ISSN:
1365-2826
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
γ-aminobutyric acid (GABA) interacts with hypothalamic neuronal pathways regulating feeding behaviour. GABA has been reported to stimulate feeding via both ionotropic GABAA and metabotropic GABAB receptors. The functional form of the GABAB receptor is a heterodimer consisting of GABAB receptor-1 (GABABR1) and GABAB receptor-2 (GABABR2) proteins. Within the heterodimer, the GABA-binding site is localized to GABABR1. In the present study, we used an antiserum to the GABABR1 protein in order to investigate the cellular localization of GABABR1-immunoreactive neurones in discrete hypothalamic regions implicated in the control of body weight. The colocalization of GABABR1 immunoreactivity with different chemical messengers that regulate food intake was analysed. GABABR1-immunoreactive cell bodies were found in the periventricular, paraventricular (PVN), supraoptic, arcuate, ventromedial hypothalamic, dorsomedial hypothalamic, tuberomammillary nuclei and lateral hypothalamic area (LHA). Direct double-labelling showed that glutamic acid decarboxylase (GAD)-positive terminals were in close contact with GABABR1-containing cell bodies located in all these regions. In the ventromedial part of the arcuate nucleus, GABABR1-immunoreactive cell bodies were found to contain neuropeptide Y, agouti-related peptide (AGRP) and GAD. In the ventrolateral part of the arcuate nucleus, GABABR1-immunoreactive cell bodies were shown to contain pro-opiomelanocortin and cocaine- and amphetamine-regulated transcript. In the LHA, GABABR1 immunoreactivity was present in both melanin-concentrating hormone- and orexin-containing cell populations. In the tuberomammillary nucleus, GABABR1-immunoreactive cell bodies expressed histidine decarboxylase, a marker for histamine-containing neurones. In addition, GAD and AGRP were found to be colocalized in some nerve terminals surrounding GABABR1-immunoreactive cell bodies in the parvocellular part of the PVN. The results may provide a morphological basis for the understanding of how GABA regulates the hypothalamic control of food intake and body weight via GABAB receptors.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.1365-2826.2003.00843.x
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