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1.
Physiotherapy ; 109: 111-120, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-31493863

RESUMEN

OBJECTIVES: This study aimed to establish and compare current physiotherapy management of GTPS in Australia, New Zealand (NZ) and Ireland. DESIGN: Cross-sectional observational survey of physiotherapists. METHODS: An online survey was distributed to registered musculoskeletal physiotherapists in Australia, NZ and Ireland. Ordinal and nominal data were analysed using frequency counts or mean ranks; median and interquartile ranges were calculated for numerical data. Inter-country comparisons were made using Chi-squared analyses for nominal/ordinal data and Kruskal-Wallis tests for numerical data. Statistical significance was set at P<0.05. RESULTS/FINDINGS: Valid responses were received from 361 physiotherapists, 61% were female and 80% worked in private practice. Overall, consistency in treatment of GTPS was observed across the three countries. All physiotherapists used education and exercise (most commonly strengthening and neuromuscular control) primarily targeting the gluteal muscles. Other interventions included massage (90%), stretching (53%), range of motion (40%), thermal modalities (50%), taping (38%) and electrotherapy (25%), whilst 40% commonly recommended up to 2 to 3 corticosteroid injections per patient/per annum. Physiotherapists used pain severity scales as their primary outcome measure (79%). Single leg stance was the most common physical measure used (68%), and global rating scores or standardised physical measures were less commonly used. CONCLUSION: This international survey established the physiotherapy management of GTPS. Education used in conjunction with exercise is in line with current evidence, but a proportion of clinicians use adjunct treatments without clear rationale or supporting evidence. Results indicate the need to further define optimal management of GTPS using robust methodologies such as randomised controlled trials.


Asunto(s)
Bursitis/terapia , Fémur , Manejo del Dolor/métodos , Modalidades de Fisioterapia , Tendinopatía/terapia , Adulto , Australia , Estudios Transversales , Femenino , Humanos , Irlanda , Masculino , Persona de Mediana Edad , Nueva Zelanda , Dimensión del Dolor , Encuestas y Cuestionarios
2.
Musculoskelet Sci Pract ; 43: 122-126, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31285186

RESUMEN

PURPOSE: To evaluate how physiotherapists across three countries (Australia, New Zealand (NZ) and Ireland) diagnose greater trochanteric pain syndrome (GTPS) using clinical tests and imaging findings, and how physiotherapists update their knowledge regarding GTPS. DESIGN: Cross-sectional observational study of physiotherapists. METHODS: An online survey was distributed to registered physiotherapists in Australia, NZ and Ireland. Ordinal and nominal data were analysed using frequency counts or mean ranks; medians and interquartile ranges were calculated for numerical data. Comparisons between the three countries were made using Chi-squared analyses for nominal/ordinal data and Kruskal Wallis tests for numerical data. Statistical significance was set at p < 0.05. RESULTS/FINDINGS: Valid responses were received from 361 physiotherapists; 61% were female and 79.8% worked in private practice. Most respondents were very confident in diagnosing GTPS (67.9%) and incorporated a range of symptoms and tests, including validated tests, in their diagnosis. However, many physiotherapists were not commonly using some available validated diagnostic tests (e.g. FABER and FADER-R). Approximately 30% of physiotherapists used imaging to inform assessment, with ultrasound being most preferred. Physiotherapists rated hands-on experience as most valuable for updating their knowledge of GTPS, followed by courses. CONCLUSION: While most clinicians appear to be using current evidence in their assessment of patients with GTPS, a proportion use suboptimal methods and/or a limited range of diagnostic tests, suggesting that despite their confidence in diagnosis, further knowledge translation may be required. Future research should determine the best methods of facilitating knowledge acquisition and translation of research into practice.


