Reflexentladungen der tiefspinalen Katze durch afferente Impulse aus hochschwelligen nociceptiven A-Fasern (post δ-Fasern) und aus nociceptiven C-Fasern cutaner Nerven

Koll, Werner; Haase, J.; Schütz, Rudolf-M.; Mühlberg, B.

doi:10.1007/bf00363015

Cited by 24 publications

(3 citation statements)

References 15 publications

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“…In two of these a C volley in the SU nerve produced a discharge at a latency of about 200 msec. This observation is in accordance with the occurrence of ventral root reflexes upon C volleys in cutaneous nerves (Koll et al 1961;Franz & Iggo, 1968; W. J&nig & M. Zimmermann, unpublished observations). One of the two C responsive motoneurones was a PBST motoneurone, thus the C fibres evoked a flexor reflex.…”

Section: A and C Fibre Responses In Spinal Neurones 565supporting

confidence: 87%

Characteristics of spinal neurones responding to cutaneous myelinated and unmyelinated fibres*

Gregor¹,

Zimmermann²

1972

The Journal of Physiology

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SUMMARY1. Spike discharges were recorded from neurones in the lumbar spinal cord in cats anaesthetized by barbiturate.2. The neurones were examined systematically for various physiological parameters and for their location. Especially the neurones situated in the dorsal horn were classified for the following parameters: mono-or polysynaptic linkage to myelinated afferents; type of natural stimuli which excited the neurones; depth from the cord surface; number of impulses discharged upon a cutaneous A fibre stimulus; steady-state discharge in the absence of intentional stimulation.3. All neurones were also tested as to whether or not they responded to volleys in cutaneous C fibres. Of 111 units which were activated by the A fibres in nerves from the hairy skin, 57 (= 51 %) responded to C volleys in those nerves too.4. By blocking conduction in the A fibres using polarizing currents it was shown that the responses to C fibre volleys were partially or totally suppressed by a preceding discharge of the neurone in response to an A volley. Using search stimuli which were suprathreshold for C fibres one cell out of 36 could be found which responded only to afferent volleys in C fibres.5. About half of all neurones were shown to be connected monosynaptically to cutaneous A fibres, as was judged from the synaptic delay. The other half were polysynaptically linked to the A fibres. Both monoand polysynaptic neurones were found in all layers of the dorsal horn.

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Section: A and C Fibre Responses In Spinal Neurones 565supporting

confidence: 87%

Characteristics of spinal neurones responding to cutaneous myelinated and unmyelinated fibres*

Gregor¹,

Zimmermann²

1972

The Journal of Physiology

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“…The underlying excitatory state can be built up most readily by a series of weak electrical or mechanical stimuli. It is well known that a characteristic feature of the C reflex is a substantial increase of the discharge by summation of afferent volleys (Koll, Haase, Schutz, and Muhlberg, 1961), and that even very weak natural stimuli tend to give rise to repetitive C fibre activity (Zotterman, 1939). Afferent C fibres may thus be presumed to be involved in the late extensor activity, even though it is of too short latency to be a pure C fibre response.…”

Section: Lennart Grimbymentioning

confidence: 99%

Pathological plantar response. I. Flexor and extensor components in early and late reflex parts.

Grimby¹

1965

Journal of Neurology, Neurosurgery & Psychiatry

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“…5, a clear distinction between the two fibre types was a consistent finding in individual preparations. Therefore, the ability to block myelinated axons by temperatures that do not significantly impair conduction of single impulses in non-myelinated axons provides a valid and useful technique of differential block by cooling (Koll et al 1961). It should be emphasized, however, that variation among preparations makes it necessary to monitor the stage of block for certain separation of the two groups.…”

Section: Conduction Block In Cooled Axonsmentioning

confidence: 99%

Conduction failure in myelinated and non‐myelinated axons at low temperatures

Franz¹,

Iggo²

1968

The Journal of Physiology

246

126

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SUMMARY1. The effects of low temperature on conduction in single myelinated and non-myelinated axons of the feline saphenous nerve were examined and compared. Nerves were cooled by a conventional thermode, but thermal gradients were minimized by an insulating layer of agar-saline gel over the nerve and the face of the thermode.2. The mean blocking temperature of thirty-one non-myelinated axons, 2 7°C, was significantly lower than that of 111 myelinated axons, 7.2 C. No evidence for a differential block of myelinated axons according to their normal conduction velocity could be demonstrated.3. Reductions in the proportional conduction velocities of both myelinated and non-myelinated axons were nearly identical between 17 and 370 C. However, below 17°C the rate at which the proportional conduction velocity of the non-myelinated axons fell during cooling was significantly less than for the myelinated axons and was sufficient to account for their lower blocking temperatures. As a result, critical minimum conduction velocities were reached at higher temperatures in myelinated axons than in non-myelinated axons.4. The conduction velocity of successive impulses in a train slowed progressively to a constant value which depended on the frequency of stimulation. Consequently, the early impulses were separated by intervals that exceeded those between stimuli and were not affected by temperatures that blocked later impulses. The pattern of block was consistent with an increasing refractoriness of the axons as the temperature fell.5. The maximal frequency of discharge that myelinated axons could carry at temperatures between normal and 120 C was related directly to fibre size. Non-myelinated axons could conduct low frequency trains of * Present address:

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Reflexentladungen der tiefspinalen Katze durch afferente Impulse aus hochschwelligen nociceptiven A-Fasern (post δ-Fasern) und aus nociceptiven C-Fasern cutaner Nerven

Cited by 24 publications

References 15 publications

Characteristics of spinal neurones responding to cutaneous myelinated and unmyelinated fibres*

Characteristics of spinal neurones responding to cutaneous myelinated and unmyelinated fibres*

Pathological plantar response. I. Flexor and extensor components in early and late reflex parts.

Conduction failure in myelinated and non‐myelinated axons at low temperatures

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