Evidence for Alterations of Synaptic Inputs to Sacral Spinal Reflex Circuits after Spinal Cord Transection in the Cat

Ms, Beattie; Mg, Leedy; Jc, Bresnahan

doi:10.1006/exnr.1993.1138

Cited by 39 publications

(20 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Efferent innervation is likely to undergo changes as well. After thoracic transection, there is dendritic degeneration and decreased somal sze of sympathetic preganglionic neurons innervating the bladder (Krassioukov and Weaver, 1995), and synaptic alterations of sacral parasympathetic preganglionic and Onuf's nucleus neurons innervating the urethra (Beattie et al, 1993).…”

Section: Discussionmentioning

confidence: 99%

Assessment of Lower Urinary Tract Functional Deficit in Rats With Contusive Spinal Cord Injury

Pikov

Gillis²,

Jasmin³

et al. 1998

Journal of Neurotrauma

View full text Add to dashboard Cite

Traumatic spinal cord injury (SCI) produces lower urinary tract (LUT) dysfunction that has been studied in surgical transection models. Our aim was to assess LUT functional deficit in a clinically relevant model of incomplete SCI to investigate how partial preservation of supraspinal connections might affect LUT dysfunction. Standardized weight-drop contusion (10 g x 2.5 cm) or complete transection, was produced at T8 in female Sprague-Dawley rats. Behavioral tests were used to assess hind limb sensorimotor function at Day 1 after surgery and weekly thereafter. The urometric experiments were conducted on groups (n = 7) of uninjured rats and on injured rats during Weeks 1 and 2 after SCI (before and after spontaneous voiding was established) as well as Week 2 after a complete transection (n = 3). Under anesthesia, the bladder was continuously perfused with saline. Changes in bladder pressure and external urethral sphincter (EUS) electrical activity were monitored. The bladder was then dissected and weighed and both the bladder and spinal cord were fixed for pathoanatomical analyses. Our results indicate that several aspects of LUT dysfunction after contusive SCI were similar to transection, e.g., reduction of voiding efficiency (approximately 5% of normal value), decrease in inter-contraction interval (47%), increase in bladder capacity (8-fold), and weight (4.6-fold). One aspect appeared different from transection--partial recovery from acute bladder/sphincter dyssynergia. Because the coordination of bladder and EUS function is mediated by brainstem pathways, partial recovery of synergy after SCI was likely due to sparing of some relevant bulbospinal projections as was confirmed by retrograde transneuronal viral tracing.

show abstract

Section: Discussionmentioning

confidence: 99%

Assessment of Lower Urinary Tract Functional Deficit in Rats With Contusive Spinal Cord Injury

Pikov

Gillis²,

Jasmin³

et al. 1998

Journal of Neurotrauma

View full text Add to dashboard Cite

show abstract

“…The expulsion of the semen requires the coordinated and rhythmic contraction of the striated perineal muscles, the bulbocavernosus muscle, the ischiocavernosus muscle, and the external urethral sphincter (Johnson, 1988;Holmes et al, 1991;Schmidt & Schmidt, 1993;Yang & Bradley, 1999). In humans, the responsible centre for this second phase is the Onuf's nucleus located in the ventral horn of the spinal cord at the S2-level (Schroder, 1985;Beattie et al, 1993).…”

Section: Ejaculationmentioning

confidence: 98%

Erectile function and male reproduction in men with spinal cord injury: a review

et al. 2010

View full text Add to dashboard Cite

Spinal cord injury (SCI) in men results in defects in erectile function, ejaculatory process and male reproductive potential. There are alterations in the capacity of men with SCI to achieve reflexogenic, psychogenic and nocturnal erections. The sexual function in different stages after SCI and the types of erections depend mainly on the completeness of the injury and the level of neurological damage. Furthermore, most of the SCI men demonstrate defects concerning the entrance of semen into the posterior urethra and the expulsion of the semen through the penile urethra and the urethral orifice. In addition, SCI men develop defects in the secretory function of the Leydig cells, Sertoli cells and the male accessory genital glands. The overall result is a decreased quality of the semen is recovered either with penile vibratory stimulation (PVS) or with electroejaculation. Nowadays the therapeutic andrological approach of SCI men focuses on achievement of erectile function, recovery of spermatozoa and assisted reproductive technology. The first line of therapy recommended for infertility in SCI men is collection of semen via PVS with concomitant evaluation of total motile sperm yields for assisted conception which may include intravaginal insemination, intrauterine insemination, or in vitro fertilisation/intracytoplasmic sperm injection. Patients failing PVS may be referred for electroejaculation or surgical sperm retrieval.

show abstract

“…This is due in part to loss of descending inhibitory input from the brain to urethral sphincter motoneurons but also to changes in sphincter reflexes as a result of remodeling of spinal synapses (Beattie et al, 1993; Chang et al, 2007; Nout et al, 2006). In SCI rats DSD is associated with an increased tonic activity and reduced phasic activity of the sphincter electromyogram (Cheng and de Groat, 2004).…”

Section: Plasticity After Spinal Cord Injurymentioning

confidence: 99%

Plasticity in reflex pathways to the lower urinary tract following spinal cord injury

Groat

Yoshimura

2012

Experimental Neurology

130

140

View full text Add to dashboard Cite

The lower urinary tract has two main functions, storage and periodic expulsion of urine, that are regulated by a complex neural control system in the brain and lumbosacral spinal cord. This neural system coordinates the activity of two functional units in the lower urinary tract: (1) a reservoir (the urinary bladder) and (2) an outlet (consisting of bladder neck, urethra and striated muscles of the external urethra sphincter). During urine storage the outlet is closed and the bladder is quiescent to maintain a low intravesical pressure. During micturition the outlet relaxes and the bladder contracts to promote efficient release of urine. This reciprocal relationship between bladder and outlet is generated by reflex circuits some of which are under voluntary control. Experimental studies in animals indicate that the micturition reflex is mediated by a spinobulbospinal pathway passing through a coordination center (the pontine micturition center) located in the rostral brainstem. This reflex pathway is in turn modulated by higher centers in the cerebral cortex that are involved in the voluntary control of micturition. Spinal cord injury at cervical or thoracic levels disrupts voluntary control of voiding as well as the normal reflex pathways that coordinate bladder and sphincter function. Following spinal cord injury the bladder is initially areflexic but then becomes hyperreflexic due to the emergence of a spinal micturition reflex pathway. However the bladder does not empty efficiently because coordination between the bladder and urethral outlet is lost. Studies in animals indicate that dysfunction of the lower urinary tract after spinal cord injury is dependent in part on plasticity of bladder afferent pathways as well as reorganization of synaptic connections in the spinal cord. Reflex plasticity is associated with changes in the properties of ion channels and electrical excitability of afferent neurons and appears to be mediated in part by neurotrophic factors released in the spinal cord and/or the peripheral target organs.

show abstract

Evidence for Alterations of Synaptic Inputs to Sacral Spinal Reflex Circuits after Spinal Cord Transection in the Cat

Cited by 39 publications

References 0 publications

Assessment of Lower Urinary Tract Functional Deficit in Rats With Contusive Spinal Cord Injury

Assessment of Lower Urinary Tract Functional Deficit in Rats With Contusive Spinal Cord Injury

Erectile function and male reproduction in men with spinal cord injury: a review

Plasticity in reflex pathways to the lower urinary tract following spinal cord injury

Contact Info

Product

Resources

About