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Activation of astrocytes in brain of conscious rats during acoustic stimulation: acetate utilization in working brain.
- Source :
- Journal of Neurochemistry; Feb2005, Vol. 92 Issue 4, p934-947, 14p
- Publication Year :
- 2005
-
Abstract
- To evaluate the response of astrocytes in the auditory pathway to increased neuronal signaling elicited by acoustic stimulation, conscious rats were presented with a unilateral broadband click stimulus and functional activation was assessed by quantitative autoradiography using three tracers to pulse label different metabolic pools in brain:[2-<superscript>14</superscript>C]acetate labels the‘small’ (astrocytic) glutamate pool,[1-<superscript>14</superscript>C]hydroxybutyrate labels the‘large’ glutamate pool, and[<superscript>14</superscript>C]deoxyglucose, reflects overall glucose utilization (CMR<subscript>glc</subscript>) in all brain cells. CMR<subscript>glc</subscript> rose during brain activation, and increased activity of the oxidative pathway in working astrocytes during acoustic stimulation was registered with[2-<superscript>14</superscript>C]acetate. In contrast, the stimulation-induced increase in metabolic activity was not reflected by greater trapping of products of[1-<superscript>14</superscript>C]hydroxybutyrate. The[2-<superscript>14</superscript>C]acetate uptake coefficient in the inferior colliculus and lateral lemniscus during acoustic stimulation was 15% and 18% (p < 0.01) higher in the activated compared to contralateral hemisphere, whereas CMR<subscript>glc</subscript> in these structures rose by 66% (p < 0.01) and 42% (p < 0.05), respectively. Calculated rates of brain utilization of blood-borne acetate (CMR<subscript>acetate</subscript>) are about 15–25% of total CMR<subscript>glc</subscript> in non-stimulated tissue and 10–20% of CMR<subscript>glc</subscript> in acoustically activated structures; they range from 28 to 115% of estimated rates of glucose oxidation in astrocytes. The rise in acetate utilization during acoustic stimulation is modest compared to total CMR<subscript>glc</subscript>, but astrocytic oxidative metabolism of‘minor’ substrates present in blood can make a significant contribution to the overall energetics of astrocytes and astrocyte–neuron interactions in working brain. [ABSTRACT FROM AUTHOR]
- Subjects :
- ASTROCYTES
LABORATORY rats
NEURONS
GLUCOSE
NEUROCHEMISTRY
BUTYRATES
Subjects
Details
- Language :
- English
- ISSN :
- 00223042
- Volume :
- 92
- Issue :
- 4
- Database :
- Complementary Index
- Journal :
- Journal of Neurochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 15876478
- Full Text :
- https://doi.org/10.1111/j.1471-4159.2004.02935.x