scholarly journals The Effects of Bisphenol A Exposure at Different Developmental Time Points in an Androgen-Sensitive Neuromuscular System in Male Rats

Endocrinology ◽  
2016 ◽  
Vol 157 (8) ◽  
pp. 2972-2977 ◽  
Author(s):  
Bryan A. Jones ◽  
Lydia S. Wagner ◽  
Neil V. Watson
Keyword(s):  
Bisphenol A ◽  
Motor Neurons ◽  
Developmental Time ◽  
Male Rats ◽  
Lumbar Spinal Cord ◽  
Sexually Dimorphic ◽  
Adult Rats ◽  
Soma Size ◽  
Neural Survival ◽  
Lumbar Spinal

The industrial plasticizer bisphenol A (BPA) is a ubiquitous endocrine disruptor to which the general human population is routinely exposed. Although BPA is well known as an estrogenic mimic, there have been some suggestions that this compound may also alter activity at the androgen receptor. To determine whether BPA does have antiandrogenic properties, we evaluated BPA effects in the spinal nucleus of the bulbocavernosus and dorsolateral nucleus, sexually dimorphic groups of motor neurons in the lumbar spinal cord that are critically dependent on androgens for survival and maintenance, as well as the monomorphic retrodorsolateral nucleus. In experiment 1, we administered varying concentrations of BPA to juvenile rats pre- and postnatally and examined both the number and size of motor neurons in adulthood. In experiment 2, different doses of BPA were given to adult rats for 28 days, after which the soma size of motor neurons were measured. Although no effect of BPA on neural survival or soma size was noted after perinatal BPA exposure, BPA exposure did result in a decrease in soma size in all motor neuron pools after chronic exposure in adulthood. These findings are discussed with regard to putative antiandrogenic effects of BPA; we argue that BPA is not antiandrogenic but is acting through nonandrogen receptor-dependent mechanisms.

scholarly journals High-Voltage Electron Microscopy Reveals Direct Synaptic Inputs from a Spinal Gastrin-Releasing Peptide System to Neurons of the Spinal Nucleus of Bulbocavernosus

Endocrinology ◽  
2010 ◽  
Vol 151 (1) ◽  
pp. 417-421 ◽  
Author(s):  
Hirotaka Sakamoto ◽  
Tatsuo Arii ◽  
Mitsuhiro Kawata
Keyword(s):  
Electron Microscopy ◽  
Spinal Cord ◽  
High Voltage ◽  
Lumbar Spinal Cord ◽  
Sexually Dimorphic ◽  
High Voltage Electron Microscopy ◽  
Synaptic Inputs ◽  
Gastrin Releasing Peptide ◽  
Voltage Electron ◽  
Lumbar Spinal

Abstract The spinal nucleus of bulbocavernosus (SNB) is a sexually dimorphic motor nucleus located in the anterior horn of the fifth and sixth lumbar segments of the spinal cord that plays a significant role in male sexual function. We recently found that a sexually dimorphic expression of gastrin-releasing peptide (GRP) in the lumbar spinal cord regulates male copulatory reflexes. Although it is reported that these systems are both profoundly regulated by circulating androgen levels in male rats, no direct evidence has been reported regarding GRP synaptic inputs onto SNB motoneurons. The aim of the current study was to determine the axodendritic synaptic inputs of spinal GRP neurons to SNB motoneurons. Immunoelectron microscopy, combined with a retrograde tracing technique using high-voltage electron microscopy (HVEM), provided a three-dimensional visualization of synaptic contacts from the GRP system in the lumbar spinal cord onto SNB motoneurons. HVEM analysis clearly demonstrated that GRP-immunoreactive axon terminals directly contact dendrites that extend into the dorsal gray commissure from the SNB. These HVEM findings provide an ultrastructural basis for understanding how the spinal GRP system regulates male sexual behavior.

scholarly journals Locomotor Training Increases Synaptic Structure With High NGL-2 Expression After Spinal Cord Hemisection

2019 ◽  
Vol 33 (3) ◽  
pp. 225-231 ◽  
Author(s):  
Kazu Kobayakawa ◽  
Kyleigh Alexis DePetro ◽  
Hui Zhong ◽  
Bau Pham ◽  
Masamitsu Hara ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Motor Neurons ◽  
Ventral Horn ◽  
Lumbar Spinal Cord ◽  
Locomotor Training ◽  
Synaptic Structure ◽  
Cord Injury ◽  
Lumbar Spinal ◽  
Spinal Cord Hemisection ◽  
Activity Dependent

