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1.
Clin Exp Immunol ; 143(2): 203-8, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16412043

ABSTRACT

Oral infection by Anisakis simplex third stage larvae (L3) frequently gives rise to an allergic response. To comprehend the allergic and immune responses induced by L3, we investigated the kinetics of specific antibody isotype expression and the time course of biological and immunochemical allergy states using sera prepared from rats orally infected with L3 twice, with an interval of 9 weeks between infections. Biological and immunochemical allergy states were analysed by RBL-2H3 exocytosis and by indirect ELISA for IgE, respectively. The peak IgM at reinfection (RI) was comparable or similar to that at primary infection (PI) both in levels analysed by indirect ELISA and in antigen recognition analysed by Western blot. IgG1 and IgG2a levels were higher and showed accelerated kinetics after RI vs. after PI. However, the level of IgG2b was substantially lower than that of IgG2a. Peak immunochemical and biological allergy states for RI were higher and were reached faster than those for PI. The peak biological allergy state was observed at 1 week postreinfection and this occurred sooner than that for the peak immunochemical allergy state found at 2 weeks postreinfection. Our analysis of the relationship between specific IgE avidity and biological allergy state did not show any meaningful correlation. These results suggest that the allergic response induced by L3 oral infection is predominantly caused by reinfection and that this is accompanied by an elevated IgM level, which further suggests that the biological allergy state might not be related to specific IgE avidity.


Subject(s)
Anisakiasis/immunology , Hypersensitivity/immunology , Animals , Antibody Affinity/immunology , Antigens/immunology , Blotting, Western/methods , Enzyme-Linked Immunosorbent Assay/methods , Exocytosis/immunology , Immunoglobulin E/immunology , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Larva/immunology , Rats , Rats, Sprague-Dawley , Time Factors
2.
Yonsei Med J ; 42(4): 436-9, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11519087

ABSTRACT

Left ventricular rupture is a fatal complication of acute myocardial infarction, however accurate preoperative diagnosis is still difficult. We experienced a postinfarction left ventricular rupture patient whose symptoms and radiologic findings mimicked those of acute intramural hematoma of the aorta. Upon emergency operation, he was proven to have a postinfarction LV rupture and underwent successful surgery. We herein report the case with a brief review of the literature.


Subject(s)
Aortic Diseases/diagnosis , Heart Rupture, Post-Infarction/diagnosis , Hematoma/diagnosis , Diagnostic Errors , Heart Rupture, Post-Infarction/surgery , Humans , Male , Middle Aged
3.
Neurosci Lett ; 308(2): 95-8, 2001 Aug 03.
Article in English | MEDLINE | ID: mdl-11457568

ABSTRACT

Quantification of arthritic pain can be very useful in elucidating the mechanisms of arthritis and in assessing the effect of anti-arthritic medication or treatment. Here we report a novel method that allows convenient measurements of the severity of arthritic pain in voluntarily walking rats. We constructed a device to measure the weight load on each leg while the animal was walking through a path, the bottom of which was equipped with strain gauge weight sensors. Using this device, we measured the weight load on the right hind leg before and after induction of arthritis by carrageenan injection into the knee joint cavity of this leg. The carrageenan injection resulted in a significant reduction of weight load on the affected leg; the load decreased to the minimum level at 4 h after the injection and gradually returned to the pre-injection level by the fifth day. Intraperitoneal administration of morphine at 5.5 h after carrageenan injection could reverse the weight load change. These results suggest that our new device is an effective tool for convenient measurements of arthritic pain in dynamic conditions like walking.


Subject(s)
Arthritis/diagnosis , Gait/physiology , Pain Measurement/methods , Pain/diagnosis , Walking/physiology , Analgesics, Opioid/pharmacology , Animals , Arthritis/chemically induced , Arthritis/physiopathology , Carrageenan/antagonists & inhibitors , Carrageenan/pharmacology , Disability Evaluation , Disease Models, Animal , Gait/drug effects , Knee Joint/drug effects , Knee Joint/pathology , Knee Joint/physiopathology , Male , Morphine/pharmacology , Pain/etiology , Pain/physiopathology , Rats , Rats, Sprague-Dawley , Weight-Bearing/physiology
4.
J Neurosci ; 21(11): 4026-31, 2001 Jun 01.
Article in English | MEDLINE | ID: mdl-11356889

