Effects of carbenoxolone on syncytial electrical properties and junction potentials of guinea-pig vas deferens.
The effects of the putative gap junction blocker carbenoxolone on smooth muscle syncytial properties and junction potentials were studied in guinea pig vas deferens (GPVD). Treatment with 50 muM carbenoxolone reversibly and significantly increased input resistance (R (in)) (by 682.5 +/- 326.0 %, P < 0.05) and abolished cable potentials within 6-7 mins of incubation, without disturbing resting membrane potential. Carbenoxolone reversibly and significantly increased the amplitude of spontaneous excitatory junction potentials (sEJPs) by 96.9 +/- 35.45% (P < 0.05), shifted their amplitude distribution rightwards, and reduced their frequency of occurrence by 58.17 +/- 17.7% (P < 0.05), without altering their time courses. Similarly, carbenoxolone increased the amplitude of evoked excitatory junction potentials (eEJPs) by 17.7 +/- 5.88% and tau (decay) by 19.43 +/- 8.29% (P < 0.05). Our results indicate that carbenoxolone alters the electrical properties and junctional potentials of the GPVD by a mechanism consistent with a relatively specific block of gap junctions. These results suggest that gap junction mediated cell-to-cell communication may significantly modulate the electrical properties and junctional potentials of the GPVD and consequently the physiological functioning of this tissue.
Palani
D
D
Biomedical Engineering Group, School of Biosciences and Bioengineering, Indian Institute of Technology-Bombay, Mumbai, 400076, India.
Ghildyal
P
P
Manchanda
Rohit
R
D000818:Animals; D002229:Carbenoxolone / Q000494:pharmacology*; D002450:Cell Communication / Q000187:drug effects; D004594:Electrophysiology; D005071:Evoked Potentials / Q000187:drug effects; D017629:Gap Junctions / Q000187:drug effects*; D006168:Guinea Pigs; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects; D014649:Vas Deferens / Q000187:drug effects* / Q000502:physiology
D002229:Carbenoxolone