Noradrenergic agonists and antagonists influence migration of cortical spreading depression in rat - A possible mechanism of migraine prophylaxis and prevention of postischemic neuronal damage

Abstract

Cortical spreading depression (CSD) is thought to be a neuronal mechanism that expands the penumbra zone after focal brain ischemia and that causes migraine aura. Both adrenergic agonists and antagonists significantly influence the size of the penumbra zone and decline the frequency of migraine. To study whether these compounds act by influencing CSD, we applied different drugs topically to an area of the exposed cortex of anesthetized adult rats and observed the migration of CSD-related DC potential deflections across the treated area. The adrenergic agonist norepinephrine (1 mmol/L) and the α2-agonist clonidine (0.56 mmol/L) blocked reversibly the migration of CSD. The β-blocker propranolol (250 μmol/L to 1 mmol/L) dose-dependently diminished migration velocity or even blocked migration of CSD. The CSD blockade by the α2-antagonist yohimbine (1.75 mmol/L) was because of its action on inhibitory 5-HT1A receptors. None of the substances in the concentrations used had influence on regional cerebral blood flow or on systemic arterial blood pressure. The data suggest that the interference of these compounds with CSD may contribute to their beneficial therapeutic effect. The effect of β-receptor antagonists in human migraine needs further exploration, since these drugs also work in migraine without aura. © 2005 ISCBFM All rights reserved.