Asunto(s)
Bursitis/diagnóstico , Bursitis/rehabilitación , Fémur , Conocimientos, Actitudes y Práctica en Salud , Fisioterapeutas , Modalidades de Fisioterapia , Tendinopatía/diagnóstico , Tendinopatía/rehabilitación , Adulto , Australia , Estudios Transversales , Femenino , Humanos , Irlanda , Masculino , Nueva Zelanda , Manejo del Dolor , Dimensión del Dolor , Encuestas y Cuestionarios , Síndrome , Investigación Biomédica Traslacional
3.
Clin Anat ; 29(6): 738-45, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27012306

RESUMEN

Hamstring strains, particularly involving the long head of biceps femoris (BFlh) at the proximal musculotendinous junction (MTJ), are commonly experienced by athletes. With the use of diagnostic ultrasound increasing, an in-depth knowledge of normal ultrasonographic anatomy is fundamental to better understanding hamstring strain. The aim of this study was to describe the architecture of BFlh, using ultrasonography, in young men and cadaver specimens. BFlh morphology was examined in 19 healthy male participants (mean age 21.6 years) using ultrasound. Muscle, tendon and MTJ lengths were recorded and architectural parameters assessed at four standardised points along the muscle. Measurement accuracy was validated by ultrasound and dissection of BFlh in six male cadaver lower limbs (mean age 76 years). Intra-rater reliability of architectural parameters was examined for repeat scans, image analysis and dissection measurements. Distally the BFlh muscle had significantly (P < 0.05) shorter fascicles and larger pennation angles than proximal sites. Agreement between ultrasound and dissection (cadaver study) was excellent for all architectural parameters, except pennation angle (PA), and MTJ length. All other measures demonstrated good-excellent repeatability. BFlh is not uniform in architecture when imaged using ultrasound. It is likely that its distal-most segment is better suited for force production in comparison to the more proximal segments, which show excursive potential, traits which possibly contribute to the high rate of injury at the proximal MTJ. The data presented in this study provide specific knowledge of the normal ultrasonographic anatomy of BFlh, which should be of assistance in analysing BFlh injury via imaging. Clin. Anat. 29:738-745, 2016. © 2016 Wiley Periodicals, Inc.


Asunto(s)
Músculos Isquiosurales/diagnóstico por imagen , Ultrasonografía , Adolescente , Adulto , Músculos Isquiosurales/anatomía & histología , Voluntarios Sanos , Humanos , Masculino , Variaciones Dependientes del Observador , Valores de Referencia , Adulto Joven
4.
Scand J Med Sci Sports ; 26(12): 1480-1489, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26681553

RESUMEN

The proximal musculo-tendinous junction (MTJ) is a common site of hamstring strain injury but the anatomy of this region is not well defined. A morphometric analysis of the proximal MTJs of biceps femoris long head (BFlh), semitendinosus (ST), and semimembranosus (SM) was undertaken from dissection of 10 thighs from five male cadavers and magnetic resonance imaging of 20 thighs of 10 active young men. The length, volume, and cross-sectional area of the proximal tendon, MTJ and muscle belly, and muscle-tendon interface area were calculated. In both groups, MTJs were reconstructed three-dimensionally. The proximal tendons and MTJs were expansive, particularly within SM and BFlh. Morphology varied between muscles although length measurements within individual muscles were similar in cadavers and young men. Semimembranosus had the longest proximal tendon (cadavers: mean 33.6 ± 2.0 cm; young men: mean 31.7 ± 1.6 cm) and MTJ (>20 cm in both groups) and the greatest muscle-tendon interface area, followed by BFlh and ST. Mean muscle belly volumes were more than three times greater in young men than elderly male cadavers (P < 0.001). These unique morphometric data contribute to a better understanding of hamstring anatomy, an important factor in the pathogenesis of hamstring strain injury.


