scholarly journals Patch Clamp Recordings on Intact Dorsal Root Ganglia from Adult Rats

10.3791/54287 ◽  
2016 ◽  
Author(s):  
Kerui Gong ◽  
Peter T. Ohara ◽  
Luc Jasmin
Keyword(s):  
Patch Clamp ◽  
Dorsal Root Ganglia ◽  
Dorsal Root ◽  
Adult Rats

scholarly journals A213 A NOVEL PH-SENSITIVE OPIOID ANALGESIC THAT IS SELECTIVELY ACTIVATED IN ACIDIC INFLAMMATORY ENVIRONMENTS

2020 ◽  
Vol 3 (Supplement_1) ◽  
pp. 85-87
Author(s):  
Y Yu ◽  
N N Jiménez-Vargas ◽  
C D Lopez Lopez ◽  
J O Jaramillo Polanco ◽  
N W Bunnett ◽  
...  
Keyword(s):  
Patch Clamp ◽  
Dorsal Root Ganglia ◽  
Dorsal Root ◽  
Opioid Analgesic ◽  
Ph Sensitive ◽  
Afferent Nerve ◽  
Acid Dissociation ◽  
Acid Dissociation Constant ◽  
Acidic Ph ◽  
Nerve Recordings

Abstract Background Opioids drugs are effective analgesics for inflammatory disorders such as inflammatory bowel disease (IBD) but their effects at non-inflammed sites can cause serious morbidity and even death. Exploiting the knowledge that tissue pH in inflamed tissues is acidic (e.g. 6.5–7.0), a novel opioid analgesic, ±)-N-(3-fluoro-1-phenethylpiperidine-4-yl)-N-phenylpropionamide (NFEPP), with a low acid dissociation constant, was developed that selectively activates peripheral µ-opioid receptor (MOPr) at acidic pH. Thus, pH-sensitive binding of NFEPP could selectively inhibit nociceptive nerves in the inflamed colon and have no effect on non-inflamed tissues outside the GI tract. Aims Evaluate whether NFEPP causes inhibition of colonic nociceptors at acidic pH’s, which mimic the inflamed colon. Methods To evaluate pH sensitive property of NFEPP to activate MOPr, dorsal root ganglia (DRG) neurons from C57BL/6 mice were exposed to the MOPr agonists NFEPP (300nM, 15 min) or DAMGO (100nM, 15 min) or vehicle at pH 6.5 or 6.8 or 7.4. Neuronal excitability was measured by recording the rheobase (minimum current to fire an action potential) using patch clamp recordings of isolated dorsal root ganglia neurons. In parallel ex vivo studies of mouse colon, extracellular recordings were obtained from afferent nerves innervating the distal colon. Afferent responses to probing with von Frey hair (1 gm) were examined before and after exposure to NFEPP (300nM, 5 min superfusion) at pH 6.5 and 7.4 respectively. Oneway ANOVA and post hoc Dunnett and Bonferroni tests were used to analyze the data. Results In patch clamp studies, NFEPP caused a decrease in DRG excitability at pH 6.5 and 6.8 (increased rheobase 21.3%, p<0.05 and 28.9%, p<0.05 respectively compared to vehicle) but had no effect at physiological pH 7.4. DAMGO, a MOPr agonist, caused inhibition of nociceptor excitability at pH 7.4 (increased rheobase 25.2%, p<0.05 compared to vehicle) as shown in previous experiments, but had no effect at pH 6.5 and 6.8. Vehicle had no effect at the different pH’s. In colonic afferent nerve recordings, NFEPP significantly attenuated afferent response (28.9% P<0.01) to probing at pH 6.5 and this effect was reversed after a 15 min washout. At pH 7.4 NFEPP had no effect on afferent nerve firing. Conclusions NFEPP activated MOPr at acidic pH causing inhibition of colonic nociceptors. This pH-selective agonist provides a new strategy to relieve pain at the site of inflammation while being devoid of any of unwanted activity in non-inflamed organs. Funding Agencies CCC

scholarly journals RNAseq dataset describing transcriptional changes in cervical sensory ganglia after bilateral pyramidotomy and forelimb intramuscular gene therapy with AAV1 encoding human neurotrophin-3

2018 ◽  
Author(s):  
Claudia Kathe ◽  
Lawrence D F Moon
Keyword(s):  
Gene Expression ◽  
Dorsal Root Ganglia ◽  
Small Rnas ◽  
Dorsal Root ◽  
Viral Vector ◽  
Cervical Spinal Cord ◽  
Neurological Injury ◽  
Adult Rats ◽  
Abnormal Movements ◽  
Neurotrophin 3

