Anionic sites of charge barrier in the guinea pig crista ampullaris

Area of Science:

• Oto-neuroscience
• Cell Biology
• Biochemistry

Background:

• The crista ampullaris in the inner ear plays a role in fluid dynamics.
• Basement membranes are crucial structural and functional components of tissues.
• Understanding charge distribution in basement membranes is key to inner ear physiology.

Purpose of the Study:

• To identify and characterize anionic sites in the epithelial and capillary basement membranes of the crista ampullaris dark cell area in guinea pigs.
• To investigate the influence of furosemide on these anionic sites and associated tissue changes.
• To correlate basement membrane charge distribution with inner ear fluid production or absorption.

Main Methods:

• Application of an immersion method using a cationic tracer, polyethyleneimine (PEI).
• Electron microscopy for observing PEI particle arrangement along the basement membrane.
• Quantitative analysis of PEI particle distribution.
• Control experiments using protamine sulfate and experimental studies with furosemide.

Main Results:

• Anionic sites were visualized as two strata along the basement membranes of the dark cell area.
• Control tests with protamine sulfate reduced PEI particle counts.
• Furosemide treatment induced pathological changes, including interstitial edema, and reduced PEI particle numbers.

Conclusions:

• Polyethyleneimine particles effectively reflect the anionic charge conditions of the basement membrane.
• Alterations in basement membrane charge are implicated in the regulation of inner ear fluid homeostasis.
• These findings provide insights into the mechanisms of inner ear fluid production and absorption.