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Computed tomography-guided biopsy of the spine is considered a safe and relatively inexpensive examination tecnique. We performed CT-guided biopsy for 8 cases without any complications. These cases were 6 thoracic, 1 lumber and 1 sacral. Pathologic examinations revealed 3 primary tumors, 2 metastases, 2 tuberculosis and 1 pyogenic spondylitis. CT-guided biopsy is an important tool in the evaluation of spinal lesions.

We have studied 35 patients (25 female and 10 male) with low-back pain who were managed with aquatic exercises after an appropriate period of treatment for their condition in the medical institution. The exercises employed consisted of strengthening exercises for the abdominal, gluteal, and leg muscles, stretching of the back, hip, hamstrings, and calf muscles, walking in water, and swimming. All the patients had been participating in the exercise program for more than 6 months. The frequency of performing exercises was once a week for 7 patients, twice a week for 19, and 3 or more times a week for the remaining patients. The method used in this study was a survey questionnaire which was composed of questions about the patient's physical and psychological condition. Those patients who had performed exercises twice or more in a week showed a more significant improvement in the physical score than those who performed exercises only once a week. More than 90% of the patients felt they had improved after 6 months of participation in the program. The improvement in physical score was independent of the initial ability in swimming. The results obtained suggested that exercises in water may be one of the most useful modes of exercise for a patient with low-back pain.

A spinal epidural hematoma may result from one of many causes, including coagulopathy, trauma, a vascular lesion, iatrogenesis, and spontaneous occurrence2,4,6,7,11,12. Groen and van Alphen7 reviewed the cases of 333 patients who had a spontaneous spinal epidural hematoma; they had excluded patients in whom the hematoma had occurred after a traumatic episode involving spinal dislocation or fracture, after epidural anethesia, after diagnostic lumbar puncture, after an operation, or in association with a tumor in the spinal canal. Of the 333 patients, forty (12 per cent) had a lumbar epidural hematoma. Overall, fifty-five (17 per cent) of the patients were younger than twenty years old, and only four (7 per cent) of these young patients had a spontaneous lumbar epidural hematoma. Boyd and Pear reported that a hematoma caudad to the level of the conus medullaris was more likely to be chronic because the spinal roots appear to tolerate pressure better than the spinal cord does. In a review of the literature, we found four cases of lumbar epidural hematoma in patients who were younger than twenty years old3,7,17,21, and we compared these cases with that of our patient. A chronic spinal epidural hematoma is rare in young patients; it occurred in only two of the patients, including ours. We report the case of a young patient who had a chronic lumbar epidural hematoma and spondylolysis at the third lumbar vertebra. The patient, a seventeen-year-old high-school student, had radicular pain in the left lower extremity when he was first seen by us in 1991. He was a rugby player (center prop position number three), and, in early December 1991, he had pain on the left side of the low back …

To examine the role of vascular endothelial growth factor (VEGF), an endothelial cell specific growth factor, in rheumatoid arthritis (RA), serum concentration of VEGF was examined in patients with RA, osteoarthritis (OA), systemic lupus erythematosus (SLE), systemic sclerosis (SS) and control subjects. Serum C-reactive protein (CRP) level, erythrocyte sedimentation rate, white blood cell count and rheumatoid factor titer were also determined in patients with RA. The serum concentration of VEGF was significantly higher in patients with RA than in controls (p0.01), and patients with OA (p0.05), SLE (p0.05), and SS (p0.05). The serum concentration of VEGF correlated with serum levels of CRP (r = 0.698, p0.0001). The serum concentration of VEGF before treatment was significantly higher than that after treatment in patients with RA who experienced clinical remission (p0.05). Our data suggest that VEGF is involved in the pathogenesis of RA and that measurement of serum concentration of VEGF is a noninvasive, useful method for monitoring the disease activity of RA.

We prospectively investigated and compared the results from wire fixation and those from pedicle screw fixation for an unstable lumbar spine. Between April 1992 and July 1996, we surgically managed 44 cases of unstable lumbar spine using either wire fixation or pedicle screw fixation. Wire fixation was employed for 22 patients (11 male and 11 female, with a mean age at surgery of 51.1 years), and pedicle screw fixation was employed for 22 patients (8 male and 14 female, with a mean age at surgery of 57.1 years). The results showed no difference in % slip, slip-angle, frequency of bone union, or in frequency of instrument failure between those that had received wire fixation and those that had received pedicle screw fixation. In those with lumbar spondylolisthesis, the operative results were excellent or good in only 7 (53.8%) of 12 cases treated with wire fixation and in 13 (81.6%) of the 16 treated with pedicle screw fixation. In those with lumbar disc herniation or lumbar canal stenosis, there was no significant difference in the results between those that had been treated with wire fixation and those that had been treated with pedicle screw fixation.We concluded from these short term results that wire fixation was sufficient for an unstable spine with lumbar disc herniation or lumbar canal stenosis, while pedicle screw fixation was better than wire fixation for an unstable spine with lumbar spondylolisthesis.

