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 mechanism of action of endogenous tachykinins [substance P (SP) and neurokinin A and B (NKA and NKB)] and of receptor-specific tachykinin analogues (SP methyl ester (SPME), [beta-Ala8]NKA-(4-10), and senktide) was examined in circular muscle of guinea pig stomach. Cross-desensitization studies confirmed that SPME and SP interacted with NK-1 receptors, [beta-Ala8]NKA-(4-10) and NKA with NK-2 receptors, and senktide and NKB with NK-3 receptors. NK-1 and NK-3-receptor agonists induced relaxation and stimulated vasoactive intestinal peptide (VIP) release and nitric oxide (NO) production: tetrodotoxin abolished VIP release, NO production, and relaxation, converting the response to NK-1-receptor agonists to contraction; the NO synthase inhibitor NG-nitro-L-arginine (L-NNA) abolished NO production, partly inhibited VIP release (56-64%, P < 0.01), and abolished relaxation; the VIP antagonist VIP-(10-28) partly inhibited NO production (73-74%, P < 0.001) and relaxation (56-58%, P < 0.01); and atropine augmented relaxation by 28-35% (P < 0.01). The pattern of inhibition implied that: 1) relaxation was mediated by VIP and NO; 2) VIP release was partly dependent on NO production, since it was strongly inhibited by L-NNA; and 3) NO was largely produced by the action of VIP on muscle cells, since it was strongly inhibited by VIP-(10-28). NK-2-receptor agonists elicited only contraction that was not affected by tetrodotoxin; these agonists also inhibited VIP release, NO production, and relaxation induced by NK-1- and NK-3-receptor agonists.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Functional difference between SP and NKA: relaxation of gastric muscle by SP is mediated by VIP and NO. 768 82

The nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), administered i.v. (50 mg kg-1) or by iontophoresis, was tested on the responses of spinal dorsal horn neurones in cats anaesthetized with alpha-chloralose and spinally transected at the L1 level. Extracellular, single-unit recordings were obtained from functionally identified dorsal horn cells. All units included in this study were wide dynamic range neurones. L-NAME significantly reduced the responses of (i) twelve neurones to noxious thermal stimulation of the receptive field, (ii) nine neurones to noxious pinch, (iii) nine neurones to iontophoretic application of N-methyl-D-aspartate (NMDA) and (iv) ten neurones to iontophoretic application of substance P. The inhibition usually lasted for 50-70 min following i.v. administration and for 5-8 min after iontophoretic application of L-NAME. The responses of four neurones to iontophoretic application of quisqualate were not affected by L-NAME. The results suggest the possible involvement of nitric oxide in the mediation of the spinal effects of NMDA and substance P, and in the transmission of thermal and mechanical nociceptive imputs.
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PMID:L-NAME blocks responses to NMDA, substance P and noxious cutaneous stimuli in cat dorsal horn. 768 58

1. Effects of the alpha 2-adrenoceptor agonists, UK14304 and clonidine, the 5-HT1 receptor agonist, sumatriptan and the kappa-opioid receptor agonist, GR103545, on sensory neurotransmission in histamine-contracted guinea-pig isolated pulmonary artery (GPPA) have been studied. 2. Electrical field stimulation (EFS) induced frequency-dependent relaxations of histamine-contracted GPPA, which were attenuated by tetrodotoxin and capsaicin pretreatment but not by the nitric oxide synthase inhibitor, N omega-nitro-L-arginine methyl ester (L-NAME). 3. Substance P (0.3 microM) induced relaxations which were subject to rapid tachyphylaxis. Neither the NK1 receptor antagonist, (+/-)-CP 96,345, nor desensitization to substance P had any effect of EFS-induced relaxations of histamine-contracted GPPA. 4. Calcitonin gene-related peptide (CGRP; 3 and 30 nM) induced concentration-dependent relaxations of histamine-contracted GPPA. The putative CGRP receptor antagonist, CGRP8-37 (1 microM), markedly attenuated EFS-induced relaxations as well as relaxations induced by a low concentration of CGRP. 5. Sumatriptan (0.1 and 1 microM) and the selective kappa-opioid receptor agonist, GR103545 (10 and 100 nM) had no effect on EFS-induced relaxations of histamine-contracted GPPA. In contrast, the alpha 2-adrenoceptor agonists UK14304 (1-100 nM) and clonidine (300 nM) attenuated responses to EFS, the attenuation of UK14304 (100 nM) being reversed by yohimbine (300 nM). 6. It is concluded that in GPPA, where a presynaptic inhibition of sensory neurotransmission by alpha 2-adrenoceptor activation could be shown, there was no evidence for such modulation by either sumatriptan-sensitive 5-HT1 receptors or kappa-opioid receptors.
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PMID:Sensory nerve-mediated relaxation of guinea-pig isolated pulmonary artery: prejunctional modulation by alpha 2-adrenoceptor agonists but not sumatriptan. 768 95

