The paired neuroglial and interglial membranes in the crayfish stretch receptor and their local disorganization

2014 ◽  
Vol 93 (5) ◽  
pp. 707-713 ◽  
Author(s):  
Grigory Fedorenko ◽  
Marya Neginskaya ◽  
Alexej Fedorenko ◽  
Anatoly Uzdensky
Keyword(s):  
Stretch Receptor ◽  
Crayfish Stretch Receptor

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.

Mechanoreceptors and touch

2019 ◽  
pp. 76-98
Author(s):  
Gordon L. Fain
Keyword(s):  
Caenorhabditis Elegans ◽  
Molecular Biology ◽  
Stretch Receptor ◽  
Sensory Transduction ◽  
Merkel Cells ◽  
Anatomy And Physiology ◽  
Crayfish Stretch Receptor ◽  
Touch Sensitivity ◽  
Round Worm ◽  
Touch Sensation

“Mechanoreceptors and touch” is the fifth chapter of the book Sensory Transduction and describes general mechanisms of touch sensitivity in animals. It begins with a review of mechanoreception in the single-celled protozoan Paramecium and transduction of touch in the round worm Caenorhabditis elegans. A thorough treatment is next given of the crayfish stretch receptor and insect mechanoreceptors, including a description of NOMPC channels in Drosophila. The chapter then reviews the anatomy and physiology of mechanoreceptors and touch in mammals, both in glabrous and hairy skin. It concludes with recent discoveries of the molecular biology and physiology of Merkel cells, known to be responsible for much of mammalian touch sensation.

scholarly journals Effects of Lithium on Different Membrane Components of Crayfish Stretch Receptor Neurons

1968 ◽  
Vol 51 (5) ◽  
pp. 635-654 ◽  
Author(s):  
Shosaku Obara ◽  
Harry Grundfest
Keyword(s):  
Significant Role ◽  
Specific Effect ◽  
Stretch Receptor ◽  
Receptor Neuron ◽  
Generator Potential ◽  
Crayfish Stretch Receptor ◽  
Soma Membrane ◽  
Receptor Neurons ◽  
Membrane Components

Unlike several other varieties of input membrane, that of the crayfish stretch receptor develops a generator potential in response to stretch when all the Na of the medium is replaced with Li. However, Li depolarizes the receptor neuron, the soma membrane becoming more depolarized than that of the axon. During exposure to Li the cell usually fires spontaneously for a period, and when it becomes quiescent spike electrogenesis fails in the soma but persists in the axon. These effects are seen in the rapidly adapting as well as the slowly adapting cells. The block of spike electrogenesis of the soma membrane is only partly due to the Li-induced depolarization and a significant role must be ascribed to a specific effect of Li.

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