Abstract
Flunitrazepam (Rohypnol®, Roche, Basel, Switzerland), which is similar to chloroquine, has an affinity to melanin in retinal cells. However, in contrast to chloroquine, it does not induce structural alterations in these cells or in adjacent tissues of pigmented mice and cats even after treatment for 6 and 12 months with respectively, 2000-times (mice) or 130-times (cats) the effective human daily dose. Treatment with chloroquine (with a dose similar to that used in human anti-rheumatic therapy) over the same period, resulted in the appearance of numerous membranous cytoplasmic bodies in the retinal ganglion cells of mice and cats. In addition, in cats, an augmentation of lysosomal structures in the pigment epithelium, chiefly in the melanin-free region, and destruction of the tapetal cells were observed. Moreover, the pigment epithelium with the highest concentration of melanin was unaffected in mice and only slightly affected in cats. It was concluded that the retinotoxic effect of chloroquine is not the result of its affinity to melanincontaining tissues. Consequently, the affinity to melanin-containing cells per se is not sufficient to class a substance as potentially harmful to vision.
Zusammenfassung
Flunitrazepam (Rohypnol) bindet sich, wie das retinotoxische Chloroquin, an melaninhaltige Strukturen im Auge. Mäuse und Katzen wurden mit 30 mg/kg bzw. 2 mg Flunitrazepam/kg behandelt. Diese Menge entspricht etwa der 2000- bzw. 130fachen täglichen Dosis beim Menschen. Nach6- oder 12monatiger Behandlung wurden keine Veränderungen in Retinazellen oder im benachbarten Gewebe beobachtet. Nach der Verabreichung von Chloroquin in der Größenordnung der therapeutischen Dosis für Rheumapatienten wurden jedoch in den Ganglienzellen der Katzen- und der Mausretina optisch dichte Partikel, die vorwiegend aus Membranen aufgebaut sind, beobachtet. Zudem wurde vorwiegend im melaninfreien Teil des Pigmentepithels der Katze eine Zunahme von lysosomalen Strukturen gefunden. In der gleichen Fundusregion (Tapetum lucidum) verursachte die Chloroquin-Behandlung eine Zerstörung der auffälligen Stäbchenstruktur in den Tapetum-Zellen. Das Pigmentepithel mit dem größten Gehalt an Melanin war in der Maus nicht und in der Katze nur geringfügig verändert. Daraus folgern wir, daß der retinotoxische Effekt von Chloroquin nicht durch seine Bindung an Melanin ausgelöst wird. Die Melaninaffinität genügt deshalb nicht, um eine Substanz als potentiell gefährlich für das Sehen zu erklären.
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References
Abraham R, Hendy R (1970a) Irreversible lysosomal damage induced by chloroquine in the retinae of pigmented and albino rats. Exp Mol Pathol 12:185–200
Abraham R, Hendy R (1970b) Effects of chronic treatment on lysosomes of rat liver cells. Exp Mol Pathol 12:148–159
Allison AC, Young MR (1964) Uptake of dyes and drugs by living cells in culture. Life Sci 3:1407–1414
Bernstein H, Zvaifler N, Rubin M, Mansour AM (1963) The ocular deposition of chloroquine. Invest Ophthalmol 2:384–392
Cerletti, A., Meier-Ruge W (1967) Toxicological studies on phenothiazine induced retinopathy. Proc Eur Soc Study Drug Toxicity 9:170–188
Dale AJD, Parkhill EM, Layton DD (1965) Studies on chloroquine retinopathy in rabbits. JAMA 193:241–243
Essner E, Gorrin GM, Griewski RA (1978) Localization of lysosomal enzymes in retinal pigment epithelium of rats with inherited retinal dystrophy. Invest Ophthalmol Visual Sci 17:278–288
François J, De Rouck A, Cambie E, De Laey JJ (1972) Rétinopathie chloroquine. Ophthalmologica (Basel) 165:81–99
François J, Maudgal MC (1964) Experimental chloroquine retinopathy. Ophthalmologica (Basel) 148:442–452
Gleiser CA, Bay WW, Dukes TW, Brown RS, Read WK, Pierce KR (1968) Study of chloroquine toxicity and a drug-induced cerebrospinal lipodystrophy in swine. Am J Pathol 53:27–45
