Characterization, by size, density, osmotic fragility, and immunoaffinity, of acetylcholine- and vasoactive intestinal polypeptide-containing storage particles from myenteric neurones of the guinea-pig.
When cytoplasmic extracts of guinea-pig myenteric neurones are submitted to centrifugal density gradient fractionation in a zonal rotor acetylcholine is bimodally distributed in the gradient, in a peak (I) rich in synaptic vesicles of the classic type and in a denser peak (II/VI) rich in densecored vesicles and vasoactive intestinal polypeptide (VIP). The putative stable synaptic vesicle markers synaptophysin (p38), vesicular proteoglycan, and Mg2+-activated ATPase were also bimodally distributed, with a peak coincident with peak I and another, broader peak embracing peak II/VI, and neighbouring peaks of other neuropeptides resolved from peak II/VI by the density gradient separation procedure used. To establish whether the stable markers, acetylcholine and VIP in peak II/VI were present in one particle or several, attempts were made to separate them by particle-exclusion chromatography and differential osmotic fragility. These were unsuccessful, leading us to conclude that the storage particles in peak II/VI contain both neurotransmitters and all three putative stable synaptic vesicle markers. It is suggested that such particles are the counterparts, in cholinergic neurones of the myenteric plexus, of the dense-cored, enkephalin- and noradrenaline-containing vesicles of certain adrenergic neurones and, like the latter, may exist in a precursor-product relationship with the classic synaptic vesicles containing the small-molecular-mass transmitters and found in the same nerve terminals.
Agoston
D V
DV
Max-Planck-Institut für biophysikalische Chemie, Göttingen, F.R.G.
Whittaker
V P
VP
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000032:analysis; D002458:Cell Fractionation; D002499:Centrifugation, Density Gradient; D002845:Chromatography; D019886:Gastrin-Releasing Peptide; D006168:Guinea Pigs; D007163:Immunosorbent Techniques; D008565:Membrane Proteins / Q000032:analysis; D009197:Myenteric Plexus / Q000648:ultrastructure*; D009419:Nerve Tissue Proteins / Q000032:analysis; D009474:Neurons / Q000648:ultrastructure*; D015388:Organelles / Q000032:analysis / Q000502:physiology / Q000648:ultrastructure; D009996:Osmotic Fragility; D010455:Peptides / Q000032:analysis; D013004:Somatostatin / Q000032:analysis; D013373:Substance P / Q000032:analysis; D013572:Synaptic Vesicles / Q000032:analysis / Q000648:ultrastructure; D016708:Synaptophysin; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*
D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D010455:Peptides; D016708:Synaptophysin; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D013004:Somatostatin; D019886:Gastrin-Releasing Peptide; D017301:Ca(2+) Mg(2+)-ATPase; D000109:Acetylcholine