RESUMEN
We studied the effect of bovine brain gangliosides, individual ganglioside GM1, and melatonin on the rate of wound closure under in vitro conditions and the effect of melatonin on the rate of wound healing under in vivo conditions. It was shown that bovine brain gangliosides and melatonin reliably increased cell migration in the experimental wound model. This effect was detected when the cell cultures were treated with the test preparations after wound infliction and when the cultures of human keratinocytes were pretreated before wounding. Analysis of the effect of melatonin on the rate of wound healing in vivo showed that melatonin accelerated this process, especially at the middle stages corresponding to the proliferation phase (days 3-6 after surgery). Histological analysis revealed intensification of epidermal cell proliferation at the edges of the wound starting from day 4 after surgery.
Asunto(s)
Gangliósido G(M1)/farmacología , Queratinocitos/efectos de los fármacos , Melatonina/farmacología , Repitelización/efectos de los fármacos , Cicatrización de Heridas/efectos de los fármacos , Animales , Bovinos , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Piel/crecimiento & desarrolloRESUMEN
The kinetics of protein synthesis was investigated in primary cultures of hepatocytes from old rats in serum-free medium. The rats were fed mixed fodder supplemented with glutamic acid and then transferred to a regular mixed fodder. The amplitude of protein synthesis rhythm in hepatocytes isolated from these rats increased on average 2-fold in comparison with the rats not receiving glutamic acid supplement. Based on this indicator reflecting the degree of cell-cell interactions, the cells from old rats were not different from those of young rats. The effect was preserved for 3-4 days. These results are discussed in connection with our previous data on preservation of the effect of single administration of gangliosides, noradrenaline, serotonin, and other synchronizers on various cell populations. In contrast to the other investigated factors, glutamic acid is capable of penetrating the blood-brain barrier, which makes its effect possible not only in the case of hepatocytes and other non-brain cells, but also in neurons.
Asunto(s)
Comunicación Celular/efectos de los fármacos , Ácido Glutámico/farmacología , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Proteínas Quinasas/biosíntesis , Animales , Ácido Glutámico/administración & dosificación , Cinética , Ratas , Ratas WistarRESUMEN
Dense cultures of hepatocytes from old rats (~2 years old, body weight 530-610 g) are different from similar cultures of hepatocytes from young rats by the low amplitude of protein synthesis rhythm. Addition of glutamic acid (0.2, 0.4, or 0.6 mg/ml) into the culture medium with hepatocytes of old rats resulted in increase in the oscillation amplitudes of the protein synthesis rhythm to the level of young rats. A similar action of glutamic acid on the protein synthesis kinetics was observed in vivo after feeding old rats with glutamic acid. Inhibition of metabotropic receptors of glutamic acid with α-methyl-4-carboxyphenylglycine (0.01 mg/ml) abolished the effect of glutamic acid. The amplitude of oscillation of the protein synthesis rhythm in a cell population characterizes synchronization of individual oscillations caused by direct cell-cell communications. Hence, glutamic acid, acting as a receptor-dependent transmitter, enhanced direct cell-cell communications of hepatocytes that were decreased with aging. As differentiated from other known membrane signaling factors (gangliosides, norepinephrine, serotonin, dopamine), glutamic acid can penetrate into the brain and thus influence the communications and protein synthesis kinetics that are disturbed with aging not only in hepatocytes, but also in neurons.
Asunto(s)
Ácido Glutámico/farmacología , Biosíntesis de Proteínas/efectos de los fármacos , Envejecimiento/efectos de los fármacos , Animales , Comunicación Celular/efectos de los fármacos , Células Cultivadas , Senescencia Celular/efectos de los fármacos , Glicina/análogos & derivados , Glicina/farmacología , Hepatocitos/citología , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Cinética , Neuronas/metabolismo , Ratas , Ratas Wistar , Transducción de Señal/efectos de los fármacosRESUMEN
Primary cultures of rat hepatocytes were studied in serum-free media. Ultradian protein synthesis rhythm was used as a marker of cell synchronization in the population. Addition of glutamic acid (0.2 mg/ml) to the medium of nonsynchronous sparse cultures resulted in detection of a common protein synthesis rhythm, hence in synchronization of the cells. The antagonist of glutamic acid metabotropic receptors MCPG (0.01 mg/ml) added together with glutamic acid abolished the synchronization effect; in sparse cultures, no rhythm was detected. Feeding rats with glutamic acid (30 mg with food) resulted in protein synthesis rhythm in sparse cultures obtained from the rats. After feeding without glutamic acid, linear kinetics of protein synthesis was revealed. Thus, glutamic acid, a component of blood as a non-neural transmitter, can synchronize the activity of hepatocytes and can form common rhythm of protein synthesis in vitro and in vivo. This effect is realized via receptors. Mechanisms of cell-cell communication are discussed on analyzing effects of non-neural functions of neurotransmitters. Glutamic acid is used clinically in humans. Hence, a previously unknown function of this drug is revealed.
