ADRENALECTOMY IN RATS AND ITS INFLUENCE ON LOCAL ANESTHESIA OF PERIPHERAL NERVES

¹ Department of Pharmacology, New Jersey College of Medicine, Jersey City, New Jersey

The block of impulse conduction by cocaine was examined in peripheral nerves removed from adrenalectomized rats experiencing a hyponatremic state. The results show that these nerves are more sensitive to the action of the drug than are nerves from normal rats. From the relationship of the intensity of the local anesthetic effects to the in vivo extracehlular sodium and potassium levels and from other experimental facts, it is concluded that the enhanced pharmacologic action is correlated specifically with reduced sodium levels. The outcome of these experiments was predicted by the hypothesis that local anesthetics block nerve conduction because they are competitive antagonists of the sodium ion. Since the enhanced action of the anesthetic is related to sodium deficiency itself and not directly to a loss of adrenal function, it may be expected that a similar potentiation of local anesthetics would be observed in other experimental and clinical situations in which sodium deficiency exists.