TY - JOUR
T1 - Suppression of electrical synapses between retinal amacrine cells of goldfish by intracellular cyclic-AMP
AU - Hidaka, Soh
N1 - Funding Information:
This work was performed in the 21st-Century COE Program to Fujita Health University (Directors: Drs. Yoshizo Asano and Yoshikazu Kurosawa) from the Japanese Ministry of Education, Culture, Sports, Science and Technology. Our studies were in part supported by the Science Research Promotion Fund from the Promotion and Mutual Aid Corporation for Private Schools of Japan (No. 231016 ), and by Grants-in-Aid for Scientific Research from the Japanese Ministry of Education, Culture, Sports, Science and Technology to S.H. (No. 03857020 , 04857016 and 10680754 ). I am grateful to Dr. Roman R. Poznanski for reading the first draft of this manuscript, and providing helpful suggestions for improvement. My high-voltage electron microscopical studies were performed in the co-operative program of National Institute for Physiological Sciences (Okazaki) with numbers of 2008-HVEM06, 2009-HVEM502, 2010-HVEM516 and 2011-HVEM506. I greatly appreciate Drs. Kazuyoshi Murata, Tatsuo Arii, Noboru Yamaguchi and Katsumi Kato for excellent maintenance of the HITACHI H-1250M electron microscope and valuable advice pertaining to ultrastructural studies. I thank Drs. Gen Niini, Toshiaki Kato, Yang Lu and Yoko Hashimoto for technical advice pertaining to ultrastructural and histochemical experiments, and Chieko Nishikawa, Masayo Kamiya, Michiyo Maehara, Keiichi Iizuka, Daisuke Ishihara, Junko Ikoma and Mayu Watanabe for technical assistance.
PY - 2012/4/17
Y1 - 2012/4/17
N2 - Retinal amacrine cells of the same class in cyprinid fish are homotypically connected by gap junctions. The permeability of their gap junctions examined by the diffusion of Neurobiotin into neighboring amacrine cells under application of dopamine or cyclic nucleotides to elucidate whether electrical synapses between the cells are regulated by internal messengers. Neurobiotin injected intracellularly into amacrine cells in isolated retinas of goldfish, and passage currents through the electrical synapses investigated by dual whole-patch clamp recordings under similar application of their ligands. Control conditions led us to observe large passage currents between connected cells and adequate transjunctional conductance between the cells (2.02 ± 0.82 nS). Experimental results show that high level of intracellular cyclic AMP within examined cells block transfer of Neurobiotin and suppress electrical synapses between the neighboring cells. Transjunctional conductance between examined cells reduced to 0.23 nS. However, dopamine, 8-bromo-cyclic AMP or high elevation of intracellular cyclic GMP leaves gap junction channels of the cells permeable to Neurobiotin as in the control level. Under application of dopamine (1.25 ± 0.06 nS), 8-bromo-cyclic AMP (1.79 ± 0.51 nS) or intracellular cyclic GMP (0.98 ± 0.23 nS), the transjunctional conductance also remains as in the control level. These results demonstrate that channel opening of gap junctions between cyprinid retinal amacrine cells is regulated by high level of intracellular cyclic AMP.
AB - Retinal amacrine cells of the same class in cyprinid fish are homotypically connected by gap junctions. The permeability of their gap junctions examined by the diffusion of Neurobiotin into neighboring amacrine cells under application of dopamine or cyclic nucleotides to elucidate whether electrical synapses between the cells are regulated by internal messengers. Neurobiotin injected intracellularly into amacrine cells in isolated retinas of goldfish, and passage currents through the electrical synapses investigated by dual whole-patch clamp recordings under similar application of their ligands. Control conditions led us to observe large passage currents between connected cells and adequate transjunctional conductance between the cells (2.02 ± 0.82 nS). Experimental results show that high level of intracellular cyclic AMP within examined cells block transfer of Neurobiotin and suppress electrical synapses between the neighboring cells. Transjunctional conductance between examined cells reduced to 0.23 nS. However, dopamine, 8-bromo-cyclic AMP or high elevation of intracellular cyclic GMP leaves gap junction channels of the cells permeable to Neurobiotin as in the control level. Under application of dopamine (1.25 ± 0.06 nS), 8-bromo-cyclic AMP (1.79 ± 0.51 nS) or intracellular cyclic GMP (0.98 ± 0.23 nS), the transjunctional conductance also remains as in the control level. These results demonstrate that channel opening of gap junctions between cyprinid retinal amacrine cells is regulated by high level of intracellular cyclic AMP.
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U2 - 10.1016/j.brainres.2012.01.054
DO - 10.1016/j.brainres.2012.01.054
M3 - Article
C2 - 22425185
AN - SCOPUS:84859421872
VL - 1449
SP - 1
EP - 14
JO - Molecular Brain Research
JF - Molecular Brain Research
SN - 0006-8993
ER -