Purposes of this study were to determine whether: (1) nitric oxide is involved in endothelium-dependent relaxation in helical strips of dog cerebral arteries; (2) relaxing factor distinct from NO is also involved, and (3) susceptibility to NG-nitro-L-arginine (L-NA), an NO synthase inhibitor, of the response to mediators liberating NO from the endothelium and nerve differs. Changes in isometric tension were recorded. In the strips contracted with prostaglandin F2 alpha, substance P and arginine vasopressin produced a relaxation which was abolished or reversed to a contraction by endothelium denudation. The relaxations were not influenced by indomethacin but were suppressed dose-dependently by L-NA, as was the response to nicotine that stimulates the non-adrenergic, non-cholinergic vasodilator nerve and liberates NO. The inhibitions were reversed by L- but not D-arginine. NO (acidified NaNO2)-induced relaxations were not reduced by L-NA. The inhibitory effect was greater in the responses to vasopressin than substance P; however, there was no significant difference in the response to nicotine vs. the peptides. Substance P increased the level of cyclic guanosine monophosphate (GMP) in the artery strips with the intact endothelium, the effect being abolished by endothelium denudation, L-NA and oxyhemoglobin. Relaxations caused by adenosine triphosphate (ATP) and adenosine diphosphate (ADP) were dependent partially on the endothelium. Treatment with L-NA attenuated the ATP-induced relaxation in the strips with endothelium but did not alter the response of denuded strips.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cerebroarterial relaxations mediated by nitric oxide derived from endothelium and vasodilator nerve. 768 37

1. Neuromuscular transmission in the circular muscle of the canine proximal colon was examined, in the presence and absence of nitric oxide synthase inhibitors, by use of mechanical and intracellular microelectrode recording techniques. 2. Electrical field stimulation (EFS; 0.1-20 HZ) produced frequency-dependent contractions of circular muscle strips which reached a maximum at 15 Hz. These responses were enhanced by NG-monomethyl-L-arginine (L-NMMA; 300 microM) and reduced by atropine (1 microM). The effects of L-NMMA were reversed by L-arginine (3 mM). All responses to EFS were abolished by tetrodotoxin (1 microM). 3. In the presence of atropine, phentolamine and propranolol (all at 1 microM; 'non-adrenergic, non-cholingergic (NANC) conditions'), EFS evoked frequency-dependent inhibition of phasic contractions which reached a maximum at 5 Hz. At higher frequencies of EFS, inhibition diminished, and these responses were followed by post-stimulus excitation. 4. Under NANC conditions and in the presence of L-NG-nitroarginine methyl ester (L-NAME; 200 microM), EFS evoked contractions at frequencies of 5 Hz or greater. These contractions were reduced by co-incubation with L-arginine (2 mM) and abolished by tetrodotoxin (1 microM). 5. In the presence of atropine (1 microM), EFS (5-20 Hz) caused frequency-dependent inhibition of electrical slow waves. In the presence of L-NAME (100 microM) and atropine, the inhibitory response to EFS was abolished and an increase in slow wave duration was seen at stimulation frequencies greater than 5 Hz. The effects of EFS on slow wave duration were abolished by tetrodotoxin (1 microM). 6. Atropine-resistant contractions to EFS were enhanced by indomethacin (10 microM) and reduced or abolished by the non-selective NK1/NK2 tachykinin receptor antagonist D-Pro2, D-Trp7,9 SP, and by the selective NK2 receptor antagonist MEN 10,376 (10 microM).7. Exogenous tachykinins mimicked non-cholinergic excitatory electrical and mechanical responses. The rank order of potency for contraction was neurokinin A>neurokinin B>substance P, suggesting a predominance of the NK2 sub-type of tachykinin receptors on colonic smooth muscle cells. Low concentrations of neurokinin A also increased the amplitude and duration of electrical slow waves.8. These results suggest that: (i) in previous studies, non-cholinergic excitatory responses were masked by the simultaneous release of NO; (ii) non-cholinergic excitatory responses occur throughout the period of stimulation and are not manifest only as 'rebound' excitation; (iii) one or more tachykinins, possibly,acting via NK2 receptors, may mediate non-cholinergic excitatory responses.
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PMID:Inhibition of nitric oxide synthesis reveals non-cholinergic excitatory neurotransmission in the canine proximal colon. 768 1

