NEW ADRENOLYTICUM AND REVERSAL EPINEPHRINE REACTION

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1. With Sanborn's electromanometer the systolic, the diastolic and the dynamical mean pressure are estimated in dogs, injecting epinephrine intravenously under the isomytal anesthesia. The changes of the action mode of epinephrine by premedication of CCK-179, DHK and Chlorpromazine etc. are observed with respect to respiration, cardiac rates and especially arterial pressure.2. We have differentiate the blood pressure response with inravenous application of epinephrine and neo-synephrine into three phases. The 1st phase appears within 15″ after the injection and is characterized with the elevation of blood pressure accompanying with tachycardia. The 2nd phase appears 25″-40″ thereafter, and is characterized with temporarily the mild elevation or the slight depression, in addition to bradycardia, not seldom complicated with arrhythmia. The 3rd phase is observed within 60″ after the injection and is characterized with the maximal rise of blood pressure which returns to the initial level within 2′-3′ accompanying with tachycardia.In the 1st phase the chief causal rôle is assumed to be the cardiotonic reflex, in the 2nd phase to be the pressoreceptoric nerve reflex and in the 3rd phase to be peripheral vascular action. In the 1st and the 3rd phase the elevation of diastolic pressure is more remarkable than that of systolic pressure.3. The reversal epinephrine reaction can be induced with the use of the properly selected dosage of adrenolyticum. At that juncture the elevation of B.P. in the 1st phase cannot be suppressed, but bradycardia or arrhythmia in the 2nd phase is able to be ameliorated, while the tachycardia in the 1st and 3rd phase remaines unchanged. The epinephrine-apnea can be inhibited by application of adrenolyticum. The elevation of blood pressure brought on with neo-synephrine is suppressed by the application of adrenolyticum, but there cannot be observed the reversal reaction.4. The main causes of the reversal epinephrine response, that is to say, the depression owing to injection of epinephrine consist in the inhibition of the vascular contraction on the one side, and the preservation of the inhibitory vascular dilatation on the another side. This vascular dilatation depends more dominantly upon the direct vasodilatation in peripheral vascular area brought on with the epinephrine than upon the pressorece-ptoric carotid sinus reflex which is influenced with epinephrine. Thus the essential cause of epinephrine response is assumed to be a change of the state in peripheral nerve endings.5. Epinephrine tachycardia is due to the suppression of the vagal tonus; this is one of the inhibitory response of the epinephrine and cannot be blocked with adrenolyticum.6. It is mainly owing to the disloading of the heart induced by the inhibition of the elevation of blood pressure that the epinephrine arrhythmia can be ameliorated with the use of adrenolyticum.7. The reversal epinephrine response can be found with adequate application of Regitine, Yohimbine and Priscol, while the premedication of CCK-179, DHK and Chlorpromazine disclose no decided reversal reaction. The latter three drugs effect not only peripherally but also, to certain extent, centrally.