Identification of neuropeptide Y receptors in cultured astrocytes from neonatal rat brain

✍ Scribed by G. Gimpl; F. Kirchhoff; R. E. Lang; Helmut Kettenmann

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 729 KB
• Volume: 34
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/jnr.490340207

✦ Synopsis

Abstract

Specific binding sites for neuropeptide Y could be demonstrated in primary cultures of astrocytes from neonatal rat brain. Neuropeptide Y binding was saturable, reversible, and temperature dependent as revealed by saturation studies and kinetic experiments. Scatchard analysis of equilibrium binding data indicated a single population of high‐affinity binding sites with respective K~D~ and B~max~ values of 0.43 nM and 6.9 fmol/2.7 × 10^5^ cells. Physiological responses induced by neuropeptide Y could be detected in a distinct subpopulation of cultured astrocytes on the basis of two criteria: (1) electrophysiological responses and (2) single cell measurements of changes in [Ca^2+^]~i~. In that fraction of cells responding (20–70%, varying among cultures from different preparations), brief application of neuropeptide Y led to a membrane potential depolarization, lasting several minutes. When the membrane was clamped close to the resting membrane potential using the whole‐cell patch‐clamp technique, neuropeptide Y induced an inward current with a similar time course as the neuropeptide Y‐induced membrane depolarization. As detected by single cell microfluorimetric (fura‐2) measurements neuropeptide Y induced an increase of [Ca^2+^]~i~ which was caused by the entry of extracellular Ca^2+^. Both the [Ca^2+^]~i~ increase and the electrophysiological responses were unaffected by pretreatment of the astrocytes with pertussis toxin. © 1993 Wiley‐Liss, Inc.