CHARACTERIZATION OF MYOMODULIN-RELATED PEPTIDES FROM THE PULMONATE SNAIL HELIX-ASPERSA

Three myomodulin-related peptides-pQLSMLRLamide, PMSMLRLamide, and SLG MLRLamide-have been purified and sequenced from extracts of whole snai ls. The level of immunoreactive myomodulin was shown by HPLC and RIA t o be widely distributed among 26 different snail tissues, with the hig hest levels (higher even than those in the central ganglia) occurring in certain male reproductive organs. Synthetic pQLSMLRLamide modified either the spontaneous rhythmic activity or the resting tone of severa l isolated muscular organs: the aorta, ventricle, upper gut, epiphallu s, flagellum, and spermatheca; but the retractor muscles of the pharyn x, penis, and tentacle were unaffected. (C) 1997 Elsevier Science Inc.