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1.
OBJECTIVE: To assess the effect of 1-year treatment with rilmenidine, an oxazoline compound that exerts its antihypertensive effects through binding to imidazoline receptors in the brainstem, on left ventricular hypertrophy (LVH) secondary to essential, mild-to-moderate hypertension [supine diastolic blood pressure (DBP)95-115 mmHg]. METHODS: We performed a double-blind, randomized, controlled (versus slow-release nifedipine) trial. Adjustment of treatment took place every month (M) between inclusion (MO) and an evaluation after 6 months (M6), then during M9 and after 1 year (M12) to achieve supine DBP values < or = 90 mmHg. Patients were dropped from our study if they had DBP> 95mmHg during two consecutive visits or DBP>115 mmHg on one occasion. The daily dosage of rilmenidine was 1 mg, and could be increased to 2 mg/day. The daily dosage of slow-release nifedipine was started from the beginning at the maximum dosage of 40 mg/day, so that there was no true adjustment of treatment despite the allocation of patients to a different unit in the case of DBP> 95 mmHg. The primary criterion was the change in left ventricular mass index (LVMI, g/m2), assessed by echocardiography, between MO and M12 for patients who completed the trial. RESULTS: After a 1-month placebo run-in period, 76 patients were selected and 73 were included (35 treated with rilmenidine and 38 treated with nifedipine). Fifteen patients withdrew from the study and two completed the study with a major deviation from protocol, leaving 56 patients (24 treated with rilmenidine and 32 treated with nifedipine) for a per-protocol analysis. Baseline demographic characteristics and history of arterial hypertension for the rilmenidine and nifedipine groups were similar, for included patients and for those taken into account for the per-protocol analysis. Between MO and M12, DBP in members of the per-protocol population was adequately controlled for those in the rilmenidine group (102.7+/-4.6 versus 88.5+/-7.1 mmHg, respectively) and for those in the nifedipine group (102.7+/-5.1 versus 85.6+/-79 mmHg, respectively). During MO, LVMI of patients in the rilmenidine group (176.9+/-41.3 g/m2) was slightly higher than that of patients in the nifedipine group (172.6+/-35.1 g/m2). During M12, LVMI was observed to have decreased both for patients in the rilmenidine group (to 154.8+/-40.2 g/m2, a decrease of 22.1+/-23.3 g/m2, P< 0.001) and for those in the nifedipine group (to 145.6+/-36.4 g/m2, a decrease of 26.9+/-29.5 g/m2, P< 0.001) but the difference between these two groups was not significant (P= 0.5). CONCLUSION: One-year treatment with a daily dosage of 1 or 2 mg rilmenidine achieves a significant reduction of left ventricular mass, which is not statistically different than that occurring with a daily dosage of 40 mg of slow-release nifedipine.  相似文献   

2.
The utility of clonidine for hypertensive patients presenting for major vascular procedures remains debatable. Twenty-one hypertensive patients presenting for aortic surgery were given clonidine (n = 11) or placebo (n = 10) in a double-blind, randomized manner. Clonidine was administered 6 micrograms/kg per os 120 min before induction of anesthesia and 3 micrograms/kg intravenously (i.v.) over 60 min from aortic declamping to skin closure. Anesthesia was induced with alfentanil 20 micrograms/kg, midazolam, and atracurium and maintained with nitrous oxide 70%, an alfentanil infusion (0.25 microgram.kg-1. min-1), and isoflurane. Anesthetic requirements, circulatory variables, interventions, and isoproterenol dose-response curves (pre- and postoperatively) were determined. Plasma concentrations of clonidine, alfentanil, and vasoactive hormones were measured. When the clonidine group was compared with the placebo group, (a) isoflurane, alfentanil, and midazolam requirements were reduced by 38%, 42%, and 41%, respectively (P = 0.04, 0.03, 0.0002, respectively); (b) supplemental circulatory and anesthetic adjustments were reduced by 51% (P = 0.0006); (c) interventions with vasopressors were not significantly increased (placebo: two; clonidine: five); (d) systolic and mean arterial pressures and heart rate were reduced; (e) increases in norepinephrine, epinephrine, and plasma renin activity were suppressed, whereas vasopressin surge was attenuated; and (f) chronotropic response to isoproterenol was unaffected. Clonidine was effective in reducing anesthetic requirements and in improving circulatory stability in hypertensive patients presenting for major vascular procedures.  相似文献   

