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Homeostasis of Brain and Cerebrospinal Fluid Calcium Concentrations During Chronic Hypo‐and Hypercalcemia
Author(s) -
Murphy Vincent A.,
Smith Quentin R.,
Rapoport Stanley I.
Publication year - 1986
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1986.tb13082.x
Subject(s) - extracellular fluid , cerebrospinal fluid , extracellular , endocrinology , medicine , calcium , homeostasis , calcium metabolism , chemistry , blood–brain barrier , central nervous system , biochemistry
Three‐week‐old rats were made hypocalcemic or hypercalcemic by being fed diets low or high in Ca. Both total and ionized [Ca]s in the plasma decreased about 40% and remained depressed for 4 weeks in rats fed a low‐Ca diet. Plasma [Ca]s in rats fed a high‐Ca diet increased by 30% and remained elevated for 7 weeks. After 8 weeks on the diets, cerebrospinal fluid (CSF) [Ca] changed by <30% whereas brain [Ca] changed by <20% of the chronic changes in plasma ionized [Ca]. Assuming a brain extracellular volume of 20% and noting that brain extracellular volume equilibrates freely with CSF, the findings demonstrate only small perturbations in the Ca content of the brain cellular compartment during sustained hypo or hypercalcemia. Partial regulation of CSF and brain extracellular Ca suggests a role for the blood‐brain barrier in regulating CNS [Ca] during chronic changes in plasma [Ca].