Asunto(s)
Músculos Isquiosurales/diagnóstico por imagen , Tendones Isquiotibiales/diagnóstico por imagen , Adulto , Anciano , Cadáver , Músculos Isquiosurales/anatomía & histología , Tendones Isquiotibiales/anatomía & histología , Humanos , Imagen por Resonancia Magnética , Masculino , Tamaño de los Órganos , Adulto Joven
5.
Clin Anat ; 27(2): 241-53, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23625344

RESUMEN

The anatomy of the hip abductors has not been comprehensively examined, yet is important to understanding function and pathology in the gluteal region. For example, pathology of the hip abductor muscle-tendon complexes can cause greater trochanteric pain syndrome, and may be associated with gluteal atrophy and fatty infiltration. The purpose of this study was to investigate the detailed morphology of gluteus medius (GMed), gluteus minimus (GMin), and tensor fascia lata (TFL), and determine whether the muscles comprised anatomical compartments. The gluteal region from 12 cadavers was dissected and data collected on attachment sites, volume, fascicular and tendinous anatomy, and innervation. Three sites of GMed origin were identified (gluteal fossa, gluteal aponeurosis, and posteroinferior edge of the iliac crest) and the distal tendon had lateral and posterior parts. GMed was the largest in volume (27.6 ± 11.6 cm(3); GMin 14.1 ± 11.1 cm(3); TFL 1.8 ± 0.8 cm(3)). Fascicles of GMin originated from the gluteal fossa, inserting onto the deep surface of its distal tendon and the hip joint capsule. TFL was encapsulated in the fascia lata, having no bony attachment. Primary innervation patterns varied for GMed, with three or four branches supplying different regions of muscle. Distinct secondary nerve branches entered four regions of GMin; no differential innervation was observed for TFL. On the basis of architectural parameters and innervation, GMed, and GMin each comprise of four compartments but TFL is a homogenous muscle. It is anticipated that these data will be useful for future clinical and functional studies of the hip abductors.


Asunto(s)
Cadera/anatomía & histología , Músculo Esquelético/anatomía & histología , Anciano , Anciano de 80 o más Años , Cadáver , Fascia/anatomía & histología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tendones/anatomía & histología
6.
Surg Radiol Anat ; 34(9): 847-55, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22526168

RESUMEN

UNLABELLED: Pathology of the hip abductor muscles and their associated tendons is implicated in the aetiology of lateral hip pain (LHP). Muscle atrophy is an important factor to consider in the diagnosis of this condition as it could result in reduced muscle volume and associated decreases in strength. PURPOSE: (1) To estimate the volumes of the gluteus medius (GMed), gluteus minimus (GMin) and tensor fascia lata (TFL) muscles, and (2) to examine pathological changes of the soft tissues in the vicinity of the hip joint, in women with and without LHP. METHODS: Twenty female participants (10 with LHP and 10 age-matched controls) underwent magnetic resonance imaging. Two radiologists reviewed the images for signs of pathological changes. Hip abductor muscle volumes were estimated using cross-sectional areas and Cavalieri's method. Differences in volume between sides, study groups and the three muscles were assessed. RESULTS: The volume of GMed was the largest (292.5 ± 33.3 cm3), followed by GMin (82.1 ± 12.1 cm3), then TFL (49.7 ± 18.9 cm3). No differences were evident in the volumes of the hip abductor muscles in individuals with LHP when compared to age- and sex-matched controls (GMed, p = 0.30; GMin, p = 0.40; TFL, p = 0.90). Pathology of the soft tissues was not specific to the symptomatic hips. CONCLUSIONS: Novel muscle volume data are presented for GMed, GMin and TFL in the context of LHP. Further research is needed to determine if symptom severity and duration have an impact on the extent of muscle atrophy in this population.