ABSTRACT

Glutamate is considered to be the primary neurotransmitter in the retinohypothalamic tract (RHT), which delivers photic information from the retina to the suprachiasmatic nucleus (SCN), the locus of the mammalian circadian pacemaker. However, substance P (SP) also has been suggested to play a role in retinohypothalamic transmission. In this study, we sought evidence that SP from the RHT contributes to photic resetting of the circadian pacemaker and further explored the possible interaction of SP with glutamate in this process. In rat hypothalamic slices cut parasagittally, electrical stimulation of the optic nerve in early and late subjective night produced a phase delay (2.4 +/- 0.5 hr; mean +/- SEM) and advance (2.6 +/- 0.3 hr) of the circadian rhythm of SCN neuronal firing activity, respectively. The SP antagonist L-703,606 (10 microm) applied to the slices during the nerve stimulation completely blocked the phase shifts. Likewise, a cocktail of NMDA (2-amino-5-phosphonopentanoic acid, 50 microm) and non-NMDA (6,7-dinitroquinoxaline-2,3-dione, 10 microm) antagonists completely blocked the shifts. Exogenous application of SP (1 microm) or glutamate (100 microm) to the slices in early subjective night produced a phase delay ( approximately 3 hr) of the circadian firing activity rhythm of SCN neurons. Coapplication of the NMDA and non-NMDA antagonist cocktail (as well as L-703,606) resulted in a complete blockade of the SP-induced phase delay, whereas L-703,606 (10 microm) had no effect on the glutamate-induced delay. These results suggest that SP, as well as glutamate, has a critical role in photic resetting. Furthermore, the results suggest that the two agonists act in series, SP working upstream of glutamate.


Subject(s)
Biological Clocks/physiology , Circadian Rhythm/physiology , Hypothalamus/metabolism , Photoperiod , Substance P/metabolism , Animals , Biological Clocks/drug effects , Circadian Rhythm/drug effects , Electric Stimulation , Excitatory Amino Acid Antagonists/pharmacology , Glutamic Acid/metabolism , Glutamic Acid/pharmacology , Hypothalamus/drug effects , In Vitro Techniques , Male , Membrane Potentials/drug effects , Membrane Potentials/physiology , Neurons/physiology , Optic Nerve/physiology , Quinuclidines/pharmacology , Rats , Rats, Sprague-Dawley , Substance P/antagonists & inhibitors , Substance P/pharmacology , Suprachiasmatic Nucleus/cytology , Suprachiasmatic Nucleus/drug effects , Suprachiasmatic Nucleus/physiology
5.
Exp Brain Res ; 130(1): 93-9, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10638445

ABSTRACT

The purpose of this study was to measure the changes in levels of nerve growth factor (NGF) in dorsal root ganglia (DRG) and spinal nerves with the aim of investigating the role of NGF in a rat neuropathic pain model. Nerve injuries were made by tight ligation of the left L5 and L6 spinal nerves using 6-0 silk thread in male Sprague-Dawley rats. Before surgery and 1, 3, 5, 7, and 14 days after surgery, tissue samples collected included the L3-6 DRGs bilaterally, segments of the ipsilateral L5-6 spinal nerves proximal and distal to ligation sites, and corresponding sites of the contralateral L3-6 and the ipsilateral L3-4 spinal nerves. NGF levels in the DRGs of the injured spinal nerves (the left L5 and L6) did not change significantly from control values. The spinal nerve segments distal to ligation sites had higher levels of NGF than the control values. Unlesioned sites did not show any significant changes in NGF levels. The increase of NGF in distal segments of injured spinal nerves may be due to an accumulation of retrogradely transported NGF. The maintenance of NGF levels in the DRGs that had lost peripheral connections may reflect local synthesis after nerve injury.


Subject(s)
Ganglia, Spinal/metabolism , Nerve Growth Factors/metabolism , Pain/physiopathology , Peripheral Nervous System Diseases/physiopathology , Spinal Nerves/metabolism , Animals , Disease Models, Animal , Ganglia, Spinal/physiopathology , Male , Rats , Rats, Sprague-Dawley , Spinal Nerves/physiopathology , Time Factors
6.
Exp Brain Res ; 129(2): 167-71, 1999 Nov.
Article in English | MEDLINE | ID: mdl-10591890

