Tensile and Compressive Responses of Nociceptors in Rat Hairy Skin

Khalsa, Partap S.; LaMotte, Robert H.; Grigg, Peter

doi:10.1152/jn.1997.78.1.492

Cited by 49 publications

(82 citation statements)

References 38 publications

(9 reference statements)

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“…In our study, 3D strain tracking was incorporated with neurophysiological recordings. Other studies on mechanosensitive afferents have suggested that the correlation between nerve response and local stress was better than local strain in skin [11,16] and knee joint [8,15]. High coefficients were observed in both strain correlation and load correlation with neural responses in current study.…”

Section: Discussionsupporting

confidence: 58%

“…All 2D stress studies with neurophysiology have been performed in vitro on clearly isolated and easily accessible tissues, such as skin [16] and limb muscle [9]. However, because spine FJCs are small and hard to access in vivo, it is rather difficult to accommodate multiple load cells, which are required to measure 2D stress during tensile tests.…”

Section: Discussionmentioning

confidence: 99%

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Development of an in vivo method to investigate biomechanical and neurophysiological properties of spine facet joint capsules

et al. 2005

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IntroductionThe human spine provides substantial load-bearing capability and range of motion due to important properties of its tissues and structures. Among various spinal soft tissues, facet joint capsules (FJC) have been the focus of several research studies due to their important roles in physical activities and spine pathology. The vertebral column has a greater range of motion in the cervical and lumbar regions than in the thoracic region for flexion and extension, and the FJC may experience large mechanical deformation in these regions. Various biomechanical studies have implicated that the lower cervical FJC can stretch beyond their physiologic range under whiplash loading conditions [7,18,28]. Yang and King [30] observed that the lumbar facet joint under compression could cause the capsule to stretch. Clinically, facet denervation has long been employed in the management of cervical, thoracic and low-back pain [4,17,22,24 Abstract Facet joint capsules (FJC) may experience large mechanical deformation under spine motion. There has been no previous quantitative study of the relationship between capsular strain and sensory nerve activation in spine FJC in vivo. Space limitation in the cervical spine makes such a study difficult, as the facet joint must be loaded while simultaneously monitoring nerve discharge from nerve roots immediately adjacent to the loaded tissue. A new methodology was developed to investigate biomechanical and neurophysiological properties of spine facet joint capsules in vivo. The method incorporated a custom-fabricated testing frame for facet joint loading, a stereoimaging system, and a template-matching technique to obtain single afferent response. It was tested by loading goat C5-C6 FJC in vivo with simultaneous nerve root recordings and 3D strain tracking of the capsules. Preliminary data showed that 18 of 23 afferents (78.3%) were found to be mechanosensitive to tensile stretch, and five were not responsive, even under tensile load as high as 27.5 N. Mechanosensitive afferents in goat capsules had tensile strain thresholds of 0.119±0.080. Neural responses of all mechanosensitive units showed statistically significant correlations (all P<<0.05) with both capsular load (r 2 =0.744±0.109) and local strain (r 2 =0.868±0.088). This method enables the investigation of the correlation between tissue load, deformation and neural responses of mechanoreceptors in spine facet joint capsules, and can be adapted to investigate tissue loading and neural response of other soft tissues.

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Section: Discussionsupporting

confidence: 58%

Section: Discussionmentioning

confidence: 99%

Development of an in vivo method to investigate biomechanical and neurophysiological properties of spine facet joint capsules

et al. 2005

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“…At these hot spots, the stimulus-response functions of C-fiber nociceptors reached a plateau at force levels substantially below the pain threshold (Greenspan and McGillis, 1991;Khalsa et al, 1997;Andrew and Greenspan, 1999;Slugg et al, 2000). The flatness of the stimulus-response curves suggested that C-fiber nociceptors could not encode painfulness of punctate mechanical stimuli.…”

Section: Stimulus-response Functions and Psychophysical Correlationsmentioning

confidence: 99%

The Population Response of A- and C-Fiber Nociceptors in Monkey Encodes High-Intensity Mechanical Stimuli

