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Blood‐brain barrier retains its functional integrity to glutamate in diet‐induced obesity
Author(s) -
Hawkins Richard Albert,
Mokashi Ashwini,
DeJoseph Mary Regina,
Fernstrom John D.
Publication year - 2008
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.22.1_supplement.734.15
Subject(s) - medicine , endocrinology , blood–brain barrier , glutamate receptor , leptin , insulin resistance , insulin , chemistry , diabetes mellitus , diet induced obese , circumventricular organs , obesity , biology , central nervous system , receptor
The consequence of type II diabetes on the permeability of the blood‐brain barrier (BBB) was studied in rats with diet induced obesity. Male Sprague‐Dawley rats were fed a high‐energy diet for a period of 2 weeks whereupon they were separated into three groups on the basis of weight‐gain. The heaviest rats were selected as diet induced obese (DIO), the lightest as diet resistant (DR). The DIO and DR rats continued to be fed the high‐energy diet. The rats of intermediate weight gain were given normal rat chow (Chow). After 6 weeks the rats were infused with a tracer quantity of [14C]glutamate or with [14C]glutamate as well as sufficient glutamate to raise the concentration to more than 2 mM. Autoradiographs of the brains showed that glutamate did not pass the BBB except in circumventricular organs that have fenestrated capillaries. Insulin, leptin and the weight of fat pads (epidymal, mesenteric and retroperitoneal) were also measured. The weight of fat was closely correlated with plasma leptin concentration (r2=0.98) and correlated with plasma insulin concentrations (r2=0.34) The ratio of insulin‐to‐glucose in DIO rats was significantly higher than the Chow or DR rats indicating they were insulin resistant. Thus, in this model of diet‐induced insulin resistance and diabetes, the normal integrity of the BBB toward glutamate was maintained. Sponsored by IGTC.