Renal nerve stimulation restores tubuloglomerular feedback after acute renal denervation

Renal nerves play an important role in the setting of the sensitivity of the tubuloglomerular feedback (TGF) mechanism. We recently reported a time-dependent resetting of TGF to a lower sensitivity 3–4 h after acute unilateral renal denervation (aDNX). This effect persisted after 1 week, but was then less pronounced. To determine whether normal TGF sensitivity could be restored in aDNX kidneys by low-frequency renal nerve stimulation (RNS), the following experiments were performed. Rats with aDNX were prepared for micropuncture. In one experimental group proximal tubular free flow (P_t) and stop flow pressures (P_sf) were measured during RNS at frequencies of 2, 4 and 6 Hz. In another series of experiments the TGF sensitivity was evaluated from the P_sf responses at different loop perfusion rates after 20 min of RNS at a frequency of 2 Hz. The maximal drop in P_sf (ΔP_sf) and the tubular flow rate at which half the maximal response in ΔP_sf was observed (turning point, TP), were recorded. At RNS frequencies of 2, 4 and 6 Hz, P_t decreased from the control level of 14.1 ± 0.8–13.1 ± 1.0, 12.4 ± 1.1 and 11.2 ± 0.8 mmHg (decrease 21%, P < 0.05), respectively, while at zero perfusion and during RNS at 2 and 4 Hz P_sf decreased from 42.5 ± 1.6 to 38.2 ± 1.4 and 32.8 ± 4.3 mmHg (decrease 23%, P < 0.05), respectively. The TGF characteristics were found to be reset from the normal sensitivity with TP of 19.0 ± 1.1 nL min^–1 and ΔP_sf of 8.7 ± 0.9 mmHg to TP of 28.3 ± 2.4 nL min^–1 (increase 49%, P < 0.05) and ΔP_sf of 5.8 ± 1.2 mmHg (decrease 33%) after aDNX. After 20 min of RNS at 2 Hz TP was normalized and ΔP_sf was 33% higher. Thus the present findings indicate that the resetting of the TGF sensitivity that occurred 2–3 h after aDNX could be partially restored by 20 min of RNS at a frequency of 2 Hz. These results imply that renal nerves have an important impact on the setting of the sensitivity of the TGF mechanism.     

Effect of denervation of the working capacity of muscles

In acute experiments on cats, the working capacity of the leg muscles during stimulation of the sciatic nerve was increased after division of the sciatic and femoral nerves. This effect was not due to changes in the circulation, for it persisted if the blood flow was stabilized. Increased working capacity was also manifested after partial deafferentation of the limb by division of the dorsal roots of the spinal cord or extirpation of the tibial bone marrow.Laboratory of Experimental Physiology, Latvian Research Institute of Experimental and Clinical Medicine, Riga. (Presented by Academician V. N. Chernigovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 79, No. 2, pp. 6–8, February, 1975.     

Time course of changes in EMG activity of fast muscles after partial denervation

After partial denervation, the remaining motor units (MUs) of adult fast extensor digitorum longus muscle (EDL) expand their peripheral field. The time course of this event was studied using tension measurement and recordings of electromyographic (EMG) activity. The results show that after section of the L4 spinal nerve, when only 5.3 ± 0.63 of the 40 MUs normally supplying EDL muscle remain, the force of individual motor units starts to increase between the 1st and 2nd week after the operation and continues to do so for a further week. The drastic reduction of the number of motoneurones supplying the fast EDL leads to an increase in activity of the remaining MUs. In the 1st week after partial denervation, there was a sharp increase in the EMG activity of remaining motor units. During the next 12 days, this increase became less marked, but EMG activity remained nevertheless significantly higher than that of the unoperated EDL muscle. Many MUs became tonically active during posture. The EMG activity pattern during locomotion was also altered, so that the burst duration was positively correlated with the step cycle duration. Moreover, shortly after partial denervation, the interlimb coordination was disturbed but returned to its original symmetrical use 1–2 weeks later. Received: 17 September 1996 / Accepted: 3 November 1997     

Lysosomal and energy enzyme activities in hypertrophied rat soleus muscle after denervation

Muscle hypertrophy was induced in the soleus muscle of young rats by tenotomy of the gastrocnemius and plantaris muscles. Three and 7 days afterwards the sciatic nerve was sectioned. The loss of weight of muscles subjected to this combined procedure three days after denervation was 30–40%. Lysosomal enzyme activities (acid phosphatase, -glucosidase, -galactosidase and N-acetyl--d-glucosaminidase) and energy enzyme activities (lactate dehydrogenase, LDH, triose-3-phosphate dehydrogenase, TPDH,d-hexokinase, HK and citrate synthase, CS) were determined 3 days after denervation, 3, 7 and 10 days after hypertrophy had been induced and 3 days after denervation of hypertrophying muscles on day 3 and 7. Normal non-operated rats of corresponding body wieght served as controls and their enzyme activities were estimated on the same day. In the course of muscle hypertrophy, the 4 lysosomal enzyme activities increased progressively. Although 3 days' denervation of control muscles did not alter lysomal enzyme activities, denervation of hypertrophying muscles greatly enhanced the activity of these enzymes. Enzymes of energy metabolism were affected to a lesser degree. The results suggest that denervation of hypertrophying muscles causes more extreme changes in muscle weight and lysosomal enzyme activities than denervation alone. The possible implications of this finding are discussed in relation to the rapid atrophy.     