3.
Retrospectively 78 patients with uni- or bilateral acute acoustic trauma (AAT) were evaluated to assess the therapeutic effect of hyperbaric oxygenation (HBO). All subjects received saline or dextran (Rheomacodrex) infusions with Ginkgo extracts (Tebonin) and prednisone. Thirty six patients underwent additional hyperbaric oxygenation at a pressure of 2 atmospheres absolute for 60 minutes once daily. Both treatment groups were comparable as far as age, gender, initial hearing loss and prednisone dose are concerned. The delay of therapy onset was 15 hours in both groups and treatment was started within 72 hours in all cases. Control audiometry was performed after 6.5 days, when the HBO group had had 5 exposures to hyperbaric oxygenation. The average hearing gain in the group without HBO was 74.3 dB and in the group treated additionally with HBO 121.3 dB (P < 0.004). It is concluded, that hyperbaric oxygenation significantly improves hearing recovery after AAT. Therefore acute acoustic trauma with significant hearing threshold depression remains an otological emergency. Minimal therapy involving waiting for spontaneous recovery, which is mostly incomplete leaving a residual C5 or C6 and handicapping tinnitus, is not the treatment of choice. Randomized prospective clinical trials with a larger patient series are needed and further experimental studies are required to understand the physiological mechanisms of HBO responsible for the clinical success in AAT.  相似文献   

4.
Approximately 2000 children aged between 0 and 14 years die annually of accidents and their sequelae in Japan. Moreover, accidents and their sequelae are the leading cause of death in the 1-4 year, 5-9 year and 10-14 year age groups. Accidental drowning and traffic accidents account for 2/3 of all such deaths. Measures for preventing injury in these age groups are clearly necessary, since the mortality rate due to accidents and their sequelae in children 0 to 4 years old is higher in Japan than in European countries. It is considered that the lives of 824 infants aged between 0 and 4 years might be saved annually in Japan if the mortality rate could be reduced to a level comparable to that in Sweden by accident prevention and control. Therefore, a systematic approach for prevention of childhood injury is a high priority in Japan.  相似文献   

5.
Analysis of germinal centers (GCs) in chronically inflamed human tonsils has led to the dogma that GCs contain two compartments with separate functions: a dark zone where B cells proliferate and hypermutate; and a light zone where selection and differentiation occur. However, here Stephanie Camacho and colleagues discuss immunohistological analysis of splenic GCs arising de novo that reveal a more plastic structure.  相似文献   

6.
In this study the efficacy and safety of short-term cilazapril administration on renal haemodynamics were evaluated in mild to moderate hypertensive subjects. Our final goal was to evaluate whether the reduction in blood pressure achieved by treatment was associated with maintained renal function. After a run-in period with placebo, 40 hypertensive subjects without renal or cardiac diseases were randomly allocated to a double-blind 4 week controlled trial with cilazapril 5 mg once a day (20 patients) or hydrochlorothiazide 25 mg once a day (20 patients). Renal haemodynamics measurements included effective renal plasma flow (ERPF) and glomerular filtration rate (GFR) by radionuclide study using 131I-hippuran and 99mTc, according to the methods described by Schlegel and Gates, respectively. Effective renal blood flow [ERBF = ERPF/(1-Ht)], filtration fraction (FF = GFR/ERPF) and renal vascular resistance (RVR = MBP x 80/ERBF) were calculated. At the end of cilazapril and hydrochlorothiazide administration significant decreases (p < 0.001) in SBP, DBP and MBP vs baseline values were observed. In the cilazapril group a significant decrease (p < 0.001) in RVR and FF and a significant increase (p < 0.001) in ERPF and ERBF were also found. In the hydrochlorothiazide group a significant decrease (p < 0.001) in RVR was found. No important side effects were observed with either treatment. In conclusion our data indicate that both cilazapril and hydrochlorothiazide reduced blood pressure equally well but only cilazapril improved renal blood flow and reduced filtration fraction.  相似文献   

