Aggressive behavior and stress response after oxytocin administration in male Norway rats selected for different attitudes to humans

Oxytocin (OXT) is known to influence on social behaviors, including intermale aggression and hypothalamic-pituitary-adrenal (HPA) axis activity. However, there are no data on the effects of oxytocin on intermale aggression and HPA axis activity in rats selected for elimination and enhancement of aggressiveness towards humans. The aim of this study is to elucidate the role […]

Assessment of spontaneously occurring periodic limb movements in sleep in the rat

OBJECTIVE: Periodic limb movements in sleep (PLMS) are often associated with the restless legs syndrome (RLS). Although the dopaminergic system seems to be involved, the pathophysiology of PLMS and RLS is still obscure. The objective of this study is to explore whether a PLMS-like phenomenon can be observed in rodents in order to elucidate the […]

Sleep–wake study in an animal model of acute and chronic heat stress

The study of the variations in different parameters of sleep–wake states following exposure to high environmental heat in three different age groups of freely moving rats have been presented in this paper. Each age group of rats was subdivided in three group (i) acute heat stress — subjected to a single exposure for 4 h […]

What is it like to be a rat? Rat sensory perception and its implications for experimental design and rat welfare

This review of rat sensory perception spans eight decades of work conducted across diverse research fields. It covers rat vision, audition, olfaction, gustation, and somatosensation, and describes how rat perception differs from and coincides with ours. As Nagel’s seminal work (1974) implies, we cannot truly know what it is like to be a rat, but […]

Prudent sperm allocation in Norway rats, Rattus norvegicus: a mammalian model of adaptive ejaculate adjustment

In species where there is postcopulatory competition between males in the form of sperm competition, theory predicts that males should show prudent sperm allocation. Specifically, males should adjust the number of sperm that they inseminate in response to variations in the risk and intensity of sperm competition. Some experimental evidence for nonmammalian species indicates that […]

Using the cross point of demand functions to assess animal priorities

We developed a method to assess the substitutability of two reinforcers by using the divergence of the cross point of two demand functions. Two kinds of water were used as reinforcers, namely distilled water and quinine water. We tested 16 rats, Rattus norvegicus, from two strains in a closed economy. A single demand function for […]

Rats seem indifferent between their own scent-marked homecages and clean cages

Previous large-scale, long-term studies suggest that rat welfare is little affected by cage-cleaning frequency. Here, we investigate this further using a preference test: arguably a more sensitive welfare indicator than those used previously. Nine pairs of rats were each housed in two interconnected cages of differing cleanliness. One cage was cleaned every 3–4 days, while […]

Effects of rearing and sex on maze running and competitive exploration in rats

Male and female rats in enriched environments were tested for maze learning ability, retested for retention after 30 days (Experiment 1, N = 22), and tested for exploratory behavior, designed as the competing tendency to make “irrelevant” section entry responses when allowed unobstructed, problem-free access to goal boxes (Experiment 2, N = 16). It was […]

Sex-dependent effects of chronic unpredictable stress in the water maze

Exposure to chronic predictable stress, such as restraint, can affect performance on spatial memory tasks and these effects have been shown to be sex-specific in rats. It is not known whether unpredictable stress has similar sex-specific effects on spatial memory and whether those effects are present after the stress procedure has ended. Therefore, the current […]