Regulation of calcium oscillations by IP<inf>3</inf>R and RyR in neonatal rat cardiomyocytes

Ying QI; Xinyi Zhao; Jiahui Yao; Wenjun Xie; Yi Zhang

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Regulation of calcium oscillations by IP3R and RyR in neonatal rat cardiomyocytes

VernacularTitle:IP3R与RyR对新生大鼠心肌细胞钙振荡调控的研究
Author: Ying QI ^{1
,

2} ; Xinyi ZHAO ¹ ; Jiahui YAO ¹ ; Wenjun XIE ³ ; Yi ZHANG ¹
Author Information

1. Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an 710061
2. School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
3. School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
Publication Type:Journal Article
Keywords: 1,4,5-trisphosphate receptor (IP3Rs); ryanodine receptor (RyR); neonatal rat; cardiomyocyte; calcium oscillation
From: Journal of Xi'an Jiaotong University(Medical Sciences) 2022;43(6):801-806
CountryChina
Language:Chinese
Abstract: 【Objective】 To explore the roles of 1,4,5-trisphosphate receptor (IP3Rs) and ryanodine receptors (RyRs), the two main Ca²⁺ release channels in sarcoplasmic reticulum (SR), in the regulation of intracellular Ca²⁺ oscillations in neonatal rat cardiomyocytes (NRCMs). 【Methods】 We isolated and cultured NRCMs for different days, then loaded them with Ca²⁺ indicator fura-2 and performed real-time fluorescent imaging. To distinguish the effects of IP3Rs and RyRs, NRCMs were pre-treated with phenylephrine (PE, IP3Rs agonist), caffeine (RyRs agonist), 2-APB (IP3Rs antagonist), and tetracaine (RyRs antagonists), respectively. 【Results】 The cultured monolayer NRCMs showed spontaneous synchronized Ca²⁺ oscillations. PE activation or 2-APB blockade of IP3Rs increased or reduced the frequency of Ca²⁺ oscillations in NRCMs, accordingly, with no significant effect on the amplitude of Ca²⁺ oscillations. Activation of RyRs with caffeine increased the frequency of Ca²⁺ oscillations, but unsynchronized the intercellular rhythm of calcium release and beating pace, while blocking RyRs with tetracaine completely abolished the Ca²⁺ oscillations and beats in NRCMs. In addition, the effect of PE stimulation on Ca²⁺ oscillation frequency gradually decreased along with cultured days. 【Conclusion】 IP3Rs regulate the rhythm of calcium oscillations, whereas RyRs are the main channel for bulky store Ca²⁺ release.