The Electrophysiological Effects Of The Venom From Chinese Spider Chilobrachys Jingzhao On Neonatal Rat Cardiac Ventricular Myocytes

Heart disease is one of the top 3 killer diseases, threatening human health. A large number of studies have demonstrated dysfunction and heart failure closely related to cardiac ion channels which affect the shape and duration of the cardiac action pote ntial as well as the potential of resting membrane. The venom of the Chinese spider Chilobrachys jingzhao contains a great quantity of pep tide toxins targeting various ion channels, suggesting an attractive strategy for prevention and treatment of various diseases.However, rarely studies revealed the effects of spider toxins on cardiac ion channels. In this study, whole cell patch clamp technique was applied to record action potential duration(APD), sodium current(INa), rapidly activating and inactivating transient outward currents(Ito1), L-type calcium current( I Ca L), slow delayed rectifier current(I Ks), and HERG current( I Kr) and the inward rectifier current(I K1) on neonatal rat ventricular myocytes(NRVMs). To our surprise, the results showed that 100 μg/mL jingzhao venom can largely increase I CaL by 132 ± 4.0%, while INa were decreased by 96.7 ± 3.4% and IKr were inhibited by 54.3 ± 3.2% peak currents and 35.3 ± 5.3% the end of depolarizing steps and 60.8 ± 4.3% the tail currents. Yet, I Ks, Ito11 and I K1 currents were not affected obviously by the venom, suggesting that the venom represented a multifaceted pharmacological profile. Moreover, the venom prolongs APD weakly and in a frequency-de pendent manner in NRVMs. Taken togezher, our data eluc idate the effects of Chilobrachys jingzhao venom on cardiac ions channels and implicate its potential in cardiac dysfunctions therapy.