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The interaction of metergoline, a 5-HT receptor blocker, and dexfenfluramine in human feeding
1Academic Unit of Human Psychopharmacology, Medical College of St. Bartholomew's Hospital, London, U.K.
Abstract:
Use of the 5-HT antagonist metergoline (MTG) has shown that dexfenfluramine (d-FF) influences food intake in animals via serotoninergic neurones. This study examined the interaction between d-FF and MTG in humans. Healthy male volunteers reported singly at 8:45 A.M. on four weekly occasions following an overnight fast. At 9:00 A.M. they received 30 mg d-FF or matching placebo and at 11:00 A.M. 4 mg MTG or placebo. Hunger and satiety were assessed hourly using visual analog scales (VAS). Subjects had access to a 4-channel automated food dispenser (AFD) from 1:15 to 3:15 P.M. Delivery and recording of each portion of known energy value was contingent on an appropriate button push. Subjects were offered two nonsweet snacks, plus fruit and a chocolate biscuit chosen to each subject's preference. Results for 13 subjects are reported. d-FF reduced hunger VAS, MTG had no effect on hunger and did not attenuate the effect of d-FF. d-FF reduced total food intake by 1306 kJ (312 kcal p less than 0.01) at 120 min. MTG increased food intake and attenuated the effect of d-FF on food intake but not significantly. d-FF markedly reduced the intake of nonsweet food; this was attenuated by MTG which alone had no effect on nonsweet food. d-FF had no effect on the intake of sweet tasting food during the first hour; by 120 min it had reduced energy intake by 342 kJ (82 kcal, t = 1.34, n.s.).(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Dexfenfluramine (d-FF) reduced hunger and food intake in humans, particularly nonsweet foods. Metergoline (MTG) alone did not affect hunger but increased food intake and partially blocked d-FF's appetite-suppressing effects.
Area of Science:
- Neuroscience
- Pharmacology
- Human Physiology
Background:
- Dexfenfluramine (d-FF) is known to influence food intake via serotoninergic pathways in animals.
- The 5-HT antagonist metergoline (MTG) has been used to study these mechanisms.
Purpose of the Study:
- To investigate the interaction between dexfenfluramine (d-FF) and metergoline (MTG) in humans regarding appetite regulation.
- To assess the effects of d-FF and MTG on hunger, satiety, and food consumption in healthy male volunteers.
Main Methods:
- Double-blind, placebo-controlled study with healthy male volunteers.
- Administration of d-FF (30 mg) or placebo, followed by MTG (4 mg) or placebo.
- Assessment of hunger and satiety using visual analog scales (VAS) and measurement of food intake via an automated food dispenser (AFD).
Main Results:
- d-FF significantly reduced hunger and total food intake (1306 kJ / 312 kcal).
- MTG alone increased food intake and attenuated d-FF's effect on total food intake, though not significantly.
- d-FF primarily reduced nonsweet food intake, an effect partially attenuated by MTG.
Conclusions:
- Dexfenfluramine effectively reduces appetite and food intake in humans, acting through serotoninergic mechanisms.
- Metergoline may partially counteract the appetite-suppressing effects of dexfenfluramine.
- The findings suggest a complex interaction within the serotoninergic system influencing human appetite for different food types.
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