http://sedici.unlp.edu.ar:80/handle/10915/140969 Thu, 12 Nov 2026 00:53:36 GMT 2026-11-12T00:53:36Z http://sedici.unlp.edu.ar:80/handle/10915/148577 Articulo Physiological Mini Reviews (PMR); vol. 3, no. 6 Enhanced proliferation, aberrant differentiation, and impaired ability to die are the prime reasons for abnormal tissue growth, which can eventually turn into uncontrolled expansion and invasion, characteristic of cancer. Ion channels contribute to virtually all basic cellular processes, including those for maintaining tissue homeostasis as proliferation, differentiation, and apoptosis (1). Changes in cell volume are crucial events during both cell proliferation and apoptosis and thus on tumor development and growth (2). Cell proliferation depends on an increased cell volume and cell shrinkage is a characteristic of apoptosis. Potassium, calcium, chloride channels and others are abnormally expressed in the membrane of tumor cells. By the regulation of membrane voltage, cell volume, Ca2+ signaling, cytosolic pH and cell cycle, they can adjust the cell proliferation and apoptosis. The specific blockade of ion channels may not only allow the dissection of the channel role in distinct physiologic processes, but because of the implication of them in tumor development, it may also offer an opportunity for the treatment of cancer. However, many ion channels are structurally similar to one another, and it has been notoriously difficult to obtain specific blockers for any given channel, thus it is essential to generate more potent and specific inhibitors of ion channels before using them in human therapeutics. Tue, 01 Jul 2008 00:00:00 GMT http://sedici.unlp.edu.ar:80/handle/10915/148577 2008-07-01T00:00:00Z Enhanced proliferation, aberrant differentiation, and impaired ability to die are the prime reasons for abnormal tissue growth, which can eventually turn into uncontrolled expansion and invasion, characteristic of cancer. Ion channels contribute to virtually all basic cellular processes, including those for maintaining tissue homeostasis as proliferation, differentiation, and apoptosis (1). Changes in cell volume are crucial events during both cell proliferation and apoptosis and thus on tumor development and growth (2). Cell proliferation depends on an increased cell volume and cell shrinkage is a characteristic of apoptosis. Potassium, calcium, chloride channels and others are abnormally expressed in the membrane of tumor cells. By the regulation of membrane voltage, cell volume, Ca2+ signaling, cytosolic pH and cell cycle, they can adjust the cell proliferation and apoptosis. The specific blockade of ion channels may not only allow the dissection of the channel role in distinct physiologic processes, but because of the implication of them in tumor development, it may also offer an opportunity for the treatment of cancer. However, many ion channels are structurally similar to one another, and it has been notoriously difficult to obtain specific blockers for any given channel, thus it is essential to generate more potent and specific inhibitors of ion channels before using them in human therapeutics. http://sedici.unlp.edu.ar:80/handle/10915/148576 Articulo Physiological Mini Reviews (PMR); vol. 3, no. 5 Gap-junctional channels communicate adjacent cells electrically and metabolically. They are formed by 4-transmembrane helix proteins called connexins; six connexins form a connexon (or gap-junctional hemichannel) and two of these, one from each neighboring cell, dock head-to-head to form the gap-junctional channel. The permeability of gapjunctional channels is regulated by voltage, intracellular calcium activity, intracellular pH and phosphorylation by various kinases. This review focuses on the mechanism of the regulation of connexin 43 by protein kinase C. We discuss results obtained largely from studies of hemichannels that demonstrate that the channel pore is narrowed down, but not closed, by protein kinase C-mediated phosphorylation of a single site, serine 368, located 14 residues away from the C-terminal end of connexin 43. The effect of protein kinase C involves a large conformational change of the protein and requires phosphorylation of all six subunits. The precise mechanism of the decrease in pore cross-sectional area has not been established. Thu, 01 May 2008 00:00:00 GMT http://sedici.unlp.edu.ar:80/handle/10915/148576 2008-05-01T00:00:00Z Gap-junctional channels communicate adjacent cells electrically and metabolically. They are formed by 4-transmembrane helix proteins called connexins; six connexins form a connexon (or gap-junctional hemichannel) and two of these, one from each neighboring cell, dock head-to-head to form the gap-junctional channel. The permeability of gapjunctional channels is regulated by voltage, intracellular calcium activity, intracellular pH and phosphorylation by various kinases. This review focuses on the mechanism of the regulation of connexin 43 by protein kinase C. We discuss results obtained largely from studies of hemichannels that demonstrate that the channel pore is narrowed down, but not closed, by protein kinase C-mediated phosphorylation of a single site, serine 368, located 14 residues away from the C-terminal end of connexin 43. The effect of protein kinase C involves a large conformational change of the protein and requires phosphorylation of all six subunits. The precise mechanism of the decrease in pore cross-sectional area has not been established. http://sedici.unlp.edu.ar:80/handle/10915/148575 Articulo Physiological Mini Reviews (PMR); vol. 3, no. 4 TRP is the most recently discovered family of ion channels and