bluuebunny/crossref_metadata_2025 huggingface dataset:
Modulation of Transmitter Release by Action Potential Duration at the Hippocampal CA3-CA1 Synapse
Authors: Qian Jing , Saggau Peter
Published: December 2017

Qian, Jing and Peter Saggau. Modulation of transmitter release by action potential duration at the hippocampal CA3-CA1 synapse. J. Neurophysiol. 81: 288–298, 1999. Presynaptic Ca2+ influx through voltage-dependent Ca2+ channels triggers neurotransmitter release. Action potential duration plays a determinant role in the dynamics of presynaptic Ca2+ influx. In this study, the presynaptic Ca2+ influx was optically measured with a low-affinity Ca2+ indicator (Furaptra). The effect of action potential duration on Ca2+ influx and transmitter release was investigated. The K+ channel blocker 4-aminopyridine (4-AP) was applied to broaden the action potential and thereby increase presynaptic Ca2+ influx. This increase of Ca2+ influx appeared to be much less effective in enhancing transmitter release than raising the extracellular Ca2+ concentration. 4-AP did not change the Ca2+ dependence of transmitter release but instead shifted the synaptic transmission curve toward larger total Ca2+ influx. These results suggest that changing the duration of Ca2+ influx is not equivalent to changing its amplitude in locally building up an effective Ca2+ concentration near the Ca2+ sensor of the release machinery. Furthermore, in the presence of 4-AP, the N-type Ca2+ channel blocker ωCgTx GVIA was much less effective in blocking transmitter release. This phenomenon was not simply due to a saturation of the release machinery by the increased overall Ca2+ influx because a similar reduction of Ca2+ influx by application of the nonspecific Ca2+ channel blocker Cd2+ resulted in much more inhibition of transmitter release. Rather, the different potencies of ω-CgTx GVIA and Cd2+ in inhibiting transmitter release suggest that the Ca2+ sensor is possibly located at a distance from a cluster of Ca2+ channels such that it is sensitive to the location of Ca2+ channels within the cluster.
Synaptic Activation of GABAA Receptors Induces Neuronal Uptake of Ca2+ in Adult Rat Hippocampal Slices
Authors: Autere Anna-Maija , Lamsa Karri , Kaila Kai , Taira Tomi
Published: December 2017

Synaptic activation of GABAA receptors induces neuronal uptake of Ca2+ in adult rat hippocampal slices. Synaptically evoked transmembrane movements of Ca2+ in the adult CNS have almost exclusively been attributed to activation of glutamate receptor channels and the consequent triggering of voltage-gated calcium channels (VGCCs). Using microelectrodes for measuring free extracellular Ca2+([Ca2+]o) and extracellular space (ECS) volume, we show here for the first time that synaptic stimulation of γ-aminobutyric acid-A (GABAA) receptors can result in a decrease in [Ca2+]o in adult rat hippocampal slices. High-frequency stimulation (100–200 Hz, 0.4–0.5 s) applied in stratum radiatum close (≤0.5 mm) to the recording site induced a 0.1- to 0.3-mM transient fall in [Ca2+]o from a baseline level of 1.6 mM. Concomitantly, a 30–40% decrease in the ECS volume was seen. Exposure of drug-naı̈ve slices to the GABAA receptor antagonist picrotoxin (100 μM) first attenuated and only thereafter augmented the Ca2+ shifts. Application of ionotropic glutamate receptor antagonists resulted in a monotonic reduction of the Ca2+ response, but a large Ca2+ shift persisted (60–70% of the original), which was attenuated by a subsequent application of picrotoxin or bicuculline. In the absence of ionotropic glutamatergic transmission, pentobarbital sodium (100 μM), an up-modulator of the GABAA receptor, strongly enhanced the activity-evoked changes in [Ca2+]o. We suggest that the underlying mechanism of GABA-induced Ca2+ transients is the activation of VGCCs by bicarbonate-dependent GABA-mediated depolarizing postsynaptic potentials. Accordingly, stimulation-evoked Ca2+ shifts were inhibited by the membrane-permeant inhibitor of carbonic anhydrase, ethoxyzolamide (50 μM) or in N-2-hydroxyethylpiperazine- N′-2-ethanesulfonic acid (HEPES)–buffered HCO3-free solution. Neuronal Ca2+ uptake caused by intense synaptic activation of GABAA receptors may prove to be an important mechanism in the modulation of activity-dependent neuronal plasticity, epileptogenesis, and cell survival in the adult brain.
Evidence for an Eye-Centered Spherical Representation of the Visuomotor Map
Authors: Vetter Philipp , Goodbody Susan J. , Wolpert Daniel M.
Published: December 2017

Evidence for an eye-centered spherical representation of the visuomotor map. During visually guided movement, visual coordinates of target location must be transformed into coordinates appropriate for movement. To investigate the representation of this visuomotor coordinate transformation, we examined changes in pointing behavior induced by a local visuomotor remapping. The visual feedback of finger position was limited to one location within the workspace, at which a discrepancy was introduced between the actual and visually perceived finger position. This remapping induced a change in pointing that extended over the entire workspace and was best captured by a spherical coordinate system centered near the eyes.
Putrescine, Spermidine, and Spermine
Authors: Olle H
Published: December 2017

