Gap junctions between human corpus cavernosum smooth muscle cells: gating properties and unitary conductance

Moreno, Alonso P.; Carvalho, Antônio Carlos Campos de; Gj, Christ; Melman, Arnold; Spray, David C.

doi:10.1152/ajpcell.1993.264.1.c80

Cited by 78 publications

(33 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, the actual autonomic fiber distribution within the corpora is sparse, and neural transmission occurs not only by direct innervation of neural elements to smooth muscle, but also through cell-to-cell gap junction transmission between smooth muscle myocytes. 10 Thus, electrical activity recorded from a corpus cavernosum that was presumably denervated was likely transmitted through the erectile tissue from the corporal body with intact innervation.…”

Section: Discussionmentioning

confidence: 99%

Evoked cavernous activity: measuring penile autonomic innervation following pelvic surgery

et al. 2005

View full text Add to dashboard Cite

To assess cavernous nerve integrity, we measured evoked cavernous activity (ECA) in 16 men who underwent nerve sparing radical prostatectomy (NS group) and 11 men who underwent non-nervesparing surgery (non-NS group). The right median nerve was electrically stimulated and ECA was recorded with two concentric electromyography needles placed into the right and left cavernous bodies. We simultaneously recorded hand and foot sympathetic skin responses (SSRs) as controls. All subjects had recordable SSR, and all subjects following nerve-sparing radical prostatectomy had reproducible ECA. Of the 11 non-NS subjects, eight had no response, indicating interrupted corporal innervation. Three subjects had reproducible ECA, one of whom had a very late latency, suggesting residual innervation was present. The mean latencies of ECA were similar to foot SSR mean latencies (P40.05), but not to hand SSR latencies. The non-NS group was significantly different from the NS group for the presence of ECA (Po0.001). ECA is a viable method of evaluating the autonomic innervation of the penis.

show abstract

Section: Discussionmentioning

confidence: 99%

Evoked cavernous activity: measuring penile autonomic innervation following pelvic surgery

et al. 2005

View full text Add to dashboard Cite

show abstract

“…To this end, we studied Cx43-derived gap junction channel activity in the well-characterized cultured human corporal smooth muscle cells. 5,6,12 …”

mentioning

confidence: 99%

“…11 A subconducting state of 60 pS has also been reported. 12 These different conducting levels (sublevels) have been correlated with phosphorylation levels for Cx43. 13 The occurrence of subconductance states in gap junction channels raises two immediate questions.…”

mentioning

confidence: 99%

Analysis of the Presence and Physiological Relevance of Subconducting States of Connexin43-Derived Gap Junction Channels in Cultured Human Corporal Vascular Smooth Muscle Cells

Christ

Brink

1999

Circulation Research

View full text Add to dashboard Cite

Abstract-Subconductance states are a commonly observed feature of gap junction channels. Their overt frequency and consistent appearance in both single and multichannel records have led to speculation that they might be of physiological importance in terms of altering the rate of small solute transfer from cell to cell. Among the connexin gene family, connexin43 (Cx43) is the most ubiquitous connexin that has been shown to generate subconductive states. Therefore, it was the explicit aim of this investigation to more fully evaluate the potential contribution of human Cx43-derived subconducting states to intercellular communication in cultured human corporal vascular smooth muscle cells. To determine the weight of subconductive states in our records, we analyzed amplitude histograms of multichannel and single-channel data during the application of transjunctional voltages larger than expected for physiological conditions but still smaller than transjunctional voltages known to induce lower conductive states (V o ϾV j ). The data clearly indicated that the subconducting states occupy only a small fraction of the total channel open time. This was reflected by the fact that the average open probability for the subconductive state(s) determined from the 9 records analyzed was Ϸ2%. Closer inspection of the data revealed that the frequency of subconductive states was actually higher than the frequency of the main state conductance. In summary, recording conditions sufficient for evaluation of the intrinsic gating characteristics of human Cx43-derived gap junction channels have been used. Under these conditions, our data clearly indicate that despite their greater frequency, the duration of subconductance events is so short relative to the main state duration as to render them physiologically insignificant. These different conducting levels (sublevels) have been correlated with phosphorylation levels for Cx43. 13 The occurrence of subconductance states in gap junction channels raises two immediate questions. First, are the selectivity characteristics of the substates the same as or different from the main state? Second, do the substates play a role in the voltage-dependent processes of gap junctions? Recent studies 11 showed that one subconductance state for Cx43 was more restrictive than the main state by Ϸ50%, but the data also indicated that, as documented for the main state, the subconducting state was still permeable to both cations and anions. Further, it has been argued that the substates of Cx43 are less voltage dependent than the main state and thus comprise a large portion of the steady-state conductance observed with large V j gradients. 14 For hCx37 this is clearly the case. 15 A third question arises as well. Is the frequency or dwell time of the subconducting states sufficient to be of significance with regard to affecting junctional conductance or permeation of intercellular messengers when V j is in the voltage-independent portion of the G j /V j relationship (ie, V j stepsϽV o )? This last case question...

