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)

Effects of ATP on substance P immunoreactivity were examined in cultured dorsal root ganglion neurons. We found that treatment of dorsal root ganglion neurons with ATP significantly depleted substance P immunoreactivity on the neurites and somata of the neurons. The effects of ATP were significantly inhibited by the purinergic P2 receptor antagonists suramin (30 microM) and pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid (10 microM). We also showed that ATP-induced depletion of substance P immunoreactivity from dorsal root ganglion neurons depended on the entry of Ca(2+). In a spinal cord slice preparation, we also found the internalization of neurokinin-1/substance P receptors in many dorsal horn neurons following the application of ATP or alpha,beta-methylene-ATP. Together these results indicate that activation of P2X receptors may result in release of substance P from primary afferent neurons.
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PMID:Depletion of substance P from rat primary sensory neurons by ATP, an implication of P2X receptor-mediated release of substance P. 1173 Nov 3

The P2X(7) purinergic receptor subtype has been cloned and emphasized as a prototypic P2Z receptor involved in neurotransmission in the central nervous system and ATP-mediated lysis of macrophages in the immune system. Less is known about the neurobiology of P2X(7) receptors in the enteric nervous system (ENS). We studied the distribution of the receptor with indirect immunofluorescence and used selective agonists and antagonists to analyze pharmacologic aspects of its electrophysiologic behavior as determined with intracellular "sharp" microelectrodes and patch-clamp recording methods in neurons identified morphologically by biocytin injection in the ENS. Application of ATP or 2'- (or-3'-) O-(4-benzoylbenzoyl) adenosine 5'-triphosphate (BzBzATP) activated an inward current in myenteric neurons. Brilliant blue G, a selective P2X(7) antagonist, suppressed the responses to both agonists. Potency of the antagonist was greatest (smaller IC(50)) for the current evoked by BzBzATP. The P2X(7) antagonists 1-[N,O-bis (1,5-isoquinolinesulfonyl)-N-methyl-l-tyrosyl]-4-piperazine (KN-62) and oxidized ATP also suppressed the BzBzATP-activated current. Micropressure application of BzBzATP evoked rapidly activating depolarizing responses in intracellular studies with "sharp" microelectrodes. Oxidized-ATP suppressed these responses in both myenteric and submucosal neurons. Rapidly activating depolarizing responses evoked by application of nicotinic, serotonergic 5-HT(3), or gamma-aminobutyric acid A (GABA(A)) receptor agonists were unaffected by brilliant blue G. Immunoreactivity for the P2X(7) receptor was widely distributed surrounding ganglion cell bodies and associated with nerve fibers in both myenteric and submucous plexuses. P2X(7) immunoreactivity was colocalized with synapsin and synaptophysin and surrounded ganglion cells that contained either calbindin, calretinin, neuropeptide Y, substance P, or nitric oxide synthase. The mucosa, submucosal blood vessels, and the circular muscle coat also showed P2X(7) receptor immunoreactivity.
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PMID:P2X(7) receptors in the enteric nervous system of guinea-pig small intestine. 1174 25

We investigated the receptor-mediated regulation of nifedipine-insensitive, high voltage-activated Ca(2+) currents in guinea-pig terminal mesenteric arterioles (I(mVDCC)) using the whole-cell clamp technique. Screening of various vasoactive substances revealed that ATP, histamine and substance P exert modulatory effects on I(mVDCC). The effects of ATP on I(mVDCC) after complete P2X receptor desensitization exhibited a complex concentration dependence. With 5 mM Ba(2+), ATP potentiated I(mVDCC) at low concentrations (approximately 1-100 microM), but inhibited it at higher concentrations (>100 microM). The potentiating effects of ATP were abolished by suramin (100 microM) and PPADS (10 microM) and by intracellular application of GDPbetaS (500 microM), whereas a substantial part of I(mVDCC) inhibition by milimolar concentrations of ATP remained unaffected; due probably to its divalent cation chelating actions. In divalent cation-free solution, I(mVDCC) was enlarged and underwent biphasic effects by ATPgammaS and ADP, while 2-methylthio ATP (2MeSATP) exerted only inhibition, and pyrimidines such as UTP and UDP were ineffective. ATP-induced I(mVDCC) potentiation was selectively inhibited by anti-Galpha(s) antibodies or protein kinase A (PKA) inhibitory peptides and mimicked by dibutyryl cAMP. In contrast, ATP-induced inhibition was selectively inhibited by Galpha(q/11) antibodies or protein kinase C (PKC) inhibitory peptides and mimicked by PDBu. Pretreatment with pertussis toxin was ineffective. The apparent efficacy for I(mVDCC) potentiation with PKC inhibitors was: ATPgammaS > ATP>/=ADP and for inhibition with PKA inhibitors was: 2MeSATP > ATPgammaS > ATP > ADP. Neither I(mVDCC) potentiation nor inhibition showed voltage dependence. These results suggest that I(mVDCC) is multi-phasically regulated by external ATP via P2Y(11)-resembling receptor/G(s)/PKA pathway, P2Y(1)-like receptor/G(q/11)/PKC pathway, and metal chelation.
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PMID:Multiple regulation by external ATP of nifedipine-insensitive, high voltage-activated Ca(2+) current in guinea-pig mesenteric terminal arteriole. 1189 51

