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1.
Neurology ; 72(4): 317-23, 2009 Jan 27.
Article in English | MEDLINE | ID: mdl-19171827

ABSTRACT

OBJECTIVE: We examined the effect of aerobic exercise in patients with spinal and bulbar muscular atrophy (SBMA). SBMA is caused by a defect androgen receptor. This defect causes motor neuron death, but considering the important function of androgens in muscle, it is possible that muscle damage in SBMA also occurs independently of motor neuron damage. METHODS: Eight patients with SBMA engaged in regular cycling exercise for 12 weeks. Maximum oxygen uptake (Vo(2max)), maximal work capacity (W(max)), muscle morphology, citrate synthase (CS) activity, body composition, EMG, static strength measurements, lung function, plasma proteins, and hormones were evaluated before and after training. Evaluation of improvements in activities of daily living (ADL) was conducted after training. RESULTS: W(max) increased by 18%, and CS activity increased by 35%. There was no significant change in Vo(2max) or any of the other variables examined before and after training, and the patients with SBMA did not feel improvements in ADL. CONCLUSIONS: Frequent, moderate-intensity aerobic conditioning is of little beneficial effect in patients with spinal and bulbar muscular atrophy (SBMA). High levels of plasma creatine kinase and muscle regeneration indicate a primary myopathic affection, which, in parallel with the motor neuron deficiency, may attenuate the response to exercise training in patients with SBMA.


Subject(s)
Bulbo-Spinal Atrophy, X-Linked/physiopathology , Bulbo-Spinal Atrophy, X-Linked/therapy , Exercise Therapy/methods , Exercise/physiology , Activities of Daily Living/psychology , Bulbo-Spinal Atrophy, X-Linked/psychology , Female , Humans , Male , Middle Aged , Muscular Atrophy, Spinal/physiopathology , Muscular Atrophy, Spinal/psychology , Muscular Atrophy, Spinal/therapy , Oxygen Consumption/physiology
2.
Exp Brain Res ; 181(1): 193-7, 2007 Jul.
Article in English | MEDLINE | ID: mdl-17571255

ABSTRACT

If reduced reciprocal inhibition plays a causal role in the pathophysiology of spasticity as has been suggested in several studies, the inhibition is expected to be impaired in spastic, but not in normal muscles. Patients with neurolathyrism offer a possibility of testing this prediction since the spastic symptoms in these patients are restricted to the lower extremities only. Three patients with neurolathyrism were tested. Their data were compared with 15 age-matched healthy subjects. All patients showed signs of spasticity in the legs. Two patients had normal voluntary muscle force in the lower extremities and one had decreased force. No clinical abnormalities were found in the upper extremities. Reciprocal inhibition between ankle dorsiflexor and plantarflexor muscles was absent in all patients, whereas the inhibition between wrist extensor and flexor muscles was present and of normal size and latency. These findings are consistent with the hypothesis that reduced reciprocal inhibition plays a causal role in the pathophysiology of spasticity.


Subject(s)
Extremities , Lathyrism/pathology , Muscle Spasticity/physiopathology , Neural Inhibition/physiology , Aged , Electric Stimulation/methods , Electromyography/methods , Evoked Potentials, Motor/physiology , Evoked Potentials, Motor/radiation effects , Female , Humans , Lathyrism/complications , Male , Peroneal Nerve/physiopathology , Peroneal Nerve/radiation effects , Radial Nerve/physiopathology , Radial Nerve/radiation effects , Reaction Time/physiology , Reaction Time/radiation effects , Transcranial Magnetic Stimulation/methods
3.
Acta Physiol (Oxf) ; 189(2): 171-80, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17250567

