The histochemical method of Axelsson coupled with photometry was used to study variations in the content of biogenic amines in different rat organs (myocardium, vas deferens, mesenteric vessels, iris, atrial and ventricular heart valve) under the effect of odiphalin and difril. The results obtained indicate that the organs with direct, indirect and mixed innervation differ in the pattern of response to the pharmacological agents administered. Venous vessels proved to be the most sensitive to the action of odiphalin and difril. The data obtained warrant a conclusion about the heterogeneity of adrenergic nerves in organs and tissues.