Determinants of increased drug self-administration due to food deprivation.
Changes in oral etonitazene self-administration were compared in four groups of rats that were maintained at 100, 95, 85, or 75% of their pre-experimental free-feeding body weights. Etonitazene (5 micrograms/ml) or water was available for 16 h according to a fixed-ratio (FR) 1 schedule. Each liquid delivery (0.1 ml) was contingent upon a lever-press response. During food deprivation etonitazene intake gradually increased to over two-fold as body weights decreased over 25 sessions; etonitazene intake was inversely proportional to body weight. The 75% weight group showed stereotypy, self-mutilation and large variability in daily etonitazene intake. In another experiment a range of deprivation conditions was studied in a group of six rats with etonitazene (5 micrograms/ml) or water available on an FR 8 schedule during 1-h sessions. When the rats were gradually food satiated, etonitazene-maintained behavior declined but remained higher than water-maintained behavior; however, when they were abruptly food satiated, etonitazene-maintained behavior decreased to low levels.
D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology; D001835:Body Weight; D005502:Food; D005508:Food Deprivation / Q000502:physiology*; D008297:Male; D051381:Rats; D012054:Reinforcement, Psychology; D012527:Satiation / Q000502:physiology; D012646:Self Administration
D001562:Benzimidazoles