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Immunohistochemical distribution of glucose‐dependent insulinotropic polypeptide in the adult rat brain
Author(s) -
Nyberg Jenny,
Jacobsson Calle,
Anderson Michelle F.,
Eriksson Peter S.
Publication year - 2007
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.21349
Subject(s) - colocalization , medicine , endocrinology , gastric inhibitory polypeptide , biology , olfactory bulb , glial fibrillary acidic protein , substantia nigra , hypothalamus , hippocampus , neun , anterior olfactory nucleus , cerebellum , immunohistochemistry , glucagon , central nervous system , neuroscience , dopamine , dopaminergic , insulin , olfactory tubercle
We have previously demonstrated that glucose‐dependent insulinotropic polypeptide (GIP; gastric inhibitory polypeptide) is present in the adult rat hippocampus. This finding leads to the conclusion that all members of the secretin‐glucagon family of gastrointestinal regulatory polypeptides can be found in the brain. To investigate the localization of GIP‐producing cells, we used immunohistochemistry on sections of the adult rat brain. High levels of GIP immunoreactivity were observed in the olfactory bulb, hippocampus, and Purkinje cells in the cerebellum. Moreover, a moderate but distinct GIP immunoreactivity was observed in the cerebral cortex, amygdala, substantia nigra, and lateral septal nucleus as well as in several nuclei in the thalamus, hypothalamus, and brainstem. GIP immunoreactivity was frequently found to colocalize with the neuronal marker NeuN but never with the glial marker glial fibrillary acidic protein. Thus, GIP appears to be mainly neuronal to its distribution. This widespread distribution of GIP‐immunoreactive cells suggests the involvement of GIP in various neuronal functions and suggests that GIP may act as a neurotransmitter or neuromodulator. This is the first characterization of the anatomical distribution of GIP‐immunoreactive cells in the rat brain providing an anatomical framework for future investigations regarding the functions of GIP in the central nervous system. © 2007 Wiley‐Liss, Inc.