ABSTRACT

Spasticity is a term, which was introduced to describe the velocity-sensitive increased resistance of a limb to manipulation in subjects with lesions of descending motor pathways. This distinguishes spasticity from the changes in passive muscle properties, which are often seen in these patients, but are not velocity-sensitive. Increased excitability of the stretch reflex is thus a central component of the definition of spasticity. This review describes changes in cellular properties and transmission in a number of spinal reflex pathways, which may explain the increased stretch reflex excitability. The review focuses mainly on results derived from the use of non-invasive electrophysiological techniques, which have been developed during the past 20-30 years to investigate spinal neuronal networks in human subjects, but work from animal models is also considered. The reflex hyperexcitability develops over several months following the primary lesion and involves adaptation in the spinal neuronal circuitries caudal to the lesion. In animal models, changes in cellular properties (such as 'plateau potentials') have been reported, but the relevance of these changes to human spasticity has not been clarified. In humans, numerous studies have suggested that reduction of spinal inhibitory mechanisms (in particular that of disynaptic reciprocal inhibition) is involved. The inter-subject variability of these mechanisms and the lack of objective quantitative measures of spasticity have impeded disclosure of a clear causal relationship between the alterations in the inhibitory mechanisms and the stretch reflex hyperexcitability. Techniques which make such a quantitative measure possible as well as longitudinal studies where development of reflex excitability and changes in the inhibitory mechanisms are followed over time are in great demand.


Subject(s)
Muscle Spasticity/physiopathology , Spinal Cord/physiopathology , Evoked Potentials, Motor/physiology , Humans , Motor Neurons/physiology , Movement/physiology , Muscle Spindles/metabolism , Muscle Spindles/physiopathology , Muscle, Skeletal/physiopathology , Neural Inhibition/physiology , Neural Pathways/physiopathology , Neurons, Afferent/physiology , Neurotransmitter Agents/metabolism , Reflex/physiology , Spinal Cord Injuries/physiopathology
4.
Arch Womens Ment Health ; 8(2): 105-11, 2005 Jun.
Article in English | MEDLINE | ID: mdl-15883650

ABSTRACT

The epidemic of drug and alcohol abuse in our nation impacts millions of women, mothers, and children. Addicted mothers with complex problems and numerous co-morbidities present unique treatment challenges. This intergenerational cycle of abuse and addiction is difficult to stop. Arkansas CARES (Center for Addictions Research Education and Services, referred to in this article as CARES) initially was created to treat addicted pregnant and postpartum women and their infants. CARES evolved into a residential treatment program for dually diagnosed mothers with their children. This paper is a synopsis of a presentation delivered at the North American Society for Psychosocial Obstetrics and Gynecology. It shares a glimpse inside the treatment program and lessons learned along the way in an effort to assist others who are interested in building treatment programs for addicted women with their children.


Subject(s)
Child Welfare/statistics & numerical data , Maternal Health Services/organization & administration , Maternal Welfare/statistics & numerical data , Substance Abuse Treatment Centers/organization & administration , Substance-Related Disorders/rehabilitation , Adult , Aged , Alcoholism/rehabilitation , Child , Female , Humans , Patient Education as Topic/organization & administration , Pregnancy , Pregnancy Complications/prevention & control , Pregnancy Outcome/epidemiology , Program Development , Quality Assurance, Health Care/organization & administration , Smoking Cessation/methods , Substance-Related Disorders/prevention & control
5.
Brain ; 127(Pt 12): 2693-702, 2004 Dec.
Article in English | MEDLINE | ID: mdl-15509621

