PRQFVamide, a Novel Pentapeptide Identified From the CNS and Gut of Aplysia

• Published in: Journal of neurophysiology Vol. 89; no. 6; pp. 3114 - 3127
• Main Authors: Furukawa, Y, Nakamaru, K, Sasaki, K, Fujisawa, Y, Minakata, H, Ohta, S, Morishita, F, Matsushima, O, Li, L, Alexeeva, V, Ellis, T. A, Dembrow, N. C, Jing, J, Sweedler, J. V, Weiss, K. R, Vilim, F. S
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01.06.2003
• Subjects: Amides - isolation & purification; Amino Acid Sequence; Animals; Aplysia; Arginine; Blood Vessels - physiology; Blotting, Northern; Central Nervous System - chemistry; Central Nervous System - physiology; Cloning, Molecular; Digestive System - chemistry; Digestive System Physiological Phenomena; Electrophysiology; Ganglia - chemistry; Ganglia - physiology; Glycine; Immunohistochemistry; In Situ Hybridization; Marine; Mass Spectrometry; Muscle Contraction - physiology; Peptides - analysis; Peptides - isolation & purification; Peptides - physiology; Phenylalanine; Proline; Valine
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.00014.2003

1 Graduate School of Science, Department of Biological Science and 2 Instrumental Center for Chemical Analysis, Hiroshima University, Higashi-Hiroshima 739-8526, Japan; 3 Suntory Institute for Bioorganic Research, Shimamoto, Mishima, Osaka 618-8503, Japan; 4 Department of Chemistry and Beckman Institute, University of Illinois, Urbana, Illinois 61801; and 5 Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York, New York 10029 Submitted 7 January 2003; accepted in final form 6 February 2003 We have purified a novel pentapeptide from the Aplysia nervous system using bioassay on gut contractions. The structure of the peptide is Pro-Arg-Gln-Phe-Val-amide (PRQFVa). The precursor for PRQFVa was found to code for 33 copies of PRQFVamide and four related pentapeptides. Peaks corresponding to the predicted masses of all five pentapeptides were detected in Aplysia neurons by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Northern analysis revealed that expression of the precursor is abundant in the abdominal ganglion, much less in the pedal and cerebral ganglia, and rarely seen in the buccal and pleural ganglia. PRQFVa-positive neurons, mapped by immunohistochemistry and in situ hybridization, were present in all the central ganglia. PRQFVa immunopositive processes were observed in the gut, particularly in association with the vasculature. Some arteries and other highly vascularized tissues, such as the gill and the kidney, also contain numerous PRQFVa immunopositive processes. Application of synthetic PRQFVa suppresses not only contractions of the gut but also contractions of vasculature. PRQFVa is expressed in some of the neurons within the feeding circuitry and application of synthetic PRQFVa was found to decrease the excitability of some (B4/5 and B31/32) but not all (B8) neurons of the buccal feeding circuit. Our findings suggest that PRQFVa may act as a modulator within the feeding system as well as in other systems of Aplysia . Address for reprint requests: F. S. Vilim, Dept. of Physiology and Biophysics, Box 1218, Mount Sinai School of Medicine, New York, NY 10029 (E-mail: vilim{at}inka.mssm.edu ).