Effects of omega-3 fatty acids on orexigenic and anorexigenic modulators at the onset of anorexia.
In cancer anorexia, a decrease in food intake (FI) occurs concomitant with changes in orexigenic peptides such as neuropeptide Y (NPY) and anorexigenic peptides such as alpha-melanocyte-stimulating hormone (alpha-MSH) and anorexigenic neurotransmitter serotonin. omega-3 Fatty acid (omega-3FA) inhibits cytokine synthesis, and delays tumor appearance, tumor growth, and onset of anorexia in tumor-bearing rats. We hypothesize that, in cancer anorexia, omega-3FA is associated with quantitative reversal of hypothalamic NPY, alpha-MSH, and serotonin receptor (5-HT(1B)-receptor) enhancing FI. Fischer rats were divided into: MCA tumor bearing fed chow (TB-Chow) or omega-3FA diet (TB-omega-3FA) and controls: non-tumor bearing fed chow (NTB-Chow) or omega-3FA diet (NTB-omega-3FA). Rats were euthanized at anorexia and brains were removed for hypothalamic immunohistochemical study, using NPY, alpha-MSH, and 5-HT(1B)-receptor-specific antibodies and slides assessed by image analysis. Immunostaining specificity was controlled by omission of primary or secondary antibodies and pre-absorption test. At anorexia, FI decreased (P < 0.05) in TB-Chow but did not change in TB-omega-3FA rats. In TB-omega-3FA vs. TB-Chow, NPY immunoreactivity increased 38% in arcuate nucleus (ARC; P < 0.05), and 50% in magnocellular paraventricular nucleus (mPVN; P < 0.05). alpha-MSH decreased 64% in ARC and 29% in mPVN (P < 0.05). 5-HT(1B)-receptor immunoreactivity decreased 13% only in supraoptic nucleus (P < 0.05). No immunoreactivity was found in the control sections. omega-3FA modified hypothalamic peptides and 5-HT-(1B)-receptor immunoreactivity at anorexia, concomitant with an increase in FI, were probably mediated by omega-3FA inhibition of tumor-induced cytokines.
Ramos
Eduardo J B
EJ
Department of Surgery, Surgical Metabolism and Nutrition Laboratory, Neuroscience Program, University Hospital, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
Romanova
Irina V
IV
Suzuki
Susumu
S
Chen
Chung
C
Ugrumov
Michael V
MV
Sato
Tomoi
T
Goncalves
Carolina G
CG
Meguid
Michael M
MM
D000704:Analysis of Variance; D000818:Animals; D000855:Anorexia / Q000209:etiology / Q000378:metabolism* / Q000517:prevention & control; D001069:Appetite Regulation / Q000502:physiology*; D004041:Dietary Fats / Q000627:therapeutic use; D015525:Fatty Acids, Omega-3 / Q000502:physiology* / Q000627:therapeutic use; D007031:Hypothalamus / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D009478:Neuropeptide Y / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D044302:Receptor, Serotonin, 5-HT1B / Q000378:metabolism; D012513:Sarcoma, Experimental / Q000150:complications / Q000178:diet therapy / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism; D012983:Soft Tissue Neoplasms / Q000150:complications / Q000178:diet therapy / Q000378:metabolism; D000521:alpha-MSH / Q000378:metabolism
D004041:Dietary Fats; D015525:Fatty Acids, Omega-3; D009478:Neuropeptide Y; D044302:Receptor, Serotonin, 5-HT1B; D012701:Serotonin; D000521:alpha-MSH