The purpose of the study was to investigate whether the small fiber-evoked dorsal root reflex (DRR) can be obtained by electrical stimulation of the peripheral nerve in rats. Fifty-one DRRs were recorded from different kinds of fiber filaments in the proximal ends of the cut L(5) dorsal root following electrical stimulation of the sural nerve. According to the kind of afferent fibers in the sural nerve associated with the DRRs from dorsal root, these DRRs were divided into five different types: A(alphabeta) fiber-evoked A(alphabeta).DRR (A(alphabeta)- A(alphabeta).DRR), A(betadelta) - A(delta ).DRR, A(betadelta)-C.DRR, A(alphabetadelta)-C.DRR and C-C.DRR. The results obtained show that the DRR can be obtained from either A-fibers (including A(delta )-fibers) or C-fibers of dorsal root filaments by stimulation of the sural nerve. It is therefore suggested that either A(delta ).DRR or C.DRR can be used as a validity index of presynaptic inhibition of the thin primary afferent terminals for investigation of the modulation mechanisms of peripheral effectors.
Afferent Pathways ; Animals ; Electric Stimulation ; Female ; Male ; Nerve Fibers, Myelinated ; physiology ; Nerve Fibers, Unmyelinated ; physiology ; Rats ; Rats, Sprague-Dawley ; Reflex ; physiology ; Spinal Nerve Roots ; physiology ; Sural Nerve ; physiology

Peripheral nerve injury often results in abnormal neuropathic pain such as allodynia or hyperalgesia. Acupuncture, a traditional Oriental medicine, has been used to relieve pain and related symptoms. However, the efficiency of acupuncture in relieving neuropathic pain is not clear. The aim of this study was to investigate the anti-allodynic effects of acupuncture through behavioral and electrophysiological examinations. Male Sprague-Dawley rats were subjected to neuropathic surgery consisting of a tight ligation and transection of the left tibial and sural nerves, under pentobarbital anesthesia. The acupuncture experiment consisted of four different groups, one treated at each of three different acupoints (Zusanli (ST36), Yinlingquan (SP9), and a sham-acupoint) and a control group. Behavioral tests for mechanical allodynia and cold allodynia were performed for up to two weeks postoperatively. Extracellular electrophysiological recordings were made from the dorsal roots using platinum wire electrodes. Mechanical and cold allodynia were significantly reduced after acupuncture treatment at the Zusanli and Yinlingquan acupoints, respectively. Electrophysiological neural responses to von Frey and acetone tests were also reduced after acupuncture at the same two acupoints. These results suggest that acupuncture may be beneficial in relieving neuropathic pain.
Spinal Nerve Roots/*physiology ; Rats, Sprague-Dawley ; Rats ; Neuralgia/physiopathology/*therapy ; Male ; Electrophysiology ; Animals ; *Acupuncture Analgesia

Peripheral nerve injury often results in abnormal neuropathic pain such as allodynia or hyperalgesia. Acupuncture, a traditional Oriental medicine, has been used to relieve pain and related symptoms. However, the efficiency of acupuncture in relieving neuropathic pain is not clear. The aim of this study was to investigate the anti-allodynic effects of acupuncture through behavioral and electrophysiological examinations. Male Sprague-Dawley rats were subjected to neuropathic surgery consisting of a tight ligation and transection of the left tibial and sural nerves, under pentobarbital anesthesia. The acupuncture experiment consisted of four different groups, one treated at each of three different acupoints (Zusanli (ST36), Yinlingquan (SP9), and a sham-acupoint) and a control group. Behavioral tests for mechanical allodynia and cold allodynia were performed for up to two weeks postoperatively. Extracellular electrophysiological recordings were made from the dorsal roots using platinum wire electrodes. Mechanical and cold allodynia were significantly reduced after acupuncture treatment at the Zusanli and Yinlingquan acupoints, respectively. Electrophysiological neural responses to von Frey and acetone tests were also reduced after acupuncture at the same two acupoints. These results suggest that acupuncture may be beneficial in relieving neuropathic pain.
Spinal Nerve Roots/*physiology ; Rats, Sprague-Dawley ; Rats ; Neuralgia/physiopathology/*therapy ; Male ; Electrophysiology ; Animals ; *Acupuncture Analgesia

