Ca(2+)-regulated, neurosecretory granule channel involved in release from neurohypophysial terminals.
Ion channels from bovine neurohypophysial secretory granules (NSG) were incorporated into artificial lipid bilayers. Specific antibodies against identified synaptic vesicle proteins were tested on such incorporated channel activity and on peptide release from rat permeabilized neurohypophysial terminals. Both the NSG cation channel and Ca(2+)-dependent release were inhibited by only SY-38, a monoclonal antibody directed against the C-terminus of synaptophysin. SY-38 and Ca(2+) altered both the gating and conductance of the NSG cation channel, but in opposite ways. The close correlation between SY-38 effects on Ca(2+)-dependent channel activity and release leads us to conclude that this synaptophysin-like NSG channel is directly involved in peptide secretion from these central nervous system terminals.
Yin
Yong
Y
Department of Physiology and Program in Neuroscience, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA.
Dayanithi
Govindan
G
Lemos
José R
JR
D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism; D002118:Calcium / Q000502:physiology*; D002417:Cattle; D003594:Cytoplasmic Granules / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004594:Electrophysiology; D015151:Immunoblotting; D066298:In Vitro Techniques; D007473:Ion Channels / Q000378:metabolism*; D008051:Lipid Bilayers; D008081:Liposomes; D008565:Membrane Proteins / Q000378:metabolism; D009490:Neurosecretory Systems / Q000502:physiology*; D018408:Patch-Clamp Techniques; D010904:Pituitary Gland, Posterior / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000378:metabolism*; D013572:Synaptic Vesicles / Q000378:metabolism; D016708:Synaptophysin / Q000378:metabolism
D007473:Ion Channels; D008051:Lipid Bilayers; D008081:Liposomes; D008565:Membrane Proteins; D016708:Synaptophysin; D001127:Arginine Vasopressin; D002118:Calcium