Characterization and localization of galanin receptors in human entorhinal cortex

Document Type

Article

Abstract

The neuropeptide galanin (GAL) has a widespread distribution throughout the human cortex. The entorhinal cortex (ENT) plays a crucial role in the transfer of cortico-cortical information related to memory and displays severe degeneration in Alzheimer's disease (AD). However, very little is known about the pharmacology of the GAL receptor (GALR) in normal human ENT. Therefore, we pharmacologically visualized their distribution and characterized GALRs using in vitro receptor autoradiography and radioligand binding assays. Autoradiograms revealed intense GALR labeling, mainly in the substantia innominata, hypothalamus, the bed nucleus of the stria terminalis and within layers 2 and 4 of the ENT. Kinetic experiments showed that saturation of GALR sites by [125I]GAL (human) (hGAL) occurred within 2 h and that this binding readily reversed in the presence of a GTP analog, but not in the presence of excess unlabeled hGAL. Analysis of [125I]hGAL binding data from saturation experiments gave K(D) values of 98.6±21.6 pM, B(max) values of 52.9±32.4 fmol/mg protein and identified a high and low affinity state of the GALR. The presence of 5'-guanylylimidodiphosphate (GppNHp) or NaCl reduced the agonist labeling of hGALR in ENT membranes. Copyright (C) 1998 Elsevier Science B.V.

Keywords

Aging, Alzheimer's disease, Autoradiography, Cortical, GppNHp, Neuropeptides

Publication Date

2-27-1998

Publication Title

Regulatory Peptides

ISSN

01670115

Volume

73

Issue

3

First Page

149

Last Page

159

PubMed ID

9556077

Digital Object Identifier (DOI)

10.1016/S0167-0115(97)01067-7

Link to Full Text

Share

COinS