Morphological changes of cholinergic nerve fibers in the urinary bladder after establishment of artificial somatic-autonomic reflex arc in rats.
OBJECTIVE
To establish an artificial somatic-autonomic reflex arc in rats and observe the following distributive changes of neural fibers in the bladder.


METHODS
Adult Sprague-Dawley rats were randomly divided into three groups: control group, spinal cord injury (SCI) group, and reinnervation group. DiI retrograde tracing was used to verify establishment of the model and to investigate the transport function of the regenerated efferent axons in the new reflex arc. Choline acetyltransferase (ChAT) in the DiI-labeled neurons was detected by immunohistochemistry. Distribution of neural fibers in the bladder was observed by acetylcholine esterase staining.


RESULTS
DiI-labeled neurons distributed mainly in the left ventral horn from L3 to L5, and some of them were also ChAT-positive. The neural fibers in the bladder detrusor reduced remarkably in the SCI group compared with the control (P < 0.05). After establishment of the somatic-autonomic reflex arc in the reinnervation group, the number of ipsilateral fibers in the bladder increased markedly compared with the SCI group (P < 0.05), though still much less than that in the control (P < 0.05).


CONCLUSIONS
The efferent branches of the somatic nerves may grow and replace the parasympathetic preganglionic axons through axonal regeneration. Acetylcholine is still the major neurotransmitter of the new reflex arc. The controllability of detrusor may be promoted when it is reinnervated by the pelvic ganglia efferent somatic motor fibers from the postganglionic axons.
Wang
Han-Zhi
HZ
Department of Neurobiology, Third Military Medical University, Chongqing 400038, China.
Li
Shu-Rong
SR
Wen
Can
C
Xiao
Chuan-Guo
CG
Su
Bing-Yin
BY
D000110:Acetylcholinesterase / Q000096:biosynthesis; D000714:Anastomosis, Surgical; D000818:Animals; D001339:Autonomic Fibers, Preganglionic / Q000502:physiology*; D002799:Cholinergic Fibers / Q000378:metabolism*; D007150:Immunohistochemistry; D009046:Motor Neurons / Q000166:cytology* / Q000378:metabolism; D009416:Nerve Regeneration / Q000502:physiology; D009434:Neural Pathways / Q000166:cytology* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012018:Reflex / Q000502:physiology*; D013119:Spinal Cord Injuries / Q000503:physiopathology; D013126:Spinal Nerve Roots / Q000601:surgery; D001743:Urinary Bladder / Q000294:innervation* / Q000502:physiology / Q000601:surgery; D001750:Urinary Bladder, Neurogenic / Q000601:surgery
D000110:Acetylcholinesterase