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Query: UNIPROT:P20366 (
substance P
)
21,176
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The effects of intracerebroventricular administration of morphine, the selective mu-agonist
DAMGO
, the delta-agonist DPDPE, the kappa-preferring peptide dynorphin A(1-13) and the kappa-agonist U50,488H on locomotor behaviour in the guinea pig were investigated. Morphine (total dose = 0.01, 0.1, 1, 10, 200 nmol),
DAMGO
and DPDPE (total dose = 0.1, 1, 10, 100 nmol of each) produced piloerection and sedation, indicating that the responses of guinea pigs to mu- and delta-opioid agonists differed from those of rats and mice. In contrast, U50,488H (total dose = 10, 100 nmol) and dynorphin A(1-13) (total dose = 100 nmol) produced increased locomotor activity which was attenuated by pretreatment with naloxone and norbinaltorphimine, thus confirming the involvement of kappa-opioid receptors. Furthermore, pretreatment with spantide, baclofen, muscimol, bicuculline, MK-801, raclopride and atropine also inhibited the U50,488H-induced locomotor activity, suggesting the involvement of GABA, dopamine, excitatory amino acids,
substance P
and acetylcholine in this response.
...
PMID:Effects of intracerebroventricularly administered mu-, delta- and kappa-opioid agonists on locomotor activity of the guinea pig and the pharmacology of the locomotor response to U50,488H. 135 40
The effects of
substance P
(SP) on the binding of the selective mu opioid agonist [3H]
DAMGO
to brain membranes of CXBK and Swiss-Webster (SW) mice were compared. We have previously shown that subnanomolar concentrations of SP and N-terminal fragments of SP modulate
DAMGO
binding in SW brain membranes and hypothesized that modulation occurs via SP interaction with mu 1 sites. In the present study, binding assays using CXBK mice, a strain deficient in mu receptors including mu 1 sites, were performed to assess the effect of mu receptor deficiency on SP-induced modulation of
DAMGO
binding. Whereas the addition of 0.1 nM SP to the binding mixtures produced up to 30% increase in the values of Kd and maximum binding capacity (R) for the SW strain, SP produced little or no change in the case of CXBK strain. Maximum binding capacity for
DAMGO
was 43% less in the brain of CXBK mice than in SW mice. No difference was observed in the estimated binding parameters of the spinal cord for the two strains. Whereas pretreatment of brain membranes of SW mice using beta-funaltrexamine (beta-FNA) increased from 2- to 10-fold the modulatory effect of SP, CXBK brain membranes pretreated with beta-FNA remained nearly insensitive to modulation by SP. The effect of SP on the affinity of
DAMGO
binding in SW mice, but not in CXBK mice, was reversed by the addition of GTP. It is concluded that mu receptor deficiency can markedly influence SP-induced modulation of
DAMGO
binding.
...
PMID:Substance P modulation of DAMGO binding in the brain of CXBK and Swiss-Webster mice. 169 28
Aminoterminal fragments of
substance P
(SP) have been previously shown to produce effects distinct, and often opposite, from those produced by the C-terminal of SP. The present investigation was initiated to determine whether N-terminal fragments interact at binding sites distinct from the neurokinin-1 (NK-1) receptor where the C-terminal sequence of SP binds with high affinity, and distinct from mu-opiate receptors, where we have previously shown the N-terminal sequence of SP to interact. A tritium-labeled aminoterminal heptapeptide of SP, 3H-SP(1-7), was synthesized, purified, and used to characterize the binding of a variety of fragments of SP and opioids in the mouse brain and spinal cord membranes. Using the reduction of SP-induced caudally directed biting and scratching behaviors as an index of biological activity, 3H-SP(1-7) was shown to be equipotent to unlabeled SP(1-7). 3H-SP(1-7) was found to bind reversibly to a saturable population of sites. Scatchard analyses of concentration-dependent saturation of binding in the brain indicated a single population of noninteracting sites with a high affinity (Kd = 2.5 nM) and a low capacity (Bmax = 29.2 fmol/mg protein). Kinetic analyses indicated an apparent dissociation equilibrium constant of 2.1 nM. Two populations of binding sites were observed in the spinal cord, one with a very high affinity (Kd = 0.03 nM) and low capacity (Bmax = 0.87 fmol/mg protein), and the other with lower affinity (Kd = 5.4 nM) and intermediate capacity (Bmax = 19.6 fmol/mg protein). Specific agonists for NK-1, NK-2, and NK-3 and delta opioid receptors, carboxyterminal fragments of SP, and a variety of other peptides did not compete at the 3H-SP(1-7) binding sites, but structurally related N-terminal peptides and (D-Ala2, NMe-Phe4, Gly-ol)-enkephalin (
DAMGO
) were active in displacing the ligand. The binding site for 3H-SP(1-7) appeared to be a membrane-bound complex whose specific binding was dependent on the integrity of both proteins and phospholipids. These studies are the first to characterize the binding sites for the SP N-terminal partial sequence of SP that can be generated by metabolism in vivo. The expanding body of evidence for distinct biological activities of N-terminal metabolites of SP, together with the current characterization of N-terminal binding, strongly support the existence of an N-terminal-directed SP receptor. The characteristics of SP(1-7) binding sites are consistent with those expected for an SP N-terminal receptor.