We present five patients with acute traumatic hemarthrosis of the knee who also had hemorrhage within the bone marrow around the knee detected by magnetic resonance imaging. No additional bony, ligamentous, meniscal or osteochondral injuries were evident from clinical examination, initial and repeated plain radiographs, or magnetic resonance imaging. The main symptoms were sharply localized pain and tenderness of the contused area. When hemarthrosis was demonstrated at the first office visit, three cases had fat droplets in the blood. Two patients with hemarthrosis of the knee undergoing arthroscopy showed no obvious lesions of intra-articular structures. Instead they showed congestion of the joint capsule located in accordance with the traumatic episode. Magnetic resonance imaging demonstrated marrow abnormalities as diffusely low and high signal intensity areas in T1-weighted and T2-weighted images, respectively, in locations consistent with the traumatic episode and the symptoms. These disappeared within an average of 13 weeks (range in 4 cases, 12 to 16 weeks). These findings were considered diagnostic of bone contusion. Symptom duration was about 2 weeks in all cases. In conclusion the clinician should consider the possibility of coexisting bone contusion in cases of acute traumatic hemarthrosis of the knee with no evidence of bone or intra-articular lesions on clinical examination and conventional radiographs.

Thirteen cases of cystic lesions of soft tissue were treated with a fibrin adhesive agent. The average age of patients was 62.5 years, ranging from 36 to 82 years. The length of follow-up ranged from 3 months to 2 years 2 months. Results were rated as excellent in 12 cases with one recurrence in a case with bursitis of the olecranon that was thick-walled. NO side effccts of the fibrin agent were obserced.

We report a case with a necrotizing fasciitis-like disease in the bilateral lower extremities of an 83-year-old woman which developed in the course of treating her pyogenic arthritis of both knees.The patient had her left leg amputated above the left knee and her right leg skin grafted following currettage of the right lower leg.Magnetic resonance imaging (MRI) was very useful for providing details of the extent of this disease.

Five cases of Galeazzi fractures were treated during a twenty-year period in our clinic. The average age of patients at injury was twenty-five years (range, from nineteen to fifty-eight).Three cases were treated by closed reduction and internal fixation; by Rush pin in one case, K -wires in others. Two cases were treated by open reduction and additional fixation with plate or wires. Immobilization by plaster cast was applied for all cases in supinated position of the forearm. Supination contracture of the forearm was the most common in problems. A Lauenstein operation was effective for severe supination contracture caused by malreduction of the distal radioulnar joint. Early treatment with complete reduction of the dislocated distal radioulnar joint is the most important factor for the prognosis in this fracture.

Stress fractures of the tarsal navicular bone are rare injury and assessing its healing is difficult. Tenderness over the tarsal navicular on physical examination is the most reliable sign for assessing fracture healing. However, it is desirable to assess fracture healing with some imaging method. We used serial magnetic resonance imaging (MRI) to assess healing in a patient with a tarsal navicular stress fracture. MRI was useful for the assessment of fracture healing of tarsal navicular stress fracture in our case.

We present 4 cases of cervical myelopathy caused by the calcification of the yellow ligament. All cases were female and teir average age was 62 (range: 53 to 73) years. Plain radiographs showed round-shaped calcification in the spinal canal; 2 between C5/6, Ibetween C6/7, and 1 between C3/4, C4/5, and C5/6 from the lateral view. Computed Tomography (CT) clearly showed high density tumor-like mass at the sites corres pording to the plain radiographs which compressed the spinal cord. Laminoplasty from C3 to C7 was employed for operative treatment and produced good result in all cases.

We reviewed the results of operative treatment in 32 patients with lumbar disc herniation in adolesence. During 1991-1996 we operated on 18 patients (13 men, 5 women, mean age at surgery, 16.4 years) with percutaneous discectomy (PD); 14 patients (10 men, 4 women, mean 15.5 years) with open discectomy. The post operative results, were excellent or good in 11 of 18 patients (61.1%) with PD, and in 13 of 14 patients (92.5%) with open disectomy, respectively. The average period of recovery to playing sports was 1.75 months with PD, 2.90 months with open disectomy. One of the important things in surgical treatment of lumbar disk herniation in adolesence is the period of recovery to full sporthing activities. In this study, it is suggested that PD is the most useful treatment for lumbar disk herniation in adolesence.