Putrescine was first isolated from putrifying meat and was thought of as a decomposition product;spermine was named from its occurrence in semen. These polyamines, however, are now known to have important roles in cell growth and differentiation. Their physiological significance can be studied by analyzing the consequences of depletion of the cellular polyamine content. The results include arrest of cell growth, differentiation, and division. Further results suggest that blocking of polyamine synthesis may have broad implications in clinical medicine.
Fever: A Hot Topic
Authors: Kluger MJ
Published: December 2017

Fever is the regulation of body temperature at an elevated "set point." Contact with a variety of pathogens, such as viruses or bacteria, will result in the release of a small protein, endogenous pyrogen or interleukin 1, from the host's white blood cells. This protein circulates to the brain where it is thought to raise the temperature set point via the production of a prostaglandin. Fevers occur throughout the vertebrates. The cold-blooded vertebrates (fishes, amphibians, reptiles) raise their body temperature by behaviorally selecting a warmer microhabitat. Warm-blooded vertebrates (birds and mammals) use both physiological and behavioral means to raise core temperature. Over the past decade data from both in vitro and in vivo studies support the hypothesis that moderate fevers are beneficial to the host;that is, fever as evolved as an adaptation to reduce the severity of infection.
Potassium Channels and Fluid Secretion
Authors: Peterson OH
Published: December 2017

Fluid secretion from exocrine glands can be switched on and off with great precision. Recent patch-clamp recordings of single-channel currents in acinar cells reveals that neurotransmitters and hormones control the opening of K+ channels. However, fluid secretion is due to transport of Na+ and Cl-, and movement of these ions occurs only when K+ can be transported simultaneously. Thus, by controlling K+ channels, neurotransmitters or hormones regulate Na+ and Cl-secretion.
Amniotic Fluid - Our First Environment
Authors: Wintour EM
Published: December 2017

The developing fetus is surrounded by amniotic fluid. In the first half of gestation this fluid closely resembles fetal extracellular fluid, but later it becomes hypotonic. Fetal urination and drinking as well as the permeability of fetal membranes (amnion and/or chorion) are important determinants of composition and volume. Hormones, such as prolactin and cortisol, may play a major role by affecting membrane permeability.
From Photon to Receptor Potential: the Biochemistry of Vision
Authors: Saibil HR
Published: December 2017

The perception of light incident on the retina begins with the photoisomerization of the vitamin A-derived chromophore of the visual pigment protein, rhodopsin. We now have a remarkably clear picture of the sequence of events in the photoreceptor cell, in which rhodopsin activates an enzyme cascade that alters the membrane potential. This generates the visual signal that is transmitted through the retinal nerve cells to the brain.
Eggs Affect the Activity of Spermatozoa
Authors: Dangott Lawrence J. , Garbers David L.
Published: December 2017

It has been known for several decades that animal spermatozoa respond to substances associated with or produced by eggs and/or the female reproductive tract. Sperm motility and metabolism are affected, and, in addition, chemotaxis has been reported in various invertebrates and lower vertebrates. The mechanisms of communication begin to be understood, receptors on the sperm cell have been identified, and early biochemical events following receptor activation have been defined.
Movement of Oxygen in Skeletal Muscle
Authors: Harris PD
Published: December 2017

In skeletal muscle the level of oxygen in outflowing venous blood is much higher than the level of oxygen in tissue. This puzzling finding suggests that oxygen moves in some unexpected way. The author uses the concept of short-circuit diffusion of oxygen between adjacent arterioles and venules to unravel the mystery and to provide new interpretations of microvascular responses to hypoxia and intermittent claudication.
How Do Sodium-Absorbing Cells Do Their Job and Survive?
Authors: Schultz SH , Randall L
Published: December 2017

To survive, all animal cells must maintain their normal intracellular ionic concentrations and volumes within narrow limits. This poses a particularly serious challenge to the cells of Na+-absorbing epithelia whose intracellular milieu is subject to assault by large and often rapidly changing rates of transcellular Na+ traffic. The ability of these cells to survive changes in the rate of Na+ entry through their apical membranes can be ascribed to parallel changes in the Na+-K+ exchange pumps and the K+ "leaks" at their basolateral membranes.
The Pineal Gland: An Important Link to the Environment
Authors: Reiter RJ
Published: December 2017

The pineal gland has two characteristic features: 1) virtually every aspect of its function is rhythmic and 2) its influence is extremely widespread. The production of its hormone, melatonin, is cyclic and is synchronized by the light-dark cycle of the environment. The reproductive consequences of the mammalian pineal are important but may be secondary to its broader functions as a synchronizer that entrains physiology to the appropriate season of the year. The significance of the pronounced 24-h cycle in human melatonin production has remained elusive.
An Important Region for Osmoregulation: The Anterior Wall of the Third Ventricle
Authors: McKinley MJ
Published: December 2017

The past decade has seen the recognition of a brain region that houses neural circuitry crucial for regulation of fluid and electrolyte balance in mammals. This important region lines the anterior wall of the third cerebral ventricle and contains neuronal elements involved in control of thirst and vasopressin secretion. Renal sodium excretion may also be controlled by this region, and it seems likely that angiotensin II influences neuronal function there.
Modulation of Ion Channels by Phosphorylation and Second Messengers
Authors: Reuter H
Published: December 2017

Ion channels are integral membrane proteins that regulate ion fluxes through the membrane;when channels are open, ions can move down their respective electrochemical gradients. The transitions between open-closed conformations, called gating, are regulated either by a change in membrane potential or by binding of ligands. Channel gating as well as channel availability can be modulated by biochemical reactions, such as phosporylation of the channel protein.
The Olfactory System as a Molecular Descriptor
Authors: Chanel J
Published: December 2017

