title: Reduced vascular beta-adrenergic receptors and catecholamine response in rats with lead induced hypertension.
abstract: Beta-adrenergic receptor-mediated relaxation of blood vessels declines in lead induced hypertension although the mechanism is unknown. We have utilized the aorta of lead hypertensive rats to investigate this problem. In an effort to elucidate the mechanism responsible for this alteration we examined plasma catecholamine levels, vascular beta-adrenergic receptor density, and cyclic adenosine monophosphate (cAMP) production in lead hypertensive rats. The density of beta-adrenergic receptors was 41% lower in the blood vessels of lead hypertensive rats compared with control rats. The corresponding apparent Kd values were not significantly different between two groups. The plasma catecholamine level was significantly higher in lead hypertensive rats compared with controls (P < 0.001). Stimulation of the vascular beta-adrenoceptor resulted in significantly lower levels of cAMP in lead hypertensive rats compared with controls (P < 0.001). The present results suggest that there is reduced beta-adrenoceptor density and diminished cAMP accumulation in blood vessels from lead hypertensive rats. Plasma catecholamine may play a role in the diminished beta-adrenoceptor and responsiveness to cAMP-mediated vascular relaxation in lead exposure.
authors.affiliation: Department of Cosmetic Science, Chia-Nan College of Pharmacy and Science, Tainan County, Taiwan.
authors.forename: H R
authors.initials: HR
authors.lastname: Chang
authors.forename: S S
authors.initials: SS
authors.lastname: Chen
authors.forename: D A
authors.initials: DA
authors.lastname: Tsao
authors.forename: J T
authors.initials: JT
authors.lastname: Cheng
authors.forename: C K
authors.initials: CK
authors.lastname: Ho
authors.forename: H S
authors.initials: HS
authors.lastname: Yu
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism; D002395:Catecholamines / Q000097:blood*; D000242:Cyclic AMP / Q000378:metabolism; D004837:Epinephrine / Q000097:blood; D006973:Hypertension / Q000139:chemically induced* / Q000378:metabolism; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D007854:Lead / Q000633:toxicity*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D009638:Norepinephrine / Q000097:blood; D009942:Organometallic Compounds / Q000097:blood / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000318:Adrenergic beta-Agonists; D002395:Catecholamines; D009942:Organometallic Compounds; D011943:Receptors, Adrenergic, beta; D007854:Lead; D000242:Cyclic AMP; D007545:Isoproterenol; C008261:lead acetate; D009638:Norepinephrine; D004837:Epinephrine