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Query: UNIPROT:P20366 (
substance P
)
21,176
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The fine structure of
substance P
(SP) and
adenosine deaminase
(
ADA
) immunoreactive structures in synaptic contacts localized to the superficial layers of the superior colliculus of the rat was investigated by means of immunoelectron microscopy. We also examined the possibility of retinal innervation of SP- and
ADA
- containing neurons by immunohistochemistry after degeneration of retinal terminals caused by enucleation. SP-like immunoreactive presynaptic terminals of the stratum griseum superficiale (SGS) formed both asymmetric and symmetric synaptic contacts. Presynaptic dendritelike structures were also observed. SP immunoreactive postsynaptic elements made contacts with terminals showing diverse features.
ADA
-like immunoreactive structures were seen only as postsynaptic elements to different kinds of nonimmunoreactive terminals and were mostly localized in the ventral third of the SGS and the dorsalmost stratum opticum (SO). After enucleation, degenerating retinal terminals were found to form synaptic contacts with SP and
ADA
immunoreactive structures. The highest number of such degenerating terminals on
ADA
immunoreactive structures was observed 2 days after retinal denervation, very few being seen after 5 days. These degenerating terminals were restricted to the ventral SGS and dorsal SO. SP immunoreactive structures postsynaptic to degenerating retinal terminals were most numerous 5 days after enucleation and mainly localized in the dorsal SGS. Occasionally, SP immunoreactive dendritelike processes forming synapses with degenerating retinal terminals were simultaneously presynaptic to other nonimmunoreactive profiles, defining, therefore, serial synapses. The present results suggest that SP-I and
ADA
-I collicular neurons may be part of distinct channels carrying visual information to the lateral posterior and lateral geniculate nuclei of the thalamus, respectively.
...
PMID:Fine structure of synapses and retinal innervation of substance P and adenosin deaminase containing neurons in the superior colliculus of the rat. 170 66
The distribution of
adenosine deaminase
-containing neurons and fibers in the spinal cord and medulla was examined and the relationship of dorsal root ganglia neurons containing this enzyme to those containing somatostatin,
substance P
, fluoride-resistant acid phosphatase (FRAP) and 5'-nucleotidase was determined using immunohistochemical and histochemical methods. In the spinal cord
adenosine deaminase
-immunoreactive fibers and neurons were confined to layer I and IIo. A similar localization of these was observed in the spinal trigeminal nucleus. In adult animals treated neonatally with capsaicin
adenosine deaminase
-positive fibers were totally depleted in layer IIo but only partially depleted in layer I. Analysis of lumbar sensory ganglia revealed that small type-B neurons immunoreactive for
adenosine deaminase
were also immunoreactive for somatostatin but not
substance P
. In addition,
adenosine deaminase
-positive neurons lacked histochemical reaction-product for FRAP and exhibited the lowest activity of 5'-nucleotidase. Examination of the neuronal populations containing the two phosphatase enzymes showed that a proportion of neurons exhibiting 5'-nucleotidase activity were devoid of FRAP activity. It is concluded that dorsal root ganglia neurons immunoreactive for
adenosine deaminase
and somatostatin constitute a single subpopulation of type-B ganglion cells separate from those containing
substance P
or FRAP. It appears that the lack of coexistence of
adenosine deaminase
with either FRAP or 5'-nucleotidase cannot be attributed simply to a coexistence of the two latter enzymes since some 5'-nucleotidase-positive neurons lacking FRAP were also devoid of
adenosine deaminase
-immunoreactivity. Insofar as these three enzymes may contribute to the regulation of transmission processes in primary sensory neurons, our results indicate a minimal functional relationship between adenine nucleoside and nucleotide degrading enzymes in these neurons. In addition, FRAP appears to have some functional independence from 5'-nucleotidase.
...
PMID:Anatomical and cytochemical relationships of adenosine deaminase-containing primary afferent neurons in the rat. 241 72
The distribution and morphology of
adenosine deaminase
,
substance P
, leucine-enkephalin, corticotropin-releasing factor, and calcitonin gene-related peptidelike immunoreactive cells and fibers throughout the superior colliculus of the rat were examined by means of the unlabelled-antibody peroxidase-antiperoxidase method. Adenosine deaminase immunoreactive cells were found in the stratum opticum and lower stratum griseum superficiale;
substance P
immunoreactive cells were localized to the upper stratum griseum superficiale, and calcitonin gene-related peptide immunolabelled neurons were situated in deeper strata.
