scholarly journals CONTRIBUTION OF THE Na+/H+ ANTIPORTER TO THE REGULATION OF INTRACELLULAR pH IN A CRAYFISH STRETCH RECEPTOR NEURONE

1993 ◽  
Vol 178 (1) ◽  
pp. 109-124
Author(s):  
N. Mair ◽  
H. Moser ◽  
F. Fresser
Keyword(s):  
Intracellular Ph ◽  
Ganglion Cells ◽  
Stretch Receptor ◽  
Muscle Fibres ◽  
Functional Aspects ◽  
Crayfish Stretch Receptor ◽  
Ionic Changes ◽  
The Individual ◽  
Improved Technique ◽  
Phi Regulation

Regulation of intracellular pH (pHi) following acidosis induced by NH4+/NH3 exposures was re-investigated in a crayfish stretch receptor neurone using H+- and Na+-selective microelectrodes. All experiments were performed in nominally HCO3-/CO2-free salines. From studies in Na+-free saline and from electrochemical calculations, we concluded that pHi regulation was dependent on extracellular Na+ concentration ([Na+]o). The half-maximal rate of pHi recovery had an apparent Michaelis-Menten constant of 21 mmol l-1 [Na+]o. The use of this experimental approach and an improved technique enabled us to observe pHi regulation even in Cl-- free saline, in contrast to earlier findings. In addition, amiloride (2 mmol l-1) inhibited the maximum rate of pHi recovery by about 80 %, SITS (1 mmol l- 1) by about 20 %. The results strongly suggest the operation of two separate pHi-regulating mechanisms, a Na+-dependent HCO3-/Cl- antiporter (probably the Na+/H+/HCO3-/Cl- antiporter described earlier) and a Na+/H+ antiporter. Both mechanisms have been described in crayfish ganglion cells and muscle fibres, but the individual contribution to pHi regulation varies considerably in these preparations. Functional aspects of the pHi-regulating mechanisms in relation to ionic changes during the moulting cycle are discussed.

Extracellular Ca2+ and its effect on acid extrusion in the crayfish stretch receptor neurone

1996 ◽  
Vol 199 (8) ◽  
pp. 1781-1789
Author(s):  
H Moser ◽  
N Mair ◽  
F Fresser
Keyword(s):  
Maximum Rate ◽  
Stretch Receptor ◽  
Membrane Properties ◽  
Astacus Astacus ◽  
Physiological Properties ◽  
Crayfish Stretch Receptor ◽  
Per Se ◽  
Ion Species ◽  
Acid Extrusion ◽  
Phi Regulation

1. In the stretch receptor neurones of the crayfish Astacus astacus, the intracellular pH (pHi), the intracellular Na+ concentration ([Na+]i) and the membrane potential (Em) were measured simultaneously using ion-selective and conventional microelectrodes. Normal Astacus saline (NAS), and salines containing varying amounts of Ca2+ (Ca2+-NAS) but of constant ionic strength, with Na+, Mg2+ or Ba2+ as substituting ions, were used to investigate the effects of extracellular Ca2+ concentration ([Ca2+]o) on pHi and pHi regulation, on [Na+]i and on Em. The maximum rate of pHi recovery was used as a measure of pHi regulation. Acid loads were imposed using the NH4+/NH3 rebound technique. 2. [Ca2+]o affected pHi, pHi regulation, [Na+]i and Em. The magnitudes of the effects were inversely related to [Ca2+]o and were specific to the ion used for [Ca2+]o substitution. 3. Compared with controls, increasing [Ca2+]o threefold (in exchange for Na+) elicited some alkalization, a 7 % faster maximum rate of pHi recovery and generally lower values of [Na+]i. 4. In low-Ca2+ or Ca2+-free NAS (substitutions by Na+ or Mg2+), pHi became more acid, the maximum rate of pHi recovery was reduced by up to 50 % and [Na+]i was generally higher. The effects were faster and larger at lower [Ca2+]o, and stronger with Na+ than with Mg2+ as the substituting ion. 5. In Ca2+-free NAS (Ca2+ substituted for by Ba2+), the effects on pHi, on the maximum rate of pHi recovery and on [Na+]i were generally small. In this respect, Ba2+ had similar physiological properties to Ca2+ and was almost equally effective. 6. Changes in Em, including rapid depolarizations and occasional burst activity in Ca2+-free NAS, indicate that alterations in the properties of the membrane, such as a change in its permeability or selectivity, are occurring. Measurements of [Na+]i support this view. In addition, Ba2+ per se induced a (small) depolarization, as shown when Ba2+ was present in NAS or in low-Ca2+ NAS. 7. Changes in [Ca2+]o affected [Na+]i. *[Na+]i is defined as [Na+]i determined at the onset of the maximum rate of pHi recovery, and the ratio *[Na+]i/[Na+]o at that instant was calculated. A linear relationship between the maximum rate of pHi recovery and the *[Na+]i/[Na+]o ratio was found, irrespective of the amount and of the ion species used for [Ca2+]o substitution. This is strong evidence that pHi and pHi regulation were indirectly affected by [Ca2+]o, which altered membrane properties and thus caused a change in [Na+]i. We could find no evidence for a direct contribution of [Ca2+]o to acid extrusion or to a direct modulatory action on the transport protein of the Na+/H+ antiporter.

