Pharmacological actions of the venom of the Indian catfish (Plotosus canius Hamilton)

The venom of the common Indian catfish P. canius Hamilton (locally called «Kanmagur») was examined for its pharmacodynamic activity. The LD 50 of the venom in mice was found to be 3.9 mg/kg (ip). At lower doses, the venom produced a positive inotropic effect on toad and rabbit hearts, while at higher doses it produced cardiac arrest. In the isolated guineapig auricle, the venom increased the rate and amplitude of contraction. The venom increased rat blood pressure ― an action antagonised by α-adrenergic blocker (phenoxybenzamine). It reduced the rate and amplitude of rat and guineapig respiration leading to respiratory arrest and death