Limits...
Cycling of dense core vesicles involved in somatic exocytosis of serotonin by leech neurons.

Trueta C, Kuffler DP, De-Miguel FF - Front Physiol (2012)

Bottom Line: A partial bleaching of the spots followed by another depolarization in the presence of FM1-43 produced restaining of some spots, other spots disappeared, some remained without restaining and new spots were formed.Several hours after electrical stimulation the FM1-43 spots accumulated at the center of the somata.This correlated with electron micrographs of multivesicular bodies releasing their contents near Golgi apparatuses.

View Article: PubMed Central - PubMed

Affiliation: Instituto Nacional de Psiquiatría "Ramón de la Fuente Muñiz," México D. F., México.

ABSTRACT
We studied the cycling of dense core vesicles producing somatic exocytosis of serotonin. Our experiments were made using electron microscopy and vesicle staining with fluorescent dye FM1-43 in Retzius neurons of the leech, which secrete serotonin from clusters of dense core vesicles in a frequency-dependent manner. Electron micrographs of neurons at rest or after 1 Hz stimulation showed two pools of dense core vesicles. A perinuclear pool near Golgi apparatuses, from which vesicles apparently form, and a peripheral pool with vesicle clusters at a distance from the plasma membrane. By contrast, after 20 Hz electrical stimulation 47% of the vesicle clusters were apposed to the plasma membrane, with some omega exocytosis structures. Dense core and small clear vesicles apparently originating from endocytosis were incorporated in multivesicular bodies. In another series of experiments, neurons were stimulated at 20 Hz while bathed in a solution containing peroxidase. Electron micrographs of these neurons contained gold particles coupled to anti-peroxidase antibodies in dense core vesicles and multivesicular bodies located near the plasma membrane. Cultured neurons depolarized with high potassium in the presence of FM1-43 displayed superficial fluorescent spots, each reflecting a vesicle cluster. A partial bleaching of the spots followed by another depolarization in the presence of FM1-43 produced restaining of some spots, other spots disappeared, some remained without restaining and new spots were formed. Several hours after electrical stimulation the FM1-43 spots accumulated at the center of the somata. This correlated with electron micrographs of multivesicular bodies releasing their contents near Golgi apparatuses. Our results suggest that dense core vesicle cycling related to somatic serotonin release involves two steps: the production of clear vesicles and multivesicular bodies after exocytosis, and the formation of new dense core vesicles in the perinuclear region.

No MeSH data available.


Related in: MedlinePlus

Dense core vesicle fusion after electrical stimulation (arrow). To the right of the fusing vesicle are small clear vesicles and cisternae (arrowheads) atypical of somatic clusters before electrical stimulation. This suggests vesicle formation as part of the endocytic pathway. Glial cell fingers (g) can be seen outside the Retzius cell. Scale bar = 250 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3368391&req=5

Figure 4: Dense core vesicle fusion after electrical stimulation (arrow). To the right of the fusing vesicle are small clear vesicles and cisternae (arrowheads) atypical of somatic clusters before electrical stimulation. This suggests vesicle formation as part of the endocytic pathway. Glial cell fingers (g) can be seen outside the Retzius cell. Scale bar = 250 nm.

Mentions: In six neurons fixed after 20 Hz stimulation, 47% of the vesicle clusters were apposed to the plasma membrane (Figure 1E), vs. the 9% of vesicle clusters in neurons stimulated at 1 Hz (Figure 1E). The perinuclear clusters remained in the same region. In the plasma membrane, some vesicles had omega-like appearances indicative of vesicles that had fused with the plasma membrane in response to the electrical stimulation (Figure 4). Multivesicular bodies were commonly located within peripheral vesicle clusters and were surrounded by radial arrays of dense core vesicles (Figure 1D), suggesting that multivesicular bodies had been formed by endocytosis following exocytosis.


Cycling of dense core vesicles involved in somatic exocytosis of serotonin by leech neurons.

Trueta C, Kuffler DP, De-Miguel FF - Front Physiol (2012)

Dense core vesicle fusion after electrical stimulation (arrow). To the right of the fusing vesicle are small clear vesicles and cisternae (arrowheads) atypical of somatic clusters before electrical stimulation. This suggests vesicle formation as part of the endocytic pathway. Glial cell fingers (g) can be seen outside the Retzius cell. Scale bar = 250 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3368391&req=5

Figure 4: Dense core vesicle fusion after electrical stimulation (arrow). To the right of the fusing vesicle are small clear vesicles and cisternae (arrowheads) atypical of somatic clusters before electrical stimulation. This suggests vesicle formation as part of the endocytic pathway. Glial cell fingers (g) can be seen outside the Retzius cell. Scale bar = 250 nm.
Mentions: In six neurons fixed after 20 Hz stimulation, 47% of the vesicle clusters were apposed to the plasma membrane (Figure 1E), vs. the 9% of vesicle clusters in neurons stimulated at 1 Hz (Figure 1E). The perinuclear clusters remained in the same region. In the plasma membrane, some vesicles had omega-like appearances indicative of vesicles that had fused with the plasma membrane in response to the electrical stimulation (Figure 4). Multivesicular bodies were commonly located within peripheral vesicle clusters and were surrounded by radial arrays of dense core vesicles (Figure 1D), suggesting that multivesicular bodies had been formed by endocytosis following exocytosis.

Bottom Line: A partial bleaching of the spots followed by another depolarization in the presence of FM1-43 produced restaining of some spots, other spots disappeared, some remained without restaining and new spots were formed.Several hours after electrical stimulation the FM1-43 spots accumulated at the center of the somata.This correlated with electron micrographs of multivesicular bodies releasing their contents near Golgi apparatuses.

View Article: PubMed Central - PubMed

Affiliation: Instituto Nacional de Psiquiatría "Ramón de la Fuente Muñiz," México D. F., México.

ABSTRACT
We studied the cycling of dense core vesicles producing somatic exocytosis of serotonin. Our experiments were made using electron microscopy and vesicle staining with fluorescent dye FM1-43 in Retzius neurons of the leech, which secrete serotonin from clusters of dense core vesicles in a frequency-dependent manner. Electron micrographs of neurons at rest or after 1 Hz stimulation showed two pools of dense core vesicles. A perinuclear pool near Golgi apparatuses, from which vesicles apparently form, and a peripheral pool with vesicle clusters at a distance from the plasma membrane. By contrast, after 20 Hz electrical stimulation 47% of the vesicle clusters were apposed to the plasma membrane, with some omega exocytosis structures. Dense core and small clear vesicles apparently originating from endocytosis were incorporated in multivesicular bodies. In another series of experiments, neurons were stimulated at 20 Hz while bathed in a solution containing peroxidase. Electron micrographs of these neurons contained gold particles coupled to anti-peroxidase antibodies in dense core vesicles and multivesicular bodies located near the plasma membrane. Cultured neurons depolarized with high potassium in the presence of FM1-43 displayed superficial fluorescent spots, each reflecting a vesicle cluster. A partial bleaching of the spots followed by another depolarization in the presence of FM1-43 produced restaining of some spots, other spots disappeared, some remained without restaining and new spots were formed. Several hours after electrical stimulation the FM1-43 spots accumulated at the center of the somata. This correlated with electron micrographs of multivesicular bodies releasing their contents near Golgi apparatuses. Our results suggest that dense core vesicle cycling related to somatic serotonin release involves two steps: the production of clear vesicles and multivesicular bodies after exocytosis, and the formation of new dense core vesicles in the perinuclear region.

No MeSH data available.


Related in: MedlinePlus