Melanopsin photoreception in the eye regulates light-induced skin colour changes through the production of α -MSH in the pituitary gland

2015 ◽  
Vol 28 (5) ◽  
pp. 559-571 ◽  
Author(s):  
Gabriel E. Bertolesi ◽  
Carrie L. Hehr ◽  
Sarah McFarlane
Keyword(s):  
Pituitary Gland ◽  
Skin Colour ◽  
Colour Changes

scholarly journals The pigmentary effector system VII—The chromatic function in Elasmobranch fishes

1936 ◽  
Vol 120 (817) ◽  
pp. 142-158 ◽  
Keyword(s):  
Pituitary Gland ◽  
Colour Change ◽  
Anterior Lobe ◽  
Physiological Mechanisms ◽  
Rapid Responses ◽  
Effector System ◽  
Aquatic Vertebrates ◽  
Colour Changes ◽  
Elasmobranch Fishes ◽  
Phylogenetic Character

It is now firmly established that the coordination of chromatic response in Amphibia is predominantly, if not exclusively, due to the liberation of hormones by reflexes involving visual and skin receptors, and in Reptiles to direct innervation of the pigmentary effector organs (Hogben and Mirvish, 1928; Zoond and Eyre,1934). Among aquatic vertebrates examples of both types of coordination occur. The bulk of available evidence points to the conclusion that the chromatophores of Teleostean fishes are directly innervated and that the comparatively rapid responses which are exhibited by several species are brought about by simple reflex action. That this is not true of cyclostomes has recently been shown by J. Z. Young (1935) whose experiments demonstrate the archaic phylogenetic character of the control exercised by the Amphibian pituitary gland. From an evolutionary standpoint it would not be surprising to find among physiological mechanisms in Teleostean fishes examples of specialization comparable to the strikingly aberrant features which their anatomical organization displays. On the other hand it would be remarkable if the cartilaginous fishes proved an exception to a rule which applies both to Cyclostomes and to Amphibia. Recent work on the colour changes of Elasmobranchs supports the conclusion that the coordination of colour change in Teleostean fishes is highly specialized. Lundstrom and Bard (1932) have shown that total removal of the pituitary gland in Mustelis canis results in a state of pallor which ensues within a few hours after operation, reaching its limit about the twelfth post-operative hour. In their experiments the animals usually succumbed after three or four days with loss of righting reactions. Only a few survived as long as a week. The effect was not produced by removal of the anterior lobe alone, nor by severe traumatization of the hypothalamus. Complete darkening of the pale operated animals followed injections or extracts of ox pituitary and of the pituitary of the fish itself, the quantity present in the fish gland being greatly in excess of the amount requisite to induce full expansion of the dermal melanophores. The present investigation, undertaken to throw further light on the evolution of the chromatic function in Vertebrates, is based on several species of Elasmobranch fishes, namely the skates, Raia Brachiura, R. clavata, R. maculata, R. microcelatus , the speckled dogfish Scyllium canicula , the banded dogfish or nursehound S. catulus (Scylliorhinusstellaris) , and the monkfish Rhina squatina . The writer is indebted to Mr. G. A. Steven for invaluable assistance in identifying the various species used. In all these species the pigmentary effector system of the integument, like that of the American dogfish Mustelis canis , closely resembles that of Amphibia, and consists of three types of chromatophores which are more or less evenly distributed. These are the epidermal melanophores, larger more richly branched dermal melanophores, and xanthophores containing an orange yellow pigment. The same agencies, in the fishes to be described, evoked or maintained pigment diffusion (“expansion”) of all three types, and the concentration of pigment in the centre of the cell (“contraction”) in all three types. That is to say, the xanthophores of a skate or dogfish which was maximally pale were always fully contracted like the melanophores of both kinds, and the xanthophores of a dark animal were fully expanded. This is true of some—but not all—Amphibia. In general appearance the chromatophores of the species studied are more like those of a Urodele than those of a Teleost.

