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Patterns of activity-dependent conduction velocity changes differentiate classes of unmyelinated mechano-insensitive afferents including cold nociceptors, in pig and in human.
Pain. 2010 Jan; 148(1):59-69.PAIN

Abstract

Activity-dependent slowing of conduction velocity (ADS) differs between classes of human nociceptors. These differences likely reflect particular expression and use-dependent slow inactivation of axonal ion channels and other mechanisms governing axonal excitability. In this study, we compared ADS of porcine and human cutaneous C-fibers. Extracellular recordings were performed from peripheral nerves, using teased fiber technique in pigs and microneurography in humans. We assessed electrically-induced conduction changes and responsiveness to natural stimuli. In both species, the group of mechano-insensitive C-fibers showed the largest conduction slowing (approximately 30%) upon electrical stimulation (2Hz for 3min). In addition, we found mechano-insensitive cold nociceptors in pig that slowed only minimally (<10% at 2Hz), and a similar slowing pattern was found in some human C-fibers. Mechano-sensitive afferents showed an intermediate conduction slowing upon 2Hz stimulation (pig: 14%, human 23%), whereas sympathetic efferent fibers in pig and human slowed only minimally (5% and 9%, respectively). In fiber classes with more pronounced slowing, conduction latencies recovered slower; i.e. mechano-insensitive afferents recovered the slowest, followed by mechano-sensitive afferents whereas cold nociceptors and sympathetic efferents recovered the fastest. We conclude that mechano-insensitive C-fiber nociceptors can be differentiated by their characteristic pattern of ADS which are alike in pig and human. Notably, cold nociceptors with a distinct ADS pattern were first detected in pig. Our results therefore suggest that the pig is a suitable model to study nociceptor class-specific changes of ADS.

Authors+Show Affiliations

Department of Anesthesiology Mannheim, University of Heidelberg, Germany Department of Neurosurgery, Johns Hopkins University, Baltimore, USA Department of Physiology, University of Erlangen, Germany.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19913997

Citation

Obreja, Otilia, et al. "Patterns of Activity-dependent Conduction Velocity Changes Differentiate Classes of Unmyelinated Mechano-insensitive Afferents Including Cold Nociceptors, in Pig and in Human." Pain, vol. 148, no. 1, 2010, pp. 59-69.
Obreja O, Ringkamp M, Namer B, et al. Patterns of activity-dependent conduction velocity changes differentiate classes of unmyelinated mechano-insensitive afferents including cold nociceptors, in pig and in human. Pain. 2010;148(1):59-69.
Obreja, O., Ringkamp, M., Namer, B., Forsch, E., Klusch, A., Rukwied, R., Petersen, M., & Schmelz, M. (2010). Patterns of activity-dependent conduction velocity changes differentiate classes of unmyelinated mechano-insensitive afferents including cold nociceptors, in pig and in human. Pain, 148(1), 59-69. https://doi.org/10.1016/j.pain.2009.10.006
Obreja O, et al. Patterns of Activity-dependent Conduction Velocity Changes Differentiate Classes of Unmyelinated Mechano-insensitive Afferents Including Cold Nociceptors, in Pig and in Human. Pain. 2010;148(1):59-69. PubMed PMID: 19913997.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Patterns of activity-dependent conduction velocity changes differentiate classes of unmyelinated mechano-insensitive afferents including cold nociceptors, in pig and in human. AU - Obreja,Otilia, AU - Ringkamp,Matthias, AU - Namer,Barbara, AU - Forsch,Elmar, AU - Klusch,Andreas, AU - Rukwied,Roman, AU - Petersen,Marlen, AU - Schmelz,Martin, Y1 - 2009/11/13/ PY - 2009/01/07/received PY - 2009/09/08/revised PY - 2009/10/06/accepted PY - 2009/11/17/entrez PY - 2009/11/17/pubmed PY - 2010/4/8/medline SP - 59 EP - 69 JF - Pain JO - Pain VL - 148 IS - 1 N2 - Activity-dependent slowing of conduction velocity (ADS) differs between classes of human nociceptors. These differences likely reflect particular expression and use-dependent slow inactivation of axonal ion channels and other mechanisms governing axonal excitability. In this study, we compared ADS of porcine and human cutaneous C-fibers. Extracellular recordings were performed from peripheral nerves, using teased fiber technique in pigs and microneurography in humans. We assessed electrically-induced conduction changes and responsiveness to natural stimuli. In both species, the group of mechano-insensitive C-fibers showed the largest conduction slowing (approximately 30%) upon electrical stimulation (2Hz for 3min). In addition, we found mechano-insensitive cold nociceptors in pig that slowed only minimally (<10% at 2Hz), and a similar slowing pattern was found in some human C-fibers. Mechano-sensitive afferents showed an intermediate conduction slowing upon 2Hz stimulation (pig: 14%, human 23%), whereas sympathetic efferent fibers in pig and human slowed only minimally (5% and 9%, respectively). In fiber classes with more pronounced slowing, conduction latencies recovered slower; i.e. mechano-insensitive afferents recovered the slowest, followed by mechano-sensitive afferents whereas cold nociceptors and sympathetic efferents recovered the fastest. We conclude that mechano-insensitive C-fiber nociceptors can be differentiated by their characteristic pattern of ADS which are alike in pig and human. Notably, cold nociceptors with a distinct ADS pattern were first detected in pig. Our results therefore suggest that the pig is a suitable model to study nociceptor class-specific changes of ADS. SN - 1872-6623 UR - https://www.unboundmedicine.com/medline/citation/19913997/Patterns_of_activity_dependent_conduction_velocity_changes_differentiate_classes_of_unmyelinated_mechano_insensitive_afferents_including_cold_nociceptors_in_pig_and_in_human_ DB - PRIME DP - Unbound Medicine ER -