Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Studies of renal afferent fibers and their functions have continued since the work of Pines in 1959 (Fiziol. Zh. SSSR Im. I M Sechenova 45: 1339-1347, 1959). The kidney contains mechanoreceptors and chemoreceptors that appear to have two major functions. First, renal mechano- and chemoreceptors evoke a variety of renorenal reflexes, while more global cardiovascular reflexes are primarily evoked by renal mechanoreceptors. A second function of renal afferent fibers is to cause the pain of renal disease. Recent studies suggest that renal afferent fibers may also regulate secretion of vasopressin from the pituitary gland. Substantial evidence indicates that, although most renal afferent fibers enter the spinal cord, their functions depend to a large extent on supraspinal circuitry. Thus our research has focused on defining characteristics of spinal neurons that relay renal information to the brain. In the cat, neurons in the L2-T11 segments with excitatory responses to renal A delta and C fiber input project to the medial medullary reticular formation and to the caudal and rostral ventrolateral medulla. Renal afferent information reaches these cells by way of the least splanchnic nerve and by way of more than one dorsal root. In the monkey spinothalamic neurons in the L3-T10 segments respond to renal nerve stimulation. Excitatory responses predominate, but inhibitory responses occur in L2 and L3. These cells also respond to renal A delta and C fibers. Stimulation of renal mechanoreceptors by occlusion of the ureteropelvic junction or renal vein excites feline spinoreticular neurons. Graded increases in renal vein pressure produce graded increases in cell responses. Activation of renal chemoreceptors increases activity of spinal interneurons. Within the L2-T11 segments, cells responding to ureteral occlusion are located caudally, cells with responses to renal artery occlusion are located rostrally, and cells responding to renal vein occlusion are located in between. The differential locations of cells with these inputs suggests the existence of a coding mechanism for different renal receptor populations. Distention of the renal pelvis is a potent stimulator of primate spinothalamic neurons. These neurons encode renal pelvic pressures in the noxious range and appear to be important in mechanisms of renal pain.
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PMID:Bowditch Lecture. Renal afferent inputs to ascending spinal pathways. 131 32

Pathophysiologic mechanisms of bradycardia during epidural anaesthesia (L3-L4 with 1% lidocaine, 38 ml) were evaluated by studying changes in selected cardiovascular and hormonal parameters. Six of eight subjects (analgesia to T8-T10) remained circulatory stable with no significant changes in heart rate (HR), mean arterial pressure (MAP) and thoracic impedance (TI). In one of two subjects MAP decreased after 25 min from 85 to 50 mmHg (11.3 to 6.7 kPa), HR from 80 to 45 beats.min-1 while thoracic impedance increased from 25.5 to 26.5 ohm. End-systolic diameter (ESD) and end-diastolic diameter (EDD) of the left ventricle determined with echocardiography were reduced from 3.8 to 3.2 cm (17%) and 5.6 to 5.0 cm (11%), respectively. In the other subject MAP decreased after 25 min from 75 to 50 mmHg (10.0 to 6.7 kPa) and HR from 82 to 60 beats.min-1 while thoracic impedance increased from 28.8 to 29.6 ohm. ESD was reduced from 3.8 to 3.3 cm (13%), and EDD from 5.6 to 5.0 cm (11%). Both subjects recovered after infusion of saline and being placed in the head-down position. There were no consistent changes in plasma catecholamines, whereas pancreatic polypeptide increased from 5 and 3 to 152 and 69 pmol.l-1, vasopressin from 3 and 2 to 152 and 46 pmol.l-1, and aldosterone from 282 and 229 to 383 and 485 pmol.l-1, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Reduced left ventricular diameters at onset of bradycardia during epidural anaesthesia. 146 23