7.
OBJECTIVES: This study was designed to evaluate the effect of carvedilol on nitrate tolerance in patients with chronic heart failure. BACKGROUND: The attenuation of cyclic guanosine 5'-monophosphate (cGMP) production due to inactivation of guanylate cyclase by increased superoxide has been reported as a mechanism of nitrate tolerance. Carvedilol has been known to combine alpha/beta-blockade with antioxidant properties. METHODS: To evaluate the effect of carvedilol on nitrate tolerance, 40 patients with chronic heart failure were randomized to four groups that received either carvedilol (2.5 mg once a day [carvedilol group, n=10]), metoprolol (30 mg once a day [metoprolol group, n=10]), doxazosin (0.5 mg once a day [doxazosin group, n=10]) or placebo (placebo group, n=10). Vasodilatory response to nitroglycerin (NTG) was assessed with forearm plethysmography by measuring the change in forearm blood flow (FBF) before and 5 min after sublingual administration of 0.3 mg NTG, and at the same time blood samples were taken from veins on the opposite side to measure platelet cGMP. Plethysmography and blood sampling were obtained serially at baseline (day 0); 3 days after carvedilol, metoprolol, doxazosin or placebo administration (day 3); and 3 days after application of a 10-mg/24-h NTG tape concomitantly with carvedilol, metoprolol, doxazosin or placebo (day 6). RESULTS: There was no significant difference in the response of FBF (%FBF) and cGMP (%cGMP) to sublingual NTG on day 0 and day 3 among the four groups. On day 6, %FBF and %cGMP were significantly lower in the metoprolol, doxazosin and placebo groups than on day 0 and day 3, but these parameters in the carvedilol group were maintained. CONCLUSIONS: These results indicated that carvedilol may prevent nitrate tolerance in patients with chronic heart failure during continuous therapy with NTG.  相似文献   

8.
Mitogen-activated protein kinase (MAPK) is a serine-threonine kinase that is activated by various extracellular stimuli. Extracellular signal-regulated kinases (ERK1 and ERK2), an MAPK subfamily, are activated by many oncogenes, such as ras and raf, and they induce cell proliferation. myc is also an oncogene and one of the targets of ERKs. Mutations of ras and overexpression of myc were found in various human cancers, and ERKs were also reported to play a role in carcinogenesis. In this study, we examined 39 biopsy specimens of oral squamous cell carcinoma (OSCC) and 5 of normal gingival mucosa for the expression of ERK protein and the proliferation marker, MIB-1 (Ki-67 antibody). Thirteen OSCC specimens and five normal gingival biopsies were also examined for the expression of ERKs mRNA by in situ hybridization. Double staining for ERKs and MIB-1 was also performed. Histologically, 18 patients (46%) were diagnosed with well-differentiated SCC, 17 (44%) with moderately differentiated SCC, and 4 (10%) with poorly differentiated SCC. The histologic grade correlated with the MIB-1 index. The localization of ERK1 was similar to that of ERK2. Positive signals for ERK proteins were localized in superficial keratinocytes in normal gingival mucosa, whereas these mRNAs were weakly positive in the basal and spinous layer. Basal and suprabasal cells were positive for MIB-1. In well-differentiated and moderately differentiated OSCC, positive signals for ERK mRNA and proteins were found at higher levels than in normal gingival mucosa in keratotic cells around cancer pearls. Some cells showed positive signals for ERKs and MIB-1. Furthermore, most cancer cells in poorly differentiated SCC were positive for both ERK and MIB-1. The histologic grade was statistically related to the percentage of cells positive for both ERK and MIB-1. This suggested that ERKs might be related to proliferation in OSCC.  相似文献   

9.
10.
BACKGROUND: Parenteral heparin is the anticoagulant of choice in hospitalized patients. Continued anticoagulation is achieved by subcutaneous administration of low-molecular-weight heparin or with an orally active anticoagulant such as warfarin. An oral heparin formulation would avoid the inconvenience of subcutaneous injection and the unfavorable drug interactions and adverse events associated with warfarin. A candidate delivery agent, sodium N-[8(-2-hydroxybenzoyl)amino]caprylate (SNAC), was evaluated with escalating oral heparin doses in a randomized, double-blind, controlled clinical study for safety, tolerability, and effects on indexes of anticoagulation. METHODS AND RESULTS: Increases in activated partial thromboplastin time (aPTT), anti-factors IIa and Xa, and tissue factor pathway inhibitor (TFPI) concentrations were detected when normal volunteers were dosed with 10.5 g SNAC/20000 IU heparin by gavage in some subjects. For the entire group, 30000 IU SNAC and heparin elevated TFPI from 74.9+/-7.6 to 254.2+/-12.3 mg/mL (P<0.001) 1 hour after dosing (P<0.001). Similar changes occurred in anti-factor IIa and anti-factor Xa. aPTT rose from 28+/-0.5 to 42.2+/-6.3 seconds 2 hours after dosing (P<0.01). No significant changes in vital signs, physical examination, ECGs, or clinical laboratory values were observed. Neither 30000 IU heparin alone nor 10.5 g SNAC alone altered the hemostatic parameters. Emesis was associated with 10.5 g SNAC. A taste-masked preparation of SNAC 2.25 g was administered orally with heparin 30000 to 150000 IU. Both aPTT and anti-factor Xa increased with escalating doses of heparin. This preparation was well tolerated. Conclusions-Heparin, administered orally in combination with the delivery agent SNAC, produces significant elevations in 4 indexes of anticoagulant effect in healthy human volunteers. These results establish the feasibility of oral delivery of anticoagulant doses of heparin in humans and may have broader implications for the absorption of macromolecules.  相似文献   

