Complex carbohydrate composition of large dense-cored vesicles from sympathetic nerve

Area of Science:

• Neuroscience
• Biochemistry
• Cell Biology

Background:

• Noradrenergic vesicles store neurotransmitters in sympathetic nerve endings.
• Chromaffin granules share similarities with synaptic vesicles but have distinct compositions.
• Understanding vesicle composition is crucial for neurotransmission research.

Purpose of the Study:

• To characterize the glycoprotein and ganglioside composition of highly purified noradrenergic vesicles.
• To compare the molecular makeup of noradrenergic vesicles with bovine chromaffin granules.
• To investigate the types and structures of oligosaccharides and gangliosides present in noradrenergic vesicles.

Main Methods:

• Isolation of noradrenergic vesicles via sucrose-D2O density gradient centrifugation.
• Quantification of glycoprotein hexosamine and sialic acid.
• Analysis of oligosaccharide structures using sequential lectin affinity chromatography.
• Detection and characterization of gangliosides using thin-layer chromatography and cholera toxin binding.

Main Results:

• Noradrenergic vesicles showed similar glycoprotein hexosamine and sialic acid concentrations to chromaffin granules.
• Oligosaccharides in noradrenergic vesicles were predominantly complex tri- and tetraantennary types, unlike chromaffin granule glycoproteins.
• Vesicles contained significant heparan sulfate but low chondroitin sulfate.
• Ganglioside sialic acid concentration was higher in vesicles than in crude membranes, with distinct molecular species.

Conclusions:

• Noradrenergic vesicles possess a distinct oligosaccharide profile compared to chromaffin granules.
• The ganglioside composition of noradrenergic vesicles differs from bovine brain gangliosides.
• These compositional differences may reflect specialized roles in noradrenergic neurotransmission.