Reflectance spectrophotometric quantification of skin colour changes induced by topical corticosteroid preparations

1982 ◽  
Vol 106 (4) ◽  
pp. 437-444 ◽  
Author(s):  
J. W. FEATHER ◽  
K.S. RYATT ◽  
J.B. DAWSON ◽  
J.A. COTTERILL ◽  
D.J. BARKER ◽  
...  
Keyword(s):  
Topical Corticosteroid ◽  
Skin Colour ◽  
Colour Changes

Postural Skin Colour Changes during the Corticosteroid Blanching Assay

1999 ◽  
Vol 12 (4) ◽  
pp. 199-210 ◽  
Author(s):  
F. Henry ◽  
I. Fumal ◽  
G.E. Piérard
Keyword(s):  
Skin Colour ◽  
Colour Changes

scholarly journals A colorimetric comparison of sunless with natural skin tan

2020 ◽  
Author(s):  
Kinjiro Amano ◽  
Kaida Xiao ◽  
Sophie Wuerger ◽  
Georg Meyer
Keyword(s):  
Principal Component ◽  
Critical Factor ◽  
Skin Colour ◽  
Control Group ◽  
Naturally Occurring ◽  
Median Error ◽  
Natural Range ◽  
Colour Changes ◽  
The Difference ◽  
Cielab Colour

AbstractThe main ingredient of sunless tanning products is dihydroxyacetone (DHA). DHA reacts with the protein and amino acid composition in the surface layers of the skin, producing melanoidins, which changes the skin colour, imitating natural skin tan caused by melanin. The purpose of this study was to characterise DHA-induced skin colour changes and to test whether we can predict the outcome of DHA application on skin tone changes.To assess the DHA-induced skin colour shift quantitatively, colorimetric and spectral measurements of the inner forearm were obtained before, four hours and 24 hours after application of a 7.5% concentration DHA gel in the experimental group (n = 100). In a control group (n = 60), the same measurements were obtained on both the inner forearm (infrequently sun-exposed) and the outer forearm (frequently sun-exposed); the difference between these two areas was defined as the naturally occurring tan. Skin colour shifts caused by DHA tanning and by natural tanning were compared in terms of lightness (L*), redness (a*) and yellowness (b*) in the standard CIELAB colour space. Naturalness of the DHA-induced skin tan was evaluated by comparing the trajectory of the chromaticity distribution in (L*, b*) space with that of naturally occurring tan. Twenty-four hours after DHA application, approximately 20% of the skin colour samples became excessively yellow, with chromaticities outside the natural range in (L*, b*) space. A principal component analysis was used to characterise the tanning pathway. Skin colour shifts induced by DHA were predicted by a multiple regression on the chromaticities and the skin properties. The model explained up to 49% of variance in colorimetric components with a median error of less than 2 ΔE. We conclude that the control of both the magnitude and the direction of the colour shift is a critical factor to achieve a natural appearance.

EFFECT OF NEMBUTAL AND NIALAMIDE ON THE PARS INTERMEDIA AND SKIN COLOUR CHANGES IN RANA CYANOPHLYCTIS SCHNEIDER

1971 ◽  
Vol 68 (2) ◽  
pp. 264-270 ◽  
Author(s):  
N. H. Gopal Dutt ◽  
M. R. Rajasekharasetty
Keyword(s):  
Skin Colour ◽  
Prolonged Treatment ◽  
Pars Intermedia ◽  
Histochemical Analysis ◽  
Pentobarbital Sodium ◽  
Low Concentration ◽  
Colour Changes ◽  
Melanophore Stimulating Hormone ◽  
Stimulating Hormone

ABSTRACT The administration of pentobarbital sodium (nembutal) at low concentration causes darkening of the skin. However, at higher dose or after prolonged treatment a moderate blanching of the skin is noticed. Nialamide also produces a moderate blanching effect. Both these drugs considerably increase the number of colloid vesicles in the pars intermedia of the frog, Rana cyanophlyctis. These drugs, however, do not reverse the darkening of the skin due to ACTH in hypophysectomized frogs. Histochemical analysis suggests that the colloid vesicles may represent stored melanophore-stimulating hormone.

Morphological skin colour changes in teleosts

2009 ◽  
Vol 11 (2) ◽  
pp. 159-193 ◽  
Author(s):  
Eric Leclercq ◽  
John F Taylor ◽  
Hervé Migaud
Keyword(s):  
Skin Colour ◽  
Colour Changes

Observations on skin colour changes in juvenile lumpsuckers

1995 ◽  
Vol 47 (1) ◽  
pp. 143-154 ◽  
Author(s):  
J. Davenport ◽  
C. Bradshaw
Keyword(s):  
Skin Colour ◽  
Colour Changes
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