Stimulation of locus coeruleus increases arterial pressure in rabbits

目的：研究电刺激和化学刺激兔蓝斑（ＬＣ）对动脉血压（ＡＰ）和肾交感神经传出活动（ＲＳＡ）的影响．方法：电刺激ＬＣ，ＬＣ微量注射ＬＧｌｕ、盐酸吗啡、ＧＡＢＡ、电解毁损ＬＣ，记录ＡＰ和ＲＳＡ．结果：电刺激ＬＣ和ＬＣ注射ＬＧｌｕ均引起ＡＰ升高（分别为１３５±０３ｖｓ１９５±０８ｋＰａ和１３８±０４ｖｓ１７５±０８ｋＰａ）和ＲＳＡ增加．ＬＣ注射吗啡、ＧＡＢＡ对ＡＰ和ＲＳＡ无明显影响．电解毁损ＬＣ后电刺激ＬＣ区、ＬＣ区注射ＬＧｌｕ对ＡＰ和ＲＳＡ无明显影响．结论：兔ＬＣ兴奋引起ＡＰ升高和ＲＳＡ增加，但ＬＣ不是ＡＰ和ＲＳＡ的紧张性中枢．     

红霉素对犬幽门括约肌压力影响及其与胃动素,生长抑素的关系

为探讨红霉素对犬幽门括约肌的作用及其机理，及其与血浆胃动素，生长抑素的关系。方法采用胃压力测量仪及放射免疫法，同步监测观察了１０条犬静脉滴ＥＭ前后和使用拮抗剂后的幽门压力、血浆ＭＴＬ，ＳＳ的变化，结论：ＥＭ具有增高犬胃幽门压力的作用，其作用机理除与血浆ＭＴＬ有着密切的关系外，血浆ＳＳ也可能共同参与了其调节机制。     

血压在前阻力血管中下降最快的原因分析

目的：解释血压在毛细血管前阻力血管中下降最快的原因。方法：利用物理模型简化复杂的心血管系统。结果：全身所有的微、小动脉段“并联”，全身所有的毛细血管段“并联”。结论：微、小动脉段的总流阻最大、使俐血压在微、小动脉中下降最快。     

EFFECT OF CROSS-FOSTERING ON NEONATAL SODIUM BALANCE AND ADULT BLOOD PRESSURE IN THE SPONTANEOUSLY HYPERTENSIVE RAT

1. The aim of the present study was to compare electrolyte handling in naturally reared neonatal spontaneously hypertensive rats (SHR) with those reared by a Wistar-Kyoto (WKY) rat foster mother (denoted SHRX), as cross-fostering SHR pups to a WKY rat dam lowers adult blood pressure in the SHR. 2. The electrolyte content of WKY rat and SHR dams’ milk was determined and electrolyte intake and urinary excretion rates were calculated in both naturally reared and cross-fostered WKY rat and SHR pups. 3. The milk sodium concentration fell in both strains (WKY rat: 31.8 ± 2.0 to 15.2 ± 1.2 mmol/L; SHR 31.9 ± 2.5 to 18.2 ± 1.6 mmol/L; P < 0.001), as did potassium (P < 0.001), over lactation, but there were no differences between strains. Calcium and magnesium concentrations increased (P< 0.001), although SHR dam's milk contained less calcium (P < 0.001) than that of WKY rat dams during the third week of lactation. 4. Spontaneously hypertensive rat pups ingested less milk (P<0.05) than WKY rat pups; therefore, their cumulative sodium intake over postnatal days 4–15 was significantly lower than that of WKY rat pups (WKY rat vs SHR: 84.4 ± 3.6 vs 59.7 ± 2.6 μmol/g bodyweight, respectively; P < 0.05) and fostered SHRX pups (77.7 ± 7.0 μmol/g bodyweight; P < 0.05). Potassium and magnesium intakes were comparable between SHR, WKY rat and SHRX pups, but SHR pups ingested significantly less calcium than either WKY rat pups (136.1 ± 6.4 vs 200.1 ± 9.5p, mol/g bodyweight, respectively; P<0.05) or SHRX pups (200.0 ± 18.0 μmol/g bodyweight; P<0.05). 5. These data show that the neonatal SHR experiences a period of sodium deficiency during the developmental stage when cross-fostering is effective in lowering blood pressure. This is consistent with the reported up-regulation of the renin-angiotensin system observed in SHR at this time and may have a long-term influence on blood pressure.     

