FMRF amide Molluscan Cardioexcitatory Peptide

Phe-Met-Arg-Phe (FMRF amide) is a neurotransmitter peptide which increases outward K+ currents and promotes dephosphorylation of many phosphoproteins in Aplysia sensory neurons. It is a cardioexcitatory substance from Macrocallista nimbosa (sun-ray clam), has physiological activities on the heart like augmenting, inducing and regularizing cardiac contraction.