bluuebunny/crossref_metadata_2025 huggingface dataset:
Motor Patterns for Human Gait: Backward Versus Forward Locomotion
Authors: Grasso R. , Bianchi L. , Lacquaniti F.
Published: December 2017

Grasso, R., L. Bianchi, and F. Lacquaniti. Motor patterns for human gait: backward versus forward locomotion. J. Neurophysiol. 80: 1868–1885, 1998. Seven healthy subjects walked forward (FW) and backward (BW) at different freely chosen speeds, while their motion, ground reaction forces, and electromyographic (EMG) activity from lower limb muscles were recorded. We considered the time course of the elevation angles of the thigh, shank, and foot segments in the sagittal plane, the anatomic angles of the hip, knee, and ankle joints, the vertical and longitudinal ground reaction forces, and the rectified EMGs. The elevation angles were the most reproducible variables across trials in each walking direction. After normalizing the time course of each variable over the gait cycle duration, the waveforms of all elevation angles in BW gait were essentially time reversed relative to the corresponding waveforms in FW gait. Moreover, the changes of the thigh, shank, and foot elevation covaried along a plane during the whole gait cycle in both FW and BW directions. Cross-correlation analysis revealed that the phase coupling among these elevation angles is maintained with a simple reversal of the delay on the reversal of walking direction. The extent of FW–BW correspondence also was good for the hip angle, but it was smaller for the knee and ankle angles and for the ground reaction forces. The EMG patterns were drastically different in the two movement directions as was the organization of the muscular synergies measured by cross-correlation analysis. Moreover, at any given speed, the mean EMG activity over the gait cycle was generally higher in BW than in FW gait, suggesting a greater level of energy expenditure in the former task. We argue that conservation of kinematic templates across gait reversal at the expense of a complete reorganization of muscle synergies does not arise from biomechanical constraints but may reflect a behavioral goal achieved by the central networks involved in the control of locomotion.
Gustatory Responses of the Hamster Mesocricetus auratus to Various Compounds Considered Sweet by Humans
Authors: Danilova Vicktoria , Hellekant Göran , Tinti Jean-Marie , Nofre Claude
Published: December 2017

Danilova, Vicktoria, Göran Hellekant, Jean-Marie Tinti, and Claude Nofre. Gustatory responses of the hamster Mesocricetus auratus to various compounds considered sweet by humans. J. Neurophysiol. 80: 2102–2112, 1998. The taste of 30 compounds was studied in the golden hamster with three different methods: single-fiber recordings, two-bottle preference (TBP), and conditioned taste aversion (CTA) tests. On the whole, the results showed that the sense of taste in the hamster differs in many respects from that in humans because, of 26 tested compounds known as sweet to humans, 11 had no taste or tasted differently. The results also supported the notion that activity in S-fibers elicits liking and activity in Q- or H-fibers rejection. Specifically hierarchial cluster analysis of 36 single fibers from the chorda tympani proper nerve separated N-, H-, and S-clusters consisting of 11 sucrose-, 14 NaCl-, and 11 citric-best fibers. Ace-K, cyanosuosan, N-4-cyanophenyl- N′-cyanoguanidineacetate (CCGA), d-tryptophan, N-3,5-dichlorophenyl- N′-( S)-α-methylbenzylguanidineacetate (DMGA), saccharin, SC-45647, and suosan stimulated only the S-fibers, were significantly preferred in TBP tests, and generalized to sucrose in the CTA tests. Ethylene glycol stimulated the N-fibers in addition to the S-fibers. This explains its generalization to sucrose in CTA. Its toxicity may contribute to its rejection in TBP tests. Sodium cyclamate stimulated a few N- but no S-fibers, which may explain the nondiscriminatory TBP and CTA results. Glycine elicited its largest response in the S-fibers, although it also stimulated other fibers. The resulting mixed taste sensation may explain why it was not preferred in TBP, although it generalized to sucrose in the CTA. Alitame, aspartame, N-4-cyanophenylcarbamoyl-l-aspartyl-( R)-α-methylbenzylamine (CAM), N-4-cyanophenylcarbamoyl-( R, S)-3-amino-3-(3,4-methylenedioxyphenyl) propionic acid (CAMPA), N-( S)-2-methylhexanoyl-l-glutamyl-5-amino-2-pyridinecarbonitrile (MAGAP), N-1-naphthoyl-l-glutamyl-5-amino-2-pyridinecarbonitrile (NAGAP), NHDHC, superaspartame, and thaumatin were among the compounds considered sweet by humans that gave no response, were not discriminated in the TBP test, and gave no generalization in the CTA tests.
Changes in Brain Activity During Motor Learning Measured With PET: Effects of Hand of Performance and Practice
Authors: van Mier H. , Tempel L. W. , Perlmutter J. S. , Raichle M. E. , Petersen S. E.
Published: December 2017

