Delay of cancer anorexia following intraventricular injection of para-chlorophenylalanine.
Serotonergic mediation of cancer anorexia was investigated in immature female rats following the intraventricular injection of para-chlorophenylalanine (PCPA) or normal saline. Significant anorexia developed 6 days after the induction (IM) of Walker 256 carcinosarcomas in saline-treated rats. Although tumor-bearing rats treated with PCPA ate less than PCPA-injected controls by day 7, their feeding response was significantly greater than that of saline-treated tumor-bearing rats on days 5, 6 and 7. The PCPA treatment had no significant effect on food intake in nontumor-bearing rats. Biochemical analysis revealed significant elevations in plasma free tryptophan, brain tryptophan and brain 5-hydroxyindoleacetic acid in saline-treated tumor-bearing rats. Brain serotonin, 5-hydroxyindoleacetic acid and norepinephrine levels were decreased in PCPA-treated rats. Although these data may provide some support for a serotonergic mediation of cancer anorexia, additional mechanisms are clearly indicated.
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002279:Carcinoma 256, Walker / Q000188:drug therapy*; D004435:Eating / Q000187:drug effects*; D005260:Female; D010134:Fenclonine / Q000494:pharmacology*; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D007276:Injections, Intraventricular; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism
D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D010134:Fenclonine; D009638:Norepinephrine