Details
| Originalsprache | Englisch |
|---|---|
| Seiten (von - bis) | 627-9 |
| Seitenumfang | 3 |
| Fachzeitschrift | Pflugers Archiv European Journal of Physiology |
| Jahrgang | 436 |
| Ausgabenummer | 4 |
| Publikationsstatus | Veröffentlicht - Juli 1998 |
Abstract
Hemichannels of rat connexin 46 (rCx46) were expressed in Xenopus laevis oocytes and analysed by two-electrode voltage-clamp experiments. It is established that rCx46 hemichannels can be activated at low external Ca2+ and positive membrane potentials. Upon larger depolarizations, the hemichannels of oocytes activate in a time-dependent manner, occasionally followed by a spontaneous inactivation. We found that, in the absence of inactivation, treatment of oocytes with 1-oleoyl-2-acetyl-sn-glycerol (OAG), an activator of protein kinase C (PKC), reversibly reduced the amplitude of the rCx46-mediated current and, after an incubation time of about 30 min, induced inactivation of the voltage-dependent current. After wash-out of OAG the corresponding membrane conductance increased and the inactivation behaviour disappeared. The OAG-induced inactivation, as well as the spontaneous inactivation, could be removed by application of the specific PKC inhibitor calphostin C and also by phloretin. The data provide evidence that the activation and inhibition of PKC affect the rCx46-mediated membrane conductance as well as the voltage-dependent current inactivation in an inverse manner.
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in: Pflugers Archiv European Journal of Physiology, Jahrgang 436, Nr. 4, 07.1998, S. 627-9.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - Inactivation of expressed and conducting rCx46 hemichannels by phosphorylation
AU - Ngezahayo, Anaclet
AU - Zeilinger, Carsten
AU - Todt, I.
AU - Marten, I.
AU - Kolb, Hans-Albert
PY - 1998/7
Y1 - 1998/7
N2 - Hemichannels of rat connexin 46 (rCx46) were expressed in Xenopus laevis oocytes and analysed by two-electrode voltage-clamp experiments. It is established that rCx46 hemichannels can be activated at low external Ca2+ and positive membrane potentials. Upon larger depolarizations, the hemichannels of oocytes activate in a time-dependent manner, occasionally followed by a spontaneous inactivation. We found that, in the absence of inactivation, treatment of oocytes with 1-oleoyl-2-acetyl-sn-glycerol (OAG), an activator of protein kinase C (PKC), reversibly reduced the amplitude of the rCx46-mediated current and, after an incubation time of about 30 min, induced inactivation of the voltage-dependent current. After wash-out of OAG the corresponding membrane conductance increased and the inactivation behaviour disappeared. The OAG-induced inactivation, as well as the spontaneous inactivation, could be removed by application of the specific PKC inhibitor calphostin C and also by phloretin. The data provide evidence that the activation and inhibition of PKC affect the rCx46-mediated membrane conductance as well as the voltage-dependent current inactivation in an inverse manner.
AB - Hemichannels of rat connexin 46 (rCx46) were expressed in Xenopus laevis oocytes and analysed by two-electrode voltage-clamp experiments. It is established that rCx46 hemichannels can be activated at low external Ca2+ and positive membrane potentials. Upon larger depolarizations, the hemichannels of oocytes activate in a time-dependent manner, occasionally followed by a spontaneous inactivation. We found that, in the absence of inactivation, treatment of oocytes with 1-oleoyl-2-acetyl-sn-glycerol (OAG), an activator of protein kinase C (PKC), reversibly reduced the amplitude of the rCx46-mediated current and, after an incubation time of about 30 min, induced inactivation of the voltage-dependent current. After wash-out of OAG the corresponding membrane conductance increased and the inactivation behaviour disappeared. The OAG-induced inactivation, as well as the spontaneous inactivation, could be removed by application of the specific PKC inhibitor calphostin C and also by phloretin. The data provide evidence that the activation and inhibition of PKC affect the rCx46-mediated membrane conductance as well as the voltage-dependent current inactivation in an inverse manner.
KW - Animals
KW - Connexins/antagonists & inhibitors
KW - Diglycerides/metabolism
KW - Oocytes/cytology
KW - Patch-Clamp Techniques
KW - Phosphorylation
KW - Protein Kinase C/antagonists & inhibitors
KW - Rats
KW - Xenopus laevis
U2 - 10.1007/s004240050681
DO - 10.1007/s004240050681
M3 - Article
C2 - 9683738
VL - 436
SP - 627
EP - 629
JO - Pflugers Archiv European Journal of Physiology
JF - Pflugers Archiv European Journal of Physiology
SN - 0031-6768
IS - 4
ER -