...
PMID:Specific binding of substance P aminoterminal heptapeptide [SP(1-7)] to mouse brain and spinal cord membranes. 170 82
Superfusion of slices from the dorsal half of the lumbar enlargement of rat spinal cord with Krebs-Henseleit medium supplemented with 30 microM bacitracin allowed the collection of
substance P
-like immunoreactive material (SPLI), which was released at a rate of approximately 10 pg/4 min. Tissue depolarization by an excess of K+ (30-60 mM) or veratridine (50 microM) induced a marked increase in SPLI outflow, provided that Ca2+ was present in the superfusing fluid. K+- or veratridine-induced SPLI overflow could be modulated in opposite directions by mu and delta opioid receptor agonists. Thus, the two preferential mu agonists
Tyr-D-Ala-Gly-MePhe-Gly-ol
(DAGO; 10 microM) and Tyr-D-Ala-Gly-MePhe-Met(O)5-OH (FK-33824; 0.1 microM) enhanced SPLI overflow from depolarized tissues, whereas the selective delta agonists Tyr-D-Thr-Gly-Phe-Leu-Thr (deltakephalin; 3 microM) and [2-D-penicillamine, 5-D-penicillamine]enkephalin (50 microM) reduced it. The effect of DAGO was antagonized by a low concentration (1 microM) of naloxone but not by the selective delta antagonist ICI-154129 (50 microM). In contrast, the latter drug prevented the inhibitory influence of delta agonists on K+-induced SPLI release. Complementary experiments with morphine (10 microM) and [2-D-alanine, 5-D-leucine]enkephalinamide (3 microM), in combination with 1 microM naloxone or 50 microM ICI-154129 for the selective blockade of mu or delta receptors, respectively, confirmed that the stimulation of mu receptors increased, whereas the stimulation of delta receptors reduced, SPLI overflow. The results suggest that, at the spinal level, and antinociceptive action of delta but not mu agonists might involve a presynaptic inhibition of
substance P
-containing primary afferent fibers.
...
PMID:Opposite effects of delta and mu opioid receptor agonists on the in vitro release of substance P-like material from the rat spinal cord. 243 85
Substance P
(SP) appears to mediate many processes of the central nervous system, including pain. This report deals with modulation of opioid binding in the mouse brain by SP and SP fragments, as well as by salts and guanine nucleotides. Binding studies of the selective mu opioid receptor agonist [D-Ala2, MePhe4,Gly(ol)5]enkephalin (
DAMGO
) to mouse brain membrane preparations demonstrated that guanine nucleotide modulation of
DAMGO
binding affinity was modified by SP. However, SP had little or no influence on inhibition of
DAMGO
binding induced by salts, such as MgCl2, CaCl2, or NaCl. By replacing GTP with GppNHp, SP (0.1 nM) produced multiple affinity forms of the
DAMGO
receptor, while at a higher concentration (10 nM), SP lost its influence on
DAMGO
binding. Furthermore, 0.1 nM SP changed
DAMGO
binding parameters in a medium containing NaCl, CaCl2, and GppNHp such that the high- and low-affinity conformations of the receptor converted to a single site following the addition of SP to the incubation medium. While the C-terminal SP fragment SP(5-11) was without effect, the N-terminal SP fragments SP(1-9) and SP(1-7) appeared to imitate SP in modifying GppNHp-modulated
DAMGO
binding. These results suggest that SP functions as a modulator of opioid binding at the mu receptor and it appears that the N-terminus of SP plays a role in the modulatory process.
