Author, as appears in the article.: Margalef R, Sisquella M, Bosque M, Romeu C, Mayoral O, Monterde S, Priego M, Guerra-Perez R, Ortiz N, Tomàs J, Santafe M

Department: Ciències Mèdiques Bàsiques Medicina i Cirurgia

URV's Author/s: Monterde Pérez, Sonia / Ortiz Castellón, Nicolau Antoni / Santafé Martínez, Manuel

Keywords: Spontaneous acetylcholine release Myofascial trigger point Myofascial pain syndrome Endplate noise Animal model myofascial trigger point myofascial pain syndrome endplate noise animal model

Abstract: Myofascial pain syndrome is one of the most common forms of muscle pain. In this syndrome, pain is originated by the so-called trigger points, which consists of a set of palpable contraction knots in the muscle. It has been proposed that a high, spontaneous neurotransmission may be involved in the generation of these contraction knots. To confirm this hypothesis, we exposed mouse muscles to an anticholinesterasic agent to increase the neurotransmision in the synaptic cleft in two different conditions, in vivo and ex vivo experiments. Using intracellular recordings, a sharp increase in the spontaneous neurotransmission in the levator auris longus muscle and a lower increase in the diaphragm muscle could be seen. Likewise, electromyography recordings reveal an elevated endplate noise in gastrocnemius muscle of treated animals. These changes are associated with structural changes such as abundant neuromuscular contracted zones observed by rhodaminated α-bungarotoxin and the presence of abundant glycosaminoglycans around the contraction knots, as shown by Alcian PAS staining. In a second set of experiments, we aimed at demonstrating that the increases in the neurotransmission reproduced most of the clinical signs associated to a trigger point. We exposed rats to the anticholinesterase agent neostigmine, and 30 min afterward we observed the presence of palpable taut bands, the echocardiographic presence of contraction knots, and local twitch responses upon needle stimulation. In summary, we demonstrated that increased neurotransmission induced trigger points in both rats and mice, as evidenced by glycosaminoglycans around the contraction zones as a novel hallmark of this pathology. NEW & NOTEWORTHY In rodents, when neostigmine was injected subcutaneously, the neuromuscular neurotransmission increased, and several changes can be observed: an elevated endplate noise compared with normal endplate noise, as evidenced by electromyographyc recording; many muscular fibers with contraction knots (narrower sarcomeres and locally thickened muscle fiber) surrounded by infiltration of connective tissue like glycosaminoglycans molecules; and palpable taut bands and local twitch responses upon needle stimulation. Several of these signs are also observed in humans with muscle pain.

Thematic Areas: Zootecnia / recursos pesqueiros Sports science Sport sciences Saúde coletiva Psicología Physiology (medical) Physiology Nutrição Medicine (miscellaneous) Medicine (all) Medicina veterinaria Medicina iii Medicina ii Medicina i Interdisciplinar Geociências General medicine Farmacia Engenharias iv Educação física Ciências biológicas iii Ciências biológicas ii Ciências biológicas i Ciências ambientais Biotecnología Biodiversidade Astronomia / física

licence for use: https://creativecommons.org/licenses/by/3.0/es/

ISSN: 87507587

Author's mail: nicolauantoni.ortiz@urv.cat manuel.santafe@urv.cat sonia.monterde@urv.cat

Author identifier: 0000-0002-5462-5108 0000-0001-5580-3757

Record's date: 2023-07-31

Papper version: info:eu-repo/semantics/publishedVersion

Link to the original source: https://journals.physiology.org/doi/pdfplus/10.1152/japplphysiol.00248.2018

Licence document URL: http://repositori.urv.cat/ca/proteccio-de-dades/

Papper original source: Journal Of Applied Physiology. 126 (1): 160-169

APA: Margalef R, Sisquella M, Bosque M, Romeu C, Mayoral O, Monterde S, Priego M, Guerra-Perez R, Ortiz N, Tomàs J, Santafe M (2019). Experimental myofascial trigger point creation in rodents. Journal Of Applied Physiology, 126(1), 160-169. DOI: 10.1152/japplphysiol.00248.2018

Article's DOI: 10.1152/japplphysiol.00248.2018

Entity: Universitat Rovira i Virgili

Journal publication year: 2019

Publication Type: Journal Publications