[Subcellular distribution of the phosphate-activated glutaminase activity in the visual analyzer of the brain during...

The level of general activity of phosphate-activated glutaminase (PAG) on the 1st postnatal day was higher in heavy and light synaptosomes of the exterior geniculate body (EGB) and lower--in the superior colliculus (SC) and visual cortex (field 17); in the subfractions of synaptic mitochondria (E) the general activity of the enzyme was higher in EGB and lower in the visual cortex (field 17) and SC. The level of general activity of the enzyme in the subcellular formations and certain formations of the visual analyzer on the 1st postnatal day was different. This difference varied in the course of postnatal development of the visual system in dogs. The PAG general activity in the subfractions of light (C), heavy (D) synaptosomes, synaptic mitochondria of the membranous enzymes and small synaptosomes sharply enhanced in the visual cortex (field 17) of SC and EGB from the 1st to the 12-14th postnatal days, the subfractions C and D of the visual cortex (field 17) showing the highest degree of the enzyme activity up to the 45th day. SC and EGB subfractions showed a considerable decrease in the enzyme activity of dogs aged 3 months; this peculiarity persisted up to the 6-month age in the above formations, especially in the subfractions B, C, D and E. Dogs aged 1 year exhibited a sharper decrease in the general activity of the enzyme of formations C, D, E in EGB and SC. It was established that with an advance of age the general activity of the enzyme in myelin subfractions (A) mostly increased, especially in the visual cortex (field 17) and EGB of dogs aged 1 year and in SC of dogs aged 6 months.