...
PMID:DAMGO binding to mouse brain membranes: influence of salts, guanine nucleotides, substance P, and substance P fragments. 768 1
Neutral endopeptidase 24.11 (NEP; "enkephalinase") may inactivate a number of centrally active neuropeptides including the enkephalins and
substance P
. In most areas of the central nervous system, the cell types which express NEP activity are not known. The hypoglossal nucleus (N.XII) was selected as a model system to characterize the cytochemical localization of NEP. The effect of hypoglossal nerve axotomy upon the distribution of NEP activity in the hypoglossal nucleus was compared to the effect upon cholinergic markers, the mu opiate receptor, and the enkephalins. By use of a fluorescence histochemical method, NEP was localized at all levels of N.XII to the soma and proximal processes of the majority of the apparent motor neurons in the nucleus. Fluorescent double-labeling studies revealed the presence of numerous enkephalinergic varicosities which localized to the neuropil surrounding NEP-stained motor neurons. To determine whether NEP was synthesized by these motor neurons, 18 rats received a unilateral transection of the hypoglossal nerve. A pronounced decrease in NEP staining in N.XII was observed on the operated side as early as 3 days following axotomy. This decrease persisted at all levels of the nucleus for about 5 weeks. By 7 weeks, the staining between the control and operated sides was indistinguishable. By contrast, there was no apparent change in the density or distribution of enkephalin-immunoreactive varicosities in five animals examined 6 to 32 days following axotomy. Radioligand binding of [3H]
DAMGO
to the mu-opiate receptor in N.XII was studied in 20 animals by quantitative autoradiography at 2, 6, and 11 days after axotomy. No significant changes in the level of radioligand binding to the mu-receptor were detected in response to axotomy. In contrast to the opiate system, the cholinergic enzymes choline acetyltransferase, acetylcholinesterase, and pseudocholinesterase showed a coordinate decrease in motor neuron-associated staining on the operated side of N.XII at 3, 6, and 11 days following axotomy which paralleled the decrease in NEP staining. By contrast, the lysosomal enzyme marker, acid phosphatase, showed a pronounced increase in staining on the operated side. The results of this study are consistent with the synthesis of NEP by cholinergic N.XII motor neurons and indicates that the enkephalins and NEP in N.XII are closely associated, but derive from separate neuronal populations. The widespread overlap in the distribution of NEP-stained motor neurons and enkephalinergic varicosities in N.XII provides additional anatomical support for a potential role for NEP in the inactivation of centrally active enkephalins.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:Differential response of neutral endopeptidase 24.11 ("enkephalinase"), and cholinergic and opioidergic markers to hypoglossal axotomy. 820 Oct 16
Substance P
(SP) increases, and the mu-specific opioid agonist
DAMGO
decreases neuronal firing within ventral pallidum (VP) of the basal forebrain. This study investigated a possibility that some VP neurons are oppositionally co-regulated by SP and
DAMGO
using microiontophoresis combined with the extracellular electrophysiological recordings from chloral hydrate-anesthetized rats. SP altered
DAMGO
's ejection current-response curve, decreasing Emax and slope, and increasing the Ecu50 (ejection current level at which 50% of the maximal response was obtained). The modulation was observed even at low ejection current levels that, when applied alone, were not sufficient to alter neuronal activity (i.e., subthreshold). Also,
DAMGO
altered the Emax and slope of SP's ejection current-response curve.
DAMGO
induced these effects even at subthreshold ejection current levels. The responses to each peptide were blocked by a receptor-specific antagonist. These findings demonstrate that SP and mu-activating opioids antagonize each other's effects on VP neuronal firing. Thus, they may interact as physiological antagonists in the regulation of VP-associated functions.
...
