Modulatory Effects of Dopamine D2 Receptors on Spreading Depression in Rat Somatosensory Neocortex.
BACKGROUND
Spreading depression (SD) is a propagating wave of depolarization followed by depression of the neuroglial activities and can modulate extracellular dopamine concentrations in the neocortex. It has been shown that the dopaminergic system plays a role in migraine. SD has been suggested as a critical phenomenon in the pathophysiology of migraine. The aim of this study was to investigate the effect of dopamine D2 receptors on the characteristic features of SD in rat neocortical tissues.


METHODS
The effect of dopamine D2 receptor agonist quinpirole and D2 receptor antagonist sulpiride was tested on different characteristic features (amplitude, duration and velocity) of KCl-induced SD in somatosensory neocortical slices of adult rats. The effect of above-mentioned substances on production of long-term potentiation (LTP) in the neocortex was also evaluated.


RESULTS
The present data revealed a dose-dependent suppression of the amplitude and duration of SD in the presence of the dopamine D2 receptor antagonist sulpiride in the neocortex. D2 dopamine receptor agonist quinpirole dose-dependently enhanced the amplitude and duration of the neocortical SD. Furthermore, application of D2 receptor antagonist significantly suppressed induction of LTP.


CONCLUSIONS
These results indicate that D2 receptors modulate the initiation of SD in the neocortex. This finding refers to the potential role of D2 receptor antagonist in treatment of migraine pain.
Institute of Neurophysiology, Westfälische Wilhelms-Universität Münster, Germany.
Anna Maria
AM
Haarmann
Shefa Neuroscience Research Center, Tehran, Iran.; School of Advanced Medical Technology, Tehran University of Medical Sciences, Tehran, Iran.
Maryam
M
Jafarian
Shefa Neuroscience Research Center, Tehran, Iran.
Fariba
F
Karimzadeh
Shefa Neuroscience Research Center, Tehran, Iran.; Epilepsy Research Center, Westfälische Wilhelms-Universität Münster, Germany.
Ali
A
Gorji
In vitro; Migraine; Spreading depolarization; Stroke; Synapse