scholarly journals Sprouting of substance P-expressing primary afferent central terminals and spinal micturition reflex NK1 receptor dependence after spinal cord injury

2008 ◽  
Vol 295 (6) ◽  
pp. R2084-R2096 ◽  
Author(s):  
Xiaoyang Zhang ◽  
Kristy L. Douglas ◽  
Huixia Jin ◽  
Bassem M. Eldaif ◽  
Rashid Nassar ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Substance P ◽  
Nk1 Receptor ◽  
External Urethral Sphincter ◽  
Primary Afferent ◽  
Micturition Reflex ◽  
Cord Injury ◽  
High Doses ◽  
Intact Rats

The primary afferent neurotransmitter triggering the spinal micturition reflex after complete spinal cord injury (SCI) in the rat is unknown. Substance P detected immunohistochemically in the sacral parasympathetic nucleus was significantly higher in 12 SCI rats than in 12 spinally intact rats ( P = 0.008), suggesting substance P as a plausible candidate for the primary afferent neurotransmitter. The effects of the tachykinin NK1 receptor antagonist L-733060 on the spinal micturition reflex were then determined by performing conscious cystometry in an additional 14 intact rats and 14 SCI rats with L-733060 (0.1–100 μg) administered intrathecally at L6-S1. L-733060 was without effect in intact rats, but blocked the spinal micturition reflex in 10 of 14 SCI rats and increased the intermicturition interval in 2 of 4 others at doses ranging from 10 to 100 μg. Both phasic and nonphasic voiding contractions, differentiated according to the presence of phasic external urethral sphincter (EUS) activity, were present in most SCI rats. Both types of contractions were blocked by high doses of L-733060. Interestingly, there was a relative decline in phasic voiding contractions at high doses as well as a decline in contraction amplitude in nonphasic voiding contractions. In other respects, cystometric variables were largely unaffected in either spinally intact or SCI rats. L-733060 did not affect tonic EUS activity at any dose except when the spinal micturition reflex was blocked and tonic activity was consequently lost. These experiments show that tachykinin action at spinal NK1 receptors plays a major role in the spinal micturition reflex in SCI rats.

scholarly journals Changes in substance P and NK1 receptor immunohistochemistry following human spinal cord injury

Spinal Cord ◽  
2013 ◽  
Vol 52 (1) ◽  
pp. 17-23 ◽  
Author(s):  
A V Leonard ◽  
J Manavis ◽  
P C Blumbergs ◽  
R Vink
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Substance P ◽  
Nk1 Receptor ◽  
Human Spinal Cord ◽  
Cord Injury

scholarly journals THE ENTROPY OF DISCRETE-TIME FRACTIONAL GAUSSIAN NOISE AND ITS APPLICATION TO THE ELECTROMYOGRAM OF EXTERNAL URETHRAL SPHINCTER SIGNALS

2001 ◽  
Vol 13 (06) ◽  
pp. 256-261
Author(s):  
YEN-CHING CHANG ◽  
SHYANG CHANG
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Discrete Time ◽  
Gaussian Noise ◽  
Hurst Parameter ◽  
Urethral Sphincter ◽  
Fractional Gaussian Noise ◽  
External Urethral Sphincter ◽  
Cord Injury ◽  
Intact Rats

In this work, we will study the Hurst parameter embedded in the discrete-time fraction Gaussian noise (DFGN) and derive the entropy with this parameter. It will be applied to the electromyogram (EMG) of external urethral sphincter (EUS). These signals come from intact rats and the injured ones from spinal cord injury (SCI). Analysis indicates that we can discriminate between intact and SCI rats from this information.

scholarly journals Delivery of the 5-HT2A Receptor Agonist, DOI, Enhances Activity of the Sphincter Muscle during the Micturition Reflex in Rats after Spinal Cord Injury

Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 68
Author(s):  
Jaclyn H. DeFinis ◽  
Jeremy Weinberger ◽  
Shaoping Hou
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Receptor Agonist ◽  
Subcutaneous Administration ◽  
Receptor Subtype ◽  
Synergistic Activity ◽  
Sphincter Muscle ◽  
External Urethral Sphincter ◽  
Micturition Reflex ◽  
Cord Injury

