Several independent lines of investigation indicate that intercellular communication through gap junctions plays an important role in normal bladder physiology and bladder dysfunction. However, as far as we are aware, there are still no direct recordings of gap junction mediated intercellular currents between human or rat detrusor myocytes. Thus, Northern and Western blots were used to identify connexin expression in frozen human bladder tissue and short-term cultured human detrusor myocytes. In addition, double whole cell patch (DWCP) recording revealed that human detrusor myocyte cell pairs were well coupled with an average junctional conductance of 6.5 ± 4.6 nS (ranging from 0.1-15 nS, n=22 cell pairs). Macroscopic gap junction channel currents in human detrusor myocytes exhibited voltage dependence similar to homotypic Cx43. The normalized Gj-Vj relationship was symmetrical and well described by a two-state Boltzmann relation (G_min 0.33, V₀ = 63.6 mV, Z = 0.117 or equal to 2.95 gating charges) suggestive of a bilateral voltage-gated mechanism. In symmetric 165 mM CsCl, the measured single channel slope conductance was 120 pS for the fully open channel and 26 pS for the major substate. Occasionally, other subconductance states were also observed. The single channel mean open time (MOT) declined with increasing V_j accounting for the V_j-dependent decline of macroscopic junctional current. Qualitatively similar electrophysiological characteristics were observed in DWCP of freshly isolated rat detrusor myocytes. These data confirm and extend previous observations, and are consistent with reports in other smooth muscle cells types in which Cx43-mediated intercellular communication has been identified.