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)

1. Multiple distinct affinity states or sites of substance P (SP) receptors exist in freshly-prepared rat brain membranes. 2. Substance P receptors may couple with islet-activating protein (pertussis toxin) sensitive GTP-binding protein(s). 3. Substance P receptors may be regulated Mg2+ and Na+ in an opposite manner. 4. Some important factor(s), in addition to GTP-binding protein, appear to be involved in SP binding activity. 5. An apparent molecular weight of the SP binding site is approximately 46,000 Da.
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PMID:Substance P receptors in mammalian central nervous system. 170 76

Membranes isolated from a murine fibroblast B82 cell line (SKLKB82#3) transfected with the bovine stomach cDNA pSKR56S exhibited binding of [His(125I)1]neurokinin A (125I-NKA) to a single population of sites with a Bmax of 147 fmol/mg of protein and a Kd of 0.59 nM. Control cell lines had little or no specific binding. The ligand binding in SKLKB82#3 cells was reversible and was inhibited by peptides in the potency rank of neuropeptide gamma greater than neuropeptide K greater than neurokinin A greater than [10-norleucine]neurokinin A-(4-10) greater than substance P much greater than senktide (succinyl-Asp-Phe-MePhe-Gly-Leu-Met-NH2). Specific binding was enhanced by Mn2+, Mg2+, and Ca2+ and was inhibited by guanine nucleotide analogues. Thus, SKLKB82#3 cells have been transfected with NK2 receptors that have become associated with an endogenous guanine nucleotide-binding protein. In comparison with membranes from the hamster urinary bladder, a tissue enriched in NK2 receptors, NK2 receptor antagonists displayed markedly different potencies, either more or less potent, in inhibiting specific binding in membranes of the transfected cells. Furthermore, inhibition of 125I-NKA binding by nucleotide analogues was markedly different in SKLKB82#3 cells compared with hamster bladder tissue. The different binding profile in the cells is not due to an artefact introduced during cDNA transfection because a similar profile was also observed in bovine stomach membranes. These results may indicate the existence of two distinct NK2 receptors.
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PMID:Characterization of a tachykinin peptide NK2 receptor transfected into murine fibroblast B82 cells. 184 6

Intracellular recordings were made from identified choroid and ciliary neurons in the ciliary ganglion of the embryonic chick. Choroid neurons, which were innervated by multiple preganglionic fibers, frequently displayed noncholinergic slow excitatory postsynaptic potentials (EPSPs) following repetitive stimulation of the preganglionic nerve trunk. These slow potentials were blocked by high Mg2+/low Ca2+ buffer and were closely mimicked by bath application of substance P, which is known to be present within both populations of preganglionic nerve terminals. Substance P-induced depolarizations desensitized during prolonged exposure, at which time it was no longer possible to evoke slow synaptic potentials. Following manual voltage clamp to resting membrane potential, parallel increases in input resistance were seen during the slow EPSP and the response to substance P, suggesting that the two responses share common mechanisms. Ciliary neurons, which were innervated by a single preganglionic fiber and displayed dual electrical-chemical synapses, did not exhibit slow synaptic potentials and were unaffected by bath application of substance P. The magnitude and time course of fast nicotinic EPSPs elicited in ciliary neurons by 0.5 Hz presynaptic stimulation were also unchanged in the presence of 1 to 3 microM substance P. Although the ciliary and choroid neurons share a common embryological origin in the neural crest, they are specialized for quite different physiological roles. Integration of multiple presynaptic inputs occurs at choroid synapses, mediated by the presence of both subthreshold fast nicotinic EPSPs and the slow EPSP. In contrast, synapses on ciliary neurons have specializations which preclude any integrative function, including single innervation, a high quantal content, electrical coupling potentials, and a lack of slow synaptic potentials.
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PMID:Properties of choroid and ciliary neurons in the avian ciliary ganglion and evidence for substance P as a neurotransmitter. 241 83

An in vitro brainstem-spinal cord preparation of the newborn rat was used to examine the effects of neurotransmitters and transmitter candidates on respiratory frequency. Spontaneous periodic depolarization of the spinal ventral roots of the 4th or 5th cervical segment was observed at a frequency of 5-15 min-1 constantly for more than 5 h. The frequency of this depolarization was monitored as an index of the respiratory frequency. An elevation of the concentration of Ca2+ or Mg2+ caused a decrease in the respiratory frequency, whereas an elevation of K+ concentration caused an increase. The frequency was also increased by a reduction of pH. The highest frequency was observed at 27-28 degrees C. Dopamine, 5-hydroxytryptamine, histamine, acetylcholine, glutamic acid, substance P, and thyrotropin releasing hormone accelerated the respiratory frequency when applied by perfusion to the brainstem, whereas noradrenaline, gamma-aminobutyric acid, glycine, and [Met5] enkephalin and [Leu5] enkephalin slowed the frequency. Experiments with antagonists suggested that the stimulant effect of acetylcholine on respiratory frequency was mediated mainly by muscarinic receptors and the depressant effect of noradrenaline was mediated by alpha-adrenoceptors.
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PMID:A pharmacological study on respiratory rhythm in the isolated brainstem-spinal cord preparation of the newborn rat. 241 43