display the largest structure and function diversity among ion channels. Most TRP channels are key elements in sensory cells, where they are involved in the response to a broad range of external stimuli such as light, sound, chemicals, temperature and touch. In addition, cells detect changes in their local environment, like osmolarity and oxidative stress, by means of TRP channels. They have been found in eukaryotes like yeasts, worms, insects, fishes, birds, and mammals. In mammals, they are present in a wide range of organs and cells including central and peripheral nervous system. TRP channels were discovered in Drosophila photoreceptors, in a mutant that elicits a transient rather than maintained receptor potential in response to a sustained light stimulus. For this reason, this gene was termed transient receptor potential or trp. This mutation causes a ~10-fold reduction in the light induced Ca2+ influx to the photoreceptor (3, 6). Sat, 01 Mar 2008 00:00:00 GMT http://sedici.unlp.edu.ar:80/handle/10915/148575 2008-03-01T00:00:00Z TRP is the most recently discovered family of ion channels and display the largest structure and function diversity among ion channels. Most TRP channels are key elements in sensory cells, where they are involved in the response to a broad range of external stimuli such as light, sound, chemicals, temperature and touch. In addition, cells detect changes in their local environment, like osmolarity and oxidative stress, by means of TRP channels. They have been found in eukaryotes like yeasts, worms, insects, fishes, birds, and mammals. In mammals, they are present in a wide range of organs and cells including central and peripheral nervous system. TRP channels were discovered in Drosophila photoreceptors, in a mutant that elicits a transient rather than maintained receptor potential in response to a sustained light stimulus. For this reason, this gene was termed transient receptor potential or trp. This mutation causes a ~10-fold reduction in the light induced Ca2+ influx to the photoreceptor (3, 6). http://sedici.unlp.edu.ar:80/handle/10915/148574 Articulo Physiological Mini Reviews (PMR); vol. 3, no. 3 The physiological importance of the kidneys in the long-term control of extracellular volume and arterial pressure has been demonstrated in studies showing that an alteration of renal function leads to the development of hypertension and other cardiovascular dysfunctions (1-4). It has also been proposed that the development of hypertension may be secondary to an altered nephron endowment during the nephrogenic period (3,4). A cause-effect link between nephron number at birth and hypertension has been proposed in clinical and experimental studies showing that essential hypertensive patients have a reduced nephron number (3-6), and that the alteration of nephrogenesis leads to the development of hypertension during the adult life (3,4,7-10). A deficient nephrogenesis has been observed in offspring of pregnant mothers taking a low protein diet, or treated with either corticoids or a cyclooxygenase-2 (COX-2) inhibitor (3,4). The renin-angiotensin system (RAS) seems to play an important role in the regulation of nephrogenesis because its activity is reduced in these situations (3,4), and it is known that angiotensin II (Ang II) is involved in regulating renal growth and differentiation (11). The role of Ang II in renal development has been confirmed in studies demonstrating an elevation of all RAS components during the nephrogenic period and showing that the administration of either a converting enzyme inhibitor or an Ang II AT1 receptor antagonist during this period leads to a significant reduction in nephron number and an alteration of the normal kidney structure (7,8). Tue, 01 Jan 2008 00:00:00 GMT http://sedici.unlp.edu.ar:80/handle/10915/148574 2008-01-01T00:00:00Z The physiological importance of the kidneys in the long-term control of extracellular volume and arterial pressure has been demonstrated in studies showing that an alteration of renal function leads to the development of hypertension and other cardiovascular dysfunctions (1-4). It has also been proposed that the development of hypertension may be secondary to an altered nephron endowment during the nephrogenic period (3,4). A cause-effect link between nephron number at birth and hypertension has been proposed in clinical and experimental studies showing that essential hypertensive patients have a reduced nephron number (3-6), and that the alteration of nephrogenesis leads to the development of hypertension during the adult life (3,4,7-10). A deficient nephrogenesis has been observed in offspring of pregnant mothers taking a low protein diet, or treated with either corticoids or a cyclooxygenase-2 (COX-2) inhibitor (3,4). The renin-angiotensin system (RAS) seems to play an important role in the regulation of nephrogenesis because its activity is reduced in these situations (3,4), and it is known that angiotensin II (Ang II) is involved in regulating renal growth and differentiation (11). The role of Ang II in renal development has been confirmed in studies demonstrating an elevation of all RAS components during the nephrogenic period and showing that the administration of either a converting enzyme inhibitor or an Ang II AT1 receptor antagonist during this period leads to a significant reduction in nephron number and an alteration of the normal kidney structure (7,8). http://sedici.unlp.edu.ar:80/handle/10915/148572 Articulo Physiological Mini Reviews (PMR); vol. 3, no. 2 PCT is the main responsible for bulk reabsorption of solutes and volume in the nephron. Almost 80% of the glomerular