor layer is 18°-24° wide at the 50% contour. This distribution was confirmed by direct examination of the inside of the eye and by measure­ment of receptor fields as follows. The mean acceptance angle for 13 light-adapted units was 12.57° ± 1.97° s. d. and that of 10 dark-adapted ones 20.3° ± 3.36° s. d. The sensi­tivity to a point source on axis is increased at least 1000 fold by dark adaptation. Rays traced through a scale drawing of the eye, with refractive index measured for each component, show how the eye as a whole comes to be partially focused, and predicts an acceptance angle of 12° in the light-adapted and 20°-24° in the dark-adapted eye. In optomotor experiments dark-adapted Anoplognathus does not respond to stripes narrower than 18° repeat period, but light-adapted beetles respond down to 10°. The optomotor experiments also show a 1000 fold increase in sensitivity when dark-adapted at night. The eye has poor acuity that goes with wide visual fields of its recep­tors, and this is surprising when other excellently focused clear zone eyes are known. A possible compensation for the poor acuity is that the aperture of the eye can be larger, so that sensitivity although only to large objects, is that much increased.

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