ISSN:
1471-4159
Quelle:
Blackwell Publishing Journal Backfiles 1879-2005
Thema:
Medizin
Notizen:
Abstract: The effects of short- and long-chain fatty acids on the cerebromicrovascular (Na++ K+)-ATPase were investigated using specific [3H]ouabain binding to the enzyme. Specific binding increased linearly with total microvessel protein (37–110 μg) and was time-dependent with maximum binding obtained by 10 min. Arachidonic acid, but not palmitic acid, stimulated [3H]ouabain binding in a dose-dependent manner, with a 105% increase over basal levels at 100 μM arachidonic acid. Preincubation of the microvessels with arachidonic acid did not alter the stimulation observed. 4-Pentenoic acid stimulated [3H]ouabain binding only at high concentrations (10 mM). Scatchard analysis of [3H]ouabain binding to untreated microvessels yielded a single class of “high-affinity” binding sites with an apparent binding affinity (KD) of 64.7 ± 2.0 nM and a binding capacity (Bmax) of 10.1 ± 1.5 pmol/mg protein. In the presence of 100 μM arachidonic acid, a monophasic Scatchard plot also was obtained, but the KD significantly decreased to 51.9 ± 2.7 nM (p 〈 0.01), whereas the Bmax remained virtually unchanged (12.5 ± 1.2 pmol/mg protein). The stimulation of [3H]ouabain binding in the presence of arachidonic acid was potentiated by 4-pentenoic acid, but not by indomethacin or eicosatetraynoic acid. These data suggest that long-chain polyunsaturated fatty acids may be involved in the regulation of blood-brain barrier (Na++ K+)-ATPase and may play a role in the cerebral dysfunction associated with diseases in which plasma levels of nonesterified fatty acids are elevated.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1111/j.1471-4159.1988.tb10595.x
