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Trauma or the tourniquet used in orthopedic surgery is often associated with ischemia-reperfusion (I/R) injury with a consequent decrease of muscle power. To explore whether components of the neuromuscular junction (NMJ) are involved in this muscle dysfunction, NMJs were ultrastructurally characterized in the extensor digitorum longus muscle of rats at reperfusion times of 1, 24, 72, and 168 h after a 120-min arterial occlusion. Disorganization of the presynaptic membrane and mitochondrial injury was noted at 1 h, followed by fragmentation and partial engulfment of nerve terminals by Schwann cells at 24 and 72 h. The magnitude of degenerative changes declined at 168 h, suggesting the commencement of regeneration. The postsynaptic membrane remained intact throughout the whole period. In our previous study, deafferentation with pretreatment of the sciatic nerve with capsaicin, which reduces neurogenic inflammation and has a selective effect on nociceptive fibers, improved functional recovery of the muscle after I/R. The present results document a significantly delayed structural regeneration of the motor nerve terminals after combined capsaicin and I/R treatment. Since capsaicin treatment alone had no discernible effect on the structure of NMJs, the findings point to a possibly indirect effect of capsaicin on the motor nerves, which may predispose them to increased susceptibility unmasked only by a subsequent injury. The mismatch between the enhanced functional improvement of the muscle and delayed regeneration of the nerve after capsaicin pretreatment questions the efficient use of such deafferentation to protect the integrity of neuromuscular junctions in I/R injury.

The intrinsic neuronal organisation in the nucleus of the basal optic root of chickens was investigated. The divergent connections with various areas and the functional complexity of the nucleus require a complex intrinsic structural arrangement. Therefore, an analysis of Golgi impregnated material, ultrastructure, GABA-immunocytochemistry and biotinylated dextran-amine anterograde tracer analysis of the nucleus was carried out. In the Golgi analysis, a characteristic dendritic ramification pattern of two types of putative projection neurons was observed. These neurons form dendritic nests with their overlapping dendritic terminal sections, that develop synaptic fields with the optic fibre terminals. These synaptic fields were confirmed by electron microscopy. GABA-immunopositive terminals synapse with distinct loci of the dendritic trees of projection neurons; they may therefore play an important role in the inhibitory-modulatory system of the nucleus of the basal optic root. The GABA-immunopositive terminals derive from small and/or elongated local circuit neurons which receive retinal afferents, and from myelinated fibres afferents to the nucleus of unknown origin.

The principal afferent fibres of the avian optic tectum are the optic fibres of retinal origin. They terminate on the contralateral side, in the external layers (2-7) of the optic tectum (called optic layers) turning into these layers from the external surface. The terminal branchings of the optic fibres develop four densely innervated areas in layers 2, 3, 4-5 and 7. Their terminals are large and of various appearance in the different areas. In the middle third of the optic layer (in layers 4-5), thin dendritic terminal sections of tectal ganglion cells (according to Ramòn y Cajal) of layer 13 terminate into bunches. Phaseolus vulgaris lectin immunotracer corroborates these dendritic endings (further: dendritic terminals) of tectal ganglion cells. The direct connections between these dendritic terminals and the supposed optic fibres were studied under electron microscope and it was found that the large terminals of optic fibres containing round synaptic vesicles establish asymmetrical synapses with several dendritic profiles, among them Phaseolus lectin labelled dendritic terminals of ganglion cells. This result morphologically supports the former physiological observation of a direct synaptic transmission between optic fibres and ganglion cells of layer 13. In addition, on the dendritic terminals of ganglion cells, symmetrical synapses established by GABA-positive terminals were found. The optic terminals, the GABA-immunopositive terminals and the dendritic terminals of ganglion cells form complex synaptic units surrounded with glial sheath, and thus they establish glomerulus-like synaptic units. The size of the dendritic tree and the branching pattern of the dendrites of ganglion cells point to divergence and convergence in visual transmission.

After PhA-L injection into the tectum opticum of chickens, column-like labelled terminal arborizations were found in tectum and also labelled neurons of Ipc and Imc in the corresponding sections. The PhA-L labele proved the projection from both Imc and Ipc neurons to tectum; their terminal axonarborizations were clearly discernible. Column-like terminal arborizations of different sizes were found both in PHA-L and Golgi impregnated preparations. GABA immunostaining displayed GABA positive neurons in Imc. The EM-Golgi study corroborated that the axon-terminals of Imc neurons established symmetrical synapses in the tectum. The results of the present study support the existence of an inhibitory feedback loop from Imc neurons to the tectum.

