Recently, we demonstrated a spinal GABA(A) receptor (GABA(A)R)-dependent inhibition on the induction of repetitive stimulation-induced spinal reflex potentiation. However, it remains unclear whether steroid hormones modulate such an inhibition. Here, we show that progesterone is capable of producing GABA(A)Rs-dependent inhibition of the induction of spinal reflex potentiation by actions through neurosteroid metabolites. Progesterone (5mg/kg, twice daily for 4 days) up-regulates the expression of GABA(A)R alpha2, alpha3, alpha4 and delta subunits, and is associated with attenuated repetitive stimulation-induced spinal reflex activity in ovariectomized rats. These changes were blocked by finasteride (50mg/kg, twice daily), an antagonist of neurosteroid synthesis from progesterone, but not by the progesterone receptor antagonist, RU486 (100mg/kg, twice daily). The induction of spinal reflex potentiation was attenuated after a short (30 min) intrathecal treatment with the neurosteroids, allopregnanolone (ALLOP, 10 microM, 10 microL) and 3 alpha,5 alpha-tetrahydrodeoxycorticosterone (THDOC, 10 microM, 10 microL). Acute intrathecal administration of the GABA(A)R antagonist, bicuculline (10 microM, 10 microL) reversed the inhibition produced by progesterone, THDOC and allopregnanolone. These results imply that progesterone-mediated effects on GABA(A)R expression and neural inhibition are regulated by neurosteroids synthesis rather than progesterone receptor activation.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.pain.2008.12.023 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Complex Regional Pain Syndrome: Diagnosis, Pathophysiology, and Treatment Approaches.
Cureus
December 2024
Neurosurgery, Fluminense Federal University, Niterói, BRA.
Complex regional pain syndrome (CRPS) is a chronic pain condition characterized by significant sensory, motor, and autonomic dysfunction, often following trauma or nerve injury. Historically known as causalgia and reflex sympathetic dystrophy, CRPS manifests as severe, disproportionate pain, often accompanied by hyperalgesia, allodynia, trophic changes, and motor impairments. Classified into type I (without nerve injury) and type II (associated with nerve damage), CRPS exhibits a complex pathophysiology involving peripheral and central sensitization, neurogenic inflammation, maladaptive brain plasticity, and potential autoimmune and psychological influences.
View Article and Find Full Text PDFOptimal sigmoid function models for analysis of transspinal evoked potential recruitment curves recorded from different muscles.
PLoS One
January 2025
Klab4Recovery Research Program, The City University of New York, Staten Island, New York, United States of America.
Recruitment input-output curves of transspinal evoked potentials that represent the net output of spinal neuronal networks during which cortical, spinal and peripheral inputs are integrated as well as motor evoked potentials and H-reflexes are used extensively in research as neurophysiological biomarkers to establish physiological or pathological motor behavior and post-treatment recovery. A comparison between different sigmoidal models to fit the transspinal evoked potentials recruitment curve and estimate the parameters of physiological importance has not been performed. This study sought to address this gap by fitting eight sigmoidal models (Boltzmann, Hill, Log-Logistic, Log-Normal, Weibull-1, Weibull-2, Gompertz, Extreme Value Function) to the transspinal evoked potentials recruitment curves of soleus and tibialis anterior recorded under four different cathodal stimulation settings.
View Article and Find Full Text PDFNeuromuscular factors predicting lower limb explosive strength in male college sprinters.
Front Physiol
January 2025
Sports Science School, Beijing Sport University, Beijing, China.
Purpose: This study aimed to explore the effects of neural and muscular factors on lower limb explosive strength in male college sprinters, and build models based on those factors to identify the key neuromuscular factors that predict the rate of force development (RFD) and 30 m sprint time.
Method: 15 male college sprinters were recruited in this study, with 100 m personal best times under 10.93 s.
Knee Pain Is Not Always the Knee.
JBJS Rev
January 2025
Adult Reconstruction, Orthopedic Surgery Department, Lenox Hill Hospital Northwell Health, New York, New York.
» Lumbar spine pathology is a known cause of referred pain to the lower extremities and should be investigated as a possible source of knee pain, especially with patients in their sixth decade.» While primary knee pathology is common, spinal pathology should always be considered in older patients presenting with knee pain, especially in atraumatic cases where knee imaging does not correlate with complaints or examination findings.» Lumbar (L) 3-4 pathology is most commonly affected in referred knee pain, with the 2 most common pathologies being spinal stenosis and disc herniation.
View Article and Find Full Text PDFMedial and lateral vestibulospinal projections to the cervical spinal cord of the squirrel monkey.
Front Neurol
January 2025
Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR, United States.
Introduction: The brainstem vestibular nuclei neurons receive synaptic inputs from inner ear acceleration-sensing hair cells, cerebellar output neurons, and ascending signals from spinal proprioceptive-related neurons. The lateral (LVST) and medial (MVST) vestibulospinal (VS) tracts convey their coded signals to the spinal circuits to rapidly counter externally imposed perturbations to facilitate stability and provide a framework for self-generated head movements.
Methods: The present study describes the morphological characteristics of intraaxonally recorded and labeled VS neurons monosynaptically connected to the 8th nerve.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!