van Mier, H., L. W. Tempel, J. S. Perlmutter, M. E. Raichle, and S. E. Petersen. Changes in brain activity during motor learning measured with PET: effects of hand of performance and practice. J. Neurophysiol. 80: 2177–2199, 1998. The aim of this study is to assess brain activity measured during continuous performance of design tracing tasks. Three issues were addressed: identification of brain areas involved in performing maze and square tracing tasks, investigation of differences and similarities in these areas related to dominant and nondominant hand performance, and most importantly, examination of the effects of practice in these areas. A total of 32 normal, right-handed subjects were instructed to move a pen with the dominant right hand (16 subjects) or nondominant left hand (16 subjects) continuously through cut-out maze and square patterns with their eyes closed during a 40-s positron emission tomography (PET) scan to measure regional blood flow. There were six conditions: 1) holding the pen on a writing tablet without moving it (rest condition); 2) tracing a maze without practice; 3) tracing the same maze after 10 min of practice; 4) tracing a novel maze; and tracing an easily learned square design at 5) high or 6) low speed. To identify brain areas generally related to continuous tracing, data analyses were performed on the combined data acquired during the five tracing scans minus rest conditions. Areas activated included: primary and secondary motor areas, somatosensory, parietal, and inferior frontal cortex, thalamus, and several cerebellar regions. Then comparisons were made between right- and left-hand performance. There were no significant differences in performance. As for brain activations, only primary motor cortex and anterior cerebellum showed activations that switched with hand of performance. All other areas, with the exception of the midbrain, showed activations that were common for both right- and left-hand performance. These areas were further analyzed for significant conditional effects. We found patterns of activation related to velocity in the contralateral primary motor cortex, related to unskilled performance in right premotor and parietal areas and left cerebellum, related to skilled performance in supplementary motor area (SMA), and related to the level of capacity at which subjects were performing in left premotor cortex, ipsilateral anterior cerebellum, right posterior cerebellum and right dentate nucleus. These findings demonstrate two important principles: 1) practice produces a shift in activity from one set of areas to a different area and 2) practice-related activations appeared in the same hemisphere regardless of the hand used, suggesting that some of the areas related to maze learning must code information at an abstract level that is distinct from the motor performance of the task itself.
Dopamine Modulates Two Potassium Currents and Inhibits the Intrinsic Firing Properties of an Identified Motor Neuron in a Central Pattern Generator Network
Authors: Kloppenburg Peter , Levini Robert M. , Harris-Warrick Ronald M.
Published: December 2017

Kloppenburg, Peter, Robert M. Levini, and Ronald M. Harris-Warrick. Dopamine modulates two potassium currents and inhibits the intrinsic firing properties of an identified motor neuron in a central pattern generator network. J. Neurophysiol. 81: 29–38, 1999. The two pyloric dilator (PD) neurons are components [along with the anterior burster (AB) neuron] of the pacemaker group of the pyloric network in the stomatogastric ganglion of the spiny lobster Panulirus interruptus. Dopamine (DA) modifies the motor pattern generated by the pyloric network, in part by exciting or inhibiting different neurons. DA inhibits the PD neuron by hyperpolarizing it and reducing its rate of firing action potentials, which leads to a phase delay of PD relative to the electrically coupled AB and a reduction in the pyloric cycle frequency. In synaptically isolated PD neurons, DA slows the rate of recovery to spike after hyperpolarization. The latency from a hyperpolarizing prestep to the first action potential is increased, and the action potential frequency as well as the total number of action potentials are decreased. When a brief (1 s) puff of DA is applied to a synaptically isolated, voltage-clamped PD neuron, a small voltage-dependent outward current is evoked, accompanied by an increase in membrane conductance. These responses are occluded by the combined presence of the potassium channel blockers 4-aminopyridine and tetraethylammonium. In voltage-clamped PD neurons, DA enhances the maximal conductance of a voltage-sensitive transient potassium current ( I A) and shifts its V act to more negative potentials without affecting its V inact. This enlarges the “window current” between the voltage activation and inactivation curves, increasing the tonically active I A near the resting potential and causing the cell to hyperpolarize. Thus DA's effect is to enhance both the transient and resting K+ currents by modulating the same channels. In addition, DA enhances the amplitude of a calcium-dependent potassium current ( I O(Ca)), but has no effect on a sustained potassium current ( I K( V)). These results suggest that DA hyperpolarizes and phase delays the activity of the PD neurons at least in part by modulating their intrinsic postinhibitory recovery properties. This modulation appears to be mediated in part by an increase of I A and I O(Ca). I A appears to be a common target of DA action in the pyloric network, but it can be enhanced or decreased in different ways by DA in different neurons.
Phase Reversal of Biomechanical Functions and Muscle Activity in Backward Pedaling
Authors: Ting Lena H. , Kautz Steven A. , Brown David A. , Zajac Felix E.
Published: December 2017