ABSTRACT

The pathophysiological mechanisms underlying the development of spasticity are not clear, but the excitability of the disynaptic reciprocal inhibitory pathway is affected in many patients with spasticity of different origin. Patients with genetically identified autosomal dominant pure spastic paraparesis (ADPSP) develop spasticity and paresis in the legs, but usually have no symptoms in the arms. Comparison of the spinal and supraspinal control of the legs and arms in these patients may therefore provide valuable information about the pathophysiology of spasticity. In the present study, we tested the hypothesis that one of the pathophysiological mechanisms of spasticity in these patients is abnormal corticospinal transmission and that this may lead to decreased reciprocal inhibition. Ten patients and 15 healthy age-matched control subjects were investigated. The patients were all spastic in the legs (with hyperactive tendon reflexes, increased muscle tone and Babinski sign), but had no neurological symptoms in the arms (except for one patient). Disynaptic reciprocal Ia inhibition of flexor carpi radialis (FCR) and soleus (SOL) motoneurons was measured (as the depression of the background FCR and SOL EMG activity and as the short latency inhibition of the FCR and SOL H-reflex evoked by radial and peroneal nerve stimulation). In addition, the latency of motor evoked potentials (MEPs) in the FCR muscle and the tibialis anterior (TA) muscle was measured. In the patients, the mean reciprocal inhibition was normal in the arms, while it was significantly decreased in the leg compared with the healthy subjects. In the patients, the average latency of MEPs in the FCR muscle was normal, while the latency to the MEP in TA muscle was significantly longer than that found in healthy subjects. Four patients, however, differed from the other patients by having significant reciprocal inhibition in the leg and a significantly shorter latency of TA MEPs than found in the other patients. The six patients without reciprocal inhibition in the leg instead had significant short latency facilitation of the SOL H-reflex and a longer TA MEP latency than seen in the healthy subjects and in the four patients with retained reciprocal inhibition. These findings support the hypothesis that disynaptic reciprocal inhibition and short latency facilitation are involved in the development of spasticity and, furthermore, they suggest a positive correlation between impairment of corticospinal transmission and decrease of reciprocal inhibition/appearance of reciprocal facilitation.


Subject(s)
Arm/innervation , Leg/innervation , Neural Inhibition , Paraparesis, Spastic/physiopathology , Pyramidal Tracts/physiopathology , Adult , Electric Stimulation/methods , Electromyography , Evoked Potentials, Motor , Female , Genes, Dominant , H-Reflex , Humans , Magnetics , Male , Middle Aged , Paraparesis, Spastic/genetics , Peroneal Nerve/physiopathology , Radial Nerve/physiopathology , Reaction Time , Synaptic Transmission
6.
Brain ; 126(Pt 2): 495-507, 2003 Feb.
Article in English | MEDLINE | ID: mdl-12538415

ABSTRACT

The purpose of the present study was to investigate the pathophysiological role of reciprocal facilitation between antagonistic motoneuron pools in spasticity. The soleus H-reflex was conditioned by prior stimulation of the peroneal nerve in 15 healthy subjects, six hemiplegic patients and 11 spinal cord injured (SCI) patients. The hemiplegic patients were tested from soon after the onset of hemiplegia and up to 2 years later. Whereas stimulation of the peroneal nerve produced short-latency inhibition of the soleus H-reflex in healthy subjects, it produced facilitation in spastic SCI and hemiplegic patients. This facilitation was demonstrated to have a low threshold compatible with activation of group I afferents and was most likely mediated by an oligosynaptic (reciprocal) excitatory pathway. The facilitation appeared in parallel with the development of hyperactive Achilles tendon reflexes, which was the only clinical finding that could be correlated positively with the facilitation. It is suggested that the appearance of reciprocal excitation plays a role in the pathophysiology of spasticity.


Subject(s)
Ankle Joint/physiopathology , Hemiplegia/physiopathology , Muscle, Skeletal/physiopathology , Spinal Cord Injuries/physiopathology , Achilles Tendon/physiopathology , Adult , Afferent Pathways/physiopathology , Aged , Electric Stimulation/methods , Female , Follow-Up Studies , H-Reflex , Humans , Male , Middle Aged , Muscle, Skeletal/innervation , Peroneal Nerve/physiopathology , Reaction Time
7.
J Physiol ; 544(2): 631-40, 2002 10 15.
Article in English | MEDLINE | ID: mdl-12381832

