Characterization of gap junctions between pairs of Leydig cells from mouse testis

Am J Physiol. 1994 Aug;267(2 Pt 1):C570-80. doi: 10.1152/ajpcell.1994.267.2.C570.

Abstract

Leydig cells are coupled in vivo by numerous gap junctions. In vivo and in vitro cells were immunolabeled by connexin 43 (Cx43) but not by Cx26 or Cx32 antibodies; immunoblotting confirmed specificity of Cx43 labeling. Pairs of Leydig cells dissociated from mouse testis were studied by dual whole cell voltage clamp, and a high incidence of dye (n = 20) and electrical coupling (n = 60; > 90%) was found. Coupling coefficients were near 1 and junctional conductance (gj) averaged 7.2 +/- 1.2 nS (SE, n = 40). Large transjunctional voltage (Vj) decreased gj; currents decayed exponentially with time constants of seconds that decreased at greater Vj. The residual conductance at large Vj was at least approximately 40% of the initial conductance. Exposure of cell pairs to saline solutions saturated with CO2 (n = 15) or containing 2 mM halothane (n = 15) or 3.5 mM heptanol (n = 15) rapidly and reversibly reduced gj. In eight cell pairs, gating of single junctional channels was observed during halothane-induced reduction in gj. Most gating events at Vj < 40 mV were fit by a Gaussian distribution with a mean of approximately 100 pS. With Vj > 40 mV, smaller transitions of approximately 30 pS were also recorded, and the frequency and duration of the approximately 100-pS transitions decreased. Also, approximately 70-pS transitions between 30- and 100-pS conductances were observed in the absence of 70-pS transitions to or from the baseline, indicating that the 30-pS conductance was a substate induced by large Vj.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alcohols / pharmacology
  • Animals
  • Carbon Dioxide / pharmacology
  • Cell Membrane / physiology
  • Electric Conductivity
  • Gap Junctions / physiology*
  • Halothane / pharmacology
  • Heptanol
  • Ion Channels / physiology
  • Leydig Cells / physiology*
  • Male
  • Mice
  • Mice, Inbred Strains

Substances

  • Alcohols
  • Ion Channels
  • Carbon Dioxide
  • Heptanol
  • Halothane