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 excitation of longitudinal antral muscle by substance P (SP) involves both a myogenic and a cholinergic effect. To examine if these responses are mediated by different neurokinin receptors, we studied the mechanical response and the release of [3H]acetylcholine from antral muscle strips in response to SP, substance P methylester (SPME), neurokinin A (NKA), neurokinin B (NKB), and several non-mammalian tachykinins. All peptides studied showed a dose-dependent inotropic and chronotropic effect on spontaneous phasic contractions. This ionotropic effect in longitudinal muscle was partially atropine sensitive for SPME, SP, and NKB but not for NKA, whereas neither atropine nor tetrodotoxin had an effect in circular muscle. In longitudinal muscle, all three neurokinins were equipotent. In longitudinal muscle treated with atropine and in circular muscle, the rank order of potency for the inotropic response was NKA greater than NKB greater than SP greater than SPME. For the chronotropic response the rank order was SPME, SP greater than NKA greater than NKB. NKA, NKB, and SP caused a dose-dependent, tetrodotoxin-sensitive increase in [3H]acetylcholine release from strips preincubated with [3H]choline. NKA was significantly more potent to release [3H]acetylcholine than either NKB or SP. The stimulated release was inhibited by [D-Ala2,D-Met5]methionine enkephalinamide and the SP antagonist, spantide. These results are consistent with the hypothesis that NKA is the natural ligand mediating the myogenic inotropic response in both muscle layers and the cholinergic response in longitudinal muscle.
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PMID:Characterization of the effects of neurokinins on canine antral muscle. 246 62

The cellular and subcellular distributions of the ionotropic alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-preferring glutamate receptor (GluR) in monkey striatum were demonstrated immunocytochemically using anti-peptide antibodies to individual subunits of the AMPA receptor. These antibodies specifically recognize GluR1, GluR4, and an epitope common to GluR2 and GluR3 (designated as GluR2/3). On immunoblots, the antibodies detect proteins ranging from 102 to 108 kDa in total homogenates of monkey striatum, hippocampus, and cerebellum. By immunoblotting, GluR1 and GluR2/3 are considerably more abundant than GluR4 in the caudate nucleus. Within the caudate nucleus, putamen, and nucleus accumbens, numerous neuronal perikarya, dendrites, and spines show GluR1 and GluR2/3 immunoreactivities. GluR1- and GluR2/3-enriched striatal neurons have the morphology, transmitter specificity, and distribution of medium-sized (10-20 microns) spiny neurons; large (20-60 microns) round neurons exhibit GluR4 immunoreactivity. GluR1 immunoreactivity, but not GluR2/3 or GluR4 immunoreactivity, is more intense in the ventral striatum (i.e., nucleus accumbens) than in the dorsal striatum, and GluR1 is enriched within dendritic spines in the neuropil of the nucleus accumbens and striosomes in the dorsal striatum. In the caudate nucleus, these patches of dense GluR1 immunoreactivity align with regions low in calcium binding protein immunoreactivity and high in substance P immunoreactivity. Within striosomes, GluR1 immunoreactivity is more abundant than GluR2/3 immunoreactivity; GluR4 immunoreactivity is sparse in striosomes, but the matrix contains large, GluR4-positive cholinergic neurons. This study demonstrates that, within monkey striatum, subunits of ionotropic AMPA GluR have differential distributions within striosomes and matrix. Furthermore, the results suggest that neurons within striatal striosomes and matrix may express different combinations of GluR subunits, thus forming receptors with different channel properties and having consequences that may be relevant physiologically and pathophysiologically. Neurons within these two striatal compartments may have different roles in the synaptic plasticity of motor systems.
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PMID:The striatal mosaic in primates: striosomes and matrix are differentially enriched in ionotropic glutamate receptor subunits. 767 61

