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)

Peptides act as vasoconstrictors (for instance angiotensins, vasopressin) or vasodilators (the kinins, the neurokinins), both through direct activation of specific receptors in the vascular smooth muscles or indirectly through the release of other endogenous inhibitors of the vascular tone. Kinins and neurokinins as well as their multiple receptors have been analyzed in the present study to assess the possible contributions of peptides to vasodilatation. Kinin receptors, B1 and B2, have been characterized, using new selective agonists and antagonists. B1 and B2 receptors appear to present in endothelium (B2) and in smooth muscles (B2, B1) of a variety of isolated vessels of the dog and the rabbit, where they subserve both stimulatory and inhibitory effects. Vasodilator inhibitory mechanisms depend on the release of the endothelium-relaxing factor and/or of prostanoids from the endothelium or the smooth muscles, especially in the dog renal vessels, where both B1 and B2 receptors appear to be involved in causing vasodilatation. B2 receptors have also been shown to activate cardiovascular reflexes through a direct action on sensory fibers or on reflexogenic areas of the epicardium. Three types of receptors for neurokinins, namely NK-1, NK-2 and NK-3, have been identified by the use of naturally occurring peptides and of some analogues that act as selective agonists of a single receptor type. NK-1 receptors (particularly sensitive to substance P) have been shown to be present in endothelia where they promote the release of the endothelium relaxing factor, while NK-2 receptors (sensitive to neurokinin A) are found in the pulmonary artery of the rabbit and act directly to contract the smooth muscle.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Vasoactive peptides and their receptors. 217 37

Although three neurokinin receptors (NK-1, NK-2, NK-3) have been identified by radioligand binding assays, only the NK-1 and NK-3 types have been found in smooth muscle bioassays. In this study, evidence is presented demonstrating functional NK-2 type receptors in the guinea pig gallbladder (GPGB). The potencies of the following neurokinins were determined in the GPGB and the guinea pig ileum (GPI): substance P (SP), physalaemin (PH), eledoisin (EL), substance K (SK) and kassinin (KA). ED50 values were determined by linear regression analysis of the dose-related increases in the force generated by each peptide. In the GPI, the rank order of potency was SP = PH = EL greater than SK = KA, indicating NK-1 selectivity. In the GPGB, the relative potencies were SK greater than KA greater than EL much greater than PH greater than SP, which is similar to that reported for the NK-2 receptor in radioligand binding assays. These findings demonstrate the NK-2 receptor tissue selectivity of the GPGB.
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PMID:A novel bioassay for the NK-2 neurokinin receptor: the guinea pig gallbladder. 243 72

Luminal addition of tachykinins to the open-circuited canine tracheal epithelium produces a biphasic response in the transmucosal potential difference (PD). A rapid, transient decrease is followed by a subsequent rise, both phases being associated with changes in conductance. Concentration-response curves demonstrated the following orders of potency: substance P greater than physalaemin greater than eledoisin = kassinin for the tachykinins, and substance P greater than substance P-(4-11) greater than substance P-(6-11) using the C-terminal fragments. Both sequences are similar to those reported for the dog carotid artery. These observations were confirmed by cross-tachyphylaxis experiments. SP-O-methyl ester, a selective agonist for the SP-P (or NK-1) receptor, elicited identical responses, and exhibited cross-tachyphylaxis to substance P. Bradykinin produced similar luminal responses, though different receptors are involved, since no cross-tachyphylaxis was observed between bradykinin and the tachykinins.
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PMID:Luminal tachykinin receptors on canine tracheal epithelium: functional subtyping. 244 1

A photoreactive derivative, [(3'-125I) D-Tyro, (4'-N3)Phe8, Nle11]-substance P (SP) was prepared and iodinated using carrier-free [125I] to determine the apparent molecular weight of one sub-type of neurokinin (NK) receptor, the SP/NK-1 type. The unlabelled analogue competed for [3H]-SP sites with an IC50 of 10 nM. The radioactive photoprobe (KD approximately 0.17 nM, Bmax = 15.6 fmol/mg protein) was used to photoaffinity label membranes prepared from rat brain. Autoradiographs revealed that a single band with an apparent molecular weight of 46,000 daltons was specifically labelled. This labelling was inhibited by non-radioactive SP in a concentration-dependent manner (1.0 nM-0.1 mM) suggesting that the observed labelling represents the SP/NK-1 receptor type.
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PMID:Apparent molecular weight of substance P/neurokinin-1 receptors determined using a photoaffinity labelled probe, [(3'-125I) D-Tyro, (4'-N3)Phe8, Nle11]-substance P. 244 21

