Cisterna magna microdialysis of sup 22 Na to evaluate ion transport and cerebrospinal fluid dynamics

Journal Article · Sat Jun 01 00:00:00 EDT 1991 · Journal of Neurosurgery; (USA)

DOI:https://doi.org/10.3171/jns.1991.74.6.0965· OSTI ID:5733455

Knuckey, N W; Fowler, A G; Johanson, C E; Nashold, J R; Epstein, M H ^[1]

---

1. Brown Univ./Rhode Island Hospital, Providence (USA)

Microdialysis is used in vivo for measuring compounds in brain interstitial fluid. The authors describe another application of this technique to the central nervous system, namely microprobe dialysis in the cisterna magna to study the dynamics of ion transport and cerebrospinal fluid (CSF) formation in the rat. The choroid plexus is the major source of CSF, which is produced by active transport of Na from blood into the cerebral ventricles. Formation of CSF is directly proportional to the blood-to-CSF transport of Na. By injecting {sup 22}Na into the systemic circulation and quantifying its movement into CSF by microdialysis, one can reliably estimate alterations in the rate of CSF formation. The sensitivity of this system was determined by administering acetazolamide, a standard inhibitor of CSF production. Because acetazolamide is known to decrease CSF formation by 40% to 50%, the cisternal microdialysis system in animals treated with this drug should detect a corresponding decrease in the amount of {sup 22}Na dialyzed. This hypothesis is supported by the {sup 22}Na uptake curves for control versus treated animals: that is, by the acetazolamide-induced average diminution of about 45% in both the rate and extent of tracer accession to dialysate. Bumetanide, a loop diuretic, reduced by 30% the {sup 22}Na entry into dialysate. Microprobe dialysis of fluid in the cisterna magna is thus a minimally invasive and economical method for evaluating effects of drugs and hormones on the choroid plexus-CSF system.

• OSTI ID: 5733455
• Journal Information: Journal of Neurosurgery; (USA), Vol. 74:6; ISSN 0022-3085
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CEREBROSPINAL FLUID
DIALYSIS
SODIUM COMPOUNDS
MEMBRANE TRANSPORT
RATS
SODIUM 22
TRACER TECHNIQUES
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BODY FLUIDS
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MAMMALS
MATERIALS
NANOSEC LIVING RADIOISOTOPES
NUCLEI
ODD-ODD NUCLEI
RADIOISOTOPES
RODENTS
SEPARATION PROCESSES
SODIUM ISOTOPES
VERTEBRATES
YEARS LIVING RADIOISOTOPES
550201* - Biochemistry- Tracer Techniques