These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Cardiac gap junctions: three distinct single channel conductances and their modulation by phosphorylating treatments.
    Author: Takens-Kwak BR, Jongsma HJ.
    Journal: Pflugers Arch; 1992 Nov; 422(2):198-200. PubMed ID: 1283218.
    Abstract:
    The effects of an increase in intracellular cyclic GMP (cGMP)-concentration on gap junctional current (Ij) were studied in cultured neonatal rat heart cells using both the whole-cell and perforated patch voltage-clamp method. In whole-cell measurements, exposure to 8-bromo-cGMP or carbachol reduced Ij. With the perforated patch technique, on the other hand, Ij was not affected by either 8-bromo-cGMP or carbachol. Addition of alkaline phosphatase prevented the carbachol-induced decrease in Ij in whole-cell measurements. Reduction of Ij in well-coupled cell pairs by application of heptanol allowed us to study the effects of these substances on the single gap junction channel level. We found that cGMP-treatment shifts the single channel conductance (gamma j) from 43 to 21 pS in whole-cell measurements and that intracellular addition of phosphatase prevents this shift. In contrast, intracellular phosphatase-treatment itself shifts gamma j to 70 pS. Our results indicate that Cx43-gap junction channels may exhibit three conductance levels (21 pS, 40-45 pS and 70 pS), depending on the phosphorylation state of the protein.
    [Abstract] [Full Text] [Related] [New Search]