naa a22 4500 510805930 CHVBK 20180411083418.0 cr unu---uuuuu 180411e20130301xx s 000 0 eng 10.1007/s12576-012-0248-1 doi (NATIONALLICENCE)springer-10.1007/s12576-012-0248-1 The mechanism of increased postnatal heart rate and sinoatrial node pacemaker activity in mice [Elektronische Daten] [Takeshi Adachi, Shigehiro Shibata, Yosuke Okamoto, Shinichi Sato, Susumu Fujisawa, Takayoshi Ohba, Kyoichi Ono] Heart rate (HR) of mammalian species changes postnatally, i.e., HR of large animals including humans decreases, while HR in small animals such as mice and rats increases. To clarify cellular mechanisms underlying the postnatal HR changes, we performed in vivo HR measurement and electrophysiological analysis on sinoatrial node (SAN) cells in mice. The in vivo HR was ~320beats min−1 (bpm) immediately after birth, and increased with age to ~690bpm at postnatal day 14. Under blockage of autonomic nervous systems, HR remained constant until postnatal day 5 and then increased day by day. The spontaneous beating rate of SAN preparation showed a similar postnatal change. The density of the L-type Ca2+ current (LCC) was smaller in neonatal SAN cells than in adult cells, accompanied by a positive shift of voltage-dependent activation. Thus, the postnatal increase in HR is caused by both the increased sympathetic influence and the intrinsic activity of SAN cells. The different conductance and kinetics of LCC may be involved in the postnatal increase in pacemaker activity. The Physiological Society of Japan and Springer Japan, 2013 Ca2+ current nationallicence Cardiac automaticity nationallicence Development nationallicence Hyperpolarization-activated cation channel nationallicence Heart rate nationallicence Sinoatrial node nationallicence Adachi Takeshi Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, 010-8543, Akita, Japan aut Shibata Shigehiro Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, 010-8543, Akita, Japan aut Okamoto Yosuke Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, 010-8543, Akita, Japan aut Sato Shinichi Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, 010-8543, Akita, Japan aut Fujisawa Susumu Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, 010-8543, Akita, Japan aut Ohba Takayoshi Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, 010-8543, Akita, Japan aut Ono Kyoichi Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, 010-8543, Akita, Japan aut The Journal of Physiological Sciences Springer Japan 63/2(2013-03-01), 133-146 1880-6546 63:2<133 2013 63 12576 https://doi.org/10.1007/s12576-012-0248-1 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s12576-012-0248-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Adachi Takeshi Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, 010-8543, Akita, Japan aut NATIONALLICENCE 700 1- Shibata Shigehiro Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, 010-8543, Akita, Japan aut NATIONALLICENCE 700 1- Okamoto Yosuke Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, 010-8543, Akita, Japan aut NATIONALLICENCE 700 1- Sato Shinichi Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, 010-8543, Akita, Japan aut NATIONALLICENCE 700 1- Fujisawa Susumu Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, 010-8543, Akita, Japan aut NATIONALLICENCE 700 1- Ohba Takayoshi Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, 010-8543, Akita, Japan aut NATIONALLICENCE 700 1- Ono Kyoichi Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, 010-8543, Akita, Japan aut NATIONALLICENCE 773 0- The Journal of Physiological Sciences Springer Japan 63/2(2013-03-01), 133-146 1880-6546 63:2<133 2013 63 12576 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer