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Investigating the satiating effect of protein with disguised liquid preloads
ABSTRACTS
220
body weight (BW): an initial decrease in FI (day 1, -66%) and BW (day 3, -4%); a transient rebound of FI (+ 35%) after dlF withdrawal. In experiment 2 the influence of an accurate pretreatment with a large dose of dlF (100pmol/kg i.p.) on anorectics ED,, values (mg/kg i.p., schedule fed rats) or presynaptic (fluoxetine) and postsynaptic (mCPP) serotoninergic agents. When evaluated before (B) and after (A) dlF pretreatment, ED,, values were unchanged: fluoxetine = 8.94 (B) and 9.90 (A); m CPP = 3.43 (B) and 358 (A). It was concluded that, when administered acutely (100 pmol/kg) or chronically (10 prr.ol/kg b.i.d.), dlF does not modify the functionality of hypothalamic 5HT systems regulating food intake and body weight despite the reported long lasting depletion of brain 5HT.
Effect of Chronic o-Fenfluramine Pretreatment on Frontal Cortex Serotonin Levels and Release. Study with in vivo Microdialysis of Anesthetized Rats. B. LAFERRERE and R. J. WURTMAN. M.I.T., Cambridge, MA 02139,
U.S.A. and HBtel-Dieu,
Paris 75004, France.
Using in uiuomicrodialysis coupled with HPLC-EC, we have studied effects of d-fenfluramine (d-f) on 5-HT release in frontal cortex of anesthetized rats. 5-HT basal release was 19.8 + 2.4 fmol/l5 min. A single dose of d-f (10 mg/kg, i.p.) stimulated 5-HT release after 30 min to 8 10 + 380% of basal release. Among rats receiving d-f (10 mg/kg/day) for 8 days, the basal release of 5-HT was unchanged, but the release of 5-HT evoked by a subsequent dose of d-f (lOmg/kg) was reduced by more than 80%. Chronic pretreatment with d-f (10 mg/kg) lowered 5-HT tissue levels by 70% (4.2 + 0.4 vs. 13.6 + 2.9 pmol/mg). In such animals, all parameters returned to normal after the administration of tryptophan and/or after a washout period of 28 days.
Investigating the Satiating Effect of Protein Preloads. TANYA C. LAMBERT, ANDREW J. HILL
with Disguised Liquid and JOHN E. BLUNDELL.
Biopsychology Group, Psychology Department, Psychiatry Department, Leeds University LS2 9JT, U.K.
Evidence is accumulating concerning the particular satiating power of protein compared to the other macronutrients. The present study evaluated the effects of equicaloric low (8x), medium (38%) and high protein (68%) milkshake preloads (200 kcal) on hunger motivation and food intake in eight normal weight volunteers. These overtly similar preloads significantly decreased energy intake in a test meal 1 h later by 11, 19 and 20% respectively, compared to a water preload control. Ratings of hunger motivation were similarly depressed. Withdrawing the normally available sensory and cognitive cues does not abolish the satiating effect of protein, and is evidence for physiological mediation of the effect.
Mechanisms of the Anorexia During Bacterial Infection. W. LANGHANS, E. SCHARRER. Switzerland.
Gram Positive
and Gram Negative
R. HARLACHER, G. BALKOWSKI and Swiss Federal Institute of Technology and University of Zurich, Zurich,
Muramyl dipeptide (MDP, 16OOpg/kg KG, i.p.), the minimal immunologically active structure of gram positive bacterial cell walls, inhibited feeding in rats by decreasing meal frequency without affecting meal size. We have previously reported similar results for Escherichia coli lipopolysaccaride (LPS, 50-250 pg/kg body weight). Indomethacin (2.5 mg/kg body weight), which attenuated the anorectic effect of LPS, also attenuated the anorectic effect of MDP. Finally, MDP and LPS, both, led to a conditioned taste aversion. Therefore, a conditioned taste aversion may contribute to the anorexia during gram positive and gram negative bacterial infection and the underlying mechanism may be similar in both cases.
