Electric response in the mammary gland

¹ Biological Laboratories, Harvard University, Cambridge, Massachusetts

Our previous investigations have indicated that ‘let-down’ sensation in the mammary gland in nursing, or on injection of Pituitrin, is accompanied by slow electric response. This was believed to emanate from secreting-gland cells or from contractile myoepithelial cells. Indirect control indicated that sweat-gland activity, related to emotional reaction, played little part in electric response recorded from the breast. We have controlled this question of sweat-gland participation in observed response by recording simultaneously from the palm of the hand and from the areola in a non-lactating subject. It was found that spoken words evoking emotional reactions were accompanied by large electric responses from the palm, but from the areola there were either no responses or very small inverse deflections, presumably due to sweat glands in the skin of the thorax. Observations on lactating subjects showed that during nursing occasional deflections in the palmar record resembled those evoked in word tests, but in no case did the palmar record show a slow response synchronized with that recorded from the areola during the letdown. From these observations we conclude that sweat-gland reactions play little part in the characteristic let-down electric response led off from the areola. This must arise from a different source, presumably either the myoepithelial cells, the secreting cells, or both.