Using the sucrose gap method, the effect of taurine on the spinal cord of the bullfrog was investigated. Taurine inhibited the spontaneous potential and the ventral root reflex potential elicited by the stimulation of the dorsal root. The excitability of motoneuron did not necessarily diminish following taurine application. Taurine inhibited the responses induced by excitatory neurotransmitter candidates such as, glutamate and substance P, in a concentration dependent manner in the preparation, where the neurotransmission was abolished by Ca2+-deprivation and/or Mg2+-supplement. From these results, the depressant action of taurine on the electrical activities in the frog spinal cord may be interpreted, in part, by the inhibition of the response evoked by excitatory transmitter at postsynaptic site.
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PMID:Inhibitory action of taurine on motoneuron of frog spinal cord. 241 93

The effects of substance P (SP) on cholinergic transmission were studied at the neuromuscular junction of frogs by intracellular and voltage-clamp recording methods. Bath application of SP increased the amplitude of end-plate potential (e.p.p.) evoked in either low-Ca2+ -high Mg2+ or curare-containing solution. SP at a concentration of 0.1-1 microM produced a dose-dependent increase in the quantal content of the e.p.p., while having no significant effects on the quantal size. The frequency of m.e.p.p. was increased by SP. SP (1 microM) did not change the sensitivity of nicotinic receptors at the end-plate. These results suggest that SP presynaptically facilitates the neuromuscular transmission, increasing the evoked release of ACh from motor nerve terminals.
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PMID:The effects of substance P on neuromuscular transmission in the frog. 242 10

Intracellular methods were used to study the effects of serotonin and substance P (SP) on the electrical behavior of myenteric neurons in guinea-pig distal colon in vitro. Serotonin evoked either a short-duration transient depolarization, a long-lasting depolarization or a multiphasic response consisting of a rapid depolarization followed by a short duration hyperpolarizing potential and then a long-lasting depolarization. Application of SP evoked a long-lasting depolarization. Depolarizing potentials to both substances were accompanied by enhanced excitability that was reflected by repetitive spike discharge. Long-lasting depolarizations were associated with increased input resistance. The responses to serotonin or SP were unaltered by the presence of tetrodotoxin, hexamethonium or elevated extracellular Mg2+ and reduced Ca2+. Some neurons responded to both serotonin and SP indicating that both receptors coexisted on the same neuron. The putative SP antagonist, [D-Arg1,D-Phe5,D-Trp7,9,Leu11]SP did not affect the responses to SP. It did suppress the slow-depolarizing response to serotonin, while the fast response was unaffected. The responses to serotonin and SP in myenteric neurons of guinea-pig colon resembled the responses reported by others for small intestinal myenteric neurons.
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PMID:Actions of serotonin and substance P on myenteric neurons of guinea-pig distal colon. 245 28

1. The membrane actions of substance P (SP) and a related tachykinin, neurokinin A (NKA), have been investigated by means of a single-electrode, voltage-clamp technique in the immature rat dorsal horn neurons using an in vitro spinal cord slice preparation. 2. When the membrane potential was held at the resting level of between -75 and -55 mV, bath application of SP or NKA (10(-7) to 10(-5) M, for 1-3 min) induced an inward shift in the holding current lasting several minutes. The magnitude of this effect varied between 10 and 400 pA depending on the concentration of the peptides and the holding potential. 3. When a dorsal horn neuron was held at the resting level and subjected to 1-s depolarizing commands to membrane potentials between -60 and -35 mV, slow inward relaxations and inward tail currents, the latter on repolarization to the holding potential, were recorded. During the tachykinin-induced inward shift in the holding current, the inward relaxation and the tail current were augmented in a dose-related manner. 4. The SP-induced augmentation of the slow inward relaxation and the inward tail current is likely to be due to the enhancement of the activation of the Ca2+ current, because the effect was present, and even augmented in a zero-Ca2+, Ba2+-containing solution, it was reduced or completely abolished by zero-Ca2+, Co2+-, or Mg2+-containing solutions and is largely independent of the changes in external Na+, K+, or Cl- ions. Moreover, in the presence of the K+-channel blocker, tetraethylammonium (TEA), the effect is increased. 5. Depolarizing voltage commands to potentials positive to -35 mV evoked a large, outward K+ current response in the dorsal horn neurons, which was in part Ca2+-sensitive. The outward current response was augmented by SP. The SP effect persists, although being reduced in a zero-Ca2+, Ba2+- or Co2+-containing solutions. 6. In a zero-Ca2+ solution containing Co2+ and TEA, the augmentation of the Ca2+ current and the outward K+ current by SP was abolished. However, the SP-induced increase in a Ca2+-sensitive, voltage-insensitive conductance remained, although being reduced, and the response showed a reversal at about -28 mV. This current may be a result of a tachykinin-activated nonspecific increase in cationic permeability of the membrane of dorsal horn neurons, because the current is reduced by more than one-half when Na+ or Ca2+ is removed from the bathing medium.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Tachykinins modulate multiple ionic conductances in voltage-clamped rat spinal dorsal horn neurons. 247 Aug 66