220
body weight (BW): an initial decrease in FI (day 1, -66%) and BW (day 3, -4%); a transient rebound of FI (+ 35%) after dlF withdrawal. In experiment 2 the influence of an accurate pretreatment with a large dose of dlF (100pmol/kg i.p.) on anorectics ED,, values (mg/kg i.p., schedule fed rats) or presynaptic (fluoxetine) and postsynaptic (mCPP) serotoninergic agents. When evaluated before (B) and after (A) dlF pretreatment, ED,, values were unchanged: fluoxetine = 8.94 (B) and 9.90 (A); m CPP = 3.43 (B) and 358 (A). It was concluded that, when administered acutely (100 pmol/kg) or chronically (10 prr.ol/kg b.i.d.), dlF does not modify the functionality of hypothalamic 5HT systems regulating food intake and body weight despite the reported long lasting depletion of brain 5HT.
Effect of Chronic o-Fenfluramine Pretreatment on Frontal Cortex Serotonin Levels and Release. Study with in vivo Microdialysis of Anesthetized Rats. B. LAFERRERE and R. J. WURTMAN. M.I.T., Cambridge, MA 02139,
U.S.A. and HBtel-Dieu,
Paris 75004, France.
Using in uiuomicrodialysis coupled with HPLC-EC, we have studied effects of d-fenfluramine (d-f) on 5-HT release in frontal cortex of anesthetized rats. 5-HT basal release was 19.8 + 2.4 fmol/l5 min. A single dose of d-f (10 mg/kg, i.p.) stimulated 5-HT release after 30 min to 8 10 + 380% of basal release. Among rats receiving d-f (10 mg/kg/day) for 8 days, the basal release of 5-HT was unchanged, but the release of 5-HT evoked by a subsequent dose of d-f (lOmg/kg) was reduced by more than 80%. Chronic pretreatment with d-f (10 mg/kg) lowered 5-HT tissue levels by 70% (4.2 + 0.4 vs. 13.6 + 2.9 pmol/mg). In such animals, all parameters returned to normal after the administration of tryptophan and/or after a washout period of 28 days.
Investigating the Satiating Effect of Protein Preloads. TANYA C. LAMBERT, ANDREW J. HILL
with Disguised Liquid and JOHN E. BLUNDELL.
Biopsychology Group, Psychology Department, Psychiatry Department, Leeds University LS2 9JT, U.K.
Evidence is accumulating concerning the particular satiating power of protein compared to the other macronutrients. The present study evaluated the effects of equicaloric low (8x), medium (38%) and high protein (68%) milkshake preloads (200 kcal) on hunger motivation and food intake in eight normal weight volunteers. These overtly similar preloads significantly decreased energy intake in a test meal 1 h later by 11, 19 and 20% respectively, compared to a water preload control. Ratings of hunger motivation were similarly depressed. Withdrawing the normally available sensory and cognitive cues does not abolish the satiating effect of protein, and is evidence for physiological mediation of the effect.
Mechanisms of the Anorexia During Bacterial Infection. W. LANGHANS, E. SCHARRER. Switzerland.
Gram Positive
and Gram Negative
R. HARLACHER, G. BALKOWSKI and Swiss Federal Institute of Technology and University of Zurich, Zurich,
Muramyl dipeptide (MDP, 16OOpg/kg KG, i.p.), the minimal immunologically active structure of gram positive bacterial cell walls, inhibited feeding in rats by decreasing meal frequency without affecting meal size. We have previously reported similar results for Escherichia coli lipopolysaccaride (LPS, 50-250 pg/kg body weight). Indomethacin (2.5 mg/kg body weight), which attenuated the anorectic effect of LPS, also attenuated the anorectic effect of MDP. Finally, MDP and LPS, both, led to a conditioned taste aversion. Therefore, a conditioned taste aversion may contribute to the anorexia during gram positive and gram negative bacterial infection and the underlying mechanism may be similar in both cases.