Calcium diffusion through perineurium of frog sciatic nerve

Journal Article · Fri Jan 01 04:00:00 EST 1988 · American Journal of Physiology; (USA)

OSTI ID:7190452

Wadhwani, K C; Levitan, H; Rapoport, S I ^[1]

---

1. National Institutes of Health, Bethesda, MD (USA) Univ. of Maryland, College Park (USA)

Calcium and sucrose permeabilities (P{sub Ca} or P{sub sucrose}) were calculated from the fluxes of {sup 45}Ca and ({sup 3}H)sucrose across perfused everted and normal configurations of the perineurial cylinder isolated from the frog sciatic nerve and from fluxes into an intact nerve segment bathed in Ringer. Mean P{sub Ca} for influx across the isolated perineurium equaled 10.2 {plus minus} 0.6 {times} 10{sup {minus}7} cm/s compared with P{sub sucrose} = 7.4 {plus minus} 0.4 {times} 10{sup {minus}7} cm/s. For efflux, P{sub Ca} = 27.5 {plus minus} 5.0 x 10{sup {minus}7} cm/s and P{sub sucrose} = 23.2 {plus minus} 4.7 {times} 10{sup {minus}7} cm/s. The mean ratio of P{sub Ca} for efflux to P{sub Ca} for influx was not significantly different from the flux ratio for sucrose. Asymmetrical fluxes across the perineurial cylinder were due presumably to bulk flow and resultant solvent drag out of the lumen caused by perfusion pressure. Calcium accumulated in the perineurial tissue in a saturable manner with a K{sub m} of 80 {mu}M and a B{sub max} of 0.22 {mu}mol/g wet wt. The half time for calcium exchange from the external medium to the nerve was calculated as 3 h. This long half time and the calcium-sequestering ability of the perineurium suggest that the perineurium can stabilize endoneurial calcium during transient changes in the calcium concentration of plasma.

• OSTI ID: 7190452
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 254:1; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
AMPHIBIANS
ANIMALS
AQUATIC ORGANISMS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CALCIUM 45
CALCIUM CHLORIDES
CALCIUM COMPOUNDS
CALCIUM HALIDES
CALCIUM ISOTOPES
CARBOHYDRATES
CHLORIDES
CHLORINE COMPOUNDS
DAYS LIVING RADIOISOTOPES
DISACCHARIDES
EVEN-ODD NUCLEI
FROGS
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
INTERMEDIATE MASS NUCLEI
ISOTOPES
KINETICS
MEMBRANE TRANSPORT
NERVES
NERVOUS SYSTEM
NUCLEI
OLIGOSACCHARIDES
ORGANIC COMPOUNDS
PERMEABILITY
PHYSIOLOGY
RADIOISOTOPES
REACTION KINETICS
SACCHARIDES
SACCHAROSE
SCIATIC NERVE
TRITIUM COMPOUNDS
UPTAKE
VERTEBRATES