Dexamethasone attenuates the modulatory effect of the insular cortex on the baroreflex in anesthetized rat.

The arterial baroreflex (BR) is an important neural mechanism for the stabilization of arterial pressure (AP). It is known that the insular cortex (IC) and other parts of the central autonomic network (CAN) are able to modulate the BR arc, altering baroreflex sensitivity (BRS). In addition, the sensitivity of the BR changes under the influence of hormones, in particular glucocorticoids (GCs).

Inhibition of contractions of nerve processes in calcium-free medium.

The possibility of blocking contractile activity of damaged neurites was studied on viable isolated neurons from Lymnaea stagnalis mollusks. Retraction was blocked in more than 80% cells plunged in Ringer's solution free from Ca(2+) or containing 20 mM CoCl(2). Nimodipine and nitrendipine significantly inhibited neurite contractions.

[Cytoplasmic syncytial interneuronal connection in molluscs].

The absolute criteria developed by the authors have been presented; they allow revealing cytoplasmic syncytial connections between processes of nerve cells in vivo and in vitro at the light microscopy level by using classical methods and time lapse videoshooting in the phase contrast. With aid of electron microscopy, metastable membrane contacts and their perforations, cytoplasmic syncytial interneuronal pores, and fusion of nerve processes are demonstrated. In the culture of isolated molluscan neurons, the process of formation of syncytial connection between processes of the same neuron or of different neurons is reproduced.

The question of the fusion of neuron processes.

The authors, whilst accepting the neuron theory, present data indicating the possibility that neuronal syncytia exist when myelin-coated ring-like structures form in the dendritic field, in nerve arcades close to neuron bodies, and on formation of thick, straight anastomoses between neuron bodies. Studies using computerized time-lapse videomicroscopy in cultures of isolated neurons demonstrated the mechanism by which these structures form. This report provides the first evidence of the time parameters of the fusion of the processes of a single live neuron; the fusion of fragments of an isolated glial-free fiber was demonstrated.

Syncytial coupling of neurons in tissue culture and early ontogenesis.

Computerized time-lapse video recording was used to detect the process of formation of syncytial couplings between the processes of different neurons in dissociated neuron cultures. These studies showed that once the processes of one neuron had formed connections with another neuron, death of the cell body (its trophic center) was not followed by Wallerian degeneration. Translocation of cytoplasmic varicosities along the branches of one neuron to another was observed over periods of several hours.