11.
A 49-year-old patient suffered from a binocular perforating trauma with metal foreign bodies in 1974. During an MRI examination in 1992 for a lumbar spine herniation a metal foreign body was mobilised from the deeper vitreal and retinal area, now causing optical disturbances freely floating in the anterior vitreous. Refusing an operation, the patient, an electrical engineer, tried himself to remove the foreign body out of the optical axis by exposing his head to the electro-magnetic field of an induction coil (pulsed magnetic induction B at t0 of 0.26 Tesla). The foreign body was split into multiple small parts no longer disturbing the patient. To early detect a siderosis regular ophthalmological controls including ERG are necessary. This example stresses that even small intraocular metal foreign bodies are a contraindication for the usually applied field strength of MRI examinations.  相似文献   

12.
An analytical study of the renin-angiotensin-aldosterone system was made in 124 individuals with essential hypertension, aged from 25 to 55 years. The results obtained, with rigorous control to posture and sodium balance, indicate the existence of a number of subgroups of hypertensive subjects related to their renin activity and plasma aldosterone in the upright position. This classification thus makes possible comparison with patients suffering from secondary hypertension.  相似文献   

13.
The possibility that there is an inhibitory component to auditory covert orienting was addressed. Each trial consisted of a cue followed by a target, and listeners were required to detect, localize, or identify the frequency of the target. At 150-msec stimulus onset asynchrony (SOA), performance was best when stimuli sounded from the same location or were of the same frequency. However, at 750-msec SOA, performance was best when stimuli differed in location or were of different frequencies. These results document the existence of both location-based and frequency-based auditory inhibition of return.  相似文献   

14.
Behavioral adaptations exhibited by two African fossorial mammals for the reception of vibrational signals are discussed. The Namib Desert golden mole (Eremitalpa granti namibensis) is a functionally blind, nocturnal insectivore in the family Chrysochloridae that surface forages nightly in the Namib desert. Both geophone and microphone recordings in the substrate suggest that the golden mole is able to detect termite colonies and other prey items solely using seismic cues. This animal exhibits a hypertrophied malleus, an adaptation favoring detection of low-frequency signals. In a field study of the Cape mole-rat (Georychus capensis), a subterranean rodent in the family Bathyergidae, both seismic and auditory signals were tested for their propagation characteristics. This solitary animal is entirely fossorial and apparently communicates with its conspecifics by drumming its hind legs on the burrow floor. Auditory signals attenuate rapidly in the substrate, whereas vibratory signals generated in one burrow are easily detectable in neighboring burrows. The sensitivity to substrate vibrations in two orders of burrowing mammals suggests that this sense is likely to be widespread within this taxon and may serve as a neuroethological model for understanding the evolution of vibrational communication. Neuroethological implications of these findings are discussed.  相似文献   

15.
The antiarrhythmic effect of oral captopril was studied during the early (day 3) and late (day 14) phase of acute myocardial infarction among 304 patients in a randomized placebo-controlled substudy of ISIS-4. Ventricular arrhythmias (ventricular ectopic beats per hour) occurred significantly less frequently among captopril-allocated patients than among those allocated placebo at day 3 (logarithmic scale: 0.48 +/- 0.8 captopril vs 0.84 +/- 1.3 placebo; P < 0.003) and at day 14 (0.51 +/- 1.0 vs 0.77 +/- 1.3; P < 0.05). The number of patients with frequent ventricular arrhythmias (more than 10 ventricular ectopic beats per hour) was also significantly lower among those allocated captopril at day 3 (7.3% vs 14.4%; P < 0.05) and at day 14 (7.3% vs 14.8%; P < 0.05). These results support the hypothesis that the activation of the renin-angiotensin-aldosterone and sympathetic system may underlie heart rhythm disturbances in acute myocardial infarction, and that early use of converting enzyme inhibitor therapy may ameliorate these disturbances.  相似文献   

