The site of impulse initiation in a nerve cell of a crustacean stretch receptor

Edwards, Charles; Ottoson, David

doi:10.1113/jphysiol.1958.sp006049

Cited by 159 publications

(54 citation statements)

References 13 publications

(17 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Synaptic activation confined to distal portions of dendrites may be incapable of initiating firing because of the inability of dendrites to conduct propagated impulses (Clare & Bishop, 1955 a, b) coupled with the decrement associated with electrotonic propagation over the long, thin dendritic branches. Under these circumstances, the dendritic response might not be able to depolarize the cell body to the firing level of its trigger zone a, b; Fuortes, Frank & Becker, 1957;Eyzaguirre & Kuffler, 1955;Fatt, 1957b;Edwards & Ottoson, 1958). Alternatively, if dendrites are capable of propagating all-or-none responses (Cragg & Hamlyn, 1955), the lack of discharge may be due simply to an inadequate number or potency of synapses from dorsal root collaterals.…”

Section: Discussionmentioning

confidence: 99%

Potential fields initiated during monosynaptic activation of frog motoneurones

Brookhart¹,

Fadiga²

1960

The Journal of Physiology

View full text Add to dashboard Cite

It has been noted that the patterns of discharge evoked in frog spinal motoneurones are significantly different when a presynaptic volley is initiated in dorsal root fibres and when the excitation arrives over a system of fibres in the lateral column . Anatomical studies (Liu & Chambers, 1957) raise the possibility that the differences may be ascribed to variations in the site of synaptic terminations on the motoneurones or to differences in the number of interneurones involved in the two pathways, or both. The present study was undertaken in order to determine which of these possibilities is the more likely. The technique of focal recording from within the spinal cord, and comparison of the temporal relations of simplified responses, have permitted a test of the hypothesis suggested by anatomical findings. METHODSThe experiments have been performed on isolated spinal cords of frogs (Rana pipiens) during winter and spring months. The arrangement has been similar to that described previously . Micropipettes of 5-15 MQ resistance, filled with potassium citrate, were used for depth recording. Ipsilateral evoked focal potentials were recorded unipolarly through an impedance-matching preamplifier, a high-gain, RC-coupled amplifier (time constant 1 sec), and photographed from an oscilloscope screen. A second oscilloscope was usually used to monitor ipsilateral ventral root responses. A thermistor thermometer in contact with the cord made possible temperature control in the range from 15-17°C.The method of preserving function in isolated dorsal and ventral roots was important to the success of these experiments. The root was extended laterally on a small slip of ifiter paper coated with thinned petroleum jelly. The root was laid over hooked platinum electrodes and a complete covering of petroleum jelly delivered from a syringe and hypodermic needle was built around the entire root. This procedure not only preserved the fibres of the root, but also prevented troublesome electrical instability and provided the necessary insulation of the ventral root from the fluid surrounding the cord. In recording from the ventral root, the distance between proximal lead and cord varied in different experiments from 3 to 5 mm; the distal lead was always applied as far as possible from the cord on the crushed end of the root.

show abstract

Section: Discussionmentioning

confidence: 99%

Potential fields initiated during monosynaptic activation of frog motoneurones

Brookhart¹,

Fadiga²

1960

The Journal of Physiology

View full text Add to dashboard Cite

show abstract

“…Possibly spikes arise at some distance down the axon (cf. Edwards & Ottoson, 1958) and may cause little potential change in the intracellular record.…”

Section: Discussionmentioning

confidence: 99%

Potential changes recorded inside primary afferent fibres within the spinal cord

Eccles¹,

Krnjević²

1959

The Journal of Physiology

130

View full text Add to dashboard Cite

“…However, many studies have shown that action potentials initiate in the proximal axon in diverse invertebrate neurons (including unipolar neurons) from lobster, leech, Aplysia and insects (Edwards and Ottoson, 1958;Tauc, 1962;Goodman and Heitler, 1979;Gu et al, 1991; Melinek and Muller, 1996). Therefore, the ability of the proximal axon to serve as the site of action potential initiation appears to be an ancient shared feature of vertebrate and invertebrate neurons rather than a recent vertebrate innovation.…”

Section: Neuronal Polarity In Model Invertebrate Bilateriansmentioning

confidence: 99%

Neuronal polarity: an evolutionary perspective

Rolls

Jegla

2015

Journal of Experimental Biology

View full text Add to dashboard Cite

Polarized distribution of signaling molecules to axons and dendrites facilitates directional information flow in complex vertebrate nervous systems. The topic we address here is when the key aspects of neuronal polarity evolved. All neurons have a central cell body with thin processes that extend from it to cover long distances, and they also all rely on voltage-gated ion channels to propagate signals along their length. The most familiar neurons, those in vertebrates, have additional cellular features that allow them to send directional signals efficiently. In these neurons, dendrites typically receive signals and axons send signals. It has been suggested that many of the distinct features of axons and dendrites, including the axon initial segment, are found only in vertebrates. However, it is now becoming clear that two key cytoskeletal features that underlie polarized sorting, a specialized region at the base of the axon and polarized microtubules, are found in invertebrate neurons as well. It thus seems likely that all bilaterians generate axons and dendrites in the same way. As a next step, it will be extremely interesting to determine whether the nerve nets of cnidarians and ctenophores also contain polarized neurons with true axons and dendrites, or whether polarity evolved in concert with the more centralized nervous systems found in bilaterians. KEY WORDS: Axon, Dendrite, Axon initial segment, MicrotubuleIntroduction: are vertebrates special because of their neurons?The elaborate behaviors of vertebrates are made possible by the evolution of nervous systems of unparalleled size and complexity. The developmental mechanisms that assemble the vertebrate nervous system and physical mapping of the circuits that underlie behavior are subjects of intense study. But are the neurons of the vertebrate nervous system themselves also unique or special in some way? Do they have vertebrate-only features that facilitate the assembly of large, complex nervous systems? Or is the vertebrate nervous system based on an ancient and highly adaptable neuronal cell type? Understanding the evolutionary history of neurons is critical to understanding how vertebrate nervous systems and behavior came to be. Another very practical reason for asking these questions is that it is helpful to know which features of neurons are shared with and can thus be studied in cheap, efficient invertebrate model systems. Vertebrate-specific neuronal features, in contrast, must be studied in model systems such as zebrafish or mouse, for which time and expense often limit the scientific questions that can be asked.The polarized functional organization of neurons that facilitates assembly of complex circuits might be a good candidate for being associated specifically with vertebrates. Indeed, in a highly cited review on neuronal polarity from 1994, invertebrate neurons are seen as 'sufficiently different' in terms of organization from vertebrate neurons that the polarized sorting mechanisms are suggested to also differ (Craig and Banker, 1994...

show abstract

The site of impulse initiation in a nerve cell of a crustacean stretch receptor

Cited by 159 publications

References 13 publications

Potential fields initiated during monosynaptic activation of frog motoneurones

Potential fields initiated during monosynaptic activation of frog motoneurones

Potential changes recorded inside primary afferent fibres within the spinal cord

Neuronal polarity: an evolutionary perspective

Contact Info

Product

Resources

About