Altered serotonergic and GABAergic neurotransmission in a mice model of obsessive-compulsive disorder.

There is ample evidence that obsessive-compulsive disorder (OCD) is based on reduced serotonergic function. Replicated bidirectional selection for thermoregulatory nest-building behavior in the laboratory house mouse (Mus musculus) resulted in compulsive-like, non-compulsive-like and randomly bred control mice that represent a non-induced animal model of OCD. The present study aimed at investigating the neurochemical patterns in specific brain regions of compulsive-like (HA) versus non-compulsive-like (LA) and normal (CA) mice. The neurochemical investigation of several brain regions of the corticostriato-thalamocortical circuity, i.e., nucleus caudatus (CPU), nucleus accumbens (NAc), globus pallidus (GP), hippocampus (HPC), amygdala (AM), ventral tegmental area (VTA) and substantia nigra (SN) was performed by electrochemical (serotonin and dopamine) and fluorescence (glutamate and GABA) HPLC detection. HA mice displayed significantly decreased 5-HT concentrations in the mPFC and LA mice displayed a significant increase in GABA concentrations in the mPFC. This supports the pathophysiological relevance of serotonin in the manifestation of OCD and adding to the construct validity of the non-induced mouse model of OCD.

Entrainment of the master circadian clock by scheduled feeding.

The master circadian clock, located in the mammalian suprachiasmatic nuclei (SCN), generates and coordinates circadian rhythmicity, i.e., internal organization of physiological and behavioral rhythms that cycle with a near 24-h period. Light is the most powerful synchronizer of the SCN. Although other nonphotic cues also have the potential to influence the circadian clock, their effects can be masked by photic cues. The purpose of this study was to investigate the ability of scheduled feeding to entrain the SCN in the absence of photic cues in four lines of house mouse (Mus domesticus). Mice were initially housed in 12:12-h light/dark cycle with ad libitum access to food for 6 h during the light period followed by 4-6 mo of constant dark under the same feeding schedule. Wheel running behavior suggested and circadian PER2 protein expression profiles in the SCN confirmed entrainment of the master circadian clock to the onset of food availability in 100% (49/49) of the line 2 mice in contrast to only 4% (1/24) in line 3 mice. Mice from line 1 and line 4 showed intermediate levels of entrainment, 57% (8/14) and 39% (7/18), respectively. The predictability of entrainment vs. nonentrainment in line 2 and line 3 and the novel entrainment process provide a powerful tool with which to further elucidate mechanisms involved in entrainment of the SCN by scheduled feeding.

Diet and mental health in the Arctic: is diet an important risk factor for mental health in circumpolar peoples?--a review.

BACKGROUND: The people living in Arctic and Subarctic environments have adapted to cold temperatures, short growing seasons, and low precipitation, but their traditional ways are now changing due to increased contact with Western society. The rapid alteration of circumpolar cultures has led to generational changes in diet from traditional foods to the processed groceries common in modern stores. OBJECTIVES: Develop a link between changing traditional diets and mental health that may have substantial consequences for circumpolar peoples. METHODS: Review of English language literature pertaining to the northern circumpolar environments of the world that consist of the Arctic and Subarctic areas. Electronic resources such as ISI Web of Science and PubMed were utilized, using keywords such as arctic, circumpolar, diet, omega-3 fatty acids, mental health, seasonal affective disorder, and suicide. In addition, we used the cited references of obtained articles and the extensive University of Alaska Fairbanks library collections to identify additional publications that were not available from the electronic resources. The years covered were not restricted to any particular period, although 83% of the sources were published in the last 16 years. CONCLUSION: The change in traditional diets has already led to increased health problems, such as obesity, cardiovascular disease, and diabetes, while the mental health of circumpolar peoples has also declined substantially during the same time period. The decline in mental health is characterized by increased rates of depression, seasonal affective disorder, anxiety, and suicide, that now often occur at higher rates than in lower-latitude populations. Studies in non-circumpolar peoples have shown that diet can have profound effects on neuronal and brain development, function, and health. Therefore, we hypothesize that diet is an important risk factor for mental health in circumpolar peoples.