Pancreatic acinar cells: acetylcholine-evoked electrical uncoupling and its ionic dependency

Area of Science:

• Cellular physiology
• Pancreatic acinar cell electrophysiology
• Intercellular communication

Background:

• Pancreatic acinar cells form functional syncytia through electrical coupling.
• Acetylcholine (ACh) is a key regulator of pancreatic secretion and cell-to-cell communication.
• Understanding the mechanisms of ACh-evoked changes in electrical coupling is crucial for pancreatic function.

Purpose of the Study:

• To investigate the effects of acetylcholine (ACh) on electrical coupling between pancreatic acinar cells.
• To elucidate the role of calcium and other ions in ACh-evoked electrical uncoupling.

Main Methods:

• Isolated mouse or rat pancreatic acini were used for electrophysiological recordings.
• Intracellular microelectrodes were inserted into neighboring acinar cells to measure electrical coupling.
• Acetylcholine (ACh) was applied via iontophoresis to stimulate the acini.

Main Results:

• Short ACh pulses (5-10 sec) induced reversible electrical uncoupling between acinar cells.
• This uncoupling was independent of extracellular calcium but dependent on intracellular calcium stores.
• Sustained ACh stimulation led to persistent uncoupling, which was reversed by Ni2+ or Co2+ and dependent on extracellular calcium.

Conclusions:

• ACh evokes electrical uncoupling in pancreatic acinar cells through distinct mechanisms depending on stimulation duration.
• Short ACh stimuli utilize intracellular calcium, while sustained stimuli rely on extracellular calcium for uncoupling.
• These findings highlight the dynamic regulation of intercellular communication in the pancreatic acinus.