Phase reversal of biomechanical functions and muscle activity in backward pedaling. Computer simulations of pedaling have shown that a wide range of pedaling tasks can be performed if each limb has the capability of executing six biomechanical functions, which are arranged into three pairs of alternating antagonistic functions. An Ext/Flex pair accelerates the limb into extension or flexion, a Plant/Dorsi pair accelerates the foot into plantarflexion or dorsiflexion, and an Ant/Post pair accelerates the foot anteriorly or posteriorly relative to the pelvis. Because each biomechanical function (i.e., Ext, Flex, Plant, Dorsi, Ant, or Post) contributes to crank propulsion during a specific region in the cycle, phasing of a muscle is hypothesized to be a consequence of its ability to contribute to one or more of the biomechanical functions. Analysis of electromyogram (EMG) patterns has shown that this biomechanical framework assists in the interpretation of muscle activity in healthy and hemiparetic subjects during forward pedaling. Simulations show that backward pedaling can be produced with a phase shift of 180° in the Ant/Post pair. No phase shifts in the Ext/Flex and Plant/Dorsi pairs are then necessary. To further test whether this simple yet biomechanically viable strategy may be used by the nervous system, EMGs from 7 muscles in 16 subjects were measured during backward as well as forward pedaling. As predicted, phasing in vastus medialis (VM), tibialis anterior (TA), medial gastrocnemius (MG), and soleus (SL) were unaffected by pedaling direction, with VM and SL contributing to Ext, MG to Plant, and TA to Dorsi. In contrast, phasing in biceps femoris (BF) and semimembranosus (SM) were affected by pedaling direction, as predicted, compatible with their contribution to the directionally sensitive Post function. Phasing of rectus femoris (RF) was also affected by pedaling direction; however, its ability to contribute to the directionally sensitive Ant function may only be expressed in forward pedaling. RF also contributed significantly to the directionally insensitive Ext function in both forward and backward pedaling. Other muscles also appear to have contributed to more than one function, which was especially evident in backward pedaling (i.e., BF, SM, MG, and TA to Flex). We conclude that the phasing of only the Ant and Post biomechanical functions are directionally sensitive. Further, we suggest that task-dependent modulation of the expression of the functions in the motor output provides this biomechanics-based neural control scheme with the capability to execute a variety of lower limb tasks, including walking.
Correlated Firing in Rabbit Retinal Ganglion Cells
Authors: DeVries Steven H.
Published: December 2017

Correlated firing in rabbit retinal ganglion cells. A ganglion cell’s receptive field is defined as that region on the retinal surface in which a light stimulus will produce a response. While neighboring ganglion cells may respond to the same stimulus in a region where their receptive fields overlap, it generally has been assumed that each cell makes an independent decision about whether to fire. Recent recordings from cat and salamander retina using multiple electrodes have challenged this view of independent firing by showing that neighboring ganglion cells have an increased tendency to fire together within ±5 ms. However, there is still uncertainty about which types of ganglion cells fire together, the mechanisms that produce coordinated spikes, and the overall function of coordinated firing. To address these issues, the responses of up to 80 rabbit retinal ganglion cells were recorded simultaneously using a multielectrode array. Of the 11 classes of rabbit ganglion cells previously identified, coordinated firing was observed in five. Plots of the spike train cross-correlation function suggested that coordinated firing occurred through two mechanisms. In the first mechanism, a spike in an interneuron diverged to produce simultaneous spikes in two ganglion cells. This mechanism predominated in four of the five classes including the onbrisk transient cells. In the second mechanism, ganglion cells appeared to activate each other reciprocally. This was the predominant pattern of correlated firing in off brisk transient cells. By comparing the receptive field profiles of on andoff brisk transient cells, a peripheral extension of theoff brisk transient cell receptive field was identified that might be produced by lateral spike spread. Thus an individualoff brisk transient cell can respond both to a light stimulus directed at the center of its receptive field and to stimuli that activate neighboring off brisk transient cells through their receptive field centers.
Three-Independent-Compartment Chamber to Study In Vitro Commissural Synapses
Authors: Khazipov Roustem , Desfreres Luc , Khalilov Ilgam , Ben-Ari Yehezkel
Published: December 2017

Khazipov, Roustem, Luc Desfreres, Ilgam Khalilov, and Yehezkel Ben-Ari. Three-independent-compartment chamber to study in vitro commissural synapses. J. Neurophysiol. 81: 921–924, 1999. We describe a novel chamber in which the two intact neonatal rat hippocampi and the commissural fibers are placed in three independent compartments separated by latex membranes and perfused selectively with different solutions. A set of control tests showed that the compartments are well isolated: 1) methylene blue or eosin applied to one compartment did not diffuse to other compartments when verified via the microscope, and spectrophotometry revealed that <1/10.000th of the dye diffuses to other compartments; 2) tetrodotoxin (1 μM) applied to the commissural compartment blocked the synaptic responses evoked contralaterally without affecting those evoked on the ipsilateral side. This chamber enables a wide range of experiments that cannot be performed in conventional chambers, e.g., to study the maturation and plasticity of the commissural connections, bilateral synchronization of the rhythmic activities in the limbic system, commissural propagation of the epileptiform activities, etc.
Differential expression of putative transbilayer amphipath transporters
Authors: HALLECK MARGARET S. , LAWLER JOSEPH F. , BLACKSHAW SETH , GAO LING , NAGARAJAN PRIYA , HACKER COLEEN , PYLE SCOTT , NEWMAN JASON T. , NAKANISHI YOSHINOBU , ANDO HIROSHI , WEINSTOCK DANIEL , WILLIAMSON PATRICK , SCHLEGEL ROBERT A.
Published: December 2017

Halleck, Margaret S., Joseph F. Lawler, Jr., Seth Blackshaw, Ling Gao, Priya Nagarajan, Coleen Hacker, Scott Pyle, Jason T. Newman, Yoshinobu Nakanishi, Hiroshi Ando, Daniel Weinstock, Patrick Williamson, and Robert A. Schlegel. Differential expression of putative transbilayer amphipath transporters. Physiol. Genomics 1: 139–150, 1999.—The aminophospholipid translocase transports phosphatidylserine and phosphatidylethanolamine from one side of a bilayer to another. Cloning of the gene encoding the enzyme identified a new subfamily of P-type ATPases, proposed to be amphipath transporters. As reported here, mammals express as many as 17 different genes from this subfamily. Phylogenetic analysis reveals the genes to be grouped into several distinct classes and subclasses. To gain information on the functions represented by these groups, Northern analysis and in situ hybridization were used to examine the pattern of expression of a panel of subfamily members in the mouse. The genes are differentially expressed in the respiratory, digestive, and urogenital systems, endocrine organs, the eye, teeth, and thymus. With one exception, all of the genes are highly expressed in the central nervous system (CNS); however, the pattern of expression within the CNS differs substantially from gene to gene. These results suggest that the genes are expressed in a tissue-specific manner, are not simply redundant, and may represent isoforms that transport a variety of different amphipaths.
A genome scan for QTL influencing milk production and health traits in dairy cattle
Authors: HEYEN D. W. , WELLER J. I. , RON M. , BAND M. , BEEVER J. E. , FELDMESSER E. , DA Y. , WIGGANS G. R. , VanRADEN P. M. , LEWIN H. A.
Published: December 2017