The olfactory mucosa has a limited variety of membrane receptor sites, diversely distributed from one olfactory cell to another. The distribution pattern might provide an activation scheme that is spatially organized for each odorant. The distinct topological arrangement would then constitute a molecular descriptor of the odorant.
A New Approach to the Physiology of Lipid Transport
Authors: Redgrave TG
Published: December 2017

Lipids are transported in the plasma in large, complex aggregates. Their size and composition as well as their interaction with plasma proteins to form lipoproteins are important. The protein moiety plays a major role in mediating lipoprotein uptake and metabolism by tissues. Lipid emulsions of desired composition can be prepared, and their handling when injected into intact animals yields important insight into the metabolism of natural lipoproteins.
Renal Calcium Transport: Sites and Insights
Authors: Friedman PA
Published: December 2017

In the kidney the absorption of calcium in the proximal tubule is mediated largely through passive transport processes, in the distal tubule by hormone-sensitive transcellular movement, whereas the loop on Henle represents a hybrid situation. The ability of calcium-transporting cells to accommodate wide ranges of transcellular movement without disturbing cytosolic calcium-dependent processes suggests the presence of mechanisms to coordinate apical entry and basolateral efflux of calcium.
Fatty Acid-Binding Proteins and Their Physiological Significance
Authors: Glatz JFC , Van der Vusse GJ , Veerkamp JH
Published: December 2017

Fatty acid-binding proteins are found in extraordinary abundance in cells of mammalian tissues that are actively involved in the uptake or utilization of fatty acids, such as intestine, liver, and heart. They are small proteins, and different tissues contain distinct types. They are typically considered to be the intracellular counterpart of serum albumin and are thought to play an extensive role in cellular lipid homeostasis.
Coping With Asphyxia: Lessons From Seals
Authors: Elsner R , de Burgh Daly M
Published: December 2017

Seals and other aquatic mammals are endowed with adaptations to temporary cessation of breathing during their prolonged underwater submergence. The study of the reactions of these natural specialists to asphyxia and of the mechanisms that govern these reactions provides insight into the responses to asphyxia of other vertebrates.
Capillary Growth: Role of Mechanical Factors
Authors: Hudlicka O
Published: December 2017

Although various growth factors initiate angiogenesis under pathological circumstances, vessel growth in physiological conditions (e.g., development, training) is related to increased blood flow. This article stresses the role of blood flow in the stimulation of capillary growth in skeletal muscles and in the heart. Also discussed are various components (blood pressure, wall tension, shear stress, blood cells-endothelium interaction) possibly involved in angiogenesis.
Ion Transport by the Cornea
Authors: Wiederholt M
Published: December 2017

The cornea and lens of the eye are avascular transparent tissues that allow almost unimpeded transmission of light to the retina. The transparency of the cornea is a function of hydration, which in turn is affected by electrolyte transport processes across the cellular barriers.
Granulocyte: Friend and Foe
Authors: Schmid-Schonbein G, W.
Published: December 2017

Circulating granulocytes play an important role in microvascular perfusion and organ pathology. Compared with red cells, granulocytes are large, stiff cells that can adhere strongly to the vascular endothelium. This may cause accumulation of granulocytes in the microcirculation and obstruct capillaries and cause cardiovascular complications. The analysis of granulocyte kinetics in the circulation has helped us better understand the etiology of a wide class of cardiovascular disease.
Ionic Channels in Sea Urchin Sperm Physiology
Authors: Darszon A , Guerrero A , Lievano A , Gonzalez-Martinez M , Morales E
Published: December 2017

In sea urchin sperm, ionic fluxes modulate the activation of respiration and motility and the acrosome reaction, a prerequisite for egg fertilization. Ionic channels are present in the plasma membrane of these cells, and there is good evidence indicating that they are deeply involved in these processes.
Measurement of Regional Tissue Physiology Using Positron Emission Tomography
Authors: Jones T
Published: December 2017

The means for noninvasively studying aspects of regional tissue physiology using positron emission tomography are described. This is illustrated in a review of quantitative methods that have been developed and applied to the study of cerebral, cardiac, pulmonary, and neoplastic tissues.
Neuroendocrine Aspects of Learning and Memory Processes
Authors: de Wied D
Published: December 2017

Limbic structures are involved in learning and memory processes. These structures are richly innervated by fibers containing neurotransmitters and neuropeptides. Corticosteroids and adrenomedullary hormones and peptides related to acetylcholine, corticotrophin-releasing hormone, melanophore-stimulating hormone, oxytocin, vasopressin, and several others modulate learning and memory processes and limbic system activity.
Potential Role of Heparanase in Atherosclerosis
Authors: Campbell JH , Campbell GR
Published: December 2017

The mechanism by which a change in smooth muscle phenotype is effected in the artery wall during atherogenesis may be via release of extracellular matrix-degrading enzymes, particularly heparanase, from activated macrophages and T lymphocytes.
Role of Ion Exchange in Release of Biogenic Amines
Authors: Uvnas B , Aborg C-H
Published: December 2017

Mast cells, chromaffin cells, and nerves contain granule materials that have the characteristics of weak ion exchangers. Biogenic amines are stored in and released from these granules according to kinetics of ion exchange. Studies on isolated mast cells and on adrenals in vivo suggest that amines are released by ion exchange: cytoplasmic K+ being the releasing ion in the preexocytotic phase and Na+ in the exocytotic phase.
Role of Activity in Developing Synapses. Search for Molecular Mechanisms
Authors: Vrbova G , Lowrie M
Published: December 2017

