title: Chronically lowering sympathetic activity protects sympathetic nerves in spleens from aging F344 rats.
abstract: In the present study, we investigated how increased sympathetic tone during middle-age affects the splenic sympathetic neurotransmission. Fifteen-month-old (M) F344 rats received rilmenidine (0, 0.5 or 1.5mg/kg/day, i.p. for 90 days) to lower sympathetic tone. Controls for age were untreated 3 or 18M rats. We report that rilmenidine (1) reduced plasma and splenic norepinephrine concentrations and splenic norepinephrine turnover, and partially reversed the sympathetic nerve loss; and (2) increased β-adrenergic receptor (β-AR) density and β-AR-stimulated cAMP production. Collectively, these findings suggest a protective effect of lowering sympathetic tone on sympathetic nerve integrity, and enhanced sympathetic neurotransmission in secondary immune organs.
authors.affiliation: Department of Physiology & Pharmacology, Loma Linda University, School of Medicine, Loma Linda, CA 92350, USA.
authors.forename: Sam D
authors.initials: SD
authors.lastname: Perez
authors.forename: Brooke
authors.initials: B
authors.lastname: Kozic
authors.forename: Christine A
authors.initials: CA
authors.lastname: Molinaro
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Thyagarajan
authors.forename: Mark
authors.initials: M
authors.lastname: Ghamsary
authors.forename: Cheri L
authors.initials: CL
authors.lastname: Lubahn
authors.forename: Dianne
authors.initials: D
authors.lastname: Lorton
authors.forename: Denise L
authors.initials: DL
authors.lastname: Bellinger
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000493:pharmacokinetics; D000375:Aging; D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002395:Catecholamines / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D008297:Male; D009638:Norepinephrine / Q000378:metabolism*; D009929:Organ Size / Q000187:drug effects; D010080:Oxazoles / Q000494:pharmacology; D011412:Propanolamines / Q000493:pharmacokinetics; D011485:Protein Binding / Q000187:drug effects; D011897:Random Allocation; D051381:Rats; D011916:Rats, Inbred F344; D017207:Rats, Sprague-Dawley; D011943:Receptors, Adrenergic, beta / Q000378:metabolism; D000077769:Rilmenidine; D013154:Spleen / Q000166:cytology / Q000294:innervation* / Q000378:metabolism; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000502:physiology*; D013997:Time Factors
chemical_list: D000316:Adrenergic alpha-Agonists; D000318:Adrenergic beta-Agonists; D002395:Catecholamines; D010080:Oxazoles; D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; D000242:Cyclic AMP; D000077769:Rilmenidine; C033394:CGP 12177; D009638:Norepinephrine