Molecular heterogeneity and alternative splicing of human lactoperoxidase.

Human lactoperoxidase (LPO) exists as two distinct molecules independent of glycosylation. The N-terminus of one form is blocked and has not been identified while the other is proteolytically processed at the N-terminus similar to myeloperoxidase. Our analysis identified alternatively spliced human LPO mRNAs that may explain the observed molecular heterogeneity of LPO.

Norepinephrine transport by the extraneuronal monoamine transporter in human bronchial arterial smooth muscle cells.

Inhaled glucocorticosteroids (GSs) cause acute, alpha1-adrenoreceptor (AR)-mediated bronchial vasoconstriction. After release from sympathetic nerves, norepinephrine (NE) must be taken up into cells for deactivation by intracellular enzymes. Because postsynaptic cellular NE uptake is steroid sensitive, GSs could increase NE concentrations at alpha1-AR, causing vasoconstriction.

Systemic ovalbumin sensitization downregulates norepinephrine uptake by rabbit aortic smooth muscle cells.

Norepinephrine (NE) concentration at alpha-adrenergic receptors is partially regulated by steroid-sensitive, extraneuronal catecholamine uptake (uptake-2). Because alpha(1)-adrenergic agonist- and glucocorticosteroid (GS)-induced bronchial vasoconstriction is enhanced in individuals with asthma, atopy could be associated with decreased uptake-2 by vascular smooth muscle cells (SMCs). We therefore evaluated whether NE uptake and its specific transporter messenger RNA (mRNA) were reduced in aortic SMCs of rabbits systemically sensitized with ovalbumin (OVA).