Sciatic nerve injury is a common disease of peripheral nerve in clinic. After nerve injury, there are many dysfunctions in motoneurons and muscles following regeneration. Previous studies mostly investigated the aspects related to the injured nerve, and the effect on the recurrent inhibition (RI) pathway of spine following regeneration was not fully understood. Following reinnervation after temporary sciatic nerve crush, the functional alteration of RI was studied. In adult rats, RI between lateral gastrocnemius-soleus (LG-S) and medial gastrocnemius (MG) motor pools was assessed by conditioning monosynaptic reflexes (MSRs) elicited from the cut dorsal roots and recorded from either the LG-S or MG nerves by antidromic stimulation of the synergist muscle nerve. The following results were obtained. (1) The RI of MSRs in rats was almost lost (<5 weeks) after sciatic nerve crush. Although the RI partially recovered following reinnervation (6 weeks), it remained permanently depressed (up to 14 weeks). (2) Sciatic nerve crush on one side did not affect the contralateral RI. (3) Sciatic nerve crush did not induce any motoneuron loss revealed by immunohistochemistry. Peripheral nerve temporary disconnection causes long term alterations in RI pathway which make up motoneuron's function enhance for the alteration of muscle power and suggests that peripheral nerve injury induces long term plastic changes in the spinal motoneuron circuitry.
Animals ; Long-Term Synaptic Depression ; physiology ; Male ; Motor Neurons ; physiology ; Nerve Crush ; Nerve Regeneration ; physiology ; Neuronal Plasticity ; physiology ; Neurons, Afferent ; physiology ; Rats ; Rats, Wistar ; Reflex, Monosynaptic ; physiology ; Sciatic Nerve ; injuries ; physiopathology ; Spinal Cord ; physiopathology ; Spinal Nerve Roots ; physiopathology

OBJECTIVETo investigate the compensative mechanism of no further impairment of the upper limb after ipsilateral C(7) transfer for treatment of root avulsion of C(5)-C(6) of the brachial plexus.

METHODSSixty Sprague Dawley (SD) rats were randomly divided into a C7-transection group and a control group, 30 rats each. In the C(7)-transection group, the left forelimbs of the animals underwent transection of ipsilateral C(7) nerve root while C(5) and C(6) nerve roots were avulsed. In the control group, the left forelimbs only underwent C(5) and C(6) root avulsion. The representative muscles of C(7) (innervated mainly by C(7)) including latissimus dorsi, triceps, extensor carpi radialis brevis and extensor digitorum communis were evaluated with neurophysiological investigation, muscular histology and motor end plate histomorphometry 3, 6 and 12 weeks after operation. The right forelimbs of all rats were taken as the control sides.

RESULTSThree weeks after operation, the recovery rates of amplitudes of compound muscle action potential (CMAP) and CMAP latency, muscular wet weight and cross-sectional area of muscle fibers, and area of postsynaptic membranes of those four representative muscles in the C(7)-transection group were significantly lower than those of the control group (P less than 0.05 or P less than 0.01). Six weeks postoperatively, the recovery rates of CMAP amplitude and latency of the triceps showed no significant difference between the C(7)-transection group and the control group (P larger than 0.05). For the extensor carpi radialis brevis and the extensor digitorum communis, the recovery rates of the cross-sectional area of muscle fibers, the amplitude and latency of CMAP and the area of postsynaptic membranes showed no significant difference between the two groups (P larger than 0.05), while the rest parameters were still significantly different between the two group (P less than 0.05 or P less than 0.01). As far as the ultramicrostructure was concerned in the C(7)-transection group, more motor end plates of four representative muscles were observed and their ultramicrostructure also had a tendency to mature as compared with those of 3 weeks postoperatively. Twelve weeks after operation, all parameters of the C(7)-transection group were not significantly different from those of the control group (P >0.05). In the C7-transection group, the motor end plates were densely distributed and their ultramicrostructure in four representative muscles appeared to be mature as compared with those of the control group.

CONCLUSIONSAfter ipsilateral C(7) transfer for treatment of root avulsion of C(5)-C(6) of the brachial plexus, the nerve fibers of the lower trunk can compensatively innervate fibers of C(7)-representative muscles by means of motor end plate regeneration, so there is no further impairment on the injured upper limb.

Animals ; Brachial Plexus ; injuries ; surgery ; Motor Endplate ; ultrastructure ; Nerve Transfer ; methods ; Rats ; Rats, Sprague-Dawley ; Spinal Nerve Roots ; injuries ; Upper Extremity ; physiology

OBJECTIVETo establish an artificial somatic-autonomic reflex arc in rats and observe the following distributive changes of neural fibers in the bladder.

METHODSAdult 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.

RESULTSDiI-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).

CONCLUSIONThe 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.