scholarly journals Effect of gamma-aminobutyric acid on intracellular pH in the crayfish stretch-receptor neurone

1991 ◽  
Vol 156 (1) ◽  
pp. 349-360 ◽  
Author(s):  
J. Voipio ◽  
M. Pasternack ◽  
B. Rydqvist ◽  
K. Kaila
Keyword(s):  
Intracellular Ph ◽  
Action Potentials ◽  
Initial Rate ◽  
Reversal Potential ◽  
Stretch Receptor ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Anion Channels ◽  
Co2 Partial Pressure ◽  
Crayfish Stretch Receptor

The effect of gamma-aminobutyric acid (GABA) on intracellular pH (pHi) was examined in the crayfish stretch-receptor neurone using H(+)-selective microelectrodes and a two-microelectrode voltage clamp. In the presence of 30 mmol l-1 HCO3- (pH 7.4), application of GABA (0.5 mmol l-1) produced a mean fall in pHi of 0.26 units. The initial rate of fall of pHi was attributable to a net influx of acid equivalents of 6.3 mmol l-1 min-1. In the nominal absence of HCO3-, GABA had little effect on pHi. The HCO3(−)-dependent acidosis caused by GABA was inhibited by picrotoxin (0.1 mmol l-1) but not by depletion of extracellular and intracellular Cl-. Acetazolamide (0.1 mmol l-1) decreased the rate of fall of pHi caused by a step increase in CO2 partial pressure as well as by GABA, which indicates that the neurone contains carbonic anhydrase. In the presence of both Cl- and HCO3-, the reversal potential of the GABA-activated current was more positive than under nominally HCO3(−)-free conditions. In line with this, GABA induced a marked HCO3(−)-dependent depolarization, and this depolarizing action was enhanced in the absence of Cl- so as to lead to triggering of action potentials. All these observations support the conclusion that the GABA-induced fall in pHi is due to a net efflux of HCO3- through the inhibitory anion channels.

Objective Measurement of Sustained Pupillary Constriction: A Pilot Study Using an App-Based Pupilometer

2020 ◽  
pp. 57-63
Keyword(s):  
Ganglion Cells ◽  
Modern Technology ◽  
Objective Measurement ◽  
Retinal Ganglion ◽  
Case Examples ◽  
Pupillary Reaction ◽  
Sympathetic Nervous Systems ◽  
Pupillary Constriction ◽  
The Individual ◽  
The Right

Background: The pupillary reaction is controlled by the two main branches of the autonomic nervous system, namely the parasympathetic and sympathetic nervous systems. New discoveries in pupil research has identified that intrinsically photosensitive retinal ganglion cells have an impact on pupillary constriction, particularly sustained pupillary constriction. In the current paper, an objective measurement of sustained pupillary constriction versus the inability to maintain sustained pupillary constriction are observed. The variability in the sustained pupillary constriction, i.e. Alpha Omega pupil, can be objectively identified with the use of modern technology. Case Examples: Two female subjects were adapted to dim illumination, and then two objective pupil measurements of the right eye using Reflex – PLR Analyzer by BrightLamp© (Indianapolis, IN, USA) with sustained illumination were obtained. Subject 1, a 25 year-old-female, demonstrated normal ability of the pupil to constrict and sustain constriction for 10 seconds. She was used as a control for subject 2. Subject 2, a 27 year-old-female, demonstrated the inability to sustain pupillary constriction. She reported being under great psychological stress. Her pupil began to re-dilate between 2 and 3 seconds after the initial constriction. Conclusion: Objective pupillometry can be used to assist in many diagnoses and provides the clinician invaluable information on the state of the individual, and qualifications of sustained pupillary constriction can now be assessed in an objective manner.

