| Abstract: | This review emphasizes the importance of strong ions in the regulation of cerebrospinal fluid (CSF) acid-base balance. In a solution like CSF that is devoid of nonbicarbonate buffers. H+] and HCO-3] are dependent variables, the independent variables being the CO2 partial pressure (PCO2) and the strong ion difference. Any measureable changes in CSF HCO-3] and any change in H+] that occur independent of changes in PCO2 must be accompanied by, if not caused by, changes in strong ions. The role of H+ and HCO-3 vs. strong ions in the ionic mechanisms of CSF acid-base regulation is unknown. For example, these mechanisms could depend only on changes in strong ions that accompany acid-base disorders, or they could be triggered by changes in H+] or PCO2. These ideas are presented within the context of current concepts concerning the relationship of CSF to brain interstitial fluid (ISF) and the importance of choroid plexus and blood-brain barrier mechanisms in determining CSF and ISF ionic composition. Studies concerning CSF strong ions in normal and abnormal acid-base states are reviewed. |
