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)

The presence of substance P in numerous mammalian pineal glands prompted us to search for its binding sites in the bovine pineal gland. The binding assays to pineal membrane were carried out in polypropylene microcentrifuge tubes in a final volume of 500 microliters of 50 mM Tris-HCl buffer (pH 7.4) containing aliquots of 200-500 micrograms protein, 0.02% BSA, 6 micrograms/ml chymostatin, 4 micrograms/ml leupeptin, 40 micrograms/ml bacitracin, 5 mM MnCl2, and 50 microliters of [3H]substance P (3H-SP, 45.7 Ci/mmol to yield a final concentration of 0.02-20 nM) to start the reactions, which were incubated for 20 min at 20 degrees C. The reactions were terminated by centrifugation in a Fisher Microcentrifuge Model 235A for 30 seconds at 13,000 X g, and the pellets were washed twice with 1 ml of ice-cold 50 mM Tris-HCl buffer containing 0.02% BSA, 6 micrograms/ml chymostatin, 4 micrograms/ml leupeptin, 40 micrograms/ml bacitracin, 5 mM MnCl2, 120 mM NaCl, 5 mM KCl, 1 mM MgCl2, and 1 mM CaCl2. The bottoms of the tubes were cut, the membrane pellets were dissolved in 5 ml of Triton X-100/toluene fluor (1:3) scintillation fluid, and the radioactivity was counted. The specific [3H]-substance P binding at 1-2 nM was 40-50% of the total binding, and the non-specific binding was assessed by using 2 microM of unlabelled substance P. These studies identified in bovine pineal gland a high affinity receptor site for [3H]SP with a KD value of 0.43 nM and a Bmax value of 71.14 fmol/mg protein. The relative affinity of various substance P analogues or fragments was: substance P greater than physalaemin greater than SP2-11 greater than SP3-11 greater than SP4-11 greater than SP6-11 greater than substance K = eledoisin greater than kassinin greater than SP7-11 greater than SP free acid. Substance P did not alter the basal or the norepinephrine-induced stimulation of the activity of serotonin N-acetyltransferase in rat pineal gland in culture.
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PMID:Studies on high-affinity [3H]substance P binding sites in bovine pineal gland. 243 Jul 88

Secretion of melatonin by the mammalian pineal gland is primarily regulated by the release of norepinephrine (NE) from sympathetic nerve terminals that originate from the superior cervical ganglia. Peptidergic nerves that originate in the perikarya located in the sensory trigeminal ganglia also innervate the pineal gland. Some of these peptidergic nerve fibers contain substance P. Previously, we have characterized neurokinin 1 type substance P receptors in the pineal gland. However, the function of this receptor in the pineal gland remains unclear. Here, we examined the modulatory effect of substance P on rat pineal NE transmission. We show that at the presynaptic level, substance P stimulates the KCl-induced [(3)H]NE release from the pineal nerve ending. However, we found that substance P did not affect the basal levels of either arylalkylamine-N-acetyltransferase (AANAT) activity or melatonin secretion in rat pineal organ cultures. However, in the presence of NE, substance P inhibited the NE-induced increase in AANAT activity and melatonin secretion. This is the first time that a function for substance P in the mammalian pineal gland has been demonstrated.
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PMID:The modulatory effect of substance P on rat pineal norepinephrine release and melatonin secretion. 1954 8