ABSTRACT

This study compared and contrasted the manifestation of neuropathic pain behaviors in several strains of rats. These included ACI, Brown-Norway, Fischer 344, Lewis, Long-Evans, Sprague-Dawley, and Wistar-Furth, all obtained from Harlan Sprague-Dawley Inc. Comparison was also made between two substrains of Sprague-Dawley rats: one from Harlan and the other from Sasco. Neuropathic injury was produced by tightly ligating the left L5 and L6 spinal nerves with the animals under halothane anesthesia. Tests were conducted for 2 weeks to examine behavioral signs representing mechanical allodynia, cold allodynia, and spontaneous pain. There was no difference between strains in any of the tested behaviors before surgery. After neuropathic injury, rats in most groups developed high levels of behavioral signs of various components of neuropathic pain; however, some strains of rats showed weak behavioral signs of neuropathic pain. When a comparison was made between two substrains of Sprague-Dawley rats from two different sources, the ones from Sasco showed weaker behavioral signs than those from Harlan. When comparisons were made between different strains of rats from the same source (Harlan), Brown-Norway and Long-Evans rats showed the smallest magnitude of neuropathic pain behaviors. The data indicate that different strains and substrains of rats display different degrees of pain behaviors, suggesting that strains and substrains are important variables in the development of neuropathic pain after peripheral nerve injury.


Subject(s)
Behavior, Animal/physiology , Causalgia/physiopathology , Hyperalgesia/physiopathology , Animals , Peripheral Nerve Injuries , Peripheral Nerves/physiopathology , Rats , Rats, Inbred ACI , Rats, Inbred BN , Rats, Inbred F344 , Rats, Inbred Lew , Rats, Inbred WF , Rats, Long-Evans , Rats, Sprague-Dawley , Species Specificity , Sympathetic Nervous System/physiopathology
7.
Neuroreport ; 10(7): 1493-9, 1999 May 14.
Article in English | MEDLINE | ID: mdl-10380969

ABSTRACT

Numerous studies have suggested that changes in electrophysiological properties of primary sensory neurons after axonal injury contribute to the generation of neuropathic pain. Presently, however, it is unclear which of the changes is important. To address this issue, we performed behavioral and electrophysiological experiments in a double-blind fashion; we made intracellular recordings in the S1 dorsal root ganglia excised from rats exhibiting cold allodynia behavior after chronic S1 spinal nerve transaction (allodynia-positive group) and from rats lacking such behavior after the same nerve injury (allodynia-negative group) or sham injury (sham group). In this study, we sought which of the membrane property changes produced by the spinal nerve injury in each of C-, Adelta- and Aalpha/beta-cell populations was unique to the allodynia-positive group. Analyses of our data revealed that only some changes in Adelta-cells (e.g. the decrease in resting membrane potential and in the threshold of central process) were more pronounced in or unique to the allodynia-positive group. We concluded that certain membrane property changes in the somata and dorsal root axons of Adelta-cells might be important in the generation of cold allodynia.


Subject(s)
Cold Temperature , Ganglia, Spinal/physiopathology , Nerve Fibers/physiology , Neuralgia/physiopathology , Peripheral Nerve Injuries , Action Potentials/physiology , Animals , Axotomy , Behavior, Animal/physiology , Evoked Potentials/physiology , Ganglia, Spinal/pathology , Male , Nerve Fibers/pathology , Neuralgia/etiology , Neuralgia/pathology , Rats , Rats, Sprague-Dawley
8.
Neuroscience ; 86(1): 301-9, 1998 Sep.
Article in English | MEDLINE | ID: mdl-9692763

ABSTRACT

Recent evidence indicates that neuropathic pain from partial peripheral nerve injury is maintained by electrophysiologically abnormal signals from injured sensory neurons. To gain an insight into the mechanisms underlying this electrophysiological abnormality, we examined the effects of S1 spinal nerve transection on the membrane properties of S1 dorsal root ganglion neurons one to two weeks after injury. This injury produced significant action potential broadening [40% (1 ms) in C-, 149% (1.5 ms) in A delta- and 84% (0.5 ms) in A alpha/beta-cells], which was primarily due to the enhancement of the "shoulder" appearing on the falling phase of the action potential in C- and A delta-cells and the emergence of a shoulder in A alpha/beta-cells, and significant cell-type specific changes in the time-course of the rising phase of the action potential; i.e. an increase in rise time (A delta: 35%, 0.15 ms; A alpha/beta: 13%, 0.04 ms) and a decrease in the maximal rate of rise (A delta: 17%, 77 V/s; A alpha/beta: 13%, 79 V/s). In addition, the nerve injury led to a significant reduction of the rheobase, an index of neuronal excitability, in all types of cells (by 41% in C-, 71% in A delta- and 59% in A alpha/beta-cells). The reduction of rheobase in A-cells was associated with a concomitant increase in apparent input resistance (by 269% in A delta- and 192% in A alpha/beta-cells), which was measured near the resting membrane potential. By contrast, the rheobase reduction in C-cells was associated with a concurrent depolarizing shift (approximately 4 mV) of the resting membrane potential. The nerve injury-induced reduction of rheobase was not accompanied by related change in input resistance or threshold potential in any of the cell populations. The present results indicate that chronic peripheral axotomy of dorsal root ganglion neurons, which gives rise to neuropathic pain, produces profound changes in the action potential waveform of dorsal root ganglion neurons in a cell type-specific fashion. Furthermore, the results suggest that the axotomy increases the excitability of dorsal root ganglion neurons not by altering input resistance (i.e. leak conductance) or threshold potential, but by increasing apparent input resistance near the resting membrane potential in A-cells and decreasing the resting membrane potential in C-cells.