Gorn RA, Kuwabara T (1967) Retinal damage by visible light: A physiologic study. Arch Ophthalmol 77:115–118
Gregory MH, Rutty DA, Wood RD (1968) Retinal changes and chloroquine. Br Med J 2:428–429
Gregory MH, Rutty DA, Wood RD (1970) Differences in the retinotoxic action of chloroquine and phenothiazine derivatives. J Pathol 102:139–150
Harcourt RB, Dobbs RH (1968) Ultrastructure of the retina in Tay-Sachs disease. Br J Ophthalmol 52:898–902
Haudenschild C, Studer A (1971) Early interactions between blood cells and severely damaged rabbit aorta. Eur J Clin Invest 2:1–7
Hobbs HE, Sorsby A, Freedman A (1959) Retinopathy following chloroquine therapy. Lancet II:478–480
Hodgkinson BJ, Kolb H (1970) A preliminary study of the effect of chloroquine on the rat retina. Arch Ophthalmol 84:509–515
Karnovsky MJ (1965) A formaldehyde-glutaraldehyde fixative of high osmolality for use in electron microscopy. J Cell Biol 27:137–138
Kuhn H (1980) Autoradiographic evidence for the binding of [3H]flunitrazepam (Rohypnol) to melanin granules in the cat eye. Experientia 36:863–865
Kuhn H, Steiger A (1981) Structural alterations of retinal tapetal cells of cats induced by prolonged treatment with chloroquine. Cell Tissue Res 215:263–269
Lindquist NG (1973) Accumulation of drug on melanin. Acta Radiol (Suppl) 325:1–92
Mackenzie AH, Scherbel AL (1969) Let us abandon some chloroquine dogmas. Arthritis Rheum 12:315
Meier-Ruge W (1967) Medikamentöse Retinopathie. Thieme, Stuttgart
Noell WK, Walker VS, Kang BS, Berman S (1966) Retinal damage by light in rats. Invest Ophthalmol 5:450–473
Potts AM (1962) The concentration of phenothiazines in the eye of experimental animals. Invest Ophthalmol 1:522–530
Potts AM (1964) The reaction of uveal pigment in vitro with polycyclic compounds. Invest Ophthalmol 3:405–416
Ramsey MS, Fine BS (1972) Chloroquine toxicity in the human eye. Am J Ophthalmol 73:229–235
Redmann G (1977) Halbautomatische Bildanalyse mit dem MOP und dem MOP/AM 01. Mikroskopie 33:102–107
Reijngoud DJ, Tager JM (1976) Chloroquine accumulation in isolated rat liver lysosomes. FEBS Letters 64:231–235
Reinert H, Rutty DA (1969) Mechanism of chloroquine and phenothiazine retinopathies. Toxicol Appl Pharmacol 14:635–636
Rosenthal AR, Kolb H, Bergsma D, Huxsoll D, Hopkins JL (1978) Chloroquine retinopathy in the rhesus monkey. Invest Ophthalmol Visual Sci 17:1158–1175
Rubin M, Slonicki A (1966) A mechanism for the toxicity of chloroquine. Arthritis Rheum 9:537
Sams WM, Epstein JH (1965) The affinity of melanin for chloroquine. J Invest Dermatol 45:482–488
Terry RD, Weiss M (1963) Studies in Tay Sachs disease. J Neuropathol Exp Neurol 22:18–55
Thompson SW (1975) Chloroquine retinopathy in the rat. Vet Pathol 12:71
Weissman G (1969) The effects of steroids and drugs on lysosomes. In: Dingle JT, Fell HB (eds) Lysosomes in Biology and Pathology, Vol 1. North Holland Publishing Company, Amsterdam, p 276
Wetterholm DH, Winter FC (1964) Histopathology of chloroquine retinal toxicity. Arch Ophthalmol 71:82–87
Wiener J, Loud AV, Kimber DV, Spiro D (1968) A quantitative description of cortisone-induced alterations in the ultrastructure of rat liver parenchymal cells. J Cell Biol 37:47–61
Zvaifler NJ (1968) Antimalarial treatment of rheumatoid arthritis. Med Clin N Am 52:759–764
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Kuhn, H., Keller, P., Kovács, E. et al. Lack of correlation between melanin affinity and retinopathy in mice and cats treated with chloroquine or flunitrazepam. Albrecht von Graefes Arch. Klin. Ophthalmol. 216, 177–190 (1981). https://doi.org/10.1007/BF00408159
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DOI: https://doi.org/10.1007/BF00408159