Methoxy-catecholamine excretion and the mecholyl test.

THE response of systolic blood pressure to the subcutaneous injection of mecholyl has been studied repeatedly as a correlate of psychopathological state since the initial report of MYERSON.~ In 1948, FUNKENSTEIN et ~1.~ standardized a test using the response of systolic blood pressure to epinephrine and to mecholyl, and correlated these response patterns with the outcome following electroconvulsive treatment. ROSE,~ FEINBERG~ and GELLHORN~ have written comprehensive reviews of various studies and problems in the measurement and interpretation of the mecholyl test. BLUMBERG~ reported on the reproducibility of the test and defined the limits of variance of a single measurement derived from the mecholyl response, i.e. the mecholyl area. This mecholyl area, being an algebraic sum of both hypotensive and hypertensive portions of the response, was found to be more reproducible than any scoring based on the shape of the actual curve. The response of the systolic blood pressure to an injection of mecholyl is the resultant of an interconnected series of events, beginning with the reaction of the target organ to mecholyl with dilation of blood vessels. The degree of alteration of blood pressure level may be determined by the elastic dynamics of the vessels, the sensitivity of the circulatory baroceptors and the state of responsivity of the central autonomic regulatory mechanisms and of the effector neurons to central stimulation. The efferent compensatory response may involve the release of sympathetic amines, such as E and NE, into the circulation. The modal level of continuous activity of the sympathetic nervous system may be defined as sympathetic tone. Sympathetic reactivity may be defined as the compensatory response of the sympathetic nervous system to alterations in resting states, and may entail changes in outflow from the diencephalon and secondarily increased release of pressor amines. However, mecholyl response need not be governed by autonomic nervous system factors alone. The elasticity of blood vessels diminishes with age and the compensatory vasoconstrictor response of the blood vessels to central stimulation may be weaker and