Recent studies suggest that moderate hypoglycemia impairs brainstem function in normal humans and rats. To examine whether diabetes alters this response, simultaneous auditory-evoked potentials were recorded directly from the inferior colliculus (IC) and from the brainstem before and after controlled hypoglycemia (clamp) in awake insulin-dependent diabetic BB/Wor rats. Hyperglycemic diabetic animals were studied either during hyperinsulinemic euglycemia (5.6 mmol/l, n = 4) or mild hypoglycemia (3.5 mmol/l, n = 9). Nondiabetic controls were also studied at 3.5 mmol/l (n = 7) and at 2.8 mmol/l (n = 6). Brainstem function was not affected during euglycemia in diabetic rats. However, when plasma glucose was lowered to 3.5 mmol/l, the diabetic rats showed a 10% delay in IC evoked potential (ICEP) latency, whereas nondiabetic animals did not. This occurred despite similar counterregulatory hormones in both groups. The brainstem auditory-evoked potential (BAEP) localized the defect in the diabetic group to an area in or near the IC. When glucose levels were lowered to 2.8 mmol/l, however, brain function was impaired in nondiabetic rats as well. Again the defect was restricted to an area in or near the IC. We conclude that mild hypoglycemia causes a functional impairment in the IC region of the brainstem in both nondiabetic and diabetic rats. However, in the diabetic rats, this alteration occurs after a less pronounced hypoglycemic stimulus. Our findings suggest that chronic hyperglycemia leads to metabolic adaptions that render the diabetic brain more susceptible to mild hypoglycemia.
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Original Articles|
August 01 1995
Brainstem Dysfunction Is Provoked by a Less Pronounced Hypoglycemic Stimulus in Diabetic BB Rats Free
Ralph J Jacob;
Ralph J Jacob
Yale University School of Medicine, Department of Inernal Medicine
, New Haven, Connecticut
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Andrew B Weber;
Andrew B Weber
Yale University School of Medicine, Department of Inernal Medicine
, New Haven, Connecticut
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James Dziura;
James Dziura
Yale University School of Medicine, Department of Inernal Medicine
, New Haven, Connecticut
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Jennifer Morgen;
Jennifer Morgen
Yale University School of Medicine, Department of Inernal Medicine
, New Haven, Connecticut
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Robert S Sherwin
Robert S Sherwin
Yale University School of Medicine, Department of Inernal Medicine
, New Haven, Connecticut
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Address correspondence and reprint requests to Ralph J. Jacob, MS, Yale University School of Medicine, Department of Internal Medicine/Endocrinology, 333 Cedar St., New Haven, CT 06510.
1
BAEP, brainstem auditory-evoked potential; CNS, central nervous system; IC, inferior colliculus; ICEP, inferior colliculus evoked potential; IDDM, insulin-dependent diabetes mellitus.
Diabetes 1995;44(8):900–905
Article history
Received:
November 17 1994
Revision Received:
April 05 1995
Accepted:
April 05 1995
PubMed:
7621994
Citation
Ralph J Jacob, Andrew B Weber, James Dziura, Jennifer Morgen, Robert S Sherwin; Brainstem Dysfunction Is Provoked by a Less Pronounced Hypoglycemic Stimulus in Diabetic BB Rats. Diabetes 1 August 1995; 44 (8): 900–905. https://doi.org/10.2337/diab.44.8.900
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