The Neurological Basis for Cardiac Pain
Irving H. Zucker, Joseph P. Gilmore in Reflex Control of the Circulation, 2020
Electrical stimulation of cardiopulmonary afferent fibers generally activates spinothalamic and spinoreticular tract cells of the T1–T5 segments (Ammons et al., 1985a, b; Blair et al., 1981; Foreman et al., 1984). Stimulation at low intensities produces a volley of activity with a latency appropriate for an A-delta fiber input (Fig. 4a). Increasing the intensity and duration of the stimulus adds a later volley with a latency appropriate for a C-fiber input (Fig. 4b). Minimum afferent conduction velocity for these afferent fibers is about 9 m/s for the A-delta peak and about 1.0 m/s for the C-fiber peak. Approximately 50% of the STT and SRT cells receive only Adelta fiber input, 40% receive both A-delta and C-fiber input, and approximately 10% receive only C-fiber input. Electrophysiological determination for the diameter of sympathetic afferent fibers correlates well with anatomical studies (Seagard et al., 1978; Emery et al., 1976, 1978).
The Physiology of Pain
Ronald Schleifer in Pain and Suffering, 2014
The A-delta fiber “sensory discriminative” subsystem “computes the location, intensity, duration, and nature (stabbing, burning, prickling) of the stimuli” while the “‘affective motivational’ subsystem” begins with the C fibers. The two systems of response—with the C-fiber system phylogenetically older—are “similar to the color and form processors in the visual system … [and] remain largely segregated” (Hardcastle 1999: 102–03; phylogeny is the study of evolutionary divergence of species in relation to their common ancestors). Although these physiological facts are widely accepted, the language of “sensory discriminative” vs. “affective motivational” subsystems that Hardcastle uses here is part of her more controversial contention that a physiological rather than a psychological description of pain is more accurate. Nevertheless, there is general acceptance that these two aspects of pain—its sensory location and its motivational feelings—can be dissociated so that only one or the other operates, either by means of natural accidents or drugs, leading people to be able to localize pain sensations without becoming upset by the fact that they are in pain (as in the asymbolia Grahek describes) or, on the contrary, leading them to be able “to have a pain sensation … [while lacking] fine localization and intensity discrimination” (Hardcastle 1999: 104). Finally, the nociceptive centers in the thalamus and cortex can be activated without corresponding activations of A-delta or C fibers in phenomena such as much lower back pain (fully 80 percent of reported back pain is not associated with measurable tissue damage [Hardcastle 1999: 104]) or “phantom limb” pain in missing limbs described in Chapter 3.
Overview of Pain: Classification and Concepts
Mark V. Boswell, B. Eliot Cole in Weiner's Pain Management, 2005
There are thermal patterns of pain, which are probably related to the distribution of sympathetic C-fibers nerves and with sympathetic chain pathway components, without shorting, crossing over, emphatically to the A-delta fiber pathways.
Quantitative Sensory Testing (QST) Estimation of Regional Cutaneous Thermal Sensitivity During Waking State, Neutral Hypnosis, and Temperature Specific Suggestions
Published in International Journal of Clinical and Experimental Hypnosis, 2019
Gianluca Conversa, Enrico Facco, Matteo Luigi Giuseppe Leoni, Michelangelo Buonocore, Rosa Bagnasco, Lucia Angelini, Laura Demartini, David Spiegel
Thermal sensitivity was checked using the QST (SenseLab msa; Somedic Horby, Sweden). QST is a noninvasive, pain-free technique allowing measurement of thresholds for four sensory submodalities: a) C fiber-mediated warm threshold (usually at 1- 2ºC above adaptation temperature in normal subjects); b) A-delta fiber-mediated cold sensation (usually at 1- 2ºC below adaptation temperature in normal subjects); c) heat pain threshold (at about 45ºC in normal subjects, mostly mediated by C fibers with some involvement of A-delta fibers); d) cold pain threshold (at about 10ºC but with higher variability with respect to the other modalities and dependent on both C and A-delta fiber stimulation). The equipment includes a thermal stimulator—able to deliver extremely fast stimuli from baseline temperature to 55ºC in less than 250 ms (i.e., a rapid rise in temperature at a rate of 70ºC/sec)—as well as a solid-state thermoelectric cooler (Peltier element) and a temperature-controlled algorithm sampling temperature at a rate of 200 times per second.
Intracarpal midazolam: does it offer better pain relief than dexamethasone in carpal tunnel syndrome patients? A randomized double-blind clinical trial
Published in Egyptian Journal of Anaesthesia, 2022
Mina Maher Raouf, Mohammad Awad Alsaeed, Manal Hassanien, Esraa A Talaat, Tamer Elzaem Esmael, Emad Zarief Kamel
On the other hand, midazolam, which is a short-acting benzodiazepine could possess its analgesic effects through gamma-aminobutyric acid (GABA-A) receptors stimulation found on the peripheral nerve [7,8]. Midazolam also was found to reduce C-fiber evoked activity. Kontinen and Dickenson in an animal study described that administration of midazolam 0.1–3.0 mg/kg subcutaneously reduced the A delta-fiber evoked activity in all studied groups, but the C-fiber evoked activity was reduced significantly only in the spinal nerve ligation group where neuropathic pain has been induced [9].
Related Knowledge Centers
- Axon
- Cable Theory
- Nerve Conduction Velocity
- Proprioception
- Sensory Neuron
- Myelin
- Group B Nerve Fiber
- Group C Nerve Fiber
- Type Ia Sensory Fiber
- Type II Sensory Fiber