Asunto(s)
Articulación de la Cadera/patología , Imagen por Resonancia Magnética/métodos , Músculo Esquelético/patología , Atrofia Muscular/diagnóstico , Dolor/patología , Adulto , Anciano , Estudios de Casos y Controles , Femenino , Humanos , Persona de Mediana Edad , Variaciones Dependientes del Observador , Tamaño de los Órganos , Dolor/etiología
7.
Br J Sports Med ; 46(12): 871-6, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22006933

RESUMEN

OBJECTIVE: The adductor muscles are implicated in the pathogenesis of groin strain, but the proximal morphology of this muscle group is poorly defined. The purpose of this study was to investigate the detailed anatomy of the entheses and proximal musculotendinous junctions (MTJs) of adductor longus (AL), adductor brevis (AB) and gracilis. METHODS: The adductors were dissected bilaterally in 10 embalmed cadavers (7 females, mean age at death 79 years (range 57-93 years)), focusing on the type of enthesis, and architecture of the proximal tendons and MTJs. Histology was used to determine if the entheses contained fibrocartilage and to semiquantitatively assess the vascularity of each proximal tendon. RESULTS: All entheses were fibrocartilaginous. The proximal tendons of AB and gracilis were fused, forming a common tendinous insertion in all specimens. AL and AB both contained extensive intramuscular tendons of variable length (AL 11.1 ± 1.5 cm; AB 5.4 ± 1.1 cm); this has not been recorded previously. The vascularity of AL and AB tendons decreased significantly towards the enthesis (p < 0.05), and their entheses were significantly less vascular than that of gracilis (p < 0.05). CONCLUSIONS: The proximal anatomy of AL, AB and gracilis is more complex than previously described. The arrangement and fusion of these muscles, their fibrocartilaginous entheses and differences in vascularity of their proximal tendons may be important anatomical considerations in the pathogenesis and pattern of adductor-related groin pain.


Asunto(s)
Músculo Esquelético/anatomía & histología , Tendones/anatomía & histología , Anciano , Anciano de 80 o más Años , Cadáver , Femenino , Fibrocartílago/anatomía & histología , Humanos , Masculino , Persona de Mediana Edad , Músculo Esquelético/irrigación sanguínea , Tendones/irrigación sanguínea , Muslo
8.
Clin Anat ; 23(5): 575-85, 2010 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-20309954

RESUMEN

Anterior knee pain or patellofemoral pain syndrome is commonly encountered by clinicians, but the pathogenesis of this condition is not well understood. While much research has centred around the relationship between vastus medialis and anterior knee pain, little is known about the most lateral of the quadriceps muscle group, vastus lateralis (VL). Knowledge of the anatomical organization of VL is not only necessary to understand its precise function, but to also assist in the development of clinical and biomechanical models of knee dysfunction. The purpose of this study was to investigate the detailed morphology of VL, specifically to provide data relating to architecture, attachment sites, innervation, and the presence of anatomical partitioning within the muscle. The VL muscle was examined in 10 cadaveric lower limbs using macrodissection techniques. On the basis of architecture and innervation, this muscle comprised four partitions with each receiving its own unique nerve branch. The mean fascicular length of VL was 7 cm and the mean fascicular and muscle physiological cross-sectional areas were 1.2 cm(2) and 21.6 cm(2), respectively. In addition to inserting proximally at the base of the greater trochanter and distally into the superolateral border and base of the patella, three additional attachment sites were identified: the lateral intermuscular septum, iliotibial band, and the rectus tendon. The results of this study suggest that the gross morphology of VL is more complex than previously described, and the information provided regarding architecture will contribute to knowledge regarding the function of VL as well as its role in knee joint dysfunction.


Asunto(s)
Rodilla/anatomía & histología , Músculo Cuádriceps/anatomía & histología , Anciano , Anciano de 80 o más Años , Cadáver , Femenino , Humanos , Rodilla/inervación , Rodilla/fisiología , Pierna/anatomía & histología , Pierna/inervación , Masculino , Músculo Cuádriceps/inervación , Músculo Cuádriceps/fisiología
10.
Neuropsychology ; 13(2): 171-87, 1999 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10353369

RESUMEN

Twelve neurologically normal participants (4 men and 8 women) performed semantic, phonological, and orthographic working memory tasks and a control task during functional magnetic resonance imaging. Divergent regions of the posterior left hemisphere used for decoding and storage of information emerged in each working memory versus control task comparison. These regions were consistent with previous literature on processing mechanisms for semantic, phonological, and orthographic information. Further, working memory versus control task differences extended into the left frontal lobe, including premotor cortex, and even into subcortical structures. Findings were consistent with R. C. Martin and C. Romani's (1994) contention that different forms of verbal working memory exist and further suggest that a reconceptualization of premotor cortex functions is needed.