The distribution of leucine-enkephalin, methionine-enkephalin, neurotensin, somatostatin, substance P, oxytocin, vasopressin, neurophysin II, and serotonin in nerve terminals and fibers of sympathetic autonomic areas of the thoracolumbar (T-L) spinal cord was studied immunohistochemically in cats. Densities of these immunoreactive terminals and fibers were estimated in the intermediolateral nucleus pars principalis (IMLp) and pars funicularis (IMLf), the nucleus intercalatus (IC), and the central autonomic area (CA). Results for leucine- and methionine-enkephalin-like immunoreactivity (ENK) were similar and immunoreactivity for vasopressin was not observed. The greatest numbers of terminals and fibers in the IMLp region contained ENK, neurotensin-(NT), and serotonin-like immunoreactivity (5HT); terminals and fibers containing substance P-(SP) and neurophysin II-like immunoreactivity (NP2) were intermediate in number, and those containing somatostatin-(SS) and oxytocin-like immunoreactivity (OXY) were generally sparse. In the IC and CA, terminals and fibers containing ENK and NT were dense, those containing SP were moderate, and those containing OXY, NP2, and 5HT were sparsely represented. In the IMLp, where the largest proportion of sympathetic preganglionic neurons (SPN) is found, the greatest concentration of terminals and fibers containing ENK was found in segments T1-T8; for NT these segments were T1-T5 and T11-L1, for SP-C8-T2 and T11-L1, for NP2-T4-T7 and L2 to L3, and for 5HT-T1-T5. Terminals and fibers containing SS and OXY were present in segments C8-T10 and segments C8, T2-T8, T13, and L2 to L3, respectively. These results indicate that while ENK, NT, SP, NP2, and 5HT fibers and terminals are widely distributed throughout the T-L cord, they may influence to a greater degree the SPN in segments where they are present in greater numbers. As SS and OXY were not found at all levels of the IMLp, their functions may be more organ specific.
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PMID:Segmental distribution of peptide- and 5HT-like immunoreactivity in nerve terminals and fibers of the thoracolumbar sympathetic nuclei of the cat. 241 41

Experiments have been conducted to evaluate the effect of neuropeptide Y (NPY) administered at three distinct levels of the nervous system: 1) the posterior hypothalamic nucleus, 2) the spinal cord, and 3) the vascular noradrenergic neuroeffector junction. It was observed that NPY produced varying cardiovascular effects at these three distinct sites of the nervous system. Microinjections into the posterior hypothalamic nucleus resulted in an increase in blood pressure, which was reduced by prior microinjection of a muscarinic or H1-histamine antagonist but not an H2-histamine antagonist. In addition to the involvement of histaminergic and cholinergic pathways, the pressor effect of NPY appears to result from an increase in sympathetic outflow. NPY was also seen to decrease the potassium-induced release of norepinephrine (NE) from slices obtained from the posterior hypothalamic nucleus. In contrast to what was observed in the hypothalamus, the intrathecal injection of NPY at a level of T4 or T10 in anesthetized or T10 in unanesthetized rats resulted in a depressor effect as well as a decrease in heart rate. Both an alpha 2- and beta-adrenoceptor antagonist reduced the NPY effect. The depressor effect of intrathecal NPY was attenuated in rats pretreated with reserpine as well as in Spontaneously Hypertensive rats (SHR). These data suggest that the effects of NPY are closely associated with sympathetic preganglionic neurons in the spinal cord. At the vascular noradrenergic neuroeffector junction, NPY decreased the nerve stimulation-induced release of NE while potentiating the contractile response. Moreover, NPY potentiated the increase in perfusion pressure of the perfused mesenteric arterial bed in response to angiotensin, vasopressin, or phenylephrine.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cardiovascular effects and modulation of noradrenergic neurotransmission following central and peripheral administration of neuropeptide Y. 285 Jun 31

The role of variation of venous return on baroreflex control of heart rate during lumbar epidural anesthesia was investigated in 12 unpremedicated patients. Group 1 patients (n = 6) received 8 ml of 0.5% plain bupivacaine in the epidural space (L3-4) (mean upper level of analgesia at T10). Group 2 patients (n = 6) received 8 ml of saline at the same level in the epidural space. Following the epidural injection, phenylephrine (PHE) and nitroglycerin (NTG) were employed to alter the stimulation of baroreceptor sites before and during application of lower body positive pressure (LBPP). Plasma bupivacaine, catecholamines, renin activity, and vasopressin were assayed. In contrast to saline, epidural bupivacaine induced a decrease in systolic arterial and right atrial pressures (-11 +/- 4 and -3.2 +/- 0.7 mmHg, respectively, mean +/- SEM) without change in heart rate, an increase in baroreflex slopes during PHE and NTG injections (+5.9 +/- 1.6 ms/mmHg and +2.8 +/- 0.9 ms/mmHg, respectively), and a decrease in plasma norepinephrine (-248 +/- 89 pg/ml). The application of LBPP restored hemodynamic and reflex variables to preepidural analgesia values, whereas plasma catecholamines decreased further. Plasma renin activity and vasopressin were not modified at any time in either groups. This study indicates that lumbar epidural anesthesia enhances cardiac vagal tone mainly through a decrease in venous return.
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PMID:Influence of venous return on baroreflex control of heart rate during lumbar epidural anesthesia in humans. 308 Sep 22

