[Effect of pharmacological substances on nociceptive vasomotor reflexes in experiments on unanesthetized animals]

Experiments on unanesthetized cats (conscious and curarized) were made to analyze the method of studying the effect of pharmacological substances on the pressor vasomotor reflexes produced by nociceptive stimulation. It was shown that the activity profiles of the drugs depend not only on their cardiovascular properties but also on the parameters of stimulation applied to the reflex recording, which is related to the shape of the curve of reflex magnitude dependence on the stimulation intensity. The most precise test in the application of the method to the unanesthetized animals involved the recording of the threshold of reflex occurrence, with the use of curare-like drugs being mandatory. Making of experiments without use of the curare-like agents or without considering the shape of the curve of reflex magnitude dependence on the parameters of stimulation might lead to errors in the appraisal of the results obtained.