In vivo imaging of brain incorporation of fatty acids and of 2-deoxy-d-glucose demonstrates functional and structural neuroplastic effects of chronic unilateral visual deprivation in rats

doi:10.1016/0006-8993(95)00069-3

Brain Research

Volume 679, Issue 1, 8 May 1995, Pages 110-122

https://doi.org/10.1016/0006-8993(95)00069-3 Get rights and content

Abstract

Regional cerebral ‘incorporation coefficients’k^* of each of 3 labeled long-chain fatty acids — [9,10-³H]palmitate ([³H]PA), [1-¹⁴C]arachidonate ([¹⁴C]AA) and [1-¹⁴C]docosahexaenoate ([¹⁴C]DHA) — were measured using quantitative autoradiography in 11 bilateral brain visual areas of 3.5-month-old awake, hooded, Long-Evans rats, and were compared with regional cerebral metabolic rates for glucose (rCMR_glc). The rats, which had undergone unilateral orbital enucleation at 15 days of age, were studied either in the dark with eyelids of the intact eye sutured, or when stimulated in a light ☐ with the intact eye open. rCMR_glc did not differ between homologous contralateral and ipsilateral visual areas in the dark or during stimulation, but was elevated bilaterally by 25% or more in many visual areas during stimulation compared with dark. Contralateral compared with ipsilateralk^* was lower for each fatty acid tracer in superficial gray of the superior colliculus (in dark and during stimulation) and dorsal nucleus of lateral geniculate body (during stimulation). In the dark,k^* for [³H]PA was correlated significantly with rCMR_glc for the 22 visual areas studied, whereas during stimulationk^* for [¹⁴C]AA was correlated with rCMR_glc. These results suggest that central neuroplastic changes following chronic unilateral enucleation are accompanied by reduced incorporation of [³H]PA, [¹⁴C]AA and [¹⁴C]DHA into contralateral brain areas that normally receive crossed retinofugal fibers, and by symmetry of rCMR_glc in the dark but increased bilateral symmetrical responsiveness of rCMR_glc to visual stimulation of the intact eye.

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Brain membrane phospholipids are highly enriched with the polyunsaturated fatty acids (PUFAs), docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6), which participate in neurotransmission [1,2], gene transcription and the regulation of brain immunity [3–5].
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Arachidonic acid (AA, 20:4n-6), an important second messenger, is released from membrane phospholipid following receptor mediated activation of phospholipase A₂ (PLA₂). This signaling process can be imaged in brain as a regional brain AA incorporation coefficient K*.
K* will be increased in brain visual areas of subjects submitted to visual stimulation.
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During flash stimulation at 2.9 Hz or 7.8 Hz vs. 0 Hz, K* was increased significantly by 2.3–8.9% in Brodmann areas 17, 18 and 19, and in additional frontal, parietal and temporal cortical regions. rCBF was increased significantly by 3.1–22%, often in comparable regions. Increments at 7.8 Hz often exceeded those at 2.9 Hz for both K* and rCBF. Decrements in both parameters also were produced, particularly in frontal brain regions.
AA plays a role in signaling processes provoked by visual stimulation, since visual stimulation at flash frequencies of 2.9 and 7.8 Hz compared to 0 Hz modifies both K* for AA and rCBF in visual and related areas of the human brain. The two-stimulus condition paradigm of this study might be used with PET to image effects of other functional activations and of drugs on brain signaling via AA.

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¹: Present Address: Department of Neurosurgery, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113, Japan.

²: Food and Drug Administration/CDER, HFD-120, 5600 Fishers Lane, Rockville, MD 20857, USA.

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In vivo imaging of brain incorporation of fatty acids and of 2-deoxy-d-glucose demonstrates functional and structural neuroplastic effects of chronic unilateral visual deprivation in rats

Abstract

Trends Neurosci.

Brain Res.

Exp. Neurol.

J. Biol. Chem.

J. Biol. Chem.

Brain Res.

Brain Res.

Brain Res.

Neurosci. Lett.

Brain Res.

Exp. Neurol.

Brain Res. Rev.

Brain Res.

Brain Res.

Exp. Neurol.

Exp. Neurol.

Dev. Brain Res.

Exp. Neurol.

Physiol. Behav.

Neuroscience

Exp. Neurol.

Brain Res.

Brain Res.

Ann. Anat.

Brain incorporation of11C-arachidonate in normocapnic and hypercapnic monkeys: a PET study

Abstr. Soc. Neurosci.

Visual pigments of some common laboratory manuals

Nature

Enzymic pathways of phospholipid metabolism in the nervous system

Adrenergic and cholinergic stimulation of arachidonate and phosphatidate metabolism in cultured astroglial cells

Neurochem. Res.

Arecoline-stimulated brain incorporation of intravenously administered fatty acids in unanesthetized rats

J. Neurochem.

Intravenous injection of [1-14C]arachidonate to examine regional brain lipid metabolism in unanesthetized rats

J. Neurosci. Res.

Abacus Concepts, StatView II

The effect of monocular deprivation on the synaptic contacts of the visual cortex

J. Neurobiol.

Brain incorporation of¹¹C-arachidonate in normocapnic and hypercapnic monkeys: a PET study

Intravenous injection of [1-¹⁴C]arachidonate to examine regional brain lipid metabolism in unanesthetized rats