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Biomedical subjects

E Wiedemann

Publications and source records attributed to E Wiedemann.

At least 37 records · Page 2Linked to original sources
PubMed1998

Prevention of reflex natriuresis after acute unilateral nephrectomy by melanocortin receptor antagonists.

gamma-Melanocyte-stimulating hormone (gamma-MSH), atrial natriuretic peptide (ANP), and oxytocin have been identified as candidate hormonal mediators of the reflex natriuresis that follows acute unilateral nephrectomy (AUN). Pharmacological characterization of the third melanocortin receptor (MC3-R) indicates that it uniquely responds to physiological concentrations of gamma-MSH. We tested the roles of gamma-MSH, ANP, and oxytocin in the postnephrectomy natriuresis by carrying out AUN during continuous intrarenal infusion of specific antagonists for their cognate receptors. In anesthetized Sprague-Dawley rats, urinary sodium excretion (UNaV) increased from 0.34 +/- 0.04 to 1.12 +/- 0.11 mu eq/min 90 min after AUN (P < 0.001). No change in UNaV occurred in rats undergoing a sham AUN procedure. Plasma immunoreactive gamma-MSH concentration was 53 +/- 8 fmol/ml after sham AUN but 112 +/- 17 fmol/ml after AUN (P < 0.01). SHU-9119 and SHU-9005 are substituted derivatives of alpha-MSH with potent antagonism at the MC3-R in vitro. Infusion of these compounds at 5 pmol/min completely blocked the natriuretic response to AUN despite a similar elevation in plasma gamma-MSH (111 +/- 12 vs. 49 +/- 8 fmol/ml in sham rats, P < 0.01). Intrarenal infusion of the ANP receptor antagonist A-71915 (5 pmol/min) or the oxytocin receptor antagonist [d(CH2)(5)1, Tyr(Me)2,Orn8] vasotocin (10 pmol/min) effectively inhibited the natriuresis induced by intravenous infusion of ANP or oxytocin (each at 1 pmol/min), respectively, but did not block the natriuresis after AUN. Plasma immunoreactivity of these peptides was not increased after AUN. These results indicate that reflex natriuresis after AUN is accompanied by an increase in plasma gamma-MSH but not ANP or oxytocin concentration and is prevented by intrarenal infusion of receptor antagonists with selectivity for MC3-R. The data indicate that gamma-MSH or a closely related peptide mediates postnephrectomy natriuresis and provide further support for the possibility that gamma-MSH may play a wider role in sodium homeostasis.

Animals↗
PubMed1998

Prospective evaluation of MR arthrography performed with high-volume intraarticular saline enhancement in patients with recurrent anterior dislocations of the shoulder.

OBJECTIVE: The purpose of this study was to evaluate the accuracy of high-volume saline-enhanced MR arthrography in assessing the labrum, the ligaments, and the bony components of the glenohumeral joint. SUBJECTS AND METHODS: Forty-four patients with recurrent anterior dislocations of the shoulder underwent MR arthrography after intraarticular injection of 15-40 ml of saline solution. Two-dimensional fast low-angle shot and T1-weighted spin-echo sequences were prospectively evaluated by two observers. Anterior (Bankart) lesions, superior labral lesions extending from anterior to posterior, and Hill-Sachs lesions were diagnosed. Glenohumeral ligaments (GHLs) were identified and classified using a standard system. MR imaging results were compared with those of arthroscopy (n = 32) or open surgery (n = 12), either of which was the gold standard. RESULTS: Bankart lesions and superior labral lesions extending from anterior to posterior were revealed with a sensitivity of 93% and 89%, respectively, and a specificity of 80% and 89%, respectively. Diagnostic accuracy was 89% for both types of lesions. All six patients with bony Bankart lesions had high fat-marrow signal intensity within the fragment on T1-weighted MR images. For GHLs, MR imaging results and arthroscopy correlated in 25 of the 31 patients. In three patients all three GHLs were visible on MR imaging, but only two GHLs were detected with arthroscopy. In three patients two GHLs were detected on MR imaging but all three were visible on arthroscopy. Hill-Sachs lesions were revealed with a sensitivity of 95%, a specificity of 50%, and an accuracy of 81%. CONCLUSION: High-volume saline-enhanced MR arthrography is accurate in revealing the labrum, the ligaments, and the bony components of the glenohumeral joint Saline solution is inert and inexpensive, two advantages over gadopentetate dimeglumine.