Heyen, D. W., J. I. Weller, M. Ron, M. Band, J. E. Beever, E. Feldmesser, Y. Da, G. R. Wiggans, P. M. VanRaden, and H. A. Lewin. A genome scan for QTL influencing milk production and health traits in dairy cattle. Physiol. Genomics 1: 165–175, 1999.—A genome scan was conducted in the North American Holstein-Friesian population for quantitative trait loci (QTL) affecting production and health traits using the granddaughter design. Resource families consisted of 1,068 sons of eight elite sires. Genome coverage was estimated to be 2,551 cM (85%) for 174 genotyped markers. Each marker was tested for effects on milk yield, fat yield, protein yield, fat percentage, protein percentage, somatic cell score, and productive herd life using analysis of variance. Joint analysis of all families identified marker effects on 11 chromosomes that exceeded the genomewide, suggestive, or nominal significance threshold for QTL effects. Large marker effects on fat percentage were found on chromosomes 3 and 14, and multimarker regression analysis was used to refine the position of these QTL. Half-sibling families from Israeli Holstein dairy herds were used in a daughter design to confirm the presence of the QTL for fat percentage on chromosome 14. The QTL identified in this study may be useful for marker-assisted selection and for selection of a refined set of candidate genes affecting these traits.
Regulation of Body Fluid Volume: The Atrial Natriuretic Factor
Authors: Genest J , Marc C
Published: December 2017

The discovery of the atrial natriuretic factor is a major breakthrough for our understanding of the regulation of body fluid volume. It plays a major role in vasorelaxation and in hypertensive and edematous states. The progress made in the last two years is a testimony to the powers of the new analytical techniques for isolation and characterization of peptides.
Hormonal and Neural Mechanisms of Sodium Appetite
Authors: Fregly MJ , Rowland NE
Published: December 2017

A strong appetite for salt seems to be a normal link in the complex mechanisms that serve to maintain a normal sodium content of the organism. Experiments with rats have helped to unravel many aspects of the endocrine mechanisms that are involved in regulating sodium balance and salt appetite, but more work is needed to understand the mechanisms that induce salt appetite in different species.
Endothelium-Derived Relaxing Factor: In Search of the Endogenous Nitroglycerin
Authors: Fridovich I , Hagen P-O , Murray JJ
Published: December 2017

A mediator released from vascular endothelium is characterized by a potent relaxing activity on vascular smooth muscle as well as an inhibitory activity on platelet aggregation. It is distinctly different from prostacyclin and is referred to as endothelial-derived relaxing factor or EDRF. It is extremely labile, but the recent chemical stabilization of the elusive factor should help unravel its identity and define the activity of this important physiological regulator.
Diving Responses: Fact or Fiction
Authors: Blix AS
Published: December 2017

The classical concept of the diving response emphasizes the observed selective vasoconstriction and bradycardia. It has recently been questioned, however, whether these responses can be considered normal reflex adjustments to diving because animals, when they dive voluntarily, usually show much less bradycardia, and presumably less vasoconstriction, than when they are forcibly submerged. These apparent differences in the expression of the responses to submergence may be less important than appear at first glance.
Calcium-Dependent Proteases: A Prevalent Proteolytic System of Uncertain Function
Authors: DeMartino GN , Croall DE
Published: December 2017

Calcium-dependent proteases are found in a wide variety of tissues from many animal species. They are intracellular enzymes that for activation require calcium in the micromolar range. In addition to the calcium dependence, two regulatory proteins have been identified, one an inhibitor and one an activator. These interactions indicate a highly complex role for calcium-dependent proteolysis in the intracellular processing of proteins.
Milk Secretion: Autocrine Control
Authors: Peaker M , Wilde CJ
Published: December 2017

Milk secretion is modulated by local chemical feedback inhibition, a mechanism that matches supply of milk to the demand. An inhibitor of milk secretion that is present in milk plays a major role in this inhibition. It is a constituent of the whey proteins, and its moleculars mass is in the range of 10,000-30,000 Da.
Sensing Position and Movements of the Fingers
Authors: McCloskey DI , Macefield G , Gandevia SC , Burke D
Published: December 2017

Normal subjects are able to sense movements imposed on the fingers or to sense altered positions of the fingers. These senses may be mediated by sensory receptors in muscles that operate on a joint, in the capsules and ligmaents of the joints, and in the related skin. Although much has been learned about proprioception from experiments on the fingers, some properties of digital proprioception are quite unusual.
Capillarity and Oxidative Capacity of Muscles
Authors: Hoppeler, H , Kayar, SR
Published: December 2017

