An adrenal slice preparation for the study of chromaffin cells and their cholinergic innervation

Thin slices (200-300 microm) of adrenal glands were prepared from Wistar rats. Patch-clamp recordings were made from visually identified chromaffin cells using the whole-cell and amphotericin B perforated-patch techniques. Electrophysiological properties of chromaffin cells in slices were similar to those in cultured cells. Catecholamine release from single chromaffin cells or cell clusters in slices was also measured by amperometry. Immunostaining of slices with an antineurofilament antibody revealed the presence of neuronal fibers. Acetylcholine release was stimulated either by raising external [K+] or by focally applying voltage pulses. Nicotinic excitatory postsynaptic currents (EPSCs) were detected, ranging from 20 pA to several hundreds of pA. Amplitude distributions of spontaneous EPSCs revealed clear equidistant peaks, supporting a quantal model for acetylcholine release onto chromaffin cells. The adrenal slice preparation therefore appears to be an excellent model for studying both the cholinergic innervation of chromaffin cells as well as catecholamine release from these cells.