Background. We previously demonstrated that step training leads to reorganization of neuronal networks in the lumbar spinal cord of rodents after a hemisection (HX) injury and step training, including increases excitability of spinally evoked potentials in hindlimb motor neurons. Methods. In this study, we investigated changes in RNA expression and synapse number using RNA-Seq and immunohistochemistry of the lumbar spinal cord 23 days after a mid-thoracic HX in rats with and without post-HX step training. Results. Gene Ontology (GO) term clustering demonstrated that expression levels of 36 synapse-related genes were increased in trained compared with nontrained rats. Many synaptic genes were upregulated in trained rats, but Lrrc4 (coding NGL-2) was the most highly expressed in the lumbar spinal cord caudal to the HX lesion. Trained rats also had a higher number of NGL-2/synaptophysin synaptic puncta in the lumbar ventral horn. Conclusions. Our findings demonstrate clear activity-dependent regulation of synapse-related gene expression post-HX. This effect is consistent with the concept that activity-dependent phenomena can provide a mechanistic drive for epigenetic neuronal group selection in the shaping of the reorganization of synaptic networks to learn the locomotion task being trained after spinal cord injury.

scholarly journals Tail Nerve Electrical Stimulation and Electro-Acupuncture Can Protect Spinal Motor Neurons and Alleviate Muscle Atrophy after Spinal Cord Transection in Rats

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Yu-Ting Zhang ◽  
Hui Jin ◽  
Jun-Hua Wang ◽  
Lan-Yu Wen ◽  
Yang Yang ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Electrical Stimulation ◽  
Muscle Atrophy ◽  
Motor Neurons ◽  
Lumbar Spinal Cord ◽  
Hindlimb Muscle ◽  
Neurotrophin 3 ◽  
Spinal Cord Segment ◽  
Cord Injury ◽  
Lumbar Spinal

Spinal cord injury (SCI) often results in death of spinal neurons and atrophy of muscles which they govern. Thus, following SCI, reorganizing the lumbar spinal sensorimotor pathways is crucial to alleviate muscle atrophy. Tail nerve electrical stimulation (TANES) has been shown to activate the central pattern generator (CPG) and improve the locomotion recovery of spinal contused rats. Electroacupuncture (EA) is a traditional Chinese medical practice which has been proven to have a neural protective effect. Here, we examined the effects of TANES and EA on lumbar motor neurons and hindlimb muscle in spinal transected rats, respectively. From the third day postsurgery, rats in the TANES group were treated 5 times a week and those in the EA group were treated once every other day. Four weeks later, both TANES and EA showed a significant impact in promoting survival of lumbar motor neurons and expression of choline acetyltransferase (ChAT) and ameliorating atrophy of hindlimb muscle after SCI. Meanwhile, the expression of neurotrophin-3 (NT-3) in the same spinal cord segment was significantly increased. These findings suggest that TANES and EA can augment the expression of NT-3 in the lumbar spinal cord that appears to protect the motor neurons as well as alleviate muscle atrophy.

scholarly journals Nimodipine Promotes Functional Recovery After Spinal Cord Injury in Rats

2021 ◽  
Vol 12 ◽  
Author(s):  
Fangliang Guo ◽  
Xiaolong Zheng ◽  
Ziyu He ◽  
Ruoying Zhang ◽  
Song Zhang ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Motor Neurons ◽  
Hind Limb ◽  
Term Treatment ◽  
Bladder Function ◽  
Lumbar Spinal Cord ◽  
Long Term Treatment ◽  
Cord Injury ◽  
Lumbar Spinal

Spinal cord injury (SCI) is a devastating condition that results in severe motor, sensory, and autonomic dysfunction. The L-/T-type calcium channel blocker nimodipine (NMD) exerts a protective effect on neuronal injury; however, the protective effects of long-term administration of NMD in subjects with SCI remain unknown. Thus, the aim of this study was to evaluate the role of long-term treatment with NMD on a clinically relevant SCI model. Female rats with SCI induced by 25 mm contusion were subcutaneously injected with vehicle or 10 mg/kg NMD daily for six consecutive weeks. We monitored the motor score, hind limb grip strength, pain-related behaviors, and bladder function in this study to assess the efficacy of NMD in rats with SCI. Rats treated with NMD showed improvements in locomotion, pain-related behaviors, and spasticity-like symptoms, but not in open-field spontaneous activity, hind limb grip strength or bladder function. SCI lesion areas and perilesional neuronal numbers, gliosis and calcitonin gene-related peptide (CGRP+) fiber sprouting in the lumbar spinal cord and the expression of K+–Cl− cotransporter 2 (KCC2) on lumbar motor neurons were also observed to further explore the possible protective mechanisms of NMD. NMD-treated rats showed greater tissue preservation with reduced lesion areas and increased perilesional neuronal sparing. NMD-treated rats also showed improvements in gliosis, CGRP+ fiber sprouting in the lumbar spinal cord, and KCC2 expression in lumbar motor neurons. Together, these results indicate that long-term treatment with NMD improves functional recovery after SCI, which may provide a potential therapeutic strategy for the treatment of SCI.

