Sympathetic Nerve Activity During Hypoglycemia and Exercise

• ClinicalTrials.gov Identifier: NCT00608348
• Recruitment Status: Completed
• First Posted: February 6, 2008
• Last Update Posted: June 10, 2015
• Sponsor: Vanderbilt University
• Information provided by (Responsible Party): Steve Davis, Vanderbilt University

Study Description

Brief Summary:

The purpose of this study is to determine if either hypoglycemia or exercise cause differential responses in muscle and skin sympathetic nerve activity.

Condition or disease	Intervention/treatment	Phase
Diabetes Mellitus	Procedure: Hyperinsulinemic glucose clamp procedures; Procedure: moderate exercise	Not Applicable

Detailed Description:

The body has defensive responses to correct low blood sugar (hypoglycemia). A vital component of this response is release of glucagon and activation of the sympathetic nervous system, which provides the means for raising blood glucose levels towards normal. We can measure circulating hormones indicating the level of these responses, but additionally, sympathetic nervous system responses can be measured directly. We can measure the sympathetic nerve activity that controls blood flow to muscles (MSNA) and blood flow and sweating to skin (SSNA). The purpose of this study is to determine if either hypoglycemia or exercise cause differential responses in muscle and skin sympathetic nerve activity. We would also like to determine what the sympathetic response is to cycling exercise with insulin and normal blood sugar. Therefore, we would like to test the sympathetic responses to insulin with normal blood glucose, hypoglycemia, and during exercise bouts and normal blood glucose, with or without insulin.

Study Design

• Study Type: Interventional (Clinical Trial)
• Actual Enrollment: 36 participants
• Allocation: Randomized
• Intervention Model: Factorial Assignment
• Masking: None (Open Label)
• Official Title: Sympathetic Nerve Activity During Hypoglycemia and Exercise
• Study Start Date: April 2002
• Actual Primary Completion Date: July 2008
• Actual Study Completion Date: July 2008

Arms and Interventions

Arm	Intervention/treatment
Experimental: 1; Hyperinsulinemic euglycemic or hypoglycemic clamp with Muscle and skin sympathetic nerve activity recording in arm and/or leg	Procedure: Hyperinsulinemic glucose clamp procedures; 2 hours of either euglycemic or hypoglycemic glucose clamping
Experimental: 2; Exercise with insulin or no insulin infused with muscle and skin sympathetic nerve activity measurements	Procedure: moderate exercise; 90 minutes of moderate exercise with either hyperinsulinemia or euinsulinemia

Outcome Measures

Primary Outcome Measures :

1. Muscle sympathetic nerve activity [ Time Frame: 2 hours ]

Eligibility Criteria

• Ages Eligible for Study: 18 Years to 40 Years (Adult)
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: Yes

Criteria

Inclusion Criteria:

• 36 Healthy male and female subjects (18 males and 18 females) aged 18-40 yr
• All potential volunteers will have routine blood test to screen for hepatic, renal, and hematological abnormalities
• Body mass index ≤30kg · m-2
• Normal bedside autonomic function
• Female volunteers of childbearing potential will undergo HCG pregnancy test at screening and again on the study day.

Exclusion Criteria:

• Pregnant women
• Subjects unable to give voluntary informed consent
• Subjects on anticoagulant drugs or anemic
• Subjects with a recent medical illness
• Subjects with a history of hypertension, heart disease or cerebrovascular disease
• Subjects with known liver or kidney disease
• Subjects with recent weight loss or consuming a low carbohydrate diet

Contacts and Locations

Locations

United States, Tennessee

Vanderbilt University

Nashville, Tennessee, United States, 37232

Sponsors and Collaborators

Vanderbilt University

Investigators

• Principal Investigator: Stephen N. Davis, MD; Vanderbilt University

More Information

• Responsible Party: Steve Davis, Chairman of Medicine, Vanderbilt University
• ClinicalTrials.gov Identifier: NCT00608348
• Other Study ID Numbers: IRB#020777-SNA during hypo/ex
• First Posted: February 6, 2008
• Last Update Posted: June 10, 2015
• Last Verified: June 2015

Keywords provided by Steve Davis, Vanderbilt University:

exercise; hypoglycemia; sympathetic nerve activity

Additional relevant MeSH terms:

Hypoglycemia; Glucose Metabolism Disorders; Metabolic Diseases