The article reflects the current position of the issue of morphologies of the pathways of intercellular circulation in the brain. There are covered main, known at present time, data on the features of the exchange between the spinal fluid and intercellular fluid, the ways of elimination of the intertissued fluid of the brain through the so-called “glymphatic system”, its components: transarterial, transvenous, and transglial ways of intercellular fluid outflow from brain tissue. It also raises the question of the role of glia namely astrocytes and ependymocytes – as the main cells forming the haemato-encephalic barrier and participating in the intercellular circulation.

No abstract

Studies of the nervous system today are quite relevant and important. There are a large number of methods of studying and researching the brain, among which the histological method is widely used. Despite the variety of methods, in the possible practical application of histological examination of the central nervous system and brain in particular there are problems encountered by researchers: the complexity of the method, a large number of conventions to consider when working with nerve tissue, methods of fixation. Among other research methods, there is a group of histological methods, united by a common feature – in vivo staining of the nervous system, among which there is also a method of in vivo staining with methylene blue. The aim of the study was to establish the morphological features of the structure of the intercellular fluid circulation of the brain in experimental animals. The article describes a new method of injectable in vivo staining of the brains of laboratory animals with methylene blue. It is relevant for studying the morphology of the intercellular fluid circulation of the brain and the study of the structure of the microcirculatory tract. In our work it is offered to combine already known methods of perfusion fixation and a technique of supravital staining with methylene blue. Since most scientific studies of the brain use conventional research methods without a comprehensive study of the entire microcirculatory tract and intercellular fluid circulation, there is a need for more detailed study of the histological structure and topography of microcirculatory brain complexes to establish their normal structure. The results of the study confirm the researchers' observation that methylene blue has a high affinity for nerve fibers in the brain. In addition, it is obvious that the additional use of formalin as a solvent increases the resistance of methylene blue to leaching and the ability to stain the structures of the microcirculatory tract. In addition, the lifetime application of this technique allows you to visualize the morphological features of the microcirculation pathways of the intercellular fluid of the brain, Virchow-Robin space and capillary walls.