Regulatory volume decrease in neurons ofAplysia brasiliana

✍ Scribed by Scemes, Eliana ;Cassola, Antônio C.

• Book ID: 102894380
• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 794 KB
• Volume: 272
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402720502

✦ Synopsis

Abstract

Aplysia brasiliana is an osmoconforming mollusc; the osmolality of its extracellular fluid follows that of the external media. This investigation analyzes the volume changes of isolated neuron bodies exposed to hypotonic shocks. The abdominal ganglion was isolated, and the volumes of neuron bodies as well as intracellular K^+^ concentration were measured. Hypotonic shocks induce a rapid swelling followed by a slower restoration of cell volume. The regulatory volume decrease (RVD) restores cell volume to its control value. Ba^2+^ slows RVD without blocking it. Furosemide (in the μM range) completely and reversibly blocks the regulatory volume decrease. On return to isotonic solution after RVD, cell shrinkage was only detected when furosemide was present. It is concluded that neuron bodies of A. brasiliana display efficient processes for volume regulation, based on a conductive pathway and a furosemide‐sensitive transport mechanism, which is probably the Na‐2Cl‐K cotransporter. A model simulation provides additional support to this hypothesis. © 1995 Wiley‐Liss, Inc.