Mean arterial pressure, heart rate, plasma catecholamines, renin activity, and vasopressin changes induced by a 30-degree head-up tilt were studied before and during epidural anesthesia with bupivacaine in eight elderly patients (ages 58-82 yr). The tilt performed before epidural anesthesia did not modify mean arterial pressure, heart rate, plasma catecholamines, renin activity, and vasopressin at 5 and 15 min. During epidural anesthesia, the superior level of analgesia ranged from T4 to T10. Epidural anesthesia induced significant (P less than 0.05) decreases from control values in mean arterial pressure and plasma norepinephrine (from 85 +/- 6 to 67 +/- 8 mmHg and from 600 +/- 108 to 307 +/- 77 pg/ml, respectively, mean +/- SEM) without significant changes in heart rate, plasma epinephrine, renin activity, and vasopressin. However 5 and 15 min after tilt, significant decreases from pretilt values were measured in mean arterial pressure (from 67 +/- 8 to 57 +/- 6 and 55 +/- 6 mmHg, respectively) and in heart rate (from 70 +/- 8 to 63 +/- 7 and 62 +/- 7 beats/min). Simultaneously, an increase in plasma vasopressin (from 14.8 +/- 5.5 to 36.2 +/- 10.3 and 40.0 +/- 10.5 pg/ml) was recorded, whereas plasma norepinephrine and epinephrine remained unchanged. Posttilt plasma renin activity values at 5 and 15 min were increased significantly when compared with the preepidural values (2,752 +/- 1,168, 2,410 +/- 1,214 and 713 +/- 190 pg X ml-1 X h-1, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of epidural anesthesia on catecholamines, renin activity, and vasopressin changes induced by tilt in elderly men. 388 49

In conscious rats, intravenous treatment with the dopamine D2-like receptor agonist quinpirole, elicited a pressor effect, which is attributed to central dopamine D2 receptor-mediated activation of sympathetic outflow associated with arginine vasopressin release. This prominent central effect is opposed to peripheral sympathoinhibitory and spinal depressor effects. The present study investigated the effects of pre- and postnatal undernutrition on the central pressor responsiveness to quinpirole. Malnourished (MalN) rats were obtained by feeding dams a multideficient diet (providing 8% protein) during pregnancy and nursing. At 90 days of age, MalN rats weighed significantly less than control (CNT) rats born to dams fed standard commercially diet (23% protein) during pregnancy and nursing. Baseline mean arterial pressure and heart rate in MalN rats were comparable to those of CNT. Intravenous treatment with quinpirole (0.3 mg/kg) in MalN conscious rats induced a pressor effect, which was significantly reduced in both magnitude and duration, when compared with CNT rats. In both groups studied, pressor response to quinpirole was fully abolished by the peripheral and central dopamine D2 receptor antagonist, metoclopramide (5 mg/kg, i.v.) whereas was significantly enhanced after pretreatment with either intravenous (0.5 mg/kg) or intrathecal (40 microg per rat at T9-T10 level) domperidone, a dopamine D2 receptor antagonist that does not cross the blood-brain barrier. However, even under peripheral and spinal dopamine D2 receptor blockade, maximum pressor effect of quinpirole remained significantly reduced in MalN when compared with CNT rats. Neither the maximum pressor nor the bradycardiac responses to intravenous phenylephrine or arginine vasopressin differed between CNT and MalN rats. This study shows that undernutrition imposed during fetal life and suckling blunted the pressor response to quinpirole in conscious rats. This blunted response appears mainly related to desensitization of brain dopamine D2 receptors rather than enhanced peripheral and/or spinal dopamine D2 receptor-mediated depressor effect or vascular hyporesponsiveness to alpha1-adrenoceptor and vasopressin receptor stimulation.
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PMID:Pressor responsiveness to intravenous quinpirole is blunted in malnourished, conscious rats: central vs. peripheral and spinal mechanisms. 1517 53

