Different levels of immunoreactivity for synaptosomal-associated protein of 25 kDa in vasoconstrictor and vasodilator axons of guinea-pigs.
Immunoreactivity (IR) for synaptosomal-associated protein of 25 kDa (SNAP-25) was examined in axons of autonomic vasoconstrictor and vasodilator neurons innervating the lingual and uterine arteries of guinea-pigs. Polyacrylamide gel electrophoresis and immunoblotting of protein extracts demonstrated a SNAP-25-IR band at 25 kDa in both arteries. Quantitative confocal microscopy demonstrated significantly higher levels of SNAP-25-IR in varicosities with IR for vasoactive intestinal peptide (VIP) than in adjacent axons with IR for tyrosine hydroxylase (TH). Levels of SNAP-25-IR in TH-IR axons, relative to adjacent VIP-IR axons, were significantly higher in the lingual artery than the uterine artery. These differences in IR for SNAP-25, a protein considered essential for calcium-dependent exocytosis of neurotransmitters, raise the possibility that mechanisms of transmitter release may vary between different classes of autonomic neurons.
Morris
J L
JL
Department of Anatomy and Histology, Centre for Neuroscience, School of Medicine, Flinders University, G.P.O. Box 2100, S.A. 5001, Adelaide, Australia. judy.morris@flinders.edu.au
Lindberg
C E
CE
Gibbins
I L
IL
D000818:Animals; D001158:Arteries / Q000737:chemistry / Q000294:innervation; D017776:Autonomic Pathways / Q000737:chemistry; D001369:Axons / Q000737:chemistry*; D001923:Brain Chemistry / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D006168:Guinea Pigs; D015151:Immunoblotting; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins / Q000032:analysis*; D050825:Synaptosomal-Associated Protein 25; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis*; D014660:Vasoactive Intestinal Peptide / Q000032:analysis*; D014661:Vasoconstriction / Q000502:physiology; D014664:Vasodilation / Q000502:physiology
D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D050825:Synaptosomal-Associated Protein 25; D014660:Vasoactive Intestinal Peptide; D014446:Tyrosine 3-Monooxygenase