Rehabilitation of the postoperative knee following anterior cruciate ligament (ACL) reconstruction has evolved and improved significantly over the past decade. We experienced two different methods of rehabilitation, and compared the post-operative course following each method.Twenty-seven patients who underwent ACL reconstruction at our institute without other ligamentous injuries were used for this study. We divided these patients into two groups dependant upon postoperative rehabilitation, (fixation group: 10, early motion group: 18). In the fixation group, the knee was immobilized for 2 weeks postoperatively. In the early motion group, a continuous passive motion machine was used after 3 days immobilization.In the early motion group, the angle of knee extension was significantly different from that in the fixation group (p. 0.4 and 8 week. p

Twenty patients who underwent open meniscal repair were evaluated by second look arthroscopy. An average age of the patients was 22.8 years. The time from repair to repeat arthroscopy ranged from 4 months to 5 years (average: 1 years and 7 months). The operative indications were 1) peripheral longitudinal tear, 2) no degeneration of the body, and 3) unstable tear over 1cm in length. All torn menisci were repaired by modified Humberg's method. Associated torn ligaments were also reconstructed when necessary. No patients except one had a symptom of the retear at second arthroscopy. Arthroscopic results were graded as follows: “healed” -no defect (n=18, 90%), “incompletely healed” -a partial defect without hypermobility (n=1, 5%), and “unhealed”-hypermobile defect (n=1, 5%). Out of 18 patients who were evaluated as healed, one had a retear of the repaired meniscus after second arthroscopy. Although this procedure provided good results, it is problematic that a longitudinal tear in more inner part can not be repaired in this technique.

Healing process of torn human anterior cruciate ligament (ACL) was studied histologically. Torn anterior cruciate ligaments were obtained from 21 patients at primary ACL reconstruction and stained with hematoxylin and eosin. Patients age was from 16 to 40 years. The interval between initial injury and operation ranged from 2 to 30 days. At 2 days after ACL injury, fibroblasts were not seen in the torn ligament and lymphocytes appeared in the injured ligament. Although vascular endothelial capillary buds and fibroblasts appeared around the torn ligament at 11 days, few fibroblasts were seen in it. At 30 days, torn ligament shrank macroscopically and resembled scar tissue with irregular alignment of fibroblast and collagen fiber. In conclusion, torn ligament is not healed probably due to few fibroblasts proliferation.

STUDY DESIGN An assessment of the value of external fixation with or without percutaneous discectomy for the management of scoliosis in young rabbits with induced progressive thoracic scoliosis. OBJECTIVES To investigate in an experimental setting the effect of external fixation with or without percutaneous discectomy for the management of scoliosis, as a preliminary study to precede clinical consideration. SUMMARY OF BACKGROUND DATA External fixation of the spine using percutaneous transpedicular screws has been used clinically for cases of traumatic spinal injury, infectious spine, or chronic low back pain caused by a disc lesion. Percutaneous discectomy for the management of scoliosis has been reported. METHODS Thirty-two young rabbits underwent partial resection of the right lower ribs. Nine rabbits were not treated after production of scoliosis and were followed as controls. At 4-6 weeks after production of scoliosis, in 23 animals, Kirschner wires were inserted percutaneously into the T9-T10 and L1-L2 disc space, and both ends were attached to an external fixator after correction of the scoliosis. In 8 of those 23 animals, percutaneous discectomy was also performed at the apex of the caudal compensatory curvature. RESULTS In these 23 animals, the initial correction by fixation on of the caudal vertebrae was accompanied by a derotation in the apex. Five animals treated with external fixation only and four treated with combined percutaneous discectomy survived with external fixation until the age of 17 weeks and were followed to the natural cessation of the curve progression, at which the fixation was removed and a final assessment was made. The mean progression of curvature was 15.8 degrees in the group of five animals with external fixation only, and 33.8 degrees in the controls. In the group of four animals treated with supplementary percutaneous discectomy, however, the treated disc space became rigid, and the mean progression of curvature after removal of the fixation was only 5.3 degrees. CONCLUSIONS The results of the current study suggest the potential for external fixation to allow for derotation and, when combined with percutaneous discectomy, to offer a feasible method of managing scoliosis in the human adolescent. This study was a preliminary experimental study; further experimental studies are planned to develop this novel technique.

