title: The influence of CSF calcium and magnesium on the ventilatory response to carbon dioxide during hyperoxia.
abstract: Respiratory responses to inhaled carbon dioxide were measured in anaesthetized cats during perfusion of the ventriculocisternal system with artificial cerebrospinal fluid. A study was performed to evaluate the effect of changes in the magnesium and/or calcium concentration of the CSF on the CO2 response curve which was described as VE = S (PCSF, CO2 -- B). A decrease of S was observed when the magnesium concentration of the perfusion fluid was increased; the B-value remaining the same. The reverse was true down to magnesium concentrations of 0.6 mmol-1-1. Below this concentration S remained the same or decreased; the B-value was lowered. When both the calcium and magnesium concentrations of the CSF were changed, the relation between S and these concentrations could be described as to be proportional to CCAa-CMgb. The effect of changes in the calcium concentration was much more pronounced than comparable changes of the magnesium concentration as reflected by the magnitude of the exponents a and b which were found to be -2.80 (S.D. 0.11) and -0.60 (S.D. 0.03) respectively.
mesh_terms: D000818:Animals; D002118:Calcium / Q000134:cerebrospinal fluid*; D002245:Carbon Dioxide / Q000134:cerebrospinal fluid; D002415:Cats; D008274:Magnesium / Q000134:cerebrospinal fluid*; D008433:Mathematics; D012119:Respiration
chemical_list: D002245:Carbon Dioxide; D008274:Magnesium; D002118:Calcium