LEP and obesity due to melanocortin 4 receptor deficiency: Oral proprioceptive signals modulate the hypothalamic histamine neurons, which are concordant with the leptin signaling system.29 One study reported that the serum leptin level within 3 hours after a meal was changed after toothbrushing in non-obese young men.30 This suggests that mechanical stimulation of the gingiva by toothbrushing may play a role in appetite regulation by influencing leptin, which can control obesity.