EFFECT OF TASTE &TRIGEMINAL STIMULATION ON NEUROENDOCRINE VALUES

Duke University, Durham NC

Investigators

Linked publications & trials

Abstract

Little is currently known about acute or long-term physiological impacts of chronic exposure to unpleasant tastes and oral irritation from medications. Unpleasant tastes have been found to lower compliance with drug regimens but it is not yet known if reduced compliance is due simply to the aversive aspects of the taste or to physiological side-effects caused by the sensation. This exploratory study is being performed to determine if a single brief exposure to bitter taste and/or oral irritation has a physiological effect on neuroendocrine levels (specifically norepinephrine, epinephrine, and cortisol) in humans. Norepinephrine, epinephrine, and cortisol were investigated because they are associated with stress and arousal. Secretion of norepinephrine and epinephrine involves the adrenal-medullary catecholamine system while the release of cortisol involves the pituitary-adrenal cortical system. Subjects participate individually in one 4 1/2 hour session on the General Clinical Research Center at Duke University Medical School. Four oral stimuli are tested: water (control), carbonated water, Invirase (a bitter drug used to treat HIV infection), and capsaicin (component in chili pepper). Invirase (0.09 mM) and capsaicin (100 ppm) had strong perceived intensities but were not be harmful to the subjects. The taste stimuli are presented in a fixed order: water, carbonated water, bitter water (Invirase), and capsaicin. A saline lock is placed in a peripheral arm vein sixty minutes prior beginning the study. Then a baseline blood draw is performed followed by delivery of 10 ml of the first oral stimulus (water) squirted into the mouth. Subjects swish the sample throughout the oral cavity and then expectorate. Additional blood samples are taken at 5 minutes, 10 minutes, and 25 minutes after stimulus administration. There is a twenty-five minute break between each test stimulus. Three test stimuli are then tested in a manner similar to the control stimulus (water), i.e. blood draws were taken immediately before, and 5, 10, and 25 minutes after administration of the stimulus. The subjects' pulse and blood pressure is taken immediately before stimulus administration, and 25 minutes after stimulus administration. Subjects also rate the perceived overall intensity and pleasantness of each stimulus. An analysis of variance is performed to determine is there are differences between stimuli in their effects on neuroendocrine levels.