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The Effects of High Glucose Concentrations on Cerebral Myogenic Tone of Control and Type II Diabetic Rats
Author(s) -
Kelly Aisha Imani,
Elgebaly Mostafa M.,
Ergul Adviye
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.613.18
Subject(s) - myogenic contraction , medicine , endocrinology , vasodilation , perfusion , blood flow , cerebral blood flow , diabetes mellitus , vascular smooth muscle , blood pressure , middle cerebral artery , skeletal muscle , blood vessel , cerebral arteries , chemistry , smooth muscle , ischemia
Changes in cerebrovascular myogenic reactivity can hamper autoregulatory mechanisms responsible for maintaining blood flow to the brain. Previous studies report that in vitro exposure to high glucose reduces the myogenic tone of isolated cerebral arteries from non‐diabetic animals and causes vasodilatation. However, the effect of buffer glucose concentration on myogenic reactivity of isolated cerebral vessels from diabetic animals with preexisting vascular disease is unknown. We hypothesized that myogenic responses of the middle cerebral artery (MCA) to increasing perfusion pressure in normal and high glucose containing buffer differ in control and diabetic animals. MCAs from aged‐matched Wistar (n= 10) and type II diabetic Goto‐Kakizaki (GK) rats (n=3,4) were placed in buffer containing either 5mM or 25mM glucose and pressurized using an arteriograph system. All groups maintained their myogenic properties across the autoregulatory range (40‐120 mmHg) and constricted in response to increasing pressure. At 80 mmHg, diabetic MCAs in 5mM glucose had higher tone than control group (29.3± 5.7% vs 17.2±3.5%). GK rats tended to have lower myogenic tone in 25mM glucose whereas control animals showed increased tone as compared to 5mM glucose conditions across the pressure range. There was no difference in lumen diameter or media thickness among the groups. Therefore, in vitro vascular reactivity is affected by buffer glucose concentration; adjusting it to reflect animal blood glucose levels may allow better evaluation of myogenic reactivity. NIH DK074385 , DK074385 ‐04S1 and AHA 0740002NM