Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20366 (substance P)
 21,176 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present study was aimed at investigating which tachykinin receptor subtypes mediate the inhibitory effects of tachykinins a) on salt intake induced by sodium depletion, b) on water intake induced by subcutaneous hypertonic NaCl administration and c) on water intake induced by central angiotensin II injection. The study was carried out by evaluating the potency of action, following intracerebroventricular injection, of several peptides, including both naturally occurring tachykinins and synthetic peptides selective for a given receptor subtype. The results obtained show different rank orders of potency of the agonists in the different behavioral tests, thus suggesting that different receptor subtypes are involved in the effects of tachykinins on water and salt intake. NK-3 receptors appear to be involved in the inhibitory effect of tachykinins on depletion-induced salt appetite. NK-2 receptors apparently mediate the inhibitory effect of tachykinins on drinking induced by hyperosmotic NaCl administration, while NK-1 receptors are probably involved in the inhibition of angiotensin II-induced drinking.
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PMID:Tachykinin receptor subtypes involved in the central effects of tachykinins on water and salt intake. 184 83

The effects of chronic acrylamide treatment on the autonomic nervous system were investigated by histochemical and pharmacological studies. Histochemical studies showed that acrylamide caused different degrees of damage to different nerve fibre types: calcitonin gene-related peptide (CGRP)-immunoreactive (IR) nerves showed the greatest reduction in intensity and number; noradrenaline (NA)-containing nerves were somewhat less affected; substance P (SP)-IR nerves were reduced in number, but this was not significant. The profiles of SP- and particularly of CGRP-IR nerves from treated animals were noticeably different to those from the control group, being flattened and irregular. Periarterial nerve stimulation (4-32 Hz) of the isolated rat mesenteric arterial bed preparation at basal tone elicited frequency-dependent vasoconstrictor responses. The magnitude of these responses was significantly reduced at higher frequencies in acrylamide-treated animals. In preparations with tone raised by the addition of methoxamine (10(-5) M), and in the presence of guanethidine (5 x 10(-6) M), periarterial nerve stimulation elicited vasodilator responses. These responses, which result from stimulation of sensory nerves, were greatly reduced in acrylamide-treated animals. There was a tendency for mesenteric beds from acrylamide-treated animals to show increased vasoconstrictor responses to doses of exogenous NA, although this was not significant. Responses to exogenous adenosine 5'-triphosphate (a cotransmitter with NA from sympathetic nerves) were not affected. In the raised-tone preparation, vasodilator responses to exogenous CGRP (the principal vasodilator sensory transmitter of rat mesenteric arteries) were not affected by acrylamide treatment. Hence, it is unlikely that the reduced responses to nerve stimulation were due to defects in the postjunctional receptors for the principal transmitters of sympathetic and sensory-motor nerves. There was no difference in the ability of mesenteric beds from control and treated animals to vasodilate in response to acetylcholine or sodium nitroprusside, or to vasoconstrict in response to potassium chloride, indicating normal smooth muscle and endothelial responses. These results suggest that chronic acrylamide treatment produces peripheral autonomic neuropathy of rat mesenteric vessels, manifested as a dysfunction of sympathetic and sensory-motor nerves. Furthermore, the graded destruction of nerve types, such that damage occurred in the order: CGRP-IR greater than NA greater than SP-IR, indicated a differential sensitivity of different nerves to this toxin.
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PMID:Acrylamide-induced autonomic neuropathy of rat mesenteric vessels: histological and pharmacological studies. 194 19

Steroids (aldosterone and testosterone) and peptides of cerebral origin (angiotensin II and the tachykinins) control the salt intake of the rat. They arouse or suppress the behavior and they produce lifelong enhancements of NaCl intake. Need-induced salt intake (salt appetite or salt hunger), which is the consequence of sodium deficiency, is aroused by a synergy within the brain of cerebral angiotensin II and aldosterone. And prior episodes of sodium depletion produce enhancements of subsequent salt appetites, but only if the prior depletions were accompanied by angiotensin II and aldosterone action. Need-free salt intake, which occurs daily when the rat is in positive sodium balance is also enhanced by prior activations of angiotensin II and aldosterone. Both need-induced and need-free salt intake are suppressed by intracranial tachykinins. Nonmammalian tachykinins (eledoisin, physalaemin, kassinin) are both antidipsogenic and antinatriorexigenic, but amino-senktide, an analog of the mammalian tachykinin substance P with selective affinity for the NK 3 receptor, appears to be a selective antinatriorexigenic agent, and could provide a rational therapy for chronic over-consumption of salt.
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PMID:Neurohormonal control of salt intake in the rat. 195 25

