Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 348 (1993), S. 207-212 
    ISSN: 1432-1912
    Keywords: Macrophage ; Voltage-clamp ; Ionic current ; Low density lipoprotein ; Acetylated low density lipoprotein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of the present study was to search for electrophysiological effects of human lipoproteins on membrane currents in mouse peritoneal macrophages which had been cultured for 5 to 20 days. Whole-cell currents were recorded by using a voltage-clamp technique. Low density lipoprotein (LDL, 100 μg/ml) increased a slowly activating nonspecific cation current (iso) in the positive potential range to 244 ± 23% of the reference (test potential + 55 mV, n = 13, P 〈 0.005). Augmentation of current resulted out of a negative shift of the activation curve along the voltage axis (−22 mV) and an increase of maximally available current. Furthermore, LDL increased a rapidly activating outward current (ifo) at test potentials positive to the potassium equilibrium potential. At +55 mV ifo-amplitude increasedto 165 ± 14% ofreference (n = 16, P 〈 0.005). LDL-induced effects on ifo-current could be mimicked by application of the calcium ionophore A 23187 (1 μmol/l) which led to an increase of ifo-current to 161 ± 25% of the reference (test potential + 55 mV, n = 11, P 〈 0.005). Acetylated-LDL (100 μg/ml, 5–15 min) produced no significant effect on the membrane currents under investigation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 349 (1994), S. 594-601 
    ISSN: 1432-1912
    Keywords: Macrophage ; Voltage-clamp ; Potassium current ; Zymosan ; Platelet activating factor ; Calcium ionophore A 23187
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of zymosan and human serum opsonized zymosan on membrane currents of adherent mouse peritoneal macrophages which had been cultured for 5 to 20 days were investigated with the whole-cell voltage-clamp technique. Both stimuli activated an outward current. The outward current activation was transient and lasted about 5 min. In solutions with 10 or 50 mmol/l extracellular potassium concentration the activation of an outwardly directed current occurred at test potentials positive to the respective potassium equilibrium potential. This particle-induced current resembled a calciu-mactivated potassium current which could be activated with the calcium ionophore A 23187 and with platelet activating factor. The order of maximal responses (test potential +55 mV, amplitude given as percentage of the respective control) was: 0.1 μmol/l platelet activating factor (222±36%,n=8,P〈0.01) 〉 1 μmol/l A 23187 (190±24%,n=11,P〈0.01) 〉900 μg/ml opsonized zymosan (134±7%,n=22,P〈0.01) 〉900 μg/ml zymosan (116±5%,n = 21,P〈0.01) The lower efficiency of zymosan as compared to opsonized zymosan is explained in part by a lower percentage of responding cells which was 48% for zymosan and 73% for opsonized zymosan. Macrophages which were pretreated with particles showed a greater reactivity to calcium as compared to untreated cells. Elevation of extracellular calcium from 0.9 to 4.5 mmol/l activated the outward current to 145±12% (n = 11,P〈 0.01) after preincubation with opsonized zymosan and to 144±21% (n = 12,P〈 0.01) under the influence of zymosan while in untreated cells current increase by elevation of extracellular calcium was not significant (120±10%,n = 9, n.s.).
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...