Effects of garlic extract on spreading depression: In vitro and in vivo investigations

Abstract

Objectives: The potential use of garlic for prevention and treatment of different types of headaches has been suggested by several medieval literatures. Cortical spreading depression (CSD), a propagating wave of neuroglial depolarization, was established as a target for anti-migraine drugs. This study was designed to investigate the effect of garlic extract on CSD in adult rats.

Methods: CSD was induced by KCl microinjection in the somatosensory cortex. The effects of five different concentrations of garlic oil (1–500 μl/l) were tested on different characteristic features of CSD in necocortical slices. In in vivo experiments, the effects of garlic oil on electrophysiological and morphological changes induced by CSD were investigated.

Results: Garlic oil in a dose-dependent manner decreased the amplitude of CSD but not its duration and velocity in neocortical brain slices. Garlic oil at concentration of 500 μl/l reversibly reduced the amplitude of the field excitatory post-synaptic potentials and inhibited induction of long-term potentiation in the third layer of neocortical slices. In in vivo studies, systemic application of garlic oil (1 ml/l) for three consecutive days reduced the amplitude and repetition rate of CSD. Garlic oil also prevented of CSD-induced reactive astrocytosis in the neocortex.

Discussion: Garlic oil suppresses CSD, likely via inhibition of synaptic plasticity, and prevents its harmful effects on astrocyte. Further studies are required to identify the exact active ingredient(s) of garlic oil that inhibit CSD and may have the potential to use in treatment of CSD-related disorders.

Keywords:

• Cephalic pain
• Medicinal plants
• Traditional medicine
• Migraine
• Spreading depolarization

Acknowledgement

A part of this work was performed as doctoral thesis of C.M. in Münster University. This study (in vivo section) was supported by Shefa Neuroscience Research Center (Doctor Thesis 59880).

Disclaimer statements

Contributors Claudia Marschollek: Performed experiments in vitro and writing manuscript Fariba Karimzadeh, Maryam Jafarian and Milad Ahmadi: Performed experiments in vivo Seyed Mohammad Reza Mohajeri and Sadegh Rahimi: Developed software for mesurements, Analysis of data Erwin-Josef Speckmann: Supervised in vitro experiments, contributed in writing manuscript Ali Gorji: Supervisor of experiments, writing manuscript.

Funding None.

Conflicts of interest None.

Ethics approval Experiments were approved by Ethic Committee of Münster University and Shefa Neuroscience Center.