Substance P
, leucine-enkephalin, and calcitonin gene-related peptide immunoreactive fibers were distributed similarly in their lamination and in their patchlike organization. Corticotropin-releasing factor immunoreactive fibers were observed evenly throughout all the strata and were fewer in the stratum griseum superficiale. These findings suggest that, as in afferent modules and segregated efferents of the mammalian superior colliculus, the cells and fibers containing neuroactive substances and neuroactive substance-related enzymes also show a segregated and laminar distribution.
...
PMID:Laminar and segregated distribution of immunoreactivities for some neuropeptides and adenosine deaminase in the superior colliculus of the rat. 246 26
The restriction fragment length polymorphisms (RFLPs) associated with neuropeptide Y (NPY) and somatostatin loci were used to assess the possibility of linkage to a locus for affective disorder (AD). When somatostatin haplotypes were assigned to members of 2 AD pedigrees under either rare dominant or recessive transmission, the LOD scores obtained at 0% recombination were inconsistent with linkage. Similar results were obtained with NPY under rare dominant inheritance. Comparison of the frequency of the genotypes deduced from the polymorphic alleles of gastrin-releasing peptide, NPY, somatostatin and
substance P
in normals vs patients with either AD or schizophrenia suggests the absence of association. The difference in the frequency of the 3.3 kb
adenosine deaminase
fragment in normals vs bipolar and schizophrenic patients is of borderline significance.
...
PMID:Neuropeptide gene polymorphisms in affective disorder and schizophrenia. 289 62
As shown on cultured astrocytes from the mouse, in the presence of
adenosine deaminase
, 2-chloroadenosine by acting on A1-adenosine receptors potentiated the activation of phospholipase C induced by the alpha 1-adrenergic agonist, methoxamine. This potentiation required the presence of external calcium and was blocked by pertussis toxin. Moreover, this potentiation resulted from a cascade of events: activation (by calcium and protein kinase C) of a phospholipase A2 coupled to A1-adenosine receptors, release of arachidonic acid, which inhibited the reuptake of glutamate into astrocytes and finally additional activation of phospholipase C by externally accumulated glutamate through metabotropic receptors. The effects of 2-chloroadenosine and methoxamine were respectively mimicked by somatostatin and
substance P
while endothelins reproduced the combined effects of 2-chloroadenosine and methoxamine. Conditioned media from treated astrocytes enriched in glutamate stimulated phospholipase C in cultured striatal neurones. In addition, glutamate alone was also found to stimulate phospholipase A2 in astrocytes through receptors exhibiting a pharmacological profile distinct from metabotropic receptors coupled to phospholipase C and the glutamate response was potentiated by ATP. Moreover, the neuronal arachidonic acid production evoked by glutamate was potentiated by acetylcholine. Finally, the combined application of 2-chloroadenosine and methoxamine on striatal astrocytes reduced the permeability of gap junctions between astrocytes and this response was mimicked by arachidonic acid. Together, these results emphasized the contribution of astrocytes in the regulation of glutamatergic transmission.
...
PMID:Glial receptors and their intervention in astrocyto-astrocytic and astrocyto-neuronal interactions. 792 48
Non-adrenergic, non-cholinergic (NANC) nerve stimulation results in excitation (e.j.p., rebound depolarization, contractions) or inhibition (i.j.p., afterhyperpolarization, relaxations) of the gut. NANC neuronal mechanisms participate in the maintenance of the basal tone and spontaneous activity of the gut. There are however species differences, i.e. both NANC excitation and inhibition are present in the guinea pig and only NANC inhibition in the rat intestine.
Substance P
-like neuropeptide/s are suggested to be mediators released from excitatory NANC and sensory nerves. The latter are activated by histamine and degenerated by capsaicin. There is evidence in favor of a nitric oxide-like substance rather than ATP, dopamine, GABA and neuropeptides (e.g. VIP, PHI/PHM) as the inhibitory NANC mediator in the gut. TTX, high Mg(2+)-low Ca2+ media, 3,4-diaminopyridine, dipyridamol and
adenosine deaminase
modulate NANC excitation and inhibition. The NANC excitation is more sensitive than the NANC inhibition to the action of catecholamines, reserpine, 6-hydroxydopamine, chymotrypsin, prednisolon, bacitracin, opioids, free oxygen species and low concentration of local anesthetics.
