scholarly journals Regular physical activity reduces the percentage of spinally projecting neurons that express mu-opioid receptors from the RVM

2020 ◽  
Author(s):  
KA Sluka ◽  
SJ Kolker ◽  
J Danielson ◽  
L Rasmussen
Keyword(s):  
Physical Activity ◽  
Spinal Cord ◽  
Opioid Receptors ◽  
Tryptophan Hydroxylase ◽  
Regular Physical Activity ◽  
Mu Opioid Receptors ◽  
Physically Active ◽  
Nociceptive Neurons ◽  
Mu Opioid ◽  
Running Wheels

AbstractRegular physical activity/exercise is an effective non-pharmacological treatment for individuals with chronic pain. Central inhibitory mechanisms, involving serotonin and opioids, are critical to analgesia produced by regular physical activity. The RVM sends projections to the spinal cord to inhibit or facilitate nociceptive neurons and plays a key role in exercise-induced analgesia. The goal of these studies was to examine if regular physical activity modifies RVM-spinal cord circuitry. Male and female mice received Fluoro-Gold placed on the spinal cord to identify spinally projecting neurons from the rostral ventromedial medulla (RVM) and the nucleus raphe obscuris/nucleus raphe pallidus (NRO/NRP), dermorphin-488 into caudal medulla to identify mu-opioid receptors, and were immunohistochemically stained for either phosphorylated-N-methyl-D-aspartate subunit NR1 (p-NR1) to identify excitatory neurons or tryptophan hydroxylase (TPH) to identify serotonin neurons. The percentage of dermorphin-488-positive cells that stained for p-NR1 (or TPH), and the percentage of dermorphin-488-positive cells that stained for p-NR1 (or TPH) and Fluoro-Gold was calculated.Physically active animals were provided running wheels in their cages for 8 weeks and compared to sedentary animals without running wheels. Animals with chronic muscle pain, induced by two intramuscular injections of pH 4.0, were compared to sham controls (pH 7.2). Physically active animals had less mu-opioid expressing neurons projecting to the spinal cord when compared to sedentary animals in the RVM, but not the NRO/NRP. No changes were observed for TPH. These data suggest that regular exercise alters central facilitation so that there is less descending facilitation to result in a net increase in inhibition.Summary StatementPhysically active animals has less mu-opioid expressing neurons projecting to the spinal cord in the RVM, but not the NRO/NRP, when compared to sedentary animals.

scholarly journals Activating mu-opioid receptors in the spinal cord mediates the cardioprotective effect of remote preconditioning of trauma

2017 ◽  
Vol 24 (3) ◽  
pp. 314-323 ◽  
Author(s):  
Bin Mei ◽  
Wanhong Li ◽  
Xinqi Cheng ◽  
Xuesheng Liu ◽  
Erwei Gu ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Opioid Receptors ◽  
Cardioprotective Effect ◽  
Mu Opioid Receptors ◽  
Remote Preconditioning ◽  
Mu Opioid

Pre- and postsynaptic distribution of cannabinoid and mu opioid receptors in rat spinal cord

1999 ◽  
Vol 822 (1-2) ◽  
pp. 17-25 ◽  
Author(s):  
Andrea G Hohmann ◽  
Eileen M Briley ◽  
Miles Herkenham
Keyword(s):  
Spinal Cord ◽  
Opioid Receptors ◽  
Mu Opioid Receptors ◽  
Rat Spinal Cord ◽  
Mu Opioid

Functional μ Opioid Receptors Are Reduced in the Spinal Cord Dorsal Horn of Diabetic Rats

2002 ◽  
Vol 97 (6) ◽  
pp. 1602-1608 ◽  
Author(s):  
Shao-Rui Chen ◽  
Kristi L. Sweigart ◽  
Joan M. Lakoski ◽  
Hui-Lin Pan
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Opioid Receptors ◽  
Spinal Dorsal Horn ◽  
Diabetic Rats ◽  
Spinal Cord Dorsal Horn ◽  
Mu Opioid Receptors ◽  
Mu Opioid ◽  
Spinal Dorsal ◽  
Spinal Cord Dorsal