The vasodilating effect of substance P (SP) at the microvascular level is endothelium-dependent. In the present study we evaluated whether SP activates nitric oxide (NO) production by venular endothelial cell. We evaluated NO activation by measuring cyclic GMP levels in cultured endothelial cells isolated from coronary postcapillary venules of bovine origin (CVEC). Our results indicate that 5 min exposure of CVEC to 10 nM SP doubled basal cyclic GMP levels. Cell treatment with the NO synthase inhibitor L-NMMA reduced the basal levels of cyclic GMP and abolished the effect of SP but did not modify the increase in cyclic GMP in response to exogenous NO. These data indicate that a) microvascular endothelium responds in an autocrine fashion to NO with increased cyclic GMP levels, b) SP activates cyclic GMP pathway through NO production.
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PMID:Substance P increases cyclic GMP levels on coronary postcapillary venular endothelial cells. 769 Apr 46

An impairment of energy metabolism may underlie slow excitotoxic neuronal death in neurodegenerative diseases. We therefore examined the effects of intrastriatal, subacute systemic, or chronic systemic administration of the mitochondrial toxin 3-nitropropionic acid (3-NP) in rats. Following intrastriatal injection 3-NP produced dose-dependent striatal lesions. Neurochemical and histologic evaluation showed that markers of both spiny projection neurons (GABA, substance P, calbindin) and aspiny interneurons (somatostatin, neuropeptide Y, NADPH-diaphorase) were equally affected. Subacute systemic administration of 3-NP produced age-dependent bilateral striatal lesions with a similar neurochemical profile. However, in contrast to the intrastriatal injections, striatal dopaminergic afferent projections were spared. Both freeze-clamp measurements and chemical shift magnetic resonance spectroscopy showed that 3-NP impairs energy metabolism in the striatum in vivo. Microdialysis showed no increase in extracellular glutamate concentrations after systemic administration of 3-NP. The lesions produced by intrastriatal injection or systemic administration of 3-NP were blocked by prior decortication. However, the NMDA antagonist MK-801 did not block the effects of intrastriatal 3-NP, consistent with a non-NMDA excitotoxic mechanism. In contrast to subacute systemic administration of 3-NP, chronic (1 month) administration produced lesions confined to the striatum in which there was relative sparing of NADPH-diaphorase interneurons, consistent with an NMDA excitotoxic process. Chronic administration showed growth-related proliferative changes in dendrites of spiny neurons similar to changes in Huntington's disease (HD). These results are consistent with in vitro studies showing that mild metabolic compromise can selectively activate NMDA receptors while more severe compromise activates both NMDA and non-NMDA receptors. Chronic administration of 3-NP over 1 month produces selective striatal lesions that replicate many of the characteristic histologic and neurochemical features of HD.
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PMID:Neurochemical and histologic characterization of striatal excitotoxic lesions produced by the mitochondrial toxin 3-nitropropionic acid. 769 9

Substance P immunoreactivity is localized in discrete subsets of neurons in the human cerebral cortex and basal ganglia. In the normal human cerebral cortex, a subset of aspiny local circuit neurons in deep cortical layers and the cortical subplate contain preprotachykinin mRNA and substance P immunoreactive. These neurons, which contain NADPH diaphorase (NO synthase) activity, are strikingly depleted in Alzheimer's disease--in contrast to other local circuit neurons--suggesting that they may be an early target of the degenerative process. In the human basal ganglia, substance P immunoreactivity and mRNA are localized in a subset of spiny striatal neurons that project to the internal segment of the globus pallidus. These neurons are enriched in D1 dopamine receptors and dynorphin, and are calbindin and DARP 32 immunoreactive. A separate subset of aspiny striatal local circuit neurons also contain substance P immunoreactivity. Fiber and terminal staining is prominent in the matrix compartment of the ventromedial striatum and persists dorsally as a rim outlining patches that contain lesser amounts of immunoreactivity. Intense fiber and terminal staining is found in the pars reticulata of the substantia nigra. In Huntington's disease, substance P is depleted in the striatum in parallel with the dorsoventral gradient of neuronal loss. Terminal staining is progressively depleted in the pallidum and substantia nigra in tandem with striatal atrophy. Substance P receptor immunoreactivity, defined with two polyclonal antisera raised against synthetic peptides derived from the substance P receptor sequence, intensely labels a subset of large neurons in the nucleus basalis and striatum identical to neurons labeled with choline acetyltransferase and nerve growth factor receptor antibodies (although striatal cholinergic neurons do not contain nerve growth factor receptor immunoreactivity in the human). These cholinergic neurons resist degeneration in Huntington's disease but are sensitive to degeneration in Alzheimer's disease. Less intensely labeled neurons include pyramidal neurons in the hippocampal CA2 field, nonpyramidal neurons in CA1-4, pyramidal and nonpyramidal neurons in deep neocortical layers and in the cortical subplate. Substance P receptor immunoreactivity is not well defined in the human globus pallidus or substantia nigra.
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PMID:Substance P and substance P receptor histochemistry in human neurodegenerative diseases. 769 86

