title: Developmental studies of the compartmentalization of water and electrolytes in the choroid plexus of the neonatal rat brain.
abstract: Rats of various postnatal ages were utilized to study developmental changes in the distribution of Na, K and H2O between the various compartments of the lateral ventricular plexus (LVP). During the 3 weeks after birth, as the LVP grows from 0.5 to 0.8 mg, there is a significant increase in plexus K which is accompanied by a progressive decrease in Na and H2O. Also, during this postnatal period the decrease in [3h]inulin space in the plexus is proportional to the decrease in the Na space. Between 3 weeks and adulthood, the [3h]inulin and Na spaces are both augmented to a similar extent; moreover, during this same period of development there is a trebling of the residual [51cr]erythrocyte volume. Despite the substantial changes in the volume of the extracellular fluid and of the residual blood in the plexus with age, the calculated concentrations (mEquiv./kg H2O) of choroid cell Na (30-35) and K (145-155) are similar for all ages investigated. The derived data for cellular ionic concentration, together with the analysis of the ionic concentration gradients (cerebrospinal fluid/plasma H2O), suggest that the transport mechanism which translocates Na and K across the choroidal membrane is operative as early as 3-4 days postnatal. The important role of the choroid plexus in central nervous system homeostasis is discussed in relation to the developing brain.
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000254:growth & development; D001923:Brain Chemistry; D002831:Choroid Plexus / Q000098:blood supply / Q000254:growth & development* / Q000378:metabolism; D004848:Epithelium / Q000032:analysis; D004912:Erythrocytes / Q000032:analysis; D005110:Extracellular Space; D007444:Inulin; D009929:Organ Size; D011188:Potassium / Q000097:blood / Q000134:cerebrospinal fluid / Q000378:metabolism; D051381:Rats; D012964:Sodium / Q000097:blood / Q000134:cerebrospinal fluid / Q000378:metabolism; D014882:Water-Electrolyte Balance
chemical_list: D007444:Inulin; D012964:Sodium; D011188:Potassium