The retinal spreading depression: A model for nonlinear behavior of the brain

Hanke, Wolfgang; Goldermann, M.; Brand, Sabine; Lima, Vera Maura Fernandes de

doi:10.1007/bfb0104966

Cited by 9 publications

(5 citation statements)

References 18 publications

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“…Our present results complement the previous one obtained using animal neuronal tissues and reveal that plant APs are gravity-sensitive in the same manner as already reported for animal APs 5 6 . We can conclude that APs in root tissues of higher plants and neuronal tissues of animals are gravity-dependent.…”

Section: Discussionsupporting

confidence: 92%

“…Fast gravity perceiving systems, when the perception of a changing acceleration is rapidly transduced into electrical signals, have been documented from unicellular organisms 4 up to neuronal tissues 5 6 . In plants, numerous studies indicate that cell membranes, membrane proteins and membrane potentials are involved in the perception of gravity 7 8 9 .…”

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confidence: 99%

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The Electrical Network of Maize Root Apex is Gravity Dependent

Masi

Ciszak

Comparini

et al. 2015

Sci Rep

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Investigations carried out on maize roots under microgravity and hypergravity revealed that gravity conditions have strong effects on the network of plant electrical activity. Both the duration of action potentials (APs) and their propagation velocities were significantly affected by gravity. Similarly to what was reported for animals, increased gravity forces speed-up APs and enhance synchronized electrical events also in plants. The root apex transition zone emerges as the most active, as well as the most sensitive, root region in this respect.L ife on Earth has evolved under omnipresent and stable gravity forces which act on all living organisms of the planet. Such a permanent physical stimulus, influencing both growth and behaviour, has led to the evolution of gravity perceiving systems in almost any organism. This is true also in plants, where gravitropism plays a central role in the whole plant life cycle (see for example refs. 1-3).Fast gravity perceiving systems, when the perception of a changing acceleration is rapidly transduced into electrical signals, have been documented from unicellular organisms 4 up to neuronal tissues 5,6 . In plants, numerous studies indicate that cell membranes, membrane proteins and membrane potentials are involved in the perception of gravity [7][8][9] . Typically, organismal responses to this environmental stimulus involve the modulation of the cell bioelectrical properties 10,11 . Numerous genes are up-and down-regulated in roots of plants exposed to microgravity [12][13][14] . In addition, roots exposed to microgravity change some of their behavioural features such as their responses to electric fields and light 15,16 . However, inherent root behaviour patterns, such as circumnutations and waving/skewing when grown on the agar plates, have turned out to be gravity-independent [17][18] .In animals, the properties of action potentials (APs) have been also found to be gravity-dependent. Experiments with isolated nerve fibres 19 and muscles 20 showed gravity-sensitive APs. For example, their propagation velocities and the frequency of their generation increased under hypergravity and decreased under microgravity conditions compared to the ground control. Alterations in ion channel permeability due to changes in gravity may be involved in these responses 21,22 , indicating that gravity detection might be an intrinsic property of biological membranes and/or of their ion channels.In higher plants, measurements of electrical potentials under gravistimulation (applying a rotation of 90u to the plant body) have been accomplished since the last century 23 . There is substantial evidence that the reorientation of plants in the gravity field induces a transient electrical activity (the so-called ''geoelectric effect'') (for a review see ref. 24). More recently, a number of investigations on the effect of gravity change on single cells, shoot and roots of plants have been performed. For example, fast changes (up to 17 mV) in surface potentials following gravitropic stimulation have bee...

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Section: Discussionsupporting

confidence: 92%

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confidence: 99%

The Electrical Network of Maize Root Apex is Gravity Dependent

Masi

Ciszak

Comparini

et al. 2015

Sci Rep

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“…Details of the optical recording apparatus have been elsewhere published. 19 The lenses were dissected from the anterior chambers in four experiments and the anterior chamber was left intact in another two. The intact anterior chamber was also glued to a Petri dish.…”

Section: Eye Preparationmentioning

confidence: 99%

Spectral dependence of the intrinsic optical signal of excited states of central gray matter and conformational changes at membrane interfaces

Lima¹,

Weimer

Hanke

2002

Phys. Chem. Chem. Phys.

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“…Sequence of spirals in retinas have been observed [ 25 ] and studied in detail [ 8 , 26 , 27 ]. Their existence was predicted by Bures in 1968 and demonstrated experimentally in 1983 [ 28 ].…”

Section: Electrochemical Waves and Patterns And Their Perceptual mentioning

confidence: 99%

Relevance of Excitable Media Theory and Retinal Spreading Depression Experiments in Preclinical Pharmacological Research

Lima

Hanke

2014

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In preclinical neuropharmacological research, molecular, cell-based, and systems using animals are well established. On the tissue level the situation is less comfortable, although during the last decades some effort went into establishing such systems, i.e. using slices of the vertebrate brain together with optical and electrophysiological techniques. However, these methods are neither fast, nor can they be automated or upscaled. By contrast, the chicken retina can be used as a suitable model. It is easy accessible and can be kept alive in vitro for hours up to days. Due to its structure, in addition the retina displays remarkable intrinsic optical signals, which can be easily used in experiments. Also to electrophysiological methods the retina is well accessible. In excitable tissue, to which the brain and the retina belong, propagating excitation waves can be expected, and the spreading depression is such a phenomenon. It has been first observed in the forties of the last century. Later, Martins-Ferreira established it in the chicken retina (retinal spreading depression or RSD). The electrophysiological characteristics of it are identical with those of the cortical SD. The metabolic differences are known and can be taken into account. The experimental advantage of the RSD compared to the cortical SD is the pronounced intrinsic optical signal (IOS) associated with the travelling wave. This is due to the maximum transparency of retinal tissue in the functional state; thus any physiological event will change it markedly and therefore can be easily seen even by naked eye. The theory can explain wave spread in one (action potentials), two (RSDs) and three dimensions (one heart beat). In this review we present the experimental and the excitable media context for the data interpretation using as example the cholinergic pharmacology in relation to functional syndromes. We also discuss the intrinsic optical signal and how to use it in pre-clinical research.

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The retinal spreading depression: A model for nonlinear behavior of the brain

Cited by 9 publications

References 18 publications

The Electrical Network of Maize Root Apex is Gravity Dependent

The Electrical Network of Maize Root Apex is Gravity Dependent

Spectral dependence of the intrinsic optical signal of excited states of central gray matter and conformational changes at membrane interfaces

Relevance of Excitable Media Theory and Retinal Spreading Depression Experiments in Preclinical Pharmacological Research

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