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New markers for type A behavior: pupil size and platelet epinephrine
R H Schneider1, S Julius, G E Moss
1Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor.
Psychosomatic Medicine
|November 1, 1987
Summary
Type A behavior is linked to higher sympathetic nervous system activity, indicated by larger pupil size and increased platelet epinephrine levels. These findings suggest a physiological basis for the Type A pattern.
Area of Science:
- Psychophysiology
- Behavioral Medicine
Background:
- The Type A behavior pattern is a potential risk factor for cardiovascular disease.
- Previous research suggests a link between Type A behavior and the sympathetic nervous system, but direct physiological markers are needed.
Purpose of the Study:
- To investigate the association between Type A behavior pattern and sympathetic nervous system activity using novel physiological markers.
- To determine if pupil size and platelet catecholamine content reflect sympathetic tone in Type A individuals.
Main Methods:
- Thirty-three healthy males were assessed for Type A behavior using the Structured Interview.
- Sympathetic tone was measured via infrared television pupillometry (pupil diameter) and platelet catecholamine content (epinephrine and norepinephrine).
- Pupillary sensitivity to alpha-adrenergic stimulation was also evaluated.
Main Results:
- Type A individuals exhibited significantly larger pupil diameters compared to Type B individuals.
- Platelet epinephrine content was elevated in Type A subjects.
- No significant differences were found in pupillary response to phenylephrine or in platelet norepinephrine levels.
Conclusions:
- Findings suggest that Type A behavior is associated with increased sympathetic nervous system tone.
- Pupil size and platelet epinephrine serve as potential indicators of autonomic nervous system activity related to behavior patterns.
- Further research is needed to fully elucidate the role of parasympathetic nervous system activity.