Distribution of neuronal nitric oxide synthase (nNOS)-immunoreactive elements in the rabbit piriform cortex

The piriform cortex (PC), the primary olfactory cortex, is involved in the processes of learning and stress response and possibly plays an important role in epileptogenic activity. The results of several recent studies suggest that those PC neurons that contain neuronal nitric oxide synthase (nNOS) may play a key role during spatial learning and in the modulation of initiation, propagation and generalisation of seizures in various experimental models and may influence neuronal vulnerability after epileptic insults. The aim of this study was to characterise the pattern of distribution and morphology of nNOS-immunoreactive elements in PC of the adult rabbit. The co-localisation of nNOS and calretinin (CR) was also studied. The pattern of nNOS-ir within the rabbit PC is similar to that described previously in other mammals. The morphology of nNOS-ir elements, namely varicose fibres and Cajal-Retzius cells, suggest that NO has an important influence on PC function. Surprisingly, in the rabbit PC nNOS-ir elements show a very low level of co-localisation with CR-ir

The pathophysiology of intracerebral haemorrhage

Spontaneous intracerebral haemorrhage carries a high mortality rate and treatment of the disease raises more questions then answers. Mass effect, ischaemia and toxicity of blood components are responsible for brain tissue damage. Initially occurring disturbances of cerebral blood flow have a temporary character and do not play a key role in the pathology of intracerebral haematoma. Oedema formatting in the 24–48 hours after intracerebral bleeding is the result of multidirectional processes. The pathological mechanism that underlines it is the function of activation of systemic complement and cascade of coagulation. In the light of these findings, further clinical and experimental investigations should be focused on these factors

The immunoreactivity of c-Fos, NGF and its receptor TrkA after open-field exposure in the central and medial nuclei of the rat amygdala

The amygdala is a critical component of the neuroanatomical stress circuit. It plays a role in the generation of responses to emotional stimuli. The central (CeA) and medial (MeA) amygdaloid nuclei are implicated in activation of the hypothalamic-pituitary-adrenocortical (HPA) axis. The immunoreactivity (-ir) of c-Fos, NGF and its receptor, TrkA, following acute and chronic open-field stress were studied in the CeA and MeA nuclei of the amygdala. The material consisted of 21 male adult rats divided into three groups: non-stressed (control) animals, rats exposed to acute (once only lasting 15 min) and chronic (15 min daily over 21 days) aversive stimulation (open-field exposure). The brains were stained with the use of immunohistochemical methods for c-Fos, NGF or TrkA. In the control rats c-Fos-, TrkA- and NGF-ir cells were observed in the nuclei studied, but the quantity varied, being moderate or high (immunoreactive to TrkA and NGF) or low (immunoreactive to c-Fos). In the animals exposed to acute open-field stress the number of c-Fos-ir, NGF-ir and TrkA-ir cells in the nuclei under examination was differentiated but higher than that in the control animals. In the animals exposed to chronic open-field stress the number of c-Fos-ir cells in the nuclei studied was similar and was smaller than those in animals exposed to acute stress. The number of TrkA-ir neurons was also lower in comparison to that in animals exposed to acute stress. However, no significant differences in the number of NGF-ir cells were observed between the groups exposed to acute and chronic stress. Diverse expression of c-Fos protein following both acute and chronic stress stimulation may prove the functional heterogeneity of the amygdaloid nuclei investigated. The decrease observed in both c-Fos- and TrkA-ir in MeA (only TrkA in CeA) of animals exposed to chronic stress may indicate the phenomenon of habituation

Developmental expression of SNAP-25 protein in the rat striatum and cerebral cortex

The developmental changes of 25-kDa synaptosomal-associated protein (SNAP-25) expression in the rat striatum and cerebral cortex were examined using Western- blotting and densitometric scanning of immunoblots. Analysis of the striatum extracts from postnatal day 0 (P0) to postnatal day 120 (P120) demonstrated that SNAP-25 is poorly expressed until P14. From this point the expression level gradually increases to reach a maximum on P60 and then decreases. The pattern of SNAP-25 expression in the rat cerebral cortex is different. Two peaks are observed, the first on P10 and the second on P60, after which the expression level decreases. These results appear to confirm the role of SNAP-25 protein in axon outgrowth and synaptogenesis in the nervous system

The shape of the inferior horn of the lateral ventricle in relation to collateral and occipitotemporal sulci