Asunto(s)
Mapeo Encefálico/métodos , Lóbulo Frontal/anatomía & histología , Imagen por Resonancia Magnética/métodos , Memoria a Corto Plazo/fisiología , Psicolingüística/métodos , Aprendizaje Verbal/fisiología , Adolescente , Adulto , Dominancia Cerebral/fisiología , Femenino , Lóbulo Frontal/fisiología , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Memoria a Corto Plazo/clasificación , Corteza Prefrontal/anatomía & histología , Corteza Prefrontal/fisiología , Desempeño Psicomotor/fisiología , Valores de Referencia , Pruebas de Asociación de Palabras
11.
J Cogn Neurosci ; 11(2): 135-52, 1999 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10198130

RESUMEN

Whole-brain functional magnetic resonance imaging (MRI) was used to examine the neural substrates of internally (endogenous) and externally (exogenous) induced covert shifts of attention. Thirteen normal subjects performed three orienting conditions: endogenous (location of peripheral target predicted by a central arrow 80% of the time), exogenous (peripheral target preceded by noninformative central cue). Behavioral results indicated faster reaction times (RTs) for valid than for invalid trials for the endogenous condition but slower RTs for valid than for invalid trials for the exogenous condition (inhibition of return). The spatial extent and intensity of activation was greatest for the endogenous condition, consistent with the hypothesis that endogenous orienting is more effortful (less automatic) than exogenous orienting. Overall, we did not observe distinctly separable neural systems associated with the endogenous and exogenous orienting conditions. Both exogenous and endogenous orienting, but not the control condition, activated bilateral parietal and dorsal premotor regions, including the frontal eye fields. These results suggest a specific role for these regions in preparatory responding to peripheral stimuli. The right dorsolateral prefrontal cortex (BA 46) was activated selectively by the endogenous condition. This finding suggests that voluntary, but not reflexive, shifts of attention engage working memory systems.


Asunto(s)
Atención/fisiología , Mapeo Encefálico , Encéfalo/fisiología , Señales (Psicología) , Imagen por Resonancia Magnética , Desempeño Psicomotor/fisiología , Conducta Espacial/fisiología , Vías Visuales/fisiología , Percepción Visual/fisiología , Adulto , Dominancia Cerebral , Femenino , Fijación Ocular , Lóbulo Frontal/fisiología , Giro del Cíngulo/fisiología , Humanos , Masculino , Modelos Neurológicos , Modelos Psicológicos , Lóbulo Parietal/fisiología , Estimulación Luminosa , Corteza Prefrontal/fisiología , Tiempo de Reacción , Percepción Espacial/fisiología , Lóbulo Temporal/fisiología , Tálamo/fisiología , Vías Visuales/anatomía & histología
12.
Neuroreport ; 8(8): 1987-93, 1997 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-9223090

RESUMEN

Lesions involving the dorsolateral prefrontal lobes may produce deficits on conceptual reasoning (CR) tasks in humans. Such deficits can also occur with subcortical lesions involving the basal ganglia, thalamus, or cerebellum, suggesting a common, yet widespread, neural network supporting this executive function. Here we report the results of a whole brain functional magnetic resonance imaging (fMRI) experiment in healthy volunteers while performing a CR task. Compared to a sensorimotor control condition, the CR task resulted in discrete subcortical activation sites primarily involving the right basal ganglia, right thalamus and left lateral cerebellum. Cortical activation was present in multiple systems, including the dorsolateral prefrontal and inferior frontal/insular areas; posterior parietal, superior extrastriate, and premotor areas; inferior extrastriate and middle temporal regions; and midline pre-supplementary motor and anterior cingulate regions. Our findings provide strong evidence that CR is mediated by interacting neural systems involving the cerebral cortex, basal ganglia, thalamus, and cerebellum.


