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Tight junctions in the rat parotid gland
S Hashimoto1, S Ochiai, T Muramatsu
1Department of Pathology, Oral Health Science Center, Tokyo Dental College, Tokyo, Japan. sada@tdc.ac.jp
European Journal of Morphology
|September 12, 2000
Summary
Secretion in parotid gland acinar cells increases paracellular permeability. Tight junctions become leaky during exocytosis due to changes in ZO-1 and Occludin distribution, allowing for increased paracellular pathway flow.
Area of Science:
- Cell Biology
- Histology
- Physiology
Background:
- Parotid gland acinar cells are crucial for saliva production.
- Tight junctions regulate paracellular transport between cells.
- Understanding tight junction dynamics during secretion is key to salivary gland function.
Purpose of the Study:
- To investigate the distribution and morphological changes of tight junctions in parotid gland acinar cells during secretion.
- To examine the roles of ZO-1 and Occludin in regulating paracellular permeability.
Main Methods:
- Immunofluorescence and immunogold labeling were used to localize ZO-1 and Occludin in rat parotid glands.
- Rats were injected with IPR to stimulate secretion.
- Parotid glands were analyzed at 10 and 30 minutes post-injection.
Main Results:
- Control glands showed continuous ZO-1 and Occludin at intercellular canaliculi.
- IPR injection caused dilation of canaliculi and particle-like aggregation of ZO-1 and Occludin.
- ZO-1 showed wider cytoplasmic distribution, and actin-associated omega-shaped concavities appeared.
Conclusions:
- Tight junctions become more permeable during exocytosis.
- Changes in ZO-1 distribution and actin filaments lead to Occludin segregation.
- This process increases paracellular pathway leakiness in parotid gland acinar cells.