Li AJ, Ritter S (2003) 2-deoxy-D-glucose (2DG) increases NPY mRNA expression in hindbrain neurons. Neuroscience 2003 Abstracts 615.7. Society for Neuroscience, New Orleans, LA.
Summary: Previous results suggest that the orexigenic peptide, neuropeptide Y (NPY), participates in glucoprivic feeding. NPY mRNA in the hypothalamus is increased by glucoprivation (Sergeyev et al, 2000; Fraley and Ritter, 2003) and injection of anti-NPY antibody into the paraventricular nucleus of the hypothalamus (PVH) impairs glucoprivic feeding (He and Edwards, 1998). The hypothalamus is innervated by both arcuate and hindbrain NPY cell bodies. NPY innervation from the hindbrain is substantial and is derived largely or entirely from cell bodies that co-express norepinephrine or epinephrine. Selective immunotoxin lesions have demonstrated that these hindbrain catecholamine neurons are required for glucoprivic feeding (Ritter et al., 2001), as well as for glucoprivic stimulation of corticosterone secretion (Ritter et al., 2003) and suppression of estrus (I’Anson et al., 2003). However, the specific contribution of hindbrain NPY to these glucoregulatory responses has not been examined. Therefore, we examined NPY mRNA expression in hindbrain catecholamine cell groups 1.5 hr after 2-deoxy-D-glucose (2DG, 250 mg/kg) injection using in situ hybridization. Cell groups A1, A1/C1, the middle portion of C1 and C2, showed a basal level of NPY mRNA signal that was dramatically increased by 2DG. In rostral C1 and in C3, where basal NPY mRNA expression was below detection threshold, the hybridization signal was also significantly increased by 2DG. In cell groups A2, A5, A6 and A7, neither basal nor 2DG-stimulated NPY mRNA expression was detected. PVH microinjection of the retrogradely transported catecholamine immunotoxin, saporin conjugated to anti-dopamine-β-hydroxylase, destroyed hindbrain catecholamine neurons and abolished basal and 2DG-stimulated increases in NPY expression in hindbrain cell groups. These data suggest that hindbrain NPY neurons with projections to the hypothalamus participate in glucoprivic feeding and other glucoregulatory responses.
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