Adult↗
PubMed1997

[Dislocated multiple fragment fractures of the head of the humerus. Does dislocation of the humeral head fragment signify a worse prognosis?].

PROBLEM: The vascularity of the articular fragment is of key importance for the final outcome in three- and four-part fractures of the humeral head. Displacement of the articular segment may compromise the arterial blood supply to the humeral head and result in avascular necrosis. There is still controversy as to whether three-and four-part fracture dislocations (articular fragment outside the glenoid) have an even worse prognosis than displaced three- and four-part fractures. PATIENTS AND METHODS: Between January 1985 and May 1993, 102 patients with three- and four-part fractures of the humeral head were treated by ORIF (mostly tension band wiring) at our institution. In a retrospective study we analysed the functional (Constant 100 point score) and radiological outcome of 67 (66%) of these patients. There were 21 patients with fracture dislocations (FD), n = 5 type B2X, n = 5 type B3X, n = 3 type C2X, n = 8 type C3X, according to the classification of Habermeyer [7]. The "X" represents the dislocation of the articular fragment, whereas the classification to each type is done after reduction of the head. The remaining 46 patients presented with displaced, but not dislocated, three- and four-part fractures (DF), n = 24 type B2, n = 7 type B3, n = 3 type C2, n = 12 type C3. Average follow-up was 25 months (7-72 months). Patients with FD were significantly younger (average age 50 years) than patients with DF (average age 63 years, P < 0.05) and showed a significantly higher incidence of traumatic nerve or plexus lesions (FD 19%, DF 2%, P < 0.05). RESULTS: Concerning the functional results, there was no statistically significant difference between the two groups. The FD patients even showed a slight tendency to better results than patients with DF. This was true for the three-part fractures (average Constant score 78 versus 67 points), as well as for the four-part fractures (average Constant score 62 versus 55 points). The significantly younger age of the FD patients may explain their better results. The entire group of patients with three-part fractures showed a significantly better functional outcome (average Constant score 68 points) than patients with four-part fractures (average Constant score 55 points, P < 0.05). The rate of partial and total avascular necrosis of the humeral head was strongly correlated to the fracture type (number of fragments, fracture of the anatomical or surgical neck, according to the classification of Habermeyer),but again there was no difference between the FD and DF group (B2X: 20%, B3X: 20%, C2X: 33%, C3X: 63%; B2: 25%, B3: 29%, C2: 33%, C3: 67%). Astonishingly, the FD were not associated with an increased rate of avascular necrosis of the humeral head. Three (axillary nerve) out of the five observed primary nerve and plexus lesions had a full neurological recovery after 6-12 months; the two patients with alterations of the brachial plexus showed a slow tendency of improvement at follow-up (12 and 18 months), but still had gross muscular atrophy and impaired sensory function. CONCLUSION: In displaced three-and four-part fractures of the humeral head the dislocation of the articular segment does not seem to increase the risk of avascular necrosis, if treated by timely and careful ORIF with respect to the vascularity. Even with the increased risk of primary nerve and plexus lesions in fracture dislocations, good functional results can be achieved by early operative nerve decompression and fracture stabilization in this middle-aged patient group. However, older patients with displaced or dislocated four-fragment fractures through the anatomical neck (type C3) have a poor chance of a favourable outcome, and therefore primary prosthetic replacement should be considered.

Adult↗
PubMed1997

[Functional electromyography analysis of radial replacement operation].

The aim of this electromyographic study was to evaluate the functional result of tendon transfers for radial palsy. Eighteen patients were compared to 16 healthy volunteers. The intramuscular emg of four muscles was recorded in parallel during extension-flexion movements of the wrist and fingers. The data were stored on FM tape and evaluated off-line. Contrary to expectations, transferred flexor muscles revealed only part of their overall emg activity during extension. Therefore, an "extensor quota" (EQ) was calculated for each muscle. It reflects its emg activity during extension as part of its entire emg activity. In non-transferred flexors EQ was low (11-27%). High EQ values (69-91%) were seen in genuine extensors of healthy persons. In only 6 of 18 patients did transferred flexors show an EQ equivalent to genuine extensors (> or = 69%). Best functional results were seen in transferred flexor carpi ulnaris (median EQ 68%). The EQ of transferred pronator teres was low (median 18%) and minor to flexor carpi ulnaris in each patient (P < 0.05). It is concluded that in cases of radial palsy, pronator teres is not suitable for replacing extensor muscles. Superficial flexors of the fingers, however, work in synergy with extensors of the wrist. According to the la reflex connections involved, these muscles should be a good choice for regaining extension of the wrist.

