Intraocular injection of APB decreases the metabolic response of the rat superior colliculus.
The functional activity of the superior colliculus (SC) following flash stimulation was examined by means of 2-deoxyglucose (2DG) method in monocularly enucleated Long-Evans rats intraocularly injected with a solution of 2-amino-4-phosphonobutyric acid (APB), able to silence the ON retinal activity. After APB injection SC layers recipient of retinal axons suffered a sustained 2DG decrease as compared to controls. Moreover, whereas glucose utilization in normal rat SC appears unevenly distributed and closely related to retinal axon density, by contrast, APB-treated rats showed a rather uniform metabolic activity throughout the SC surface. Furthermore, we calculated the 2DG uptake percentage reduction in 12 SC loci of APB rats in respect to homologous loci of controls: glucose utilization decreases at the loci largely differ from each other, showing that retinal axons carrying ON activity are dispersed over the SC in a mosaic pattern. Thus, the SC metabolic map should be representative of its retinotopic organization which, in turn, depends on the asymmetric distribution in the rat's retina of W-like as well as of other ganglion cell types.
Biral
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GP
Istituto di Fisiologia Umana, Modena, Italy.
Ferrari
R
R
Benassi
C
C
Fonda
S
S
D000613:Aminobutyrates / Q000008:administration & dosage* / Q000494:pharmacology; D000818:Animals; D003847:Deoxyglucose / Q000378:metabolism; D007267:Injections; D008297:Male; D009799:Ocular Physiological Phenomena; D010775:Photic Stimulation; D051381:Rats; D011919:Rats, Inbred Strains; D012160:Retina / Q000187:drug effects / Q000502:physiology; D013477:Superior Colliculi / Q000378:metabolism*; D015349:Vision, Monocular / Q000502:physiology
D000613:Aminobutyrates; D003847:Deoxyglucose; C012729:2-amino-4-phosphonobutyric acid