These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Cerebroarterial relaxations mediated by nitric oxide derived from endothelium and vasodilator nerve.
    Author: Toda N, Ayajiki K, Okamura T.
    Journal: J Vasc Res; 1993; 30(2):61-7. PubMed ID: 7684937.
    Abstract:
    Purposes of this study were to determine whether: (1) nitric oxide is involved in endothelium-dependent relaxation in helical strips of dog cerebral arteries; (2) relaxing factor distinct from NO is also involved, and (3) susceptibility to NG-nitro-L-arginine (L-NA), an NO synthase inhibitor, of the response to mediators liberating NO from the endothelium and nerve differs. Changes in isometric tension were recorded. In the strips contracted with prostaglandin F2 alpha, substance P and arginine vasopressin produced a relaxation which was abolished or reversed to a contraction by endothelium denudation. The relaxations were not influenced by indomethacin but were suppressed dose-dependently by L-NA, as was the response to nicotine that stimulates the non-adrenergic, non-cholinergic vasodilator nerve and liberates NO. The inhibitions were reversed by L- but not D-arginine. NO (acidified NaNO2)-induced relaxations were not reduced by L-NA. The inhibitory effect was greater in the responses to vasopressin than substance P; however, there was no significant difference in the response to nicotine vs. the peptides. Substance P increased the level of cyclic guanosine monophosphate (GMP) in the artery strips with the intact endothelium, the effect being abolished by endothelium denudation, L-NA and oxyhemoglobin. Relaxations caused by adenosine triphosphate (ATP) and adenosine diphosphate (ADP) were dependent partially on the endothelium. Treatment with L-NA attenuated the ATP-induced relaxation in the strips with endothelium but did not alter the response of denuded strips.(ABSTRACT TRUNCATED AT 250 WORDS)
    [Abstract] [Full Text] [Related] [New Search]