去窦弓神经大鼠的心血管及肾脏的形态学改变(英文)

目的　研究去窦弓神经 (SAD)对正常血压大鼠的血流动力学及心、肾、血管等器官病理形态学的影响。方法　采用SD大鼠施行SAD手术 ,术后 18周行股动脉插管 ,在清醒、自由活动状态下计算机实时记录 2 4h动脉收缩压、舒张压和心率 ,并计算血压波动性 (BPV)和心率波动性 (HRV)。处死动物后 ,取心、脑、肾及脾观察大体及光学显微镜下结构变化。结果　SAD术后 18周 ,SAD大鼠的血压和心率水平与假手术组相比无显著差异 ,但 2 4hBPV明显高于假手术组 ,HRV明显低于假手术组 ;大鼠心、肾及血管有明显的类似于高血压靶器官损伤的病理改变。结论　SAD可使大鼠的心、肾和血管发生类似于高血压靶器官损伤的病理改变。     

肾交感神经射频消融术与顽固性高血压的治疗

高血压是最常见的慢性病。也是心血管疾病最重要的危险因素之一。当前我国高血压患者总体控制率明显较低,约为10％,其原因很多,其中顽固性高血压或称难治性高血压是重要原因之一。顽固性高血压是一种特殊类型的高血压,常伴有较严重的靶器官损害和高发心血管疾病风险．     

高血压犬经导管射频消融去肾交感神经术后血压及神经损伤因子的变化

目的：对高血压犬采用经导管射频消融去肾交感神经术验证其降压疗效,并检测术后神经损伤因子血浆
S-100B及神经元特异性烯醇化酶(NSE)含量以探讨其与肾交感神经损伤的关系。方法：12条比格犬随机分为手术组
(n=6)和假手术组(n=6)。采用高脂饮食建立高血压模型,手术组实施经导管射频消融去肾交感神经术,假手术组仅行
肾动脉造影。观察血压变化,分别在术前和术后第3天、1周、2周、1个月、2个月、3个月监测血压并检测血浆S-100B
和NSE的浓度。结果：建模后,手术组及假手术组收缩压(SBP)、舒张压(DBP)、平均动脉压(MBP)较基线均有显著上
升(P<0.05)。经导管射频消融去肾交感神经术后,手术组术后1个月及3个月较假手术组SBP,DBP,MBP均有显著下
降(P<0.05);术后3个月复查血肌酐正常,复查肾动脉造影未发现肾动脉狭窄。经导管射频消融去肾交感神经术后第3
天、1周及2周手术组较假手术组血浆S-100B或NSE的含量升高(P<0.05)。结论：经导管射频消融去肾交感神经术可以
显著和持久地降低高血压犬的SBP,DBP及MBP。经导管射频消融去肾交感神经术后S-100B及NSE血浆含量可能作为
评估高血压犬肾交感神经损伤的指标。     

去肾交感神经术对自发性高血压大鼠肾胺酶及酪氨酸羟化酶的影响

目的:通过观察自发性高血压大鼠（SHR）去肾交感神经手术前后血压、肾胺酶浓度、肾脏酪氨酸羟化酶（TH）与肾胺酶表达水平的变化,探讨去肾交感神经术降低血压的可能机制。方法:将SHR 大鼠（n=48）随机分为基线组、手术组、假手术组和对照组,同批同周龄WKY 大鼠（n=12）作为基线对照组,同条件喂养至12 周龄测各组血压,首批处死SHR 基线组、WKY 组,采血、取肾脏组织送检;手术组、假手术组与对照组继续监测血压,于去肾交感神经术后1,6 周时分批处死每组大鼠各6 只,分别采血、取肾脏组织送检。采用ELISA 方法测定血浆肾胺酶浓度,Western 印迹测定肾脏TH、肾胺酶蛋白表达水平。结果:与WKY 组大鼠比较,SHR 基线组大鼠血压、肾脏TH 蛋白表达水平明显升高（P<0.05),血浆肾胺酶浓度及蛋白表达水平明显下降(P<0.05);术后1 周,手术组大鼠平均动脉压与TH 蛋白表达水平较基线组明显降低且明显低于假手术组及对照组(P<0.05),手术组肾胺酶水平较基线组明显增高并明显高于假手术组及对照组(P<0.05);术后6 周,手术组平均动脉压与TH 水平较术后1 周上升而肾胺酶浓度及水平较术后1 周降低,较基线组、假手术组与对照组差异无统计学意义(P>0.05);假手术组与对照组较基线组各项指标差异无统计学意义(P>0.05)。结论:去肾交感神经术降低血压的作用可能与其抑制交感神经,升高肾胺酶浓度及其蛋白表达水平有关。     

An update of the expert consensus statement of the Czech Hypertension Society on renal denervation in resistant hypertension

In the spring of 2012, the Czech Society of Cardiology and Czech Hypertension Society issued a joint expert consensus statement on catheter-based renal denervation (RDN) in the Czech Republic. On the basis of new information from the Symplicity HTN-3, PRAGUE-15 and other studies, there is no reason to introduce RDN into clinical practice. New modalities for RDN, such as radiofrequency ablation, are investigated.