Cholinergic modulation inhibits cortical spreading depression in mouse neocortex through activation of muscarinic receptors and decreased excitatory/inhibitory drive

Abstract

Cortical spreading depression (CSD) is a wave of transient network hyperexcitability leading to long lasting depolarization and block of firing, which initiates focally and slowly propagates in the cerebral cortex. It causes migraine aura and it has been implicated in the generation of migraine headache. Cortical excitability can be modulated by cholinergic actions, leading in neocortical slices to the generation of rhythmic synchronous activities (UP/DOWN states). We investigated the effect of cholinergic activation with the cholinomimetic agonist carbachol on CSD triggered with 130mM KCl pulse injections in acute mouse neocortical brain slices, hypothesizing that the cholinergic-induced increase of cortical network excitability during UP states could facilitate CSD. We observed instead an inhibitory effect of cholinergic activation on both initiation and propagation of CSD, through the action of muscarinic receptors. In fact, carbachol-induced CSD inhibition was blocked by atropine or by the preferential M1 muscarinic antagonist telenzepine; the preferential M1 muscarinic agonist McN-A-343 inhibited CSD similarly to carbachol, and its effect was blocked by telenzepine. Recordings of spontaneous excitatory and inhibitory post-synaptic currents in pyramidal neurons showed that McN-A-343 induced overall a decrease of the excitatory/inhibitory ratio. This inhibitory action may be targeted for novel pharmacological approaches in the treatment of migraine with muscarinic agonists.

GABAergic neurons and NaV1.1 channel hyperactivity: a novel neocortex-specific mechanism of Cortical Spreading Depression

“…1b1-b2 & d). To confirm that this was a neocortex-specific effect of Hm1a, we evaluated if in our conditions other brain areas were able to generate spreading depression by applying short puffs of 130mM KCl, a classic method of CSD induction (Pietrobon and Moskowitz, 2014;Zerimech et al, 2020). The success rate for CSD induction was 100% in all the structures tested: the neocortex ( Supplementary Fig.S2a-c), the striatum ( Supplementary Fig.S2d1) and the hippocampus ( Supplementary Fig.S2d2).…”

“…Brain slices were prepared as previously described (Hedrich et al, 2014;Zerimech et al, 2020). Briefly, mice were killed by decapitation under isoflurane anesthesia, the brain was quickly removed and placed in ice-cold artificial cerebrospinal fluid (ACSF), which contained (in mM): 125 NaCl, 2.5 KCl, 2 CaCl2, 1 MgCl2, 1.25 NaH2PO4, 25 NaHCO3 and 25 glucose, saturated with 95 % O2 -5 % CO2.…”

“…Cortical spreading depression was induced by brief puffs of KCl (130 mM) in the superficial cortical layers (layers 1-3) with a glass micropipette (2-4 MΩ) connected to an air pressure injector (holding pressure: < 1 PSI, injection pressure: 7 to 10 PSI; PV820 Pneumatic Picopump, WPI, USA) (Zerimech et al, 2020). The field potential recording pipette was placed at least 500 μm away from the CSD induction area.…”

Rescuing epileptic and behavioral alterations in a Dravet syndrome mouse model by inhibiting eukaryotic eEF2K

“…Hippocampal slices were prepared from P25–P35 mice using standard procedures (Liautard et al, 2013; Zerimech et al, 2020). Mice were deeply anesthetized with isoflurane and decapitated.…”

Migraine and Two-Pore-Domain Potassium Channels

“…Early studies on the genetics of migraine have led to the identification of several genes responsible for rare cases of familial hemiplegic migraine (FHM). This includes FHM1, a gain-of-function mutation affecting the alpha subunit of the voltage-gated calcium channel Ca v 2.1 (CACNA1A) leading to an increase in synaptic transmission (van den Maagdenberg and others 2004), FHM2, a loss-of-function mutation targeting the alpha 2 subunit of the astrocytic Na + /K + ATP-dependent pump (ATP1A2) and resulting in an impaired clearance of synaptic glutamate (De Fusco and others 2003) and FHM3, impairing the alpha subunit of the voltage-gated sodium channel Na v 1.1 (SCN1A) (Dichgans and others 2005; Zerimech and others 2020). However, those mutations are also linked to other diseases such as dyskinesia, ataxia, or mental retardation.…”