Sympathetic Nerve Activity During Hypoglycemia and Exercise

NCT ID: NCT00608348

Last Updated: 2015-06-10

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 36 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2002-04-30
• Study Completion Date: 2008-07-31

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.

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.

Conditions

Diabetes Mellitus

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: FACTORIAL
• Blinding Strategy: NONE

Study Groups

1

Hyperinsulinemic euglycemic or hypoglycemic clamp with Muscle and skin sympathetic nerve activity recording in arm and/or leg

Group Type: EXPERIMENTAL

Hyperinsulinemic glucose clamp procedures

Intervention Type: PROCEDURE

2 hours of either euglycemic or hypoglycemic glucose clamping

2

Exercise with insulin or no insulin infused with muscle and skin sympathetic nerve activity measurements

Group Type: EXPERIMENTAL

moderate exercise

Intervention Type: PROCEDURE

90 minutes of moderate exercise with either hyperinsulinemia or euinsulinemia

Interventions

Hyperinsulinemic glucose clamp procedures

2 hours of either euglycemic or hypoglycemic glucose clamping

Intervention Type: PROCEDURE

moderate exercise

90 minutes of moderate exercise with either hyperinsulinemia or euinsulinemia

Intervention Type: PROCEDURE

Eligibility 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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 40 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Vanderbilt University

OTHER

Sponsor Role: lead

Responsible Party

Steve Davis

Chairman of Medicine

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Stephen N. Davis, MD

Role: PRINCIPAL_INVESTIGATOR

Vanderbilt University

Locations

Vanderbilt University

Nashville, Tennessee, United States

Countries

United States

Other Identifiers

IRB#020777-SNA during hypo/ex

Identifier Type: -

Identifier Source: org_study_id