Subject(s)
Ganglia, Spinal/physiopathology , Neural Conduction/physiology , Neuralgia/physiopathology , Neurons/physiology , Spinal Nerves/physiopathology , Action Potentials , Animals , Axotomy , Cell Membrane/physiology , Disease Models, Animal , Electric Stimulation , Ganglia, Spinal/physiology , Male , Neurons, Afferent/physiology , Rats , Rats, Sprague-Dawley , Spinal Nerves/physiology
9.
Exp Brain Res ; 120(4): 432-8, 1998 Jun.
Article in English | MEDLINE | ID: mdl-9655228

ABSTRACT

Sympathetic postganglionic fibers sprout in the dorsal root ganglion (DRG) after peripheral nerve injury. Therefore, one possible contributing factor of sympathetic dependency of neuropathic pain is the extent of sympathetic sprouting in the DRG after peripheral nerve injury. The present study compared the extent of sympathetic sprouting in the DRG as well as in the injured peripheral nerve in three rat neuropathic pain models: (1) the chronic constriction injury model (CCI); (2) the partial sciatic nerve ligation injury model (PSI); and (3) the segmental spinal nerve ligation injury model (SSI). All three methods of peripheral nerve injury produced behavioral signs of ongoing and evoked pain with some differences in the magnitude of each pain component. The density of sympathetic fibers in the DRG was significantly higher at all examined postoperative times than controls in the SSI model, while it was somewhat higher than controls only at the last examined postoperative time (20 weeks) in the CCI and PSI models. Therefore, data suggest that, although sympathetic changes in the DRG may contribute to neuropathic pain syndromes in the SSI model, other mechanisms seem to be more important in the CCI and PSI models at early times following peripheral nerve injury.


Subject(s)
Ganglia, Spinal/cytology , Ganglia, Spinal/physiopathology , Nerve Regeneration/physiology , Pain/physiopathology , Animals , Behavior, Animal/physiology , Cold Temperature , Disease Models, Animal , Hyperalgesia/physiopathology , Ligation , Male , Physical Stimulation , Rats , Rats, Sprague-Dawley , Sciatic Nerve/enzymology , Sciatic Nerve/pathology , Sciatic Nerve/surgery , Sympathetic Fibers, Postganglionic/enzymology , Sympathetic Fibers, Postganglionic/pathology , Tyrosine 3-Monooxygenase/analysis
10.
Neurosci Lett ; 246(2): 117-9, 1998 Apr 24.
Article in English | MEDLINE | ID: mdl-9627194

ABSTRACT

This study examined whether or not the production of mechanical allodynia in a rat model of neuropathic pain required an involvement of supraspinal site(s). To this aim, we assessed the effect of spinal cord section at the L1 segment level on the mechanical allodynia sign (i.e. tail flick/twitch response), which was elicited by innocuous von Frey hair stimulation of the tail after unilateral transection of the tail-innervating nerve superior caudal trunk (SCT) at the level between the S3 and S4 spinal nerves. Cord transection or hemisection of the cord ipsilateral to the injured SCT drastically (though not completely) blocked the behavioral sign of mechanical allodynia (leaving noxious pinprick-elicited tail withdrawal reflex intact), whereas sham section or contralateral hemisection of the cord was without effect. These results suggest that the generation of mechanical allodynia following partial peripheral nerve injury involves transmission of the triggering sensory signal to a site(s) rostral to the L1 segment via an ipsilateral pathway(s).