The projection from the chick optic tectum to the nucleus rotundus was investigated by iontophoresis of the anterograde tracer Phaseolus vulgaris lectin (PHA-L) into the optic tectum and by Golgi impregnation. PHA-L labelled fibres were observed within the ipsilateral nucleus rotundus and to course through the supraoptic decussation to the contralateral nucleus rotundus. They appeared similar to fibres evident in Golgi impregnated material. Before reaching the nucleus rotundus, PHA-L labelled fibres gave off short terminal branches in the caudoventral thalamic nucleus. Within the ipsilateral nucleus rotundus, the labelled fibres formed an extensive fibre net with a dense core and a less dense periphery. PHA-L labelled fibres in the contralateral nucleus rotundus exhibited a qualitatively similar but sparser distribution. There appeared to be a topographic representation of the optic tectum within the nucleus rotundus. Electron microscopy revealed that PHA-L labelled tectal fibres established asymmetric synapses with principal neurons in the nucleus rotundus.

Having injected Phaseolus Vulgaris Lectin (PhA-L) iontophoretically to subpretectal (SP) and postero-ventralis (PV) thalamic nuclei, labelled fibers and terminals appeared in nucleus rotundus (Rt). The PhA-L immunostained fibers are divided dichotomically and they develop long terminal sections with large varicosities. In EM preparates PhA-L labelled terminals were observed establishing axo-somatic, axo-dendritic symmetrical synapses. These terminals were stained by GABA immunogold procedure and proved to be GABA-ergic, i.e. the neurons of SP and PV nuclei supply the principal neurons of Rt with GABA positive terminals, which are located on specific, exponent loci of the principal neuron.

The terminals of rotundal fibers labelled with Phaseolus Lectin anterograde tracer were studied in ectostriatum periphericum and neostriatum intermedium laterale with EM. These terminals belong to the fibers which cross the ectostriatum centrale before they enter the ectostriatum periphericum and neostriatum intermedium laterale. These terminals establish synapses with dendrites, spines and also with GABA immunogold stained somata. The EM results prove the connections of ectostriatum periphericum and neostriatum intermedium laterale with the visual system.

Investigation of the chick archistriatum revealed that it was not possible to distinguish distinct sub-regions on the basis of their Golgi architecture, despite the fact that the pigeon archistriatum has been suggested to comprise "amygdaloid" and "sensorimotor" divisions. Nine sub-types of projection neuron and four of local circuit neuron were identified in the chick archistriatum. Projection neurons were generally larger with thicker dendrites than those in other regions of the chick telencephalon. A greater proportion of these projection neurons also had highly densely spiny dendrites. These findings suggest that archistriatal neurons receive a large, possibly complex afferentation and project considerable distances. Large and medium-sized local circuit neurons with varicose axon branches and relatively large neurogliaform cells were characteristic of the archistriatum. All types of archistriatal neuron were identified in both 28 and one day old chicks. However, presumptive highly densely spiny projection neurons appeared relatively immature in the one day old chick archistriatum.

Phaseolus vulgaris leucoagglutinin extracellular injection was performed in nucleus rotundus thalami and the course of labelled fibers and their termination were examined in chicken. The labelled fibers terminate in ectostriatum centrale, ectostriatum perifericum and neostriatum intermedium. The course and termination of the fibers are analysed in detailed.

After having iontophoretically injected Phaseolus vulgaris Lectin into nucleus rotundus, labelled terminals were examined in ectostriatum centrale by EM. These terminals contained round synaptic vesicles. They were observed earlier by Golgi method and proved to be of rotundal origin by Phaseolus Lectin tracing method. The labelled terminals establish synapses, on large and small dendritic truncs of projection and local circuit neurons, and also contact spines and dendritic processes of projection neurons. They were observed on soma of GABA immunopositive local circuit neurons, and also on dendrites. Some observations completed the already known data on fine structure of the chicken ectostriatum centrale.

The EM preparates displayed in the nucleus rotundus also symmetrical type of synapses with flattened vesicles, known this type as inhibitory synapsis. To prove this supposition and to find the sources of inhibitory terminals GABA-immunostaining was applied in the diencephalon of chicks. The preparates were examined by light- and electronmicroscope. In nucl. rotundus the large terminal profiles on the cell membrane of principal neurons, on the dendrites and branching areas of terminal branchings of dendrites proved to be GABA positive. The sources of GABA-ergic fibers seemed to be the subpretectal and ventral posterior thalamic nuclei.

