GsMTx4 is a spider venom peptide that selectively inhibits cationic-permeable mechanosensitive channels (MSCs) belonging to the Piezo and TRP channel families. GsMTx4 also blocks cation-selective stretch-activated channels (SACs) , attenuates lysophosphatidylcholine (LPC)-induced astrocyte toxicity and microglial reactivity. GsMTx4 is an important pharmacological tool for identifying the role of these excitatory MSCs in normal physiology and pathology.