The shape of the inferior horn of the lateral ventricle has been investigated in 100 (50right and 50 left) human brain hemispheres which were fixed in 40% formaldehyde solution and cut frontally. It has been found that the shape of the inferior horn depends on the course and depth of the collateral and occipitotemporal sulci. In most cases a part from two main ventricular surfaces: The hippocampal and superolateral, there is one surface more, either the inferior - collateral eminence (Type I - 97% of cases in the posterior part of the inferior horn, 49%- in the middle and 42%- in the anterior part) or the inferolateral, adjacent to the occipitotemporal sulcus ( Type II- 0%, 26% and 35%, respectively). In a few cases both collateral eminence and inferolateral surfaces were present (Type III- 3% , 2% and 6% respectively). In type IV neither collateral eminence nor the inferolateral surface appeared (0%, 23%, 17% respectively). The authors suggest to designate the inferolateral surface, not mentioned in the literature, as the occipitotemporal eminence (of the inferior horn)

Ultrastructural organization of the visual zone in the claustrum of the cat

Data obtained by using ultrastructural and morphometric approaches revealed three types of neurons in the cat visual claustrum. The most numerous were medium-sized and large ones. They formed 3/4 of the cell population. The ultrastructural properties of those cell types were largely similar. Their cell bodies were oval, round, fusiform or triangular and contained more or less indented nuclear envelope. The cytoplasm of those cells was characterized by a high concentration of subcellular organelles and particularly rough endoplasmic reticulum. The characteristic feature of those cells was a low nucleus/cell body area ratio (47 ± 1% and 43 ± 1%, respectively). The proximal dendrites of medium-sized cells were usually wide at the base, relatively short and tapering, whereas, those arising in the large cells were often thick and had a short tapering base. The neurons described above stained by Golgi impregnation method shoved spines on their distal dendrites both under the light and electron microscopy. The retrograde axonal transport of HRP and WGA-HRP following injections into the visual cortex confirm that they are mainly projection cells, which form the ascending limb of the claustrocortical loop. The third type of neurons formed a less numerous group of small cells, which differed from the larger ones in various respects. They possessed the large nuclei with deeply indented nuclear envelope and comparatively a thin layer of cytoplasm poor in subcellular organells among which free ribosomes and mitochondria were common. The nucleus/cells body area ratio high (59 ± 2%). In Golgi preparations their dendrites did not show spines. The dendrites originating from that type of neurons were thin, long and did not possess a wide tapering base. They are mainly claustral intrinsic neurons

The corticoclaustral connections in the rat studied by means of the fluorescent retrograde axonal transport method

The corticoclaustral connections in the rat were investigated by means of the method of the retrograde axonal transport of the fluorescent tracer (Fluoro-Gold; FG), The material consisted of 20 adult Wistar rats. The fluorescent tracer was injected into the anterior, middle or posterior parts of the claustrum. The retrogradely labeled neurons were detected in the layer VI of the neocortex. Injections of the tracer into the anterior part of the claustrum resulted in, labeling of the neurons in the motor cortex. After administration of the tracer into the middle part of the insular claustrum, labeled neurons were present both in the motor and somatosensory cortices, while the injections of the tracer into its posterior part resulted in labeling of neurons in the visual cortex. Administration of the fluorescent tracer into the insular claustrum of the rat resulted in labeling of the cortical neurons of the corresponding areas of both hemispheres, however, the contralateral projections seem to be less numerous than the ipsilateral. Our results confirm the existence of reciprocal connections of the claustrum with the neocortex and suggest its role in integration and modification of information reaching the neocortex

The projection of the amygdaloid nuclei to various areas of the limbic cortex in the rat

The connections of the amygdaloid body with the areas of the limbic cortex in the rat were studied by means of the method on the axonal retrograde transport of the fluorescent tracer Fluoro-Gold. The tracer was injected into the anterior and posterior limbic cortices (cingulate gyrus, granular- and agranular retrosplenial area, respectively. The localization of the corresponding amygdalar- projection zones was investigated and the semiquantitative analysis of the connections was conducted. The projection zones in the rat amygdaloid body are organized topographically. Administration of the fluorescent tracer to the anterior and posterior part of the limbic cortex in the rat (cingulate gyrus and both retrosplenial areas, respectively) reveals labeling of cells only for injections to the former one. The labeled cells were present only in the major components of the basolateral amygdaloid complex. The main source of this projection was anterior part of basolateral nucleus (BLA). Some labeled neurons were found in the lateral nucleus and few in the ventral part of basolateral nucleus. No labeled cells were found within the basomedial nucleus

The amygdaloid body of the rabbit - a morphometric study using image analyser

The amygdaloid body is a telencephalic structure belonging to the limbic system. The amygdaloid body consists of the two main nuclear groups: corticomedial and basolateral. The former-phylogenetically older group is composed of the central, medial, and cortical nuclei, while the latter, phylogenetically younger one, of the lateral, basolateral and basomedial ones. The results presented in our paper indicate differences in the structure and topography of the specific amygdaloid nuclei. Their subdivisions in the rabbit are not as evident as in the rat. Apart from structural differences, the cellular composition of specific nuclei does not differ distinctly. It can suggest that their intrinsic and extrinsic connections might be similar and the role and function of them is maintained (with few exceptions) through the phylogeny