This study investigated the importance of supraspinal vasopressin and glutamate neurones in regulating renal sympathetic activity as part of the response to an acute reduction in blood volume. Wistar rats anaesthetized with chloralose and urethane were instrumented to record arterial blood pressure, heart rate and left renal sympathetic nerve activity. Pharmacological agonists and antagonists to glutamate and vasopressin were applied to the renal outflow of the spinal cord via an intrathecal catheter inserted at the foramen magnum and with the tip at the level of T10. Both glutamate and vasopressin increased renal sympathetic activity, and these actions were shown to be selectively blocked by their respective antagonists. Removing 1 ml of venous blood from a femoral venous catheter elicited an increase of 26 +/- 2% in renal sympathetic activity. This response to mild haemorrhage was halved to 13 +/- 4% by prior intrathecal application of a selective V1a antagonist. Similarly, prior intrathecal application of kynurenic acid reduced the response to the mild haemorrhage from 28 +/- 2 to 12.6 +/- 2.8%. Intrathecal application of both antagonists together reduced the haemorrhage response even further to 8 +/- 3%. All the changes were statistically significant at P < 0.01. It is concluded that a small reduction in blood volume induces an increase in renal sympathetic activity dependent on vasopressin and glutamate release from terminals of supraspinal neurones. It is suggested that the vasopressin neurones most probably originate from the paraventricular nucleus of the hypothalamus.
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PMID:The role of supraspinal vasopressin and glutamate neurones in an increase in renal sympathetic activity in response to mild haemorrhage in the rat. 1669 94

This study was designed to examine the mechanism of heart rate (HR) responses elicited by the stimulation of hypothalamic paraventricular nucleus (PVN). Experiments were done in urethane-anesthetized, barodenervated, adult, male Wistar rats. Chemical stimulation of the PVN by unilateral microinjections of N-methyl-d-aspartic acid (NMDA) elicited increases in HR which were attenuated by bilateral vagotomy. PVN-induced tachycardia was also attenuated by the blockade of the spinal ionotropic glutamate receptors (iGLURs) which was accomplished by intrathecal injections at T9-T10 or direct application at T1-T4 of iGLUR antagonists. The blockade of spinal iGLURs combined with bilateral vagotomy completely blocked PVN-induced tachycardia. Blockade of GABA receptors in the medial nucleus tractus solitarius (mNTS) also attenuated the PVN-induced tachycardia. Complete blockade of PVN-induced tachycardia was also observed after the blockade of iGLURs in both the spinal cord and mNTS. Combination of the blockade of mNTS GABA receptors and spinal iGLURs also abolished PVN-induced tachycardia. PVN-induced tachycardia was not altered by the blockade of spinal vasopressin or oxytocin receptors at T1-T4. These results suggested that in barodenervated rats: 1) tachycardia elicited by the chemical stimulation of the PVN was mediated via both inhibition of vagal and activation of sympathetic outflows to the heart, 2) the vagal inhibition contributing to the PVN-induced tachycardia was mediated by the iGLURs and GABARs in the mNTS, 3) sympathetic activation contributing to the PVN-induced tachycardia was mediated via spinal iGLURs, and 4) spinal vasopressin and oxytocin receptors were not involved in the mediation of PVN-induced tachycardia.
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PMID:Mechanism of heart rate responses elicited by chemical stimulation of the hypothalamic paraventricular nucleus in the rat. 1902 29

This experiment was designed to assess the effects of prolonged whole body immersion (WBI) in thermoneutral and cold conditions on plasma volume and hydromineral homeostasis.10 navy "combat swimmers" performed three static 6-h immersions at 34 degrees C (T34), 18 degrees C (T18) and 10 degrees C (T10). Rectal temperature, plasma volume (PV) changes, plasma proteins, plasma and urine ions, plasma osmolality, renin, aldosterone and antidiuretic hormone (ADH) were measured. Results show that compared to pre-immersion levels, PV decreased throughout WBI sessions, the changes being markedly accentuated in cold conditions. At the end of WBI, maximal PV variations were -6.9% at T34, -14.3% at T18, and -16.3% at T10. Plasma osmolality did not change during and after T34 immersion, while hyperosmolality was present at the end of T18 immersion and began after only 1 h of T10 immersion. In the three temperature conditions, significant losses of water (1.6-1.7 l) and salt (6-8 g) occurred and were associated with similar increases in osmolar and free water clearances. Furthermore, T18 and T10 immersions increased the glomerular filtration rate. There was little or no change in plasma renin and ADH, while the plasma level of aldosterone decreased equally in the three temperature conditions. In conclusion, our data indicate that cold water hastened PV changes induced by immersion, and increased the glomerular filtration rate, causing larger accumulated water losses. The iso-osmotic hypovolemia may impede the resumption of baseline fluid balance. Results are very similar to those repeatedly described by various authors during head-out water immersion.
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PMID:Whole body immersion and hydromineral homeostasis: effect of water temperature. 1975 8


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