We report 4 cases of patellar fracture with skin injury over the patella which were treated operatively immediately after onset with a new reduction technique using Ilizarov pins. This technique made it possible to perform early operative treatment even in the cases with skin injury over the patella which prevents conventional surgical approach.

Study design Retrospective evaluation of results in 23 cases of early-stage pyogenic spondylitis treated with percutaneous suction aspiration and drainage. Objectives To evaluate the efficacy of percutaneous suction aspiration and drainage as a treatment method for early-stage pyogenic spondylitis. Summary of background data Traditional surgical treatment for pyogenic spondylitis has the disadvantage of increased morbidity caused by the extensive exposure required in the presence of infection. Recently, a few case reports have described minimally invasive treatment for pyogenic spondylitis in which percutaneous suction aspiration was used. However, the efficacy of this new treatment has not yet been evaluated. Methods All charts, radiographs, and bacteriologic and histologic findings were reviewed. All 23 patients who received the new treatment were observed clinically and radiographically, to evaluate the efficacy of the treatment. Results To date, all patients have been observed for more than 2 years. Twenty (87%) of the 23 patients have shown good results according to the evaluation. The causative organism was identified using tissue culturing in 12 (52%) of the 23 patients. The causative organism was Staphylococcus aureus in 8, and Staphylococcus epidermidis, Candida albicans, Pseudomonas aeruginosa, and Propionibacterium acnes in 1 each. Back pain as the major symptom in these patients was relieved within an average of 9.4 days after the operation. However, the patient in whom the spondylitis was caused by Candida albicans has received this new treatment twice without success. Conclusions Evaluation of percutaneous suction aspiration with drainage shows that it is an effective treatment for early-stage pyogenic spondylitis.

It is difficult to assess the healing of the medial malleolar stress fracture. We describe a case of medial malleolar stress fracture which was monitored its healing with repeated magnetic resonance images.

Edwardsiella tarda (E. tarda) is gram negative enterobacteriaceae which has been found generally in animal hosts and occasionally in human feces. We have reported a case of sepsis caused by E. tarda, complicated panophthalmitis and pyogenic spondylitis. A 39-year old patient suffered from fever, polyarthralgia and lumbago. We performed blood culture, from which E. tarda was isolated. Spinal CT scan showed destruction and osteogenesis of the fourth and fifth lumbar vertebral body and cranial CT scan showed destruction of the right lens. So we diagnosed sepsis with pyogenic spondylitis and panophthalmitis. We suspected that chronic ethanol administration reduced the resistance to infection of E. tarda which caused sepsis.

We report a rare case of spondylolysis that occurred at 3 sites in the fifth lumbar vertebra involving the bilateral pars interarticularis and the center of the right lamina. This is the first such case in the world literature.

An 8-year-old boy who had no significant past medical history had right leg pain for 2 months while practicing judo and with walking. He had been participating in 2 hours of judo practice twice a week and running almost every day for 2 years. He denied direct trauma to the leg. The anterior midshaft of the right leg was tender, without swelling or redness. Plain radiographs revealed a lucent area in the anterior cortex of the midshaft of the tibia. A bone scan with technetium-99 demonstrated locally increased uptake at the site of symptoms. MRI showed an abnormal signal intensity at the same spot. These findings were compatible with a stress fracture of the midanterior cortex of the tibia. He was treated with cast immobilization, no weight bearing and ambulation on crutches. The cast was removed after 2 months and he had no pain on standing, although he complained of mild tenderness over the anterior midshaft of the tibia. The lucent area was visible on repeated radiographs, but less distinct than on the initial radiographs. We removed the cast and permitted ankle motion, no weight bearing and use of crutches, but prohibited physical activities for 3 more months. 3 months later, he still had some pain and radiographs demonstrated a lucent area in the anterior cortex with linear sclerotic changes in the upper third of the tibia. We continued prohibition of weight bearing on the right leg for 2 more months. Nevertheless, 2 months later he still had pain and radiographs revealed sclerotic changes in the lower third of the tibia, in addition to findings in the midshaft and upper third. At that time, he confessed that he had been running now and then in order to maintain his competitive level with fellow athletes. We strictly prohibited weight bearing and sports activities, except swimming. 4 months later, he said he had been following our recommendation and had no symptoms and radiographs were normal. 1 year later he had no symptoms. He had a normal physical constitution, normal skin condition, normal ocular and auditory systems, normal laxity and range of motion in his joints, with normal alignment of his legs. Laboratory findings including blood count, sedimentation rate, calcium, phosphate, alkaline phosphate, thyroid and parathyroid hormones were normal. There was no evidence of rickets at the end of the long bones and bone density was normal.