The involvement of activity in synapse elimination at the neuromuscular junction is discussed, and a mechanism is proposed based on the molecular processes that are a consequence of normal neuromuscular activity.
The Control of Hemoglobin-Oxygen Binding in Vertebrate Animals
Authors: Wells RMG
Published: December 2017

The affinity of blood for O2 can now be explained in terms of the interaction of the hemoglobin molecule with cofactors. Recent advances in comparative physiology suggest that short-term compensatory changes in blood O2 affinity, which greatly alter the efficiency of the O2-delivery system in response to hypoxia, are typical for vertebrates. Control of O2 delivery by red blood cell organic phosphates is best interpreted in terms of plasticity of the system, rather than as an adaptive feature responsive to evolutionary selection pressure.
Glucoreceptor Systems: FFrom Control of Glycemia to Feeding Behavior
Authors: Timo-Iaria C
Published: December 2017

Hypoglycemia activates glucoreceptors in the lateral hypothalamic area, nuclei of the solitary tract, and liver and provokes reflexes that help maintain glycemia within the normal range. The metabolic activity thus induced seems to trigger hunger and subsequent feeding.
News From the Alveoli
Authors: Crone C , Saumon G , Basset G
Published: December 2017

Recent studies show that the alveolar epithelium performs solute-coupled fluid transport in the direction from the alveolar spaces to lung interstitial fluid. Na+-K+-ATPase plays a prime role for assuring the "dry" character of the alveoli.
Adenosine: A Retaliatory Metabolite or Not?
Authors: Newby AC , Worku Y , Meghji P , Nakazawa M , Skladanowski AC
Published: December 2017

Adenosine has been called a "retaliatory metabolite", since its physiological actions have a common tendency to redress an imbalance between energy demand and availability. Its formation is linked directly to the net breakdown of cytosolic ATP. This hypothesis is still useful to explain much of the physiology of adenosine but is challenged by evidence for adenosine formation from extracellular ATP.
Behavioral Influences on Coronary Blood Flow and Susceptibility to Arrhythmias
Authors: Verrier RL
Published: December 2017

Both stress and poststress states can induce myocardial ischemia and electrical instability by enhancing sympathetic discharge. Tonic activity of the vagus nerve exerts a protective action. The rapid-eye-movement phase of sleep can also cause coronary vasoconstriction. This observation may help to elucidate mechanisms responsible for nocturnal angina.
Ion Channels and Cell Volume Regulation: Chaos in an Organized System
Authors: Lewis SA , Donaldson P
Published: December 2017

Exposure of many vertebrate cells to solutions more dilute or concentrated than the physiological "norm" results in an initial increase or decrease in cell volume followed by a recovery of volume toward a normal value. Although the basic strategy for volume regulation is the same for cell types studied, the mechanism by which the cell regulates ion channels appears to be tissue dependent.
Atrial Tachycardias - A New Look
Authors: Rosenshtraukh LV , Zaitsev AV
Published: December 2017

Arrhythmogenic vagal effects commonly are related to shortening of atrial refractoriness, which increases a probability of circus movement of premature excitation. In clinical arrhythmias the mechanism of the premature excitation remains unclear. We suggest that vagally induced conduction block can provoke atrial premature beats and tachycardia.
High-Altitude Bird Flight: Exercise in a Hostile Environment
Authors: Fedde MR
Published: December 2017

A few species of birds, notably the bar-headed goose (Anser indicus), fly at great altitudes (9.000 m or 29.500 ft) and undergo severe hypoxia during their semiannual migration. Specializations in a number of organ systems of these birds appear to allow this activity.
The Act of Breathing
Authors: Macklem PT
Published: December 2017

During the last 30 years, quantification of chest wall motion, partitioning and analysis of pressures displacing chest wall, recognition that the diaphragm is composed of 2 muscles, and realization that rib cage is a 2-compartment system, each exposed to different pressure, has produced new insights into how mammals breathe.
Myogenic Regulation of Mammalian Skeletal Muscle Fibres
Authors: Hoh JFY
Published: December 2017

Motor nerves can only modify the phenotype of muscle fibres within a myogenically determined range. The particular range of a given fibre is an intrinsic property of that fibre, depending on the type of muscle (limb or jaw) and the specific tag imprinted upon it during development.
Peptidergic Innervation of the Mammalian Anterior Pituitary
Authors: Ju G , Liu S , Zhang X
Published: December 2017

The anterior pituitary is regulated by humoral and probably also by neural factors. Immunocytochemical studies have demonstrated substance P-, calcitonin gene-related peptide-, and galanin-like immunoreactive nerve fibers in the pars distalis of several mammalian species, and synapses have been identified on gland cells.
The Cardiac Connection
Authors: Jongsma HJ , Gros D
Published: December 2017

Development of lactic acidosis is essential in performance of heavy work. H+, locally produced with lactate during inadequate O2 flow to tissues, raises capillary PO2 and facilitates O2 diffusion to mitochondria. This provides feedback control when there is imbalance between O2 requirement and supply.
How Does Single Chemically Gated Ionic Channel Work?
Authors: Skok VI
Published: December 2017

Interaction of nicotinic acetylcholine receptor in nerve cell of mammalian sympathetic ganglion with a transmitter results in the appearance of a burst of the channel openings. Reduction of disulfide bonds in receptor protein removes the bursts, leaving only the channel single openings.
Inhibitory Vasomotor Neurons in the Caudal Ventrolateral Medulla Oblongata
Authors: Blessing WW
Published: December 2017

