Related Experiment Video
Updated: Jun 27, 2026
07:35
Hyperglycemic Clamp and Hypoglycemic Clamp in Conscious Mice
Published on: January 26, 2024
Antecedent hypoglycemia impairs autonomic cardiovascular function: implications for rigorous glycemic control.
Gail K Adler1, Istvan Bonyhay, Hannah Failing
1Division of Endocrinology, Diabetes, and Hypertension, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
Diabetes
|December 6, 2008
Summary
Prior hypoglycemia impairs autonomic cardiovascular responses, including baroreflex sensitivity and sympathetic nerve activity. This finding raises concerns about hypoglycemia
Area of Science:
- Cardiovascular Physiology
- Autonomic Nervous System Function
- Metabolic Regulation
Background:
- Intensive glycemic control in diabetes can increase hypoglycemia risk.
- Hypoglycemia may impair the body's protective responses to future low blood sugar events.
- Autonomic dysfunction is linked to increased mortality in cardiovascular disease.
Purpose of the Study:
- To investigate if prior exposure to hypoglycemia impairs cardiovascular autonomic function.
- To test the hypothesis that hypoglycemia leads to attenuated autonomic responses.
Main Methods:
- Twenty healthy subjects underwent autonomic function testing over two 3-day inpatient visits.
- A hyperinsulinemic-hypoglycemic clamp was used to induce low blood sugar.
- Sympathetic, parasympathetic, and baroreflex functions were measured before and after hypoglycemia exposure.
Main Results:
- Antecedent hypoglycemia significantly reduced baroreflex sensitivity (P = 0.03).
- Muscle sympathetic nerve activity response to hypotension was decreased post-hypoglycemia (P < 0.01).
- Plasma norepinephrine response to lower body negative pressure was attenuated (P < 0.001).
Conclusions:
- Prior hypoglycemia attenuates baroreflex sensitivity and sympathetic responses to hypotensive stress.
- Impaired autonomic function following hypoglycemia may have significant implications for cardiovascular health.
- These findings highlight potential risks associated with recurrent hypoglycemia, particularly in at-risk populations.
Related Concept Videos
01:26Hypoglycemia
Hypoglycemia is a blood glucose level below 70 mg/dL. It commonly occurs in individuals using insulin or insulin-secreting drugs, but may also arise in non-diabetic conditions. People with type 1 diabetes are at the highest risk because they depend on exogenous insulin. People with type 2 diabetes are also at risk, especially when treated with insulin or medications such as sulfonylureas, which increase insulin release regardless of blood glucose levels. It develops when insulin levels exceed...
01:29Hyperglycemia
Hyperglycemia is an abnormally high blood glucose level. It is diagnosed by fasting glucose ≥126 mg/dL, 2-hour oral glucose tolerance test (or OGTT) ≥200 mg/dL, random glucose ≥200 mg/dL with symptoms, or HbA1c ≥6.5%. However, HbA1c results may be unreliable in certain conditions, such as anemia or hemoglobinopathies, and the diagnosis should be confirmed unless classic symptoms are present. Postprandial hyperglycemia is typically considered significant when glucose levels exceed 180 mg/dL two...
01:15Hypoglycemia and Glucagon
Without prolonged fasting, healthy individuals maintain blood glucose levels above 3.5 mM due to a well-adapted neuroendocrine counterregulatory system that effectively prevents acute hypoglycemia, a potentially life-threatening condition. The primary clinical scenarios for hypoglycemia encompass diabetes treatment, inappropriate production of endogenous insulin or insulin-like substances by tumors, and the use of glucose-lowering agents in non-diabetic individuals. Notably, hypoglycemia in the...
01:24Type II Diabetes II: Pathophysiology
PathophysiologyType 2 diabetes mellitus (T2DM ) is a chronic metabolic disorder characterized by insulin resistance and progressive pancreatic β-cell dysfunction, leading to impaired glucose homeostasis. It results from interactions among genetic predisposition, environmental factors, and metabolic stressors, such as overnutrition and a sedentary lifestyle.Insulin Resistance and Glucose DysregulationEarly T2DM involves insulin resistance in skeletal muscle, adipose tissue, and the liver.
01:19Type I Diabetes III: Clinical Manifestations
Type 1 diabetes mellitus typically presents with rapid-onset symptoms due to the body’s inability to utilize glucose in the absence of insulin. Since insulin is required for glucose uptake into cells, its deficiency leads to hyperglycemia and cellular energy deprivation, resulting in characteristic clinical features.Polyuria and PolydipsiaOne of the earliest, most prominent symptoms is polyuria (excessive urination). When blood glucose concentrations rise above the renal threshold, the kidneys...
01:22Diabetes Mellitus: Overview and Type I Subtype
Diabetes mellitus is a chronic metabolic disorder characterized by high blood glucose levels due to inadequate insulin production, insulin resistance, or both. The condition affects millions worldwide and can significantly impact their health and quality of life.
Type 1 diabetes is an autoimmune disease in which the immune system mistakenly attacks and destroys the insulin-producing beta cells in the pancreas. As a result, the body is unable to produce sufficient insulin, and individuals with...
Type 1 diabetes is an autoimmune disease in which the immune system mistakenly attacks and destroys the insulin-producing beta cells in the pancreas. As a result, the body is unable to produce sufficient insulin, and individuals with...