Reduction of lipopolysaccharide-induced neurotoxicity in mixed cortical neuron/glia cultures by femtomolar concentrations of pituitary adenylate cyclase-activating polypeptide.
Stimulation of murine primary mixed cortical neuron/glia cultures with lipopolysaccharide, an endotoxin, was used as a model for inflammatory disorders of the central nervous system. Lipopolysaccharide (20 microg/ml) increased the secretion of lactate dehydrogenase, a marker for cell injury, and nitric oxide into the culture medium. The lipopolysaccharide-induced release of lactate dehydrogenase into the culture medium was reduced by pituitary adenylate cyclase-activating polypeptide (PACAP) at 10(-14)-10(-12) M. The 27- and 38-amino-acid forms of PACAP were equipotent and their dose-response curves were U-shaped. PACAP6-38, a specific type I PACAP receptor antagonist, blocked the reduction by PACAP38 of the lipopolysaccharide-induced release of lactate dehydrogenase. The lipopolysaccharide-induced secretion of nitric oxide into the culture medium was reduced by PACAP at 10(-14)-10(-12) M and 10(-8)-10(-6) M. The 27- and 38-amino-acid forms of PACAP were equipotent. PACAP6-38 blocked the reduction of the lipopolysaccharide-induced secretion of nitric oxide by PACAP38 at 10(-12) M, but not at 10(-8) M. Vasoactive intestinal polypeptide reduced the lipopolysaccharide-induced release of lactate dehydrogenase into the culture medium at 10(-14)-10(-12) M, but these concentrations of vasoactive intestinal polypeptide had no effect on the lipopolysaccharide-induced secretion of nitric oxide. PACAP6-38 did not effect the reduction of the lipopolysaccharide-induced release of lactate dehydrogenase into the culture medium by 10(-12) M vasoactive intestinal polypeptide. These results indicate that stimulation of type I PACAP receptors by femtomolar concentrations of PACAP can prevent neuron death in a model for inflammatory disorders of the CNS. These results suggest that PACAP is also an extraordinarily potent inhibitor of some microglial functions.
Kong
L Y
LY
Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
Maderdrut
J L
JL
Jeohn
G H
GH
Hong
J S
JS
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology* / Q000502:physiology; D018920:Coculture Techniques; D004305:Dose-Response Relationship, Drug; D007770:L-Lactate Dehydrogenase; D008070:Lipopolysaccharides / Q000633:toxicity*; D051379:Mice; D009457:Neuroglia / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D009479:Neuropeptides / Q000494:pharmacology*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009498:Neurotoxins; D009573:Nitrites / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
C495402:Adcyap1 protein, mouse; D008070:Lipopolysaccharides; D009479:Neuropeptides; D018696:Neuroprotective Agents; D009498:Neurotoxins; D009573:Nitrites; D010446:Peptide Fragments; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D014409:Tumor Necrosis Factor-alpha; C075647:pituitary adenylate-cyclase-activating-peptide (6-38); D007770:L-Lactate Dehydrogenase