Effects of Vochysia haenkeana extract on the neuromuscular blockade induced by Bothrops jararaca venom on chick biventer cervicis preparation in vitro

Abstract

Vochysia haenkeana extract (Vh-E) was assessed against the neuromuscular blockade induced by Bothrops jararaca venom on chick biventer cervicis (BC) preparation. Pre- and post-venom incubation treatments (Pre-vit and Post-vit) were analysed here. Contractures ACh (110 µM) and KCl (20 mM) were evoked before and after addition of venom without stimulation. Vh-E (600 µg/mL) under Pre-vit was more efficient to neutralize the neuromuscular blockade by venom (40 µg/mL) [72.5±4.6% (venom) vs. 45.2±14% (Vh-E) of blockade, p<0.05, n=4]. Vh-E (600 µg/mL) did not cause significant changes under Post-vit [72.5±4.6% (venom) vs. 63.4±8.2% (Vh-E) of blockade, n=4]. The Pre-vit inhibited the blockade of the contracture to ACh (106±17% of response; n=4) while the Post-vit was able to attenuate the effect of the venom on this contracture (55±5% of response; n=4); related to those contractures to KCl both of treatments with Vh-E attenuated the blocker effect of the venom (62.5±7.7% and 55±5% of response for Pre-vit and Post-vit, respectively; n=4). In conclusion, Vh-E neutralizes partially the neuromuscular blockade in Pre-vit, an effect that can be related to preserved function of “extrinsic” post-synaptic receptors, by measured contractures in response to ACh. The myotoxicity of the venom was significantly reduced by Vh-E in both, Pre-vit and Post-vit, by measured contractures in response to KCl.