Intravenous self-administration of phentermine in food-deprived rats: effects of abrupt refeeding and saline substitution.
The objectives in these experiments were to determine the effects on intravenous phentermine self-administration of abrupt refeeding and of saline substitution in food-deprived rats. In Experiment 1, 32 naive rats, reduced to 80% free-feeding weight (FFW), were assigned randomly to four equal-sized groups. Two groups self-administered phentermine, the other two saline over two consecutive six-day phases. In phase 1, all animals were maintained at 80% FFW, while in phase 2, one phentermine- and one saline-reinforced group was abruptly food satiated. Results showed that phentermine self-administration was suppressed. In Experiment 2, another 32 naive rats were assigned to four equal-sized groups and tested over two consecutive six-day phases. Two groups were FF, the other two were reduced to 80% FFW. In phase 1, a group of FF and 80% FFW animals self-administered phentermine, the other two saline, while in phase 2, treatments were reversed: previously phentermine-reinforced animals self-administered saline and vice versa. Findings showed that 80% FFW rats rapidly discriminate the introduction or removal of phentermine and alter responding accordingly, while FF animals respond at low rates throughout.
D000818:Animals; D001835:Body Weight; D005508:Food Deprivation; D008297:Male; D010645:Phentermine / Q000008:administration & dosage*; D051381:Rats; D011919:Rats, Inbred Strains; D012054:Reinforcement, Psychology; D012965:Sodium Chloride / Q000008:administration & dosage
D012965:Sodium Chloride; D010645:Phentermine