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NCT Number: NCT00179023

The Autonomic Nervous System and Obesity

In its simplest terms, obesity is the results of a positive balance between food intake and energy expenditure (EE). I.e., we take in more energy, in the form of food, than we expend, e.g., by exercise. In our sedentary society, resting EE accounts for most of total energy expenditure. The sympathetic nervous system (SNS, the one that produces adrenaline) is thought to contribute to resting EE. This conclusion is based on experiments where resting EE is decreased by beta-blockers, high blood pressure medicines that block only one aspect of the sympathetic nervous system. The investigators propose to use a different approach, by using a medication called trimethaphan that produces transient withdrawal of the autonomic nervous system. The investigators will then compare the measured resting EE before and after SNS withdraw and quantify the degree of contribution to the resting EE by the SNS and delineate differences between healthy normal, healthy obese, and patients with autonomic dysfunctions.

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Key information

Conditions

Obesity Autonomic Nervous System Diseases Basal Ganglia Diseases Body Weight Brain Diseases Cardiovascular Diseases Central Nervous System Diseases Hypertension Hypotension Movement Disorders Multiple System Atrophy Nervous System Diseases Nutrition Disorders Nutritional and Metabolic Diseases Overnutrition Overweight Pathological Conditions, Signs and Symptoms Primary Dysautonomias Pure Autonomic Failure Shy-Drager Syndrome Signs and Symptoms Vascular Diseases

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 1

Primary location

Vanderbilt University

Nashville, Tennessee, 37232, United States

About this study

The rationale for this study is that even small alterations to energy metabolism can significantly change energy balance and body weight in the long term. We will test the hypothesis that the sympathetic nervous system (SNS) activity contributes to resting and thermogenic components of energy expenditure (EE).

This study is divided in four different parts: (1), (2), (3), (4).

Part (1): we will gauge the contribution of the sympathetic nervous system to resting energy expenditure, blood pressure, and determine differences between lean, obese, and patients with primary autonomic failure .

Part (2): we will determine the degree of sympathetic blockade by a gradual infusion of the ganglionic blocker trimethaphan.[Part 2 has been closed]

Part (3): we will determine the energy balance in patients with primary autonomic failure.

Part (4): we will determine the contribution of the sympathetic nervous system to lipolysis.[Part 4 has been closed]

Subjects selections*:

For part (1) and (2) we will study six groups of subjects (n = 40 for each group): patients with pure autonomic failure, patients with multiple system atrophy, healthy normal controls (BMI <= 25), obese controls (BMI 30-40) and obese hypertensive (BMI 30-40) and lean hypertensive (BMI 20-28). A time interval of at least 1 week is required for those subjects who wish to participate in part (1) and part (2). For part (3) we will study two groups of subjects (n=12 for each group): patients with autonomic failure, and their age sex-matched sedentary, healthy controls. For part (4) we will study two groups of subjects (n=12 for each group): healthy normal controls (BMI 20-25), obese controls (BMI 30-40).

*Part 2 and 4 have been closed.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy normal (BMI <= 25 Kg/m2), obese (BMI between 30 and 40)volunteers, lean hypertensive (BMI 20-28 Kg/m2), and obese hypertensive (BMI between 30 and 40)
  • Ages 18-60
  • Patients with pure autonomic failure and multiple system atrophy ages 18-80, referred to our service for the diagnosis and treatment of their condition, and their age sex-matched sedentary, healthy controls ages 18-80

Exclusion criteria

  • All medical students
  • Pregnant women
  • Heart failure, symptomatic coronary artery disease, liver impairment, history of stroke or myocardial infarction, glaucoma
  • History of serious allergies or asthma
  • Subjects using beta-blockers

Treatment and study plan

Trimethaphan

Drug

Start dose: 0.05 ml/min (0.5 mg/min), IV infusion. The dose will be increased every 2-4 minutes to 1, 2, 4, and 5 mg/min. Total duration: 1 hour

pseudoephedrine

Drug

30mg tablet,VO. Single dose.

Other names: Sudafed

Primary outcomes

  1. Change in supine systolic blood pressure after achieving complete ganglionic blockade.

    Time frame: 1-2 hour

Secondary outcomes

  1. Change in resting energy expenditure after achieving complete autonomic blockade.

    Time frame: 1-2 hour

Sponsors and collaborators

Lead sponsor

Vanderbilt University

Other

Registry information

Important dates

Study start
2003
Primary completion
2017
Study completion
2017
First posted
Sep 15, 2005
Registry last updated
Mar 1, 2018

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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