Quinine blindness

A.P. Vladychensky (Russian. Oft. Zh., 1925, No. 8) observed 3 such cases. In one of them, at 55 y.o., the blindness came after those done within 4 months. 10 subcutaneous injections of 4% quinine solution, in the amount of 50.0 each time.

Alcohol preferring P rats exhibit aversion resistant drinking of alcohol adulterated with quinine

Understanding why some people continue to drink alcohol despite negative consequences and others do not is a central problem in the study of alcohol use disorder (AUD). In this study, we used alcohol preferring P rats (a strain bred to prefer to drink alcohol, a model for genetic risk for AUD) and Wistars (control) to examine drinking despite negative consequences in the form of an aversive bitter taste stimuli produced by quinine. Animals were trained to consume 10% ethanol in a simple Pavlovian conditioning task that paired alcohol access with an auditory stimulus. When the alcohol was adulterated with quinine (0.1 g/L), P rats continued to consume alcohol+quinine at the same rate as unadulterated alcohol, despite a demonstrated aversion to quinine adulterated alcohol when given a choice between adulterated and unadulterated alcohol in the home cage. Conversely, Wistars decreased consumption of quinine adulterated alcohol in the task, but continued to try the alcohol+quinine solution at similar rates to unadulterated alcohol. These results indicate that following about 8 weeks of alcohol consumption P rats exhibit aversion resistant drinking. This model could be used in future work to explore how biological basis of alcohol consumption and genetic risk for excessive drinking lead to drinking that is resistant to devaluation.

Better the devil you know: avian predators find variation in prey toxicity aversive

Toxic prey that signal their defences to predators using conspicuous warning signals are called ‘aposematic’. Predators learn about the toxic content of aposematic prey and reduce their attacks on them. However, through regulating their toxin intake, predators will include aposematic prey in their diets when the benefits of gaining the nutrients they contain outweigh the costs of ingesting the prey's toxins. Predators face a problem when managing their toxin intake: prey sharing the same warning signal often vary in their toxicities. Given that predators should avoid uncertainty when managing their toxin intake, we tested whether European starlings ( Sturnus vulgaris ) preferred to eat fixed-defence prey (where all prey contained a 2% quinine solution) to mixed-defence prey (where half the prey contained a 4% quinine solution and the other half contained only water). Our results support the idea that predators should be more ‘risk-averse’ when foraging on variably defended prey and suggest that variation in toxicity levels could be a form of defence.

Increased thirst and hunger in adult rats undernourished as infants: an alternative explanation

1. Rats were undernourished in early life by feeding their mothers a restricted quantity of a good-quality diet throughout lactation. Their undernutrition continued postweaning from 25 to 42 d of age, after which they were fed ad lib. Control rats were well nourished at all times.2. Behavioural assessment of thirst was carried out on adult males. These were deprived of water for 23 h/d throughout the period of testing. Compared to control rats, previously-undernourished (PU) rats pressed a lever at a higher rate in a Skinner box to gain a water reward, drank more frequently during their first 5 min in an unfamiliar cage, and tended to run more quickly down an alleyway for water. PU rats also drank more (/kg body-weighta0.75) of a quinine solution (1 g/l) when this was available to them ad lib. as their only source of fluid.3. A second group of rats was growth-retarded during gestation and the suckling and early postweaning periods. The rats had free access to food from 42 d of age. In adulthood their ad lib. food and water consumption was measured. PU males ate and drank more (/kg body-weight0.75) than control males.4. These results indicate that adult rats which have been undernourished in early life display increased thirst. An attempt is made to explain this finding, together with their previously-demonstrated enhanced hunger drive, purely in terms of gross anatomical and physiological differences.