Subject(s)
Pain/physiopathology , Spinal Cord/physiopathology , Spinal Nerves/injuries , Animals , Hair , Male , Rats , Rats, Sprague-Dawley , Reflex , Skin/innervation , Spinal Cord/physiology , Tail/innervation
11.
Yonsei Med J ; 39(2): 166-74, 1998 Apr.
Article in English | MEDLINE | ID: mdl-9587258

ABSTRACT

The objectives of this investigation were to evaluate biomechanical factors in the atherosclerotic process using human in vivo hemodynamic parameters and computed numerical simulation qualitatively and quantitatively. The three-dimensional spatial patterns of steady and pulsatile flows in the left coronary artery were simulated, using a finite volume method. Coronary angiogram and Doppler ultrasound measurement of the proximal left coronary flow velocity were performed in humans. Inlet wave velocity distribution obtained from in vivo data of the intravascular Doppler study allowed for input of in vitro numerical simulation. Hemodynamic variables, such as flow velocity, pressure and shear stress of the left anterior descending coronary bifurcation site were calculated. We found that there were spatial fluctuation of flow-velocity and recirculation areas at the curved outer wall of the left anterior descending coronary artery, which were due to the differences of flow-velocity and shear stress, especially during the declaration phase of pulsatile flow. This study suggests that rheologic properties may be a part of the atherogenic process in the coronary bifurcated and curved areas.


Subject(s)
Coronary Artery Disease/etiology , Coronary Artery Disease/physiopathology , Coronary Vessels/physiopathology , Hemodynamics/physiology , Models, Cardiovascular , Biomechanical Phenomena , Blood Flow Velocity/physiology , Blood Pressure/physiology , Homeostasis/physiology , Humans , Pulsatile Flow , Stress, Mechanical
12.
Neuroreport ; 9(3): 367-72, 1998 Feb 16.
Article in English | MEDLINE | ID: mdl-9512373

ABSTRACT

This study was conducted to determine whether nitric oxide (NO) is involved in the maintenance of behavioral signs of neuropathic pain induced by tightly ligating the left L5 and L6 spinal nerves. Neuropathic rats showed behavioral signs representing mechanical allodynia, cold allodynia and cold-stress exacerbated ongoing pain. Mechanical allodynia was suppressed by Nomega-nitro-L-arginine methyl ester (L-NAME; 200, 100, 50, 10 microM/kg, i.p.), a nitric oxide synthase inhibitor, in a dose-dependent manner. Cold allodynia and cold-stress exacerbated ongoing pain was also attenuated by L-NAME. Neither Nomega-nitro-D-arginine methyl ester (D-NAME; 200 microM/kg) nor saline changed any of the neuropathic pain behaviors. These results suggested that NO plays an important role in the maintenance of the behavioral signs of neuropathic pain and is involved in common steps in the maintenance of the different modalities of pain such as mechanical allodynia and cold allodynia.


Subject(s)
Behavior, Animal/physiology , Neuralgia/physiopathology , Nitric Oxide/physiology , Animals , Disease Models, Animal , Enzyme Inhibitors/pharmacology , Male , NG-Nitroarginine Methyl Ester/pharmacology , Neuralgia/psychology , Nitric Oxide Synthase/antagonists & inhibitors , Rats , Rats, Sprague-Dawley , Stereoisomerism
13.
Neuroscience ; 81(2): 527-34, 1997 Nov.
Article in English | MEDLINE | ID: mdl-9300439

ABSTRACT

Tight ligation of the fifth and sixth lumbar segmental nerves in the rat provides a model of neuropathic pain. We used this model to assess the changes in primary afferent input to the dorsal horn in neuropathic pain syndromes. Dorsal roots and ganglia were examined for up to 32 weeks following segmental nerve ligation. Stereologic and morphometric techniques revealed a notable decrease in the numbers of dorsal root ganglion cells and unmyelinated dorsal root axons by six weeks post-injury. By 32 weeks following segmental nerve ligations, the numbers of dorsal root ganglion cells have dropped to 50% of pre-ligation levels while the numbers of dorsal root axons have increased to normal levels predominantly due to sprouting of myelinated fibres. These findings indicate that although there is a great loss of dorsal root ganglion cells, there is dramatic sprouting of myelinated fibres and possibly some sprouting of unmyelinated fibres in the dorsal roots. Additionally, a difference in the responses of unmyelinated and myelinated fibres to this peripheral nerve injury is revealed. These changes in dorsal root ganglion cells and their central axons may underlie certain aspects of abnormal pain syndromes because of changes in the types and quantity of input the dorsal horn receives.