16.
BACKGROUND/AIMS: Silymarin has protective effects in different experimental conditions, but its efficacy in human liver cirrhosis has not been completely established. Therefore, this study was carried out to determine the effect of silymarin in alcoholics with liver cirrhosis with respect to survival and clinical and laboratory changes. METHODS: From February 1986 to June 1989, we enrolled 200 alcoholics with histologically or laparoscopically proven liver cirrhosis in a randomized, double-blind multicenter trial comparing 450 mg of silymarin (150 mg/ three times per day) with placebo. The primary outcome was time to death, and the secondary outcome was the progression of liver failure. Additional analyses were also performed in 75 patients in whom anti-hepatitis C virus antibodies were measured after completion of the trial. RESULTS: One hundred and three patients were assigned to receive silymarin and 97 to receive placebo. The two groups were well matched for demographic and baseline clinical and laboratory features. A 2-year study period was completed in 125 patients (57 receiving silymarin and 68 receiving placebo). Twenty-nine patients (15 receiving silymarin, and 14 receiving placebo) died during the trial. Survival was similar in patients receiving silymarin or placebo. The effect of silymarin on survival was not influenced by sex, the persistence of alcohol intake, the severity of liver dysfunction or by the presence of alcoholic hepatitis in the liver biopsy. Silymarin did not have any significant effect on the course of the disease. No relevant side-effects were observed in any group. CONCLUSIONS: The results of this study indicate that silymarin has no effect on survival and the clinical course in alcoholics with liver cirrhosis.  相似文献   

17.
OBJECTIVE: To describe the effect of infection control interventions on the incidence of vancomycin-resistant enterococci (VRE), the utility of pharyngeal cultures for surveillance for VRE colonization, and the cost of barrier precautions. DESIGN: Evaluation of the occurrence of VRE infection or colonization, rates of vancomycin use, results of surveillance cultures before and after interventions, and the cost of increased barrier precautions. SETTING: University of Massachusetts Medical Center, a 347-bed tertiary-care teaching hospital with eight intensive-care units, one burn unit, and one bone marrow transplant unit. PARTICIPANTS: Patients in the intensive-care units and staff who were involved with patients colonized or infected with VRE. METHODS: Infection control interventions included placement of patients with VRE in private rooms, strict contact isolation, cohorting of patient and nursing staff, prohibiting of equipment sharing, and monitoring of compliance with the vancomycin restriction policy, with hand washing, and of the adequacy of environmental cleaning. Both rectal and pharyngeal cultures were obtained from patients at the beginning of the outbreak, and the utility of pharyngeal cultures was evaluated. The cost of barrier precautions was estimated by comparing the cost of glove and gown use before and after the outbreak began. RESULTS: The interventions decreased the number of new cases of VRE, but total eradication of VRE was not achieved. Compliance with the room-cleaning protocol was 91% (141/155 observations). Hand washing following interaction with patients who were not in isolation was 51%, vs 100% for patients in isolation. Overall, handwashing compliance was 71% (319/449): 56% (130/231) for physicians and 86% (187/218) for nurses (P<.0001). The mean number of doses of vancomycin dispensed per 1,000 patient days decreased from 145 to 114 per 1,000 patient days (P<.001). Compliance with vancomycin-use guidelines was 85%. Forty-six (77%) of 60 surveillance rectal swabs yielded enterococci, as compared to only 4 (11%) of 36 pharyngeal cultures (P<.0001). Expenses on glove and gowns alone increased by over $11,000 per year since the epidemic began. CONCLUSIONS: Implementation of the various infection control measures did not eradicate VRE cases from the hospital. Rectal cultures were more useful than pharyngeal cultures for surveillance of VRE. Controlling VRE epidemics can be costly.  相似文献   

18.
PURPOSE: Ultrasound estimated bladder weight was compared before and after surgery for benign prostatic hyperplasia (BPH) to reveal a possible reversible change in bladder hypertrophy. MATERIALS AND METHODS: Ultrasound estimated bladder weight was measured before and after subcapsular (17) or transurethral (16) prostatectomy in 33 male patients with BPH. Sequential changes in the American Urological Association symptom score and urinary flow rate were also examined. RESULTS: Along with a significant improvement in the American Urological Association symptom scores and maximum flow rate, ultrasound estimated bladder weight decreased from 52.9 +/- 22.6 to 31.6 +/- 15.8 gm. in 12 weeks after treatment. In all but 4 patients (29 of 33, or 87.9%) ultrasound estimated bladder weight decreased to less than 35.0 gm. in 12 weeks after treatment. Interestingly, in all patients with an initial ultrasound estimated bladder weight of greater than 80 gm. the bladder weight still remained at an abnormally high level 12 weeks after treatment. CONCLUSIONS: Bladder hypertrophy was completely reversible after the surgical treatment of the obstruction in the majority of patients with BPH. The measurement of ultrasound estimated bladder weight was of value in monitoring therapeutic effects in BPH patients. An extraordinarily high ultrasound estimated bladder weight of 80 gm. or more might suggest degenerative and irreversible pathological changes in the bladder detrusor.  相似文献   

