Related Experiment Videos
Glucose increases rat plasma norepinephrine levels by direct action on the brain
1Neurology Service, Department of Veterans Affairs Medical Center, East Orange, New Jersey 07019.
The American Journal of Physiology
|December 1, 1991
Summary
Glucose directly activates the sympathetic nervous system (SNS) via the brain. Studies show brain glucose action increases norepinephrine levels, suggesting a selective SNS response.
Area of Science:
- Neuroendocrinology
- Autonomic Nervous System Research
- Metabolic Signaling
Background:
- The sympathetic nervous system (SNS) regulates crucial physiological functions.
- The role of direct brain glucose sensing in SNS activation remains unclear.
- Understanding this pathway is vital for metabolic and cardiovascular health.
Purpose of the Study:
- To investigate if glucose selectively activates the SNS through direct brain action.
- To differentiate between central and peripheral effects of glucose on SNS and adrenal medulla.
Main Methods:
- Administered intracarotid and intravenous glucose injections and infusions in a controlled study.
- Measured plasma norepinephrine (NE) and epinephrine (Epi) as indicators of SNS and adrenal medullary activity.
- Utilized mannitol as an equiosmolar control to isolate glucose-specific effects.
Main Results:
- Intracarotid glucose boluses increased plasma NE without affecting Epi, indicating selective SNS activation.
- Intravenous glucose boluses showed delayed NE responses compared to direct intracarotid administration.
- Intracarotid glucose infusions, even without altering blood glucose levels, elevated NE, supporting a direct brain mechanism.
Conclusions:
- Glucose can selectively activate the sympathetic nervous system via direct action on the brain.
- This central mechanism contributes to delayed SNS activation independent of systemic metabolic changes.
- Findings elucidate a novel pathway for glucose-mediated autonomic regulation.