Basomedial hypothalamic injections of neuropeptide Y conjugated to saporin selectively disrupt hypothalamic controls of food intake
Document Type
Article
Publication Date
3-1-2005
Publication Title
Endocrinology
ISSN
0013-7227
Volume
146
Issue/No.
3
First Page
1179
Last Page
91
Abstract
Neuropeptide Y (NPY) conjugated to saporin (NPY-SAP), a ribosomal inactivating toxin, is a newly developed compound designed to selectively target and lesion NPY receptor-expressing cells. We injected NPY-SAP into the basomedial hypothalamus (BMH), just dorsal to the arcuate nucleus (ARC), to investigate its neurotoxicity and to determine whether ARC NPY neurons are required for glucoprivic feeding. We found that NPY-SAP profoundly reduced NPY Y1 receptor and alpha MSH immunoreactivity, as well as NPY, Agouti gene-related protein (AGRP), and cocaine and amphetamine-related transcript mRNA expression in the BMH. NPY-SAP lesions were localized to the injection site with no evidence of retrograde transport by hindbrain NPY neurons with BMH terminals. These lesions impaired responses to intracerebroventricular (icv) leptin (5 microg/5 microl x d) and ghrelin (2 microg/5 microl), which are thought to alter feeding primarily by actions on ARC NPY/AGRP and proopiomelanocortin/cocaine and amphetamine-related transcript neurons. However, the hypothesis that NPY/AGRP neurons are required downstream mediators of glucoprivic feeding was not supported. Although NPY/AGRP neurons were destroyed by NPY-SAP, the lesion did not impair either the feeding or the hyperglycemic response to 2-deoxy-D-glucose-induced blockade of glycolysis use. Similarly, responses to glucagon-like peptide-1 (GLP-1, 5 microg/3 microl icv), NPY (5 microg/3 microl icv), cholecystokinin octapeptide (4 microg/kg ip), and beta-mercaptoacetate (68 mg/kg ip) were not altered by the NPY-SAP lesion. Thus, NPY-SAP destroyed NPY receptor-expressing neurons in the ARC and selectively disrupted controls of feeding dependent on those neurons but did not disrupt peptidergic or metabolic controls dependent upon circuitry outside the BMH.
NSUWorks Citation
Bugarith, Kishor; Dinh, Thu T.; Li, Ai-Jun; Speth, Robert C.; and Ritter, Sue, "Basomedial hypothalamic injections of neuropeptide Y conjugated to saporin selectively disrupt hypothalamic controls of food intake" (2005). HPD Articles. 80.
https://nsuworks.nova.edu/hpd_facarticles/80
ORCID ID
0000-0002-6434-2198
DOI
10.1210/en.2004-1166
Copyright
Copyright © 2005 by The Endocrine Society