Glutamate receptors are composed of subtype-specific subunits. Variation in the precise subunit composition of a receptor may result in significant functional differences. Thus, a precise knowledge of subunit composition on striatal neurons is a prerequisite for understanding the selective vulnerability of striatal neurons to excitatory amino acids. In the present study, we used an immunohistochemical double-labelling approach to localize ionotropic glutamate receptor subunits (NMDAR1, GluR1, GluR2/3, GluR4 and GluR5/6/7) on specific striatal neuron populations. Our results showed that striatal cholinergic and somatostatin interneurons were not labelled for the alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate, receptor subunits GluR1, GluR2/3 and GluR4. Most cholinergic and somatostatin interneurons (83.3% to 100%), however, were double-labelled for the N-methyl-D-aspartate receptor subunit NR1 and kainic acid receptor subunits GluR5/6/7. All parvalbumin interneurons were labelled for GluR1 and GluR4, and 96% GluR1 positive and 95% GluR4 positive neurons were also double-labelled as parvalbumin interneurons. About half of all parvalbumin interneurons co-localized with GluR2/3, and over 97% were labelled for NR1 and GluR5/6/7. Among striatal projection neurons, enkephalin-positive (mainly striatopallidal) neurons, striatonigral neurons (mainly substance P-positive) and calbindin-positive matrix neurons were not immunostained for GluR1 or GluR4. In contrast, 95% to 100% of each of these types of projection neurons were double-labelled for NR1, GluR2/3 and GluR5/6/7. Our results demonstrate that striatal neuron types differ in their expression of ionotropic glutamate receptor subunits and subtypes. The clear difference between striatal interneurons and projection neurons in ionotropic glutamate receptor subtypes/subunits supports the idea that differential glutamate receptor expression mechanism may account for the selective vulnerability of striatal projection neurons to excitotoxicity, and that glutamate receptor-mediated excitotoxicity may be involved in the striatal neurodegenerative diseases.
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PMID:Cellular expression of ionotropic glutamate receptor subunits on specific striatal neuron types and its implication for striatal vulnerability in glutamate receptor-mediated excitotoxicity. 880 93

Intracellular recording from lumbar motoneurons of the neonatal rat spinal cord in vitro was used to study how recently developed non-peptide antagonists such as SR-140333 and SR-48698, known to block distinct subtypes of tachykinin receptors peripherally, might affect synaptic transmission elicited by electrical stimulation of dorsal root fibres. SR-140333 (1 microM) preferentially antagonized responses mediated by an exogenously applied agonist acting on the NK1 receptor subclass, while SR-48968 (0.5 microM) preferentially reduced responses mediated by an exogenously applied agonist acting on the NK2 receptor subclass. SR-48968 did not affect fast or slow excitatory postsynaptic potentials (EPSPs) or 'wind-up' responses induced by repetitive, low-frequency stimulation (mimicking certain types of nociceptive input); binding studies using this radiolabelled ligand disclosed specific binding activity (21 fmol/mg protein) selectively displaced by an NK2 receptor agonist. SR-140333 reduced the late component of fast and slow EPSPs, and of wind-up. Pharmacological block of ionotropic glutamate receptors abolished all dorsal root-evoked EPSPs. In comparison to glutamate receptor blockers, SR-140333 was a weaker antagonist of slow synaptic responses, though it displayed preferential antagonism towards some components of the wind-up phenomenon. The present results provide evidence obtained with a novel NK1 antagonist that a neuropeptide (presumably substance P), although not directly released by primary afferents onto motoneurons, is a neurotransmitter (acting via NK1 receptors) in the pathway mediating slow synaptic responses of motoneurons, and is presumably involved in signalling nociceptive inputs from the periphery.
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PMID:An NK1 receptor-dependent component of the slow excitation recorded intracellularly from rat motoneurons following dorsal root stimulation. 884 46

Metabotropic glutamate receptors (mGluR) are coupled to multiple intracellular second messenger systems through G-proteins and densely expressed by medium spiny projection neurons in the rat striatum. Unlike ionotropic glutamate receptors which mediate rapid synaptic transmission, mGluRs are important for relatively long-lasting modulation of neuronal metabotropic activity, possibly including gene expression, in response to cellular stimulation. In this study, the effects of acute injection of the selective mGluR agonist (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (ACPD) on behavior and striatal neuropeptide mRNA expression were evaluated in chronically-cannulated rats. Unilateral injection of ACPD into the dorsal striatum at doses of 0.8, 4, 20, 100, 500 and 1000 nmol had no significant effect on spontaneous behavioral activity. However, intrastriatal ACPD (0.8, 4, 20 and 100 nmol) dose-dependently elevated preprodynorphin (PPD), substance P (SP) and preproenkephalin (PPE) mRNA expression in the dorsal striatum as revealed by quantitative in situ hybridization. PPD/SP mRNAs showed a biphasic response to a single injection of ACPD as the expression of these two mRNAs was increased at 3 and 6 h, decreased at 11 h, and returned to normal 24 h after ACPD administration. PPE induction in the dorsal striatum was significantly elevated as early as 2 h and remained even 24 h after ACPD was injected. In addition, the PPD and PPE mRNA induction by ACPD was blocked by intrastriatal pretreatment with the selective mGluR antagonist, (+)-alpha-methyl-4-carboxyphenyl-glycine. These data demonstrate a facilitatory regulation of constitutive expression of striatonigral PPD/SP, and striatopallidal PPE, mRNAs by local mGluR-mediated glutamatergic transmission.
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PMID:Metabotropic glutamate receptor agonist increases neuropeptide mRNA expression in rat striatum. 955 48

