title: Release of prostaglandin E2 from brain of cat: II. In vivo studies on the effects of adrenergic, cholinergic and dopaminergic agonists and antagonists.
abstract: This study examined the effect of several neurotransmitters, receptor agonists and antagonists on the release of prostaglandin E2 (PGE2) from brain. Levels of PGE2 were measured in consecutive 30-min samples, collected from ventriculocisternal perfusions (100 microliters/min) in chloralose-urethanized cats, before, during and after the addition of carbachol, norepinephrine (NE) and dopamine (DA). Samples were submitted to acid organic extraction and radioimmunoassay (RIA) with a specific antibody. Displacement curves of ligand binding with control and stimulated samples were parallel to those observed with PGE2. The addition of carbachol (10(-4) M) to the perfusate resulted in a significant increase in the levels of PGE2 from 600 +/- 259 pg PGE2/min during the control period up to 1306 +/- 429 pg PGE2/min during the perfusion (P less than 0.02). Though NE (10(-3) M) and isoproterenol (10(-3) M, beta) were without effect, methoxamine (10(-3) M, alpha 1), but not ST-91 (an alpha 2-agonist), produced an increase in secretion of PGE2. This increase was blocked by phentolamine (10(-3) M). The addition of DA (10(-4) M) produced a fall from control levels of 642 +/- 185 pg PGE2/min to 290 +/- 101 pg PGE2/min (P less than 0.02). These results suggest that the central activation of selected populations of receptors will alter basal levels of PGE2 in the extracellular space.
authors.affiliation: Section of Neurosurgical Research, Mayo Clinic, Rochester, Minnesota 55905.
authors.forename: E
authors.initials: E
authors.lastname: Navarro
authors.forename: S D
authors.initials: SD
authors.lastname: Romero
authors.forename: T L
authors.initials: TL
authors.lastname: Yaksh
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002415:Cats; D015232:Dinoprostone / Q000378:metabolism*; D011950:Receptors, Cholinergic / Q000187:drug effects*; D011954:Receptors, Dopamine / Q000187:drug effects*
chemical_list: D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D011950:Receptors, Cholinergic; D011954:Receptors, Dopamine; D015232:Dinoprostone