The mechanism of an inhibitory effect of histamine on the sensitivity of frog skeletal muscle endplate was analyzed by studying the dose-response relation between the quantity of ACh applied iontophoretically and the ACh-induced postsynaptic current (ACh current), and also the interaction between histamine and erabutoxin-b (ETX-b). The results obtained show that histamine, like curare, decreased the sensitivity of ACh-receptor in a competitive manner.

The effects of histamine on the acetylcholine (ACh) receptor-channel complex were examined by means of voltage-clamp at the frog endplate. ACh was ionophoretically applied to the endplate. Histamine was added to the perfusate. Histamine (100 nM - 1 mM) reversibly depressed the peak amplitude of the ACh-induced inward current in a dose-dependent manner. The double reciprocal plot of the dose-response relationship between the peak ACh current and the amount of ACh applied suggested that histamine (100 microM) depressed the ACh-induced current in a competitive manner. Histamine prevented the specific ACh binding site within the receptor-channel complex from binding erabutoxin, a sea-snake venom, which binds irreversibly to the specific ACh binding site. Histamine had no detectable effects on the equilibrium potential of the endplate current but shortened the half-decay time of the endplate current in a voltage-dependent manner. It was therefore concluded that histamine blocks not only the specific ACh binding site but also interacts with the ACh-channel site. The present experiments strongly suggest that histamine can act as an antagonist to modulate nicotinic cholinergic transmission.

Thirteen shoulders of twelve patients (7 male and 5 female) of recurrent anterior dislocation of the shoulder were operated on by modified Bristow methods, 7 cases were operated on by Bristow-McMurray procedure and 6 cases by Bristow-May procedure, from 1979 to 1988 in our clinic.The dicision of choosing the procedure is based on 3 factors: first is the status of the injured shoulder capsule determined by the arthrogram, second is the number of recurrent dislocations, and third is the occupation of the patient.In none of our patients was there a recurrence. Only one complication was a broken screw which produced no problem to the patient.The patients operated by Bristow-May procedure had more limitation of the motion especially in external rotation than those operated by Bristow-McMurray procedure. Nevertheless all patients stated that they could resume various activities which they had not been able to do because of recurrent dislocations.

Intracellular recordings were made from submucous plexus neurones of the guinea-pig caecum in vitro. The peak amplitude of the adrenergic inhibitory postsynaptic potential (IPSP) was depressed by mianserin in a dose-dependent manner (300 nM-100 microM). This was due to a direct blockade of postsynaptic alpha 2 adrenoceptors. The nicotinic excitatory postsynaptic potential (EPSP) and the non-cholinergic EPSP were not affected by mianserin (100 microM). The presynaptic inhibition of the release of acetylcholine, mediated by presynaptic alpha 2 receptors, was also blocked by mianserin (30 microM). The results suggest that mianserin antagonizes both pre- and post-synaptic alpha 2 adrenoceptors in enteric plexus neurones.

With intracellular and voltage-clamp recording techniques, we have demonstrated that the glucocorticoids, prednosolone and hydrocortisone at a concentration of 5 μM to 1 mM, reversibly depressed γ-aminobutyric acid (GABA)-induced responses on primary afferent neurons of bullfrogs. An analysis with dose-response curves revealed that the glucocorticoids decreased the sensitivity of the GABA A receptor in a non-competitive manner. We suggest that glucocorticoids act as an antagonist of the GABA A receptor on primary afferent neurons, probably by reducing the number of functional GABA A receptor ionic channel complexes.

Sixty-two elbow joints of fifty out-patients with rheumatoid arthritis were examined about radiological findings. Radiological findings were classified according to the Steinbrocker's classification and involved localization; humero-ulnar (H-U) type, humero-radial (H-R) type and combined type.The results were as follows.1. At the onset of the symptom of the elbow joint, the Stage of it was already relatively high.2. Concerning the part of destruction occurred, combined type occupied the majority of cases.3. Progression of destruction in the elbow joints was slower than that in the wrist joints.The results suggested that it is necessary to take radiological examination at early period because destruction of the elbow joint progresses without symptom in the elbow joint.

