Minocycline but not valproic acid influence the density of NogoA-immunoreactive neurons in the hilus of the dentate gyrus of the rats subjected to intracerebral haematoma

Intracerebral haemorrhage is a devastating neurological disease with high mortality rate and poor prognosis. The most prominent manifestation of the disease arethe movement disorders, but many patients also suffer from cognitive impairment. Taking into account vulnerability of the neurons located within the hilus of the dentate gyrus (HDG) to many brain insults we decided to study the effectof experimentally induced intracerebral haematoma on density of neurons expressing NogoA protein in HDG. In addition, we studied how administration of valproic acid and minocycline, the two drugs generally believed to be neuroprotective agents, influences the density of these neurons. Our study revealed that 4 weeks after intracerebral haematoma induction, minocycline and valproic acid treatment increased the densities of NogoA-ir neurons in the hilus of contralateral dentate gyrus once the data were compared to ipsilateral hemispheres within the same group. The analysis of contralateral hemisphere data, however, revealed increased densities of NogoA-positive neurons in haematoma and valproic acidtreated animals when compared to contralateral hemispheres of control animals.The administration of minocycline was, however, able to alleviate this increase.These changes may influence the haematoma-induced reorganisation of neuronal circuitries in the dentate gyrus

The technique of inhalation anaethesia in experimental investigation in the rat

The rat is the most frequently used animal in scientific inquiry conducted for the purpose of advancing basic knowledge that may lead to an improvement in the results of treatment. Understanding of the pharmacological properties of inhalation anaesthetics, in combination with monitoring of their concentration in the inspired and end-tidal gas, together provide safe and precise control of the depth of the anaesthesia. However, accurate application of the inhalation method of anaesthesia requires special equipment for the delivery and effective scavenging of inhalation anaesthetics

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

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

Apoptosis in the course of experimetal intracerebral haemorrhage in the rat

Intracerebral haematoma was produced in 25 adult rats by infusion of 100 µl of autologous blood into the striatum. The animals’ brains were removed at 1, 3, 7, 14 and 21 days after production of the haematoma. The TUNEL method was used to detect DNA fragmentation and TUNEL-positive cells were qualified. TUNEL-positive cells were already found on the first day of observation and were present for three weeks after haematoma production. These results provide evidence that programmed cell death is associated with intracerebral haemorrhage

The piriform cortex and the endopiriform nucleus in the rat reveal generally similar pattern of connections

The afferent and efferent connections of the piriform cortex and the endopiriform nucleus in the rat were studied by the method of axonal transport of two fluorescent tracers: Fluoro-Gold and Fluoro-Ruby. The results indicate that both structures possess not only the connections with the olfactory system, but also the reciprocal connections with the limbic system (entorhinal cortex, amygdaloid body), thalamus (mediodorsal and midline nuclei), extrapyramidal system (ventral part of the nucleus accumbens). The topographic differences in the organisation of the association connections between the anterior and posterior parts of the piriform cortex are reported. Additionally, the reciprocal and relatively numerous connections between the endopiriformis nucleus and the piriform cortex may result in their modulatory function, which in some pathological circumstances may have a critical significance in epileptogenesis

Role of brain-derived neurotrophic factor in shaping the behavioural response to environmental stressors

Brain-derived neurotrophic factor (BDNF) is an important neurotrophin involved in an integration of the brain activity in physiological and pathological conditions, with formation of a short- and long-term functional and structural neuroplasticity. This process proceeds, with a changeable dynamics, in the subsequent stages of ontogenesis. In addition to many other functions in the central nervous system, BDNF is also involved in shaping a response to stress stimuli in the form of precisely adjusted behavioural reactions involving the limbic system, and the endocrine system with stimulation of the hypothalamic-pituitary-adrenal axis (HPA). Although almost every stressor increases the activity of the HPA, the neuronal response to it can vary substantially. This may be due to involvement of different neurotransmitter pathways, neuromodulators and neurohormones, as well as changes in gene expression. It is widely accepted that BDNF synthesis and secretion are modulated by stress. Furthermore, age is an important factor influencing the BDNF expression in response to different stressors. In this work, we focused on the analysis of the role of mild stressful stimuli, which commonly occur in the natural environment, on changes in BDNF expression at various stages of ontogenetic development. Although, the presented data comes from animal studies, probably similar mechanisms of stress regulation are also present in humans. This comprehensive review shows that the influence of stressors on the BDNF expression depends on many factors, including a type and duration of a stressor, time of neurotrophin detection, animal’s resistance to stress, brain area, and genotypic characteristics of an individual. A more detailed understanding of the mechanisms shaping stress reactions, including the role of BDNF, may be of both theoretical and practical importance, allowing designing more effective strategies for preventing and treating stress itself and the stress-related disorders

Neuroglia — development and role in physiological and pathophysiological processes

The dynamic development of studies on neuroglia in recent years indicates its previously underestimated role in maintaining proper brain function, both in physiological and pathological conditions. The use of modern research methods such as single-cell techniques as well as in vivo and in vitro models enriched the state of our knowledge. The most important issues regarding the maturation and development of neuroglia include cooperation between glial cell groups and with neurons in neurogenesis, neuroregeneration, (re)myelination and how the early developmental roles of glia contribute to nervous system dysfunction in neurodevelopmental and neurodegenerative disorders. There is still growing evidence emphasizing the importance of astroglia in maintaining the brain physiological homeostasis, regulation of immune response, cerebral blood flow, and involvement in the reactive neurogliosis, precisely adapted to the nature of pathological stimulus and the depth of tissue damage. The important issues related to the function of oligodendrocytes include explanation of the mechanisms of interaction between the glial cells and myelinated axons, important not only in myelination, but also in development of cognitive processes and memory. Further studies are required for understanding the mechanisms of demyelination occurring in several central nervous system (CNS) diseases. An interesting area of research is related with explanation on the NG2 glia function, characterized by significant proliferative potential and ability to differentiate in both in physiological conditions and in pathology, as well as the presence of synaptic neural glial connections, which are especially numerous during development. The increasing knowledge of microglia comprise the presence of specialised subsets of microglia, their role the myelination process and neurovascular unit functioning. We are only beginning to understand how microglia enter the brain and develop distinct functional states during ontogeny. This review summarises the current state of knowledge on the development and role in the CNS of different, heterogeneous cell populations defined by a common term neuroglia

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