Chronic Increases in Daily Neuromuscular Activity Promote Changes in Gene Expression in Small and Large Dorsal Root Ganglion Neurons in Rat. (15th September 2018)

• Record Type: Journal Article
• Authors: Paddock, Natasha; Sheppard, Patricia; Gardiner, Phillip
• Is Part Of: Neuroscience. Volume 388(2018)
• Page Start: 171
• Page End: 180
• Publication Date: 2018-09-15
• Subjects: BDNF brain-derived neurotrophic factor -- cDNA complementary deoxyribonucleic acid -- CGRP calcitonin gene-related peptide -- CNR cannabinoid receptor -- CREB cAMP response element-binding protein -- DNA deoxyribonucleic acid -- DRG dorsal root ganglia -- GAP growth-associated protein -- Kv voltage-gated potassium channel -- L lumbar -- LCM laser capture microdissection -- LTP long-term potentiation -- MAPK mitogen-activated protein kinases -- mRNA messenger ribonucleic acid -- MSR monosynaptic reflex -- Nav voltage-gated sodium channel -- NGF nerve growth factor -- NT neurotrophin -- NTM neurotransmitter -- OPRD δ-opioid receptor (DOR -- OPRM opioid receptor mu subunit (MOR) -- PA physical activity -- PAF primary afferent terminal -- PI3K phosphoinositide 3-kinase -- PKC protein kinase C -- PLC phospholipase C -- PNS peripheral nervous system -- PSI presynaptic inhibition -- RIN RNA integrity numbe -- RNA ribonucleic acid -- RQ relative quantification -- (RT)/qPCR quantitative real-time polymerase chain reaction -- SDHA succinate dehydrogenase complex subunit A -- STX syntaxin -- SYN synapsin -- Trk tyrosine-related kinase receptor -- TRPV transient receptor potential vanilloid -- 5HT serotonin; dorsal root ganglia -- exercise -- gene expression -- sensory neurons -- laser capture microdissection; Neurochemistry -- Periodicals; Neurophysiology -- Periodicals; Neurology -- Periodicals; Neurochimie -- Périodiques; Neurophysiologie -- Périodiques; Neurochemistry; Neurophysiology; Electronic journals; Periodicals; Electronic journals; 612.8
• DOI: 10.1016/j.neuroscience.2018.07.016
• Languages: English
• ISSNs: 0306-4522

Abstract

Highlights: Rats were subjected to daily exercise for 16–18 weeks. Large and small rat DRG neurons were separated using laser capture microdissection. Daily exercise altered gene expression in rat lumbar DRG neurons. Small and large DRG neurons often showed different responses to exercise. Daily treadmill and voluntary wheel activity elicited different responses. Abstract: The purpose of this study was to determine the response, in rat, to chronic physical activity in small and large DRG neurons. Rats were cage-confined or underwent 16–18 weeks of daily increased activity, via 2 h of treadmill running per day or free access to voluntary exercise wheels, following which small (≤30 µm) and large (≥40 µm) diameter DRG neurons were harvested by laser capture microdissection from flash-frozen lumbar DRGs. Relative mRNA levels were determined using real-time polymerase chain reaction. Following chronic treadmill and voluntary wheel exercise, gene expression responses in neurons mostly differed between exercise types. Changes in both small and large DRG neurons included increases in opioid receptor mu subunit (MOR), NGF and GAP43, and decreases in 5HT1A, TrkA, TrkB, and delta-type opioid receptor (DOR) mRNAs. In small DRG neurons, treadmill exercise increased the expression of mRNA for 5HT1D and decreased expression for 5HT1F receptors. In large DRG neurons, voluntary wheel exercise decreased the expression for 5HT1D receptors, whereas both treadmill and voluntary wheel exercise decreased the expression of mRNA for TrkC receptors. DRG neurons show slightly more changes in gene expression after voluntary exercise compared to the treadmill exercise group. Small and large lumbar sensory neurons are responsive to chronically increased neuromuscular activity by changing the expression of genes, the products of which could potentially change the sensory processing of nociceptors and proprioceptors, which could in turn alter functions such as pain transmission and locomotor coordination.