ABSTRACT

Normal coordinated movement requires that the activity of antagonistic motoneurones may be depressed at appropriate times during the movement. Both glycinergic and GABAergic inhibitory mechanisms participate in this control. Patients with the major form of hyperekplexia (hereditary startle disease) have impaired inhibition of spinal motoneurones from local glycinergic interneurones and represent an ideal opportunity for studying the role of glycinergic inhibition in the control of antagonistic muscles. In the present study we investigated whether impaired glycinergic inhibition affects the corticospinal control of antagonistic spinal motoneurones in 10 patients with hyperekplexia and whether there are mechanisms that may compensate for the lack of glycinergic inhibition. In healthy subjects transcranial magnetic stimulation (TMS) produced a short-latency inhibition of the soleus H-reflex at rest and during tonic dorsiflexion. This inhibition, which has been shown to be mediated by spinal (glycinergic) inhibitory interneurones, was absent in all four patients in whom this experiment was performed. This confirms that glycinergic transmission is impaired in the patients. During voluntary dorsiflexion subthreshold TMS produced a depression of the ongoing EMG activity in the tibialis anterior (TA) muscle in both healthy subjects and all of the six tested patients. This is consistent with the idea that this EMG depression is caused by activation of cortical (GABAergic) inhibitory interneurones. Cross-correlation analysis revealed normal short-term synchronization of TA motor units accompanied by coherence in the 8-12 Hz and 18-35 Hz frequency bands in the 10 patients. As in healthy subjects, 8-12 Hz coherence accompanied by decreased tendency to discharge synchronously (de-synchronization) was found in recordings from the antagonistic TA and soleus muscles in 2 of the 10 patients. This suggests that glycinergic inhibition is not responsible for de-synchronization of antagonistic motor units, but that other GABAergic-inhibitory mechanisms must be involved. We propose that such mechanisms may compensate for the lack of glycinergic reciprocal inhibition in the hyperekplectic patients and explain why voluntary movements are not more severely affected.


Subject(s)
Glycine/metabolism , Leg/innervation , Motor Neurons/physiology , Nervous System Diseases/physiopathology , Neural Inhibition , Pyramidal Tracts/physiopathology , Synaptic Transmission , Adult , Electric Stimulation , Electromyography , H-Reflex , Humans , Magnetics , Middle Aged , Muscle, Skeletal/physiopathology , Receptors, Glycine/genetics
8.
J Neurol ; 249(6): 651-61, 2002 Jun.
Article in English | MEDLINE | ID: mdl-12111295

ABSTRACT

Neurological and neuromuscular disorders are frequent complications in patients with neoplasms and may involve the neuromuscular system, including motor and sensory nerve cell bodies, axons, myelin, neuromuscular transmission and muscle alone or in combination. Electrophysiological studies are of value in delineating the type, degree and extent of involvement, and may be of assistance in pointing towards the underlying cause: paraneoplastic factors, treatment with chemotherapy or radiation or metastatic infiltration. Though some electrophysiological features may be characteristic of certain syndromes, they rarely can stand alone but require clinical, pathological, radiological, and laboratory studies to obtain a diagnosis. Even in cases where such studies are obtained, a final diagnosis may only be ascertained during follow up, since the neuromuscular disorders frequently occur before the neoplasm is detected.


Subject(s)
Central Nervous System Diseases/etiology , Meningeal Neoplasms/secondary , Neoplasm Metastasis/physiopathology , Neoplasms/complications , Paraneoplastic Polyneuropathy/physiopathology , Animals , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Brachial Plexus Neuropathies/etiology , Brachial Plexus Neuropathies/pathology , Brachial Plexus Neuropathies/physiopathology , Central Nervous System Diseases/physiopathology , Humans , Lumbosacral Plexus/drug effects , Lumbosacral Plexus/physiopathology , Lumbosacral Plexus/radiation effects , Neoplasms/physiopathology , Neural Conduction/physiology , Radiotherapy/adverse effects
9.
J Subst Abuse Treat ; 21(2): 67-75, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11551735

ABSTRACT

This article examines a comprehensive, residential substance abuse treatment program for women and their children. A majority of the 72 participants studied were African American single mothers, for whom crack/cocaine was the drug of choice. The women and their children were assessed repeatedly during treatment, and at 3, 6, and 12 months postdischarge. Program impact was estimated by comparing the outcomes of three groups that differed in the amount of treatment they received: early dropouts, late dropouts, and treatment graduates. Program graduates showed more positive outcomes than the nongraduate comparison groups in the areas of drug use and negative consequences of use, employment and self-sufficiency, and family interaction skills. Young children enrolled in treatment with their mothers were assessed using a developmental screening test, and older children with a measure of drug refusal skills. Results from both child measures suggest substantial improvement.


