Catecholamine secretion by chemically skinned cultured chromaffin cells

Area of Science:

• Cell Biology
• Neuroscience
• Biochemistry

Background:

• Intact chromaffin cells' secretory system is inaccessible to direct chemical manipulation due to plasmalemma permeability.
• Studying the secretory process requires methods to bypass cell membrane-controlled aspects.

Purpose of the Study:

• To develop a simple procedure for chemically permeabilizing cultured adrenal medullary chromaffin cells.
• To enable direct access of exogenous substances to the cellular secretory machinery for studying exocytosis.

Main Methods:

• Cultured adrenal medullary chromaffin cells were briefly exposed to the detergent saponin for chemical "skinning" (permeabilization).
• The secretory competence of skinned cells was assessed using exogenous calcium and MgATP.
• Catecholamine and dopamine-beta-hydroxylase release was measured under varying calcium concentrations.

Main Results:

• Saponin treatment effectively permeabilized the plasmalemma, allowing access to the secretory machinery.
• Skinned cells retained a fully competent secretory mechanism dependent on exogenous calcium and MgATP.
• Catecholamine and dopamine-beta-hydroxylase release occurred via an exocytotic mechanism, unaffected by several tested drugs.

Conclusions:

• Saponin skinning provides a simple method to access chromaffin cell secretory machinery for chemical manipulation.
• This technique allows for the investigation of cellular components' roles in the secretory process.
• The method is potentially applicable to other exocytotic cells.