Asunto(s)
Encéfalo/fisiología , Formación de Concepto/fisiología , Adulto , Ganglios Basales/fisiología , Cerebelo/fisiología , Discriminación en Psicología/fisiología , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Tálamo/fisiología
13.
Anesthesiology ; 75(3): 489-98, 1991 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-1716080

RESUMEN

Analgesia is an important component of general anesthesia. alpha 2-adrenoceptor agonists such as clonidine and dexmedetomidine are effective analgesics at the spinal level, and furthermore, they reduce the volatile anesthetic requirement. In order to probe a possible spinal-level contribution to general anesthetic-induced analgesia, the effects of dexmedetomidine were tested in an isolated spinal cord preparation. The effects of dexmedetomidine were compared with those of isoflurane, and dexmedetomidine-isoflurane interactions were explored. The test response was a nociceptive-related slow ventral root potential (slow VRP) recorded from the isolated neonatal rat spinal cord in response to electrical stimulation of a dorsal root. At 0.2-1.28 vol%, isoflurane reversibly depressed the slow VRP. At a lower concentration (0.14 vol%), isoflurane increased the slow VRP in three of five preparations. At 1.0-1.28 vol%, isoflurane also depressed the monosynaptic reflex. Recovery on washout usually was to a level greater than control. The N-methyl-D-aspartate (NMDA) receptor antagonist (DL)-2-amino 5-phosphonovalerate (10 microM) prevented the rebound to levels above control on isoflurane washout. The earlier components of the slow VRP were more sensitive to isoflurane than were the later. Dexmedetomidine (0.5-10 nM) depressed the slow VRP and had no effect on the monosynaptic reflex. The slow VRP depends on both substance P and glutamate NMDA-receptor-mediated neurotransmission; isoflurance and dexmedetomidine depressed responses to both substance P and NMDA. Although the two agents depress responses to the same neurotransmitters, there is no evidence that they act at the same cellular site(s). There was no significant interaction between dexmedetomidine and isoflurane. The results suggest that isoflurane exerts marked inhibitory effects on spinal neurotransmission, depressing both substance P and glutamate-mediated pathways. There is a possible biphasic effect on the NMDA receptor. To the extent that nociception depends on these neurotransmitters, isoflurane may be expected to exert profound analgesic effects at the spinal level. By blocking responses to strongly arousing stimuli, these effects may contribute to general anesthesia. Suppression of nociceptive neurotransmission at the spinal level may contribute to dexmedetomidine's anesthetic-sparing properties as well as to analgesia by this agent.


Asunto(s)
Agonistas alfa-Adrenérgicos/farmacología , Imidazoles/farmacología , Isoflurano/farmacología , Nociceptores/efectos de los fármacos , Médula Espinal/efectos de los fármacos , Analgésicos , Anestesia General , Animales , Animales Recién Nacidos , Interacciones Farmacológicas , Estimulación Eléctrica , Técnicas In Vitro , Medetomidina , N-Metilaspartato/farmacología , Ratas , Ratas Endogámicas , Reflejo Monosináptico/efectos de los fármacos , Sustancia P/farmacología , Transmisión Sináptica
14.
Brain Res ; 559(1): 17-21, 1991 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-1723644