filtrate is reabsorbed from the lumen of the PCT through the peritubular capillaries. Considering an individual of 70 Kg this amounts up to 140L of water and almost 0.5 Kg of Na+ reabsorbed per day; almost three times the total body water content and ten times the total body Na content. The whole process of Na+ reabsorption can be divided in three sequential steps: the first one driven mostly by the electrochemical gradient for sodium at the apical membrane, the second, which is pivotal and responsible for O2 consumption of the kidney, involves the activity of the Na+-K+ ATPase located at the basolateral membrane which extrudes Na+ out of the cytosol , and the third one, due to solvent drag, occurring through the endothelial cells of capillaries, consequence of the Starling’s equilibrium forces between the peritubular interstitium and the peritubular capillary lumen. Indeed, as a result of glomerular filtration the balance between oncotic pressure and hydrostatic pressure favors the net flow of volume from the interstitium through the capillary including the solutes present in the reabsorbed fluid. Thu, 01 Nov 2007 00:00:00 GMT http://sedici.unlp.edu.ar:80/handle/10915/148572 2007-11-01T00:00:00Z PCT is the main responsible for bulk reabsorption of solutes and volume in the nephron. Almost 80% of the glomerular filtrate is reabsorbed from the lumen of the PCT through the peritubular capillaries. Considering an individual of 70 Kg this amounts up to 140L of water and almost 0.5 Kg of Na+ reabsorbed per day; almost three times the total body water content and ten times the total body Na content. The whole process of Na+ reabsorption can be divided in three sequential steps: the first one driven mostly by the electrochemical gradient for sodium at the apical membrane, the second, which is pivotal and responsible for O2 consumption of the kidney, involves the activity of the Na+-K+ ATPase located at the basolateral membrane which extrudes Na+ out of the cytosol , and the third one, due to solvent drag, occurring through the endothelial cells of capillaries, consequence of the Starling’s equilibrium forces between the peritubular interstitium and the peritubular capillary lumen. Indeed, as a result of glomerular filtration the balance between oncotic pressure and hydrostatic pressure favors the net flow of volume from the interstitium through the capillary including the solutes present in the reabsorbed fluid. http://sedici.unlp.edu.ar:80/handle/10915/140971 Articulo Physiological Mini Reviews (PMR); vol. 3, no. 1 The success of any species depends on its reproductive efficiency. Sexual procreation is initiated by interactions between a sperm and an egg leading to fertilization. The fertilized egg (embryo) undergoes several mitotic cell divisions, ultimately producing the blastocyst. The nurturing of an offspring within the body and production of a live birth is an enduring task, requiring safeguard regulatory systems at various critical steps. At the moment, there is still a significant knowledge gap in understanding the mechanisms by which a successful pregnancy is achieved. It is difficult to define the hierarchical landscape of the molecular pathways during human pregnancy, because of experimental difficulties and ethical restrictions on research with human embryos. It is hoped that experiments on mice and other animal models that bear certain reproductive similarities with humans combined with those feasible experiments in humans would generate meaningful information to address this critical issue. A deeper insight into these processes will help to generate new ideas and concepts for improving fertility and pregnancy-associated health issues in humans. During the last years, several studies have provided evidence that lipid mediators are important signaling molecules in coordinating a series of events during pregnancy. Increasing evidence points toward the pathophysiological significance of endocannabinoids, a group of bioactive lipid-signaling molecules, in both female and male fertility. Mon, 01 Jan 2007 00:00:00 GMT http://sedici.unlp.edu.ar:80/handle/10915/140971 2007-01-01T00:00:00Z The success of any species depends on its reproductive efficiency. Sexual procreation is initiated by interactions between a sperm and an egg leading to fertilization. The fertilized egg (embryo) undergoes several mitotic cell divisions, ultimately producing the blastocyst. The nurturing of an offspring within the body and production of a live birth is an enduring task, requiring safeguard regulatory systems at various critical steps. At the moment, there is still a significant knowledge gap in understanding the mechanisms by which a successful pregnancy is achieved. It is difficult to define the hierarchical landscape of the molecular pathways during human pregnancy, because of experimental difficulties and ethical restrictions on research with human embryos. It is hoped that experiments on mice and other animal models that bear certain reproductive similarities with humans combined with those feasible experiments in humans would generate meaningful information to address this critical issue. A deeper insight into these processes will help to generate new ideas and concepts for improving fertility and pregnancy-associated health issues in humans. During the last years, several studies have provided evidence that lipid mediators are important signaling molecules in coordinating a series of events during pregnancy. Increasing evidence points toward the pathophysiological significance of endocannabinoids, a group of bioactive lipid-signaling molecules, in both female and male fertility.