Biomaterial Database

Low zinc status in guinea pigs impairs calcium uptake by brain synaptosomes. 1994

J D Browning, and B L O'Dell

Department of Biochemistry, University of Missouri, Columbia 65211.

Zinc deficiency results in defective central nervous system function and in peripheral neuropathy. Calcium serves as second messenger in both pre- and postsynaptic membranes. Presynaptic uptake of calcium occurs via voltage-gated channels, whereas postsynaptic uptake occurs by way of a glutamate-activated channel, the N-methyl-D-aspartate (NMDA) receptor-channel. This study was designed to determine the effect of zinc status on calcium uptake by synaptic membranes prepared from guinea pigs deprived of zinc. Within each group of three guinea pigs, one animal was allowed to consume a low zinc (< 1 mg/kg) diet ad libitum (-ZN), one an adequate zinc (100 mg/kg) diet ad libitum (+AL), and one the adequate zinc diet restricted (+RF). When the -ZN guinea pig within a group developed clinical signs of deficiency, synaptosomes were prepared from brain cortices and calcium uptake measured by use of 45Ca. Both high potassium- and glutamate-stimulated calcium uptakes by synaptosomes from zinc-deficient guinea pigs were significantly lower than those of controls, with the glutamate-stimulated uptake 40% lower. In vitro addition of either magnesium or zinc resulted in lower uptake in synaptosomes from all dietary groups. Regardless of in vitro conditions, calcium uptake was impaired by zinc deficiency. The impaired function of calcium channels may explain the neurological disturbances observed in zinc-deficient animals.

UI	MeSH Term	Description	Entries
D008274	Magnesium	A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D008297	Male		Males
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D002540	Cerebral Cortex	The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulci. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.	Allocortex,Archipallium,Cortex Cerebri,Cortical Plate,Paleocortex,Periallocortex,Allocortices,Archipalliums,Cerebral Cortices,Cortex Cerebrus,Cortex, Cerebral,Cortical Plates,Paleocortices,Periallocortices,Plate, Cortical
D005260	Female		Females
D005971	Glutamates	Derivatives of GLUTAMIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the 2-aminopentanedioic acid structure.	Glutamic Acid Derivatives,Glutamic Acids,Glutaminic Acids
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013574	Synaptosomes	Pinched-off nerve endings and their contents of vesicles and cytoplasm together with the attached subsynaptic area of the membrane of the post-synaptic cell. They are largely artificial structures produced by fractionation after selective centrifugation of nervous tissue homogenates.	Synaptosome
D015032	Zinc	A metallic element of atomic number 30 and atomic weight 65.38. It is a necessary trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Zinc deficiency is associated with ANEMIA, short stature, HYPOGONADISM, impaired WOUND HEALING, and geophagia. It is known by the symbol Zn.