The Journal of comparative neurology
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Growth hormone secretagogue receptor (GHSR) 1a is the only molecularly identified receptor for ghrelin, mediating ghrelin-related effects on eating, body weight, and blood glucose control, among others. The expression pattern of GHSR within the brain has been assessed previously by several neuroanatomical techniques. However, inherent limitations to these techniques and the lack of reliable anti-GHSR antibodies and reporter rodent models that identify GHSR-containing neurons have prevented a more comprehensive functional characterization of ghrelin-responsive neurons. ⋯ In contrast, eGFP expression was low in several midbrain regions and in several hypothalamic nuclei, particularly the arcuate nucleus, where robust GHSR mRNA expression has been well-characterized. eGFP expression in several brainstem nuclei showed high to moderate degrees of colocalization with GHSR mRNA labeling. Further quantitative PCR and electrophysiological analyses of eGFP-labeled hippocampal cells confirmed faithful expression of eGFP within GHSR-containing, ghrelin-responsive neurons. In summary, the GHSR-eGFP reporter mouse model may be a useful tool for studying GHSR function, particularly within the brainstem and hippocampus; however, it underrepresents GHSR expression in nuclei within the hypothalamus and midbrain.