THE EFFECT OF HYPERTENSIVE EPISODES AND CARDIAC HYPERTROPHY ON THE CANINE CARDIAC BAROREFLEX

1. Left ventricular (LV) hypertrophy has been implicated in the reduction of baroreflex sensitivity present in hypertension. The aim of the current study was to investigate the mean arterial pressure-heart rate reflex (MAP-HR) in a model which induced left ventricular hypertrophy but no sustained blood pressure elevation. 2. Five mongrel dogs were exposed to transient blood pressure elevation of between 20 and 30 mmHg, through hindlimb compression using a pneumatic pressure suit, for 7 h per day, 6 days per week for 6 weeks. Resting blood pressure was not altered by the 6 week hindlimb compression intervention. 3. Echocardiographically determined LV mass (mean ± s.e.m.) was 116.0 ± 7.4 g prior to hindlimb compression (baseline) and elevated to 125.4 ± 8.1 g (P= 0.003) after 6 weeks of compression. A reduction in the early (E) to late (A) transmitral diastolic flow ratio (E/A) from 1.80 ± 0.06 at baseline to 1.54 ± 0.09 (P = 0.037) after the 6 week intervention suggested that cardiac compliance was reduced. 4. The maximum gain of the MAP-HR reflex, studied using the ‘steady-state’ drug technique, when blood pressure was normal, showed a trend for reduction from 3.85 ± 0.43 beats/min per mmHg at baseline to 3.10 ± 0.45 beats/min per mmHg (P= 0.067) after 6 weeks of compression. This gain reduction became significant after β-adrenoceptor blockade with propranolol (3.13 ± 0.55 vs 2.32 ± 0.25 beats/min per mmHg; P= 0.039). Covariant analysis showed a significant inverse correlation between LV mass and maximum gain (r= 0.96; P<0.001) during the 6 week compression period. 5. The MAP-HR reflex changes in this model mimic those present in hypertension and implicate cardiac hypertrophy as one possible mediator.     

THE INFLUENCE OF CAPTOPRIL AND NALOXONE ON THE VALSALVA MANOEUVRE AND SYSTOLIC TIME INTERVALS IN HEALTHY VOLUNTEERS

1. The aim of the study was to ascertain whether the inhibition of the sympathetic nervous system by angiotensin-converting enzyme (ACE) inhibitors is mediated by endogenous opioids. Naloxone was used to evaluate the effects of the latter on systolic time intervals (STI) and Valsalva manoeuvre-induced blood pressure and heart rate changes. 2. Baseline recordings were done in 12 healthy male volunteers and repeated 2h after oral administration of 75 mg of captopril and again after naloxone 0.4 mg/kg was administered intravenously over 10 min. 3. After captopril there was a significant reduction in systolic (P<0.02) and mean blood pressure (P<0.04) without any changes in heart rate. Furthermore, captopril increased the Valsalva ratio (P<0.06) but did not influence inotropism as indicated by STI. Naloxone did not influence any of these findings. 4. The changes in the Valsalva ratio after captopril were mediated by an increase in the maximum bradycardia in nine of the 12 subjects. 5. The results indicate that endogenous opioids do not play a role in the putative sympatholytic effect of ACE inhibition.     

正常腹内压影响因素的临床研究

目的　探讨正常腹内压的影响因素 ,建立腹内压回归方程。方法　应用膀胱测压法测定 10 6例住院患者的腹内压 ,并对年龄、性别、身高、体重、体质指数、既往和近期腹部手术史、住院原因、合并症情况及数量等 14项因子与腹内压的关系进行分析。结果　住院患者平均腹内压为 5 .5mmHg( 1mmHg =0 .133kPa) ,范围为 0 .4～12 .8mmHg。各级体质指数相应的腹内压差异有显著性意义 (F =5 .5 5 0 ,P<0 .0 1)。男性腹内压比女性高 2 .0mmHg ,差异有显著性意义 (t=3.12 2 ,P<0 .0 1)。其他 12种因素对腹内压无明显影响 (P>0 .0 5 )。结论　正常腹内压可能受性别和体质指数影响 ,存在明显的个体差异