Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interneurons from the CA1 lacunosum-moleculare (L-M) region were isolated by trypsin-hyaluronidase treatment and mechanical trituration of the L-M. Interneurons isolated in this manner were multipolar with several dendritic processes and could be distinguished from CA1 pyramidal neurons. The properties of a low-threshold transient (LTT) Ca2+ current were investigated using whole-cell voltage-clamp techniques. The activation threshold of the LTT Ca2+ current was -60 mV, and the peak current, 100 +/- 9 pA (mean +/- SEM; n = 15), was observed at -30 mV. Ca2+ was the predominant charge carrier because the current was not affected by tetrodotoxin and was abolished in Ca(2+)-free external solution. Steady state inactivation was observed when the holding potential was positive to -100 mV, and the current was half-inactivated at -84 mV. Complete inactivation occurred at a holding potential of -60 mV. The time-to-peak of the current was highly voltage dependent and ranged from 10 msec at -60 mV to 4 msec at 0 mV. The time constant of inactivation was also voltage dependent and ranged from 27 msec at -60 mV to 12 msec at greater than -30 mV. Recovery from inactivation to 90% of maximum current occurred within 200 msec. L-M interneurons receive synaptic inputs from the septum that release ACh or GABA and from the raphe nuclei that release 5-HT. Carbachol, a nonhydrolyzable cholinergic agonist, and 5-HT quickly and reversibly increased the amplitude of the LTT Ca2+ current. Carbachol's actions were blocked by atropine, indicating that this effect was mediated by muscarinic receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Low-threshold transient calcium current in rat hippocampal lacunosum-moleculare interneurons: kinetics and modulation by neurotransmitters. 167 22

1. Serotonin stimulated the incorporation of 32P from [gamma-32P] ATP into crude membrane preparations (P2) of Hymenolepis diminuta in a dose-dependent manner (EC50 of approximately 0.79 microM). 2. This response was seen with several serotonin agonists, and was inhibited by several serotonin antagonists, which were identical to the previously described activation and inhibition of serotonin-sensitive adenylate cyclase. 3. Cyclic AMP produced a dose-dependent stimulation of 32P incorporation into the P2 fraction, with an EC50 of approximately 2.51 microM. 4. The targets for the serotonin stimulated incorporation of 32P were found to be in trypsin-labile proteins with Mr's of 134,000, 110,000, 82,000, 80,000 and 31,000.
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PMID:Serotonin stimulates protein phosphorylation in the cestode Hymenolepis diminuta. 168 44

The diversity of biologically active molecules produced by vascular endothelium suggests that the endothelial cell is an active participant in numerous physiological responses, including those of the immune system. In fact, the accumulation of T lymphocytes at extralymphatic inflammatory foci represents a series of interactions between lymphocytes and vascular endothelial cells. These interactions, however, may be modulated by other factors, such as vasoactive amines. In the current study, we report that serotonin-stimulated cultured bovine aortic endothelial cells (BAECs) secrete a T-lymphocyte chemotactic cytokine (endothelial cell-derived lymphocyte chemotactic activity [ED-LCA]). Supernatants from BAECs incubated with 10(-7)-10(-4) M serotonin (5-hydroxytryptamine [5-HT]) enhanced T-cell migration, which peaked at 10(-5) M 5-HT (235 +/- 18% control migration). ED-LCA was not stored in an active form in BAECs; its secretion occurred within 60 minutes of exposure to 5-HT and was blocked by two different 5-HT2 receptor antagonists. ED-LCA was not secreted after exposure of BAECs to histamine or angiotensin II, nor was it secreted by either 5-HT-stimulated bovine pulmonary arterial or human umbilical vein endothelial cells. Physicochemical characterization of ED-LCA demonstrated that it was a trypsin-sensitive protein with an apparent molecular mass of 13-15 kDa. Preparative isoelectric focusing demonstrated pIs of 6.0 and 7.5. When applied to a molecular sieve column, the chemotactic activity corresponding to these pIs eluted in the region of 13-15 kDa. Further investigation demonstrated that partially purified ED-LCA was specific for CD4+ and CD8+ T-lymphocyte subsets and did not enhance the migration of neutrophils or monocytes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Restricted secretion of a T-lymphocyte chemotactic cytokine by serotonin-stimulated cultured aortic endothelial cells. 186 Jan 74

