ОСОБЕННОСТИ РАСПРЕДЕЛЕНИЯ КАЛЬРЕТИНИН-ИММУНОПОЗИТИВНЫХ НЕЙРОНОВ В ПОЯСНИЧНОМ ОТДЕЛЕ СПИННОГО МОЗГА КОШКИ ( FELIS CATUS )

Abstract

The variety of neural networks of the central nervous system is determined by the heterogeneity of the neuron populations. Calcium-binding proteins can be used as markers of neurons of different morphotypes. One of the most common calcium-binding proteins in nervous system is calretinin. In the present work, using an indirect immunohistochemical method, calretinin-immunopositive neuronal populations of the lumbar segments of the cat spinal cord were marked. In the study we identified 19 morphotypes of neurons with strict segmental and laminar localization; an attempt was made to compare the proposed function of the neuron type with the available literature data. Among the identified morphotypes, three are localized in lamina I and correspond to neurons involved in the transmission of painful and temperature information. In lamina II, cells of the one morphotype were found, on which pain afferents converge. Three types of project neurons transmitting information from peripheral mechano- and nociceptors to supraspinal structures are presented in laminae III-IV. Laminae V-VI are characterized by functionally different neurons of five morphotypes: interneurons of the Clarke’s nuclei and a similar zone of the caudal lumbar segments, to which proprioceptive information converges; neurons on the lateral border between the white and gray matter, responding to painful and tactile signals; and two types of randomly distributed interneurons, projection or propriospinal neurons that receive heterogeneous afferent signals from muscle spindles. In laminae VII-VIII, two types of sympathetic preganglionic neurons (in the intermediolateral and intercalated nuclei), Renshaw's interneurons, and three types of differently sized multipolar cells were identified, the function of which is difficult to determine. No immunopositive neurons were found in lamina IX, represented by motoneuron pools. Around the central canal in lamina X, rare neurons are localized, the function for which, due to the small number of their morphological features, is not defined.