RESUMEN

Substance P and glutamate actions have separately been implicated in the generation of nociceptive-related slow ventral root potentials (slow VRPs). We report that slow VRPs are dependent on both substance P and NMDA receptor-mediated neurotransmission. Slow VRPs of 10-40 s duration were evoked by electrically stimulating a lumbar dorsal root and recorded at the corresponding ipsilateral ventral root in spinal cords isolated from 1- to 5-day-old rats; the monosynaptic reflex was also recorded. The NMDA receptor antagonist APV (5-20 microM) and the substance P antagonist spantide (10-20 microM) both reversibly depressed the slow VRP without affecting the monosynaptic reflex; spantide and APV applied together nearly abolished the slow VRP. The quisqualate-kainate receptor antagonist CNQX (1-5 microM) reduced the monosynaptic reflex and an early component of the slow VRP. A slow VRP could be elicited by brief (0.1-1.0 s) focal applications of either substance P (2-20 microM) or NMDA (10 microM), and also by CGRP (2-20 microM). Substance P-evoked and NMDA-evoked responses were blocked by their respective antagonists spantide and APV. Each was also cross-sensitive to the other antagonist. Both excitatory amino acids, acting on an NMDA receptor, and substance P, acting on a tachykinin receptor, thus appear to be involved in generating this slow potential. Both NMDA and tachykinin receptors are necessary to generate a full response.


Asunto(s)
Animales Recién Nacidos/fisiología , Nociceptores/efectos de los fármacos , Receptores de N-Metil-D-Aspartato/efectos de los fármacos , Raíces Nerviosas Espinales/fisiología , Sustancia P/fisiología , 2-Amino-5-fosfonovalerato/farmacología , 6-Ciano 7-nitroquinoxalina 2,3-diona , Aminoácidos/fisiología , Animales , Ácido Kaínico/farmacología , Potenciales de la Membrana/efectos de los fármacos , Nociceptores/fisiología , Quinoxalinas/farmacología , Ratas , Ratas Endogámicas , Receptores de N-Metil-D-Aspartato/fisiología , Reflejo Monosináptico/efectos de los fármacos , Raíces Nerviosas Espinales/efectos de los fármacos , Transmisión Sináptica/efectos de los fármacos
16.
Eur J Pharmacol ; 192(2): 293-300, 1991 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-1674474

RESUMEN

Alpha 2-Adrenoceptors mediate analgesia in vivo. The present study explored the actions of the alpha 2-adrenoceptor agonists dexmedetomidine and clonidine on a nociceptive response in isolated neonatal rat spinal cord. Stimulation of a dorsal root generates a slow ventral root potential (slow VRP) at the corresponding ipsilateral ventral root. The slow VRP meets several criteria for a nociceptive response. Dexmedetomidine (10 nM) and clonidine (200 nM) depressed the slow VRP by approximately 80%. Dexmedetomidine's action was approximately linear over the concentration range 0.5-500 nM, whereas clonidine (20 nM-5 microM) exerted biphasic effects. The profile of agonist and antagonist effectiveness characterized the receptor(s) as alpha 2-adrenoceptors; the subtype could not be identified as either alpha 2A or alpha 2B. Naloxone pretreatment partially blocked dexmedetomidine's effect, suggesting a possible endogenous opiate involvement. Dexmedetomidine (0.5-2.0 nM) also depressed the VRP evoked by application of substance P to the cord, implicating postsynaptic as well as possible presynaptic actions. At high concentrations, dexmedetomidine (50-500 nM) depressed the monosynaptic reflex, probably through non-alpha 2-receptor(s). Results from the neonatal spinal cord correlate well with those from in vivo analgesia studies. They suggest an important direct spinal contribution to alpha 2-adrenoceptor-mediated analgesia.


Asunto(s)
Agonistas alfa-Adrenérgicos/farmacología , Analgesia , Clonidina/farmacología , Imidazoles/farmacología , Receptores Adrenérgicos alfa/fisiología , Médula Espinal/fisiología , Antagonistas Adrenérgicos alfa/farmacología , Animales , Animales Recién Nacidos , Clonidina/antagonistas & inhibidores , Potenciales Evocados/efectos de los fármacos , Imidazoles/antagonistas & inhibidores , Técnicas In Vitro , Medetomidina , Naloxona/farmacología , Ratas , Ratas Endogámicas , Reflejo Monosináptico/efectos de los fármacos , Médula Espinal/efectos de los fármacos
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