تفاوتهاي ناحيه اي در مختصات شكل پتانسيل عمل گره سينوسي - دهليزي قلب خرگوش

Regional Differences in Action Potential Configuration of The Sino-Atrial Node

It is known that the mammalian sino-atrial node(SAN) is not a homogeneous tissue in terms of its structure, and function. Their main cells and zones (peripheral, transitional and central) are with regional variation in electrical activity in rabbit SAN which have been investigated by recording action potentials throughout the intact SAN (intra and extra-cellular recording), intact SAN disconnected from atrial muscle (extracelular recording), and a small ball of SAN tissue from different regions (intracellular recording). The conventional glass microelectrode was used for electrical recording and measured nine parameters. Based on the results obtained from the intact SAN and small balls APA, OS, MDP, TOP, dv/dt and rate of spontaneous activity in the central zone or balls C, D, and E, were less and the APD and CL were greater (P< 0.05) than those in the transition and peripheral zones or balls B and A respectively. Based on results from small balls of tissue and the disconnected intact SAN, the atrial muscle plays a more important role in the periphery of the SAN than in the center. This suggest that the action potential configuration of rabbit SAN is region-dependent.