Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Nov 5:934:175255.
doi: 10.1016/j.ejphar.2022.175255. Epub 2022 Sep 9.

Dual effect of amitriptyline in the control of vascular tone: Direct blockade of calcium channel in smooth muscle cells and reduction of TLR4-dependent NO production in endothelial cells

Juliana Maria Navia-Pelaez  1 , Melissa Tainan Silva Dias  2 , Laura Alejandra Ariza Orellano  3 , Gianne Paul Campos  4 , Jacqueline Alvarez-Leite  5 , Paula Peixoto Campos  6 , Luciano Santos Aggum Capettini  7
Affiliations

Dual effect of amitriptyline in the control of vascular tone: Direct blockade of calcium channel in smooth muscle cells and reduction of TLR4-dependent NO production in endothelial cells

Juliana Maria Navia-Pelaez et al. Eur J Pharmacol. .

Abstract

Background and purpose: Amitriptyline (AM) is a classical and typical tricyclic antidepressant drug. Despite its well-known effects on the nervous system, it has been described to work as a TLR4 antagonist and several clinical works suggested some unexpected cardiovascular effects. The role of amitriptyline on vascular tone is not clear, thus we hypothesized that amitriptyline has a double effect on vascular tone by both endothelial TLR4-dependent nitric oxide down-regulation and calcium channel blockade in smooth muscle cells.

Experimental approach: Changes in isometric tension were recorded on a wire myograph. NO production was evaluated by fluorescence microscopy and flow cytometry in the mouse aorta and EAhy926 cells using DAF fluorescence intensity. Calcium influx was evaluated in A7r5 cells by flow cytometry. Western blot was used to analyze eNOS and nNOS phosphorylation.

Key results: AM reduced PE-induced contraction by calcium influx diminution in smooth muscle cells (F/F0 = 225.6 ± 15.9 and 118.6 ± 17.6 to CT and AM, respectively). AM impaired Ach-dependent vasodilation (Emax = 95.8 ± 1.4; 78.1 ± 1.8; 60.4 ± 2.9 and -7.4 ± 1.0 for CT, 0.01, 0,1 and 1 μmol/L AM, respectively) through reduction of calcium influx and NO availability and TLR4 antagonism in a concentration-dependent manner. AM or TLR4 gene deletion significantly reduced NO production (Fluorescence = 9503 ± 871.7, 2561 ± 282, 4771 ± 728 and 1029 ± 103 to CT, AM, TLR4-/- and AM + TLR4-/-, respectively) by an increase in nNOSser852 and reduction in eNOSser1177 phosphorylation in endothelial cells.

Conclusions and implications: Our data show that amitriptyline impaired vascular function through two different mechanisms: blockade of TLR4 in endothelial cells and consequent decrease in NO production and calcium influx reduction in smooth muscle and endothelial cells. We also suggest, for the first time, nNOS activity reduction by AM in non-neuronal cells.

Keywords: Amitriptyline; Calcium channels; Nitric oxide; TLR4; Vascular tone.

PubMed Disclaimer

Conflict of interest statement

Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.