RESUMO
2-(4'-pyridyl)-1,3-dioxolane methiodide (KCL-301-14) and 2-(1'-methyl-4' piperidyl)-1,3-dioxolane hydroiodide (KCL-301-39) facilitated the force of contraction in low doses and blocked it in higher doses in the in vivo cat soleus muscle preparation. Both drugs in the cat also reversed d-tubocurarine and succinylcholine blockade, produced post-drug repetitive activity, blocked post-tetanic potentiation (PTP), had no direct muscle affect and reversed the PTP suppression caused by d-tubocurarine and succinylcholine. In the rat phrenic nerve-diaphragm and the chick biventer cervicis preparations in vitro, facilitation, then blockade of the contraction were seen as concentrations increased. However, KCL-301-14 reversed d-tubocurarine and increased succinylcholine blockades in the rat and chick. KCl-301-39 increased both d-tubocurarine and succinylcholine blockades in the rat and chick. The different effects seen in the cat vs. the rat and chick with these drugs are probably due to species variation.