Subject(s)
Axons/physiology , Ganglia, Spinal/physiology , Peripheral Nervous System/injuries , Animals , Cell Count , Disease Models, Animal , Ligation , Male , Rats
14.
J Korean Med Sci ; 12(4): 340-52, 1997 Aug.
Article in English | MEDLINE | ID: mdl-9288635

ABSTRACT

The aim of the present study is to verify the functional and anatomical neural pathways which innervate the urinary bladder in the central nervous system of the rat. To identify the functional neural pathway, the urinary bladder was stimulated by infusing formalin for 2 h. Then, brain and spinal cord were dissected out and immunohistochemistry was done by using anti-c-fos antibody. Many c-fos immunoreactive (IR) neurons were identified in the telencephalic cortical areas and in several brainstem nuclei, which are known mostly to be related with urinary bladder. In the spinal cord, a number of c-fos IR neurons were found in the lamina I, IIo, dorsal gray commissure, sacral parasympathetic nucleus. To identify the anatomical neural pathway of the urinary bladder, Pseudorabies virus (PRV) was injected into the wall of urinary bladder and was identified with anti-PRV by using immunohistochemistry. Most PRV labeled neurons were found where c-fos IR neurons were identified and few of them were also in the areas where c-fos IR neurons were not found, e.g., prefrontal cortex, agranular insular cortex, and subfornical organ. In the spinal cord, PRV labeled cells were found all over the gray matter. The present study presents morphological evidence demonstrating the supraspinal areas are related with the neural control of the urinary bladder and most functional neural pathway of the urinary bladder is well consistent with the anatomical neural pathway except in some telencephalic cortical areas.


Subject(s)
Central Nervous System/anatomy & histology , Herpesvirus 1, Suid/isolation & purification , Proto-Oncogene Proteins c-fos/analysis , Urinary Bladder/innervation , Animals , Female , Immunohistochemistry , Neural Pathways/anatomy & histology , Rats , Rats, Sprague-Dawley
15.
Neuroreport ; 8(9-10): 2149-53, 1997 Jul 07.
Article in English | MEDLINE | ID: mdl-9243601

ABSTRACT

Previous studies showed that heat-hyperalgesia and mechanical allodynia produced by chronic constrictive injury of the sciatic nerve were differentially sensitive to the NMDA receptor antagonist dextrorphan and to morphine and other opioid receptor agonists. These results support the hypothesis that different kinds of neuropathic pain symptoms are caused by different pathological mechanisms. In the present study we determined whether mechanical and thermal allodynia produced by unilateral transection of the 'superior' caudal trunk which innervates the tail in rats were differentially sensitive to the non-competitive NMDA receptor antagonist MK-801. Injection of MK-801 (0.3 mg/kg, i.p.) prior to nerve injury delayed the emergence of both types of allodynia; the antagonist-treated rats exhibited neither mechanical nor thermal allodynia at least for 4 days after the injury, whereas untreated control rats exhibited clear signs of allodynia from the first day after the injury. MK-801 injection on post-injury day 14, when the allodynia was near peak severity, suppressed temporarily both the mechanical and thermal allodynia. These results suggest that the mechanical and thermal allodynia from partial denervation of the tail are both dependent on NMDA receptors in their induction and maintenance. Thus, our results do not support the notion that different pathological mechanisms underlie different modalities of neuropathic pain from partial peripheral nerve injury.


Subject(s)
Pain/physiopathology , Peripheral Nervous System/injuries , Receptors, N-Methyl-D-Aspartate/metabolism , Animals , Disease Models, Animal , Dizocilpine Maleate/pharmacology , Excitatory Amino Acid Antagonists , Male , Rats , Rats, Sprague-Dawley , Reaction Time/physiology , Receptors, N-Methyl-D-Aspartate/physiology , Temperature
16.
Brain Res ; 751(2): 275-80, 1997 Mar 21.
Article in English | MEDLINE | ID: mdl-9099815

ABSTRACT

Peripheral nerve injury in a rat model (spinal nerve ligation) of neuropathic pain triggers sprouting of sympathetic fibers in the dorsal root ganglion (DRG). This sympathetic sprouting has been suggested as an important underlying mechanism for pain behaviors. To investigate the possibility of functional interaction between sprouted sympathetic fibers and sensory neurons, the present study examined the fine morphology and structural relationship between sympathetic fibers and the DRG neurons by electron microscopy. Sympathetic postganglionic fibers, as identified by electron microscopic immunostaining for tyrosine hydroxylase (TH), were all unmyelinated fibers and some of them ended as growth cones. In addition, many vesicle-containing axonal enlargements (we will refer these as synaptic varicosities) were found in the interstitial space around DRG neurons, and some were enclosed within the satellite cell capsule which surrounded the DRG soma. The presence of sympathetic synaptic varicosities near or in apposition with either the DRG somata or their processes provides a structural basis for possible interactions between sensory neurons and sympathetic fibers in the DRG of neuropathic rats.


