title: Regulation of interleukin-6 (IL-6) secretion in primary cultured rat astrocytes: synergism of interleukin-1 (IL-1) and pituitary adenylate cyclase activating polypeptide (PACAP).
abstract: Interleukin-6 (IL-6) is a pleiotropic cytokine that is produced by astrocytes and microglia and may act as a trophic factor in the nervous system. These experiments were intended to identify neuroactive agents that regulate IL-6 production in primary cultured rat astrocytes. Addition of either lipopolysaccharide (LPS) or human recombinant interleukin-1 beta (IL-1 beta) to rat astrocytes in culture stimulated IL-6 secretion. However, LPS was significantly more efficacious in eliciting IL-6 production compared to IL-1 beta. Co-addition of the specific IL-1 receptor antagonist (IL-1ra) completely inhibited IL-1 beta-induced IL-6 secretion but did not affect LPS-stimulated IL-6 production during a 6 h incubation period. Two neuroactive peptides, pituitary adenylate cyclase activating polypeptide (PACAP38) and vasoactive intestinal peptide (VIP), stimulated IL-6 production either alone or in combination with IL-1 beta. PACAP38 was significantly more potent in stimulating IL-6 compared to VIP. Results from these experiments indicate that LPS is an effective inducer of IL-6 production in rat astrocytes. This effect of LPS is independent of astrocyte IL-1 production since the IL-1ra was unable to inhibit LPS-stimulated IL-6 secretion. Also, the neuropeptides PACAP38 and VIP are potential secretagogues for IL-6 secretion, and both peptides synergize with IL-1 to stimulate IL-6 secretion in rat astrocytes.
authors.affiliation: University of South Florida College of Medicine, Department of Pharmacology and Therapeutics, Tampa 33612-4799.
authors.forename: P E
authors.initials: PE
authors.lastname: Gottschall
authors.forename: I
authors.initials: I
authors.lastname: Tatsuno
authors.forename: A
authors.initials: A
authors.lastname: Arimura
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004357:Drug Synergism; D006825:Hybridomas / Q000187:drug effects / Q000378:metabolism; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D015850:Interleukin-6 / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D009479:Neuropeptides / Q000494:pharmacology*; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051381:Rats; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
chemical_list: C495402:Adcyap1 protein, mouse; C495403:Adcyap1 protein, rat; D007375:Interleukin-1; D015850:Interleukin-6; D008070:Lipopolysaccharides; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D017472:Receptors, Interleukin-1; D014660:Vasoactive Intestinal Peptide; D000262:Adenylyl Cyclases