Daniel Bovet

Effects of nicotine on avoidance conditioning of inbred strains of mice.

SummaryAvoidance conditioning of inbred strains of mice was used to analyse the effects exerted by genetic factors on the action of nicotine. The experiments were carried out through an automatic programming and recording “shuttle box” device. The results indicate that the effects of nicotine are strain dependent. A facilitating effect on avoidance conditioning was observed in 6 of the 9 inbred strains, the strains characterized by a low performance showing generally the highest degree of facilitation. In two strains with a very high level of performance there was an impairing effect of nicotine on avoidance performance.

Effects of post trial administration of drugs on avoidance learning of mice

Abstract Post trial injections of strychnine and picrotoxin enhanced avoidance learning of mice trained in a shuttle-box avoidance task. Post trial administration of nitrous oxide induced instead an impairment of the performance. Learning was affected--enhanced or impaired--only when the treatment was given within a few minutes after training. The results are discussed on the basis of the processes involved in memory storage.

Effects of age on maze learning and avoidance conditioning of mice.

Abstract The effects of age on maze learning and avoidance conditioning have been studied on DBA/2J mice under massed and distributed practice. Sixty days old mice showed the best performance when compared to younger or older animals. The results are interpreted by suggesting a lower efficiency of the long term memory storage processes in both young (21 days) and old (180–360 days) mice.

Relations between avoidance and activity: A diallel study in mice

A genetic study of shuttle-box avoidance learning and wheel-running activity was conducted in a diallel study by using five inbred strains of mice and their twenty F1 hybrid crosses. The results show that in general terms the mode of inheritance (directional dominance or heterosis) depends on the strains and on the traits considered. Significant negative correlations were evident for the strains used. These findings suggest that the rates of avoidance learning and motor activity are determined by many of the same genes.

Short and long term memory in two inbred strains of mice

Abstract Conditioned avoidance behavior has been studied in two strains of mice by using different training schedules. The strain C3H/He reached a higher performance when the trials were massed while DBA mice showed a better retention by distributing practice. The results are discussed on the basis of a dual mechanism of memory storage.

The effects of different amino acid diets on a fast-induced performance decrement in mice.

In mice subjected to long uninterrupted avoidance sessions (1,500 trials) a clear decrement of performance was evident after the first 500–600 trials. Mice subjected to a 24 h fast showed a more rapid decrement of performance during the session following the fasting period than that evident in the same group fed ad libitum.When the effects of feeding casein, glucose or different amino acids were assessed, only casein, glucose or serine prevented the impairment of performance while the most toxic amino acids, i.e. histidine, methionine and tryptophan diminished the performance below that obtained by fasting. Casein, glucose and serine were the only diets that maintained blood glucose levels within the normal range. Feding experiments showed that serine was the most acceptable aminoacid to the mice indicating that it was unique in maintaining performance because it is the only amino acid that is both palatable and readily gluconeogenic.

The effect of iproniazid and tranylcypromine studied with a dark-avoidance conditioned schedule

Different groups of rats were first trained with a dark avoidance conditioned schedule of the shuttle-box technique. Subsequently different doses of iproniazid and tranylcypromine were injected i.p. and their effects upon the levels of conditioning were measured according to a specific time-table, different for the two drugs.While iproniazid, at doses of 25.50 and 100 mg/kg almost always induced a decrease of the percentage of the conditioned responses, tranylcypromine, at doses of 2.5 and 5 mg/kg, caused a marked increase of the same, 5 h after its administration.Such percentage increase of the C.A.R. seems to be temporally related to the marked increase of brain nor-epinephrine induced by this latter drug, also 5 h after its administration.A comparative study between tranylcypromine and d-amphetamine shows the advantages of this particular type of schedule to distinguish between different classes of central nervous system stimulating drugs.