Methyl mercury induced visual deficits in rainbow trout

Abstract

1982. Methyl mercury induced visual deficits in rainbow trout. Can. J. Zool. 60: 3127-3133. Scotopic spectral sensitivity of 15 rainbow trout was determined using a two-choice, operant-conditioning task. Maximum sensitivity occurred at 525 nm and generally declined at longer and shorter wavelengths with evidence of a "shoulder" at 600-650 nm. Fifteen days after injection with either saline control (n = 4) or 4.6-6.2 mg of methyl mercury chloride per kilogram of body weight (n = 9); measurements of response latency and trials to criterion revealed that methyl mercury (MEHG) did not affect memory or motor performance. MEHG did produce significant spectrally uniform decrements in visual sensitivity. These results suggest that MEHG impaired both the scotopic and photopic mechanisms of MEHG-treated rainbow trout. HAWRYSHYN, C. W., W. C. MACKAY et T. H. NILSSON. 1982. Methyl mercury induced visual deficits in rainbow trout. Can. J.ZOO^. 60: 3127-3133. Le spectre de sensibilitk scotopique a kt6 dktermink chez 15 truites arc-en-ciel en les soumettant a une expkrience de conditionnement opkrant, en prksence de deux choix. La sensibilitk maximale se situe a 525 nm et diminue aux longueurs d'onde plus longues ou plus courtes, mais atteint un palier a 600-650 nm. Les truites ont requ des injections d'une solution tkmoin, solution saline (n = 4), ou d'une solution de 4,6-6,2 mg de mkthyle-mercure par kilogramme de masse totale (n = 9); la mesure des temps de latence et des activitks, selon les crititres, a rkvklk que le mkthyle-mercure (MEHG) n'affecte ni la mkmoire, ni la motricitk. Le produit entraine cependant une diminution importante de la sensibilitk visuelle sur tout le spectre. Ces rksultats indiquent que le MEHG affecte a la fois les mkcanismes scotopiques et les mkcanismes photopiques chez les truites.[Traduit par le journal]

Losses of immunoreactive parvalbumin amacrine and immunoreactive alphaprotein kinase C bipolar cells caused by methylmercury chloride intoxication in the retina of the tropical fish Hoplias malabaricus

“…The same occurred in bipolar α PKC-IR cells, which are part of the rod pathway. The damage to the rod and cone pathways agrees with the behavioral findings reported by Hawryshyn et al (23) showing reduction of the scotopic and photopic spectral sensitivity.…”

“…Other effects on the visual system of fish have been described, such as alteration in the scotopic and photopic spectral sensitivity (23).…”

“…Some studies have revealed scotopic and photopic visual deficits after methylmercury exposure (22,23), but there is no evidence of the effects of methylmercury on specific retinal cell types using immunocytochemistry.…”

Effects of mercury intoxication on the response of horizontal cells of the retina of thraira fish (Hoplias malabaricus)

“…The ip design used here was applied according to Hawryshyn et al (19,26) who determined scotopic sensitivity behaviorally in the rainbow trout (Salmo gairdneri Richardson), a species that inhabits colder waters. These investigators injected the fish with 4.6 and 6.2 mg MeHg/kg and obtained reliable behavioral responses.…”

“…Hawryshyn et al (19) demonstrated a reduction of the behaviorally determined visual spectral sensitivity function in the rainbow trout injected intraperitoneally (ip) with MeHg. The reduction of sensitivity involved both photopic and scotopic mechanisms, in contrast to the previous results obtained by Fox and Sillman (18).…”