Tracheas from control rats or rats sensitized to egg albumin (EA) were studied in vitro in Ussing chambers, and changes in short-circuit current (Isc) induced by the addition of antigen or agonists on the mucosal (luminal) side were recorded. Addition of EA (100 micrograms/ml) to tracheas from sensitized but not from control rats caused a slow increase of Isc beginning after 15 to 30 s and maximal at 3 to 4 min. This response was inhibited in the presence of doxantrazole, a mucosal mast-cell-stabilizing agent, but not by sodium cromoglycate. A separate group of rats was treated neonatally with capsaicin to deplete peptide neurotransmitters. Responses to EA were significantly lower in capsaicin-treated, sensitized rats than in untreated, sensitized control littermates. No difference was seen in the level of serum EA-specific IgE in these two groups. In tracheas from untreated rats, addition of substance P, capsaicin, platelet-activating factor, and acetylcholine caused an immediate and marked increase in Isc. Responses to substance P and acetylcholine were unaffected by capsaicin treatment. However, responses to capsaicin itself and also to PAF were reduced. These data indicate that changes of net ion transport across the airway epithelium are early phenomena of local hypersensitivity reactions, and that neurotransmitters such as substance P may play an important role in the control of these phenomena.
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PMID:Ion transport in rat tracheal epithelium in vitro. Role of capsaicin-sensitive nerves in allergic reactions. 196 24

To study the axon reflex as a contributing factor to capsaicin-induced bronchoconstriction in vivo, 30 guinea pigs weighing 325 +/- 7 g were randomly divided into four groups: Group 1, control (n = 6); Group 2, bupivacaine (n = 11); Group 3, tetrodotoxin (TTX, n = 10); and Group 4, tachykinin depletion (n = 3). Each animal was anesthetized with pentobarbital sodium, cannulated with a tracheal cannula and venous catheter, paralyzed with gallamine triethiodide, and artificially ventilated. All animals were treated with atropine and phenoxybenzamine, and a ganglionic blocking agent (chlorisondamine) was given to about half of the animals. Capsaicin (16 micrograms/kg) was intravenously injected to induce bronchoconstriction. Immediately upon the capsaicin being induced each animal exhibited a decrease in vital capacity, maximal expiratory flow and respiratory compliance, as well as a more than six-fold increase in residual volume, indicating severe bronchoconstriction. Then, the airway spasm decreased gradually toward the baseline values. The animals in Group 4 indicated a complete abolishment of the capsaicin-induced bronchoconstriction, whereas Group 2 and Group 3 displayed a significantly attenuated constriction at 15 to 20 min after capsaicin injection. Administration of chlorisondamine did not alter the capsaicin-induced bronchospasm. Since it is known that bupivacaine and TTX block nerve conduction, the data suggest that the axon reflex plays a significant role in the late phase of bronchoconstriction, which is apparently mediated via tachykinins.
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PMID:Role of the axon reflex in capsaicin-induced bronchoconstriction in guinea pigs. 202 6

1. Supernatants prepared from the rabbit brain, lung and liver caused an endothelium-dependent and volume-related contraction of the phenylephrine-pretreated rabbit aorta and inhibited relaxation due to acetylcholine (ACh). 2. Perfusion in situ of the rabbit lung or liver with Krebs solution substantially reduced or removed the endothelium-dependent inhibitor. Spectrophotometric analysis revealed the presence of substantial amounts of haemoglobin (1.8-2.1 microM) in these organ supernatants. 3. Supernatants prepared from the Krebs-perfused rabbit brain retained the ability to contract the phenylephrine-pretreated rabbit aorta and to inhibit relaxation due to ACh and substance P (SP). Rabbit brain supernatant did not reduce the vasodilator effect of sodium nitroprusside (NP) or nitric oxide (NO). 4. Rabbit brain supernatant contained low (less than 0.35 microM) concentrations of haemoglobin. 5. The inhibitory effect of rabbit brain supernatant was reversed by L-arginine (500 microM) but not D-arginine (500 microM). 6. The inhibitor of endothelium-dependent vasodilatation present in rabbit brain was not removed by dialysis (24 h, 4 degrees C) but was partially precipitated by ammonium sulphate (30% w/v). 7. Rabbit brain contains an endogenous inhibitor of vascular NO biosynthesis. The identity of this inhibitor is not known although it seems likely to be a large peptide or protein.
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PMID:Rabbit brain contains an endogenous inhibitor of endothelium-dependent relaxation. 208 9

