Melatonin promotes and synchronizes protein synthesis in hepatocyte culture from old rats

The effect of 1 to 1000 nM melatonin was studied on daily cultures of rat hepatocytes on slides in serum-free medium. The minimum melatonin concentration (1 nM) proved to synchronize protein synthesis in asynchronous sparse cultures of hepatocytes from rats of different age, and a circahoralian rhythm of protein synthesis was revealed in them. In dense weekly synchronous hepatocytes from old rats (2.5 years old with the weight of about 600 g), melatonin improved cell synchronization to the level of young animals. Melatonin treatment increased the mean rate of protein synthesis in rats of different age.     

Signaling factors of self-organization of protein synthesis rhythm in hepatocyte cultures—gangliosides and catecholamines function independently

Considering the data on the low level of self-organization (self-synchronization) of protein synthesis rhythm in aging, we studied the possible interference of the signaling factors of self-organization, gangliosides and catecholamines, as well as catecholamine reception. Experiments were carried out on primary cultures of rat hepatocytes on slides. Inhibited ganglioside synthesis did not prevent the organization of protein synthesis rhythm by the α-adrenomimetic agent phenylephrine. Upon the blockade of α-receptors by prazosin, the protein synthesis rhythm was observed after the exposure to gangliosides. α-Adrenolytic agents prazosin and benoxathian abolished the synchronizing effect of the β-adrenomimetic isoproterenol. A mixture of α-and β-adrenomimetic agents inhibited the protein synthesis rhythm-organizing effect of noradrenaline. Thus, the signaling molecules of self-organization of protein synthesis function independently via specific receptors.     

Effect of Transcranial Magnetic Stimulation on Short- and Long-Term Memory in Healthy Subjects and Patients with Parkinson’s Disease

The effect of transcranial magnetic stimulation (TMS) of the right and the left frontotemporal areas on the short- and long-term verbal memory was studied in healthy subjects and patients with Parkinson’s disease. TMS with a magnetic induction of more than 1.2 T at 10 Hz was found to affect the short-term memory when applied to the left frontotemporal area and to have no significant effect on this type of memory when applied to the right frontotemporal area. In healthy subjects, TMS applied to the left or the right hemisphere did not affect the long-term memory. However, in patients with Parkinson’s disease, significant changes in the long-term memory were observed upon TMS of either the left or the right hemisphere. The effect was more evident on TMS of the right hemisphere.__________Translated from Fiziologiya Cheloveka, Vol. 31, No. 4, 2005, pp. 33–36.Original Russian Text Copyright © 2005 by Gimranov, Mal’tseva.     

Effects of Sodium Selenite and Dithiothreitol on Expression of Endoplasmic Reticulum Selenoproteins and Apoptosis Markers in MSF7 Breast Adenocarcinoma Cells

Molecular Biology - The endoplasmic reticulum (ER) stress inducers dithiothreitol (DTT) and sodium selenite (SS) were tested for effect on expression of ER selenoproteins and apoptosis markers in...