Table 1.
Participant Baseline Characteristics.
Table 2.
Plasma phenylalanine (PHE) and tyrosine (TYR) concentrations (μmol/l), and ratios of tyrosine and phenylalanine to large neutral amino acids (LNAA) at baseline (am) and 4 hour following amino acid ingestion (pm).
Fig 1.
Effect of acute phenylalanine and tyrosine depletion (APTD) on startle eye-blink amplitudes to underweight and healthy female body stimuli (relative to neutral cues) in individuals recovered from anorexia nervosa (AN REC, n = 15) and healthy controls (HC, n = 14).
In the balanced condition (BAL), AN REC showed decreased startle potentiation (an appetitive response) to underweight (5.18 ± 0.58) relative to neutral (5.30 ± 0.54) cues, while HC displayed increased startle potentiation (an aversive response) to underweight (5.35 ± 0.65) relative to neutral (5.19 ± 0.75) cues. In the low DA condition (APTD), AN REC perceived underweight stimuli (5.32 ± 0.53) as more aversive than neutral cues (5.30 ± 0.50), while HC perceived neutral stimuli (5.43 ± 0.56) as more aversive than underweight cues (5.38 ± 0.69); however, during APTD, the differences were not significant. The repeated measures ANOVA was based on the log transformed startle eye-blink potentiations (in millivolts) for AN REC in the BAL (Neutral: 227.43 ± 124.19; Underweight: 204.39 ± 105.90; Healthy: 210.52 ± 94.51) and APTD conditions (Neutral: 224.77 ± 113.62; Underweight: 230.48 ± 118.95; Healthy: 223.19 ± 125.10), and for HC in the BAL (Neutral: 229.66 ± 165.67; Underweight: 254.88 ± 168.49; Healthy: 236.91 ± 159.35) and APTD conditions (Neutral: 259.87 ± 131.95; Underweight: 255.34 ± 133.09; Healthy: 255.01 ± 140.09). Data are expressed as Means ± SD. *P ≤ 0.05. ANOVA: analysis of variance. SD: standard deviation.
Fig 2.
Effect of acute phenylalanine and tyrosine depletion (APTD) on startle eye-blink amplitudes to physically active and non-active body stimuli (relative to neutral cues) in individuals recovered from anorexia nervosa (AN REC, n = 15) and healthy controls (HC, n = 14).
In the balanced condition (BAL), AN REC tended towards decreased startle potentiation (an appetitive response) to active (5.21 ± 0.55) relative to non-active cues (5.30 ± 0.51), while HC displayed increased startle potentiation (an aversive response) to active (5.29 ± 0.68) relative to neutral (5.19 ± 0.75) cues. In the low DA condition (APTD), AN REC perceived active stimuli (5.44 ± 0.67) as more aversive than neutral cues (5.30 ± 0.50), while HC perceived neutral stimuli (5.43 ± 0.56) as more aversive than non-active cues (5.34 ± 0.54); however, differences did not reach significance during APTD. The repeated measures ANOVA was based on the log transformed startle eye-blink potentiations (in millivolts) for AN REC in the BAL (Neutral: 227.43 ± 124.19; Active: 207.19 ± 99.74; Non-active: 222.70 ± 101.74) and APTD conditions (Neutral: 224.77 ± 113.62; Active: 292.60 ± 263.04; Non-active: 221.80 ± 113.70) and for HC in the BAL (Neutral: 229.66 ± 165.67; Active: 243.64 ± 162.38; Non-active: 231.55 ± 160.60) and APTD conditions (Neutral: 259.87 ± 131.95; Active: 246.08 ± 113.52; Non-active: 235.52 ± 122.55). Data are expressed as Means ± SD. *P ≤ 0.10. ANOVA: analysis of variance. SD: standard deviation.