PMID:Interactions between the mu opioid agonist DAMGO and substance P in regulation of the ventral pallidum. 880 42
The amygdala (AMG), nucleus accumbens (NA) and ventral pallidum (VP) influence goal-oriented behaviors. However, the nature of the interactions among these regions has not been well characterized. Anatomical studies indicate that excitatory amino acids are contained in VP inputs from the AMG, and the NA is a primary source of VP
substance P
(SP) and opioids. The present study was designed to functionally characterize the NA and AMG projections to the VP, and to assess if opioids and SP can modulate AMG-mediated excitatory neurotransmission within the VP. To do so, extracellularly recorded electrophysiological responses of single VP neurons to electrical activation of VP afferents were monitored during microiontophoretic application of treatment ligands in chloral hydrate-anesthetized rats. The anatomically described glutamatergic inputs from the AMG, and SP inputs from the NA, were pharmacologically verified. It also was determined that even though iontophoretically applied SP increased the spontaneous activity of VP neurons, at ejection current levels that were below those necessary to produce this effect (termed sub-threshold), the
tachykinin
attenuated AMG stimulation-evoked glutamatergic neurotransmission. SP failed to modulate the excitations induced by iontophoretically applied glutamate suggesting that SP modulation of AMG-evoked excitations were mediated via a decrease in the pre-synaptic release of glutamate. Like SP, the effects of sub-threshold ejection currents of micro opioid agonist
DAMGO
on AMG-evoked responses were not predicted by the opioid's effects on spontaneous VP neuronal activity;
DAMGO
inhibited spontaneous firing but potentiated AMG-evoked glutamatergic neurotransmission. The opioid also potentiated effects of exogenous glutamate implying an interaction at a post-synaptic site. These results indicate that
tachykinin
and opioid neuropeptides contained in NA projection neurons can differentially modulate AMG glutamatergic inputs to the VP.
...
PMID:Substance P attenuates and DAMGO potentiates amygdala glutamatergic neurotransmission within the ventral pallidum. 959 91
Stimulation of the saphenous nerve in the anaesthetised rat results in cutaneous neurogenic oedema formation. We have examined the effect of a
tachykinin
NK1 and a bradykinin B2 antagonist, and a mu-opioid agonist on plasma extravasation observed in response to two differing nerve stimulating parameters (10 V, 1 ms, 2 Hz and 25 V, 2 ms, 10 Hz). The NK1 antagonist SR140333 abolished oedema, supporting the theory that an NK1 agonist is a primary mediator of neurogenic oedema. The B2 antagonist HOE 140 had no effect, indicating a lack of involvement of B2 receptors in this response. The pre-junctionally acting mu-opioid agonist
DAMGO
significantly inhibited oedema formation at the 10 V, 1 ms, 2 Hz (P < 0.001), but not the 25 V, 2 ms, 10 Hz stimulation parameters. Thus a post-junctionally acting NK1 antagonist inhibited neurogenic oedema formation induced by both stimulation parameters, whilst a pre-junctionally acting mu-opioid agonist acted only at 10 V, 1 ms, 2 Hz parameters. These findings could be of interest with respect to therapeutic approaches of pathophysiological conditions which involve a neurogenic component.
...
PMID:Activity of tachykinin NK1 and bradykinin B2 receptor antagonists, and an opioid ligand at different stimulation parameters in neurogenic inflammation in the rat. 985 52
The effects of opioids on cigarette smoke-induced plasma exudation were investigated in vivo in the main bronchi of anesthetized guinea pigs, with Evans blue dye as a plasma marker. Acute inhalation of cigarette smoke increased plasma exudation by 216% above air control values. Morphine, 0.1-10 mg/kg but not 30 mg/kg, inhibited the exudation but had no significant effect on
substance P
-induced exudation. Both 10 and 30 mg/kg of morphine increased exudation in air control animals, an effect inhibited by antihistamines but not by a
tachykinin
neurokinin type 1-receptor antagonist. Naloxone inhibited all morphine responses. Cigarette smoke-induced plasma exudation was inhibited by a mu-opioid-receptor agonist (
DAMGO
) but not by agonists at delta (DPDPE)- or kappa (U-50488H)-receptors. None of these agonists affected exudation in air control animals. DPDPE prevented the inhibition by
DAMGO
of cigarette smoke-induced plasma exudation, and the combination of
DAMGO
and DPDPE increased exudation in air control animals. Prevention of inhibition and the combination-induced increase were inhibited by antihistamines or the mast cell-stabilizing drug sodium cromoglycate. U-50488H did not alter the response to either
DAMGO
or DPDPE. We conclude that, in guinea pig main bronchi in vivo, mu-opioid-receptor agonists inhibit cigarette smoke-induced plasma exudation via a prejunctional mechanism. Plasma exudation induced by mu- and delta-receptor interactions is due to endogenous histamine release from mast cells.
...
PMID:Effects and interactions of opioids on plasma exudation induced by cigarette smoke in guinea pig bronchi. 1007 Jan 1
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