抄録
We have introduced multiple-site optical recording of transmembrane voltage activity, using a fast merocyanine-rhodanine voltage-sensitive dye (NK2761) and a multi-element (16 X 16) photodiode array, to monitor action potentials in the isolated rat atrium. The atrial wall preparation including the right or left auricle was dissected from the adult rat heart. The preparation was then stained with a voltage-sensitive dye. For suppression of optical artefacts due to contractile movements, a bathing medium containing 2,3-butanedione monoxime (BDM: 20 mM) was used. The spread of excitation was assessed optically by timing the initiation of the action potential-related extrinsic absorption changes. The pacing stimulations were applied by a bipolar electrode at 0.5 Hz. We have optically mapped the spatiotemporal patterns of the spread of excitation. When the octanol (0.1–0.2 mM) was applied to the bath, the conduction velocity of the excitation spread was reversibly decreased. The decrease in the conduction velocity was relatively nonuniform in the preparation, and spatial nonuniformity of the conduction velocity was observed. The block of the spread of excitation was sometimes observed. Furthermore, the amplitude and the rate of rise of the optical action potential also reversibly decreased. These results suggest that octanol reversibly increased the resistance of the gap junction, and decreased the electrical coupling between atrial muscle cells. [J Physiol Sci. 2008;58 Suppl:S178]
