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)

Preprotachykinin B (PPT-B) contains two peptide sequences which are flanked by pairs of dibasic amino acids: the decapeptide neurokinin B and a 30 amino acid non-tachykinin peptide consisting of the amino acids 50-79 of PPT-B. Whereas the existence of neurokinin B is well established in brain and peripheral tissues, native PPT-B(50-79) has not been identified so far. We have previously studied the distribution of PPT-B(50-79)-immunoreactivity in the rat brain using antibodies directed against synthetic PPT-B(50-79). Now we adapted a radioimmunoassay for characterizing neurochemically PPT-B(50-79)-immunoreactivity in the rat. In the brain concentrations ranging from 2 to 180 fmol/mg wet tissue weight were measured using synthetic PPT-B(50-79) as standard. The highest concentrations were observed in the interpeduncular nucleus and in the hypothalamus (180 and 90 fmol/mg tissue, respectively). Intermediate concentrations (15 to 60 fmol/mg tissue) were present in cortical areas, in the hippocampus, the spinal cord and in the olfactory bulb. Modest levels were detected in the cerebellum. Considerably lower concentrations of PPT-B(50-79)-immunoreactivity were observed in peripheral tissues. They were highest in the adrenal medulla and in the urinary bladder (3.0 and 1.2 fmol/mg tissue, respectively). This distribution, as observed by radioimmunoassay, correlated to that previously revealed by immunocytochemistry. Tissue concentrations of total PPT-B(50-79) immunoreactivity, however, were slightly higher than those of neurokinin B. Gel filtration chromatography on Sephadex G50 and reversed phase HPLC revealed at least three PPT-B(50-79) immunoreactive peaks. About 90% of the PPT-B(50-79)-immunoreactivity was contained within 2 peaks of apparently higher molecular weight than PPT-B(50-79). A minor portion of PPT-B(50-79)-immunoreactivity comigrated with the synthetic peptide, suggesting that only minor amounts of PPT-B(50-79) are formed in vivo. The processing enzyme(s) cleaving protachykinin B at the pair of basic amino acids (Lys80-Arg81) located between PPT-B(50-79) and neurokinin B may not be acting at the Arg48-Arg49 site (followed by -Leu50) at the amino terminal end of PPT-B(50-79).
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PMID:Neurochemical characterization of preprotachykinin B(50-79) immunoreactivity in the rat. 765 92

Neurons expressing preprotachykinin A and preprotachykinin B, which are the precursor prepropeptides of substance P and neurokinin B (neuromedin K), respectively, were characterized immunocytochemically in the rat neocortex. Antibodies raised against C-terminal portions of preprotachykinins were used for labeling cell bodies of preprotachykinin-producing neurons. Neurons immunoreactive for preprotachykinin B were encountered four times more frequently in the neocortex than those immunoreactive for preprotachykinin A. Preprotachykinin A-immunoreactive neurons were scattered more frequently in the deep cortical layers (layers IV-VI) than in the superficial layers (layers I-III), whereas preprotachykinin B-immunoreactive neurons were distributed more frequently in the superficial layers than in the deep layers. Almost all preprotachykinin-expressing neurons were immunoreactive for GABA, suggesting that they were non-pyramidal cells. However, co-expression of the two preprotachykinin immunoreactivities in single neurons was not found. Preprotachykinin-expressing neocortical neurons were further examined with markers for subpopulations of GABAergic cortical neurons. Immunoreactivities for parvalbumin, calbindin and somatostatin were found in 69%, 27% and 11%, respectively, of preprotachykinin A-immunoreactive neurons. Conversely, preprotachykinin A-immunoreactive neurons constituted only 6% of parvalbumin-immunoreactive neurons, 4% of calbindin-immunoreactive neurons and 1% of somatostatin-immunoreactive neurons. Immunoreactivities for calretinin, choline acetyltransferase, vasoactive intestinal polypeptide, corticotropin-releasing factor and cholecystokinin were detected in 13-39% of preprotachykinin B-immunoreactive neurons. Preprotachykinin B immunoreactivity was seen in 33% of calretinin-positive neurons, 45% of cholinergic neurons, 47% of vasoactive intestinal polypeptide-positive neurons, 59% of corticotropin-releasing factor-positive neurons and 83% of cholecystokinin-positive neurons. These results indicate that preprotachykinin A- and preprotachykinin B-expressing neurons constitute separate populations of GABAergic non-pyramidal neurons in the neocortex. Since receptors for substance P and neurokinin B are expressed in GABAergic neurons [Kaneko T. et al. (1994) Neuroscience 60, 199-211] and pyramidal neurons [Ding Y. Q. et al. (1996) J. comp. Neurol. 364, 290-310], respectively, cortical neurons may use two separate lines of tachykinin signals; substance P serves as a signal between GABAergic non-pyramidal neurons, whereas neurokinin B acts as a signal of GABAergic neurons to pyramidal neurons.
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PMID:Characterization of neocortical non-pyramidal neurons expressing preprotachykinins A and B: a double immunofluorescence study in the rat. 969 16