Acta biologica Academiae Scientiarum Hungaricae最新文献

The growth of cells of ventral sebaceous gland of Rhombomys opimus was studied in diffusion chambers. The surface properties of these cells and intercellular contacts have been examined in the scanning electron microscope. After 10 to 12 days of cultivation the cells formed aggregates showing a recognizable histological pattern (the ventral sebaceous gland). The pituitary and ovarian gland explants had a significant effect on the differentiation and mitotic activity of epithelial cells of the ventral sebaceous gland. Apparently it is the cell surface itself that alters during the active processes of secretion and differentiation.

Golgi and electron microscopic observations of the neostriatum of macaque monkeys reveal the presence of thin axons of extrinsic origin which produce a profuse arborization of very fine beaded branches. The varicosities contain pleomorphic synaptic vesicles, and may form strongly asymmetric axospinous synapses. Immunocytochemical methods utilizing an unlabeled antibody against serotonin followed by peroxidase-antiperoxidase complex and further histochemical visualization demonstrate that some elements conforming to the above description exhibit specific immunoreactivity. Relatively few of the labeled profiles form synapses and did so with small dendritic spines. In these cases the membrane specializations are strongly asymmetric. The neuropil also contains many unstained elements of similar morphology. The findings provide the morphologic features of serotoninergic axons in the neostriatum. Their properties may be shared by other monoaminergic afferents. It is suggested that serotonin is released as a neurotransmitter from synapsing boutons, and as a neuromodulator from non-synapsing varicosities. This distinction may correlate with the serotonin receptors 1 and 2 which apparently are responsible for excitatory and inhibitory actions respectively.

The anterograde transport of horseradish peroxidase was used to stain nerve fibers in the hypothalamic median eminence of the rat. Bundles of commissural fibers were found coursing in the subependymal layer. They approach the median eminence along the basal surface of the diencephalon, and seem to terminate contralaterally in the medio-basal hypothalamus. The relatively thick fibers of the magnocellular fiber system were seen in the internal zone. Along their rostro-caudal trajectory the fibers join into bundles which surround elongated fields. The varicose fibers of the parvicellular system run rostro-caudally in the dorsal part of the external (palisade) zone, while they become randomly oriented more ventrally, i.e. adjacent to the portal capillaries. It is tentatively suggested that tanycyte processes around the median eminence form a barrier system localizing the substances secreted by the nerve terminals of the parvicellular fiber system. Tanycyte processes within the median eminence seem to divide the palisade zone into rostro-caudally elongated compartments allowing only transverse diffusion in the extracellular space.

The effects of 10 ppm CuSO4, ZnCl2 on the blood glucose level and serum LDH, GOT, GPT activities of three fish species (carp, silver carp, European wels) were measured. CuSO4 increased the blood glucose level, LDH, GOT and GPT activities in the three species in the following order: silver carp greater than carp greater than European wels. ZnCl2 did not alter the same levels. Our results showed that CuSO4, and presumably several anthropogenic agents, damaged the different fish species specifically and caused different stress effects depending on the fish species.

Using the double ink-filling technique the arteries and veins of the lateral hypothalamus are described in detail. This region occupied mainly by the fibres and interposed cells of the medial forebrain bundle is supplied by some own arteries and branches of the large basal vessels. Most of the arteries running to the rostral part of the lateral hypothalamus originate from the internal carotid, others belong to the anterior and middle cerebral arteries. Blood supply of the middle part comes from the middle hypothalamic and three tuberal arteries. All arteries of the caudal part originate from the posterior communicans. The abundant drainage of the lateral hypothalamus is collected by the basal and anterior interpeduncular veins from the rostral two-thirds and the caudal one-third, respectively.

Islets were isolated from the pancreas of female rats by using the collagenase technique. After culturing for 4 days, the islets were taken for measurement of insulin release biosynthesis as well as glucose utilization in subsequent short-time incubations. A low glucose concentration was insufficient to maintain a glucose-stimulated insulin release in vitro. A high glucose concentration had a protecting and restoring effect on the insulin release: ultrastructurally, such islets showed signs of an active biosynthesis in the electron micrograph. The enhancement of Mg++ in the culture medium resulted in an improvement of insulin storage in the islets, accompanied by a well-preserved action of glucose in a subsequent incubation.

Changes in contractility and ATPase activity of SR from hearts of hypothyroid rats were investigated. Rats were made hypothyroid by daily injection of 100 mg/kg methimazole for 14 days. In methimazole-treated rats, the contractile force, the maximum velocity of tension development and relaxation were significantly decreased, however, the time to peak tension remained unchanged. Function of SR was studied by determining of Ca2+-activated ATPase activity, which was significantly decreased after methimazole treatment. This diminution may be partially responsible for a slower reduction of the free Ca2+ in the surroundings of contractile proteins and thus decrease the rate of relaxation.