Tonically active, probably GABAergic, neurons in the caudal ventrolateral medulla oblongata decrease sympathetic vasomotor tone by directly inhibiting sympathoexcitatory premotor neurons in the rostral medulla. These caudal inhibitory vasomotor neurons may constitute the inhibitory link in the central baroreceptor-vasomotor pathway.
IGF-I, a Key Regulator of Renal Phosphate Transport and 1,25-Dihydroxyvitamin D3 Production During Growth
Authors: Caverzasio J , Bonjour J-P
Published: December 2017

During development of vertebrates the extracellular concentration of Pi and, consequently, the amount of Pi available for cellular growth and bone mineral deposition is maintained at a higher level than during adult life. Insulin-like growth factor I plays a specific role in this Pi economy.
Open Question: Has Thermogenesis in Muscle Been Overlooked and Misinterpreted?
Authors: Colquhoun EQ , Clark MG
Published: December 2017

Brown adipose tissue has been considered the major thermogenic tissue of the rat and, by implication, of other species. However, oxygen uptake by the perfused resting hindlimb is markedly accelerated by hormones, appears to be controlled by the vascular system, and may originate from vasoconstricting smooth muscle itself.
A Putative Role for Natriuretic Peptides in Fish Osmoregulation
Authors: Evans DH , Takei Y
Published: December 2017

Emerging evidence indicates that atrial natriuretic peptide-like peptide hormones may play a significant role in various aspects of fish osmoregulation. Surprisingly, the bulk of current evidence supports a role in salt rather than volume regulation.
Regulation of Prostacyclin Synthesis in Endothelial Cells
Authors: Carter TD , Pearson JD
Published: December 2017

Endothelial cells synthesize prostacyclin in response to a wide variety of vasoactive stimuli. The transduction pathway is dependent on elevation of intracellular Ca2+ and specifically desensitizes cells to the stimulus used, thus providing tight temporal regulation of the release of this potent vasodilator and inhibitor of platelet aggregation.
Interactions in the Insulin-Like Growth Factor Signaling System
Authors: Roberts CT, , LeRoith D
Published: December 2017

The insulin-like growth factors, IGF-I and IGF-II, are mitogenic peptides structurally related to insulin, which have widespread effects on growth and differentiation during development. These effects are mediated via activation of specific cell-surface receptors, and this activation is modulated by several species of IGF-binding proteins.
The Na-K Pump
Authors: Skou JC
Published: December 2017

The Na-K pump operates by a stepwise change in Na+ versus K+ affinities and a gating reaction governed by the reaction with ATP. The activity is regulated by the intra- as well as the extracellular Na+-to-K+ concentration ratios and is stimulated by insulin and catecholamines.
The Missing Error Signal—Regulation Beyond Negative Feedback
Authors: Somjen George G.
Published: December 2017

Homeostatic negative feedback fails to explain the essentially error-free regulation of bodily functions such as cardiorespiratory response, water intake, or temperature control. It seems likely that the performance is guided by past experience, which means that autonomic responses are learned at an early age.
Endothelin: Receptors and Transmembrane Signals
Authors: Thomas CP , Simonson MS , Dunn MJ
Published: December 2017

Since its discovery in 1988, much work has been done to expand our knowledge about the function and expression of the endothelin family of peptides. In this review we discuss the recently cloned endothelin receptors and give an overview of signal transduction events following endothelin receptor activation.
Pineal Gland in Synchronizing and Refining Physiological Events
Authors: Ebadi M , Samejima M , Pfeiffer RF
Published: December 2017

Some pineal functions, such as photoperiodic regulation of reproductive events, are elicited by melatonin itself;other events are caused by melatonin modulating and refining functions invested in neurotransmitters located in other structures and organs, which may differ from tissue to tissue, organ to organ, and species to species.
Clues to the Cell-Specific Synthesis of Complex Carbohydrates
Authors: Berger EG , Thurnher M
Published: December 2017

Important functions such as cell adhesion and cell recognition depend on complex carbohydrates (glycans) whose structures are remarkably diverse. Glycans are synthesized by specific glycosyltransferases. Their expression and topogenesis to the proper Golgi subcompartment, availability of sugar nucleotides, and undisturbed intracellular traffic are critical factors of cell-specific glycosylation.
Ca2+ Channels and Peptide Release From Neurosecretory Terminals
Authors: Wang X , Treistman SN , Wilson A , Nordmann JJ , Lemos JR
Published: December 2017

Evoked release of neuropeptides and/or neurotransmitters requires activation of membrane Ca2+ channels. Because of the generally small size and inaccessibility of nerve endings, most electrophysiological studies have observed this activation only in cell bodies. However, recent techniques have permitted insights into the diversity and behavior of Ca2+ channels in neurosecretory terminals.
Comparison of Functional Load in Rat and Guinea Pig Hearts
Authors: Kapelko VI , Novikova NA
Published: December 2017

Isolated rat hearts pump less cardiac output than guinea pig hearts at maximal volume load but develop higher left ventricular systolic pressure at increased resistance. These results allow us to understand the meaning of underlying peculiarities in the structure and function of cardiomyocytes of these two species.
Olympic Goal: Molecular and Cellular Approaches to Understanding Muscle Adaptation
Authors: Booth FW , Tseng BS
Published: December 2017