Specific and localized lesions of the 5-HT fibers in the hippocampus induce homotypic collateral sprouting and enhance serotonergic fiber outgrowth from adult neurons and transplanted fetal tissue. In this study, hippocampal extracts were prepared and applied to primary cultures of fetal serotonergic neurons. The effects of plating density and serum additives were examined. The growth of the serotonergic neurons in the rostral brainstem dissociated cultures were estimated by measuring the specific uptake of [3H]5-HT. The results indicate the presence of a trypsin-sensitive factor which is active when prepared fresh at dilutions up to 1/10,000. The factor is higher in hippocampus than cerebellum. Young male tissue contained more activity than either female or aged hippocampus. Although both positive and negative effects are described, higher dilutions of factor (1/1,000) were generally stimulatory in high density cultures while lower dilutions (1/10) were inhibitory in low density cultures. Specific removal of 5-HT hippocampal afferents with fornix-fimbria microinjections of 5,7-dihydroxytryptamine resulted in an initial loss of activity (2 days and 2 weeks) followed by an enhanced activity (2 months) compared to normal hippocampal extract. Several possibilities are discussed as to the identity of the serotonergic growth factor from hippocampal supernatant.
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PMID:Activity of hippocampal extract on development of [3H]5-HT high-affinity uptake in dissociated microcultures. 192 81

Exposure of bovine pulmonary artery smooth muscle cells (SMC) to anoxia for 24 h resulted in an approximate twofold stimulation of serotonin (5-HT) uptake compared with SMC exposed to 20% O2. The stimulation of 5-HT uptake by exposure to anoxia was eliminated when bovine pulmonary artery endothelial cells (EC) were cocultured with SMC. Incubation with EC-conditioned medium produced similar inhibitory effects on 5-HT uptake of SMC exposed to anoxia, a result not seen with SMC-conditioned medium. The inhibitory effect of EC-conditioned medium on the anoxia-stimulated 5-HT uptake was concentration dependent and absent at a dilution of 1:16. The production of the inhibitor was time-dependent. The EC-derived inhibitory factor was heat-stable at 100 degrees C for as long as 10 min and was stable in a pH range from 5.0 to 10.0. Significant losses of inhibitory activity of EC-conditioned medium were observed after treatment with trypsin, pronase E, and proteinase K. The molecular weight on the inhibitory factor from EC-conditioned medium was estimated to be approximately 66,000 by size-exclusion chromatography. The data show that stimulated uptake of 5-HT by SMC under anoxic conditions is under regulation by a protein (or polypeptide) produced by EC.
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PMID:Endothelial cell inhibition of hypoxia-induced stimulation of serotonin uptake by vascular smooth muscle cells. 271 40

It is known that platelet MAO appears to behave more like the B-form enzyme than the A-form enzyme based on inhibitor sensitivity and substrate specificity. However, dog platelets showed a different substrate specificity such as high activity with 5-HT and beta-PEA as substrates. Moreover, dog platelet MAO was sensitive to the drugs clorgyline and harmaline with 5-HT as the substrate, while it was sensitive to the drug deprenyl with beta-PEA as the substrate. These results also indicate the existence of two forms of MAO in dog platelets unlike in other platelets such as those from humans. A-form MAO from dog platelets was more stable against heat treatment at 55 degrees C than A-form MAO from dog liver and brain. On the other hand, there was no difference in the heat resistance of the three enzymes with beta-PEA as the substrate. After digestion with trypsin at 37 degrees C for 30 min, it was found that MAO from dog platelets, brain and liver were mostly inhibited with 5-HT as the substrate. In contrast, MAO in brain and liver were inhibited about 10%, but platelet MAO was inhibited about 50% with beta-PEA as the substrate. From these results, it is considered that dog platelet MAO exists as the two forms of the enzyme and has different enzymic properties in comparison with those of MAO from dog liver and brain mitochondria.
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PMID:Evidence for existence of A and B form monoamine oxidase in mitochondria from dog platelets. 311 4

1. Experiments designed to elucidate the role of Ca in the excitation-contraction coupling of the anterior byssus retractor muscle (ABRM) were carried out. Ca influences membrane depolarization and provides for coupling of the contraction in response to repetitive electrical stimulation as well as of ACh and KCl contracture. Depriving ABRM of Ca results in two closely correlated events: disappearance of action potential and of the contraction in response to repetitive electrical stimulation.2. A sigmoid increase in tension with the log-Ca concentration in artificial medium was observed whereas, over the same range of concentrations, the tension remnant decreased.3. Induction of relaxation by 5-HT is Ca dependent. Either thiourea inactivation or Ca deprivation results in failure to relax. Low concentrations of 5-HT (10(-7) g/ml.) bring about increase in peak tension of the contraction in response to repetitive electrical stimulation, whereas higher concentrations (10(-5) g/ml.) undermine peak tension.4. Frequencies exceeding 40 cycles evoke a contraction accompanied by tension remnant, which is eliminated with 5-HT.5. Dropwise addition of Ca on a trypsin window in the muscle induces a latency relaxation before onset of Ca-contracture.
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PMID:Ca-coupling in the anterior byssal retractor muscle of Mytilus edulis L. 605

