Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of activating the beta-adrenoceptor pathway on calcium current (ICa) in rabbit portal vein (PV) were studied in myocytes freshly isolated by collagenase and elastase treatment. ICa was measured at room temperature (20 degrees C) using whole cell, voltage-clamp methods from a holding potential of -60 mV in cells dialyzed with a pipette solution containing (mM) 100 CsCl, 20 tetraethylammonium chloride, 5 NaCl, 5 MgATP, 20 N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES), and 10 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA). The cells were superfused with a solution containing (mM) 140 NaCl, 5 KCl, 1 MgCl2, 5 CaCl2, 10 HEPES, and 10 glucose. Only L-type ICa was present in these myocytes, averaging 3.5 +/- 0.3 pA/pF at +10 mV under control conditions. With 0.1 mM guanosine 5'-triphosphate (GTP) added to the pipette solution, 1 microM isoproterenol (Iso) or forskolin (Fsk) uniformly increased ICa: Iso by 45 +/- 5% and Fsk by 88 +/- 11%. This augmentation of ICa was not associated with significant changes in the voltage dependence of activation or inactivation but was associated with a small increase in the rate of inactivation of ICa. Fsk was also associated with an increased rate of ICa activation. The Iso effect was blocked by pretreatment with 1 microM propranolol and reversed by propranolol after Iso exposure. The ICa response to 10 microM Iso or Fsk was smaller than the response to 1 microM, with some cells showing a steady-state reduction in ICa. When the latter occurred, the voltage dependence of availability was shifted to the left by 5 +/- 0.4 mV.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:GTP requirement for isoproterenol activation of calcium channels in vascular myocytes. 763 49

Altered function of smooth muscle cell K+ channels have been reported in hypertension, but the contribution of various K+ channel types to these changes has not been completely determined. The purpose of this study was to compare the contribution of K+ channel types to whole cell K+ currents recorded from isolated thoracic aorta myocytes of 13 to 15 week old Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Cells were isolated by collagenase and elastase digestion, and K+ currents recorded using whole cell voltage clamp methods at room temperature. Cells were superfused with a solution containing (in mmol/ L) 140 NaCl, 5 KCl, 2 CaCl2, 1 MgCl2, 10 HEPES, and 10 glucose. Pipettes were filled with a solution containing (in mmol/L) 120 KCl, 5 NaCl, 5 MgATP, 20 HEPES, and 10 BAPTA. The K+ currents (IK) recorded from a holding potential (HP) of -80 mV were smaller in the SHR compared to those in WKY (for example, at 20 mV: WKY = 6.1 +/- 0.6 pA/pF and SHR = 3.7 +/- 0.2 pA/pF). Values of cell capacitance were not different between the two groups (WKY = 25.2 +/- 3.2 pF and SHR = 26.6 +/- 1.9 pF). A component of IK inhibited by voltage (Kv) over the range from -80 to -20 mV was smaller in SHR. The voltage dependence of Kv availability and activation were not significantly different between the two groups. IK recorded from a HP = -20 mV (KCa) was not different between the two groups. Difference currents calculated from IK measured at HP of -80 and -20 mV (that is, Kv) were smaller in SHR as was the fraction of IK inhibited by 4-aminopyridine. These results suggest that under conditions of low intracellular [Ca2+] there are no differences in KCa currents, but the Kv currents are smaller in SHR. Inhibition of Kv by 4-aminopyridine (0.1 to 10 mmol/L) caused larger increases in basal tone in WKY aorta. These results suggest that Kv channels contribute to resting K+ conductance in both WKY and SHR aorta, but with a relatively larger contribution in the WKY.
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PMID:Comparison of K+ channel properties in freshly isolated myocytes from thoracic aorta of WKY and SHR. 887 45

The aim of the paper was the assessment of the effect of magnesium ions on ethanol-induced changes in the content of ester-bound fatty acids in isolated rat hepatocytes and their cell membranes. Hepatocytes were isolated by means of the enzymatic method of Selgen using collagenase. The number and viability of isolated rat hepatocytes, incubated for 5 hours in culture media (Hepatocyte Medium) with ethanol and MgCl2 solutions with concentration amounting respectively to: 150 mM/dm3 of ethanol and/or 2 mM/dm3 of MgCl2, 4 mM/dm3 of MgCl2, were determined. Biochemical tests of hepatocytes were performed, consisting in the determination of the total content of ester-bound fatty acids in whole hepatocytes and their cell membranes after incubation. Confirmed normalising action of magnesium ions with respect to the effects induced in hepatocytes and their membranes by the presence of ethanol should be attributed to the important role of magnesium which it performs during reactions taking place with participation of ATP.
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PMID:Effect of magnesium ions on ethanol-induced changes in the pool of saturated, mono- and polyunsaturated fatty acids in isolated rat hepatocytes. 2324 Nov 26

Magnesium is one of the commonly used dietary supplements. Therefore, this study was to evaluate the content of short, medium and long-chain fatty acids and their esters in isolated rat hepatocytes induced by magnesium and/or ethanol. Isolation of hepatocytes was carried out by the Seglen's enzymatic method using collagenase. To thus prepared samples ethanol and/or MgCl2 solution were added, respectively, so that their concentrations were as follows: 150 mM/dm3 ethanol and/or 2 mM/dm3 MgCl2, 4 mM/dm3 MgCl2. The contents of short, medium and long-chain fatty acids and those of ester-bound acids were determined. The statistical evaluation of the experiment was made by comparing the area normalized for the analysed fatty acids in hepatocytes incubated for 5 h in the presence of the test substances. The effect of magnesium ions on the content of fatty acids and their esters in isolated hepatocytes incubated for 5 h depended on their concentration in the medium. A normalizing effect of magnesium ions on ethanol-induced changes in the content of C14-C17, C18-C20 and C21-C24 fatty acids was demonstrated. A normalizing effect of magnesium on ethanol-induced changes in the content of ester-bound fatty acids in hepatocytes was not confirmed.
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PMID:Changes in the content of short, medium and long-chain fatty acids in isolated hepatocytes incubated in the presence of magnesium ions and/or ethanol. 2438 87


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