TY - JOUR
T1 - Conflicting effects by antibodies against connexin36 during the action of intracellular Cyclic-AMP onto electrical synapses of retinal ganglion cells
AU - Hidaka, Soh
N1 - Publisher Copyright:
© 2016 World Scientific Publishing Europe Ltd.
PY - 2016/12/1
Y1 - 2016/12/1
N2 - Alpha-type retinal ganglion cells (alpha cells) of the same class in mammalian retina are connected by gap junctions. Electrical synapses between alpha cells were examined using combined techniques of dual patch-clamp recordings, intracellular labeling and electron microscopy in the albino rat retina. In simultaneous dual whole-cell recordings from pairs of neighboring alpha cells, bidirectional electrical synapses with symmetrical junction conductance were observed in pairs with cells of the same morphological type. Regulatory domains of gap junction protein subunit connexins in electrical synapses between alpha cells by extracellular and intracellular ligands investigated by dual whole-patch clamp recordings. I examined how passage currents through electrical synapses between alpha cells are modulated by specific antibodies against connexin36 proteins, and extracellular or intracellular application of ligands. Control conditions led us to observe large passage currents between connected cells and adequate transjunctional conductance (Gj) (1.35±0.51nS). Experimental results show that high level of intracellular cyclic AMP within examined cells suppress electrical synapses between the neighboring cells. Gj between examined cells reduced to 0.15±0.04nS. Under application of dopamine (1.25±0.06nS) or intracellular cyclic GMP (0.98±0.23nS), however, Gj also remains as in the control level. Intracellular application of an antibody against the cytoplasmic loop of connexin36 reduced Gj (0.98±0.23nS). Cocktail of the antibody against cytoplasmic connexin36 and intracellular cyclic AMP leaves Gj as in the level by single involvement of the cytoplasmic antibody. The elimination of Gj by the cytoplasmic antibody was in a dose-dependent manner. These results suggest that binding domains against cyclic AMP may be present in the cytoplasmic sites of connexin proteins to regulate channel opening of gap junctions between mammalian retinal alpha ganglion cells.
AB - Alpha-type retinal ganglion cells (alpha cells) of the same class in mammalian retina are connected by gap junctions. Electrical synapses between alpha cells were examined using combined techniques of dual patch-clamp recordings, intracellular labeling and electron microscopy in the albino rat retina. In simultaneous dual whole-cell recordings from pairs of neighboring alpha cells, bidirectional electrical synapses with symmetrical junction conductance were observed in pairs with cells of the same morphological type. Regulatory domains of gap junction protein subunit connexins in electrical synapses between alpha cells by extracellular and intracellular ligands investigated by dual whole-patch clamp recordings. I examined how passage currents through electrical synapses between alpha cells are modulated by specific antibodies against connexin36 proteins, and extracellular or intracellular application of ligands. Control conditions led us to observe large passage currents between connected cells and adequate transjunctional conductance (Gj) (1.35±0.51nS). Experimental results show that high level of intracellular cyclic AMP within examined cells suppress electrical synapses between the neighboring cells. Gj between examined cells reduced to 0.15±0.04nS. Under application of dopamine (1.25±0.06nS) or intracellular cyclic GMP (0.98±0.23nS), however, Gj also remains as in the control level. Intracellular application of an antibody against the cytoplasmic loop of connexin36 reduced Gj (0.98±0.23nS). Cocktail of the antibody against cytoplasmic connexin36 and intracellular cyclic AMP leaves Gj as in the level by single involvement of the cytoplasmic antibody. The elimination of Gj by the cytoplasmic antibody was in a dose-dependent manner. These results suggest that binding domains against cyclic AMP may be present in the cytoplasmic sites of connexin proteins to regulate channel opening of gap junctions between mammalian retinal alpha ganglion cells.
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U2 - 10.1142/S021963521650031X
DO - 10.1142/S021963521650031X
M3 - Article
C2 - 28052704
AN - SCOPUS:85008316403
SN - 0219-6352
VL - 15
SP - 571
EP - 591
JO - Journal of integrative neuroscience
JF - Journal of integrative neuroscience
IS - 4
ER -