The autoradiographic localization of [125I]Bolton-Hunter substance P (BHSP) was examined in slide-mounted sections of dog kidney and dog renal artery and vein. Biochemical characterization of the binding in sections of dog kidney, demonstrated that BHSP binds to a population of non-interacting sites with high affinity (KD = 0.11 +/- 0.02 nM, Bmax = 0.29 +/- 0.05 fmol/section). The binding was displaced by tachykinins in the order SP greater than NKA much greater than NKB, indicative of binding to NK-1 receptors. BHSP binding to dog kidney was localized over glomeruli and endothelium of intrarenal arteries. There was binding associated with the endothelium and adventitia of the renal artery but not the vein. Binding of BHSP to arcuate arteries and to the renal artery was dependent on the presence of an intact endothelium. No evidence was obtained for receptors associated with any renal tubules. These results suggest that in the dog, vasodilation, diuresis and natriuresis in response to SP may result from an action primarily on the vascular elements of the kidney.
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PMID:Autoradiographic localization and characterization of substance P binding in dog kidney. 244 48

In the awake restrained rat the intrathecal (i.th.) administration of 6.5 pmol-40 nmol of substance P (SP), neurokinin A (NKA) or one of two selective NK-1 receptor agonists [Pro9, Met(O2)11]SP, denoted ana1 and [beta-Ala4, Sar9, Met(O2)11]SP , denoted ana2 decreased reaction time (RT) to a noxious radiant heat stimulus in a dose-related manner. The following rank order of potency was observed in relation to this response: ana1 = ana2 greater than SP much greater than NKA. The decrement of tail-flick latency was greatest at 1 min and RT returned to the basal level within 6-11 min post-administration. However, in some rats SP produced a small increase in RT (anti-nociception) at 6-11 min post-administration. The i.th. administration of neurokinin B (NKB) or a selective NK-3 receptor agonist [beta-Asp4, MePhe7]NKB), denoted ana3 induced an antinociceptive effect which was greatest at 1 min and lasted less than 11 min after NKB or more than 30 min after ana3 administration. The magnitude of the increase in RT produced by 65 pmol-40 nmol doses of these peptides is ana3 much greater than NKB much greater than SP. The effect of NKB (8.0 nmol) was significantly blocked (P less than 0.005) by prior i.th. administration of naloxone (opioid antagonist) but not by idazoxan (alpha 2-adrenoceptor antagonist), [Thi5,8, D-Phe7]BK (kinin antagonist), or following bilateral adrenalectomy. From these results, we conclude that NKB-induced antinociception is mediated by the spinal release of an opioid and not through a BK or NA mechanism. The results also suggest that the nociceptive and antinociceptive effects of neuro-kinins are mediated by the activation of NK-1 and NK-3 receptor subtypes respectively, in the rat spinal cord.
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PMID:Characterization of the effects produced by neurokinins and three agonists selective for neurokinin receptor subtypes in a spinal nociceptive reflex of the rat. 245 Nov 5

The three-dimensional structures of [Cys3,6,Tyr8]-, [Gly2,Cys3,6,Tyr8]- and [DCys3,Cys6]substance P, designed as conformational analogues of substance P, have been studied by 1H-NMR (500 MHz) in different solvents and by energy calculations. As previously observed for substance P and physalaemin, two tachykinins acting via the NK-1 receptor, [Cys3,6,Tyr8]substance P presents an alpha-helical structure of the 4----8 sequence in methanol. This structure is stabilized by a beta-turn III via the formation of three hydrogen bonds involving the Cys-6, Phe-7 and Tyr-8 NH groups. In contrast to substance P, two of these hydrogen bonds are still present in dimethyl sulfoxide and in water the Cys-6 NH hydrogen bond is the only one remaining, such that a beta-turn structure inside the ring can be envisaged. In close agreement with the NMR data, the energy calculations lead to three types of folding for the core of [Cys3,6,Tyr8]substance P: a beta-turn III, a less stable beta-turn I (delta E = 3 kcal), and a beta-turn II (delta E = 4.6 kcal). The structure of Gly-Leu-Met-NH2 is strongly affected by changing the hydrophobicity of the medium. The most stable calculated conformation is the helix; however, numerous unrelated structures are destabilized by about 2-3 kcal/mol. These data are analyzed and discussed in connection with the high potency of [Cys3,6,Tyr8]substance P for both the NK-1 and NK-3 binding sites; that is the internal region of tachykinins (non-homologous amino acids) might present a similar three-dimensional structure when bound to the receptors (which may be at the origin of some lack of selectivity), whereas paradoxically the selectivity may be due to the common C-terminal sequence.
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PMID:Analysis of tachykinin-binding site interactions using NMR and energy calculation data of potent cyclic analogues of substance P. 245 17

The ability of substance P, neurokinin A and its C-terminal fragment, neurokinin A-(4-10), to elicit NK-1 (salivation) and NK-2 (bronchospasm) receptor-mediated responses was investigated in anaesthetized guinea-pigs. Neurokinin A-(4-10) produced a dose-related increase in tracheal insufflation pressure and its maximal effect was similar to that elicited by neurokinin A and significantly greater than that of substance P. On the other hand substance P induced a potent dose-dependent increase of salivation while neurokinin A was significantly less potent. Neurokinin A-(4-10) did not exert any sialologic effect even at the dose of 100 nM/kg. These findings indicate that neurokinin A-(4-10) might be a valuable pharmacological tool for characterizing the involvement of NK-1 and NK-2 receptors in physiological responses in vivo.
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PMID:Neurokinin A-(4-10): a potent bronchospastic agent virtually devoid of sialologic properties in anaesthetized guinea-pigs. 245 32

The effects of neurokinins (NKs), tachykinins and some NK-related peptides (selective agonists for the NK-1, NK-2 or NK-3 receptors) have been investigated in the various sections of the rat lower urinary tract. In the isolated bladder, all peptides were substantially equipotent with the exception of senktide, an NK-3 agonist, which was distinctly less potent than the other compounds. Similar results were obtained in the isolated urethra. In these tissues, the maximal response to NK-1 agonists was distinctly less intense than that to the other peptides. In the bladder, exposure to phenoxybenzamine (30 microM for 90 min) reduced the response to NK-A but not that to substance P, KCl or field stimulation. In the isolated ureter, peptides active at both the NK-2 and the NK-3 sites [including senktide and [MePhe7]-NKB(4-10)] activated, at nanomolar concentrations a series of rhythmic contractions, whereas peptides active at the NK-1 site, were active only at micromolar concentrations. These findings provide further evidence that multiple NK receptors are present in the rat lower urinary tract. In the bladder, NK-2 and NK-1 sites mediate the direct response to NKs, in accordance with binding and autoradiographic data. In the ureter, both NK-2 and NK-3 sites may activate the direct contractile response to these substances.
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PMID:Neurokinin receptors in the rat lower urinary tract. 245 93

The autoradiographic distribution of the 3 neurokinin (NK) receptor sub-types, NK-1, NK-2 and NK-3, was compared in rat cerebral cortex during post-natal development using [125I]Bolton-Hunter-substance P, (2-[125I]iodohistidyl1)neurokinin A and [125I]Bolton-Hunter-eledoisin as respective radioligands. Throughout brain development, NK-1 receptor sites are present in low densities with some enrichment seen in lamina III while NK-3 binding sites are concentrated in layers IV and V. However, it appears that NK-2 receptors are mostly expressed in lamina VI and only during the first two postnatal weeks. These results demonstrate further the existence and differential ontogeny of 3 classes of NK receptors in rat brain cortex.
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PMID:Evidence for the existence of three classes of neurokinin receptors in brain. Differential ontogeny of neurokinin-1, neurokinin-2 and neurokinin-3 binding sites in rat cerebral cortex. 245 34


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