Ultrastructure of the hypothalamo-neurohypophysial system in rats exposed to lead. I. Magnocellular nuclei.

The effect of lead on ultrastructure of supraoptic and paraventricular neurons was studied in rats allowed to drink lead acetate solution instead of water during 6 weeks. Generally, the neurosecretory neurons appeared to be sensitive to lead dependently on its concentrations, but the ultrastructural patterns of the individual neurons varied from cell to cell and suggested the co-existence of the neurons in different functional states such as the increased secretory activity, adaptive responses or cellular degeneration.

Ultrastructure of the hypothalamo-neurohypophysial system in rats exposed to lead. II. Neurohypophysis.

Ultrastructure of neurohypophysis was examined in rats allowed to drink for 6 weeks only solution of lead acetate. It was found the increased number of neurosecretory granules in axonal terminals, the signs of granulolysis in Herring bodies and the presence of axonal terminals with atypical, heterogeneous contents. The possible mechanisms of alterations observed in the whole hypothalamoneurohypophysial system affected by lead were discussed.

Morphological pattern of the hypothalamo-neurohypophyseal system in acute intoxication with 2,4-dichlorophenoxyacetic acid [2,4-D].

The amount and distribution of the neurosecretory material in the hypothalamo-neurohypophyseal system were investigated in rats sacrificed 24 hours, 3 or 14 days after single intragastric administration of 2,4-D acid or physiological solution. The amount of the neurosecretory material increased in the whole system after 24 hours and then it decreased on the 3rd and on the 14th day after administration of 2,4-D acid.

Changes of neurosecretory material content in neurohypophysis of rats submitted to chronic treatment with copper.

The effect of copper on neurosecretory material (NSM) content in neurohypophysis of rats was investigated. The control group of animal was treated with deionized water, the others with copper sulphate solutions containing 3.6 or 12 mg Cu/dm3 for 7 or 14 days. Sections of neurohypophysis were stained by the method reflecting the neurosecretion content in this organ. It was found that copper induces an accumulation of NSM in neurohypophysis. Such an effect depends on the concentration of copper in solutions and on time of treatment.

[Morphological picture of the spinal ganglia in guinea pigs exposed to general vibration]. / Morfologiczny obraz zwojów rdzeniowych swinek morskich poddanych oddzialywaniu ogólnej wibracji.

In the spinal ganglia of guinea pigs exposed to general vibration of 40 Hz frequency and 1 mm amplitude for 3 hrs daily, gradually increasing morphological lesions were found after 7, 14, 30 and 90 days of the experiment. The animals exposed to vibration for up to 30 days exhibited a decrease in the cell nuclei volume, increase in the occurrence of eccentric and marginal cell nuclei and nucleoli, as well as an increase in the number of multiple nucleoli. After 90 days' exposure, such severe lesions as tigrolise, vacuolar degeneration of the cytoplasm, granular disintegration of the myelin sheaths or proliferation of glial cells were found.

[Morphological characteristics of the changes in the prosencephalon of guinea pigs exposed to general vibrations]. / Charakterystyka morfologiczna zmian powstalych w przodomózgowiu swinek morskich pod wplywem ogólnej wibracji.

After 7 or 30 days of exposure to general vibration (frequency: 40 Hz, amplitude: 1 mm) for 3 hours per day, the prosencephalon of guinea pigs exhibited a wide range of morphological changes, including congestion, haemorrhages, the presence of the heterochromic neurons and perivascular spaces as well as diffuse spongiosis. In contrast, after 14 days' exposure to general vibration of the same parameters, diffuse spongiosis of the prosencephalon was found in all the animals under examination. Hypothalamus, cerebral cortex and periventricular gray matter were unaffected by spongiosis in most of the animals. The nerve fibre sheats were unchanged in all cases.

[Vibration-induced morphological changes in the brain stem and spinal cord of the guinea pig]. / Zmiany morfologiczne w pniu mózgu i rdzeniu kregowym swinek morskich pod wplywem wibracji.

Some disorders of the brain stem and spinal cord microcirculation were observed in male adult guinea pigs exposed to vertical vibration of frequency 40 Hz and amplitude 1 mm for 3 hours daily during 7, 14, 30 days. These changes after 7 days of vibration were seen as congestion with single small haemorrhages and after 14 days as diffuse spongiosis of the brain stem and spinal cord. After 30 days both congestion with haemorrhages and spongiosis were noted but the first predominated.

The morphodynamic patterns of the paraventricular nucleus in rats under experimental conditions. II. Neurosecretory activity.

A relationship between the morphodynamic pattern of both the PVN and neurosecretory cells scattered in the hypothalamus and the time elapsed after the animal's last meal was found. The necessity for controlling the feeding time of animals in experiments on PVN activity is emphasized.

The morphodynamic patterns of the paraventricular nucleus in rats under experimental conditions. I. Cytoarchitectonic studies.

An elaboration of the cytoarchitectonics of the PVN and the topography of the neurosecretory cells scattered in the anterior hypothalamus in rats subjected to various experiments is presented. The most distinct and complete patterns were obtained from rats with experimental occlusion of the small intestine, in the early post-laparotomy period and after withdrawal of food and water for periods of 6, 12, 24 hours. A hitherto undiscovered group of neurosecretory cells was found in the stria terminalis and single cells of that type near the anterior commissura.

[Karyometric studies of the ventral cochlear nucleus in kanamycin treated guinea pigs (author's transl)]. / Karyometrische Untersuchungen am Nucleus ventralis cochleae bei mit Kanamycin behandelten Meerschweinchen

The aim of these investigations was to study the effect of kanamycin on the nucleus ventralis cochleae in guinea pigs. The evaluation of the results was based on the karyometric method which is a very sensitive criterion of the cell activity. In the same animals, the microphonic potential (PM) and the nerve action potential (AP) were measured in order to detect changes in the peripheral auditory system. The results were statistically analysed. The studies showed that despite marked changes in the PM and AP values, there were no changes in the cell volume in the nucleus ventralis cochleae. The findings indicate that the injuries induced by kanamycin are localized peripherally and the later central morphological changes reported in the literature can be assumed to be secondary resulting from the damage to the peripheral auditory system by kanamycin.