Influence of general anesthesia on acute experimental poisoning of cats with the organophosphorus pesticide Anthio

Abstract

It is shown that general anesthesia strongly influences the resistance of animals to poisoning with organophosphorus compounds (OPC) such as Anthio, weakens compensatory/adaptive responses, and possibly acts synergistically with OPC in impairing tissue respiration. One to three days after peroral administration of Anthio, reduced oxygen tension in arterial blood and increased heart and respiratory rates were recorded in cats, although the arterial blood pressure tended to drop markedly. Anthio poisoning led to profound changes in the autonomic regulation of functions, which was manifested in sharply decreased parasympathetic influences. The function of the brain's GABA-ergic system did not change appreciably. Key Words: cats; anesthesia; organophosphorus compounds; acute poisoning; Anthio pesticideWe found previously that almost all cats die 2-3 h after their acute experimental poisoning in the pentobarbital-anesthetized state with the organophosphorus pesticide Anthio given per os in a dose equal to 20% of its LDs0 value [15]. Such an effect of Anthio is not consistent with what is known about the systemic toxicity displayed by it at this dose level and raises the question of the role pentobarbital anesthesia might play in aggravating the adverse effects of acute experimental poisoning.The present study was designed to examine the impact of pentobarbital anesthesia on major parameters of respiration and systemic circulation several days after peroral administration of Anthio to alert cats in the dose indicated above. In such cats we also evaluated the effect of atropine, which is usually employed in cases of poisoning with cholinestInstitute of General Pathology and Pathological Physiology, Russian Academy of Medical Sciences, Moscow. {Presented by I. P. Ashmarin, Member of the Russian Academy of Medical Sciences) erase blockers, as well as the effect from the activation of the GABA-ergic system, which is closely associated with the cholinergic system [12]. MATERIALS AND METHODSThe experiments were conducted on 7 random-bred adult cats of both sexes weighing 2.2-2.8 kg. Under mild ether anesthesia, the animals were administered intragastrically, via a catheter, the organophosphorus pesticide Anthio (Formothion, Sandoz) in the form of an emulsion in a dose of 1/5 of the LDs0, after which the ether supply was discontinued. Several days later, the cats were anesthetized with sodium pentobarbital (40 mg/kg intraperitoneally) and prepared for examination. Details of this preparation and of the procedures used to measure parameters of respiration, systemic hemodynamics, and arterial blood are described in our previous article [15]. Five cats were injected intravenously with atropine (0.5 mg/kg) and with

Effect of the organophosphorus compound anthio on the pulmonary and systemic circulation of non-narcotized cats

“…Pulmonary vascular resistance was approximately 25% increased in comparison with the control and did not normalize on day 3. This might be due to developing arterial hypoxemia found in experiments similar to ours [6]. On the other hand, pulmo- Effect of inhalations of gaseous mixture with 7.5% O on pulmonary circulation.…”

Pathomorphological investigation of feline lungs in modeled pneumonia

“…Respiratory insufficiency probably caused by cerebral pathology [9,10] and other alterations typical of pneumonia: systemic and pulmonary circulation disorders, peripheral vascular dilatation presumably of a mosaic character, increased blood viscosity hindering microcirculation at sustained normoxia, and the development of hypercapnia associated with metabolic acidosis were observed in cats of groups I, II (Anthio against the background of Nembutal anesthesia), and IV (Anthio+turpentine).…”

“…Anthio (1/ 5 of the lethal dose) was administered to group I cats via a gastral tube under Nembutal anesthesia (30-40 mg/kg, intraperitoneally). Functional changes in the lungs, myocardium, and brain were observed during a 3-h acute experiment [8][9][10]. The animals died against the background of lowered blood pressure [8,10].…”

“…Functional changes in the lungs, myocardium, and brain were observed during a 3-h acute experiment [8][9][10]. The animals died against the background of lowered blood pressure [8,10]. In group II, Anthio was administered intragastrally under etherrausch narcosis, and then the animals were left for 72 h, after which they were examined in acute experiments.…”