Many plants and animals are capable of developing in a variety of ways, forming characteristics that are well adapted to the environments in which they are likely to live. In adverse circumstances, for example, small size and slow metabolism can facilitate survival, whereas larger size and more rapid metabolism have advantages for reproductive success when… (More)
The exploratory behavior of two species of murid rodents, Acomys cahirinus and Mus musculus, was compared in four experiments: In the first, the responses of the two species to a novel arena were studied. Mus was found to take longer to enter the arena, and to spend more time in the relatively familiar or safer start box, than was Acomys. The results… (More)
The ultrasonic calls produced by three day old mice when separated from the nest mother and siblings increase in number when naloxone is injected.
Acomys cahirinus is a precocial murid and a comparison of its development with altricial species of the same family, such as the rat and mouse, may shed some light on the relationship between genetic and environmental factors in the development. The use of Acomys in neurobehavioural studies and its comparison with mouse and rat may be particularly… (More)
Three histamine H1-receptor antagonists, chlorpheniramine, diphenhydramine and tripelennamine, were tested alone or in combination with morphine, amphetamine and scopolamine on locomotor activity in mice. All three antihistaminics, at some dosage levels, enhanced morphine-induced hyperactivity, but did not change or even reduce locomotor stimulation induced… (More)
Various categories of the motor behavior were recorded using a video tape in mice subjected to a 10 min activity session in a toggle-floor box after an ip administration of saline solution, d-amphetamine (2 or 4 mg/kg), morphine (10 or 20 mg/kg) or scopolamine (0.5 or 1 mg/kg). While all the three drugs enhanced horizontal activity, in particular the… (More)
Morphological studies have been made of the neocortical and archicortical structures in the spiny mouse Acomys cahirinus, the only maturely born species from the family Muridae. The data obtained reveal highly developed hippocampus as compared to the neocortex in this mouse, in contrast to relationships found in other mice and rats.
Acomys cahirinus, the spiny mouse, is the only precocial murid. Given the relatively advanced state of neural maturation at birth, this species is therefore of interest for comparative studies of brain and behavioural development. Previous work on this species has indicated that (i) hippocampal thickness (relative to body weight) is greater in adult Acomys… (More)
6-day-old mice pups were injected with D-amino acids (D-phenyl-alanine + D-leucine), and their ultrasonic distress vocalizations were measured. D-Amino acids, which exert opioid-like effects, reduce the number of ultrasonic calls without affecting the activity of the pups. This effect is reversed by naloxone, an opioid antagonist. The role of endogenous… (More)