We have previously shown that Entamoeba histolytica lysates contain the neurohormones serotonin, neurotensin, immunoreactive substance P, and probably acetylcholine, and that amebic lysates inhibit sodium and chloride absorption and stimulate chloride secretion in the rat descending colon as measured by the Ussing chamber-voltage clamp technique. We now demonstrate that these transport effects have both calcium-dependent and calcium-independent components. In addition, arachidonic acid metabolites of the cyclooxygenase pathway are probably involved in the Entamoeba histolytica-induced changes in colonic transport that are not dependent on Ca++ entry. Prostaglandin E2 (10(-5) M), indomethacin (10(-6) M), piroxicam (5 x 10(-5) M), and mepacrine (10(-4) M) partially inhibited the amebic lysate effect on active transport in the rat descending colon. In addition, verapamil (10(-4) M) partially inhibited the effect of amebic lysates. The effect of verapamil was additive with that of indomethacin, totally blocking the effect of amebic lysate on short-circuit current. However, amebic lysates do not contain prostaglandin E2 as measured by sensitive radioimmunoassay. Amebic lysates stimulated prostaglandin E2 release from rat colonic mucosal strips. Amebic lysate significantly increased colonic cyclic adenosine monophosphate content. Piroxicam inhibited the lysate-induced increase in colonic cyclic adenosine monophosphate content. These results indicate that although amebic lysate does not contain prostaglandin E2, it caused arachidonic acid metabolites to be produced by the cyclooxygenase pathway, and these are probably involved in the Entamoeba histolytica-induced changes in colonic transport. Neurohormones in Entamoeba histolytica may act directly on colonic tissue to stimulate intestinal secretion, probably via a Ca+(+)-dependent mechanism that is blockable by verapamil, or indirectly via stimulation of prostaglandin E2 generation and release from the rat colon via a cyclic adenosine monophosphate-dependent mechanism. These effects appear separate. The cyclic adenosine monophosphate-dependent secretion is the predominant mechanism in this model of colonic amebic diarrhea.
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PMID:Role of prostaglandins and calcium in the effects of Entamoeba histolytica on colonic electrolyte transport. 222 9

Neurokinin A, a member of the tachykinin family of neuropeptides, has been identified as a mitogen for cultured smooth muscle cells. Tachykinin-induced DNA synthesis has previously been shown to be mediated by a receptor-specific mechanism and to correlate with accumulation of phosphatidylinositol 4,5-bisphosphate breakdown products. In the present experiments, we have studied intracellular pH and expression of the proto-oncogenes c-myc, c-jun and c-fos in smooth muscle cells exposed to mitogenic concentrations of neurokinin A. Growth-arrested smooth muscle cells stimulated with neurokinin A responded with an amiloride-sensitive intracellular alkalinization, indicating Na+/H+ antiport activation. c-myc and c-jun mRNA expression was only slightly elevated by neurokinin A, while c-fos expression underwent a more pronounced increase. Maximal levels of c-fos transcripts were found after 15 min and 30 min following neurokinin A stimulation. The results demonstrate that neuropeptides may influence proto-oncogene expression in smooth muscle cells and suggest a mechanism by which peripheral neurons may modulate differentiation and growth of these cells.
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PMID:Neurokinin A induces expression of the c-fos, c-jun, and c-myc genes in rat smooth muscle cells. 217 99

The present study reports the effects of ICV administered eledoisin, the most potent anti/dipsogenic member of the tachykinin family, in three species. Sheep with chronic parotid fistula lost daily 200-400 mmol sodium in 3-4 l of saliva. During ICV infusion of eledoisin, 2 to 50 ng/min, a decrease in sodium intake was observed. If water was withheld for 22 hours, sheep normally drank 5.4 l water on presentation. During ICV infusion of eledoisin, 50 ng/min, water intake increased significantly. Wild rabbits lost 5 mmol sodium in 50 ml of urine after injection of furosemide. During ICV infusion of eledoisin, 30 ng/min, a decrease in sodium intake and an increase in water drinking was observed. Cows prepared with parotid fistula had access to sodium solution every other day to replace salivary sodium loss. During ICV infusion of eledoisin, 50 and 150 ng/min, a decrease in sodium intake occurred, and water intake was unaffected. These results confirm that central administration of eledoisin specifically influences ingestive behaviour in mammals and draws attention to some species differences in the observed effects.
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PMID:Sodium and water intake of sheep, rabbits and cattle during ICV infusion of eledoisin. 234 60

Sodium-replete pigeons drink excess 3% NaCl following concurrent treatment with both i.m. deoxycorticosterone acetate and pulse i.c.v. (p.i.c.v.) angiotensin II. This is not just a consequence of the water intake induced by p.i.c.v. angiotensin II, since the tachykinin eledoisin, given at equidipsogenic dose, does not evoke intake of salt. On the other hand, salt intake is not aroused in the sodium replete pigeon by continuous i.c.v. (c.i.c.v.) infusion of hyperosmotic mannitol (0.7 M) and c.i.c.v. infusions of hyperosmotic NaCl (0.3 M) or mannitol have no effect on the salt intake of the sodium deplete pigeon, or have effects that are unrelated to brain sodium. The salt appetite of the pigeon, like that of the rat, is evoked by an angiotensin and aldosterone synergy, and the angiotensin/aldosterone mechanism may be the general vertebrate theme of this behavior.
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PMID:Angiotensin/aldosterone synergy governs the salt appetite of the pigeon. 236 14


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