Skeletal muscle is a plastic tissue showing adaptations to training that permit more physical work with less fatigue. Delineation of basic mechanisms of these adaptations will allow the development of scientifically based programs of exercise as well as potential new drugs for the maintenance of physical fitness.
Quantal Secretion at Visualized Sympathetic Nerve Varicosities
Authors: Bennett MR
Published: December 2017

It has recently been shown that varicosities of single sympathetic nerve terminals possess a heterogeneous distribution of secretion probabilities. This discovery was made possible by the introduction of techniques that allow the visualization of a single live varicosity and the recording of the electrical signs of its secretion of quanta.
Atrial Natriuretic Factor in Central Cardiovascular Control
Authors: Oparil S , Wyss JM
Published: December 2017

A complete atrial natriuretic factor (ANF) synthetic, processing, and effector system is found in rat brain. ANF in critical brain regions, including anterior hypothalamic area and nucleus tractus solitarii, contributes importantly to the tonic control of blood pressure, sympathetic outflow, and baroreceptor reflex sensitivity in the spontaneously hypertensive rat.
Lessons Learned From Dopamine b-Hydroxylase Deficiency in Humans
Authors: Gary T , Robertson D
Published: December 2017

Dopamine b-hydroxylase deficiency is a genetic disorder in which affected patients cannot synthesize norepinephrine and epinephrine, in either the central or peripheral nervous system. Identification and treatment of this novel human physiological disorder will continue to lead to better understanding of the role of catecholamines in human physiology.
Signal Transduction by Intramitochondrial Ca2+ in Mammalian Energy Metabolism
Authors: McCormack JG , Denton RM
Published: December 2017

Hormones and other extracellular agents often stimulate energy-requiring processes such as muscle contraction and secretion through increases in cytosolic calcium. To preserve energy homeostasis, ATP formation must also be stimulated. One important mechanism involves increases in mitochondrial calcium and activation of key steps in the process of oxidative phosphorylation.
Hormones and Fibrosis: A Case for Lost Reciprocal Regulation
Authors: Weber KT
Published: December 2017

Fibrogenesis represents either a necessary or an unwanted process. Stimulators of fibrosis (e.g., angiotensin II, aldosterone, and endothelins) are normally counterbalanced by inhibitors (e. g., bradykinin, prostaglandins, and glucocorticoids). Fibrosis appears when this cooperative and balanced reciprocal regulation is lost.
Alkaline Stress-Induced Cell Transformation
Authors: Oberleithner Hans , Schwab Albrecht
Published: December 2017

Sustained alkalosis transforms epithelial cells in culture. Genotypically altered cells express an endogenous Ca2+ oscillator that probably is the motor for restless locomotion of these cells. Atomic force microscopy discloses membrane turnover processes during cell migration at the nanometer level.
Structural Correlates of K+ Channel Function
Authors: Taglialatela M , Brown AM
Published: December 2017

More complementary DNAs have been cloned for Voltage-dependent K+ channels than any other voltage-dependent ion channel. Purely functional studies anticipated this result because K+ currents are far more diverse than voltage-dependent Na+, Ca2+, or Cl currents, the other types of voltage-dependent ionic currents commonly dealt with.
Understanding Control of Exocytotic Secretion in Single Adenohypophysial Cells
Authors: Zorec R , Zupancic G , Rupnik M , Kocmur L , Grilc S , Kordas M
Published: December 2017

Stimulus-secretion coupling at the cellular level is studied by measuring changes in membrane capacitance in a variety of secretory cells. Attempts to gain new insight into the control of exocytosis in adenohypophysial cells by the patch-clamp technique are briefly outlined.
Nuclear Magnetic Resonance Detection of the Consequences of Transgene Expression
Authors: Koretsky AP
Published: December 2017

Physiological processes can be altered in a very specific manner using transgenic mouse techniques. Physiological processes can be noninvasively monitored using nuclear magnetic resonance imaging and spectroscopic techniques. Three illustrations of the combination of these two rapidly developing techniques to study neuronal function, energy metabolism, and sickle cell anemia are discussed.
Insights From Intraneural Recordings of Sympathetic Nerve Traffic in Humans
Authors: Wallin BG , Elam M
Published: December 2017

Microneurographic recordings reveal a marked differentiation between sympathetic traffic to different effectors (skin and muscle blood vessels, sweat glands) both with regard to firing pattern and responses to maneuvres. Consequently, data from one sympathetic nerve/ effector and physiological/pathological condition cannot be generalized.
Are All Cell Volume Changes the Same?
Authors: Strange k
Published: December 2017

Little is known about how cells sense volume and convert size signals into regulatory responses. Recent evidence suggests cells can detect more than just swelling or shrinkage. Cells may possess multiple volume detectors and volume regulatory effector pathways that respond specifically to the mechanism and magnitude of volume change.
Ca2+ Receptor-Dependent Regulation of Cellular Functions
Authors: Nemeth EF
Published: December 2017

It has been supposed that a cell-surface Ca2+ receptor enables parathyroid cells to detect and respond to extracellular Ca2+. The recent cloning of a G protein-coupled Ca2+ receptor solidifies this view. Ca2+ receptors regulate the activity of various cells and provide novel molecular targets for new pharmaceuticals.
Cell Volume: A Second Message in Regulation of Cellular Function
Authors: Lang F , Busch GL , Volkl H , Haussinger D
Published: December 2017

