G. Gaus et al., CARDIOINHIBITORY PEPTIDES FROM LIMULUS-POLYPHEMUS - MODULATION OF THENEUROGENIC HEART, Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology, 164(3), 1994, pp. 191-194
Four neuropeptides have been isolated and sequenced from acetone extra
cts of brains of the horseshoe crab Limulus polyphemus. They belong to
a newly discovered peptide family in invertebrates. A possible role o
f the four peptides from Limulus as cardioregulatory neurotransmitters
has been tested on the isolated Limulus heart. Three of the peptides
(DEGHKMLYFamide, GHSLLHFamide, and PDHHMMYFamide) produce dose-depende
nt decreases in both amplitude and rate of the heart contractions, whe
reas DHGNMLYFamide reduces only the amplitude of the heartbeat. All fo
ur peptides differ in threshold, potency and duration of their effects
.