Abstract

The neuromuscular junction (NMJ) is a critical cholinergic synapse where acetylcholine (ACh) release is tightly regulated by various mechanisms, including purinergic signaling. This study investigates the role of the plasma membrane channel Pannexin 1 (Panx1) in the purinergic modulation of ACh release at mouse motor synapses. The research objective was to compare the changes in purinergic regulation under conditions of pharmacological blockade of Panx1 with its genetic knockout. Using electrophysiological techniques on isolated mouse nerve-muscle preparations, we measured spontaneous and evoked ACh release. Pharmacological inhibition of Panx1 with probenecid or carbenoxolone, as well as genetic deletion of the Panx1 gene, significantly altered the sensitivity of the synapse to purinergic agonists and antagonists. Specifically, the regulatory effect of P2 receptors on miniature endplate potential frequency was diminished in both the blocked and knockout conditions, suggesting that Panx1-mediated ATP release is a key component of the presynaptic purinergic feedback loop. These findings highlight Panx1 as an essential membrane protein in the homeostatic control of neurotransmitter release at the NMJ.