A Histochemical Study of Dehydrogenase Activity in the Pectoralis Major Muscle of the Pigeon and certain other Vertebrate Skeletal Muscles

1958 ◽  
Vol s3-99 (48) ◽  
pp. 469-473
Author(s):  
J. C. GEORGE ◽  
K. S. SCARIA
Keyword(s):  
Dehydrogenase Activity ◽  
Skeletal Muscles ◽  
Pectoralis Major Muscle ◽  
Breast Muscle ◽  
Muscle Fibres ◽  
Triphenyl Tetrazolium Chloride ◽  
Tetrazolium Chloride ◽  
Unique System ◽  
Oxidative Processes ◽  
The Individual

Certain dehydrogenases in the breast muscle of the pigeon and fowl and the leg muscle of the fowl and frog were studied histochemically by the use of 2:3:5: triphenyl tetrazolium chloride. The dehydrogenase activity was found to have a relationship with the colour and the mitochondrial content of the individual muscle fibres. In the pigeon breast muscle, however, the broad white fibres did not show the presence of any of the enzymes studied. It is therefore concluded that these fibres in the pigeon breast muscle are a unique system in which none of the oxidative processes concerned takes place; they cannot be considered as analogous to the white fibres of the other muscles studied.

scholarly journals National Identity: Formation and Realisation Through Poetry

wisdom ◽  
2021 ◽  
Vol 17 (1) ◽  
pp. 146-161
Author(s):  
Tetiana URYS ◽  
Tetiana KOZAK ◽  
Svitlana BARABASH
Keyword(s):  
National Identity ◽  
Identity Formation ◽  
National Culture ◽  
Literary Work ◽  
Effective Factor ◽  
Functional Aspects ◽  
Creative Personality ◽  
Important Means ◽  
The Individual ◽  
National Identity Formation

National culture, especially literature, contains invaluable nation-building potential and is an effective factor in influencing the development of the national identity of the individual and the ethnic group as a whole. In the process of forming literary works, the author’s consciousness and subconscious play an im­portant role, so they are not only one of the best ways of expressing a creative personality and a form of its reaction to events occurring in the outside world, but also one of the most important means of forming the national identity of the recipients. Therefore, such a literary work contains a modus of national identity. The main content of this concept in the literature is revealed in the article. Its theoretical components and their functional aspects in the text are defined and analysed. The modus of national identity is formulated as a way of realising the identity of one with his nation through certain aesthetic elements and structures at all levels of literary work as an artistic system. Such element-dominants are motives, artistic imagery, lyrical character as the main expression of the author’s thoughts, as well as archetypes, symbols and place names.

Intracellular pH recovery from lactic acidosis of single skeletal muscle fibres

1988 ◽  
Vol 66 (12) ◽  
pp. 1560-1564 ◽  
Author(s):  
Y. E. Allard
Keyword(s):  
Skeletal Muscle ◽  
Lactic Acid ◽  
Intracellular Ph ◽  
Buffer Capacity ◽  
Ringer Solution ◽  
Sartorius Muscle ◽  
Muscle Fibres ◽  
Diffusion Limited ◽  
Skeletal Muscle Fibres ◽  
Frog Sartorius

Intracellular pH (pHi, measured with H+-selective microelectrodes, in quiescent frog sartorius muscle fibres was 7.29 ± 0.09 (n = 13). Frog muscle fibres were superfused with a modified Ringer solution containing 30 mM HEPES buffer, at extracellular pH (pHo) 7.35. Intracellular pH decreased to 6.45 ± 0.14 (n = 13) following replacement of 30 mM NaCl with sodium lactate (30 mM MES, pHo 6.20). Intracellular pH recovery, upon removal of external lactic acid, depended on the buffer concentration of the modified Ringer solution. The measured values of the pHi recovery rates was 0.06 ± 0.01 ΔpHi/min (n = 5) in 3 mM HEPES and was 0.18 ± 0.06 ΔpHi/min (n = 13) in 30 mM HEPES, pHo 7.35. The Na+–H+ exchange inhibitor amiloride (2 mM) slightly reduced pHi recovery rate. The results indicate that the net proton efflux from lactic acidotic frog skeletal muscle is mainly by lactic acid efflux and is limited by the transmembrane pH gradient which, in turn, depends on the extracellular buffer capacity in the diffusion limited space around the muscle fibres.