Muscle capillaries serve as the final pathway for oxygen and substrate exchange between blood and muscle cells. Intuitively one suspects that the size of the capillary bed should be matched to the metabolic needs of the cells it supplies, implying some optimization between structure and functional demands, and that oxygen should be a dominating factor. Is this concept of an optimal design merely an intellectually appealing idea or can it be supported by evidence?
Macrophagelike Properties of Endothelial Cells
Authors: Ryan US
Published: December 2017

Despite their separate embryological origins, endothelial cells and macrophages have many functional similarities. Both can bind and ingest particulates, including live bacteria, with consequent responses, including a respiratory brust, augmented phagocytic activity, accelerated migration, and cell division. However, endothelial cells are less effective at killing ingested organisms, which may lead to complications.
Magnetic Resonance Imaging Multispectral Tissue Classification
Authors: Vannier MW , Speidel CM , Rickman DL
Published: December 2017

The application of NASA multispectral image processing technology for analysis of magnetic resonance imaging scans has been studied. Software and hardware capability has been developed, and a statistical evaluation of multispectral analysis application to magnetic resonance imaging scans of the head has been performed.
Platelet 5-Hydroxytryptamine and Vascular Adrenergic Nerves
Authors: Cohen RA
Published: December 2017

Platelets contain and release large amounts of 5-hydroxytryptamine that can influence the function of vascular adrenergic nerves. The immediate effect on neuronal function of low concentrations of the amine is to inhibit norepinephrine release. 5-Hydroxytryptamine may also be accumulated by the same uptake mechanism that reaccumulates norepinephrine into the adrenergic nerve endings. In diseased blood vessels where platelet aggregation occurs, 5-hydroxytryptamine may therby assume an alternative transmitter role, altering the function of the sympathetic nerves.
Renal Lymph: Vital for the Kidney and Valuable for the Physiologist
Authors: Pinter GG
Published: December 2017

Drainage of extravasated proteins from the interstitium is a vital function of renal lymph. In addition, it has a valuable role as a source of information about the renal interstitium. Information uniquely provided by lymph allows characterization of macromolecular permeabilities of postglomerular exchange vessels in the renal cortex under physiological conditions and in disease, e.g., in experimental diabetes mellitus. Various defense mechanisms are discussed that are instrumental in keeping the balance between reabsorption of fluid from the tubules and uptake of reabsorbed fluid by the peritubular capillaries. The role of lymph in these mechanisms is highlighted.
Oxidant Mechanisms in Glomerular Injury
Authors: Shah SV
Published: December 2017

An increasing body of evidence derived from both in vitro and in vivo studies utilizing leukocyte-dependent and leukocyte-independent models of glomerulonephritis suggests an important role for reactive oxygen metabolites in glomerular pathophysiology.
Dietary Essential Polyunsaturated Fatty Acids and Blood Pressure
Authors: Tresguerres JAF , Lahera V , Cachofeiro MV
Published: December 2017

A high intake of polyunsaturated fatty acids has been reported as being able to reduce blood pressure and to protect against several cardiovascular diseases. These effects have been observed in hypertensive and normotensive humans and in experimental models of hypertension. Prostaglandins have been considered responsible for these beneficial effects, although other vasoactive factors could also be involved.
Mechanisms of Head Stabilization
Authors: Dutia MB
Published: December 2017

Vestibular, visual, and proprioceptive inputs interact to stabilize the head on the neck. Reflexes involved in head stabilization are useful experimental models of motor systems controlling large skeletal muscles.
Beat-To-Beat Variations of Heart Rate Reflect Modulation of Cardiac Autonomic Outflow
Authors: Saul JP
Published: December 2017

What is most intriguing about heart rate (HR) variability is that there is so much of it. HR is constantly responding both rapidly and slowly to various physiological perturbations. We now understand that the frequency and amplitude of these HR fluctuations are indicative of the autonomic control systems underlying the response.
The Preemptive Cringe
Authors: Roddie Ian C.
Published: December 2017

What stance should academics take when faced with uncongenial pressures applied by an unsympathetic government?
Peripheral Neuroendocrine Interrelationships in the Cervical Region
Authors: Cardinali DP , Romeo HE
Published: December 2017

The effect of peripheral sympathetic nerves on adenohypophysial, thyroxine (T4), calcitonin, and parathyroid hormone release and effects of parasympathetic innervation on T4 release are discussed. Nerves arriving at the endocrine organs are parallel pathways through which the brain communicates with the endocrine system.
The Importance of Vascular Capacitance in Cardiovascular Control
Authors: Hainsworth R
Published: December 2017

Vascular capacitance refers to degree of active constriction of vessels (mainly veins) which affects return of blood to the heart and thus cardiac output. Capacitance changes participate in cardiovascular reflexes but passive volume changes resulting from changes in transmural pressure are likely to be at least as important.
The Role of Vascular Alpha-2-Adrenoceptors as Cutaneous Thermosensors
Authors: Flavahan NA
Published: December 2017

Alpha-2-Adrenoceptors are found predominantly in cutaneous arteries and veins. These receptors are responsible for the unique thermosensitivity of the cutaneous circulation, enabling it to constrict during local cooling, thereby preventing heat loss. This mechanism appears to be increased in Raynaud's disease, causing an exaggerated response to cold.
Endothelial Modulation of Arteriolar Tone
Authors: Kuo L , Davis MJ , Chilian WM
Published: December 2017

