caa a22 4500 477120067 CHVBK 20180405111634.0 cr unu---uuuuu 170330e19960401xx s 000 0 eng 10.1007/BF00227885 doi (NATIONALLICENCE)springer-10.1007/BF00227885 Regulation of cardiac gap junction channel permeability and conductance by several phosphorylating conditions [Elektronische Daten] [Brenda Kwak, Habo Jongsma] Short term (15 min) effects of activators of protein kinase A (PKA), PKC and PKG on cardiac macroscopic (gj) and single channel (γj) gap junctional conductances were studied in pairs of neonatal rat cardiomyocytes. Under dual whole-cell voltage-clamp, PKC activation by 100 nM TPA increased gj by 16 ± 2% (mean ± S.E.M, n=9), 1.5 mM of the PKG activator 8-bromo-cGMP (8Br-cGMP) decreased gj by 26 ± 2% (n=4), whereas 1.5 mM of the PKA activator 8Br-cAMP did not affect gj (1 ± 5%, n=11). Single cardiac gap junction channel events, resolved in the presence of heptanol, indicated two γj sizes of 20 pS and 40-45 pS. Under control conditions, the larger events were most frequently observed. Whereas 8Br-cAMP did not change this distribution, TPA or 8Br-cGMP shifted the γj distribution to the lower sizes. Diffusion of 6-carboxyfluorescein (6-CF), a gap junction permeant tracer, from the injected cell to neighboring cells was studied on small clusters of neonatal rat cardiomyocytes. Under control conditions, 6-CF labeled 8.4 ± 0.4 cells (mean ± S.E.M, n=31). Whereas 8Br-cAMP did not change the extent of dye transfer (8.1 ± 0.5 cells, n=10), TPA restricted the diffusion of 6-CF to 2.2 ± 0.2 cells (n=30) and 8Br-cGMP to 3.5 ± 0.3 cells (n=10). This suggests that permeability and single channel conductance of Cx43 gap junction channels are parallel related. Altogether, these results point to the differential modulation of electrical and metabolic coupling of cardiac cells by various phosphorylating conditions. Kluwer Academic Publishers, 1996 connexin43 nationallicence protein kinases nationallicence macroscopic junctional conductance nationallicence single channel conductance nationallicence dye coupling nationallicence Kwak Brenda Department of Medical Physiology and Sports Medicine, Utrecht University, PO Box 80043, 3508, TA Utrecht, The Netherlands aut Jongsma Habo Department of Medical Physiology and Sports Medicine, Utrecht University, PO Box 80043, 3508, TA Utrecht, The Netherlands aut Molecular and Cellular Biochemistry Kluwer Academic Publishers 157/1-2(1996-04-01), 93-99 0300-8177 157:1-2<93 1996 157 11010 https://doi.org/10.1007/BF00227885 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00227885 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kwak Brenda Department of Medical Physiology and Sports Medicine, Utrecht University, PO Box 80043, 3508, TA Utrecht, The Netherlands aut NATIONALLICENCE 700 1- Jongsma Habo Department of Medical Physiology and Sports Medicine, Utrecht University, PO Box 80043, 3508, TA Utrecht, The Netherlands aut NATIONALLICENCE 773 0- Molecular and Cellular Biochemistry Kluwer Academic Publishers 157/1-2(1996-04-01), 93-99 0300-8177 157:1-2<93 1996 157 11010 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer