The rationale for the topical application of capsaicin and other vanilloids in the treatment of pain is that such compounds selectively excite and subsequently desensitize nociceptive neurons. This desensitization is triggered by the activation of vanilloid receptors (TRPV1), which leads to an elevation in intracellular free Ca2+ levels. Depending on the vanilloid concentration and duration of exposure, the Ca2+ influx via TRPV1 desensitizes the channels themselves, which may represent not only a feedback mechanism protecting the cell from toxic Ca2+ overload, but also likely contributes to the analgesic effects of capsaicin. This review summarizes the current state of knowledge concerning the mechanisms that underlie the acute capsaicin-induced Ca2+-dependent desensitization of TRPV1 channels and explores to what extent they may contribute to capsaicin-induced analgesia. In view of the polymodal nature of TRPV1, we illustrate how the channels behave in their desensitized state when activated by other stimuli such as noxious heat or depolarizing voltages. We also show that the desensitized channel can be strongly reactivated by capsaicin at concentrations higher than those previously used to desensitize it. We provide a possible explanation for a high incidence of adverse effects of topical capsaicin and point to a need for more accurate clinical criteria for employing it as a reliable remedy., L. Vyklický, K. Nováková-Toušová, J. Benedikt, A. Samad, F. Touška, V. Vlachová., and Obsahuje bibliografii a bibliografické odkazy
In the mammalian neocortex, the calcium-binding protein calretinin is expressed in a subset of cortical interneurons. In the recent years, research on interneurons is one of the most rapidly growing fields in neuroscience. This review summarizes the actual knowledge of the functions of calretinin in neuronal homeostasis and particularly of the distribution, connectivity and physiological properties of calretinin expressing interneurons in the neocortex of rodents and primates, including humans. The possible neuroprotective role of calretinin and the presumed “resistance” of calretinin-expressing interneurons to various pathological processes are also discussed., F. Barinka, R. Druga., and Obsahuje bibliografii a bibliografické odkazy
Calsequestrin is the main calcium binding protein of the sarcoplasmic reticulum, serving as an important regulator of Ca 2+ . In mammalian muscles, it exis ts as a skeletal isoform found in fast- and slow-twitch skeletal muscles and a cardiac isoform expressed in the heart and slow-twitch muscles. Recently, many excellent reviews that summarised in great detail various aspects of the calsequestrin structure, localisation or function both in skeletal and cardiac muscle have appeared. The present review focuses on skeletal muscle: information on cardiac tissue is given, where differences between both tissues are functionally important. The article reviews the known multiple roles of calsequestrin including pathology in order to introduce this topic to the broader scientific community and to stimulate an interest in this protein. Newly we describe our results on the effect of thyroid hormones on skeletal and cardiac calsequestrin expression and discuss them in the context of available literary data on this topic., P. Novák, T. Soukup., and Obsahuje bibliografii a bibliografické odkazy
Kdyby nebylo popularizátorů, pak bychom kromě úzké vědecké komunity věděli o vědě, vědcích a smyslu jejich práce velmi málo. Pokud sem tam uniknou mimo jejich společnost nějaké informace o výzkumech a pokusech zdařených i nezdařených, bývají strohé a laikům nesrozumitelné. Tudíž nevědcům je třeba je ozřejmit, jaksi polidštit. A zde nastupují populátoři vědy, lidé vládnoucí mistrnou schopností přenést do veřejnosti - ne úplně laické - to, nač vědci myslí, co tvoří a vůbec, čím se zabývají a jací jsou. Pokud nahlédneme do dějin přírodních věd, zjistíme, že jako první byla popularizována astronomie. Stalo se tak především zásluhou francouzského astronoma Nicolase Camille Flammariona., This contribution describes the life and the work of French astronomer and writer Camille Flammarion. He is well known as a pioneer in science (esp. astronomy) popularization. The introductory part of this article sheds light on Flammarion‘s professional career in the Paris Observatory and in the Bureau of Measures. The central part of the article overviews Flammarion‘s popularization work, including writing books, giving public lectures, editing several journals, and so on. Flammarion‘s views on a calendar reformation are also discussed. The article ends with a list of Flammarion‘s publications, including their Czech editions., František Jáchim., and Obsahuje seznam literatury
Safranal and crocin are biologically active compounds isolated from Crocus sativus L., commonly known as saffron. Clinical trials confirm that saffron has antidepressant effect, thus being a potential valuable alternative in the treatment of depression. The aim of the present study was to determine, whether systemic administration of safranal and crocin can influence the metabolic activity of CYP3A, CYP2C11, CYP2B, and CYP2A in rat liver microsomes (RLM). The experiments were carried out on male Wistar albino rats intragastrically administered with safranal (4, 20, and 100 mg/kg/day) or with intraperitoneal injections of crocin (4, 20, and 100 mg/kg/day). Our results demonstrate the ability of safranal and crocin to increase the total protein content and to change the metabolic activity of several CYP enzymes assessed as CYP specific hydroxylations of testosterone in RLM. Crocin significantly decreased the metabolic activity of all selected CYP enzymes, while safranal significantly increased the metabolic activity of CYP2B, CYP2C11 and CYP3A enzymes. Therefore, both substances could increase the risk of interactions with co-administered substances metabolized by cytochrome P450 enzymes., G. Dovrtělová, K. Nosková, J. Juřica, M. Turjap, O. Zendulka., and Obsahuje bibliografii