Previous studies have shown that vasoconstriction of blood vessels can be produced through the mechanism of conditioning.1 The present studies were carried out to determine whether these reflexes could be blocked with various medications which would interrupt the conditioned vasoconstrictive reflex but would not influence vasoconstriction from the primary stimulus. It was postulated that certain disease states, such as Raynaud's disease, could represent abnormalities of the conditioning mechanism; that is, conditioning could occur too easily or would persist for too long a time, or the magnitude of the vasoconstrictive response would be larger than normal. If these postulates were true, it would seem desirable to interrupt the conditioned vasoconstrictive response without interfering with vasoconstriction resulting from direct primary stimulation of the patient.
Methods and Materials
Twenty-seven subjects were studied, consisting of medical students, interns, residents, and nurses, none of whom had any known disease state. The studies were carried