The modulatory action of substance P on synaptic transmission of CA1 neurons was studied using intra- or extracellular recording from the mouse hippocampal slice preparation. Bath-applied substance P (2-4 microM) or the selective NK1 receptor agonist substance P methylester (SPME, 10 nM-5 microM) depressed field potentials (recorded from stratum pyramidale) evoked by focal stimulation of Schaffer collaterals. This effect was apparently mediated via NK1 receptors since it was completely blocked by the selective NK1 antagonist SR 140333. The field potential depression by SPME was significantly reduced in the presence of bicuculline. Intracellular recording from CA1 pyramidal neurons showed that evoked excitatory postsynaptic potentials (EPSPs) and evoked inhibitory postsynaptic potentials (IPSPs) were similarly depressed by SPME, which at the same time increased the frequency of spontaneous GABAergic events and reduced that of spontaneous glutamatergic events. The effects of SPME on spontaneous and evoked IPSPs were prevented by the ionotropic glutamate receptor blocker kynurenic acid. In tetrodotoxin (TTX) solution, no change in either the frequency of spontaneous GABAergic and glutamatergic events or in the amplitude of responses of pyramidal neurons to 4 microM alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) or 10 microM N-methyl-D-aspartate (NMDA) was observed. On the same cells, SPME produced minimal changes in passive membrane properties unable to account for the main effects on synaptic transmission. The present data indicate that SPME exerted its action on CA1 pyramidal neurons via a complex network mechanism, which is hypothesized to involve facilitation of a subset of GABAergic neurons with widely distributed connections to excitatory and inhibitory cells in the CA1 area.
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PMID:Modulation by substance P of synaptic transmission in the mouse hippocampal slice. 978 2

Epithelial cells were isolated from rat trachea by incubation of the organ in a calcium-free medium. The intracellular concentration of calcium ([Ca(2+)](i)) was measured with the calcium-sensitive fluorescent dye fura2. In resting conditions, the cells maintained a low [Ca(2+)](i) in spite of the presence of millimolar concentration of calcium in the incubation medium. These cells had retained intracellular stores of calcium which were emptied after exposure of the cells to thapsigargin, an inhibitor of intracellular calcium ATPases. Substance P (125 nM) transiently increased 2.5-fold the [Ca(2+)](i). ATP (1 mM) doubled the [Ca(2+)](i) after a few seconds and further induced a sustained increase of the [Ca(2+)](i). Coomassie blue fully blocked the response to ATP and extracellular magnesium only inhibited the delayed response to ATP. Among purinergic analogs, only benzoyl-ATP (Bz-ATP), an agonist on P2X ionotropic purinergic receptors, reproduced the response to ATP. UTP and 2-methylthioATP (two agonists on P2Y metabotropic purinergic receptors) transiently increased the [Ca(2+)](i). Thapsigargin, ATP and Bz-ATP increased the uptake of extracellular calcium. RT-PCR analysis revealed that two metabotropic receptors (P2Y(1) and P2Y(2)) and two ionotropic receptors (P2X(4) and P2X(7)) were expressed by the cells present in the suspension. It is concluded that purinergic agonists can modulate the response of rat tracheal epithelial cells by several mechanisms. The activation of metabotropic receptors should mobilize intracellular IP(3)-sensitive calcium pools. The activation of the ionotropic receptors should not only open a non-specific cation channel leading to the entry of calcium but should also induce the formation of pores in cells expressing the P2X(7) receptors, which could be deleterious to these cells.
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PMID:Regulation by P2 agonists of the intracellular calcium concentration in epithelial cells freshly isolated from rat trachea. 1044 26

