Thalamic activation during slightly subphysiological glycemia in humans.

Journal Article (Journal Article)

OBJECTIVE: The central nervous system mechanisms of defenses against falling plasma glucose concentrations, and how they go awry and result in iatrogenic hypoglycemia in diabetes, are not known. Hypoglycemic plasma glucose concentrations of 55 mg/dL (3.0 mmol/L) cause symptoms, activate glucose counterregulatory systems, and increase synaptic activity in a network of brain regions including the dorsal midline thalamus in humans. We tested the hypothesis that slightly subphysiological plasma glucose concentrations of 65 mg/dL (3.6 mmol/L), which do not cause symptoms but do activate glucose counterregulatory systems, also activate brain synaptic activities. RESEARCH DESIGN AND METHODS: We measured relative regional cerebral blood flow (rCBF), an index of synaptic activity, in predefined brain regions with [(15)O]water positron emission tomography, symptoms, and plasma epinephrine and glucagon concentrations during a 2-h euglycemic (90 mg/dL) to hypoglycemic (55 mg/dL) clamp (n = 20) or a 2-h euglycemic to slight subphysiological (65 mg/dL) clamp (n = 9) in healthy humans. RESULTS: Clamped plasma glucose concentrations of 65 mg/dL did not cause hypoglycemic symptoms, but raised plasma epinephrine and glucagon concentrations and increased rCBF (P = 0.007) only in the dorsal midline thalamus. CONCLUSIONS: Slightly subphysiological plasma glucose concentrations increase synaptic activity in the dorsal midline thalamus in humans.

Full Text

Duke Authors

Cited Authors

  • Arbeláez, AM; Rutlin, JR; Hershey, T; Powers, WJ; Videen, TO; Cryer, PE

Published Date

  • December 2012

Published In

Volume / Issue

  • 35 / 12

Start / End Page

  • 2570 - 2574

PubMed ID

  • 22891254

Pubmed Central ID

  • PMC3507561

Electronic International Standard Serial Number (EISSN)

  • 1935-5548

Digital Object Identifier (DOI)

  • 10.2337/dc12-0297

Language

  • eng

Conference Location

  • United States