Ultrastructural and biochemical studies of the brain and other organs in rats after chronic ethanol administration. IV. Stereological analysis of mitochondria from rat liver cells after intoxication with various ethanol doses.

Ultrastructural and stereological analysis of mitochondria of liver cells from rats was performed after intoxication with various doses of ethanol administered for various time periods in increasing concentrations. The following changes were observed in the cells of the experimental animals as compared with the control ones: -- a decrease of the surface area of mitochondria per unit volume of the hepatocyte, -- a decrease of the mean number of mitochondrial profiles per 100 micrometers 2 surface area of hepatocyte cross section, -- a decrease in the value of the axial ratio of mitochondrial profiles. A diminished volume fraction of the mitochondria was not observed. The above presented results show that, after ethanol poisoning, the mitochondria in hepatic cells become enlarged and rounded and their number seems to diminish. Qualitative studies demonstrated that the structure of mitochondria is frequently damaged, this consisting in injury to their membranes, formation of lamellar structures, and destruction of the system of cristae and matrix. This leads to the presence of degenerated, sometimes monstrously large mitochondria in the cells. The above described changes occurred as early as after 4 weeks of ethanol administration in increasing doses from 2.5 to 10 per cent. An increase of ethanol concentration to 42 per cent and prolongation of the period of treatment with ethanol to 12 weeks did not markedly enhance the changes.

Ultrastructural and biochemical studies of the brain and other organs in rat after chronic ethanol administration. III. Influence of ethanol intoxication on oxidative phosphorylation of the rat brain mitochondria with ultrastructural and morphometric evaluation of mitochondrial fraction).

The effect of chronic ethanol intoxication on oxidative phosphorylation in the rat brain mitochondrial fraction was examined. Moreover, electron microscopy was used to verify the quantitative composition of the fraction and for examination of ultrastructural changes in the mitochondria. The experiments were carried out with 60 rats receiving, beside the normal diet, ethyl alcohol according to a modified RATCLIFFE model. In isolated rat brain mitochondria the NAD-dependent oxidation of substrates (glutamate + malate) was decreased. The phosphorylation index ADP/0 and the respiratory control ratio (RCR) in rat brain mitochondria from ethanol-treated rats were unchanged in the presence of both succinate and glutamate + malate. Chronic ethanol feeding did not induce any changes of succinate dehydrogenase and cytochrome oxidase activities in solubilised mitochondria fractions of rat brain. Electron microscopy studies revealed that mitochondria from control animals retained their outer and inner membranes, whereas those from rats given ethanol were almost always swollen and some were disrupted. In mitochondrial fractions isolated from ethanol-intoxicated rats an increase was observed of contaminating elements i.e. axons and synaptosomes of various sizes. It should be stressed that the mitochondria located inside synaptosomes and axons were unchanged. The composition of the fractions was quantitatively evaluated and confirmed the diminution of "free" mitochondria in the experimental fractions in favour of "bound" mitochondria which mainly occurred in the synaptosomes with preserved metabolic activity. On the basis of electron microscopy studies it could be suggested that ethanol intoxication causes the damage of some mitochondria, which become more sensitive to mechanical destruction during isolation procedure, and they do not sediment together with the fraction of normal ones. The absence of "free" mitochondria in pellets explains the spurious lack of disturbances in the energy metabolism of brain mitochondria after chronic ethanol intoxication.

Ultrastructural and biochemical studies of the brain and other organs in rats after chronic ethanol administration. I. Electronmicroscopic investigations of the morphologic elements of the blood-brain barrier in the rat after ethanol intoxication.

The aim in view was to establish whether chronic administration of ethanol causes ultrastructura changes in the brain of rats, particularly in the structures through which alcohol penetrates to the brain, that is the cerebral cortex capillaries. The experiments were performed with 5 Wistar rats, three of which received ethanol according to RATCLIFFE'S model for 8 weeks in increasing concentrations from 2.5 to 25 per cent. Two rats served as control. In the endothelium of some capillaries of the brain cortex in the rats ingesting ethanol an enlargement of the cell nuclei was observed. The number of mitochondria in the cytoplasm and of micropinocytic vesicles was found to increase, and proliferation of the smooth endoplasmic reticulum and Golgi system were noted. Considerable oedema was observed in the astrocytic processes surrounding the vessels, with the presence of numerous mitochondria of abnormal shape and huge size. Oedema of perivascular astrocytic processes and enhanced pinocytosis seem to indicate an increased permeability of the blood-brain barrier as the result of the toxic effect of ethanol.

[Dynamics of synaptic changes in experimental audiogenic epilepsy]. / Dynamika zmian w synapsach w przebiegu doswiadczalnej padaczki audiogennej

The dynamics of ultrastructural changes in axonal endings were studied after experimental epileptic seizures. Mice and rats from strains with genetically--determined audiogenic epilepsy were used as a model of epilepsy. The animals were divided into 3 groups: in group 1 only one seizure was evoked, in group 2 eight seizures within 4 hours, group 3 served as control. The animals were killed immediately after the last seizure, 30 min. after it or 1 hour after the seizure. Hippocampal gyrus cortex was impregnated with zinc-iodide-osmium tetroxide and synapses were examined under electron microscope. The number of synaptic vesicles showing positive reaction with zinc iodide was calculated in 20 synaptic boutons in each group. A significant correlation was demonstrated between the frequency of seizures and the survival time after the seizure on the one hand, and synaptic changes, on the other. In the control group 97% of synaptic vesicles were filled with neurotransmitter substance giving positive reaction with zinc iodide. Immediately after the single seizure 46% of synaptic vesicles were found emptied, 30 min. later the neurotransmitter substance was demonstrated in 79% of vesicles, 1 hour later 82% of vesicles had normal appearance. Immediately after serial seizures 91% of vesicles were found empty, 30 min. later the neurotransmitter was present in 50% of vesicles, 1 hour later in 78%. In another group of animals seizures were evoked once daily for 40 days (chronic epilepsy model). Synaptic changes were different: the synaptic boutons were swollen, the number of vesicles was reduced, greatly enlarged vesicles and clear membrane-bound vacuoles appeared. They evidenced degenerative character of changes. It is suggested that degenerative synaptic changes may be a substrate of epileptic dementia.