Dataset Information

Deep Tissue Incision Enhances Spinal Dorsal Horn Neuron Activity During Static Isometric Muscle Contraction in Rats.

ABSTRACT: Translational correlates to pain with activities after deep tissue injury have been rarely studied. We hypothesized that deep tissue incision causes greater activation of nociception-transmitting neurons evoked by muscle contraction. In vivo neuronal activity was recorded in 203 dorsal horn neurons (DHNs) from 97 rats after sham, skin-only, or skin?+?deep muscle incision. We evaluated DHN responses to static, isometric muscle contractions induced by direct electrical stimulation of the muscle. The effect of pancuronium on DHN response to contractions was also examined. Approximately 50% of DHNs with receptive fields in the hindpaw were excited during muscle contraction. One-second .5- and 1.0-g muscle contractions produced greater DHN activity after skin?+?deep muscle incision (median [interquartile range], 32 [5-39] impulses, P?=?.021; and 36 [26-46] impulses, P?=?.006, respectively) than after sham (6 [0-21] and 15 [8-32] impulses, respectively). Neuromuscular blockade with pancuronium inhibited the muscle contractions and DHN activation during electrical stimulation, demonstrating contraction-induced activation. The greater response of spinal DHNs to static muscle contraction after skin?+?deep muscle incision may model and inform mechanisms of dynamic pain after surgery. PERSPECTIVE: Completion of various activities is an important milestone for recovery and hospital discharge after surgery. Skin?+?deep muscle incision caused greater activation of nociception-transmitting DHNs evoked by muscle contraction compared with skin-only incision. This result suggests an important contribution of deep muscle injury to activity-evoked hyperalgesia after surgery.

SUBMITTER: Gu H

PROVIDER: S-EPMC6382557 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

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Deep Tissue Incision Enhances Spinal Dorsal Horn Neuron Activity During Static Isometric Muscle Contraction in Rats.

Gu He H Sugiyama Daisuke D Kang Sinyoung S Brennan Timothy J TJ

The journal of pain 20181006 3

Translational correlates to pain with activities after deep tissue injury have been rarely studied. We hypothesized that deep tissue incision causes greater activation of nociception-transmitting neurons evoked by muscle contraction. In vivo neuronal activity was recorded in 203 dorsal horn neurons (DHNs) from 97 rats after sham, skin-only, or skin + deep muscle incision. We evaluated DHN responses to static, isometric muscle contractions induced by direct electrical stimulation of the muscle. T ...[more]

PMID: 30296612

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Project description:Lysophosphatidyl-choline (LPC), a member of the phospholipid family, is an emerging player in pain. It is known to modulate different pain-related ion channels, including Acid-Sensing Ion Channel 3 (ASIC3), a cationic channel mainly expressed in peripheral sensory neurons. LPC potentiates ASIC3 current evoked by mild acidifications, but can also activate the channel at physiological pH. Very recently, LPC has been associated to chronic pain in patients suffering from fibromyalgia or osteoarthritis. Accordingly, repetitive injections of LPC within mouse muscle or joint generate both persistent pain-like and anxiety-like behaviors in an ASIC3-dependent manner. LPC has also been reported to generate acute pain behaviors when injected intraplantarly in rodents. Here, we explore the mechanism of action of a single cutaneous injection of LPC by studying its effects on spinal dorsal horn neurons. We combine pharmacological, molecular and functional approaches including in vitro patch clamp recordings and in vivo recordings of spinal neuronal activity. We show that a single cutaneous injection of LPC exclusively affects the nociceptive pathway, inducing an ASIC3-dependent sensitization of nociceptive fibers that leads to hyperexcitabilities of both high threshold (HT) and wide dynamic range (WDR) spinal neurons. ASIC3 is involved in LPC-induced increase of WDR neuron's windup as well as in WDR and HT neuron's mechanical hypersensitivity, and it participates, together with TRPV1, to HT neuron's thermal hypersensitivity. The nociceptive input induced by a single LPC cutaneous rather induces short-term sensitization, contrary to previously described injections in muscle and joint. If the effects of peripheral LPC on nociceptive pathways appear to mainly depend on peripheral ASIC3 channels, their consequences on pain may also depend on the tissue injected. Our findings contribute to a better understanding of the nociceptive signaling pathway activated by peripheral LPC via ASIC3 channels, which is an important step regarding the ASIC3-dependent roles of this phospholipid in acute and chronic pain conditions.

Project description:The electroacupuncture-induced analgesic effect has been used widely to alleviate diverse pains. However, significant individual variations in analgesic effect of EA for both experiments and clinics were reported. According to the sensitivity of the analgesic response to EA stimulation, the subjects could be categorized into high responders (HR) and low responders (LR). However, the molecular mechanism of individual variability in the analgesic response to acupuncture stimulation is still uncertain. This study aims to investigate the potential gene expression in spinal dorsal horn induced by 2Hz/100Hz electroacupuncture in HR and LR rats. Rats were given 2Hz or 100Hz electroacupuncture for 30 min and using cDNA microarrays to compare different gene expression in dorsal horn. Transcriptome profiling analysis found that some co-regulated genes related with electroacupuncture or 2Hz or 100Hz freqencies. These co-regulated genes were plasticity-related by GO analysis. We also found some special regulated genes in HR vs. LR in 2Hz/100Hz electroacupuncture stimulation. These results suggested that neurotransmitter system and cytokine different between HR with LR in 2Hz electroacupuncture. But in 100Hz electroacupunture, there were many different regulated genes related with ribosome between HR with LR, which needs more studies to research the function and may play an important role in HR vs. LR by 100Hz electroacupuncture. Keywords: Transcriptome analysis Rats were exposed to different frequencies (2Hz or 100Hz) electroacupuncture stimlation for 30 min and nociceptive testing and returned to home cages for 1 hours before sacrificed. According to the sensitivity of the analgesic response to 2Hz or 100Hz EA stimulation, the rats divided into four groups: 2Hz-HR group, 2Hz-LR group, 100Hz-HR group and 100Hz-LR group. Subsequently analyzed their dorsal horn transcript profile using cDNA microarrays, the rats were without receiving electroacupuncture as control. The tissue of dorsal horn (DH) of the fifth and sixth lumbar (L5 and L6) of four or five rats were selected for transcript analysis in each group. The five control rats were mixed and labeled with cy5, each rat of experiment groups was labeled with cy3.

Dataset Information

Deep Tissue Incision Enhances Spinal Dorsal Horn Neuron Activity During Static Isometric Muscle Contraction in Rats.

Publications

Deep Tissue Incision Enhances Spinal Dorsal Horn Neuron Activity During Static Isometric Muscle Contraction in Rats.

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