The microvascular endothelium modulates many vasoactive reactions of arterioles, which help maintain proper perfusion. Endothelium-dependent mechanisms also help coordinate the overall vascular response of the microvasculature during physiological stresses.
Nitric Oxide and Vasoactive Intestinal Peptide: Cotransmitters of Smooth Muscle Relaxation
Authors: Said SI
Published: December 2017

The L-arginine-nitric oxide pathway and vasoactive intestinal peptide, both widely distributed in tissues and organs, have different localizations, different activation and release mechanisms, and different signal-transduction systems. Their combined action, however, enhances the effectiveness of their vascular and nonvascular smooth muscle relaxation.
Phosphotyrosine Protein Phosphatases: Master Key Enzymes in Signal Transduction
Authors: Van Hoof C , Goris J , Merlevede W
Published: December 2017

Tyrosine phosphorylation plays a crucial role in the regulation of cellular events. Phosphotyrosine phosphatases are pivotal enzymes in quenching signals and could thus be considered as high-specificity safety devices, screening intra- and extracellular signal transduction to engineer a coordinated control of cell function, proliferation, and differentiation.
Biological Basis of the Stress Response
Authors: Henry JP
Published: December 2017

Recent work shows that differing perceptions of stress result in different patterns of neuroendocrine activation. An easily handled challenge elicits norepinephrine and testosterone rises with success. With increasing anxiety, active coping shifts to a more passive mode. Epinephrine, prolactin, renin, and fatty acids increase. As the distress grows, cortisol augments.
Nonadrenergic Noncholinergic Inhibitory Transmitters of the Gut
Authors: Makhlouf GM , Grider JR
Published: December 2017

Vasoactive intestinal peptide acts as a delivery and transduction system to regenerate nitric oxide in target muscle cells, thereby ensuring the survival and effectiveness of a potent but otherwise short-lived messenger and making optimal use of both limbs of the cyclic nucleotide signaling system that mediates relaxation.
Immunoregulatory Failure in the Pathophysiology of Hypertension
Authors: Khraibi AA
Published: December 2017

Positive correlation has been found between serum immunoglobulin G levels and blood pressure in untreated hypertensive patients. In the Okamoto spontaneously hypertensive rat, several functional indexes of the immune system are depressed. Selective interventions with the immune system result in antihypertensive effects or delay development of spontaneous hypertension.
Establishment of Optimal Juxtaglomerular Cell Models
Authors: Rayson BM , Cannizzo SJ
Published: December 2017

Circulating renin is synthesized, stored, and released from juxtaglomerular (JG) cells, first identified in 1925. A range of JG cell systems has been developed to promote the characterization of the regulation of renin synthesis and release, with some recent success. Each approach, though, remains subject to specific drawbacks.
Oncogene-Transformed Renal Cell Lines: Physiological and Oncogenetic Studies
Authors: Ronco PM , Prie D , Piedagnel R , Lelongt B
Published: December 2017

Use of inducible oncogenes has recently boosted interest in immortalized cell lines derived by transfection of primary cultures or from transgenic mice. When the oncogene is functional, cells exhibit a transformed phenotype, whereas upon oncogene inactivation, they can differentiate up to the level of the parental cells.
Mechanical Properties of Basement Membrane
Authors: Welling LW , Zupka MT , Welling DJ
Published: December 2017

Basement membranes from renal tubules, capillaries, venules, and pulmonary alveolar wall all have remarkably similar elastic properties and Young's moduli. Strength and safety margin, however, are far smaller in the alveolar wall, perhaps as a result of its complexity of design.
Role of Endothelin in Central Cardiorespiratory Control: Modern and Classical Approaches
Authors: Kuwaki T , Kurihara Y , Kurihara H , Yazaki Y , Kumada M
Published: December 2017

Mutant mice deficient in endothelin-1 (ET-1) were created by using gene-targeting techniques. ET-1 +/- heterozygous mice showed elevated arterial pressure accompanied by diminished arterial PO2 and impaired respiratory reflexes. Endogenous ET-1 thus plays a physiological role in cardiorespiratory control. Neural structures in the ventral medulla oblongata appear to participate in this process.
The Size Principle: Still Working After All These Years
Authors: Cope TC , Pinter MJ
Published: December 2017

Orderly recruitment of motor units is viewed by many as a fundamental motor control strategy. The size principle is an idea that attempts to explain how orderly recruitment operates. Does the size principle work? We summarize how the size principle came about, consider its mechanisms, and probe its limits.
Long- and Short-Term Regulation of the Na+-K+-Pump in Skeletal Muscle
Authors: Clausen T
Published: December 2017

In skeletal muscle, activity and capacity of the Na+ -K+ pump are controlled by several hormones, contractile activity, growth, and nutrition. Acute or chronic reduction of the pump capacity inhibits contractile performance. Conversely, acute hormonal stimulation of the Na+ -K+ pump leads to marked, rapid force recovery in muscles where contractility is suppressed by high extracellular K+.
Ion Channels and Human Genetic Diseases
Authors: Rojas CV
Published: December 2017

Ion channels have lately received much attention by geneticists and molecular biologists owing to the discovery of several inherited human "ion channels disorders". Important contributions to the understanding not only of pathogenesis, but also of the structure-function relationship of ion channels, have come from the functional analysis of these natually occurring mutant channels.
Intrarenal Alterations in Experimental Liver Cirrhosis
Authors: Atucha M , Joaquin G-E
Published: December 2017

