Sympathetic effects on C-fibre kesponses

Shyu, Bai-Chuang; Huang, Kuo-Chin; Rydenhag, Bertil; Andersson, Staffan

doi:10.1016/0304-3959(84)90144-1

Cited by 3 publications

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“…T h e aim of this study was to investigate if stimulation of sympathetic fibres could influence the responsiveness of the primary afferent nerve fibres in normal intact peripheral nerves. Preliminary reports of this study have been presented previously (Shyu et al 1984, Shyu & Anderson 1987.…”

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confidence: 91%

Effects of sympathetic stimulation on C‐fibre responses in rabbit

Shyu

Olausson

Huang

et al. 1989

Acta Physiologica Scandinavica

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Unmyelinated C-fibre responses to electrical stimulation were recorded in common peroneal, sural and tibial nerves of rabbits. Three distinct C elevations, here called C1, C2 and C3, were recorded. C2 is probably of somatic origin because it was depressed due to collision by peripheral stimulation of cutaneous receptors. The conduction velocity of C3 corresponded to that of sympathetic post-ganglionic fibres. During sympathetic trunk stimulation the A-fibre responses were not significantly changed while C responses, especially C2, were reduced in amplitude and slightly delayed. The C-fibre responses were also influenced by intra-arterial infusion of noradrenaline. In most cases, the latency of the response was increased. The effect of sympathetic stimulation was completely blocked by hexamethonium, and partly blocked by phentolamine, an adrenergic alpha-receptor blocking agent which also blocked the effect of noradrenaline. The findings suggest that there are adrenergic receptors distributed along unmyelinated somatic afferent fibres. Sympathetic activity may release noradrenaline in the peripheral nerve, resulting in changed conductive properties in unmyelinated fibres transmitting sensory information.

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confidence: 91%

Effects of sympathetic stimulation on C‐fibre responses in rabbit

Shyu

Olausson

Huang

et al. 1989

Acta Physiologica Scandinavica

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“…P-lipotropin. and adrenocorticotropic hormone in blood (2.3.10)and to elevate the pain threshold for about one hour (7,30,32). According to our knowledge, a permanent elevation of the pain threshold due to increase of motor activity or aerobic capacity has not yet (12,21).…”

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confidence: 99%

Physical Activity and Fitness in Patients with Headache Disorders*

Neumann²,

Bj³

et al. 1997

Int J Sports Med

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Recent studies indicate that aerobic activities might reduce severity and/or frequency of migraine attacks. The present study was intended to investigate whether physical activities and fitness (aerobic endurance, flexibility, and muscle strength endurance) as well as body composition are different in patients with headache disorders and healthy control subjects. The study included 56 patients (aged 17-64 years) with headache disorders (migraine, tension-type, cluster, analgetics abuse, and other types of headache) and 145 age-matched volunteers without history of recurrent or chronic headache. A standardized questionnaire revealed similar self-esteem of physical activities in both groups. Objective physical fitness testing in a representative sample of 22 patients and 36 control subjects showed significantly reduced aerobic endurance in female and male patients as well as reduced flexibility in female patients as compared to control subjects, whereas muscle strength endurance was not significantly different between both groups. Female patients presented with a significantly higher total body fat as compared to control subjects. In conclusion, headache patients turned out to be less physically fit than control subjects. There was a discrepancy between self-esteem and objective test results regarding physical activity and fitness in patients with headache disorders.

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Pain management: physiopathology, future research and endpoints

Sosnowski

1993

Support Care Cancer

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In this article, first, the different stages of acquisition and processing of nociceptive information from peripheral receptor to brain are reviewed and the plastic changes that accompany tissue injury are underlined. For instance, the subclassification of peripheral receptors in nociceptors and non-nociceptors (e.g., mechanoreceptors, thermoreceptors) must be understood in the light of peripheral sensitization. This phenomenon is the probable explanation for primary hyperalgesia, the decrease in pain threshold at the site of injury. The observation that substance P enhances N-methyl-D-aspartate (NMDA)-elicited responses suggests that these two receptors may operate in concert to prolong and amplify the afferent input generated by peripheral tissue injury. Such afferent barrage induces a state of central sensitization. Second, the major problems in the management of cancer pain, i.e. the development of tolerance to opioids and opioid-insensitive pain, are discussed. The loss of drug effect observed after chronic exposure of the opioid receptor (tolerance) may be the consequence of the down-regulation or desensitization phenomenon (where the total number of receptors coupled to the second messenger is reduced). The agonist dose-response begins to shift to the right. The dramatic analgesic improvement obtained with subanaesthetic doses of ketamine, an NMDA receptor antagonist, in those of our cancer patients who have become resistant to morphine is intriguing. As shown for tolerance, insensitivity to opioids may represent a rightward shift in the opioid dose-response curve and the analgesic effect of ketamine the reversal of that shift.

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Sympathetic effects on C-fibre kesponses

Cited by 3 publications

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Effects of sympathetic stimulation on C‐fibre responses in rabbit

Effects of sympathetic stimulation on C‐fibre responses in rabbit

Physical Activity and Fitness in Patients with Headache Disorders*

Pain management: physiopathology, future research and endpoints

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