On the functions of astrocyte-mediated neuronal slow inward currents

Slow inward currents are known as neuronal excitatory currents mediated by glutamate release and activation of neuronal extra synaptic N-met hyl-D-aspartate receptors with the contribution of astrocytes.These events are significantly slower than the excitatory postsynaptic currents.Parameters of slow inward currents are determined by seve ral factors including the mechanisms of astrocytic activation and glutamate release,as well as the diffusion pathways from the release site towards the extra synaptic recepto rs.Astrocytes are stimulated by neuronal network activity,which in turn excite neurons,forming an astrocyte-neuron feedback loop.Mostly as a consequence of brain edema,astrocytic swelling can also induce slow inward currents under pathological conditions.There is a growing body of evidence on the roles of slow inward currents on a single neuron or local network level.These events often occur in synchro ny on neurons located in the same astrocytic domain.Besides synchronization of neuronal excitability,slow inward currents also set synaptic strength via eliciting timing-dependent synaptic plasticity.In addition,slow inward currents are also subject to non-synaptic plasticity triggered by long-la sting stimulation of the excitatory inputs.Of note,there might be important regionspecific differences in the roles and actions triggering slow inward currents.In greater networks,the pathophysiological roles of slow inward currents can be better understood than physiological ones.Slow inward currents are identified in the pathophysiological background of autism,as slow inward currents drive early hypersynchrony of the neural networks.Slow inward currents are significant contributors to paroxysmal depolarizational shifts/interictal spikes.These events are related to epilepsy,but also found in Alzheimer's disease,Parkinson's disease,and stroke,leading to the decline of cognitive functions.Events with features overlapping with slow inward currents(excitatory,N-methyl-Daspartate-receptor mediated currents with astrocytic contribution) as ischemic currents and spreading depolarization also have a well-known pathophysiological role in worsening consequences of stroke,traumatic brain injury,or epilepsy.One might assume that slow inward currents occurring with low frequency under physiological conditions might contribute to synaptic plasticity and memory formation.However,to state this,more experimental evidence from greater neuronal networks or the level of the individual is needed.In this review,I aimed to summarize findings on slow inward currents and to speculate on the potential functions of it.

Gabapentinoids for the treatment of stroke

Gabapentinoid drugs(pregabalin and gabapentin) have been successfully used in the treatment of neuro pathic pain and in focal seizure prevention.Recent research has demonstrated their potent activities in modulating neurotransmitter release in neuronal tissue,oxidative stress,and inflammation,which matches the mechanism of action via voltage-gated calcium channels.In this review,we briefly elaborate on the medicinal history and ligand-binding sites of gabapentinoids.We systematically summarize the preclinical and clinical research on gabapentinoids in stroke,including ischemic stro ke,intracerebral hemorrhage,subarachnoid hemorrhage,seizures after stro ke,cortical spreading depolarization after stroke,pain after stroke,and nerve regeneration after stro ke.This review also discusses the potential to rgets of gabapentinoids in stroke;however,the existing results are still unce rtain regarding the effect of gabapentinoids on stroke and related diseases.Further preclinical and clinical trials are needed to test the therapeutic potential of gabapentinoids in stroke.Therefore,gabapentinoids have both opportunities and challenges in the treatment of stroke.