Changes in the Frequency of Rhythmic Excitation of Retzius Cells during Thermal Stimulation of Leech Skin

Thermal stimulation of various parts of the skin in Hirudo medicinalis increases the frequency of spontaneous rhythmic excitation of Retzius neurons in leech ganglia. It was shown that the frequency of spontaneous rhythmic excitation of Retzius cells in the segmental ganglion increases only in response to thermal stimulation and returns to initial values upon cooling. This effect was also detected in neurons that are not directly connected by nerve fibers with the particular skin area. Changes in the frequency of spontaneous rhythmic excitation of Retzius cells in the segmental ganglion were observed during thermal stimulation of not only leech body, but also of the head and caudal suckers. These changes in spontaneous rhythmic excitation of Retzius cells in the segmental ganglion during thermal stimulation were observed in Hirudo medicinalis, but not in Macrobdella decora.

The Effect of Resveratrol on the Composition and State of Lipids and the Activity of Phospholipase A2 During the Excitation and Regeneration of Somatic Nerves

It has been shown that in the somatic nerve's lipids, both during excitation and transection, changes occur with the composition of individual phospholipids and in phospholipids fatty acids, which changes the phase state of the myelin and nerve fiber axolemma lipid bilayer. A main contribution in the nerve degenerative processes is dependent on the composition phospholipid's fatty acid changes during the activation of both Ca²⁺-dependent and Ca²⁺-independent phospholipase A₂ forms. At the same time, we studded changes in phosphoinisitol (PI) and diacylglycerol (DAG), which depend on the phosphoinositide cycle function during nerve excitation and degeneration processes. It was found that myelin lipids and nerve fiber axolemmas are involved not only in the functioning of the peripheral nerves, but also the pathological processes underlying deep functional and structural disorders. The effect of resveratrol on regeneration processes in the damaged rat sciatic nerve has also been investigated.

Direct participation of starburst amacrine cells in spontaneous rhythmic activities in the developing mammalian retina

Spontaneous, rhythmic waves of excitation in the developing mammalian retina play a critical role in the formation of precise neuronal connectivity in the visual system. However, it is not known what circuits in the retina are responsible for the production of these waves. Using patch-clamp recordings in the whole-mount neonatal rabbit retina, this study reports that the displaced starburst amacrine cell, a unique cholinergic interneuron in the ganglion cell layer of the retina, undergoes rhythmic bursts of membrane depolarization with a frequency and duration similar to those of spontaneous retinal waves. Simultaneous patch-clamp recordings from pairs of neighboring starburst and ganglion cells show that the rhythmic activity in starburst cells is closely correlated with that in ganglion cells, and that the excitation in both cell types is most likely driven by synaptic input. However, in contrast to ganglion cells, displaced starburst cells usually do not generate spontaneous somatic action potentials. Instead, they seem to use subthreshold potentials (at least at the soma) to mediate the rhythmic excitation. The results suggest that acetylcholine is likely released rhythmically in the developing retina. Thus, starburst amacrine cells form the first identified network of retinal interneurons that directly participate in spontaneous rhythmic activities in the developing retina.