title: Central and peripheral changes in catecholamine biosynthesis and turnover in rats after a short period of ozone exposure.
abstract: We investigated in rat the effects of ozone exposure (0.7 ppm) for 5 h on the catecholamine biosynthesis and turnover in sympathetic efferents and various brain areas. For this purpose, the activity of tyrosine hydroxylase, the rate-limiting enzyme in catecholamine biosynthesis, was assessed in superior cervical ganglia and in two major noradrenergic cell groups, A2 and A6 (locus coeruleus). Tyrosine hydroxylase activity was estimated in vivo by measuring the accumulation of l-dihydroxyphenylalanine after pharmacological blockade of L-aromatic acid decarboxylases by NSD-1015 (100 mg/kg i.p.). The catecholamine turnover rate was measured after inhibition of tyrosine hydroxylase by alpha-methyl-para-tyrosine (AMPT, 250 mg/kg, i.p., 2.5 h) in peripheral sympathetic target organ (heart and lungs) as well as in some brain catecholamine terminal areas (cerebral cortex, hypothalamus and striatum). Ozone caused differential effects according to the structure. Catecholamine biosynthesis was stimulated in superior cervical ganglia (+44%, P < 0.05) and caudal A2 subset (+126%, P < 0.01), whereas catecholamine turnover was increased in heart (+183%, P < 0.01) and cortex (+22%, P < 0.05). On the other hand, catecholamine turnover was inhibited in lungs (-53%, P < 0.05) and striatum (-24%, P < 0.05). A brief exposure to ozone, at a concentration chosen to mimic pollution level encountered in urban areas, can modulate catecholamine biosynthesis and utilization rate in the sympathetic and central neurones.
authors.affiliation: Laboratoire de Physiologie Intégrative, Cellulaire et Moléculaire, UMR CNRS 5123, Bâtiment 404-Raphaël Dubois, Université Claude Bernard Lyon I, Campus de la Doua, 43 Boulevard du 11 Novembre 1918, F-69622 Villeurbanne Cedex, France. soulage@univ-lyon1.fr
authors.forename: Christophe
authors.initials: C
authors.lastname: Soulage
authors.forename: David
authors.initials: D
authors.lastname: Perrin
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Cottet-Emard
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Pequignot
authors.forename: Yvette
authors.initials: Y
authors.lastname: Dalmaz
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Pequignot
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D002395:Catecholamines / Q000096:biosynthesis*; D008168:Lung / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D010126:Ozone / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D002395:Catecholamines; D010126:Ozone