NPF is a 36 amino acid peptide in Drosophila Melanogaster, or fruit flies, that was found to be a homologue of the mammalian Neuropeptide Y hormone (Lee, K., et. al, 2004). NPY is synthesized and secreted by neurons into the peripheral nervous system and central nervous system. It can also be synthesized and secreted from islet cells of the pancreas, and via its Y1 receptor, it inhibits insulin secretion due to glucose. NPY has also been shown to be a potent stimulator in rodents in terms of food intake (Kronenberg, H.M., et. al, 2008). One important difference in the structure of NPF and NPY is that NPF has a Phenylalanine (Phe) residue at the C-terminus, whereas NPY has a Tyrosine (Tyr).
NPF has many diverse functions and affects many important processes in Drosophila, such as: behaviour, alcohol sensitivity, energy homeostasis, circadian rhythm, food intake, body size, reproduction, anxiety, seizure, learning and memory (Lee, G., et. al, 2006).
NPF has a receptor known as NPFR1, which is linked to ethanol sedation. If there is a deficiency in NPF or this receptor, it has been shown that there is also a decrease in alcohol sensitivity. The opposite phenotype can be observed when there is overexpression of NPF or NPFR1 (Wen, T., et. al, 2005).
This same receptor, NPFR1, is linked to food intake as well. The activity of this receptor is mandatory for fasting larvae to participate in what is known as "cold-resistant feeding behaviour" (Lingo, P., et. al, 2007). In other words, these fasted larvae would not eat cold food if their lives depended on it, unless this receptor was active. From this study, it can be suggested that the mammalian NPF-like system (NPY) can play a central role in gustation.
References:
1) Kronenberg, H.M., Melmed, S., Polonsky, K.S., & Larsen, P.R. (2008). Williams Textbook of Endocrinology. 1955. Reprint. Philadelphia, PA: Saunders Elsevier.
2) Lee, G., Bahn, J.H., & Park, J.H. (2006). Sex- and clock-controlled expression of the neuropeptide F gene in Drosophila. PNAS. 103(33); 12580-12585.
3) Lee, K., You, K., Choo, J., Han, Y., & Yu, K. (2004). Drosophila Short Neuropeptide F regulates food intake and body size. The Journal of Biological Chemistry. 279(49); 50781-50789.
4) Lingo, P., Zhao, Z., & Shen, P. (2007). Co-regulation of Cold-Resistant Food Acquisition by Insulin- and Neuropeptide Y-like Systems in Drosophila melanogaster. Neuroscience. 148(2); 371-374.
5) Wen, T., Parrish, C., Wu, D., & Shen, P. (2005). Drosophila neuropeptide F and its receptor, NPFR1, define a signaling pathway that acutely modulates alcohol sensitivity. PNAS. 102(6); 2141-2146.