Background The mechanisms of decreased spinal analgesic potency of morphine in neuropathic pain are not fully known. Agonist-stimulated [35S]GTPgammaS receptor autoradiography has been used to measure receptor activation of G proteins in vitro. Using this technique, we determined changes in the functional mu opioid receptors in the spinal dorsal horn in diabetic rats. Methods Rats were rendered diabetic with an intraperitoneal injection of streptozotocin. The lumbar spinal cord was obtained from age-matched normal and diabetic rats 4 weeks after streptozotocin treatment. [D-Ala2,N-MePhe4,Gly5-ol]-enkephalin (DAMGO, 10 microm)-stimulated [35S]GTPgammaS binding was performed in both tissue sections and isolated membranes. Results The DAMGO-stimulated [35S]GTPgammaS binding in the spinal dorsal horn was significantly reduced (approximately 37%) in diabetic rats compared with normal rats. However, [35S]GTPgammaS bindings in the spinal dorsal horn stimulated by other G protein-coupled receptor agonists, including [D-Pen2,D-Pen5]-enkephalin, R(-)N6-(2-phenylisopropyl)-adenosine, and WIN-55212, were not significantly altered in diabetic rats. The basal [35S]GTPgammaS binding in the spinal dorsal horn was slightly (approximately 13%) but significantly increased in diabetic rats. Western blot analysis revealed no significant difference in the expression of the alpha subunits of G(i) and G(o) proteins in the dorsal spinal cord between normal and diabetic rats. Conclusions These data suggest that the functional mu opioid receptors in the spinal cord dorsal horn of diabetic rats are reduced. The impaired functional mu opioid receptors in the spinal cord may constitute one of the mechanisms underlying the reduced spinal analgesic effect of mu opioids in diabetic neuropathic pain.

Correlation Between Physical Activity Level and Functional Status of Subjects with High Spinal Cord Injury

2021 ◽  
Author(s):  
Ewa Szeliga ◽  
Renata Borys ◽  
Agnieszka Brzozowska-Magoń ◽  
Andżelina Wolan-Nieroda ◽  
Grzegorz Magoń ◽  
...  
Keyword(s):  
Physical Activity ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Functional Status ◽  
Cervical Spinal Cord ◽  
Regular Physical Activity ◽  
Physically Active ◽  
Wheelchair Rugby ◽  
Cord Injury ◽  
Inactive Group

Abstract Background. Spinal cord injuries are one of the main causes of disability in Poland and in the world. Quadriparesis, limitations in activities of daily living, lack of full autonomy and psycho-social problems are consequences of cervical spinal cord injury. Due to the consequences, especially motor paralysis and sedentary lifestyle resulting from spinal injuries, much attention is drawn to physical activity in subjects with this type of injuries. Objective. The aim of the study is to assess the effect of regular physical activity on functional fitness and independent existence of subjects after high spinal cord injury.Methods. 80 subjects with transverse injury of cervical spinal cord were enrolled in the study. The study group included men aged 20-50, in which group 40 (50%) of the subjects were qualified to the physically active group – subjects doing wheelchair sport, and 40 (50%) of the subjects were qualified to the physically inactive group – subjects taking no physical activity. The physically active men were qualified on the basis of their participation in organised activities - wheelchair rugby. Minimum participation was 90 minutes a day twice a week. Subjects from the physically inactive group had a passive lifestyle and participated in no sports activities. Results. Highly significant differences were observed during the study between the physically active and inactive men with regard to the functionality status. The study subjects taking regular physical exercise had better results in all assessed activities. The biggest differences were observed in the field of toilet and dressing up. Conclusions. The study confirmed that regular physical activity is correlated with better fitness. The study also showed that the subjects playing wheelchair rugby are more independent, which results in their better functional status in everyday life.

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