...
PMID:NANC transmission in intestines and its pharmacological modulation. 839 Nov 98
Effects of the adenosine receptor agonist 2-chloro-N6-cyclopentyl-adenosine (CCPA) on stimulation of cAMP formation by histamine, 5-hydroxytryptamine,
substance P
and forskolin were determined for enzymatically dissociated ganglia from the myenteric plexus of guinea-pig small intestine. Each of the 4 substances stimulated cAMP production. CCPA blocked the stimulation of cAMP by histamine, but not by 5-hydroxytryptamine or
substance P
. CCPA marginally suppressed stimulation by forskolin. CCPA alone suppressed basal levels of cAMP. The adenosine receptor antagonist 8-cyclopentyl-1,3-dimethylxanthine (CPT) reversed the inhibitory action of CCPA on stimulation of cAMP formation by histamine. Exposure to
adenosine deaminase
or CPT increased cAMP in the ganglia. The results are consistent with a hypothesis that stimulation of adenylate cyclase and elevation of intraneuronal cAMP in enteric neurons are steps in the signal transduction cascade for the excitatory actions of 5-hydroxytryptamine,
substance P
and histamine. They are consistent also with an original hypothesis from electrophysiologic studies which states that stimulation of adenosine A1 receptors suppresses cAMP formation and thereby slow synaptic excitation in response to histamine, but not to 5-hydroxytryptamine or
substance P
. The results support evidence from intracellular microelectrode studies which suggested that endogenous adenosine accumulates to levels sufficient for tonic suppression of cAMP formation in myenteric ganglia in vitro.
...
PMID:Suppression of cAMP formation by adenosine in myenteric ganglia from guinea-pig small intestine. 904 8
Cholinergic neurons were identified in rat striatal slices by their size, membrane properties, sensitivity to the NK(1) receptor agonist (Sar(9), Met(O(2))(11))
Substance P
, and expression of choline acetyltransferase mRNA. A(1) receptor mRNA was detected in 60% of the neurons analysed, and A(2A) receptor mRNA in 67% (n=15). The A(1) receptor agonist R-N(6)-(2-phenylisopropyl)adenosine (R-PIA) hyperpolarized cholinergic neurons in a concentration dependent manner sensitive to the A(1) antagonist 8-cyclopentyl-1, 3-dipropylxanthine (DPCPX, 100 nM). In dual stimulus experiments, the A(2A) receptor antagonist 8-(3-chlorostyryl)caffeine (CSC, 500 nM) decreased release of [(3)H]-acetylcholine from striatal slices (S2/S1 0.78+/-0.07 versus 0.95+/-0.05 in control), as did
adenosine deaminase
(S2/S1 ratio 0.69+/-0.05), whereas the A(1) receptor antagonist DPCPX (100 nM) had no effect (S2/S1 1.05+/-0.14). In the presence of
adenosine deaminase
the adenosine A(2A) receptor agonist 2-p-((carboxyethyl)phenylethylamino)-5'-N-ethylcarboxamidoadeno sin e (CGS21680, 10 nM) increased release (S2/S1 ratio 1.03+/-0.05 versus 0.88+/-0.05 in control), an effect blocked by the antagonist CSC (500 nM, S2/S1 0.68+/-0.05, versus 0.73+/-0.08 with CSC alone). The combined superfusion of bicuculline (10 microM), saclofen (1 microM) and naloxone (10 microM) had no effect on the stimulation by CGS21680 (S2/S1 ratio 0.99+/-0.04). The A(1) receptor agonist R-PIA (100 nM) inhibited the release of [(3)H]-acetylcholine (S2/S1 ratio 0.70+/-0.03), an effect blocked by DPCPX (S2/S1 ratio 1.06+/-0.07). It is concluded that both A(1) and A(2A) receptors are expressed on striatal cholinergic neurons where they are functionally active.
...
