In vivo cerebral incorporation of radiolabeled fatty acids after acute unilateral orbital enucleation in adult hooded Long-Evans rats
- National Institutes of Health, Bethesda, MD (United States)
We examined effects of acute unilateral enucleation on incorporation from blood of intravenously injected unsaturated [1-{sup 14}C]arachidonic acid ([{sup 14}C]AA) and [1-{sup 14}C]docosahexaenoic acid ([{sup 14}C]DHA), and of saturated [9,10-{sup 3}H]palmitic acid ([{sup 3}H]PA), into visual and nonvisual brain areas of awake adult Long-Evans hooded rats. Regional cerebral metabolic rate for glucose (rCMR{sub glc}) values also were assessed with 2-deoxy-D-[1-{sup 14}C]glucose ([{sup 14}C]DG). One day after unilateral enucleation, an awake rat was placed in a brightly lit visual stimulation box with black and white striped walls, and a radiolabeled fatty acid was infused for 5 min or [{sup 14}C]DG was injected as a bolus. [{sup 14}C]DG also was injected in a group of rats kept in the dark for 4 h. Fifteen minutes after starting an infusion of a radiolabeled fatty acid, or 45 min after injecting [{sup 14}C]DG, the rat was killed and the brain was prepared for quantitative autoradiography. Incorporation coefficients k* of fatty acids, or rCMR{sub glc} values, were calculated in homologous brain regions contralateral and ipsilateral to enucleation. As compared with ipsilateral regions, rCMR{sub glc} was reduced significantly (by as much as -39%) in contralateral visual areas, including the superior colliculus, lateral geniculate body, and layers I, IV, and V of the primary (striate) and secondary (association, extrastriate) visual cortices. These results indicate that enucleation acutely reduces neuronal activity in contralateral visual areas of the awake rat and that the reductions are coupled to reduced incorporation of unsaturated fatty acids into sn-2 regions of phosphatidylcholine, phosphatidylinositol, and phosphatidylethanolamine. Reduced fatty acid incorporation likely reflects reduced activity of phospholipases A{sub 2} and/or phospholipase C. 65 refs., 5 figs., 5 tabs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 54860
- Journal Information:
- Journal of Cerebral Blood Flow and Metabolism, Vol. 14, Issue 2; Other Information: PBD: Mar 1994
- Country of Publication:
- United States
- Language:
- English
Similar Records
Metabolic activity in striate and extrastriate cortex in the hooded rat: contralateral and ipsilateral eye input
Differential blood-brain barrier permeabilities to (/sup 14/C)sucrose and (/sup 3/H)inulin after osmotic opening in the rat