**Author details**

*Neuroprotection - New Approaches and Prospects*

*basolateral part; DLP, dorsolateral part; DMP, dorsomedial part.*

attached to large EDCs or weakly or moderately labeled PC cells. Such a neuroglial/ microglial construction corresponds to the established model of the intercellular relationships, in which glial cells are the main source of hydrogen sulfide for neurons [20, 27]. The relationship with neurons is a prerequisite for the release of H2S from astrocytes and the increase in intracellular calcium in astrocytes [18]. H2S activates the transition potential A1 channels (TRPA1) of the transition receptor, leading to an influx of calcium and activation of astrocytes by transmitting calcium waves after neuronal activation [37]. Further, D-serine is released from astrocytes, which subsequently activates the NMDA receptors [3]. Thus, the neuron-glial relationships were identified in CCb and granular eminences of the intact trout, in which H2S is very likely to be released from the astrocyte-like cells with subsequent activation of the NMDA receptors in neurons. Such features of organization of the H2S-producing cell complexes in trout correspond to physiological principles established in a mammalian model, according to which the astrocyte-like cells in the fish cerebellum regulate the amount of glutamate produced and its reuptake, preventing the excitotoxicity effects and providing the effective conditions for neurotransmis-

*Density of CBS+ cells in the cerebellum of the intact trout* Oncorhynchus mykiss*. Ratio of Purkinje cells (PC) and eurydendroid cells (EDC) in different parts of the cerebellum (mean ± SD). BMP, basomedial part; BLP,* 

After UEI in the trout cerebellum, the number of the CBS+ cells in ML increases dramatically, indicating a sharp activation of the ATP-dependent processes in this area. Along with the increase in the number of immunopositive cells, the number of the cellular CBS+ clusters also increases, both in the surface and deeper parts of ML. There is a reactivation of numerous neurogenic niches, with patterns of the neuron/glial/microglial colocation detected not only in GrL but also in ML. In ML, we found CBS+ fibers, which are absent in intact animals. In the neuron-glial complexes, glial cells are very intensely labeled, which indicates an increase in the CBS activity. We believe that this increase in the number of the CBS+ cells is due to the oxidative stress and the accumulation of ROS, which are neutralized by hydrogen sulfide. The sources of ROS generation in cell include mitochondria, superoxide-producing enzymes, such as xanthine oxide, NADPH oxidase, and hydrogen peroxide-producing enzymes, such as superoxide dismutase [12, 13]. ROS acceptors include antioxidants, such as glutathione, as well as enzymes superoxide dismutase and catalase. The modulation of ion channels and inflammatory and antioxidant transcription factors using H2S after UEI may play a protective role in reducing edema and inflammation [20, 29, 30]. Similar effects have been reported

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sion [2, 3].

**Figure 5.**

Evgeniya V. Pushchina1,2\*, Anatoly A. Varaksin1 and Dmitry K. Obukhov3

1 Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok, Russia

2 Bogomolets Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine

3 St. Petersburg State University, St. Petersburg, Russia

\*Address all correspondence to: puschina@mail.ru

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
