Effects of aconitine on [Ca2+] oscillation in cultured myocytes of neonatal rats.
In order to investigate the effects of aconitine on [Ca2+] oscillation patterns in cultured myocytes of neonatal rats, fluorescent Ca2+ indicator Fluo-4 NW and laser scanning confocal microscope (LSCM) were used to detect the real-time changes of [Ca2+] oscillation patterns in the cultured myocytes before and after aconitine (1.0 micromol/L) incubation or antiarrhythmic peptide (AAP) and aconitine co-incubation. The results showed under control conditions, [Ca2+] oscillations were irregular but relatively stable, occasionally accompanied by small calcium sparks. After incubation of the cultures with aconitine, high frequency [Ca2+] oscillations emerged in both nuclear and cytoplasmic regions, whereas typical calcium sparks disappeared and the average [Ca2+] in the cytoplasm of the cardiomyocyte did not change significantly. In AAP-treated cultures, intracellular [Ca2+] oscillation also changed, with periodic frequency, increased amplitudes and prolonged duration of calcium sparks. These patterns were not altered significantly by subsequent aconitine incubation. The basal value of [Ca2+] in nuclear region was higher than that in the cytoplasmic region. In the presence or absence of drugs, the [Ca2+] oscillated synchronously in both the nuclear and cytoplasmic regions of the same cardiomyocyte. It was concluded that although oscillating strenuously at high frequency, the average [Ca2+] in the cytoplasm of cardiomyocyte did not change significantly after aconitine incubation, compared to the controls. The observations indicate that aconitine induces the changes in [Ca2+] oscillation frequency other than the Ca2+ overload.
Liu
Yan
Y
Department of Forensic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China. liuyan@mails.tjmu.edu.cn
Zhang
Shiwei
S
Liang
Man
M
Liu
Qian
Q
Liu
Liang
L
D000157:Aconitine / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D020013:Calcium Signaling / Q000187:drug effects*; D002478:Cells, Cultured; D005260:Female; D008297:Male; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000157:Aconitine