Novel diet consumption and body weight gain are reduced in rats chronically infused with lithium chloride: mediation by the chemosensitive area postrema.
The effects of chronic lithium chloride infusions on consumption of, and subsequent preferences for, a novel diet were examined in rats with ablations of the area postrema (AP) and sham-lesioned control rats. Osmotic minipumps (Alza), filled with a saturated aqueous solution of LiCl (63 g/100 ml), were implanted in the peritoneal cavity of half of the lesioned rats (n = 9) and half of the control rats (n = 8). The remaining rats received empty pumps (n = 9 and n = 7 for lesioned and controls, respectively). The LiCl or sham drug phase was paired with free access to a highly palatable novel diet (AIN diet) during a 7-day conditioning period. Subsequent preferences for the novel diet relative to a familiar diet (ground Purina lab pellets) were determined using a two-food choice procedure. The only group to show a persistent and significant reduction in novel food consumption during the conditioning phase was the sham-lesioned group infused with LiCl (p < 0.01). This group also exhibited a marked aversion for the novel diet, indicative of a conditioned food aversion (CFA), during the preference tests. No significant differences in novel diet consumption or in novel diet preference were found between the two AP-lesioned groups. This study provides evidence that anorexia and CFAs to a novel diet, induced with chronic infusions of lithium, are abolished by destruction of the chemosensitive area postrema.
Eckel
L A
LA
Neuroscience Program, University of Western Ontario, London, Canada.
Ossenkopp
K P
KP
D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects; D004032:Diet; D004435:Eating / Q000187:drug effects*; D005518:Food Preferences / Q000187:drug effects; D008094:Lithium / Q000494:pharmacology*; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D015430:Weight Gain / Q000187:drug effects*
D008094:Lithium