The effect of trichloroethanol (TCEt), the active metabolite of chloral hydrate, on the intracellular concentration of calcium ([Ca(2+)](i)) was investigated in rat submandibular glands (RSMG) acini loaded with fura-2. TCEt (1 - 10 mM) increased the [Ca(2+)](i) independently of the presence of calcium in the extracellular medium. Dichloroethanol (DCEt) and monochloroethanol (MCEt) reproduced the stimulatory effect of TCEt but at much higher concentrations (about 6 fold higher for DCEt and 20 fold higher for MCEt). TCEt mobilized an intracellular pool of calcium, which was depleted by a pretreatment with thapsigargin, an inhibitor of the sarcoplasmic and endoplasmic reticulum calcium-dependent ATPases, but not with FCCP, an uncoupler of mitochondria. TCEt 10 mM inhibited by 50% the thapsigargin-sensitive microsomal Ca(2+)-ATPase. DCEt 10 mM and MCEt 10 mM inhibited the ATPase by 20 and 10%, respectively. TCEt inhibited the increase of the [Ca(2+)](i) and the production of inositol phosphates in response to carbachol, epinephrine and substance P. TCEt inhibited the uptake of calcium mediated by the store-operated calcium channel (SOCC). ATP and Bz-ATP increased the [Ca(2+)](i) in RSMG acini and this effect was blocked by extracellular magnesium, by Coomassie blue and by oxydized ATP (oATP). TCEt potentiated the increase of the [Ca(2+)](i) and of the uptake of extracellular calcium in response to ATP and Bz-ATP. TCEt had no effect on the uptake of barium and of ethidium bromide in response to purinergic agonists. These results suggest that TCEt, at sedative concentrations, exerts various effects on the calcium regulation: (1) it mobilizes a thapsigargin-sensitive intracellular pool of calcium in RSMG acini; (2) it inhibits the uptake of calcium via the SOCC; (3) it inhibits the activation by G protein-coupled receptors of a polyphosphoinositide-specific phospholipase C. It does not interfere with the activation of the ionotropic P2X receptors. The use of chloral hydrate should be avoided in studies exploring the in vivo responses to sialagogues.
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PMID:Multiple effects of trichloroethanol on calcium handling in rat submandibular acinar cells. 1205 35

Protein kinase D (PKD), also called protein kinase Cmu (PKCmu), is a serine/threonine kinase that has unique enzymic and structural properties distinct from members of the PKC family of proteins. In freshly isolated rat parotid acinar salivary cells, extracellular ATP rapidly increased the activity and phosphorylation of PKD. The stimulation by ATP required high concentrations, was mimicked by the P2X(7) receptor ligand BzATP [2'- and 3'-O-(4-benzoylbenzoyl)ATP], and was blocked by Mg(2+) and 4,4'-di-isothiocyano-2,2'-stilbene disulphonate (DIDS), suggesting that activation of PKD was mediated by P2X(7) receptors, which are ligand-gated non-selective cation channels. Phorbol ester (PMA) and the activation of muscarinic and substance P receptors also increased PKD activity. PKC inhibitors blocked ligand-dependent PKD activation and phosphorylation, determined by in vitro phosphorylation studies and by phospho-specific antibodies to two activation loop sites (Ser(744) and Ser(748)) and an autophosphorylation site (Ser(916)). ATP and BzATP also increased the tyrosine phosphorylation and activity of PKCdelta, and these stimuli also increased extracellular signal-regulated protein kinase (ERK) 1/2 activity in a PKC-dependent manner. PKD activation was not promoted by pervanadate (an inhibitor of tyrosine phosphatases) and was not blocked by PP1 (an inhibitor of Src family kinases) or genistein (a tyrosine kinase inhibitor), suggesting that tyrosine kinases and phosphatases did not play a major role in PKD activation. P2X(7) receptor-mediated signalling events were not dependent on Ca(2+) entry. These studies indicate that PKC is involved in cellular signalling initiated by P2X(7) receptors as well as by G-protein-coupled receptors, and demonstrate that PKD and ERK1/2 are activated in similar PKC-dependent signalling pathways initiated by these diverse receptor types.
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PMID:P2X7 receptors activate protein kinase D and p42/p44 mitogen-activated protein kinase (MAPK) downstream of protein kinase C. 1205 8

