title: Characterization of gastrin-releasing peptide immunoreactivity in distinct storage particles in guinea pig myenteric and Torpedo electromotor neurones.
abstract: Using high resolution centrifugal density-gradient separation of cytoplasmic extracts of guinea pig myenteric plexus and Torpedo electric tissue, we have succeeded in isolating fractions of storage particles rich in gastrin-releasing peptide (GRP). In extracts of myenteric plexus and gradients derived therefrom, the 10-amino acid GRP peptide (GRP-10) was the sole form present; this was bimodally distributed in the gradients, one peak copurifying with Golgi membranes and apparently consisting of immature storage particles, the other with other synaptophysin-rich neuropeptide-containing particles. In extracts of electric organ, a tissue rich in cholinergic electromotor nerve terminals, and gradients derived therefrom, GRP-like immunoreactivity behaved in gel permeation and reversed phase high performance liquid chromatography like the 27-amino acid peptide (GRP-27). About half of the immunoreactivity sedimented in the centrifugal gradient to a region rich in particles containing vasoactive intestinal polypeptide-like immunoreactivity; the remainder was recovered in a very dense region of the gradient containing larger membrane fragments, including synaptosomes. The electromotor nerves and cell bodies also contained GRP-27-like immunoreactivity in relatively high concentration as did the Torpedo gut. It is concluded that this GRP-like peptide is packaged in dense storage particles in the electromotor neurones.
authors.affiliation: Department of Medicine, Queen's University of Belfast, U.K.
authors.forename: C
authors.initials: C
authors.lastname: Shaw
authors.forename: V P
authors.initials: VP
authors.lastname: Whittaker
authors.forename: D V
authors.initials: DV
authors.lastname: Agoston
mesh_terms: D000818:Animals; D002499:Centrifugation, Density Gradient; D002850:Chromatography, Gel; D004557:Electric Organ / Q000294:innervation / Q000378:metabolism*; D019886:Gastrin-Releasing Peptide; D006168:Guinea Pigs; D002479:Inclusion Bodies / Q000032:analysis; D008565:Membrane Proteins / Q000032:analysis; D009197:Myenteric Plexus / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000032:analysis; D009474:Neurons / Q000032:analysis*; D009479:Neuropeptides / Q000032:analysis*; D010455:Peptides / Q000032:analysis*; D016708:Synaptophysin; D013834:Thiamine Pyrophosphatase / Q000378:metabolism; D014101:Torpedo
chemical_list: D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D010455:Peptides; D016708:Synaptophysin; D019886:Gastrin-Releasing Peptide; D013834:Thiamine Pyrophosphatase