With the immunofluorescence technique, nitric oxide synthase (NOS)-like immunoreactivity (LI) was found in a few medium-sized and small sensory neurons in lumbar (L) 4 and L5 dorsal root ganglia (DRG) of normal rat, and in most of these neurons, NOS-LI coexisted with calcitonin gene-related peptide and sometimes with substance P and galanin. NOS-immunoreactive nerve fibers, terminals and small neurons were also located in the dorsal horn of the segments 4 and 5 of the rat lumbar spinal cord with the highest density in inner lamina II. Many NOS-positive neurons and fibers were seen in the area around the central canal. A sparse network of NOS-immunoreactive nerve fibers was found in the ventral horn. After unilateral sciatic nerve cut in the rat, the number of NOS-positive neurons increased in the ipsilateral L4 and L5 DRGs, mainly in medium and small neurons, but also in some large neurons and very small neurons. NOS-LI could now also be seen in the ipsilateral dorsal roots, and in an increased number of fibers and terminals in both outer and inner lamina II of the ipsilateral dorsal horn. The number of NOS-immunoreactive neurons in lamina II of the ipsilateral dorsal horn was reduced. In the monkey L4 and L5 DRGs, many small neurons were NOS-immunoreactive, but only a few weakly stained nerve fibers and terminals were found in laminae I-IV of the dorsal horn at L4 and L5 lumbar levels. A few NOS-positive neurons were present in lamina X. The number of NOS-immunoreactive neurons was somewhat reduced in DRGs 14 days after peripheral axotomy, but no certain effect was seen in the dorsal horn. These results, together with earlier in situ hybridization studies, demonstrate that axotomy in rat induces a marked upregulation of NOS synthesis in primary sensory neurons, thus suggesting a role for NO in lesioned sensory neurons. In contrast, no such effect was recorded in monkey, perhaps indicating distinct species differences.
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PMID:Nitric oxide synthase-like immunoreactivity in lumbar dorsal root ganglia and spinal cord of rat and monkey and effect of peripheral axotomy. 769 74

1. The role of endogenous nitric oxide (NO) as a modulator of enteric neurotransmission was investigated in longitudinal muscle myenteric plexus (LMMP) preparations of guinea-pig isolated ileum. 2. In tissues previously incubated with [3H]-choline, exogenous NO inhibited electrically-evoked [3H]-choline overflow as well as responses to exogenous agonists, indicating that NO has the potential of neuromodulation both pre- and postjunctionally. 3. A series of NO synthase inhibitors enhanced contractile responses to nerve stimulation indicating inhibitory neuromodulation by endogenous NO. 4. The potency order of the NO synthase inhibitors and their consistent effects after dexamethasone, on responses to nerve stimulation, indicate action on a constitutive NO synthase. 5. Responses enhanced by NO synthase inhibitors were inhibited by the substance P receptor antagonist, spantide, suggesting a neuromodulatory influence on substance P-like neurotransmission by the endogenous NO. 6. NO synthase inhibition did not modify contractile responses to application of acetylcholine or substance P, or [3H]-choline overflow, indicating that endogenous NO mainly has a prejunctional inhibitory action on substance P-like neurotransmission. Nor did it modify responses to direct electrical muscle stimulation in the presence of tetrodotoxin. This suggests a prejunctional enhancing effect by NO synthesis inhibition. 7. Evidence for endogenous NO modulation of acetylcholine release was obtained when NO synthase inhibition modified atropine-sensitive, nerve-mediated contractile responses. However, [3H]-choline overflow was unaltered by NO synthase inhibition. 8. NO synthase inhibition did not modify responses to inhibitory neurotransmission. 9. The findings suggest that endogenous NO inhibits substance P-like motor neurotransmission, probably via prejunctional mechanisms. Cholinergic transmission may also be reduced by endogenous NO, acting prejunctionally.
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PMID:Modulation of cholinergic and substance P-like neurotransmission by nitric oxide in the guinea-pig ileum. 769 59


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