[Effect of cholinesterase (ChE) reactivators on hemodynamics in animals. II. Reactions of the circulatory and respiratory systems of dogs after administration of ChE reactivators].

Different actions of pralidoxim and obidoxim were shown in studies on the influence of ChE reactivators (administered in doses of 10, 20, 40 mg/kg) on the circulatory and respiratory system. Blood flow velocity, arterial blood pressure in the carotid artery, the frequency and amplitude of breathing were recorded continuosly 60 min before and after intravenous injection of the reactivator. From these data the pulse rate, blood flow rate and the coefficient of the peripheral vascular resistance were calculated. At the same time pulse pressure was determined. Pralidoxim (PAM) acts parasympathicolitically on the heart-vascular system. It causes blood vessel shrinkage and decreases blood flow which is accounted for by increased vascular resistance by 20-40%. Such reactions cause, particularly after lower doses, increased arterial pressure and pulse rate by 15%. A 10 mg/kg dose of obidoxim increased pulse rate and blood flow for 15 min after the injection after 15 min the blood flow gradually decreased with simultaneous increase of the vascular resistance by 30%, as compared with the initial values. At larger doses it evoked mainly vascular reactions characterized by a constant increase of blood flow with simultaneous decrease of the vascular area. The ChE reactivators used stimulated the function of the respiratory system, which becomes apparent by increasing frequency of breathing with simultaneous increase of its amplitude. In these studies no differences were found in the action of obidoxim: Toxogonin (E. Merck) and Toxobidin (Polfa).