Endocannabinoids and energy homeostasis: an update.

The endocannabinoid system (ECS) is a widespread intercellular signaling system that plays a critical role in energy homeostasis, meant as the precise matching of caloric intake with energy expenditure which normally keeps body weight stable over time. Complex interactions between environmental and neurohormonal systems directly contribute to the balance of energy homeostasis. This review highlights established and more recent data on the brain circuits in which the ECS plays an important regulatory role, with focus on the hypothalamus, a region where numerous interacting systems regulating feeding, satiety, stress, and other motivational states coexist. Although not meant as an exhaustive review of the field, this article will discuss how endocannabinoid tone, in addition to reinforcing reward circuitries and modulating food intake and the salience of food, controls lipid and glucose metabolism in several peripheral organs, particularly the liver and adipose tissue. Direct actions in the skeletal muscle and pancreas are also emerging and are briefly discussed. This review provides new perspectives into endocannabinoid control of the neurochemical causes and consequences of energy homeostasis imbalance, a knowledge that might lead to new potential treatments for obesity and related morbidities.

Disruption of prepulse inhibition by 3,4-methylenedioxymethamphetamine (MDMA): comparison between male and female wild-type and 5-HT(1A) receptor knockout mice.

The aim of this study was to investigate the involvement of serotonin-1A (5-HT(1A)) receptors in the effects of 3,4-methylenedioxymetamphetamine (MDMA) on prepulse inhibition of acoustic startle (PPI) by comparing male and female wild-type (WT) mice and 5-HT(1A) receptor knockout (1AKO) mice. MDMA dose-dependently decreased PPI in male and female mice although female mice were more sensitive at the 100-ms inter-stimulus interval (ISI). In male mice, 10 mg/kg MDMA disrupted PPI in 1AKO but not in WT controls. There was no genotype difference at higher or lower doses of MDMA. In female mice, there was no difference between genotypes at any dose of MDMA. Average startle was reduced by 10 mg/kg and 20 mg/kg MDMA similarly in male and female mice and all genotypes. These results show an involvement of 5-HT(1A) receptors in the effect of MDMA on PPI in male, but not female mice.