19.
In the present multicentre randomized phase II trial, the activity and toxicity of three platinum-based combination regimens for the treatment of advanced non-small-cell lung cancer (NSCLC) were evaluated. The three regimens were: MVP (mitomycin-C 6 mg m(-2) on day 1, vindesine 3 mg m(-2) on days 1 and 15, and cisplatin 80 mg m(-2) on day 1 every 28 days), PIN (cisplatin 80 mg m(-2) day 1, ifosfamide 3 g m(-2) day 1 and vinorelbine 25 mg m(-2) day 1 and 8 every 21 days) and CaN (carboplatin 350 mg m(-2) day 1 and vinorelbine 25 mg m(-2) days 1 and 8 every 28 days). A total of 140 chemotherapy-naive patients entered the study; 49 patients were treated with MVP, 48 with PIN and 43 with CaN. Sixty-seven per cent of the patients had stage IV disease. Response rates, calculated on an 'intention to treat' basis, were as follows: MVP, 14.3% (95% CI 5.94-27.2%); PIN, 16.7% (95% CI 7.4-30.2%); and CaN, 14% (95% CI 5.3-27.9%). The overall median survivals were 256, 269 and 243 days for patients treated with MVP, PIN and CaN respectively. Myelosuppression was the most frequent toxicity: grade 3-4 leucopenia was observed in 14.3%, 25% and 18.6% of patients treated with MVP, PIN and CaN respectively. This multicentre phase II randomized trial shows that MVP, PIN and CaN can be administered on an outpatient basis with acceptable toxicities. Unfortunately, the three regimens showed an activity significantly lower than that reported in previous single-institution phase II trials.  相似文献   

20.
The amounts of dynorphin-(1-8) [dyn-(1-8)] and its seven hydrolysis products, Y, YG, YGG, YGGF, YGGFL, YGGFLR and YGGFLRR, were estimated after incubating dyn-(1-8) with a membrane fraction from either guinea-pig ileum or striatum for various times at 37 degrees C. The major hydrolysis products during the initial 5-min incubation were YGGFLR and Y, which indicates that dipeptidyl carboxypeptidase and aminopeptidase activities were mainly involved in the hydrolysis. After 60 min of incubation, dyn-(1-8) was completely hydrolyzed in both membrane preparations. When the ileal and the striatal preparations were incubated for 60 min in the presence of both captopril, a dipeptidyl carboxypeptidase inhibitor, and amastatin, an aminopeptidase inhibitor, 63.8 and 49.3% of dyn-(1-8), respectively, were hydrolyzed. The YGG fragment was the major hydrolysis product in both preparations. When the ileal and the striatal membrane fractions were incubated with dyn-(1-8) in the presence of three peptidase inhibitors, captopril, amastatin and phosphoramidon (an inhibitor of endopeptidase-24.11), approximately 95% of the opioid octapeptide remained intact in both cases. This shows that dyn-(1-8) was almost exclusively hydrolyzed by three enzymes, amastatin-sensitive aminopeptidase, captopril-sensitive dipeptidyl carboxypeptidase I and phosphoramidon-sensitive endopeptidase-24.11, in both ileal and striatal membranes. Additionally, the Ke (equilibrium dissociation constant) values of selective antagonists against dyn-(1-8) and its initial main hydrolysis product YGGFLR in two isolated preparations pretreated with the three peptidase inhibitors indicate that the latter acts on mu receptors in guinea pig ileum but delta receptors in mouse vas deferens and the former acts on kappa receptors in both preparations. It is indicated, therefore, that in the absence of peptidase inhibitors endogenously released dyn-(1-8) acts either through dyn-(1-8) itself on kappa receptors or through YGGFLR on mu or delta receptors depending on both the three peptidase activities and the three receptor type densities at the target synaptic membrane.  相似文献   

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