Traumatic spinal cord injury (SCI) interrupts spinobulbospinal micturition reflex pathways and results in urinary dysfunction. Over time, an involuntary bladder reflex is established due to the reorganization of spinal circuitry. Previous studies show that manipulation of serotonin 2A (5-HT2A) receptors affects recovered bladder function, but it remains unclear if this receptor regulates the activity of the external urethral sphincter (EUS) following SCI. To elucidate how central and peripheral serotonergic machinery acts on the lower urinary tract (LUT) system, we employed bladder cystometry and EUS electromyography recordings combined with intravenous or intrathecal pharmacological interventions of 5-HT2A receptors in female SCI rats. Three to four weeks after a T10 spinal transection, systemic and central blockage of 5-HT2A receptors with MDL only slightly influenced the micturition reflex. However, delivery of the 5-HT2A receptor agonist, DOI, increased EUS tonic activity and elicited bursting during voiding. Additionally, subcutaneous administration of DOI verified the enhancement of continence and voiding capability during spontaneous micturition in metabolic cage assays. Although spinal 5HT2A receptors may not be actively involved in the recovered micturition reflex, stimulating this receptor subtype enhances EUS function and the synergistic activity between the detrusor and sphincter to improve the micturition reflex in rats with SCI.

Spatiotemporal CCR1, CCL3(MIP-1α), CXCR4, CXCL12(SDF-1α) expression patterns in a rat spinal cord injury model of posttraumatic neuropathic pain

2011 ◽  
Vol 14 (5) ◽  
pp. 583-597 ◽  
Author(s):  
Friederike Knerlich-Lukoschus ◽  
Beata von der Ropp-Brenner ◽  
Ralph Lucius ◽  
Hubertus Maximilian Mehdorn ◽  
Janka Held-Feindt
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Neuropathic Pain ◽  
Substance P ◽  
Time Course ◽  
Behavioral Testing ◽  
Dorsal Horns ◽  
Cord Injury ◽  
Dorsal Columns ◽  
Spinal Cord Contusion

Object Central neuropathic pain is a frequent challenging complication after spinal cord injury (SCI), and specific therapeutic approaches remain elusive. The purpose of the present investigations was to identify potential key mediators of these pain syndromes by analyzing detailed expression profiles of important chemokines in an experimental SCI paradigm of posttraumatic neuropathic pain in rats. Methods Expression of CCR1, CCL3(MIP-1α), CXCR4, and CXCL12(SDF-1α) was investigated in parallel with behavioral testing for mechanical and thermal nociceptive thresholds after standardized SCI; 100-kdyn (moderate injury) and 200-kdyn (severe injury) force-defined thoracic spinal cord contusion lesions were applied via an Infinite Horizon Impactor at the T-9 level. Sham controls received laminectomies. Hindlimb locomotor function as well as mechanical and thermal sensitivities were monitored weekly by standardized behavioral testing after SCI. Chemokine expression was analyzed by real-time reverse transcriptase polymerase chain reaction in the early (7 days postoperatively) and late (42 days postoperatively) time courses after SCI, and immunohistochemical analysis (anatomical and quantitative) was performed 2, 7, 14, and 42 days after lesioning. Double staining with cellular markers and pain-related peptides (substance P and CGRP) or receptors (TRPV-1, TRPV-2, VRL-1, and TLR-4) was performed. Based on data obtained from behavioral testing, quantified immunohistochemical chemokine expressions in individual animals were correlated with the respective mechanical and thermal sensitivity thresholds 6 weeks after SCI. Results After 200-kdyn lesions, the animals exhibited prolonged reduction in their nociceptive thresholds, while 100-kdyn groups showed pain-related behaviors only in the early time course after SCI. Investigated chemokines were widely induced after SCI, involving cervical, thoracic, and lumbar spinal cord levels far beyond the lesion core. CCR1 and CCL3 were induced significantly in the dorsal horns 2 days after lesioning and remained at high levels after SCI with significantly higher intensities after 200-kdyn than 100-kdyn contusions. CXCR4 and CXCL12 levels continuously increased from 2 to 42 days after moderate and severe lesions. Additionally, chemokines were induced significantly in dorsal columns, with highest density levels 42 days after 200-kdyn lesions. In dorsal horns, CCR1 was coexpressed with TRPV-1 while CXCR4 and CXCL12 were partially coexpressed with substance P and CGRP. In dorsal columns, CCL3/CCR1 colabeled with GFAP, TRPV-2, TRPV-1, TLR-4; CXCR4/CXCL12 coexpressed with GFAP, CD68/ED1, and TLR4. Chemokine immunoreactivity density levels, especially CCL3 and its receptor, correlated in part significantly with nociceptive thresholds. Conclusions The authors report lesion grade–dependent upregulation of different chemokines/chemokine receptors after spinal cord contusion lesions in pain-processing spinal cord regions in a clinically relevant model of traumatic SCI in rats. Prolonged chemokine induction further correlated with below-level pain development in the delayed time course after severe SCI and was coexpressed with pain-associated peptides and receptors, suggesting that chemokines play a crucial role in chronic central pain mechanisms after SCI.

