Methyldopa (L-alpha-Methyl-3,4-dihydroxyphenylalanine) is a catecholamine used
as an antihypertensive agent.1 Alpha-Methyldopa is not used as frequently
anymore due to side effects, but it is still used especially in developing countries
due to its low cost. Indications are mostly for the management of pregnancyinduced
hypertension (PIH), as it is relatively safe in pregnancy compared to other
antihypertensive drugs. This project is intended to increase the already-existing
knowledge base of the mechanism of pharmacological action and to stimulate
further investigation through research.
The sympathetic nervous system is a division of the autonomic nervous system
and it is responsible for the “flight-or-fight” response. It is involuntary and constantly
active to maintain homeostasis in the human body. Sympathetic responses include
an increase in heart rate, blood pressure and cardiac output, dilation of pupils and
bronchioles, constriction of blood vessels, contraction of sphincters and inhibition
of gut motility and secretions.
The purpose of this study is to evaluate the activity of the sympathetic nervous
system of volunteers by three different techniques (QT interval and Heart rate
variability and Skin conductance) after a week of a bi-daily dosage of alphamethyldopa.
All volunteers received either 250mg alpha-methyldopa orally or a placebo tablet in
a randomized, double blind, placebo controlled study design. The correlation
between the following techniques was also evaluated: Skin conductance as
measured by the ProComp Infiniti Biofeedback apparatus, QT interval on ECG and
HRV measured with Viport apparatus. A salivary sample was collected to evaluate
the effect of alpha-methyldopa on salivary cortisol using an ELISA kit for analysis.