Modulation of cerebral vascular tone by activated glia: involvement of nitric oxide.
The ability of activated glia to affect cerebral vascular tone has been evaluated using an in vitro experimental system in which basilar arteries were incubated with glial cultures activated by treatment with lipopolysaccharide (LPS). Vascular tone was measured with an isometric myograph. Contraction in response to high KCl and serotonin was reduced in arteries co-incubated for 24 h with LPS-activated glia, whereas the response to acetylcholine was not modified. The reduced contraction was prevented when the nitric oxide synthase (NOS) inhibitor L-N-nitro-arginine (L-NNA) was added throughout the whole incubation time (activation of glial cells with LPS + co-incubation of glial cells with cerebral arteries). Under these conditions, nitrite levels were drastically reduced. A reduced contraction to KCl was also observed after treatment of the cerebral vessel with sodium nitroprusside. In contrast, L-NNA added to the vessel did not modify the response to contracting stimuli and the expression of endothelial NOS was not modified in cerebral arteries pre-incubated with activated glia. These results suggest that activated glia, which finds an in vivo correlate in several neuropathological conditions, can contribute to changes of vascular tone by modifying the levels of nitric oxide (NO) to which the vessel is exposed.
Chisari
M
M
Department of Experimental and Clinical Pharmacology, University of Catania, Italy.
Salomone
S
S
Laureanti
F
F
Copani
A
A
Sortino
M A
MA
D000109:Acetylcholine / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000502:physiology*; D001488:Basilar Artery / Q000187:drug effects / Q000502:physiology*; D015153:Blotting, Western / Q000379:methods; D020126:Brefeldin A / Q000494:pharmacology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000098:blood supply* / Q000166:cytology; D018920:Coculture Techniques / Q000379:methods; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D016207:Cytokines / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007150:Immunohistochemistry / Q000379:methods; D007537:Isometric Contraction / Q000187:drug effects / Q000502:physiology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D009213:Myography / Q000379:methods; D009457:Neuroglia / Q000502:physiology*; D009566:Nitrates / Q000378:metabolism; D009569:Nitric Oxide / Q000502:physiology*; D009573:Nitrites / Q000378:metabolism; D019335:Nitroarginine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000494:pharmacology; D013997:Time Factors
D016895:Culture Media, Serum-Free; D016207:Cytokines; D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D009566:Nitrates; D009573:Nitrites; D020126:Brefeldin A; D019335:Nitroarginine; D009569:Nitric Oxide; D012701:Serotonin; D011189:Potassium Chloride; D000109:Acetylcholine