[Structural alterations in pancreatic islets in streptozotocin-induced diabetic rats treated with of bioactive additive on the basis of Gymnema sylvestre].

The structural alterations in pancreatic islets in streptozotocin-induced diabetic rats were studied after the administration of Gymnema sylvestre extract or its composition. Diabetes mellitus was modeled by daily injection of streptozotocin (20 mg/kg for 5 days) and single injection of 0.2 ml of complete Freund's adjuvant, Only the animals with the blood glucose level exceeding 15 mmol/l were included in the experiment. B- and A-endocrinocytes were demonstrated using immunocytochemistry. The proportions of the area of the pancreatic islets, occupied by B- and A-endocrinocytes, as well as the volume fraction of the pancreatic islets within the pancreas, were determined. In the model of streptozotocin-induced diabetes, the part of the total islet area occupied by B-endocrinocytes, was diminished in the pancreatic islets located in all the zones of the gland. Prophylactic administration of Gymnema sylvestre extract or its composition tended to restore the area occupied by B-endocrinocytes in the pancreatic islets. These results indicate the equal potency of the composition and extract of Gymnema sylvestre to induce the regeneration of B-endocrinocytes.

Ultrastructure of neurons in the hypothalamic suprachiasmatic nucleus of rats with different stress reactivity.

The rats were divided into groups demonstrating extremely high and low stress reactivity depending on the results of testing for the nociceptive threshold and thermolability in response to bacterial lipopolysaccharide administration. Specific structural features of the nucleus and mitochondria were revealed in neurons of the hypothalamic suprachiasmatic nucleus in rats with constitutionally high reactivity, which reflects high functional activity and stress-induced lability of these structures. Ultramicroscopic study revealed phenotypic differences in one of the key hypothalamic nucleus, which enables potent and rapid neurogenic response of the stress system in animals with high stress reactivity.

[Mechanism of forming the integral hypothalamic reaction in psychoemotional overstress]. / Mekhanizm formirovaniia integral'noi reaktsii gipotalamusa pri psikhoémotsional'nom perenapriazhenii.

It has been stated that mechanism of formation of hypothalamus integral reaction in strong influence of psychoemotional overstressing differs in it's moderate or chronic influence. Hypothalamus doesn't possess expressed adapted mobility as psychoemotional overstressing arouses dystrophic alterations in neurons of paraventricular nucleus rather quickly leading to the rhythm disorders of hypothalamic secretion and further disorders in conjugated function of hypothalamic structures.

[Changes in the volumetric density of the hypothalamic neurons of rats under long-term immobilization-pain stress]. / Izmenenie ob"emnoi plotnosti neironov gipotalamusa krys pri dlitel'nom immobilizatsionno-bolevom stresse.

In the experiments on albino male rats histological and stereological alterations of hypothalamic neurones were studied during long-tern immobilization-pain stress. It was shown, that dissimilar qualitative and quantitative neuronal changes arise in the rat hypothalamus. Significant decrease in neuronal volume density, which is likely to be caused by dystrophy and cell necrosis phenomena, was seen in supraoptic, suprachiasmal, paraventricular, ventral median, dorsal premammillar, supramammillar nuclei and the anterior hypothalamus. Neurones of the ventricular premammillar nucleus were characterized by significant augmentation of volume density, apparently due to cell hypertrophy.