scholarly journals α1D-Adrenoceptor blockade increases voiding efficiency by improving external urethral sphincter activity in rats with spinal cord injury

2016 ◽  
Vol 311 (5) ◽  
pp. R971-R978 ◽  
Author(s):  
Hirokazu Ishida ◽  
Hiroki Yamauchi ◽  
Hideaki Ito ◽  
Hironobu Akino ◽  
Osamu Yokoyama
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Lower Urinary Tract Dysfunction ◽  
Urethral Sphincter ◽  
Sprague Dawley ◽  
External Urethral Sphincter ◽  
Detrusor Sphincter Dyssynergia ◽  
Sphincter Electromyography ◽  
Sprague Dawley Rats ◽  
Cord Injury

Ideal therapy for lower urinary tract dysfunction in patients with spinal cord injury (SCI) should decrease detrusor overactivity, thereby promoting urine storage at low intravesical pressure and promoting efficient voiding at low pressure by decreasing detrusor-sphincter dyssynergia. Here we investigated blockade of various α-adrenoceptors to determine the subtype that was principally responsible for improving the voiding dysfunction. The effects of the intravenous α-blocker naftopidil, the α-blocker BMY 7378, and the α-blocker silodosin were evaluated using cystometrography and external urethral sphincter-electromyography (EMG) in decerebrated, unanesthetized female Sprague-Dawley rats with chronic SCI following transection at Th8. Parameters measured included the voided volume, residual volume, voiding efficiency, and burst and silent periods on EMG. Compared with values in decerebrated non-SCI rats, EMG of decerebrated SCI rats revealed more prominent tonic activity, significantly shorter periods of bursting activity, and a reduced ratio of the silent to active period during bursting. Compared with the value before drug administration (control), the voiding efficiency was significantly increased by naftopidil (1 and 3 mg/kg) (<0.05 each), and the burst (<0.01 and <0.05, respectively) and silent periods (<0.01 each) on EMG were significantly lengthened. BMY 7378 (1 mg/kg) significantly increased voiding efficiency and lengthened the burst periods (<0.05 each). Silodosin did not affect any parameters. These results suggest that α-blockade reduces the urethral resistance associated with detrusor-sphincter dyssynergia, thus improving voiding efficiency in SCI rats.

Activation of the external urethral sphincter central pattern generator by a 5-HT1A receptor agonist in rats with chronic spinal cord injury

2007 ◽  
Vol 292 (4) ◽  
pp. R1699-R1706 ◽  
Author(s):  
Paul C. Dolber ◽  
Baojun Gu ◽  
Xiaoyang Zhang ◽  
Matthew O. Fraser ◽  
Karl B. Thor ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Receptor Agonist ◽  
Bladder Capacity ◽  
Female Rats ◽  
Residual Volume ◽  
Urethral Sphincter ◽  
External Urethral Sphincter ◽  
Chronic Spinal Cord Injury ◽  
Cord Injury

We recently demonstrated that treatment with the 5-HT1A/7 receptor agonist [(R)-(+)-8-hydroxy-2-di-n-propylamino]tetralin (8-OH-DPAT) increases bladder capacity in chloralose-anesthetized female cats with chronic spinal cord injury. In the current study, we investigated the effects of 8-OH-DPAT on bladder capacity and external urethral sphincter (EUS) activity in urethane-anesthetized female rats (initial body mass 175–200 g) with chronic spinal cord injury (transsection at T10). Cystometric study took place 8–12 wk posttranssection. Intravesical pressure was monitored in urethane-anesthetized rats with a transvesical catheter, and EUS activity was assessed electromyographically. Spinal cord injury disrupts phasic activity of the EUS, resulting in decreased voiding efficiency and increased residual volume. 8-OH-DPAT induced a dose-dependent decrease in bladder capacity (the opposite of its effect in chronic spinal cord-injured cats) with an increase in micturition volume and decrease in residual volume resulting from improvement in voiding efficiency. The unexpected improvement in voiding efficiency can be explained by the 8-OH-DPAT-induced emergence of phasic EUS relaxation. Phasic EUS relaxation was also altered by 8-OH-DPAT in spinally intact rats, whereas the 5-HT1A receptor antagonist N-tert-butyl-3-[4-(2-methoxyphenyl)-piperazin-1-yl]-2-phenylpropanamide (WAY-100635), on its own, was without effect. It remains to be determined when phasic relaxation is restored after spinal cord injury, and indeed whether it is ever truly lost or is only temporarily separated from excitatory input.

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