It was hypothesised that P2X(3) receptors, predominantly labelling spinal and cranial sensory ganglionic neurons, are also expressed in intrinsic sensory enteric neurons, although direct evidence is lacking. The aim of this study was to localise P2X(3) receptors in the enteric nervous system of the guinea-pig ileum, and to neurochemically identify the P2X(3)-expressing neurons. In the submucous plexus, cholinergic neurons expressing calretinin (CRT), were immunostained for P2X(3). These neurons made up about 12% of the submucous neurons. In the myenteric plexus, approximately 36% of the neurons expressed P2X(3). Half of the latter neurons were immunoreactive for CRT, whereas about 20% were immunoreactive for nitric oxide synthase (NOS). Based on earlier neurochemical analysis of enteric neurons in the guinea-pig, the myenteric neurons exhibiting P2X(3)/CRT immunoreactivity were identified as longitudinal muscle motor neurons, and those expressing P2X(3)/NOS immunoreactivity as short inhibitory circular muscle motor neurons. In both plexuses, no colocalisation was observed between P2X(3) and calbindin, a marker for intrinsic sensory neurons. Multiple staining with antisera raised against somatostatin, neuropeptide Y, substance P or neurofilament protein did not reveal any costaining. It can be concluded that in the guinea-pig ileum, intrinsic sensory neurons do not express P2X(3) receptors. However, this does not negate the possibility that extrinsic sensory nerves expressing P2X(3) are involved in a purinergic mechanosensory transduction pathway as demonstrated in other organs.
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PMID:Neurochemical identification of enteric neurons expressing P2X(3) receptors in the guinea-pig ileum. 1227 55

Whole cell patch recordings were obtained from medium diameter (35-45 microm) dorsal root ganglion neurons. Using electrophysiological parameters, we were able to subclassify acutely dissociated dorsal root ganglion cells into three uniform (types 5, 6 and 9) and one mixed class (type 8) of neurons. All subtypes (types 5, 6, 8 and 9) had broad action potentials (7.0+/-0.2, 5.2+/-0.4, 7.3+/-0.5 and 6.0+/-0.4 ms) and exceptionally long afterhyperpolarizations (112+/-9, 178+/-19, 124+/-31 and 204+/-33 ms). Long afterhyperpolarizations have been linked to mechanically insensitive (silent) nociceptors by other laboratories [Djouhri et al., J. Physiol. 513 (1998) 857-872]. Chemosensitivity varied among cell classes. Cell types 5, 8 and 9 were capsaicin sensitive (45+/-13, 87+/-30 and 28+/-13 pA/pF; 5 microM) groups, while the type 6 cell was capsaicin insensitive. All cell types expressed ASIC-like (acid sensing ion channel) amiloride sensitive, proton-activated currents with a threshold of pH 6.8 and a peak near pH 5.0. All medium sized cells were sensitive to ATP (50 microM) and exhibited the 'mixed' form of ATP-gated current [Burgard et al., J. Neurophysiol. 82 (1999) 1590-1598; Grubb and Evans, Eur. J. Neurosci. 11 (1999) 149-154]. Immunohistochemistry performed on individual cells indicated the expression of both P2X(1) and P2X(3) subunits. Electrophysiologically defined classes were histochemically uniform. All types were examined for the presence of substance P (SP), calcitonin gene related peptide (CGRP) and binding of isolectin B4 (IB4). All subtypes expressed CGRP immunoreactivity. Types 5 and 8 co-expressed SP and CGRP immunoreactivity and also bound IB4. Subtypes 6 and 9 were positive for neurofilament m. It is likely that these cells represent major classes of myelinated and unmyelinated peptide expressing nociceptors.
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PMID:Chemical responsiveness and histochemical phenotype of electrophysiologically classified cells of the adult rat dorsal root ganglion. 1240 18