PMID:Adenosine receptor expression and function in rat striatal cholinergic interneurons. 1086 96
Membrane peptidases are a group of ectoenzymes with a broad functional repertoire. In protein metabolism, their importance is well known, especially in peptide degradation and amino acid scavenging at the intestinal and renal brush border. However, they also perform more subtle tasks; not only do they provide or extinguish signals by cleaving exterior peptide mediators, but they also may function as receptors or participate in signal transduction or in adhesion. Dipeptidyl peptidase IV (DPPIV), which is identical to the lymphocyte surface glycoprotein CD26, is unique among these peptidases because of its ability to liberate Xaa-Pro and less efficiently Xaa-Ala dipeptides from the N-terminus of regulatory peptides. It occurs in the plasma membrane as a homodimer with a total molecular mass of 22-240 KdA and the C-terminal domain probably forms on alpha/beta hydrolase fold. In addition to, but independent of its serine type catalytic activity, DPPIV binds closely to the soluble extracellular enzyme
adenosine deaminase
. The in vivo expression on epithelial, endothelial and lymphoid cells of DPPIV is compatible with a role as physiological regulator of a number of peptides that serve as biochemical reporters between and within the immune and neuroendocrine system. Surprisingly, not cytokines with a N-terminal Xaa-Pro motif, but a number of chemokines have recently been identified as substrates. Despite DPPIV mediates only a minimal N-terminal truncation, important alterations in chemokine activities and receptor specificitIes were observed in vitro together with modified inflammatory and antiviral responses. Most probably the great flexibility of the N-terminus of a number of chemokines facilitates the accessibIlity to the catalytic site of DPPIV. Other known substrates which are subject in vitro to receptor-specific changes induced by DPPIV truncation include neuropeptides such as
substance P
, peptidE YY and neuropeptide Y. On the other hand, DPPIV mediated cleavage of the N-terminal His-Ala or Tyr-Ala dipeptides from circulating incretin hormones like, glucagon-like peptides (GLP)-1 and -2, gastric inhibitory polypeptide (GIP), all members of the enteroglucagon/GRF superfamily, results in their biological inactivation in vitro and in vivo. Administration of specific DPPIV inhibitors closes this pathway of incretin degradation and greatly enhances insulin secretion. The improved glucose tolerance in several animal models for type II diabetes points to specific DPPIV inhibition as a pharmaceutical approach for type 2 diabetes drug development.
...
PMID:Peptide truncation by dipeptidyl peptidase IV: a new pathway for drug discovery? 1128 88
Hypocretins (Hcrts) are recently discovered peptides linked to the human sleep disorder narcolepsy. Humans with narcolepsy have decreased numbers of Hcrt neurons and Hcrt-null mice also have narcoleptic symptoms. Hcrt neurons are located only in the lateral hypothalamus (LH) but neither electrolytic nor pharmacological lesions of this or any other brain region have produced narcoleptic-like sleep, suggesting that specific neurons need to be destroyed. Hcrt neurons express the Hcrt receptor, and to facilitate lesioning these neurons, the endogenous ligand hypocretin-2/orexin B (Hcrt2) was conjugated to the ribosome-inactivating protein saporin (SAP). In vitro binding studies indicated specificity of the Hcrt2-SAP because it preferentially bound to Chinese hamster ovary cells containing the Hcrt/orexin receptor 2 (HcrtR2/OX(2)R) or the Hcrt/orexin receptor 1 (HcrtR1/OX(1)R) but not to Kirsten murine sarcoma virus transformed rat kidney epithelial (KNRK) cells stably transfected with the
substance P
(neurokinin-1) receptor. Administration of the toxin to the LH, in which the receptor is known to be present, eliminated some neurons (Hcrt, melanin-concentrating hormone, and
adenosine deaminase
-containing neurons) but not others (a-melanocyte-stimulating hormone), indicating specificity of the toxin in vivo. When the toxin was administered to the LH, rats had increased slow-wave sleep, rapid-eye movement (REM) sleep, and sleep-onset REM sleep periods. These behavioral changes were negatively correlated with the loss of Hcrt-containing neurons but not with the loss of
adenosine deaminase
-immunoreactive neurons. These findings indicate that damage to the LH that also causes a substantial loss of Hcrt neurons is likely to produce the multiple sleep disturbances that occur in narcolepsy.
...
PMID:Hypocretin-2-saporin lesions of the lateral hypothalamus produce narcoleptic-like sleep behavior in the rat. 1154 37
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