Biomedical subjects
Publications and source records attributed to A Oliverio.
The tail-flick latency, measured using radiant heat as a noxious stimulus, was significantly shorter in C57BL/6 than in DBA/2J mice, while no significant interstrain differences were observed in the hot-plate test. The experiments in which the animals' tail was painted indicated that the difference in the tail-flick latency between strains was caused by the difference in the color of animal's coat.
The effects of amineptine and cocaine on locomotor activity were studied in two sets of experiments, by using C57BL/6 mice. In a first set, activity enhancements were evident following acute administration of both drugs. In addition to that the effects of amineptine were additive with those of cocaine. In a second set of experiments, mice developed tolerance to the stimulatory effects of both amineptine and cocaine, and a clear cross-tolerance effect was evident in mice chronically injected with these drugs. The results are discussed in terms of the involvement of dopaminergic mechanisms in the activity stimulating action of amineptine.
In C57BL/6 mice caffeine antagonized morphine-induced hyperactivity. This effect was most evident when caffeine was used in doses that slightly increased locomotor activity. Given at the same dose caffeine did not affect morphine-induced analgesia. Two possibilities of explanation of this effect are discussed: action of caffeine on dopaminergic mechanisms responsible for morphine-induced running fit through its effect on cyclic AMP level, and a direct action of caffeine on delta opiate receptors involved in the stimulatory effect of morphine.
Clonidine, 0.25 and 0.5 mg/kg, depressed significantly the running fit induced by 10 or 20 mg/kg of morphine in C57BL/6 mice, but did not affect morphine analgesia measured by the "hot plate" test. The results confirm the hypothesis that different mechanisms are involved in the two types of response to morphine, and the running fit response is mediated via a noradrenergic mechanism of action.
A number of studies dealing with electrographically defined wakefulness, NREM sleep, REM sleep and locomotor activity patterns in M. musculus are reviewed. The effects of genetic and environmental factors on postnatal maturation of the EEG and on sleep patterns of adult mice are considered. The effects of short light-dark cycles and of constant light on sleep and activity rhythms of different strains of mice suggest that there are different pacemaker mechanisms which regulate circadian sleep and activity rhythms and that the expansion of these mechanisms is regulated by the genetic factors.