PECULIARITIES OF CENTRAL AND PERIPHERAL CONTROL OF THE SPINAL CORD FLEXOR AND EXTENSOR MOTOR NEURONS ACTIVITY

Mechanisms of development of the hind limb nerve crush are intensively studied. However, the peculiarity of their restoraton has not been revealed en masse yet. As the appropriate experimental data are lacking, the comparative analysis of degree and velocity of flexor and extensor nerves regeneration and their selective central and peripheral control is of interest. For this purpose criteria of differentiation of spinal cord (SC) extensor and flexor motor neurons (MN) were studied by means of stimulation of corresponding nerves and brain special centers of their regulation. For differentiation of the latter, joint stimulation of central and peripheral structures, which control the flexor and extensor muscles activity (pyramidal tract, nucleus ruber-RMC - suprasegmental flexor center, nucleus Deiters' - supraspinal extensor center, flexor n. gastrocnemius and extensor n. peroneus communis), in different correlations were tested. The high frequency stimulation was used to cause tetanic (TP,TD) and posttetanic (PTP, PTD) potentiation and depression manifestations of different intensity and duration. In ideal cases the adequate activation of structures took place providing the excitation of some MN with reciprocal inhibition of antagonists. More frequently the clear-cut differentiation succeeded owing to reciprocal involvement of central and peripheral structures separately. The cases of uni- and differently directed effects of central and peripheral structures were often revealed. However, cases of unidirectional action of both central and peripheral structures, providing the synergism instead the antagonism remain to be "casual". It is proposed to use for MNs differentiation only cases of reciprocal correlation of antagonists and synergists, engaged in realization of unidirectional motor act (flexor or extensor), with corresponding inhibition of the antagonistic one. It appears optimal for MNs differentiation to use stimulation of structures mainly of central origin, in particular of the RMC and nucleus Deiters' with their reciprocal activation.