title: Release of immunoreactive angiotensin II from neuronal cultures: adrenergic influences.
abstract: The effects of adrenergic drugs on the release of immunoreactive angiotensin II (ANG II-ir) from brain cells in culture were examined. In neuronal cultures, basal release of Ang II-ir was 43.65 +/- 7.44 pg/5-min incubation period (n = 14 experiments; 52 individual determinations), and in astrocytic glial cultures, it was 21.76 +/- 5.7 pg (n = 8 experiments; 24 individual determinations) when cells were exposed to buffer alone. Incubation of neuronal cultures with the alpha 2-adrenergic antagonist yohimbine (0.1-50 microM, 5 min) caused concentration-dependent increases in ANG II-ir release above basal levels. Analysis of the released material by high-pressure liquid chromatography revealed that authentic ANG II was present. No increase in the release of ANG II-ir was seen from glial cells. Experiments using neuronal cultures revealed that the yohimbine-induced release of ANG II-ir may be secondary to increased norepinephrine (NE) release. Incubation of neuronal cultures with NE (10 nM-50 microM) caused concentration-dependent increases in the release of ANG II-ir. This effect of NE was not inhibited by the alpha 1-adrenergic blocker prazosin. However, a weaker release of ANG II-ir from neuronal cultures was stimulated by the beta-adrenergic agonist isoproterenol at 100 microM. These data show that ANG II-ir can be released from neuronal but not glial cell cultures by adrenergic receptor-mediated mechanisms.
authors.affiliation: Department of Physiology, College of Medicine, University of Florida, Gainesville 32610.
authors.forename: E M
authors.initials: EM
authors.lastname: Richards
authors.forename: K
authors.initials: K
authors.lastname: Hermann
authors.forename: C
authors.initials: C
authors.lastname: Sumners
authors.forename: M K
authors.initials: MK
authors.lastname: Raizada
authors.forename: M I
authors.initials: MI
authors.lastname: Phillips
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000804:Angiotensin II / Q000276:immunology / Q000378:metabolism*; D000818:Animals; D002395:Catecholamines / Q000494:pharmacology; D002478:Cells, Cultured; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D002395:Catecholamines; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D000804:Angiotensin II; D015016:Yohimbine; D009638:Norepinephrine