Subject(s)
Ganglia, Spinal/physiopathology , Spinal Nerves/injuries , Sympathetic Nervous System/physiopathology , Synapses/physiology , Animals , Ganglia, Spinal/enzymology , Ganglia, Spinal/pathology , Immunohistochemistry , Ligation , Male , Microscopy, Electron , Nerve Fibers/enzymology , Nerve Fibers/physiology , Rats , Rats, Sprague-Dawley , Sympathetic Nervous System/enzymology , Synapses/ultrastructure , Tyrosine 3-Monooxygenase/metabolism
17.
Exp Brain Res ; 113(2): 200-6, 1997 Feb.
Article in English | MEDLINE | ID: mdl-9063706

ABSTRACT

To characterize various animal models of neuropathic pain, we compared three previously developed rat models using the same behavioral testing methods. These models involve: (1) chronic constriction injury by loose ligation of the sciatic nerve (CCI); (2) tight ligation of the partial sciatic nerve (PSL); and (3) tight ligation of spinal nerves (SNL). Comparisons were made for the time course of behavioral signs representing various components of neuropathic pain as well as for the effects of surgical sympathectomy. In general, all three methods of peripheral nerve injury produced behavioral signs of both ongoing and evoked pain with similar time courses. However, there was a considerable difference in the magnitude of each pain component between models. Signs of mechanical allodynia were largest in the SNL injury and smallest in the CCI model. On the other hand, behavioral signs representing ongoing pain were much more prominent in the CCI model than in the other two. Although the behavioral signs of neuropathic pain tended to decrease after sympathectomy in all three models, the change was most evident in the SNL model. The results of the present study suggest that the three rat models tested have contrasting features, yet all are useful neuropathic pain models, possibly representing different populations of human neuropathic pain patients.


Subject(s)
Disease Models, Animal , Pain/physiopathology , Animals , Male , Rats , Rats, Sprague-Dawley
18.
J Comp Neurol ; 376(2): 241-52, 1996 Dec 09.
Article in English | MEDLINE | ID: mdl-8951640

ABSTRACT

The extent of the sprouting of sympathetic postganglionic fibers in the dorsal root ganglion (DRG) and the peripheral nerves was examined in neuropathic rats at different postoperative times. After the L5 and L6 spinal nerves were ligated on one side, three different pain behavior tests (representing mechanical allodynia, cold allodynia, ongoing pain exacerbated by cold stress) were performed at various time intervals. The sympathetic postganglionic fibers were visualized by immunostaining with antibodies to tyrosine hydroxylase (TH). In the neuropathic rats, all three pain behaviors were fully developed within 3 days after the surgery, maintained up to 2 weeks, and then started to decline gradually afterward. At 20 weeks after neuropathic surgery, pain behaviors were reduced significantly compared to the peak response, but were still higher than the presurgery levels. Sympathectomy, performed 4 days after neuropathic surgery, almost completely abolished the signs of mechanical allodynia and ongoing pain behaviors, and it reduced the behaviors of cold allodynia to approximately half. The numerical density of sympathetic fibers in the DRG of an injured segment was significantly higher at 1, 4, and 20 weeks after neuropathic surgery as compared to the normal, suggesting that there is sprouting of sympathetic fibers in the DRG after peripheral nerve injury. Sprouting of sympathetic fibers in the DRG was extensive as early as 2 days after the spinal nerve ligation, and the sprouted fibers were almost completely eliminated after sympathectomy. The data suggest that sympathetic innervation of the DRG may play an important role in the development and maintenance of sympathetically maintained neuropathic pain.


