Pathophysiology of pH and Ca2+ in bloodstream and brain.

Published

Journal Article

The highlights of the literature and our work on tetany and hyperventilation are reviewed. Our studies concern the following: (1) the changes of [Ca2+] in circulating plasma caused by respiratory and "metabolic" acidosis and alkalosis; (2) critical plasma [Ca2+] levels associated with signs of tetany and neuromuscular blockade; (3) changes in cerebral [Ca2+]o caused by hypo- and hyper-calcaemia, and the changes in cerebral [Ca2+]o and pHo caused by acute systemic acidosis and alkalosis; and (4) effects of changing [Ca2+]o and pHo levels on synaptic transmission in hippocampal formation. Our main conclusions are (1) changes of plasma [Ca2+] caused by "metabolic" pH changes are greater than those associated with varying CO2 concentration; (2) acute systemic [Ca2+] changes are associated with small cerebral [Ca2+]o changes; (3) the decreases in systemic and cerebral [Ca2+]o caused by hyperventilation are too small to account for the signs and symptoms of hypocapnic tetany; (4) moderate decrease of [Ca2+]o depresses and its increase enhances synaptic transmission in hippocampal formation; and (5) H+ ions in extracellular fluid have a weak depressant effect on neuronal excitability. CO2 is a strong depressant, which is only partly explained by the acidity of its solution. CO2 concentration is a significant factor in controlling cerebral function.

Full Text

Duke Authors

Cited Authors

  • Somjen, GG; Allen, BW; Balestrino, M; Aitken, PG

Published Date

  • May 1987

Published In

Volume / Issue

  • 65 / 5

Start / End Page

  • 1078 - 1085

PubMed ID

  • 3113705

Pubmed Central ID

  • 3113705

International Standard Serial Number (ISSN)

  • 0008-4212

Digital Object Identifier (DOI)

  • 10.1139/y87-169

Language

  • eng

Conference Location

  • Canada