Membrane potentials in the electroplates of the electric eel

Keynes, R. D.; Martins-Ferreira, H

doi:10.1113/jphysiol.1953.sp004849

Cited by 235 publications

(137 citation statements)

References 25 publications

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“…The anterior surface is rich in Nat, K+, ATPase. The posterior one, which receives the innervation, contains also Nat, K+, ATPase (SOMLO et al, 1977) and is rich in acetylcholine receptors (AChR) (COUCEIRO et al, 1953;CHANGEUX et al, 1969;MEUNIER et al, 1974) and responsible for the discharge (KEYNES and MARTINS-FERREIRA, 1953). Microscopic observations of the electrocyte show that in the syncytium there is a small number of nuclei which are located near the anterior membrane on the extremities of the papillae (COUCEIRO and AKERMAN, 1948).…”

Section: Electrophorusmentioning

confidence: 99%

Desmin and Actin Filaments in Membrane-Cytoskeletal Preparations of the Electric Tissue of Electrophorus electricus, L.

Mermelstein

Benchimol

Taffarel

et al. 1997

Archives of Histology and Cytology

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Section: Electrophorusmentioning

confidence: 99%

Desmin and Actin Filaments in Membrane-Cytoskeletal Preparations of the Electric Tissue of Electrophorus electricus, L.

Mermelstein

Benchimol

Taffarel

et al. 1997

Archives of Histology and Cytology

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“…The medulla and upper spinal cord were exposed from the dorsal side. Respiration was maintained by perfusion through the mouth with physiological saline for Electrophorus (25). The composition of this saline is 169 rnu NaC1, 5 mM KC1, 3 m_u CaCI~, 1.5 mu MgCI~, 1.2 mM Na2HPO~, and 0.3 mM NaH2PO4.…”

Section: E T H O D Smentioning

confidence: 99%

Chemically Mediated Transmission at a Giant Fiber Synapse in the Central Nervous System of a Vertebrate

Auerbach

Bennett

1969

The Journal of General Physiology

124

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The hatchetfish, Gasteropelecus, possesses large pectoral fin adductor muscles whose simultaneous contraction enables the fish to dart upwards at the approach of a predator. These muscles can be excited by either Mauthner fiber. In the medulla, each Mauthner fiber forms axo-axonic synapses on four "giant fibers," two on each side of the midline. Each pair of giant fibers innervates ipsilateral motoneurons controlling the pectoral fin adductor muscles. Mauthner fibers and giant fibers can be penetrated simultaneously by microelectrodes close to the synapses between them. Electrophysiological evidence indicates that transmission from Mauthner to giant fiber is chemically mediated. Under some conditions miniature postsynaptic potentials (PSP's) are observed, suggesting quantal release of transmitter. However, relatively high frequency stimulation reduces PSP amplitude below that of the miniature potentials, but causes no complete failures of PSP's. Thus quantum size is reduced or postsynaptic membrane is desensitized. Ramp currents in Mauthner fibers that rise too slowly to initiate spikes can evoke responses in giant fibers that appear to be asynchronous PSP's. Probably both spikes and ramp currents act on the same secretory mechanism. A single Mauthner fiber spike is followed by prolonged depression of transmission; also PSP amplitude is little affected by current pulses that markedly alter presynaptic spike height. These findings suggest that even a small spike releases most of an immediately available store of transmitter. If so, the probability of release by a single spike is high for any quantum of transmitter within this store. I N T R O D U C T I O NA n i m p o r t a n t p r o b l e m in the study of synapfic transmission is the relation between pre-and postsynaptic potentials. A l t h o u g h this relation has been d e t e r m i n e d in a n u m b e r of instances of electrical transmission (5, 7, 8, 15, ~8 3

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“…The large extension of the surface of the uninnervated membrane that is made possible by the canalicular network might also account (cf. 21) for the very low resistance of the uninnervated surface of torpedine electric fishes (5,8), Astroscopus (6), and Electrophorus (1,24). However, the electroplaques of Rajidae, Malapterurus, and probably also the Mormyridae (29) have canaliculi, though both surfaces of the cells have approxi-…”

Section: Discussionmentioning

confidence: 99%

ELECTRON MICROSCOPIC AND HISTOCHEMICAL COMPARISON OF THE TWO TYPES OF ELECTROPLAQUES OF NARCINE BRASILIENSIS

Wachtel

Mathewson

Grundfest

1961

The Journal of Cell Biology

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The torpedine electric fish Narcine brasiliensis has two morphologically distinct electric organs (main and accessory) which alsodiffer with respect to anumberofelectrophysiological properties. The fine structure of the electroplaques of these organs has been examined by electron microscopy and by a histochemical method for localizing esterase activity with a high degree of resolution. In both kinds of electroplaques the innervated surface (ventral in those of the main organ, dorsal in those of the accessory) is the only site of esterase activity. The latter is further confined to the regions of synaptic contact between vesicle-con taining axon terminals and the electroplaque membrane. The synaptic apparatus is similar to, but less elaborate than, that of neuromuscular junctions. The axon terminals and electroplaque membranes are free of connective tissue envelopments. The membrane of the uninnervated surfaces forms a continuum with a dense canalicular network which penetrates deeply into the 7 # thick electroplaques of the main organ. The canalicular network has about the same thickness in the 20 # electroplaques of the accessory organ. Except for this difference, the two kinds of cells appear to have the same fine structure. This finding is discussed in relation to the electrophysiological data on functional differences.

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Membrane potentials in the electroplates of the electric eel

Cited by 235 publications

References 25 publications

Desmin and Actin Filaments in Membrane-Cytoskeletal Preparations of the Electric Tissue of Electrophorus electricus, L.

Desmin and Actin Filaments in Membrane-Cytoskeletal Preparations of the Electric Tissue of Electrophorus electricus, L.

Chemically Mediated Transmission at a Giant Fiber Synapse in the Central Nervous System of a Vertebrate

ELECTRON MICROSCOPIC AND HISTOCHEMICAL COMPARISON OF THE TWO TYPES OF ELECTROPLAQUES OF NARCINE BRASILIENSIS

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