To survive, cells must avoid excessive alterations of cell volume. Thus cells have acquired a variety of strategies to main constancy of their volume, including the modification of ion flux across cell membranes and metabolic pathways. Hormones exploit these mechanisms for regulation of cellular function.
Glucose Transport and Glucose Homeostasis: New Insights From Transgenic Mice
Authors: Mueckler MM
Published: December 2017

Experiments with transgenic mice overexpressing glucose transporter isoforms demonstrate the preeminence of the transport step with respect to muscle glucose disposal and whole body glucose homeostasis. These studies suggest the feasibility of controlling diabetic hyperglycemia by pharmacological or genetic enhancement of muscle glucose transport.
Recent Advances in Cochlear Neurotransmission: Physiology and Pathophysiology
Authors: Pujol R , Eybalin M , Puel J-L
Published: December 2017

Recently, considerable progress has been made in the field of cochlear neurotransmitters. The glutamatergic nature of primary auditory synapses and related excitotoxic properties have strong pathophysiological consequences and clinical implications. Neurochemical advances also account for a much better understanding of the role of different components of the efferent olivocochlear system.
Controlling the Nongenomic Actions of 1,25 (OH)2D3
Authors: Farach-Carson MC , Devoll RE
Published: December 2017

1a, 25-Dihydroxyvitamin D3 [1,25(OH)2D3] is a potential therapeutic agent for treatment of many clinical disorders, but its tendency to produce hypercalcemia at therapeutic dosages is a barrier to its usefulness. Derivatives of 1,25(OH)2D3 have been synthesized that possess the beneficial genomic activities of 1,25(OH)2D3 but have reduced nongenomic effects, which may be correlated with a tendency to produce hypercalcemia.
Guanylin and Uroguanylin: Intestinal Peptide Hormones That Regulate Epithelial Transport
Authors: Forte LR , Hamra FK
Published: December 2017

Guanylin and uroguanylin are peptides that activate a membrane guanylate cyclase and control salt and water transport. Intestinal bacteria secrete toxins that mimic the actions of these peptides, causing a secretory form of diarrhea. Stimulation of guanylin/uroguanylin receptors in the kidney increases salt excretion. Thus guanylin and uroguanylin may regulate salt and water homeostasis.
Afferent and Efferent Synaptic Transmissions in Hair Cells
Authors: Ohmori H
Published: December 2017

Hair cells transduce mechanical information into electrical signal and, via afferent synapse, transmit it to the central nervous system (CNS). Hair cells receive cholinergic efferent innervation from the CNS, and a long-lasting membrane hyperpolarization is produced by activation of Ca2+-activated K+ channels. Acetylcholine may facilitate afferent synaptic transmission by suppressing K+ channels on the afferent nerve terminal.
Cardiac Chloride Currents
Authors: Harvey RD
Published: December 2017

Heart cells possess a number of different ion channels, most of which are cation selective. However, several Cl- conductance pathways have recently been identified. This article describes some of the different Cl- currents found in mammalian cardiac myocytes and discusses their likely contribution to the electrical activity of the heart.
One Hundred Years of Starling's Hypothesis
Authors: Michel C.
Published: December 2017

Since its formulation in 1896, Starling's hypothesis has been the most fundamental principle guiding investigations of microvascular permeability and fluid distribution between the blood and the tissues. The principle's explanatory powers have been strengthened greatly over the past 30 years by better understanding of the dynamic nature of the interstitial forces.
Angiotensin II and Baroreflex Control of Heart Rate
Authors: Reid IA
Published: December 2017

Angiotensin increases blood pressure without decreasing heart rate because it resets the baroreflex control of heart rate to a higher pressure. The resetting is mediated by central AT1 receptors and withdrawal of cardiac vagal tone. It is physiologically important because it minimizes baroreflex buffering and enhances the peptide's pressor activity.
From Potsdam to Berlin With Detours: The Life of Hermann von Helmholtz
Authors: Grüsser O.-J
Published: December 2017

Hermann von Helmholtz was one of the most versatile scientists of the 79th century. His contributions range from the first clear enunciation of the first law of thermodynamics (energy conservation) to the invention of the ophthalmoscope. The following is a brief summary of his life prepared after the centennial of his death.
Novel Kinase Signaling Cascades in Pancreatic Acinar Cells
Authors: Williams JA , Dabrowski A , Logsdon CD
Published: December 2017

Pancreatic secretagogues that activate digestive enzyme secretion through classic intracellular mediators such as Ca2+ also activate novel signaling kinase cascades. The best defined of these is the MAP kinase cascade, but cholecystokinin also activates jun kinase, p38 MAP kinase, and S6 kinase. These novel pathways are likely involved with pancreatic growth and gene expression.
Pleiotropic Role for GRKs and b-Arrestins in Receptor Regulation
Authors: Ferguson SSG , Zhang J , Barak LS , Caron MG
Published: December 2017

G protein-coupled receptor kinases and arrestin proteins are well-characterized mediators of agonist-dependent G protein-coupled receptor desensitization. These proteins are now shown to play a dual role in receptor regulation by mediating both receptor uncoupling and sequestration, a process important for receptor resensitization. b-Arrestins bound to phosporylated b2-adrenergic and angiotensin II type 1A receptors act as intracellular trafficking molecules specifically targeting these receptors for dynamin-dependent clathrin-coated vesicle-mediated sequestration.
Intestinal Iron Absorption: Cellular Mechanism and Regulation
Authors: Debnam ES , Srai SKS
Published: December 2017