Brachial Plexus↗
PubMed1997

[Clinical experiences with a new Wiedemann method of radial replacement operation].

Many modifications of tendon transfers have been described in the treatment of radial nerve palsy. Controversy persists over the muscles of choice to get the best results in motion of wrist and fingers. Patients with radial nerve palsy and treated by the method of Merle d'Aubigne in neurophysiological tests showed that the pronator teres did not work very well for extending the wrist. Thinking about the neurophysiologic principles it seemed that the flexor digitorum superficialis of the middle and ring fingers would make a better substitute for the wrist extension. From 1994 to 1997 four patients with radial nerve palsy had a transfer of the flexor digitorum superficialis tendons from the middle and ring fingers to the tendons of extensor carpi radialis longus and brevis additional the flexor carpi ulnaris and palmaris longus transfers. The functional recovery of two patients has been tested. The functional range of wrist motion of this two patients has been better than in patients with pronator teres transfers. It can be concluded that the new modification of tendon transfers is a good way of treatment of radial nerve palsy and should be done further.

Adult↗
PubMed1997

Mechanism of the natriuretic action of gamma-melanocyte-stimulating hormone.

To explore the mechanism underlying the natriuretic effect of gamma-melanocyte-stimulating hormone (gamma-MSH), we infused the peptide intravenously at 200 pmol/min into anesthetized rats. gamma-MSH led to a progressive increase in urinary sodium excretion (UNaV), whereas continuous infusion of the vehicle did not affect UNaV. Plasma immunoreactive gamma-MSH was nine times greater at 120 min after the start of the infusion than in vehicle-infused rats. Plasma atrial natriuretic peptide (ANP) concentration also increased as a consequence of the gamma-MSH infusion, and a strong correlation existed between the concentrations of the two peptides (n = 17, r = 0.81, P < 0.001). Urinary excretion of guanosine 3',5'-cyclic monophosphate and adenosine 3',5'-cyclic monophosphate increased as a result of the infusion. Antiserum to rat ANP blunted the natriuresis only slightly, suggesting that the increase in plasma ANP concentration was not a critical element in gamma-MSH natriuresis. gamma-MSH had no effect on ANP release from isolated rat right atrial strips superfused in vitro. Infusion of gamma-MSH (500 fmol/min) directly into one renal artery led to an ipsilateral natriuresis without change in UNaV from the contralateral kidney. Prior denervation of the infused kidney prevented the natriuresis resulting from intrarenal infusion. Intrarenal infusion of ANP (800 fmol/min) also produced ipsilateral natriuresis, which, however, was not affected by renal denervation. These studies confirm that the natriuretic action of gamma-MSH occurs primarily by an interaction with the renal nerves. Intravenous infusion of the peptide sufficient to produce a supraphysiological plasma gamma-MSH concentration also results in an increase in plasma ANP concentration; however, this increase at best plays only a minor role in the natriuresis following intravenous gamma-MSH infusion.

Animals↗
PubMed1996

Dietary sodium intake modulates pituitary proopiomelanocortin mRNA abundance.

The pituitary prohormone proopiomelanocortin gives rise to melanocortins of alpha, beta, and gamma primary structure in addition to corticotropin. Melanocortins have a variety of actions in mammals, and each is natriuretic. In particular, gamma-melanocyte-stimulating hormone has been shown to mediate reflex natriuresis after acute unilateral nephrectomy. We examined whether this peptide could play a role in longer term adjustments in sodium balance by measuring plasma gamma-melanocyte-stimulating hormone and corticotropin concentrations, as well as pituitary proopiomelanocortin mRNA abundance, in Sprague-Dawley rats ingesting either a low (0.07% NaCl) or high (7.5% NaCl) sodium diet. One week after the high sodium diet, plasma gamma-melanocyte-stimulating hormone concentration was double the value seen in rats on the low sodium diet (158 +/- 5 [SE] versus 76 +/- 9 fmol/mL, P < .001), a change that was accompanied by a fivefold increase in plasma atrial natriuretic peptide concentration but no change in plasma corticotropin. Whole pituitary proopiomelanocortin mRNA abundance, measured with a probe to exon 3 of the rat proopiomelanocortin gene, was significantly increased after 1 week of the high sodium diet compared with the low sodium diet and increased further at 2 and 3 weeks. This increase occurred primarily in the neurointermediate lobe as demonstrated by in situ hybridization; the content of gamma-melanocyte-stimulating hormone immunoreactivity was also increased in this lobe, but not the anterior lobe, after 1 week of the high sodium diet. These results demonstrate that high dietary sodium intake increases neurointermediate lobe proopiomelanocortin mRNA abundance compared with a very low sodium diet and also suggest that proopiomelanocortin is preferentially processed into gamma-melanocyte-stimulating hormone rather than corticotropin. These observations consequently raise the possibility of a role for this peptide hormone system in the adjustments to a high salt diet.