In liver cirrhosis, renal reabsorption of water and sodium precedes ascites formation. Reduced renal excretory rates can be found in the absence of changes in plasma levels of main systemic hormones. It is possible that intrarenal elevations of antinatriuretic systems participate in retention of water and sodium in early cirrhosis.
Signal Transduction and Cell Volume Regulation in Plant Leaflet Movements
Authors: Moran N , Yueh YG , Crain RC
Published: December 2017

Leaflet movements and underlying cell volume changes are visual indicators of ion transport in specialized cells of various plants. These cells are an attractive model to study regulation of plant ion transport. We focus on the effect of light, the biological clock, and mechanosensing on ion channels mediating cell volume regulation.
Fever: How May Circulating Pyrogens Signal the Brain?
Authors: Blatteis CM , Sehic E
Published: December 2017

Recent data suggest that fever may be initiated by products of liver macrophages that activate subdiaphragmatic vagal afferents. In the brain, these inputs may be transmitted to fever-producing sites via noradrenergic pathways;prostaglandin E2 may be the ultimate pyrogenic mediator.
Prostanoids: Intrinsic Modulators of Cerebral Circulation
Authors: Leffler CW
Published: December 2017

Prostanoids are important autocrine/paracrine modulators of the cerebral circulation. They can directly affect vascular smooth muscle by activating second messenger pathways leading to changes in vascular tone. They also can have more indirect effects: modifying responses of vascular smooth muscle to other stimuli and providing critical intercellular communication for coordinated vascular responses to important physiological stimuli.
Physiology and Biophysics of the 100-m Sprint
Authors: Summers RL
Published: December 2017

The 100-m sprint is the most exciting of Olympic events, and the winner is often called the "world's fastest human." The physiology of this race is unique and invovles our most primordial survival mechanisms. A computer stimulation predicts the theoretical "physiological" limits for human achievement in this event.
HIF-1, a Mediator of the Molecular Response to Hypoxia
Authors: Gassmann M , Wenger RH
Published: December 2017

Normal oxygen delivery is essential for vertebrate homeostasis. Adaptation to changes in oxygen supply involves complex but specific changes in gene expression. This review summarizes recent information on the molecular anatomy and physiology of the first hypoxia-inducible transcription factor (HIF-1) discovered in mammals. Identifications of HIF-1 provides an important tool for investigating oxygen-sensing and signaling mechanisms.
Chasing Myocardial Calcium: A 35-Year Perspective
Authors: Langer G. A.
Published: December 2017

Before 1960, it was generally thought reasonable to define cardiac muscle function by extrapolation from results found for skeletal muscle. As heart muscle was studied in its own right, it became obvious, particularly with respect to its calcium metabolism, that the heart has developed unique mechanisms for contractile control.
Spatial Memory and Learning in Transgenic Mice: Fact or Artifact?
Authors: Wolfer David P. , Stagljar-Bozicevic Marijana , Errington Mick L. , Lipp Hans-Peter
Published: December 2017

Spatial learning of transgenic mice is often assessed in the Morris watermaze, where mice must use distant cues to locate a submerged platform. Such learning is confounded by species-specific noncognitive swimming strategies. Factor analysis permits cognitive and noncognitive strategies to be disentangled and their association with electrophysiological phenomena to be investigated.
The Dichotomy of MIP Family Suggests Two Separate Origins of Water Channels
Authors: Ishibashi Kenichi , Sasaki Sei
Published: December 2017

MIP family proteins can be divided into two groups according to their primary sequences. The CHIP group is predominant in the plant and animal kingdoms and functions primarily as water channels. The GLP group is a minor group with limited prevalence and functions primarily as glycerol transporters. Both prototypes are present in bacteria and may have evolved separately.
Meditation as a Voluntary Hypometabolic State of Biological Estivation
Authors: Young John Ding-E , Taylor Eugene
Published: December 2017

Meditation, a wakeful hypometabolic state of parasympathetic dominance, is compared with other hypometabolic conditions, such as sleep, hypnosis, and the torpor of hibernation. We conclude that there are many analogies between the physiology of long-term meditators and hibernators across the phylogenetic scale. These analogies further reinforce the idea that plasticity of consciousness remains a key factor in successful biological adaptation.
Do Cellular Heat Acclimation Responses Modulate Central Thermoregulatory Activity?
Authors: Horowitz Michal
Published: December 2017

The classical concept of heat acclimation is of an autonomically controlled array of integrative physiological processes, improving heat tolerance. New evidence suggests that a temporal interplay between opposing autonomic and peripheral cell-originated responses, switched on by heat and autonomic stimulation of the cell membrane, and a marked increase in the stock of the inducible 70-kDa heat shock protein contribute to widening of the thermoregulatory activity span.
“Enteric Tears”: Chloride Secretion and Its Neural Regulation
Authors: Cooke Helen J.
Published: December 2017

Neural reflex circuits within the submucosal plexus and axon reflexes via extrinsic primary afferents control chloride secretion by intestinal epithelial cells. The regulation of chloride secretion is a complex interplay between excitatory and inhibitory influences from neurotransmitters and chemical messengers released from epithelial, endocrine, and immune cells.
Understanding the Physiology of the Blood-Brain Barrier: In Vitro Models
Authors: Grant Gerald A. , Abbott N. Joan , Janigro Damir
Published: December 2017

Endothelial cells exposed to inductive central nervous system factors differentiate into a blood-brain barrier phenotype. The blood-brain barrier frequently obstructs the passage of chemotherapeutics into the brain. Tissue culture systems have been developed to reproduce key properties of the intact blood-brain barrier and to allow for testing of mechanisms of transendothelial drug permeation.
Cytokines and Feeding
Authors: Plata-Salamán Carlos R.
Published: December 2017