The analysis of EM structure of nucleus rotundus completes the results got by Golgi study. The fine structure of neurons and neuropil of the nucleus and the synaptic relations were studied by EM. The fine structural details of principal neuron were described. Several synapses of symmetrical type with flattened vesicles in large terminals contacted the cell body and also the origin and proximal part of the main dendrites. In the neuropil synaptic junctions were formed by terminals that contained (1) spherical vesicles with occasionally very few dense core vesicles, (2) flattened synaptic vesicles. Terminals that contained spherical vesicles were associated with asymmetric synaptic densities, and terminals that contained flattened vesicles formed symmetric junctions. Synapses of asymmetric type associated mostly with terminal sections of dendrites forming glomerular-like structure. Synapses of symmetric type with flattened synaptic vesicles contacted the branching areas of dendritic terminals and side-branches, the origin of main dendrites and the cell surface of principal neuron.

The structural arrangement of nucleus rotundus was studied by Golgi method. Large, multiangular principal neurons, their dendrites and dendritic terminals were observed. The long dendrites and their side-branches course parallel and/or perpendicular to each-other and they are arranged about in dorso-ventral latero-medial and rostro-caudal directions. The dendrites and their side-branches develop characteristic terminal branchings. These dendritic terminals overlap each-other and the area is called dendritic terminal field. The tecto-rotundal fibers traverse the nucleus in large bundles and the final sections of fibers join to the dendrites of principal neuron and terminate in dendritic terminal fields.

In Golgi impregnated ectostriatum centrale of telencephalon of one-day-old chicken two types of neuron: projection neuron and interneuron with large axonal field and varicose axonal preterminals and terminals, were identified and examined in EM preparates. In the serial EM sections the morphological features of the two neurons types were observed. The projection neuron is characterized by the few axo-somatic synapses on the cell membrane, which are of symmetrical type. The INs, however, have numerous axo-somatic synapses on cell membrane both of symmetrical and asymmetrical types. Also the axonterminals were analysed.

The projection from the ventral tegmental area of Tsai (VTA-A10) to the hippocampal formation (HF) has been investigated in the rat by means of the Fink-Heimer technique, after VTA destruction by electrolytic lesions or local injections of 6-hydroxydopamine (6-OHDA, 1 microgram/0.5 microliters). Degenerated axons prevail in the ventral subiculum and adjacent CA1 field. Some degenerated fibers are also observed in the dorsal subiculum and a few in the stratum oriens of the CA3, in the hilus of fascia dentata and in the fimbria. The distribution of VTA neurons projecting to the HF has also been examined by injecting retrograde fluorescent tracers in different combinations (Fast Blue, 2% and Nuclear Yellow, 1%) in several hippocampal areas. The most abundant VTA-HF projections originate from the lower third, the upper and lower edges and the lower half of the VTA. The major terminal fields of VTA projections in the HF (i.e. the ventral subiculum, the adjacent CA1 field and the dorsal subiculum) match with the HF area projecting to the nucleus accumbens. Thus, the dopaminergic meso-limbic pathway could modulate the HF-striatal projection which provides a link between the limbic and motor systems.

The study demonstrates one kind of the afferent fibers in ectostriatum in Golgi preparates. These fibers enter the ventro-medial border of the area. The primary section and further course and branches, as well as the terminal arborization of these fibers were observed. Also the maturation process of the branchings of the fibers was studied in the Golgi preparates after hatching. The fiber-networks found in one-day-old and 28-day-old chicken ectostriatum centrale were compared.

The brains of kittens prenatally exposed to ethanol were studied by the rapid-Golgi method at PN1 and PN9 days. The sizes of the alcohol damaged brains were different. Delayed gyrification was observed on the brain surface. The neurons in subcortical (thalamic) centres and cortical areas developed later than in normal animals. Between days PN1 and PN9 rapid changes occurred in the development of the structural elements of brains of prenatally alcohol exposed kittens.

The medial septal nucleus of non-experimentally treated albino rats was investigated electron microscopically. According to former light microscopical findings most of the dendrites in this region are spineless but conspicuously varicose. Besides a striking diminution of the packing density of neurotubules inside the varicosities--compared with the narrow portions of varicose dendrites--some organelles like multivesicular bodies, lamellated bodies and cisterns of the smooth endoplasmic reticulum were found to be characteristic of them. Large neuronal somata rich in RER with a broad rim of cytoplasm around the nucleus and numerous lipofuscin-like granules occur. But there are numerous small cells exhibiting a narrow rim of cytoplasm and pourly developed RER, too. At least six classes of synaptic junctions can be distinguished, three of the asymmetric and three of the symmetric type. Most of axo-somatic contacts are of the symmetric type, at the dendrites asymmetric contacts dominate. Presynaptic profiles with large dense-core vesicles form symmetrical contacts with varicose and non-varicose dendritic profiles.