Animals↗
PubMed1995

Modulation of ANP-dependent effects of endothelin by inhibitors of neutral endopeptidase and cGMP phosphodiesterase.

Endothelin 3 (ET3) infusion increases the concentration of atrial natriuretic peptide (ANP) in plasma, which in turn raises hematocrit (Hct) through a transcapillary shift of plasma fluid and proteins into the interstitium, thereby reducing plasma volume (PV). The level of ANP bioactivity in peripheral target tissues is a function of ANP secretory rate and the turnover rate of ANP and its intracellular effector mechanisms. Neutral endopeptidase (NEP) is a widely distributed enzyme that participates in ANP catabolism, whereas cGMP-phosphodiesterase (PDE) degrades the intracellular second messenger of ANP. Therefore, we examined the consequences of inhibition of NEP and PDE on the ANP-dependent activity described above using the NEP inhibitor SQ 28,603 and the cGMP-PDE inhibitor zaprinast (M&B 22,948). In anesthetized, bilaterally nephrectomized rats, infusion of SQ 28,603 alone reduced mean arterial pressure (MAP) by 2.5 +/- 0.5% and increased Hct by 4.6 +/- 0.3% (P < .01 for both), leading to a calculated decrease in PV of 7.5 +/- 0.6%. These changes were prevented by pretreatment with rabbit anti-rat ANP antiserum. Simultaneous infusion of ET3 (25 ng/kg/min) and SQ 28,603 caused MAP to increase by 12.8 +/- 2.2%, an effect identical with that observed after ET3 alone (12.7 +/- 2.3%), whereas the increase in Hct of 9.4 +/- 0.4% was greater (P < .05) than the 7.5 +/- 0.4% increase seen with ET3 alone. ET3 increased plasma ANP concentration (599 +/- 135 vs. 108 +/- 13 pg/ml in vehicle-infused rats; P < .0001); ET3 and SQ 28,603 infused simultaneously increased plasma ANP even further (810 +/- 166 pg/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1994

[The contribution of the general and trauma surgeon in neurotraumatology: experiences and results of 10 years].

In acute medical service, general and traumatic surgeons are faced with the problem of treating severe head and brain injuries. In the department of surgery of the University Hospital in Munich, we have been performing neurotraumatological treatment since 1982. Within 10 years we saw 138 patients with severe head and brain injury. We had 48 cases of epidural hematoma. 81 of acute subdural hematoma. 84 of intracerebral contusional bleeding, 5 of depression fractures and 3 of hygromas. All these patients underwent surgical treatment. Osteoplastic trepanation was performed in 49 patients and osteoclastic trepanation in 60. Further interventions were elevation of the 5 depression fractures and evacuation of the 3 hygromas. Comparison with other investigations in departments of neurological surgery in the United States suggest that our results reflect a similar outcome (according to Jennet and Bond's outcome scale: 1, cured; 2, slightly handicapped; 3 severely handicapped; 4, vegetative state; 5, expired). The Traumatic Coma Data Bank (1991) recorded outcome of severe head and brain injuries as follows: 1, 27%; 2, 16%; 3, 16%; 4, 5%; 5, 36%; and our own results were: 1, 24%; 2, 17%; 3, 15%; 4, 5%; 5, 39%. Organization procedures and treatment strategies are suggested.

Adolescent↗
PubMed1993

[Treatment strategies in infections of the shoulder joint].

Shoulder joint infections are severe pathological conditions. Since the success of therapy is decisively dependent on early treatment, if joint infection is suspected, the patient should be hospitalized immediately. Characteristic suspicious features are extremely severe shoulder pain, adoption of a pain-relieving posture, and severe malaise. The diagnosis and differential diagnosis are discussed. In addition to selective parenteral administration of antibiotics, treatment comprises various methods of draining the shoulder joint in combination with temporary immobilization.