Cytokines inhibit feeding through peripheral and brain mechanisms. Behavioral, cellular, and molecular studies show that interactions among cytokines, neurotransmitters, and peptides and modulation of hypothalamic neurons are involved in cytokine-induced feeding inhibition. This action of cytokines is relevant to the control of feeding in health and disease.
Bile Acids: The Good, the Bad, and the Ugly
Authors: Hofmann Alan F.
Published: December 2017

Bile acids, amphipathic end products of cholesterol metabolism, are “good” in the infant because they enhance lipid absorption and thereby promote growth. Bile acids also induce bile flow and biliary lipid secretion. The enterohepatic circulation of bile acids is “bad” in the adult because it downregulates hepatocyte low-density lipoprotein receptor activity and thereby elevates plasma cholesterol levels. Defects in bile acid metabolism such as impaired biosynthesis or transport are “ugly” because they cause morbidity and death. New approaches for treating these defects are being developed.
SCFAs: The Enigma of Weak Electrolyte Transport in the Colon
Authors: Sellin Joseph H.
Published: December 2017

Short-chain fatty acids are the predominant luminal anions in the colon (>75 mM) and thus create a rather unique environment for transporting epithelium. The colon absorbs short-chain fatty acids, either by diffusion of the protonated species across the apical membrane or by an anion exchange process with bicarbonate. Additionally, short-chain fatty acids modulate Na absorption, Cl secretion, intracellular pH, and cell volume.
Probing Nanometer Structures with Atomic Force Microscopy
Authors: Shao Zhifeng
Published: December 2017

Atomic force microscopy (AFM) can generate high-resolution images of the surface of biological specimens and can also probe the interactions between and within single macromolecules. Thus isolated heterogeneous biological structures can be studied in submolecular detail with AFM.
Sensorimotor Integration at the Dorsal Column Nuclei
Authors: Mariño Jorge , Martinez Luis , Canedo Antonio
Published: December 2017

Interaction among primary afferents, corticofugal fibers, and intrinsic elements allows for sensorimotor integration at the dorsal column nuclei. The interneurons permit the spatial localization, the recurrent collaterals synchronize the activity of projecting cells with overlapping receptive fields, and the corticofugal fibers induce a central zone of activity surrounded by a peripheral zone of inhibition.
The Reward Signal of Midbrain Dopamine Neurons
Authors: Schultz Wolfram
Published: December 2017

Dopamine projections from the midbrain to striatum and frontal cortex play a major role in behavioral reactions controlled by rewards. Recent experiments have shown that dopamine neurons code the discrepancy between the prediction and occurrence of rewards and in this way signal a crucial learning term for approach behavior.
Mechanisms of Modulation of a Neural Network
Authors: El Manira Abdeljabbar , Wallén Peter
Published: December 2017

Neural networks form the basis for the generation and control of various patterns of behavior. Such networks are subjected to modulatory systems that influence their operation and, thereby, the behavior. In the lamprey locomotor network, analysis on the ion channel, synaptic, and cellular levels has given new insights into the organization of such modulatory systems.
Myoglobin: Just an Oxygen Store or Also an Oxygen Transporter?
Authors: Jürgens Klaus D. , Papadopoulos Simon , Peters Thomas , Gros Gerolf
Published: December 2017

Besides acting as an oxygen store during times of reduced blood oxygen supply, myoglobin can also facilitate intracellular oxygen transport by diffusion of oxymyoglobin along a Po2 gradient. We reassess the importance of myoglobin-facilitated oxygen diffusion by applying new findings on the intracellular diffusivity of myoglobin in a model calculation.
Born Again Bone: Tissue Engineering for Bone Repair
Authors: Braddock Martin , Houston Parul , Campbell Callum , Ashcroft Patrick
Published: December 2017

Destruction of bone tissue due to disease and inefficient bone healing after traumatic injury may be addressed by tissue engineering techniques. Growth factor, cytokine protein, and gene therapies will be developed, which, in conjunction with suitable carriers, will regenerate missing bone or help in cases of defective healing.
Toward a Physiological Understanding of Human Dexterity
Authors: Wiesendanger Mario , Serrien Deborah J.
Published: December 2017

Dexterity, defined as the skillful manipulation of the hands, is now amenable to physiological investigation. Two topics are discussed here: grasping (i.e., hand-object coupling) and bimanual coordination. Dexterity depends on powerful, distributed neural networks and is particularly vulnerable to brain lesions. A knowledge of physiological mechanisms is needed to deal with these neurological problems.
Vestibular Signals in Self-Orientation and Eye Movement Control
Authors: Hess Bernhard J. M.
Published: December 2017

The central vestibular system receives afferent information about head position as well as rotation and translation. This information is used to prevent blurring of the retinal image but also to control self-orientation and motion in space. Vestibular signal processing in the brain stem appears to be linked to an internal model of head motion in space.
When Active Muscles Lengthen: Properties and Consequences of Eccentric Contractions
Authors: Lindstedt S. L. , LaStayo P. C. , Reich T. E.
Published: December 2017

When the force applied to a muscle exceeds the force produced by the muscle it will lengthen, absorbing mechanical energy. These eccentric contractions, which result in both braking and storing elastic recoil energy in normal locomotion, require very little metabolic energy, yet they are characterized by high force production.