Enterocyte iron transfer is crucial for body iron homeostasis, but the cellular processes involved are poorly understood. Recent work suggests the response to increased iron demand involves upregulation of transport at the brush border together with decreased translation of ferritin mRNA, thereby facilitation iron transfer to the blood.
How Does an Ion Channel Sense Voltage?
Authors: Papazian DM , Bezanilla F
Published: December 2017

Voltage-dependent ion channels underlie nerve and muscle excitability. Recent studies have increased our understanding of how voltage controls channel activity. Charged residues in transmembrane segments that contribute to the voltage sensor have been identified. During activation, voltage-sensing residues traverse a significant fraction of the transmembrane electric field, dramatically increasing the probability that the channel will enter an open, ion-conducting state.
New Concepts Concerning the Regulation of Renal Phosphate Excretion
Authors: Kumar R
Published: December 2017

Some tumors elaborate a phospaturic factor, "phosphatonin," that is unlike known peptide or sterol hormones. The same, or a similar, factor may exist in hypophosphatemic mice and humans with X-linked hypophosphatemic rickets. Such a factor may play a role in the control of phosphate homeostasis in normal physiological states.
Killing Mechanisms of Cytotoxic T Lymphocytes
Authors: Groscurth Peter , Filgueira Luis
Published: December 2017

Cytotoxic T lymphocytes mediate lysis of target cells by various mechanisms, including exocytosis of lytic proteins (perforin, granzymes) and receptor-ligand binding of Fas/APO molecules. Death of target cells is characterized by either necrosis or apoptosis, depending on the killing mechanism used and on the metabolism of the target cell itself.
Ion Permeability of the Nuclear Envelope
Authors: Mazzanti Michele
Published: December 2017

The nuclear envelope mediates nucleocytoplasmic communication. Nuclear pores transport proteins and RNA into and out of the nucleus. The pore is believed to allow free ion diffusion. Using an electrophysiological approach, we show the possible semipermeable properties of the envelope. To accomplish these functions we hypothesize a mechanism in which the pore complex acts as a molecular diaphragm.
Capacitative Calcium Entry
Authors: Holda Jaclyn R. , Klishin Andrey , Sedova Marina , Hüser Jörg , Blatter Lothar A.
Published: December 2017

Capacitative Ca2+ entry is a recently discovered Ca2+ entry pathway that is activated on depletion of intracellular Ca2+ stores, providing an avenue for store refilling. Despite recent progress in elucidating the capacitative Ca2+ entry pathway, the mysteries of its molecular identity, its biophysical properties, and the store depletion signal remain.
The Isolated Perfused Heart and Its Pioneers
Authors: Zimmer Heinz-Gerd
Published: December 2017

In 1866, Carl Ludwig together with Elias Cyon created the first isolated perfused frog heart preparation. Perfusion systems for the isolated mammalian heart were developed by H. Newell Martin in 1883 and by Oscar Langendorff in 1895. In its working mode, the isolated perfused rat heart was established in the 1960s.
Brain Cooling: An Economy Mode of Temperature Regulation in Artiodactyls
Authors: Jessen Claus
Published: December 2017

Artiodactyls employ selective brain cooling (SBC) regularly during experimental hyperthermia. In free-ranging antelopes, however, SBC often was present when body temperature was low but absent when brain temperature was near 42°C. The primary effect of SBC is to adjust the activity of the heat loss mechanisms to the magnitude of the heat stress rather than to the protection of the brain from thermal damage.
Regenerative Nerve Fiber Growth in the Adult Central Nervous System
Authors: Schwab Martin E.
Published: December 2017

Neurite growth and regeneration in the adult central nervous system (CNS) is extremely limited. An important factor contributing to these restrictions is specific growth inhibitory proteins associated with oligodendrocytes and CNS myelin. A major inhibitory factor is the antigen of a monoclonal antibody; the application of this neutralizing antibody to spinal cord- or brain-lesioned adult rats induces long-distance regeneration of lesioned axons, as well as a specific increase in sprouting and rewiring of the cortical output system to the brain stem and the spinal cord. These anatomic changes are paralleled by important functional recoveries of locomotion and precision movements.
Central Neuronal Histamine Contributes to Cardiovascular Regulation
Authors: Bealer Steven L.
Published: December 2017

Evidence suggests that central histaminergic neurons make important contributions to cardiovascular regulation. For example, histamine-containing neurons project to brain regions important for cardiovascular regulation. Furthermore, stimulation of central histamine receptors changes blood pressure and heart rate and alters activity of major vasoconstrictor systems. Finally, histamine metabolism is changed in hypertension.
Images of Action Potential Propagation in Heart
Authors: Salama Guy , Choi Bum-Rak
Published: December 2017

Activation and repolarization across mammalian hearts follow complex three-dimensional pathways that are governed by fiber structure, intercellular coupling, and action potentials (APs) with spatially heterogeneous properties. Voltage-sensitive dyes and imaging techniques offer new insights on how spatiotemporal heterogeneities of APs govern propagation, repolarization, and AV node conduction and help us visualize arrhythmias with previously unattainable details.
Cytosolic Calcium Oscillations in Smooth Muscle Cells
Authors: Savineau Jean-Pierre , Marthan Roger
Published: December 2017

In a variety of smooth muscle cells, agonists activating membrane receptors induce oscillations in the cytoplasmic Ca2+ concentration via an inositol trisphosphate-activated mechanism. Ca2+ oscillations participate in the control of cell membrane potential and the tone of smooth muscle. There is evidence that alterations in Ca2+ oscillations modulate smooth muscle responsiveness.