Characteristics of in situ substance P release from the lumbar dorsal horn were investigated in decerebrated rabbits. Noxious mechanical stimuli produced by pinching the skin of a hind leg ipsilateral to the perfusion site remarkably and significantly increased the release of immunoreactive substance P, which was identified as substance P itself, using separation with high-performance liquid chromatography and radioimmunoassay. The noxious pinch did not affect the release of immunoreactive substance P, when applied to the contralateral hind leg. Both the basal and pinch-evoked release of immunoreactive substance P were largest in the dorsolateral part of the dorsal horn. The pinch-evoked release of immunoreactive substance P was abolished when the dorsal horn was perfused with a Ca2+-free medium containing 7 mM Mg2+ or with a medium with 10 microM tetrodotoxin added. The evoked release of immunoreactive substance P was also abolished following pretreatment of a stimulated region with the local anesthetic dibucaine, a procedure which inhibited the pinch-evoked aversive behavior in freely-moving rabbits. Among a variety of natural stimuli applied to the hind leg, noxious pinch and a subcutaneous injection of formaldehyde solution significantly evoked the release of immunoreactive substance P from the dorsal horn. The most intense heat or scalding stimulation increased the immunoreactive substance P release in two out of five experiments. However, other natural stimuli such as ice-cold, warm, noxious heat and innocuous mechanical stimuli produced no apparent changes in the release of immunoreactive substance P. These results suggest that among the noxious stimuli, only mechanical and inflammatory but not thermal stimuli lead to a release of substance P from the primary afferent terminals in the dorsal horn. The present findings suggest that, at least in rabbits, substance P-containing primary afferents have high-threshold mechanoreceptors. Substance P may participate in the transmission of information related to noxious mechanical and inflammatory stimulation from the periphery to the dorsal horn.
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PMID:Stimulus specificity of peripherally evoked substance P release from the rabbit dorsal horn in situ. 247 12

Mg2+ increased but Na+ and GTP decrease [3H]substance P (SP) binding to rat cerebral cortical membranes and to 10 mM 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulfonate (CHAPS)-solubilized membrane fraction. To determine the binding parameters that are modified by the cations and GTP, inhibition experiments of [3H]SP binding by unlabeled SP were performed in both of the preparations. Nonlinear least-squares regression analysis of data in the membrane fraction indicated that optimal fitting of the inhibition curves in the presence of 10 mM MgCl2 was attained with a two-site model, corresponding to a "high-affinity (H)" and a "low-affinity (L)" state. By omitting MgCl2, or by addition of NaCl and GTP, the [3H]SP specific binding was decreased, the H state disappeared, and the L state and a new "super-low affinity (SL)" state observed. The SP/[3H]SP inhibition curves in the cerebral cortical membranes by in vivo treatment with pertussis toxin (islet-activating protein) were similar to that in the presence of GTP in control membranes. The effects of MgCl2, NaCl, and GTP were greater in the CHAPS-solubilized fraction than in the membrane fraction. In contrast to the membrane fraction, the inhibition curves of [3H]SP binding by unlabeled SP in the presence of MgCl2 in the CHAPS-solubilized fraction were best fitted to a one-site model. The KD value was relatively close to that of the low-affinity state in the membrane fraction. Even with the addition of NaCl or GTP, or by reducing MgCl2 concentration to 1 mM, although the inhibition curves consistently fit the one-site model, the KD values changed only slightly.
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PMID:Comparison of the effects of ions and GTP on substance P binding to membrane-bound and solubilized specific sites. 247 98


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