Memoirs: The Neuro-Muscular Mechanism of the Gill of Pecten

1930 ◽  
Vol s2-73 (291) ◽  
pp. 365-392
Author(s):  
S. B. SETNA
Keyword(s):  
Feeding Habits ◽  
Adductor Muscle ◽  
The Body ◽  
Muscle Fibres ◽  
Direct Stimulation ◽  
Gill Filaments ◽  
Lateral Extent ◽  
Branchial Nerve ◽  
The Individual ◽  
Stimulation Of

Experimental. 1. The contraction of the adductor-muscle which follows stimulation of the palial nerve is preceded by a marked contraction of the ctenidial axis, so that the gill contracts before the adductor-muscle becomes active. This movement of the ctenidium is abolished if the main branchial nerve is cut near its origin. 2. The gills of Pecten possess a neuromuscular mechanism which is to some extent independent of the rest of the body, so that excised gills when stimulated react in the same way as an attached gill. 3. The lamellae of the gill possess two distinct types of movement. (a) When the surface of the gill is stimulated by contact with a glass rod or by carmine particles, the frontal surfaces of the two lamellae approach each other; the movement very often being executed by the lamella which is not actually being stimulated. The lateral extent of these movements (concertina movements) is roughly proportional to the intensity of the stimulus. Such movements normally appear to transfer the bulk of the material on to the mantle. Separation of the main branchial nerve abolishes these movements. (b) Each principal filament is capable of moving the ordinary filaments to which it is attached. This movement (flapping movement) is due to the movements of the interfilamentar junctions which alternatively move up and down at right angles to their length. This motion is independent of the branchial nerve and can be produced by direct stimulation of very tiny pieces of the individual filaments. 4. The significance of gill movements to feeding habits is discussed. The course of food particles depends on the nature of the stimuli affecting the gill. Histological. 5. The ctenidial axis and the principal filaments have a stratum of anastomosing nerve-cells which appear to form a true nerve-net comparable to that of the mantle. 6. The gill receives nerve-fibres from two sources, the brain and the visceral ganglion. The subsidiary branchial nerve is a structure hitherto unknown in the molluscan gill; so far its function is unknown. Each gill has four main longitudinal nerve-trunks. 7. The osphradium of the gill has a much more extensive distribution than has hitherto been supposed. 8. Two sets of muscles exist at the base of the gill-filaments, and these are responsible for movements of the lamellae. The muscle-fibres are non-striated. 9. The principal filaments are connected to the ordinary filaments by processes containing true muscle-cells, and by these cells movements of the filaments are effected.

Memoirs: The Muscles of the Adult Honey-bee (Apis mellifera L.)

1928 ◽  
Vol s2-71 (284) ◽  
pp. 563-651
Author(s):  
GUY D. MORISON
Keyword(s):  
Apis Mellifera ◽  
Alimentary Canal ◽  
Muscular Activity ◽  
Reproductive Organs ◽  
Muscle Fibres ◽  
Muscle Attachment ◽  
Apparent Lack ◽  
Histological Appearance ◽  
The Individual ◽  
Alary Muscles

1. The entire musculature of the alimentary canal is described in gross and in histological detail. The development of the muscle is considered. The innervation is described, likewise the tracheation and its relation to muscular activity and the bloodstream. 2. The heart is described with a detailed histological account of its muscle-fibres. Its tracheation is described and its apparent lack of innervation is discussed. 3. The ‘alary’ muscles of the dorsal diaphragm are described with a detailed account of their histology, innervation, and tracheation. 4. The ventral diaphragm is described as well as the histology, innervation, and tracheation of its muscle-fibres. The course of blood and physiological questions connected with it receive discussion. 5. The muscles of the reproductive organs of drone, queen, and worker are described with particular reference to the histology, innervation, tracheation, and physiology of their fibres. 6. The indirect muscles of the wings (fibrous muscle) have their histology, innervation, and tracheation described in detail. The method of contraction of the entire muscles and of the individual fibres and fibrils is discussed. The sarcosomes are described with their physiological significance to contraction. 7. The attachment of all the types of muscle found in the bee is described in histological detail. Different opinions of muscle attachment to chitin are summarized. 8. Throughout the paper, histological measurements are given for the various types of muscle-fibres and their nuclei in the three castes of bee. Since in the three castes the histological appearance is so similar for each type of muscle, the illustrations have been limited to portions of the muscles of worker bees.

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