Activation of the central melanocortin system chronically reduces body mass without the necessity of long-term caloric restriction.

Melanotan II (MTII) is a potent appetite suppressor that rapidly reduces body mass. Given the rapid loss of anorexic response upon chronic MTII treatment, most investigations have focused on the initial physiological adaptations. However, other evidence supports MTII as a long-term modulator of energy balance that remains to be established. Therefore, we examined the chronic effects of MTII on energy homeostasis. MTII (high or low dose) or artificial cerebrospinal fluid (aCSF) was infused into the lateral ventricle of the brain of 6-month-old F344BN rats (6-7/group) over 40 days. MTII suppressed appetite in a dose-dependent manner (P < 0.05). Although food intake promptly rose back to control level, body mass was persistently reduced in both MTII groups (P < 0.01). At day 40, both MTII groups displayed lower adiposity than the aCSF animals (P < 0.01). These results show that MTII chronically reduces body mass without the requirement of long-term caloric restriction. Our study proposes that food restriction helps initiate mass loss; however, combined with a secondary pharmacological approach preserving a negative energy balance state over time may help combat obesity.

The acute effect of pseudoephedrine on choroidal thickness.

PURPOSE: To investigate the acute effects of pseudoephedrine (PE) on choroidal thickness in healthy young patients. METHODS: Fifty patients with nasal and sinus congestion who were prescribed 60 mg oral PE at the otolaryngology department were recruited for this study. The enhanced depth imaging (EDI) optic coherence tomography (OCT) (Spectralis OCT; Heidelberg Engineering, Heidelberg, Germany) choroidal thickness measurements were performed at baseline and 1, 3 and 6 hours at 7 points. RESULTS: The right eyes of 50 healthy subjects (22 women and 28 men) were included in this study. The mean choroidal thickness at fovea was 293.12 µm, 279.80 µm, 295.80 µm, and 294.52 µm at baseline, 1, 3 and 6 hours respectively. A significant reduction in choroidal thickness versus baseline was observed at all points at 1 hour. CONCLUSIONS: The choroidal thickness decreased 1 hour after oral administration of PE and returned to baseline thickness at 3 hours. We suppose that this transient decrease might be associated with vasoconstriction due to activation of sympathetic alpha adrenoceptors.