scholarly journals Effects of chronic spinal cord injury on relationships among ion channel and receptor mRNAs in mouse lumbar spinal cord

2018 ◽  
Author(s):  
Virginia B. Garcia ◽  
Matthew D. Abbinanti ◽  
Ronald M. Harris-Warrick ◽  
David J. Schulz
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Ion Channel ◽  
Motor Neurons ◽  
Receptor Expression ◽  
Lumbar Spinal Cord ◽  
Mrna Levels ◽  
Absolute Quantitation ◽  
Cord Injury ◽  
Lumbar Spinal

ABSTRACTSpinal cord injury (SCI) causes widespread changes in gene expression of the spinal cord, even in the undamaged spinal cord below the level of the lesion. Less is known about changes in the correlated expression of genes after SCI. We investigated gene co-expression networks among voltage-gated ion channel and neurotransmitter receptor mRNA levels using quantitative RT-PCR in longitudinal slices of the mouse lumbar spinal cord in control and chronic SCI animals. These longitudinal slices were made from the ventral surface of the cord, thus forming slices relatively enriched in motor neurons or interneurons. We performed absolute quantitation of mRNA copy number for 50 ion channel or receptor transcripts from each sample, and used multiple correlation analyses to detect patterns in correlated mRNA levels across all pairs of genes. The majority of channels and receptors changed in expression as a result of chronic SCI, but did so differently across slice levels. Furthermore, motor neuron enriched slices experienced an overall loss of correlated channel and receptor expression, while interneuron slices showed a dramatic increase in the number of positively correlated transcripts. These correlation profiles suggest that spinal cord injury induces distinct changes across cell types in the organization of gene co-expression networks for ion channels and transmitter receptors.

scholarly journals Spinal Cord Injury Causes Reduction of Galanin and Gastrin Releasing Peptide mRNA Expression in the Spinal Ejaculation Generator of Male Rats

2021 ◽  
Vol 12 ◽  
Author(s):  
James W. Wiggins ◽  
Jonathan E. Sledd ◽  
Lique M. Coolen
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Male Rats ◽  
Lumbar Spinal Cord ◽  
Gastrin Releasing Peptide ◽  
Cord Injury ◽  
Contusion Injury ◽  
Spinal Contusion ◽  
Lumbar Spinal ◽  
Injury Causes

Spinal cord injury (SCI) in men is commonly associated with sexual dysfunction, including anejaculation, and chronic mid-thoracic contusion injury in male rats also impairs ejaculatory reflexes. Ejaculation is controlled by a spinal ejaculation generator consisting of a population of lumbar spinothalamic (LSt) neurons that control ejaculation through release of four neuropeptides including galanin and gastrin releasing peptide (GRP) onto lumbar and sacral autonomic and motor nuclei. It was recently demonstrated that spinal contusion injury in male rats caused reduction of GRP-immunoreactivity, but not galanin-immunoreactivity in LSt cells, indicative of reduced GRP peptide levels, but inconclusive results for galanin. The current study further tests the hypothesis that contusion injury causes a disruption of GRP and galanin mRNA in LSt cells. Male rats received mid-thoracic contusion injury and galanin and GRP mRNA were visualized 8 weeks later in the lumbar spinal cord using fluorescent in situ hybridization. Spinal cord injury significantly reduced GRP and galanin mRNA in LSt cells. Galanin expression was higher in LSt cells compared to GRP. However, expression of the two transcripts were positively correlated in LSt cells in both sham and SCI animals, suggesting that expression for the two neuropeptides may be co-regulated. Immunofluorescent visualization of galanin and GRP peptides demonstrated a significant reduction in GRP-immunoreactivity, but not galanin in LSt cells, confirming the previous observations. In conclusion, SCI reduced GRP and galanin expression in LSt cells with an apparent greater impact on GRP peptide levels. GRP and galanin are both essential for triggering ejaculation and thus such reduction may contribute to ejaculatory dysfunction following SCI in rats.

Sign in / Sign up

Export Citation Format

Share Document