show abstract

“…Subconductance states have been reported for several other connexin gap junction channels (29,34,35,50), but the gating and conductive states (for both the main state and subconductive state) as well as the G j -V j relationship reported in the present study are consistent with Cx43 behavior (3,35,40,51,53,55,56). The mean open and closed times reported in the present study, which result in an open probability near 80%, are also hallmarks of Cx43-derived gap junction channels and are similar to those biophysical characteristics previously described for Cx43 in human corporal smooth muscle, saphenous vein, and internal mammary artery (3,35,53). That is, the mean values for all of the Boltzmann parameters, as well as the single-channel conductance values (for both the main state and substate) reported for human detrusor myocytes, are virtually indistinguishable from the values previously reported in these same three physiologically distinct human smooth muscle cell types (see Table 1).…”

Section: Discussionmentioning

confidence: 99%

Gap junction channel activity in short-term cultured human detrusor myocyte cell pairs: gating and unitary conductances

Wang

Brink²,

Christ³

2006

American Journal of Physiology-Cell Physiology

View full text Add to dashboard Cite

. Gap junction channel activity in short-term cultured human detrusor myocyte cell pairs: gating and unitary conductances. Am J Physiol Cell Physiol 291: C1366 -C1376, 2006. First published August 9, 2006 doi:10.1152/ajpcell.00027.2006.-Several independent lines of investigation indicate that intercellular communication through gap junctions modulates bladder physiology and, moreover, that altered junctional communication may contribute to detrusor overactivity. 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. Northern and Western blots were used to identify connexin expression in frozen human bladder tissue and short-term cultured human detrusor myocytes. Double whole cell patch (DWCP) recording revealed that human detrusor myocyte cell pairs were well coupled with an average junctional conductance of 6.5 Ϯ 4.6 nS (ranging from 0.1 to 15 nS, n ϭ 22 cell pairs). Macroscopic gap junction channel currents in human detrusor myocytes exhibited voltage dependence similar to homotypic connexin43. The normalized transjunctional conductance-voltage (G j-Vj) relationship was symmetrical and well described by a two-state Boltzmann relation (G min Ϸ 0.33, V 0 ϭ 63.6 mV, Z ϭ 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 ϳ120 pS for the fully open channel and ϳ26 pS for the major substate. Occasionally, other subconductance states were also observed. The single-channel mean open time 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. bladder function; intercellular communication; smooth muscle

show abstract

Gap junctions between human corpus cavernosum smooth muscle cells: gating properties and unitary conductance

Cited by 78 publications

References 1 publication

Evoked cavernous activity: measuring penile autonomic innervation following pelvic surgery

Evoked cavernous activity: measuring penile autonomic innervation following pelvic surgery

Analysis of the Presence and Physiological Relevance of Subconducting States of Connexin43-Derived Gap Junction Channels in Cultured Human Corporal Vascular Smooth Muscle Cells

Gap junction channel activity in short-term cultured human detrusor myocyte cell pairs: gating and unitary conductances

Contact Info

Product

Resources

About