Purpose: In obesity, metabolic and voluntary factors regulate appetite, and a dysregulation of the reward pathway was demonstrated in all addiction disorders. Deep transcranial magnetic stimulation (dTMS) is already used to modulate cerebral dopamine activation in neuro-psychiatric diseases. We presently assess the acute effect of high frequency (HF) and low frequency (LF) dTMS on the modulation of the main neuropeptides and neurotransmitters involved in the reward pathway in obese subjects.
Methods: This study was designed as a double-blind, sham-controlled, randomized clinical trial. Thirty-three obese patients (9 males, 24 females, age 48.1 ± 10.6, BMI 36.4 ± 4.7) were enrolled in the study. All patients were studied during a single dTMS session and blood aliquots were drawn before and after a single dTMS session. Metabolic and neuro-endocrine parameters were evaluated before and after: (1) 18 Hz dTMS (HF, 13 patients); (2) 1 Hz dTMS (LF, 10 patients); (3) Sham treatment (Sham, 10 patients).
Results: No statistically significant variations in metabolic parameters, systolic and diastolic blood pressure, and heart rate were shown acutely. HF showed a significant increase of β-endorphin compared to other groups (p = 0.048); a significant increase of ghrelin in LF (p = 0.041) was also demonstrated.
Conclusions: A single session of HF dTMS treatment determines in obese subjects an acute increase of β-endorphin level, indicating an activation of the reward pathway. The present findings constitute proof of principle for a potential application of this methodology in obesity treatment.
Keywords: Food craving; Ghrelin; Obesity; Transcranial magnetic stimulation; β-endorphin.