Document Detail


Cholinergic neurogenic vasodilatation is mediated by nitric oxide in the dog hindlimb.
MedLine Citation:
PMID:  8181044     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: The aim was to investigate the role of nitric oxide (NO) in cholinergic neurogenic vasodilatation in the dog hindlimb using the NO synthase inhibitor, N-nitro-L-arginine (NOLA), and the NO precursor, L-arginine. METHODS: 20 dogs were anaesthetised with thiopentone and alpha chloralose and experiments were performed in the presence of noradrenergic neurone blockade with guanethidine (15 mg.kg-1 subcutaneously). Using stereotaxic procedures, specific sites in the hypothalamus were electrically stimulated (HS) to produce depressor and hindlimb vasodilator responses. In each experiment, responses to intra-arterial (ia) injections of acetylcholine and glyceryl trinitrate produced increases in femoral blood flow similar to those caused by HS. RESULTS: Vasodilator responses to HS and acetylcholine but not glyceryl trinitrate were reduced by the muscarinic receptor antagonists tropicamide (3-12 mg ia) or atropine (0.5 mg.kg-1 intravenously, i.v.). Administration of NOLA (5-15 mg.kg-1 ia) significantly attenuated the HS induced decrease in arterial pressure [delta AP: control = -21 (SEM 3) mm Hg v NOLA treated = -9(3) mm Hg, p < 0.005] and the increase in femoral blood flow [delta FBF: control = 43(7) ml.min-1 v NOLA treated = 17(4) ml.min-1, p < 0.005]. NOLA also significantly inhibited femoral vasodilator responses to acetylcholine [delta FBF: control = 47(6) ml.min-1 v NOLA treated = 35(6) ml.min-1, p < 0.05] whereas responses to glyceryl trinitrate were enhanced [delta FBF: control = 54(9) ml.min-1 v NOLA treated = 69(9) ml.min-1, p < 0.005]. In addition L-arginine (150-300 mg.kg-1 i.v.), but not D-arginine (150 mg.kg-1 i.v.), reversed the inhibitory effect of NOLA on HS induced dilator responses [delta FBF: NOLA treated = 14(4) ml.min-1 v L-arginine treated = 35(8) ml.min-1, n = 8; greater than NOLA treated, p < 0.05]. CONCLUSIONS: Vasodilatation in the dog hindlimb evoked by activation of cholinergic nerves involves the synthesis of NO; however the source of this NO remains to be determined.
Authors:
K E Loke; C G Sobey; G J Dusting; O L Woodman
Related Documents :
8969734 - Effect of methylene blue on refractory neonatal hypotension.
11116104 - Transient hypertension directly impairs endothelium-dependent vasodilation of the human...
7509294 - Attenuation of chronic hypoxic pulmonary hypertension in rats by cyclooxygenase product...
11085964 - Impairment of endothelium-dependent vasodilation of resistance vessels in patients with...
9228874 - Asymmetry of gait initiation in hemiparetic stroke subjects.
24608494 - Effects of synchronized intermittent mandatory ventilation versus pressure support plus...
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Cardiovascular research     Volume:  28     ISSN:  0008-6363     ISO Abbreviation:  Cardiovasc. Res.     Publication Date:  1994 Apr 
Date Detail:
Created Date:  1994-06-10     Completed Date:  1994-06-10     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0077427     Medline TA:  Cardiovasc Res     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  542-7     Citation Subset:  IM    
Affiliation:
Department of Pharmacology, University of Melbourne, Parkville, Victoria, Australia.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Acetylcholine / pharmacology
Animals
Arginine / analogs & derivatives,  pharmacology
Atropine / pharmacology
Cholinergic Fibers / physiology*
Dogs
Electric Stimulation
Female
Hindlimb
Hypothalamus / physiology
Male
Nitric Oxide / physiology*
Nitroarginine
Nitroglycerin / pharmacology
Tropicamide / pharmacology
Vasodilation / drug effects,  physiology*
Chemical
Reg. No./Substance:
10102-43-9/Nitric Oxide; 1508-75-4/Tropicamide; 2149-70-4/Nitroarginine; 51-55-8/Atropine; 51-84-3/Acetylcholine; 55-63-0/Nitroglycerin; 74-79-3/Arginine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Previous beat contraction history alters mechanical restitution in the isolated left ventricle.
Next Document:  Depressed transient outward and calcium currents in dilated human atria.