THE EFFECT OF MERCUROUS CHLORIDE (CALOMEL) AND EPINEPHRINE (SYMPATHETIC STIMULATION) ON RATS

Abstract

It has been found that calomel will produce retardation of growth and loss of sodium and chloride from tissue with or without associated functional renal insufficiency. The findings are compared with data obtained by injecting a mercurial diuretic, Mercuhydrin®, into rats. In young rats given 10 mg of calomel, no renal structural change is seen 1 to 4 days after ingestion but the concentration of urea nitrogen in the blood is slightly elevated. If one injection of epinephrine (0.5 mg) is given to the young rat treated with calomel, hemoconcentration, hypertension, 16% loss of total content of chloride from the body and reduction in volume of the chloride space, increased insensible water loss, moderate rise in concentration of urea nitrogen in the blood and a renal lesion in the outer area of the renal medulla (upper portion of Henle's loop) are all found within 24 hours. The animals developed a weak, scrawny appearance, and in some instances distinct coldness to palpation and blueness of the extremities. Epinephrine, when injected into normal rats, produced a lesser increase in insensible loss of water and only 6% loss of content of chloride from the body. Hypertension was not sustained. The changes demonstrated in the current experiments with rats resemble many of the findings in acrodynia. In acrodynia, sweating, hypertension, tachycardia, vasospasm, increased insensible loss of water, raised venous pressure, and increased excretion of steroids all support the concept of sympathetic preponderance. Increased adrenal cortical function also exists but to a lesser extent. Hence, acrodynia must represent "failure of adaptation" or failure to withstand stress. It is suggested that mercury potentiates directly or indirectly the action of epinephrine in the body and that the coexistence of sympathetic stress plus calomel can give rise to acrodynia. Loss of extracellular volume resulting from mercurial diuretic effects, and from loss of water from the skin potentiates sympathetic and adrenal activity. Adrenal hormones are ineffective in conserving sodium chloride at the renal level in the presence of mercury. Augmented sympathetic activity leads to renal anoxia, vasospasm, and renal pressor effects. Renal damage may result and augment the vasospasm and hypertension.