Subject(s)
Residential Treatment , Substance Abuse Treatment Centers , Substance-Related Disorders/therapy , Adolescent , Adult , Analysis of Variance , Arkansas , Child , Child, Preschool , Early Intervention, Educational , Female , Humans , Infant , Infant, Newborn , Male , Treatment Outcome
10.
Psychosomatics ; 42(4): 285-99, 2001.
Article in English | MEDLINE | ID: mdl-11496018

ABSTRACT

The continuing popularity of complementary medicine has led to the frequent appearance of new products in the marketplace. Non-herbal supplements are now a popular choice for patients seeking relief from a variety of medical conditions. As with herbal medicines, there are concerns about the safety of these products in those with physical illness. Clearly, consultation-liaison psychiatrists will encounter patients using non-herbal products or inquiring about them. This article seeks to provide knowledge about the risks and benefits of non-herbal supplements that consultation-liaison psychiatrists are likely to encounter.


Subject(s)
Dietary Supplements/adverse effects , Patient Care Team , Psychophysiologic Disorders/drug therapy , Psychoses, Substance-Induced/etiology , Referral and Consultation , Self Medication/psychology , Somatoform Disorders/drug therapy , Clinical Trials as Topic , Drug Interactions , Humans , Psychiatry , Psychophysiologic Disorders/psychology , Somatoform Disorders/psychology
12.
Exp Brain Res ; 140(2): 190-7, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11521151

ABSTRACT

The aim of the present study was to investigate the contribution of reciprocal inhibition to muscle tone by examining the transmission in the reciprocal inhibitory pathway in patients with a known defect in the glycine receptor. The study was performed in eight patients with hereditary hyperekplexia, six with the major form and two with the minor form of the disease. A mutation in the alpha1-subunit of the glycine receptor had been demonstrated in the patients with the major form, whereas no mutation was seen in the patients with the minor form. Disynaptic reciprocal inhibition, which is presumed to be mediated by glycine, was not seen in the patients with the major form of the disease, while it could be evoked in the patients with the minor form of the disease. Presynaptic inhibition, which is presumed to be mediated by GABA, was seen in both types of patients. It is concluded that the major form of hereditary hyperekplexia is associated with impaired transmission in glycinergic reciprocal inhibitory pathways. The findings demonstrate the importance of reciprocal inhibition for the muscle tone in man, and it is suggested that the impaired reciprocal inhibition seen in patients with a defect in the glycine receptor may contribute to the increased muscle stiffness that is observed in these patients.


Subject(s)
Ankle Joint/physiopathology , Movement Disorders/physiopathology , Muscle, Skeletal/physiopathology , Neural Inhibition/physiology , Neuromuscular Diseases/physiopathology , Adult , Electromyography , Glycine/physiology , H-Reflex/physiology , Humans , Middle Aged , Muscle Hypertonia/physiopathology , Muscle, Skeletal/innervation , Reflex, Startle/physiology , Synapses/physiology , Tendons/physiology
13.
FEBS Lett ; 500(3): 157-62, 2001 Jul 06.
Article in English | MEDLINE | ID: mdl-11445077

