Buccalin is a neuropeptide that is colocalized with small cardioactive peptides in neuron B15. When applied exogenously at the ARC neuromuscular junction, Buccalin reduces the amplitude of muscle contractions triggered by motor neuron discharges, acting only presynaptically. It does not affect muscle relaxation rates and decreases excitatory junction potentials induced by motor neurons, without impacting contraction produced by acetylcholine acting directly on the muscle.