Acetylcholinesterase ; biosynthesis ; Anastomosis, Surgical ; Animals ; Autonomic Fibers, Preganglionic ; physiology ; Cholinergic Fibers ; metabolism ; Immunohistochemistry ; Motor Neurons ; cytology ; metabolism ; Nerve Regeneration ; physiology ; Neural Pathways ; cytology ; metabolism ; Rats ; Rats, Sprague-Dawley ; Reflex ; physiology ; Spinal Cord Injuries ; physiopathology ; Spinal Nerve Roots ; surgery ; Urinary Bladder ; innervation ; physiology ; surgery ; Urinary Bladder, Neurogenic ; surgery

OBJECTIVE: To evaluate the diagnostic value of somatosensory evoked potential(SEP) in lumbosacral disc herniation(LDH). METHODS: Posterior tibial nerve somatosensory evoked potential(PTNSEP) and dermatomal somatosensory evoked potential (DSEP) were recorded from 60 patients with radiculopathy caused by LDH and 30 healthy subjects. RESULTS: DSEP was abnormal in 56 cases (93.3%) and PTNSEP was abnormal in 26 cases (43.3%). The significant difference was observed (P<0.001). The abnormality of DSEP from L4 dermatome was detected mainly in patients with L3-4 LDH, the abnormality of DSEP from L5 dermatome was detected mainly in patients with L4-5 LDH, the abnormality of DSEP from L5S1 dermatome was detected mainly in patients with S1 LDH. DSEP can reflect the compressed extent of nerve root. CONCLUSIONS There was a good correlation of DSEP with lumbosacral nerve root injury,which supplement the information that can not be provided by imaging examingation. DSEP is a sensitive electrophysic method that not only is used to evaluate single nerve root function, but also is helpful in the location of the lesion.
Adult ; Electric Stimulation ; Electrodiagnosis/methods* ; Evoked Potentials, Somatosensory ; Female ; Forensic Medicine ; Humans ; Intervertebral Disc Displacement/physiopathology* ; Lumbar Vertebrae ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Sensitivity and Specificity ; Spinal Nerve Roots/physiopathology* ; Tibial Nerve/physiology*

OBJECTIVETo evaluate the erectile and ejaculatory function of sacral tumor patients after sacral nerve root resection and investigate the relationship of erectile and ejaculatory dysfunction (EED) with the level of sacral nerve injury.

METHODSThis retrospective study included 47 male patients aged 16 to 63 (32.6 +/- 6.8) years treated by sacral tumor resection between January 2008 and August 2013. According to the levels of the sacral nerve roots spared in surgery, the patients were divided into four groups: bilateral S1-S3 (n=16), unilateral S1-S3 (n=21), unilateral S1-S2 (n=6), and unilateral S1 (n=4). The patients were followed up for 12 to 41 (27.2 +/- 10.9) months by questionnaire investigation, clinic review, and telephone calls about their erectile and ejaculatory function at 3, 6 and 12 months after surgery and in August 2013.

RESULTSIn the bilateral S1-S3 group, the incidence rates of EED were 31.25% (5/16), 25% (4/16), and 12.5% (2/16) at 3, 6, and 12 months respectively after surgery, with recovery of erectile and ejaculatory function in August 2013. The incidence rates of EED in the unilateral S1-S3 group were 85.71% (18/21), 71.43% (15/21), 52.38% (11/21), and 42.86% (9/21) at 3, 6 and 12 months and in August 2013, respectively; those in the unilateral S1-S2 group were 100% (6/6), 83.33% (5/6), 83.33% (5/6), and 66.67% (4/6) at the four time points; and those in the unilateral S1 group were all 100% (4/4). No statistically significant differences were found in the incidence rate of EED among the patients of different ages or tumor types (P > 0.05).

CONCLUSIONThe incidence of postoperative EED in male patients treated by sacral tumor resection is closely related to the mode of operation. Sparing the S3 nerve root at least unilaterally in sacral tumor resection is essential for protecting the erectile and ejaculatory function of the patient.

Adolescent ; Adult ; Ejaculation ; physiology ; Erectile Dysfunction ; epidemiology ; etiology ; Female ; Humans ; Incidence ; Male ; Middle Aged ; Organ Sparing Treatments ; Peripheral Nervous System Neoplasms ; surgery ; Postoperative Complications ; epidemiology ; Postoperative Period ; Retrospective Studies ; Sacrum ; Spinal Nerve Roots ; injuries ; surgery ; Surveys and Questionnaires ; Young Adult