Reaction of Effector Cells to Chemical Transmitters

Abstract

EARLIER work has led us to the view that the intervention of peripheral elements has a fundamental role in the regulation of nervous activity¹. This regulation, in fact, is not exclusively conditioned by the nature of the transmitter or by its mode of formation. It depends to a great extent on the more or less specific reactions of the effector cells to the substances liberated by nerve stimulation. Thus two transmitters, acetylcholine and adrenalin, act in a different way on organs like the heart and the intestines, which present different histological structures. But adrenalin causes contraction of the uterus of the pregnant cat and relaxation of the uterus of the non-pregnant cat, that is, the action of the same transmitter is dependent on the functional conditions of the reacting tissue. This suggests the possibility of local intervention of sex hormones in the peripheral regulation mechanisms of the uterus ; for it has been shown by Courrier that these hormones are capable of direct action on that organ and that the hormonal antagonism between œstrin and progesterone, for example, is directly concerned with its effector cells.