Nocifensive behaviors induced by the intradermal injection of three different P2X receptor agonists, ATP, BzATP or alpha,beta-meATP, into a hindpaw were measured in rats that were injected intrathecally with either an NMDA (MK-801) or an NK-1 (L-703,606) receptor antagonist or were pretreated systemically with the VR1 agonist resiniferatoxin (RTX). The same procedures were performed in animals injected intradermally with either capsaicin or formalin. Spinal infusion of MK-801 (10-50 nmol/10 micro l) similarly reduced the number of nociceptive events triggered by each of the P2X agonists and was also effective against capsaicin and formalin induced behaviors. Intrathecal administration of L-703,606 (50-100 nmol/10 micro l) had its greatest antinociceptive effect against capsaicin-induced behaviors followed by ATP and BzATP. L-703,606 was completely ineffective against behaviors induced by formalin or the other P2X agonist, alpha,beta-meATP. Pretreatment with RTX 2 days prior to testing significantly decreased the number of nociceptive events caused by each of the P2X agonists as well as capsaicin and formalin (capsaicin>BzATP>ATP>formalin>alpha,beta-meATP). The remaining nociceptive events in RTX animals injected with alpha,beta-meATP were significantly higher than in animals injected with either ATP or BzATP. Intradermal administration of different P2X receptor agonists induced similar levels of nocifensive behaviors and activity at spinal NMDA receptors. Capsaicin-sensitive fibers were likely activated following injection of BzATP and ATP, but not alpha,beta-meATP, and appeared to trigger the spinal release of substance P. The differences in mechanisms employed by the different P2X agonists may be a function of respective selectivity for P2X receptor subtypes.
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PMID:Distinct neurochemical mechanisms are activated following administration of different P2X receptor agonists into the hindpaw of a rat. 1259 Nov 37

The characteristics of the different populations of sensory nerve terminals that selectively contact pulmonary neuroepithelial bodies (NEBs) in rat lungs were investigated after chemical denervation with capsaicin and compared with control lungs. Vagal calbindin D28k and P2X(3) purinoceptor immunoreactive (IR) afferent nerve terminals contacting NEBs appeared to have their origin in the nodose ganglion. Thick CB/P2X(3)-IR nerve fibers were seen to be myelinated and to lose their myelin sheaths just before branching and protruding intraepithelially between the NEB cells. This vagal sensory component of the innervation of NEBs was not affected by capsaicin nor expressed capsaicin receptors (vanilloid receptor subtype 1). A second sensory nerve fiber population that selectively innervates pulmonary NEBs in the rat lung consists of thin unmyelinated nonvagal substance P/calcitonin gene-related peptide IR nerve fibers, contacting mainly the basal pole of pulmonary NEBs, and having their origin in dorsal root ganglia. In concordance with vanilloid receptor 1 expression on these nerve terminals, the spinal sensory substance P/calcitionin gene-related peptide-IR component of the innervation of NEBs was depleted by systemic capsaicin treatment. The complex sensory innervation pattern of pulmonary NEBs characterized in the present study strongly suggests that, physiologically, pulmonary NEBs represent a group of intraepithelial receptors that may be able to accommodate various local and central reflex actions, in relation to both chemo- and mechanosensory stimuli.
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PMID:Dual sensory innervation of pulmonary neuroepithelial bodies. 1259 50

(1) The involvement of Rho-kinase (ROCK) in the contractile mechanisms mediating smooth muscle contraction of the rat urinary bladder was investigated using expression studies and the ROCK inhibitor Y-27632. (2) Both isoforms of ROCK (ROCK I and ROCK II) were detected in high levels in rat urinary bladder. (3) Y-27632 (10 micro M) significantly attenuated contractions of rat urinary bladder strips evoked by the G-protein coupled receptor agonists carbachol (58.1+/-10.5% at 0.3 micro M) and neurokinin A (68.6+/-12.7% at 1 micro M) without affecting contractions to potassium chloride (10-100 mM). In addition, basal tone was reduced by 47.8+/-2.0% by 10 micro M Y-27632 in the absence of stimulation. (4) Contractions of urinary bladder strips evoked by the P2X receptor agonist alpha,beta-methylene ATP (alpha,beta-mATP; 10 micro M) were also attenuated by Y-27632 (30.0+/-7.2% at 10 micro M). (5) Y-27632 (10 micro M) significantly attenuated contractions evoked by electrical field stimulation (2-16 Hz). The effect of Y-27632 on the tonic portion of the neurogenic response (4-16 Hz) was not significantly different from the effect of atropine (1 micro M) alone. (6) While the mechanism underlying the ability of Y-27632 to inhibit alpha,beta-mATP-evoked contractions remains undetermined, the results of the present study clearly demonstrate a role for ROCK in the regulation of rat urinary bladder smooth muscle contraction and tone.
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PMID:Expression and functional role of Rho-kinase in rat urinary bladder smooth muscle. 1264 76


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