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Measurement of Smooth Muscle Function in the Isolated Tissue Bath-applications to Pharmacology Research
Published on: January 19, 2015
Comparison of TWA and PEP as indices of α2- and ß-adrenergic activation
1Institute of Psychobiology, Department of Clinical Psychophysiology, University of Trier, Johanniterufer 15, 54290, Trier, Germany. s1lidros@uni-trier.de.
Rationale:
Pre-ejection period (PEP) and T-wave amplitude (TWA) have been used to assess sympathetic nervous system (SNS) activity. Here we report two single-blinded, placebo-controlled intravenous (IV) drug application studies in which we pharmacologically modified SNS activity with epinephrine (study 1) as well as dexmedetomidine (alpha2-agonist) and yohimbine (alpha2-antagonist) (study 2). Restricted heart rate (HR) intervals were analyzed to avoid confounding effects of HR changes.
Objective:
Study 1 served to replicate previous findings and to validate our approach, whereas study 2 aimed to investigate how modulation of central SNS activity affects PEP and TWA.
Methods:
Forty healthy volunteers (58% females) participated in study 1 (between-subject design). Twelve healthy men participated in study 2 (within-subject design). TWA and PEP were derived from ECG and impedance cardiography, respectively.
Results:
Epinephrine shortened PEP and induced statistically significant biphasic TWA changes. However, although the two alpha2-drugs significantly affected PEP as expected, no effects on TWA could be detected.
Conclusion:
PEP is better suited to reflect SNS activity changes than TWA.
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