Alopecosa nagpag acts on cardiac ventricular myocytes to kill prey

Abstract

Spiders are excellent predator to kill their prey by peptide toxins from its venoms. Alopecosa nagpag (A. nagpag) is a new identified wolf spider distributing in Yunnan province and nothing has known about the venom. In this study, venom of A. nagpag showed mild toxicity to Kunming mouse with LD50 of 3.32 mg/kg. Action potential duration (APD) was prolonged in a frequency-dependent manner and whole currents of neonatal rat ventricular myocytes (NRVMs) were inhibited by venom. Meanwhile, venom of A. nagpag could largely increase L calcium currents (ICaL). Whereas sodium current (INa) and rapidly activating delayed rectifier potassium current (IKr) were significantly decreased by 100 g/mL venoms. No obvious inhibition was found on other ion channels such as rapidly activating and inactivating transient inward (IK1), rapid (IKr) and slow (IKs). As those ion channels play critical role in rhythm of cardiac ventricular myocytes, A. nagpag may lead prey to death by changing cardiac rhythm.