Document Detail

Crosstalk between central pathways of nitric oxide and carbon monoxide in the hypertensive action of cyclosporine.
MedLine Citation:
PMID:  22226938     Owner:  NLM     Status:  Publisher    
Although the intermediary role of central neurons in the hypertensive and sympathoexcitatory actions of cyclosporine (CSA) has been recognized in previous studies including our own, the underlying mechanism remains obscure. In this study, we tested the hypothesis that central pathways of nitric oxide (NO) and carbon monoxide (CO) modulate the blood pressure (BP) response elicited by CSA in conscious rats. Hemodynamic effects of CSA were evaluated in absence and presence of maneuvers that inhibit or facilitate biosynthesizing enzymes of NO (NOS) or CO (heme oxygenase, HO). CSA (20mg/kg i.v.) produced abrupt increases in BP that peaked in 5min and maintained for at least 45min. The hypertensive effect of CSA disappeared in rats pretreated intracisternally (i.c.) with N(ω)-nitro-l-arginine methyl ester (L-NAME, nonselective NOS inhibitor), N(5)-(1-iminoethyl)-l-ornithine (L-NIO, selective eNOS inhibitor), N(ω)-propyl-l-arginine (NPLA, selective nNOS inhibitor), or 1H-[1,2,4] oxadiazolo[4,3-a] quinoxalin-1-one (ODQ, guanylate cyclase inhibitor), suggesting the importance of central eNOS/nNOS/GC cascade in CSA-induced hypertension. L-NAME also abolished the hypotension caused by the sympatholytic drug moxonidine, indicating a tonic sympathoinhibitory action for NO. The inhibition of HO activity by zinc protoporphyrin IX (ZnPP) abrogated the hypertensive action of CSA. The abolition by L-NAME or ZnPP of CSA hypertension was compromised upon simultaneous i.c. exposure to hemin (HO substrate) and l-arginine (NOS substrate), respectively. Together, the interruption of the mutually facilitated NOS/NO and HO/CO pathways and coupled GC/cGMP in central neuronal pools accounts, at least partly, for the hypertensive and perhaps sympathoexcitatory actions of CSA.
Mahmoud M El-Mas; Amal G Omar; Mai M Helmy; Mahmoud M Mohy El-Din
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-12-29
Journal Detail:
Title:  Neuropharmacology     Volume:  -     ISSN:  1873-7064     ISO Abbreviation:  -     Publication Date:  2011 Dec 
Date Detail:
Created Date:  2012-1-9     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0236217     Medline TA:  Neuropharmacology     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2011 Elsevier Ltd. All rights reserved.
Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Champlion Street, Alexandria 21521, Egypt.
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