[Contractile Tone and Contraction as Important Physiological Properties of Terminals on the Processes of Living...

An attempt to summarize some static morphological renderings of reversible structural alterations of nervous processes, as well as receptor and synaptic terminals, to compare them with the mechanisms of actual transformation of living neurons and to find a common kinetic characteristic for these phenomena has been made. The contractile tone and contraction of processes of living isolated neurons are reported. The dependence of the direction of retraction on the localization of the adhesion site of the isolated cell has been detected. The retraction bulb has been identified as an indicator of all contractions of motor and sensory terminals, both alive and fixed. The process of transformation of growth cones into retraction bulbs has been investigated. The presence of mechanical tension in preterminals and interneuronal contacts has been demonstrated in vitro. Similarity of the kinetics of tissue receptor sensory terminals and growth cones has been detected during in vivo experiments. The kinetics of asynaptic dendrite contraction has been compared to the well-characterized structural variability of dendritic spines. The hypothesis of a common origin of the contractile tone of all nervous elements as one of the principal nonelectrophysiological properties of a neuron has been put forward.