Neonatal 6-hydroxydopamine-induced dopamine depletions: motor activity and performance in maze learning.

Three experiments were performed to study the effect of dopamine (DA) depletions, induced by neonatal intracerebroventricular (ICV) treatment with 6-hydroxydopamine (6-OHDA), upon measures of spontaneous motor activity. Instrumental learning for food reward in an Olton radial arm maze and escape learning from a large, circular water maze were studied also. Motor activity was measured by direct observation of rats in a modified radial arm maze and by use of automated test cages equipped with photocell devices.

Hyperactivity and instrumental learning deficits in methylazoxymethanol-treated rat offspring.

Several changes of spontaneous motor and learned behaviours were obtained in the male offspring of pregnant rats that were treated on gestation day 15 with the antimitotic agent methylazoxymethanol (MAM, 25 mg/kg). MAM-treated offspring, when tested at adult ages, showed notable increases in motor activity parameters as measured by direct observation or in automated photocell test cages. This hyperactive state was accompanied by clear impairments by MAM offspring in the acquisition of instrumental learning in a radial arm maze and in a circular swim maze.

Lack of effects of prenatal exposure to lidocaine on development of behavior in rats.

The objective of this investigation was to study the effects of lidocaine upon postnatal development of the rat. Lidocaine, 6 mg/kg (21 mumol/kg), was given to a group of 12 rats. Injections were administered intramuscularly, bilaterally in the masseter muscles, once a day on days 10 and 11 of pregnancy.

LD50 - its value for the pharmaceutical industry in safety evaluation of drugs.

Does the pharmaceutical industry perform LD50-determinations in animals just because it is required by the authorities or are there any scientific benefits from counting dead animals and calculating and index of lethal toxicity? This is an important question when discussing LD50 and possible alternatives. We will try to answer this question by presenting data and some views collected during almost ten years at a Swedish pharmaceutical company. We will describe how we have made use of the LD50-values in the safety evaluation process.

Degradation of ochratoxin A by a ruminant.

The fate of ochratoxin A during incubation with contents from the four stomachs of the cow was studied. It was concluded that ochratoxin A was cleaved into the nontoxic ochratoxin alpha and phenylalanine by the contents from all but the abomasum.