In the Golgi preparation of visual Wulst of chicken four types of projection neurons were found: type 1a, 1b, 1c, and 1d neurons, which are distinguished on the basis of their dendritic ramification pattern and especially on the density of the dendritic spines. Type 1a has large dendritic tree with moderately dense spiny dendrites. Type 1b has very dense spiny dendrites. Type 1c is a small neuron with moderately dense spiny dendrites. Type 1d is a star-pyramid-like neuron with a short, bifurcating apical dendrite. The final dendritic pattern and spine density of projection neurons was found to develop at the end of the first month. In the Wulst short axon cells (interneurons-INs) of different types occur: large, medium-sized and small INs can be observed. Their axon-arborizations are significantly different from each other. Some of them are GABA-immuno-positive neurons, which are very probably inhibitory interneurons. Stellate-like neurons also occur in IHA and HIS. These neurons have sparsely spiny dendrites and locally arborizing axons.

Our investigations try to reveal the morphological changes found postnatally at different levels and centres of central nervous system of kittens of cats chronically treated with ethanol during their pregnancy and lactation. The changes found in neurons of lateral geniculate nucleus (LGN) were analyzed in Golgi-stained preparations from brains removed on the first or on the ninth postnatal days. The data were computerized. The changes measured in neurons refer to their maturation process: a significant delay of differentiation of the neurons occurs in LGN. Also a delayed gyrification of brains was observed.

The Golgi method more than hundred years old can reveal new results also in the current research of CNS. The study provides examples for using the Golgi method and demonstrates the types of neurons, the various types of interneurons, characterizes the stellate cells in layer IV of the cortex. The Golgi method is applicable for the observation of maturation process and also for demonstrating different pathological alterations of neurons in the CNS.

An attempt is made on the definition of proportional distribution of the different types of neurons in the layers of LGN by means of quantitative method. On the basis of nuclear volume, nuclear and cell diameters the different types of neurons were separated according to their size and shape. The ratio of relay and interneurons proved to be 2:1 in all layers of LGN of cat. The proportional distribution of further subgroups of neurons was also defined. The bilateral connections between the relay and interneurons based on initial axon collateral of TCR neurons and on axon terminals and dendritic appendages of INs, are also calculated. The interneurons--in the LGN--have widespread contacts with both types of relay neurons, similarly the relay neurons contact the interneurons. The numerical data of morphological observations are accord with the results of physiologists.

In the hippocampus, antibody raised against vasoactive intestinal polypeptide (VIP) labeled perikarya and processes of non-pyramidal neurons whereas these structures remained unlabeled in pyramidal cells and granule cells. In the present study, VIP-immunostaining was used to investigate the fine structure and synaptic connections of identified non-pyramidal neurons and of immunoreactive axon terminals in the CA1 region of the rat hippocampus by means of electron microscopic immunocytochemistry. From a number of cells studied, two VIP-like immunoreactive non-pyramidal neurons in the regio superior were selected for an electron microscopic analysis of serial thin sections. These cells were different with regard to the location of their cell bodies and the orientation of their dendrites. One cell was located in the stratum lacunosum-moleculare with dendritic processes oriented parallel to the hippocampal fissure. The second neuron was found in the inner one-third of the stratum radiatum. The dendrites of this cell ran nearly parallel to the ascending apical dendrites of the pyramidal cells. Both cells had a round or ovoid perikaryon and an infolded nucleus. The aspinous dendrites of both neurons were densely covered with synaptic boutons. These terminals were small, filled with spherical vesicles, and established asymmetric synaptic contacts. No variations in the fine structure of the presynaptic boutons were found along the course of the labeled dendrites through the various hippocampal layers, although different afferents are known to terminate in these layers. Vasoactive intestinal polypeptide-like immunopositive axon terminals course through all layers of the hippocampus. In the stratum pyramidale they established symmetric synaptic contacts with the perikarya of pyramidal cells. In the stratum radiatum they made symmetric contacts with the shafts of apical dendrites of pyramidal cells but never contacted dendritic spines. The symmetric contacts with pyramidal cell perikarya suggest an involvement of the VIP-like immunoreactive axon terminals in pyramidal cell inhibition.