Basal and modulated secretion of ACTH and lipotropin (LPH) by cultures of trypsin-dispersed cells of a biopsy of a human corticotropic adenoma have been examined. ACTH secretion was detectable throughout the period of culture (13 days) but declined steadily from an initial production rate of 238 +/- 124 ng/3 X 10(5) cells/12 h. The time course of secretion showed a slower phase over the first 4 h, with increases up to 12 h. An extract of rat stalk median eminence caused a significant (P less than 0.005) dose-dependent increase in both ACTH and LPH secretion during 30 min. The patterns of response for ACTH and LPH were very similar; both exhibited a decline in the basal release of peptide subsequent to the period of stimulation. The addition of hydrocortisone (0.2 micrograms/ml) did not suppress basal ACTH secretion during 30 min but significantly (P less than 0.05) inhibited stimulation produced by rat stalk median eminence extract. Arginine vasopressin (dose range, 1-9 ng/ml) significantly (P less than 0.025) stimulated both ACTH and LPH secretion during 30 min. The patterns of response were again very similar. Serotonin (dose range, 0.01-10 micrograms/ml) did not affect ACTH secretion during incubations of 30 min to 4 h. The results obtained with the cell cultures of a human corticotropic cell adenoma concur with in vivo findings of incomplete autonomy of secretion, parallel secretion of ACTH and LPH in response to provocative stimuli, and suppression by corticosteroids. The technique has potential for exploring the cellular mechanisms controlling secretion by human corticotropic adenomas as well as the nature of the hormones produced.
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PMID:Adrenocorticotropin and lipotropin secretion by dispersed cell cultures of a human corticotropic adenoma: effect of hypothalamic extract, arginine vasopressin, hydrocortisone, and serotonin. 625 Nov 5

To elucidate the mechanism by which palate shelves reorient during embryogenesis, migration of palate mesenchymal cells has been studied employing various substrates. When palate explants were cultured in a hydrated collagen lattice, it was observed that bipolar spindle-shaped cells migrated out of each explant toward the other. These cells were aligned parallel to each other and to the fibrous tracks that formed. The cells appeared to move along and through the fibrous tracks. Cell migration was dependent on the presence of serum and fibronectin. The fibrous tracks viewed by phase microscopy were sensitive to collagenase. Scanning electron microscopy revealed that the collagen fibers of the hydrated lattice had coalesced into larger bundles. Pretreatment of explants with serotonin stimulated cell migration out of the explant into the hydrated collagen lattice. This effect was specific, since the antagonist methysergide blocked the stimulation produced by serotonin. Employing other substrates, it was noted that palate cells migrating out of double explants toward each other produced large wrinkles in a polysiloxane substratum. Similarly, cultured monolayer cells also produced wrinkles that disappeared as cells rounded up after trypsin treatment. Finally, monolayer cells pulled on and distorted collagen films when cultured on the substrate. It is concluded that migrating palate cells can interact with their substrate producing tractional forces. Serotonin-induced modulation of cell motility and its relationship to palate reorientation are discussed.
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PMID:Palate cell motility and substrate interaction. 635 29

A bradykinin (BK)-like substance (P1) in the rat stomach was extracted with acetic acid, n-butanol, distilled water and methanol. The gradient and equilibrium chromatography were carried out on SP-Sephadex C-25 columns with the extract containing P1. P1 had a different retention time from BK, kallidin and methionyl-lysyl-bradykinin (MLBK), on the equilibrium chromatography. The apparent molecular weight of P1 estimated by gel chromatography was over 1,300. P1 was classified as a biologically BK-like peptide of mammalian origin which is distinct from BK, kallidin and MLBK. Another kind of biologically active substance (P2) which contracts the isolated rat uterus and duodenum was detected during the course of the extraction and purification of P1. The contractile activity of P2 was abolished by the presence of dibenamine or methysergide, but was not influenced by chymotrypsin, trypsin or papain digestion. The hypotensive effect of P2 on rabbit blood pressure was similar to that of serotonin (5-HT). The retention times of P2 on the equilibrium chromatography on the SP-Sephadex C-25 column, and on the gel chromatography were the same as those of 5-HT. P2 proved to be 5-HT.
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PMID:A bradykinin-like substance in rat stomach. 720 76


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