ABSTRACT

Tangier disease (TD) is an inherited disorder of lipid metabolism characterized by very low high density lipoprotein (HDL) plasma levels, cellular cholesteryl ester accumulation and reduced cholesterol excretion in response to HDL apolipoproteins. Molecular defects in the ATP binding cassette transporter 1 (ABCA1) have recently been identified as the cause of TD. ABCA1 plays a key role in the translocation of cholesterol across the plasma membrane, and defective ABCA1 causes cholesterol storage in TD cells. Not only cholesterol efflux, but also phospholipid efflux was shown to be impaired in TD cells. By use of thin layer chromatography, high performance liquid chromatography and time-of-flight secondary ion mass spectrometry, we characterized the cellular phospholipid content in fibroblasts from three homozygous TD patients. The cellular content of the major phospholipids was not found to be significantly altered in TD fibroblasts. However, the two phospholipids cardiolipin and lysocardiolipin, which make up minute amounts in normal cells, were at least 3-5-fold enriched in fibroblasts from TD subjects. A structurally closely related phospholipid (lysobisphosphatidic acid) has recently been shown to be enriched in Niemann-Pick type C, another lipid storage disorder. Altogether these data may indicate that the role of these phospholipids is a regulatory one rather than that of a bulk mediator of cholesterol solubilization in sterol trafficking and efflux.


Subject(s)
Cardiolipins/metabolism , Fibroblasts/metabolism , Tangier Disease/metabolism , ATP Binding Cassette Transporter 1 , ATP-Binding Cassette Transporters/genetics , Adult , Aged , Biological Transport , Cardiolipins/analysis , Cells, Cultured , Cholesterol/metabolism , Chromatography, High Pressure Liquid , Chromatography, Thin Layer , Female , Fibroblasts/chemistry , Fibroblasts/pathology , Homozygote , Humans , Male , Middle Aged , Phospholipids/analysis , Phospholipids/metabolism , Sensitivity and Specificity , Spectrometry, Mass, Secondary Ion , Tangier Disease/genetics , Tangier Disease/pathology
14.
Brain ; 124(Pt 4): 826-37, 2001 Apr.
Article in English | MEDLINE | ID: mdl-11287381

ABSTRACT

The aim of the study was to investigate whether impaired control of transmission in spinal inhibitory pathways contributes to the functional disability of patients with spasticity. To this end, transmission in the pathways mediating disynaptic reciprocal Ia inhibition and presynaptic inhibition was investigated in 23 healthy subjects and 20 patients with spastic multiple sclerosis during ankle dorsiflexion and plantar flexion. In healthy subjects, but not in spastic patients, the soleus H reflex was depressed at the onset of dorsiflexion (300 ms rise time, 20% of maximal voluntary effort). At the onset of plantar flexion, the soleus H reflex was more facilitated in the healthy subjects than in the patients. The H reflex increased more with increasing level of tonic plantar flexion and decreased more with dorsiflexion in the healthy subjects than in the spastic patients. Transmission in the disynaptic Ia reciprocal inhibitory pathway from ankle dorsiflexors to plantar flexors was investigated by conditioning the soleus H reflex by previous stimulation of the common peroneal nerve (conditioning-test interval 2-3 ms; stimulation intensity 1.05 times the motor response threshold). At the onset of dorsiflexion, stimulation of the common peroneal nerve evoked a significantly larger inhibition than at rest in the healthy subjects but not in the spastic patients. At the onset of plantar flexion the inhibition decreased in the healthy subjects, but because only weak inhibition was observed at rest in the patients it was not possible to determine whether a similar decrease occurred in this group. There were no differences in the modulation of inhibition during tonic plantar flexion and dorsiflexion in the two populations. Presynaptic inhibition of Ia afferents terminating on soleus motor neurones was evaluated from the monosynaptic Ia facilitation of the soleus H reflex evoked by femoral nerve stimulation. Femoral nerve facilitation was decreased at the onset of dorsiflexion and increased at the onset of plantar flexion in the healthy subjects and patients, but the changes were significantly greater in the healthy subjects. There was no difference between the two populations in the modulation of presynaptic inhibition during tonic plantar flexion and dorsiflexion. It is suggested that the abnormal regulation of disynaptic reciprocal inhibition and presynaptic inhibition in patients with spasticity is responsible for the abnormal modulation of stretch reflexes in relation to voluntary movement in these patients. Lack of an increase in reciprocal inhibition and presynaptic inhibition at the onset of dorsiflexion may be responsible for the tendency to elicitation of unwanted stretch reflex activity and co-contraction of antagonistic muscles in patients with spasticity.


