- Title Pages
- Preface
- Acknowledgements
- Contributors
- Abbreviations
- 1 The cytoskeleton of the squid giant axon
- 2 The nervous system of <i>Loligo pealei</i> provides multiple models for analysis of organelle motility
- 3 Cyclic nucleotide homeostasis and axonal G proteins in the squid <i>Loligo forbesi</i>
- 4 The detection and properties of electrogenic Na<sup>+</sup>–K<sup>+</sup> transport in the squid axon membrane
- 5 Resting And Active K<sup>+</sup> Channels In The Squid Axon Membrane
- 6 Studies of the kinetics of the ionic and gating currents in the axons of <i>Loligo forbesi</i> as a guide to modelling of the sodium channel
- 7 An improved voltage clamp for gating current recording from the squid giant axon
- 8 Voltage Dependence of Sodium Channel Inactivation In The Squid Giant Axon
- 9 Tetrodotoxin affects sodium gating current in squid giant axon
- 10 Single-channel properties and gating of Na<sup>+</sup> and K<sup>+</sup> channels in the squid giant axon
- 11 The effects of internal Ca<sup>2+</sup> and Mg<sup>2+</sup> on ion channels in the squid giant axon
- 12 Anaesthetics, Convulsants, And The Squid Axon Membrane
- 13 Control of the spatial distribution of sodium channels in the squid giant axon and its cell bodies
- 14 Electrophysiology of squid Schwann cells
- 15 The pharmacology of receptors present on squid giant axon Schwann cells
- 16 Periaxonal ion regulation in the squid
- 17 Synaptic transmission in the squid stellate ganglion
- 18 Multiple calcium signalling pathways in squid giant presynaptic terminals
- 19 Chemical transmission at the squid giant synapse
- 20 The structure and physiology of cephalopod muscle fibres
- 21 Organization of cephalopod chromatophore systems: a neuromuscular image-generator
- 22 Neurotransmitters of squid chromatophores
- 23 Diffusion properties of the microenvironment of cephalopod brain
- 24 Cephalopod brains: promising preparations for brain physiology
- 25 Intracellular recordings from the chromatophore lobes of <i>Octopus</i>
- 26 Multiple matrices in the memory system of <i>Octopus</i>
- 27 A novel occluding junction forms the blood–brain barrier in cephalopod molluscs
- 28 Cerebrovascular organization and dynamics in cephalopods
- 29 Squid rhodopsin
- 30 The firefly squid, <i>Watasenia scintillans</i>, has three visual pigments
- 31 The statocysts of cephalopods
- 32 Physiology of squid olfaction
- Index
Diffusion properties of the microenvironment of cephalopod brain
Diffusion properties of the microenvironment of cephalopod brain
- Chapter:
- 23 Diffusion properties of the microenvironment of cephalopod brain
- Source:
- Cephalopod Neurobiology
- Author(s):
Charles Nicholson
Jaleel A. Miyan
Katherine T. Potter
Roddy Williamson
N. Joan Abbott
- Publisher:
- Oxford University Press
The diffusion characteristics of brain extracellular space can be summarized by two parameters, the tortuosity (λ) and the volume fraction (α). Volume fraction is a measure of the volume of extracellular space relative to whole tissue volume, while tortuosity measures the extent to which diffusion is hindered by cellular obstruction in comparison to a free medium. By using local iontophoresis of tetramethylammonium from a micropipette in conjunction with suitable ionselective microelectrodes, λ and α can be determined. The λ and α in an invertebrate neural mass is measured in this chapter to determine whether the parameters had similar values to those previously found in vertebrates. The cephalopod vertical lobe and optic lobes were chosen because of their size and accessibility. The average value of the diffusion parameters in the vertical lobe of intact anaesthetized Sepia (cuttlefish), intact anaesthetized Eledone (octopus), and isolated slices of Sepia were λ = 1.65 and α = 0.10. In isolated slices from the optic lobes of Sepia the average values were λ = 1.86 and α = 0.29. These data suggest that while there may be definite structural differences between the two neural lobes of these cephalopods, the diffusion characteristics are quite similar to those in vertebrates.
Keywords: Cephalopod, volume fraction, iontophoresis, tetramethylammonium, micropipette, Sepia, Eledone
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- Title Pages
- Preface
- Acknowledgements
- Contributors
- Abbreviations
- 1 The cytoskeleton of the squid giant axon
- 2 The nervous system of <i>Loligo pealei</i> provides multiple models for analysis of organelle motility
- 3 Cyclic nucleotide homeostasis and axonal G proteins in the squid <i>Loligo forbesi</i>
- 4 The detection and properties of electrogenic Na<sup>+</sup>–K<sup>+</sup> transport in the squid axon membrane
- 5 Resting And Active K<sup>+</sup> Channels In The Squid Axon Membrane
- 6 Studies of the kinetics of the ionic and gating currents in the axons of <i>Loligo forbesi</i> as a guide to modelling of the sodium channel
- 7 An improved voltage clamp for gating current recording from the squid giant axon
- 8 Voltage Dependence of Sodium Channel Inactivation In The Squid Giant Axon
- 9 Tetrodotoxin affects sodium gating current in squid giant axon
- 10 Single-channel properties and gating of Na<sup>+</sup> and K<sup>+</sup> channels in the squid giant axon
- 11 The effects of internal Ca<sup>2+</sup> and Mg<sup>2+</sup> on ion channels in the squid giant axon
- 12 Anaesthetics, Convulsants, And The Squid Axon Membrane
- 13 Control of the spatial distribution of sodium channels in the squid giant axon and its cell bodies
- 14 Electrophysiology of squid Schwann cells
- 15 The pharmacology of receptors present on squid giant axon Schwann cells
- 16 Periaxonal ion regulation in the squid
- 17 Synaptic transmission in the squid stellate ganglion
- 18 Multiple calcium signalling pathways in squid giant presynaptic terminals
- 19 Chemical transmission at the squid giant synapse
- 20 The structure and physiology of cephalopod muscle fibres
- 21 Organization of cephalopod chromatophore systems: a neuromuscular image-generator
- 22 Neurotransmitters of squid chromatophores
- 23 Diffusion properties of the microenvironment of cephalopod brain
- 24 Cephalopod brains: promising preparations for brain physiology
- 25 Intracellular recordings from the chromatophore lobes of <i>Octopus</i>
- 26 Multiple matrices in the memory system of <i>Octopus</i>
- 27 A novel occluding junction forms the blood–brain barrier in cephalopod molluscs
- 28 Cerebrovascular organization and dynamics in cephalopods
- 29 Squid rhodopsin
- 30 The firefly squid, <i>Watasenia scintillans</i>, has three visual pigments
- 31 The statocysts of cephalopods
- 32 Physiology of squid olfaction
- Index