Subject(s)
Causalgia/physiopathology , Ganglia, Spinal/physiopathology , Neurons, Afferent/physiology , Pain/physiopathology , Spinal Nerves/injuries , Sympathetic Fibers, Postganglionic/physiopathology , Animals , Causalgia/therapy , Cold Temperature/adverse effects , Ganglionectomy , Ligation , Male , Nerve Fibers/enzymology , Nerve Tissue Proteins/analysis , Rats , Rats, Sprague-Dawley , Stress, Mechanical , Sympathectomy , Sympathetic Fibers, Postganglionic/enzymology , Tyrosine 3-Monooxygenase/analysis
19.
Am Heart J ; 132(1 Pt 1): 78-83, 1996 Jul.
Article in English | MEDLINE | ID: mdl-8701879

ABSTRACT

With a cat model of regional cardiac ischemia, we examined whether the incidence of reperfusion-induced ventricular fibrillation (VF) could be reduced by ventricular premature beat (VPB)-driven intermittent reperfusion. In addition, we assessed whether the effect of the intermittent reperfusion was comparable with that of ischemic preconditioning in suppressing the VF. Of 15 cats subjected to uninterrupted reperfusion after 20-minute occlusion of the left anterior descending coronary artery, 13 (86.70%) had VF, whereas only 1 (7.1%) of 14 cats subjected to the VPB-driven intermittent reperfusion had VF. This incidence of VF was significantly lower than that of the animal group subjected to uninterrupted reperfusion. However, it was not statistically different from that (3 of 15) of the group subjected to a 10-minute episode of the coronary artery occlusion before the 20-minute occlusion (i.e., "ischermic preconditioning"). Our results suggest that the VPB-driven intermittent reperfusion (i.e., "postconditioning") is very effective in preventing reperfusion-induced VF and as good as, if not better than, ischemic preconditioning.


Subject(s)
Coronary Circulation , Myocardial Ischemia/therapy , Myocardial Reperfusion Injury/prevention & control , Myocardial Reperfusion/methods , Ventricular Fibrillation/prevention & control , Ventricular Premature Complexes/physiopathology , Animals , Cats , Disease Models, Animal , Electrocardiography , Incidence , Male , Myocardial Ischemia/physiopathology , Tachycardia, Ventricular/etiology , Tachycardia, Ventricular/prevention & control , Ventricular Fibrillation/etiology , Ventricular Premature Complexes/classification
20.
Yonsei Med J ; 36(5): 448-56, 1995 Nov.
Article in English | MEDLINE | ID: mdl-8546003

ABSTRACT

Atrial fibrillation may occur in patients with a variety of cardiovascular or chronic disease as well as in normal subjects. Many authors reported that atrial fibrillation occurs in patients with thyrotoxicosis. It is reported that a low serum thyrotrophin concentration in an asymptomatic person with normal serum thyroid hormone concentrations can be a independent risk factor for developing atrial fibrillation. But we focused on the significance of serum thyroid stimulating hormone (TSH) in the euthyroid patient with atrial fibrillation whose serum level of T3, T4, fT4, and even TSH were absolutely within normal range. On our results, there was no significant differences in age, sexual distribution, and left ventricular ejection fraction between the patients group of paroxysmal and chronic persistent atrial fibrillation (p > 0.05), but there was larger left atrial dimension (LAD) and more cases of rheumatic heart disease in the chronic persistent atrial fibrillation group and there was more cases of lone atrial fibrillation in the paroxysmal atrial fibrillation group (p < 0.05). There was no significant differences in serum levels of T3, T4, fT4 between paroxysmal and chronic persistent atrial fibrillation, but significantly lower serum TSH was found in patients with paroxysmal atrial fibrillation (p < 0.001), and these findings were more significant after the control of hemodynamic change (p < 0.001 vs p < 0.05). The discriminant value in serum TSH between the paroxysmal and chronic atrial fibrillation group was 1.568U/mL with about 76% of predictive power. There was significantly lower serum TSH in paroxysmal atrial fibrillation in all age groups (p < 0.05). There was a significantly higher prevalence of cerebral thromboembolic events in chronic persistent (27.7%) and disease-associated (15.0% atrial fibrillation than in the paroxysmal (3.3%) and lone (4.5%) atrial fibrillation group (p < 0.001). Therefore, we suggest that serum TSH below the serum concentration of 1.5U/mL can be a risk factor for developing atrial fibrillation when the serum level of T3, T4, fT4, and even TSH were within absolutely normal range.


Subject(s)
Atrial Fibrillation/blood , Thyroid Gland/physiopathology , Thyrotropin/blood , Adult , Aged , Aged, 80 and over , Analysis of Variance , Atrial Fibrillation/physiopathology , Chi-Square Distribution , Female , Humans , Male , Middle Aged , Thyroid Function Tests
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