Abstract
Cardiac physiology of fish models is an emerging field given the ease of genome editing and the development of transgenic models. Several studies have described the cardiac properties of zebrafish (Denio rerio). The goldfish (Carassius auratus) belongs to the same family as the zebrafish and has emerged as an alternative model with which to study cardiac function. Here, we propose to acutely study electrophysiological and systolic Ca2+ signaling in intact goldfish hearts. We assessed the Ca2+ dynamics and the electrophysiological cardiac function of goldfish, zebrafish, and mice models, using pulsed local field fluorescence microscopy, intracellular microelectrodes, and flash photolysis in perfused hearts. We observed goldfish ventricular action potentials (APs) and Ca2+ transients to be significantly longer when compared to the zebrafish. The action potential half duration at 50% (APD50) of goldfish was 370.38 ± 8.8 ms long, and in the zebrafish they were observed to be only 83.9 ± 9.4 ms. Additionally, the half duration of the Ca2+ transients was also longer for goldfish (402.1 ± 4.4 ms) compared to the zebrafish (99.1 ± 2.7 ms). Also, blocking of the L-type Ca2+ channels with nifedipine revealed this current has a major role in defining the amplitude and the duration of goldfish Ca2+ transients. Interestingly, nifedipine flash photolysis experiments in the intact heart identified whether or not the decrease in the amplitude of Ca2+ transients was due to shorter APs. Moreover, an increase in temperature and heart rate had a strong shortening effect on the AP and Ca2+ transients of goldfish hearts. Furthermore, ryanodine (Ry) and thapsigargin (Tg) significantly reduced the amplitude of the Ca2+ transients, induced a prolongation in the APs, and altogether exhibited the degree to which the Ca2+ release from the sarcoplasmic reticulum contributed to the Ca2+ transients. We conclude that the electrophysiological properties and Ca2+ signaling in intact goldfish hearts strongly resembles the endocardial layer of larger mammals.
Highlights
In the last 10 years, fish hearts have become a very popular model for studying heart function (Nemtsas et al, 2010; Huttner et al, 2013; Ravens, 2018; van Opbergen et al, 2018b; Zhang et al, 2018)
We find that goldfish hearts have a similar action potentials (APs) temperature (Gurabi et al, 2014) and heart rate dependency (Krishnan and Antzelevitch, 1991; Burashnikov and Antzelevitch, 1998) when compared to larger mammals
The zebrafish heart needs to be cannulated using a 32- to 34-gauge needle, and the goldfish heart can be cannulated on a 27-gauge needle
Summary
In the last 10 years, fish hearts have become a very popular model for studying heart function (Nemtsas et al, 2010; Huttner et al, 2013; Ravens, 2018; van Opbergen et al, 2018b; Zhang et al, 2018). In developmental studies (Novak et al, 2006; Chi et al, 2010; Chablais and Jazwinska, 2012; Ramachandran et al, 2013; Ding et al, 2017), the zebrafish (Danio rerio) has been the model of choice for the possibility of performing transgenesis (Chopra et al, 2010; Huttner et al, 2013; Konantz and Antos, 2014; Serbanovic-Canic et al, 2017), and for studying cardiac physiology of larger mammals, including humans (Nemtsas et al, 2010; Ravens, 2018; van Opbergen et al, 2018b). It is possible to cannulate the bulbus arteriosus of the zebrafish heart, it is difficult to effectively change the perfusate quickly enough to perform pharmacological experiments. This is due to the low perfusion rate the zebrafish heart needs to maintain good hemodynamic and mechanical conditions. The ventricular wall of the zebrafish heart is not thick enough (Hu et al, 2001) to consistently perform flash photolysis experiments at an intact heart level without undergoing considerable damage
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