Anti-Bacterial Agents↗
PubMed1993

Natriuretic properties of melanocyte-stimulating hormones.

Proopiomelanocortin (POMC) is a protein that contains the amino acid sequences of numerous peptide hormones, including the melanocyte-stimulating hormones (MSH). MSH peptides of alpha, beta, and gamma primary structure are present in plasma, and all exhibit natriuretic activity. Intravenous infusion of alpha or beta-MSH leads to a time- and dose-dependent natriuresis, whereas gamma-MSH is reported to be natriuretic at low doses but antinatriuretic at high doses. The natriuretic activity of MSH peptides occurs without change in arterial pressure or renal hemodynamics, suggesting a possible direct tubular inhibition of sodium reabsorption. Intravenously infused gamma-MSH is associated with an increase in the plasma concentration of atrial natriuretic peptide. In addition, gamma-MSH also has a direct intrarenal natriuretic action that is dependent on the renal nerves. In rats, gamma-MSH-related peptides are involved in the reflex control of sodium excretion in situations such as the natriuresis that occurs (a) from the remaining kidney after acute unilateral nephrectomy, (b) from the contralateral kidney shortly after unilateral ureteral pressure elevation, and (c) after unilateral carotid artery traction. POMC-derived peptides (including MSH) are modulated in response to salt loading, and alterations in POMC metabolism and plasma peptide concentrations have been observed in genetically hypertensive rats and during the development of adrenal regeneration hypertension. In addition, plasma gamma-MSH levels are elevated in patients with severe congestive heart failure, and in primary hyperaldosteronism. These observations suggest a possible involvement of MSH-related peptides in sodium homeostasis as well as in certain forms of hypertension.

Animals↗
PubMed1992

The intra-articular pressure of the shoulder: an experimental study on the role of the glenoid labrum in stabilizing the joint.

It was shown on human corpses that the glenohumeral joint may be compared to a piston surrounded by a valve. The glenoid labrum, then, should work like the valve block, sealing the joint from atmospheric pressure. In order to test this hypothesis, 18 human shoulder preparations were studied. The mean stabilizing force obtained by atmospheric pressure was 146 N. Additionally, 15 patients without any sign of instability and 17 patients with an anterior instability of the shoulder were tested under general anesthesia. In stable shoulder joints, traction at the arm caused negative intra-articular pressure that could be correlated to the amount of force exerted. In contrast, unstable shoulder joints with a tear of the glenoid labrum (Bankart lesion) did not exhibit this phenomenon. For unstable shoulder joints, the piston-and-valve model is no longer valid. This enlarges the current concept of shoulder joint stability in two ways: (a) the absence of negative intra-articular pressure disturbs joint mechanics and (b) altered pressure receptors might disturb motor coordination that dynamically protects the shoulder from dislocating forces.

Adult↗
PubMed1992

Inhibition of neutral endopeptidase amplifies the effects of endogenous atrial natriuretic peptide on blood pressure and fluid partition.

Neutral endopeptidase (EC 3.4.24.11) is a wide-spread enzyme that degrades atrial natriuretic peptide (ANP). We studied the effects of a potent neutral endopeptidase inhibitor, SQ 28,603, given intravenously (30 mg/kg over 45 min) to anesthetized, bilaterally nephrectomized Sprague-Dawley rats. Infusion of vehicle alone was accompanied by a modest increase, 3.2 +/- 2.2% (mean +/- SE), in mean arterial blood pressure (MAP) and a slight rise in hematocrit (Hct) of 0.9 +/- 0.7%. After administration of SQ 28,603, MAP fell 3.2 +/- 0.5%, and Hct rose 4.9 +/- 0.5%, both significantly different from the changes with vehicle alone; the lesser increase in plasma protein concentration (2.5 +/- 0.4%) suggested an increase in vascular permeability to both plasma protein and fluid similar to that caused by ANP. When SQ 28,603 was given to rats pretreated with rabbit antirat ANP antiserum, blood pressure rose by 3.8 +/- 0.5%, and Hct increased by 1.0 +/- 0.4%, values very similar to those observed with vehicle alone. Inhibition of neutral endopeptidase therefore amplifies the actions of endogenous ANP on blood pressure and fluid partition.

Alanine↗
PubMed1992

Acute unilateral nephrectomy elicits a specific increase in plasma of peptides derived from the N-terminal region of proopiomelanocortin.