Substance P and glutamate are present in primary afferent C-fibers and play important roles in persistent inflammatory and neuropathic pain. In the present study, we have examined whether activation of different glutamate receptor subtypes modulates the release of substance P evoked by the C-fiber selective stimulant capsaicin (1 microM) from rat trigeminal nucleus slices. The selective NMDA glutamate receptor agonist L-CCG-IV (1-10 microM) enhanced capsaicin-evoked substance P release about 100%. This facilitatory effect was blocked by 0.3 microM MK-801, a selective NMDA receptor antagonist. The metabotropic glutamate receptor agonists L-AP4 (group III) and DHPG (group I) (30-100 microM) inhibited capsaicin-evoked substance P release by approximately 60%. These inhibitory effects were blocked by the selective metabotropic glutamate receptor antagonist (+/-)-MCPG (5 microM). On the other hand, AMPA and kainate (0.1-10 microM), did not significantly affect capsaicin-evoked substance P release. Thus, substance P release from non-myelinated primary afferents, and possibly nociception, may be under the functional antagonistic control of some metabotropic and ionotropic glutamate receptor subtypes.
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PMID:Opposite modulation of capsaicin-evoked substance P release by glutamate receptors. 1052 15

Effects of glutamate on synaptic transmission in the submucosal plexus of guinea-pig small intestine were studied with intracellular electrophysiological recording methods. Glutamate suppressed stimulus-evoked slow excitatory postsynaptic potentials (EPSPs) and increased the amplitude of slow inhibitory postsynaptic potentials (IPSPs) in submucosal neurons. The actions of glutamate were mimicked by the group I metabotropic glutamate receptor (mGluRs) agonist DHPG, but not by the group II agonist S-4C3HPG, the group III agonist L-AP4, or selective agonists for ionotropic glutamate receptors (iGluRs). Glutamate actions were suppressed by the selective group I mGluRs antagonist S-4CPG, but not by group II and III mGluRs antagonist CPPG or iGluRs antagonists. Glutamate suppressed substance P- and 5-HT-evoked slow EPSP-like responses and potentiated norepinephrine-induced slow IPSP-like responses. The results suggest that group I mGluRs mediate glutamate-induced suppression of slow EPSPs and potentiation of slow IPSPs in S-type uniaxonal submucosal neurons.
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PMID:Glutamate modulates neurotransmission in the submucosal plexus of guinea-pig small intestine. 1054 20

Nerve signals arising from sites of tissue or nerve injury lead to long-term changes in the central nervous system and contribute to hyperalgesia and the amplification and persistence of pain. These nociceptor activity-induced changes are referred to as central sensitization. Central sensitization involves an increase in the excitability of medullary and spinal dorsal horn neurons brought about by a cascade of events, including neuronal depolarization, removal of the voltage-dependent magnesium block of the N-methyl-D-aspartate (NMDA) receptor, calcium entry into neurons, phosphorylation of the NMDA receptor, a change in the cell's excitability, and an increase in synaptic strength. These changes also include activation of other ionotropic and metabotropic excitatory amino acid receptors, neuropeptides such as substance P, neurotrophins, and kinases involved in the phosphorylation process. Central sensitization occurs in trigeminal nociceptive pathways, and more robust neuronal hyperexcitability occurs following deep tissue stimulation than following cutaneous stimulation. By means of Fos protein immunocytochemistry, researchers have found that 2 distinct regions are activated: the subnucleus interpolaris/caudalis transition zone (Vi/Vc) and the caudal subnucleus caudalis. The latter exhibits changes very similar to those in the spinal dorsal horn, but the Vi/Vc zone likely is involved in autonomic nervous system processing and activation of the pituitary-adrenal axis. Descending systems are also an important component of the central sensitization process and provide the neural networks by which cognitive, attentional, and motivational aspects of the pain experience modulate pain transmission. These findings of nociceptor activity-induced neuronal plasticity have important clinical implications in the development of new approaches to the management of persistent pain.
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PMID:Central nervous system plasticity and persistent pain. 1082 30


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