In functional bracing for idiopathic scoliosis, the role of the lateral pad acting through the ribs is very important. There are few reports, however, about the inclination of the ribs and the effectiveness of the brace. The relationship of the rib-vertebral angle (R. V. A.) on a level with the apex vertebra to the final correction was examined in thirtyfive patients (4 males and 31 females). Average age in scoliotic group was 12 years and 11 months at time of first examination. A lateral curvature of 29.7 degrees of Gobb's angle at pre-bracing was finally restored to 21.1 degrees. (29.3 per cent as correction rate). Final correction rate was 41.9 per cent in the group (7 patients) with larger R. V. A. than control, while 26.1 per cent in the group (28 patients) with smaller R. V. A.. We conclude from the results described above that measurement of the R. V. A. of the apex vertebra is useful in estimating the effectiveness of under arm bracing.

Seventeen cases of non-union of the humeral shaft were treated for the last 20 years, 12 patients being male and 5 female. There were 3 cases in the proximal third of humeral shaft, 6 cases in the middle third and 8 cases in the distal third. Nine cases of those were transverse fractures. A cause of non-union was unsuitable treatment at injury. 12 cases showed bone union at the first operation, but 5 cases needed re-operation.According to the classification of non-union by Muller, an atrophic type was seen in 7 cases, and an elephant-foot type in 10 cases. Bone graft and decortication technique were combined in some cases. The atrophic type required an average of five months for bone healing. In the elephant-foot type, bone graft was not exactly essential.

Twenty-two femoral shaft fractures in 22 patients were treated by intramedullary nailing, 14 patients were operated with Kuntscher nail and 8 patients were with Ender nails. According to the winquest and Hansen classification, these fractures were classified in Type II or in Type III. The period when full-weight bearing was permitted was earlier in patients who was operated with Kuntscher nail than in Ender nails.However, the time of bone union in cases operated with Ender nails was the same as in cases with Kuntscher nails. The cases which showed radio-lucent zone at the distal points of Kuntscher nails were shorter in period of bone union than others without radio-lucent zone. These results suggested that elastic fixation was better than rigid fixation in operative teratment for femoral shaft fractures by closed intramedullary nailing.

1. Recent concept of postsynaptic modulation is reviewed on the basis ofliterature data and the results of our investigation using conventional intracellular and voltage-clamp recording methods, in vitro . 2. Experimental evidence provided that the sensitivity of nicotinic ACh receptors endowed on the postsynaptic membrane of the bullfrog sympathetic ganglia and of the frog skeletal muscle end-plate is either facilitated or inhibited by other neurotransmitters or neurohormones. 3. We propose that one neurotransmitter not only initiates its own postsynaptic potential but also regulates the efficacy of synaptic transmission mediated by a distinct neurotransmitter. as an endogenous “antagonist” or “sensitizer”.

Intracellular recordings were obtained from the frog sartorius muscle end-plate to investigate the effects of cholecystokinin octapeptide (CCK-8) on cholinergic transmission at the neuromuscular junction. A brief bath-application of CCK-8 (1 μM) produced a depression, followed by a long-lasting facilitation, of the amplitude and the quantal content of the end-plate potential (epp). CCK-8 had a biphasic effect, an initial depression followed by an augmentation of the frequency of the miniature epps. CCK-8 did not affect the sensitivity of the nicotinic receptor at the end-plate. These results suggest a significant role for CCK-8 in cholinergic transmission, possibly as a modulator of the evoked release of acetylcholine from motor nerve terminals.

Acute effects of glucocorticoids on the response to γ-aminobutyric acid (GABA) were examined in primary afferent neurons in bullfrog spinal ganglia, using intracellular and voltage-clamp recording techniques. Prednisolone and hydrocortisone (5 μM to 1mM) caused a dose-dependent decrease in the amplitude of GABA-induced depolarization, while having no effect on the membrane potential and resistance of the neuron. Prednisolone depressed the muscimol-induced depolarization. Nipecotic acid, a blocker of GABA uptake, did not influence the inhibitory action of prednisolone. Voltage-clamp analyses showed that the inward current induced by an iontophoretic application of GABA (GABA current) was suppressed by prednisolone and hydrocortisone. The depression of the GABA current is neither due to a blockage of open channels nor a facilitation of the desensitization of GABA receptors. Prednisolone shifted the dose-response curve of the GABA current downward. The double-reciprocal (Lineweaver-Burk) plot showed that the maximum GABA current was reduced by prednisolone, suggesting a non-competitive antagonism. These results suggest that glucocorticoids suppress the GABA-induced chloride current, decreasing the number of functional channels associated with GABA A receptor.