Subject(s)
Multiple Sclerosis/physiopathology , Muscle Contraction , Muscle Spasticity/physiopathology , Neural Inhibition , Presynaptic Terminals , Adult , Afferent Pathways/physiopathology , Electric Stimulation , Femoral Nerve/physiopathology , Foot , H-Reflex , Humans , Middle Aged , Movement/physiology , Multiple Sclerosis/complications , Muscle Contraction/physiology , Muscle Spasticity/etiology , Muscle, Skeletal/innervation , Muscle, Skeletal/physiopathology , Peroneal Nerve/physiopathology , Spinal Cord/physiopathology , Synaptic Transmission
15.
Clin Neurophysiol ; 111(8): 1372-9, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10904217

ABSTRACT

OBJECTIVES: To measure the effect of baclofen on the transmission in different spinal pathways to soleus motoneurones in spastic multiple sclerosis patients. METHODS: Baclofen was administered orally in 14 and intrathecally in 8 patients. H(max)/M(max), presynaptic inhibition by biceps femoris tendon tap of femoral nerve stimulation, depression of the soleus H-reflex following previous activation of the Ia afferents from the soleus muscle (i.e. postactivation depression), disynaptic reciprocal Ia inhibition of the soleus H-reflex and the number of backpropagating action potentials in primary afferents, which may be a sign of presynaptic inhibition, were examined. RESULTS: Baclofen depressed the soleus H(max)/M(max) ratio significantly following oral and intrathecal baclofen. None of the two tests of presynaptic inhibition, or the postactivation depression or the disynaptic reciprocal Ia inhibition of the soleus H-reflex were affected by baclofen administration. Also the action potentials of the primary afferents were unchanged during baclofen administration. CONCLUSIONS: The antispastic effect of baclofen is not caused by an effect on the transmitter release from Ia afferents or on disynaptic reciprocal Ia inhibition. One possible explanation of the depression of the H-reflex by baclofen is suggested to be a direct depression of motoneuronal excitability.


Subject(s)
Baclofen/administration & dosage , Multiple Sclerosis/drug therapy , Multiple Sclerosis/physiopathology , Neural Pathways/drug effects , Neural Pathways/physiopathology , Spasm/drug therapy , Spasm/physiopathology , Spinal Cord/drug effects , Spinal Cord/physiopathology , Administration, Oral , Adult , Electric Stimulation , Electromyography , Female , H-Reflex/drug effects , H-Reflex/physiology , Humans , Injections, Spinal , Male , Middle Aged
19.
Muscle Nerve ; 22(12): 1731-7, 1999 Dec.
Article in English | MEDLINE | ID: mdl-10567091

ABSTRACT

A long-term paraplegic man presented exclusively (>99%) myosin heavy chain I (MHC I) in the tibialis anterior muscle (TA). This was coupled to a slow speed of contraction, a high resistance to fatigue, and a rapid resynthesis of phosphocreatine after an electrically evoked fatiguing contraction when compared with the TA muscles of 9 other paraplegic individuals. In contrast, the MHC composition of his vastus lateralis, gastrocnemius, and soleus muscles was that expected of a muscle from a spinal cord injured individual. This information may be of clinical importance in terms of the expected morphological and functional adaptations of skeletal muscle to different types of electrical stimulation therapy.


Subject(s)
Muscle, Skeletal/metabolism , Myosin Heavy Chains/biosynthesis , Paraplegia/metabolism , Electromyography , Humans , Immunohistochemistry , Magnetic Resonance Spectroscopy , Male , Middle Aged , Muscle Contraction/physiology , Muscle, Skeletal/pathology , Muscle, Skeletal/physiopathology , Paraplegia/pathology , Paraplegia/physiopathology , Protein Isoforms/biosynthesis , Spinal Cord Injuries/metabolism , Tibia
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