Table 1.
Coupling efficiency and junctional conductance of innexin-expressing Xenopus oocyte pairs
|
Oocyte injection (cell 1/cell 2) |
Mass injected (ng/cell) |
Proportion of cells displaying coupling (%) |
n |
Maximum steady-state conductance of gap junction (μS) |
|---|---|---|---|---|
| Hm-inx1/Hm-inx1 | 10 | 25 | 36 | 4.06 ± 1.18 (9) |
| Hm-inx2/Hm-inx2 | 10 | 48 | 27 | 1.70 ± 0.49 (13) |
| Hm-inx1/Hm-inx2 | 10 | 44 | 18 | 1.54 ± 0.53 (8) |
| Dm-shakB(lethal)/Dm-shakB(lethal) | 2 | 77 | 13 | 13.19 ± 2.99 (10) |
| H2O/H2O |
N/A |
0 |
30 |
0.11 ± 0.04 (30) |
Oocytes were microinjected with an antisense Cx38 oligonucleotide and either innexin mRNA or water. The vitelline membrane was then removed, and oocytes were paired (see Materials and Methods). Recordings were made 2-6d after pairing using the dual voltage-clamp technique. Junctional conductance is shown as the maximum steady-state conductance observed, expressed as a mean ± SEM (number in parentheses indicates the number of cell pairs analyzed). Maximum conductance was observed on injection of a low depolarizing voltage step (homotypic Hm-inx1 and Dm-shakB(lethal)), a low hyperpolarizing voltage step (homotypic Hm-inx2), or a large hyperpolarizing step injected into the Hm-inx2-expressing cell (heterotypic junctions), as shown in the Gj/Vj plots (Figs. 5B, 6B, 7C).