Acute unilateral nephrectomy (AUN) causes natriuresis from the contralateral kidney through neurohumoral reflex pathways that involve an increase in the plasma of peptides derived from the N-terminal region of the adrenocorticotropic hormone (ACTH)/beta-endorphin precursor proopiomelanocortin (POMC). To determine the specificity of these humoral changes, the concentrations in plasma of ACTH and two peptides arising from the N-terminal fragment (NTF) of POMC, NTF32-49 and gamma-melanocyte-stimulating hormone (gamma-MSH), and of another natriuretic peptide, atrial natriuretic peptide (ANP), were measured by RIA with highly specific antisera to these epitopes. Group I experiments followed the course of sodium excretion (UNaV) for 120 min after AUN or sham nephrectomy. UNaV more than doubled within 60 min of AUN, and this natriuresis was maintained for the remainder of the experiment, whereas UNaV in sham rats did not change. There was no difference in plasma immunoreactive (ir) ACTH or ir-ANP concentrations between sham and AUN rats 120 min after the procedure, but plasma ir-NTF concentration was double in AUN rats compared with sham (P < 0.03). In Group II experiments, animals were killed 30, 60, 90, or 120 min after AUN and the urinary response related to peptide concentrations in plasma. UNaV rose rapidly after AUN, reaching a maximum value within 45 min that again was double the control value and remained stable for the duration of the experiment, up to 120 min after AUN. There was no significant change in ir-ACTH or ir-ANP at any point after AUN compared with values in sham AUN rats. However, plasma concentrations of both ir-NTF and ir-gamma-MSH were elevated 30 min after AUN and reached values at 120 min that were again double the values in sham rats (P < 0.05 for both).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1992

[Closed treatment of fractures of the humeral head. Indications, technique, limits].

Beginning with the specific mechanism of injury and characteristic physical and radiographic signs, the different forms of conservative treatment of fractures of the upper humerus are presented. As a result of biomechanical principles, the forces that generate the fracture cause dislocations of the fragments, and these dislocations follow basic rules. A fracture is considered dislocated if any of the fragments are displaced over 1 cm or if the angulation is more than 45 degrees. In dislocated fractures of the proximal humerus, reduction is indicated. The technique is presented in detail for the different types of fractures. Minimally displaced fractures or those that may be reduced by closed methods and do not redislocate are usually managed by conservative treatment. The affected shoulder is immobilized as a rule in a Gilchrist sling for 1-2 weeks. Functional exercises begin as soon as false motion of the fracture can be excluded by careful examination. In order to achieve optimal functional recovery, the exercises should be continued for longer than the bone union; that can be expected at 6-8 weeks. The special features and limitations of conservative treatment are discussed in relation to the different types of fractures.

Combined Modality Therapy↗
PubMed1991

Renal nerves and the natriuresis following unilateral renal exclusion in the rat.

Both acute unilateral nephrectomy (AUN) and acute ureteral pressure elevation (UPE) stimulate sodium excretion (UNaV) from the contralateral kidney, a response which in each case is interrupted by prior denervation of either kidney. Yet the natriuresis after AUN is known to be related to an increase in the plasma concentration of a gamma-melanocyte stimulating hormone (gamma-MSH)-like peptide. In anesthetized rats, sham AUN had no effect on contralateral UNaV, and plasma immunoreactive (IR) gamma-MSH concentration was 10.6 +/- 3.0 (SD) fmol/ml. In rats with intact renal innervation, UNaV more than doubled after AUN (P less than 0.001), and IR-gamma-MSH was increased to 14.9 +/- 4.6 fmol/ml (P less than 0.025). Unilateral renal denervation led to the expected increase in ipsilateral and decrease in contralateral UNaV, and neither sham AUN nor AUN of the denervated of innervated kidney influenced UNaV. In all three of these groups, IR-gamma-MSH concentration was reduced below the sham or post-AUN values seen in rats with innervated kidneys, to 4.9 +/- 3.3, 3.8 +/- 3.4, and 2.8 +/- 3.5 fmol/ml, respectively (P less than 0.001 for all). These results suggested that removal of renal afferent nerve input by renal denervation lowered basal IR-gamma-MSH activity and prevented the stimulated level normally seen after AUN. To examine the effect of stimulating afferent renal nerve activity, we carried out UPE, a maneuver known to increase ipsilateral afferent renal nerve traffic through activation of renal mechanoreceptors, as well as cause a natriuresis from the contralateral kidney.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