Slugg¹,

Campbell²,

Meyer³

2004

J. Neurosci.

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The peripheral neural mechanism of pain to mechanical stimuli remains elusive. C-fiber nociceptors do not appear to play a major role in mechanical pain sensation, because the stimulus-response function of mechanically sensitive C-fiber nociceptors to punctate mechanical stimuli applied to the most sensitive region in the receptive field (the hot spot) reaches a plateau at force levels insufficient to produce pain in humans. However, studies at the hot spot give an incomplete understanding of the inputs of nociceptors to the spinal cord. To estimate how the population of nociceptors responds to a punctate stimulus, it is necessary to know how the response varies with the position within the receptive field. For A-fiber and C-fiber nociceptors, we systemically measured the response to a 100 m wide blade stimulus as a function of position in the receptive field at different force levels. Highly reproducible receptive field response maps that contained multiple peaks and valleys were obtained. Some peaks were only 100 m wide. As force increased, the response and width of the peaks increased, the response in valleys increased, and new peaks appeared. The averaged response across the map provides an estimate of the population response and was found to increase monotonically with force over a large stimulus range for both A-fiber and C-fiber nociceptors. These data provide evidence that both C-fiber and A-fiber nociceptors may encode high-intensity mechanical stimuli.

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“…Because the preparation of rat skin (Khalsa et al 1997) and the apparatus (Del Prete et al 2003) are described in detail elsewhere, they are only briefly described here.…”

Section: E T H O D Smentioning

confidence: 99%

Stretch Sensitivity of Cutaneous RA Mechanoreceptors in Rat Hairy Skin

Robichaud

Prete

Grigg

2003

Journal of Neurophysiology

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Robichaud, Daniel R. II, Zaccaria Del Prete, and Peter Grigg. Stretch sensitivity of cutaneous RA mechanoreceptors in rat hairy skin. J Neurophysiol 90: 2065-2068, 2003. First published June 4, 2003 10.1152/jn.00405.2003. Twenty-five rapidly adapting mechanoreceptor afferents were recorded in an in vitro preparation of rat skin and nerve. Single units were recorded while the skin was subjected to dynamic uniaxial stretch using a pseudo-Gaussian noise (PGN) input waveform. Force was the controlled variable in stretch stimuli. Measured loads and displacements were used to calculate tensile stresses, strains, and their rates of change. Associations between spike responses and individual stimulus components such as tensile stress or strain were determined in a reverse correlation design using multiple logistic regression. Spikes were strongly associated with stress, at memory times from 0 to 14 ms, and with the rate of change of stress, at a memory times between 6 and 18 ms. There was a strong interaction between stress and its rate of change, with a maximum value at a memory time of 10 ms. We found no relationship between spike responses and strain. I N T R O D U C T I O NIt is well known that many cutaneous mechanoreceptor afferents can be activated by stretch stimuli (Del Prete et al. 2003;Grigg 1996;Grigg and Hoffman 1996;Kumazawa and Perl 1977; Nordin 1994). However, stretching skin produces a number of mechanical states, such as tensile stress, tensile strain, strain energy density, and their rates of change, in the skin. In general, it has been unclear which of these states might act as the stimulus to the mechanoreceptor ending. Recently, however, several of us (Del Prete et al. 2003) described a method that allows for determining the association between spikes and multiple stimulus variables. This method, which is based on multiple logistic regression (Hosmer and Lemeshow 1989), also allows for determining whether there are memory effects in the association between variables and spikes. "Memory," in this sense, refers to the time between the production of a stimulus in the skin and the appearance of a response in the afferent.The use of logistic regression in applications such as this has been described in detail with reference to mechanoreceptors from mouse skin (Del Prete et al. 2003). In addition, the method was used to re-analyze previously published data from rapidly adapting (RA) afferents in rat skin (Grigg and Del Prete 2002). In both preparations, spikes were strongly associated with the rate of change of tensile stress. However, the two experiments found differences in the memory times at which the effect of that stimulus was observed. Responses in mouse mechanoreceptors were most strongly associated with the rate of change of stress 8 -10 ms before a spike. In contrast, the re-analyzed data from rat skin units showed that the rate of change of stress had its maximal effect on the order of 30 ms prior to a spike. In attempting to account for the differences between these two results, we note that...

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Tensile and Compressive Responses of Nociceptors in Rat Hairy Skin

Cited by 49 publications

References 38 publications

Development of an in vivo method to investigate biomechanical and neurophysiological properties of spine facet joint capsules

Development of an in vivo method to investigate biomechanical and neurophysiological properties of spine facet joint capsules

The Population Response of A- and C-Fiber Nociceptors in Monkey Encodes High-Intensity Mechanical Stimuli

Stretch Sensitivity of Cutaneous RA Mechanoreceptors in Rat Hairy Skin

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