AbstractUnilateral or bilateral corticospinal tract injury in the pyramids of adult rats causes changes in proprioceptive axon terminal arborization in the cervical spinal cord accompanied by hyperreflexia and abnormal movements including spasms [1, 2]. Treatment of affected forelimb muscles with an Adeno-Associated Viral Vector (AAV) encoding human neurotrophin-3 (NT3) normalizes many of these anatomical, neurophysiological and behavioural changes [1]. Interestingly, in several studies, neurotrophin-3 protein accumulates in cervical dorsal root ganglia (DRG) on the side ipsilateral to AAV injection [1, 3]. We hypothesize that neurotrophin-3 induces these changes (in proprioceptive axon wiring, proprioceptive reflex neurophysiology and sensorimotor behaviors involving proprioception) by modifying gene expression in affected cervical dorsal root ganglia (DRG). As a first step in testing this hypothesis, we analyzed the transcriptomes of cervical DRGs obtained during a previous study from naïve rats and from rats after bilateral pyramidotomy (bPYX) with unilateral intramuscular injections of either AAV1-CMV-NT3 or AAV1-CMV-EGFP made 24h after injury [1]. Ten weeks after surgery, Poly(A) RNAs and small RNAs from C6 to C8 DRGs on the treated side were sequenced. We detected mRNAs or small RNAs that were significantly regulated under three conditions (bPYX+GFP vs naïve; bPYX+NT3 versus naïve; bPYX+NT3 vs bPYX+GFP). We identified mRNAs and small RNAs whose expression level was altered after pyramidotomy and normalized by neurotrophin-3 treatment. A bioinformatic analysis enabled us to identify genes that are likely to be expressed in proprioceptors after injury and which were regulated by neurotrophin-3 in the direction expected from other datasets involving knockout or overexpression of neurotrophin-3. This dataset will help us and others identify genes in sensory neurons whose expression levels are regulated by neurotrophin-3 treatment. This may help identify novel therapeutic targets to improve sensation and movement after neurological injury. Data has been deposited in the Gene Expression Omnibus (GSE82197).

scholarly journals Generation of New Neurons in Dorsal Root Ganglia in Adult Rats after Peripheral Nerve Crush Injury

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Luisa Muratori ◽  
Giulia Ronchi ◽  
Stefania Raimondo ◽  
Stefano Geuna ◽  
Maria Giuseppina Giacobini-Robecchi ◽  
...  
Keyword(s):  
Sensory Neurons ◽  
Dorsal Root Ganglia ◽  
Dorsal Root ◽  
Morphological Changes ◽  
Dorsal Root Ganglion Neurons ◽  
Cell Phenotype ◽  
Adult Rats ◽  
Nerve Crush ◽  
Satellite Glial Cells ◽  
Ganglion Neurons

The evidence of neurons generatedex novoin sensory ganglia of adult animals is still debated. In the present study, we investigated, using high resolution light microscopy and stereological analysis, the changes in the number of neurons in dorsal root ganglia after 30 days from a crush lesion of the rat brachial plexus terminal branches. Results showed, as expected, a relevant hypertrophy of dorsal root ganglion neurons. In addition, we reported, for the first time in the literature, that neuronal hypertrophy was accompanied by massive neuronal hyperplasia leading to a 42% increase of the number of primary sensory neurons. Moreover, ultrastructural analyses on sensory neurons showed that there was not a relevant neuronal loss as a consequence of the nerve injury. The evidence of BrdU-immunopositive neurons and neural progenitors labeled with Ki67, nanog, nestin, and sox-2 confirmed the stereological evidence of posttraumatic neurogenesis in dorsal root ganglia. Analysis of morphological changes following axonal damage in addition to immunofluorescence characterization of cell phenotype suggested that the neuronal precursors which give rise to the newly generated neurons could be represented by satellite glial cells that actively proliferate after the lesion and are able to differentiate toward the neuronal lineage.

Expression of peripherin in solid transplants of foetal spinal cord and dorsal root ganglia grafted to the injured cervical spinal cord of adult rats

1994 ◽  
Vol 170 (1) ◽  
pp. 59-62 ◽  
Author(s):  
F. Rhrich-Haddout ◽  
J.-C. Horvat ◽  
C. Baillet-Derbin ◽  
K. Djabali ◽  
M.M. Portier
Keyword(s):  
Spinal Cord ◽  
Dorsal Root Ganglia ◽  
Dorsal Root ◽  
Cervical Spinal Cord ◽  
Adult Rats
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