Asunto(s)
Ácido Glutámico/farmacología , Hepatocitos/metabolismo , Neurotransmisores/farmacología , Biosíntesis de Proteínas/efectos de los fármacos , Animales , Comunicación Celular/efectos de los fármacos , Células Cultivadas , Glicina/análogos & derivados , Glicina/farmacología , Hepatocitos/citología , Ratas , Ratas Wistar , Receptores de Glutamato Metabotrópico/agonistas , Receptores de Glutamato Metabotrópico/antagonistas & inhibidores , Receptores de Glutamato Metabotrópico/metabolismoRESUMEN
Melatonin administered to rat intraperitoneally organizes ultradian rhythm of protein synthesis in hepatocytes that persists for 1 day after exposure to the synchronizing signal. Hepatocytes were isolated 1 day after melatonin administration and cultured on coverslips in a serum-free medium. In 24 h in culture, the kinetics of protein synthesis was analyzed. In our previous experiments, we detected a rhythm in cells isolated in 1.5 h, but not in 3 days after melatonin administration to the rat. We have found that synchronization of oscillations of the protein synthesis intensity in vivo persists over 1 day after rat exposure to melatonin. Phenylephrine, an efficient synchronizer of protein synthesis in vitro, does not organize the rhythm in vivo.
Asunto(s)
Melatonina/administración & dosificación , Biosíntesis de Proteínas/efectos de los fármacos , Animales , Melatonina/farmacología , Ratas , Ratas WistarRESUMEN
Serotonin acts as antagonist of progesterone on amphibian oocytes. Serotonin antagonists inhibit maturation of starfish oocytes and stimulate or trigger maturation in amphibians. We propose that endogenous serotonin participates in the control of oocyte maturation.
Asunto(s)
Oocitos/fisiología , Antagonistas de la Serotonina/farmacología , Serotonina/farmacología , Adenina/análogos & derivados , Adenina/farmacología , Animales , Relación Dosis-Respuesta a Droga , Femenino , Cinética , Oocitos/citología , Oocitos/efectos de los fármacos , Progesterona/farmacología , Estaciones del Año , Estrellas de Mar , Xenopus laevisRESUMEN
In early embryos of eight starfish species both usual sensitivity and supersensitivity to cytotoxic neurochemicals have been found. This sensitivity is unaffected by the removal of the cell nucleus. In the starfish Aphelasterias japonica the supersensitivity in the embryos' red halves is higher and in embryos' white halves lower than in the whole embryos.
Asunto(s)
Oocitos/efectos de los fármacos , Psicotrópicos/farmacología , Estrellas de Mar/fisiología , Animales , División Celular/efectos de los fármacos , Embrión no Mamífero/efectos de los fármacos , Femenino , Ovario/citología , Agua de Mar , Estrellas de Mar/embriología , TemperaturaRESUMEN
From eggs and embryos of the sea urchin Strongylocentrotus intermedius two gangliosides, provisionally named G-1 and G-2, were isolated in the pure state. Both gangliosides contained glucose, N-glycoloylneuraminic acid and sphingosines in a 2:2:1 ratio; G-2 contained also a sulfate group, and yielded G-1 on desulfation. By periodate oxidation/borohydride reduction, permethylation analysis, neuraminidase degradation, analysis of the aldohexitol acetates and mass-spectrometry G-1 and G-2 were shown to have hitherto unknown structures: G-1 was identified as N-glycoloylneuraminosyl-(alpha 2 leads to 6)-glucosyl-(1 leads to 8)-N-glycoloylneuraminosyl-(2 leads to 6)-glucosyl-(1 leads to 1)-ceramide, and G-2 as sulfated G-1, carrying a sulfate ester group at C-8 of the terminal sialic acid. Antisera against the two gangliosides were prepared in rabbits by immunization with ganglioside G-1 or G-2. The specificity of the antisera was revealed by immunoelectrophoresis and immunodiffusion. The antisera did not react with bovine-brain and rat-liver gangliosides, with glucosylceramide and with various hydrolytic fragments of G-1 and G-2. The surface localization of the gangliosides in embryos incubated at different cell densities was studied by immunofluorescence microscopy. The intensity of the immunofluorescence was found to increase with decreasing cell density, indicating a different surface organization in sparse and dense embryos. In the sparse embryos immunofluorescence was seen mainly in the contact regions between the blastomers.
Asunto(s)
Embrión no Mamífero/análisis , Gangliósidos/análisis , Lípidos de la Membrana/análisis , Óvulo/análisis , Animales , Cerebrósidos/análisis , Ácidos Grasos/análisis , Femenino , Técnica del Anticuerpo Fluorescente , Cromatografía de Gases y Espectrometría de Masas , Hidroxiácidos/análisis , Inmunodifusión , Metilación , Erizos de MarRESUMEN
Two main gangliosides (G-1 and G-2) were isolated from eggs and embryos S. intermedius. They contain glucose, N-glucolylneuraminic acids, phytosphyngosine, fatty acids and alpha-hydroxy fatty acids. Molar ratios and sequence of these components are the same for both gangliosides, but G-2 contains sulphate residue which is attached to the terminal neuraminic acid. To obtain specific antisera rabbits were immunized by G-1 or G-2, which were mixed with bovine serum albumin and Freund's adjuvant. Both gangliosides possessed electrophoretic and antigenic heterogeneity. G-1 and G-2 gangliosides have common and individual antigenic determinants. Glucosylceramide of gangliosides is immunologically inactive. Individual antigenic specificity of the gangliosides depends on the presence of N-glycolylneuraminic acid (G-1) and SO3H-group (G-2). Egg gangliosides were demonstrated by immunofluorescence throughout the cell surface. After fertilization of immunofluorescent label was concentrated on one pole of the embryo only. During the development of specific fluorescence was again uniformly distributed at the blastomer surface. The most intense fluorescence was observed in the junction areas of the blastomers.