Brief exposure to light initiates screening pigment migration in retinula cells of the crayfish,Procambarus

1978 ◽  
Vol 125 (1) ◽  
pp. 91-96 ◽  
Author(s):  
Richard F. Olivo ◽  
Melissa E. Larsen
2017 ◽  
Vol 3 (1) ◽  
Author(s):  
Aya Satoh ◽  
Finlay J. Stewart ◽  
Hisaharu Koshitaka ◽  
Hiroshi D. Akashi ◽  
Primož Pirih ◽  
...  

1983 ◽  
Vol 153 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Richard H. White ◽  
Mark J. Banister ◽  
Ruth R. Bennett

1987 ◽  
Vol 42 (7-8) ◽  
pp. 973-976 ◽  
Author(s):  
Achim Juse ◽  
Gunnar Höglund ◽  
Kurt Hamdorf

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.


1993 ◽  
Vol 185 (1) ◽  
pp. 1-16
Author(s):  
I. G. Gleadall ◽  
K. Ohtsu ◽  
E. Gleadall ◽  
Y. Tsukahara

The extent of screening-pigment (SP) migration in the intact octopus retina and the amplitude of the early receptor potential (ERP) correspond with the degree of adaptation to light or darkness. The light-adapted retina has SP granules concentrated in an apical layer, at the tips of the photoreceptor rhabdoms and supporting cells, and the ERP is barely detectable. In the fully dark-adapted retina, the SP granules are mostly at the base of the rhabdoms, and the ERP is at its maximum. Retinae at intermediate stages, between the fully dark- and light-adapted states, show corresponding intermediate stages of SP migration and ERP amplitude. A series of experiments demonstrates the effects on SP migration of the efferent nerves, which form a subset of fibres in the optic nerves. When the optic nerves to one half of the retina have been severed, there is a dramatic difference in the distribution of SP in areas of the retina (of the dark-adapted eye) connected with severed or intact nerves: apical versus basal, respectively. On incubation of a light- adapted retina with 5 micromolar dopamine, but not with other catecholamines or other putative neurotransmitter substances, SP migrates basally and the ERP is significantly larger than for controls. In octopuses treated with reserpine, SP stays in an apical location and the ERP remains very small, regardless of the state of adaptation and of whether the optic nerves are intact. It is concluded that dopaminergic efferents from the optic lobes effect dark-adaptational SP migration in the cephalopod retina. The arrival in the retina of efferent signals that effect adaptational changes through the mediation of dopamine is a remarkable analogue of the vertebrate system.


1974 ◽  
Vol 63 (1) ◽  
pp. 22-36 ◽  
Author(s):  
N. W. Daw ◽  
A. L. Pearlman

The migration of the screening pigment was investigated in the retina of the intact squid. The action spectrum of pigment migration corresponds to the action spectrum of the visual pigment, rhodopsin, rather than to the absorption spectrum of the screening pigment. The total number of quanta required for a fixed criterion of pigment migration is the same, when the quanta are delivered over any period of time from 6 s to an hour or more. When less than 3–10% of the rhodopsin is isomerized, the screening pigment migrates out to the tips of the receptors with a time-course of 5–15 min, and back again over the same period of time. When rather more than 10% is isomerized, the outward migration takes 5–15 min, but the screening pigment does not migrate inwards, even after several hours in the dark. Indirect evidence suggests that the band of screening pigment, when it reaches the tips of the receptors, is approximately equivalent to a filter of 0.6 log units. The spectral sensitivity of the optic nerve response was measured, and was found to be broader than the absorption spectrum of squid rhodopsin in vitro; the broadness could be explained by self-screening, assuming a density of rhodopsin of 0.6 log units at 500 nm.


1969 ◽  
Vol 9 (3) ◽  
pp. 377-IN8 ◽  
Author(s):  
P.A. Liebman ◽  
S. Carroll ◽  
A. Laties

Sign in / Sign up

Export Citation Format

Share Document