Spiraling Dopaminergic Circuitry From the Ventral Striatum to Dorsal Striatum Is an Effective Feed-Forward Loop.
Spiraling Dopaminergic Circuitry From the Ventral Striatum to Dorsal Striatum is an Effective Feed-Forward Loop.
Neuroscience. 2013 Mar 23;
Ikeda H, Saigusa T, Kamei J, Koshikawa N, Cools AR
Central dopamine systems are key players in the cerebral organization of behavior and in various neurological and psychiatric diseases. We demonstrate the presence of a neurochemical feed-forward loop characterized by region-specific changes in dopamine efflux in serially connected striatal regions, providing evidence in favor of the existence of so-called spiraling striato-nigro-striatal connections. Using in vivo microdialysis of rats, we show that simultaneous stimulation of dopamine D1 and D2 receptors in the accumbal shell decreased dorsal striatal dopamine efflux via a direct or indirect feed-forward loop involving shell, core, ventrolateral and dorsal striatum: simultaneous stimulation of dopamine D1 and D2 receptors in the shell decreased dopamine efflux in the core; flupenthixol-induced inhibition of dopamine D1 and D2 receptors in the core increased dopamine efflux in the ventrolateral striatum, and simultaneous stimulation of dopamine D1 and D2 receptors in the ventrolateral striatum decreased dopamine efflux in the dorsal striatum. Finally, simultaneous stimulation of dopamine D1 and D2 receptors in the shell decreased dopamine efflux in the dorsal striatum. Thus, distinct striatal regions act also in series, providing a better understanding of the neural mechanisms underlying dopamine-dependent behaviors and the progression of dopamine-dependent disorders such as depression, schizophrenia, attention deficit hyperactivity disorder, and addiction. HubMed – addiction
Antioxidant food supplements and obesity-related inflammation.
Curr Med Chem. 2013 Mar 15;
Mangge H, Summers K, Almer G, Prassl R, Weghuber D, Schnedl W, Fuchs D
The obesity prevalence is growing worldwide and largely responsible for the increased incidence of cardiovascular disease, the most common cause of death in the western world. Excessive food intake along with insufficient physical exercise is the basic impetus for this development. The obese state is commonly associated with an increase in leptin levels and chronic immune-mediated inflammation. Despite high leptin levels, the leptin response, normally associated with satiety and satiation, seems to be impaired and individuals continue to consume calorie-rich food. Antioxidant food additives such as sodium sulphite, sodium benzoate and curcumin were shown to suppress the leptin release in lipopolysaccharide-treated murine adipocytes. Based on this, we hypothesize that the insufficient leptin release, caused by excessive consumption of food additives, may lead to a reduced exposure of the central nervous system to leptin and ultimately propagate obesity. On the other hand, leptin has been shown to favor Th1-type activity, which ultimately decreases tryptophan levels. Tryptophan derivatives, serotonin and melatonin, induce satiety/satiation through several mechanisms. In this context, the antioxidant suppression of leptin release and Th1-type activity is beneficial to increase serotonin and melatonin levels. The molecules in the mechanism described in this review are highly integrated in the reward system, and have been implicated in the addiction behavior of obesity. Based on these facts, the involvement of antioxidant food supplements in the mechanisms of the reward-deficiency syndrome which perpetuates obesity will be discussed. HubMed – addiction
Mental health differences between frequent cannabis users with and without dependence and the general population.
Addiction. 2013 Mar 27;
van der Pol P, Liebregts N, de Graaf R, Ten Have M, Korf DJ, van den Brink W, van Laar M
AIMS: To compare the prevalence of mental disorders between frequent cannabis users with and without dependence and the general population. DESIGN: Cross-sectional comparison of interview data. SETTING: Enriched community sample of frequent cannabis users and a representative sample of non-users and non-frequent users from the general population. PARTICIPANTS: 521 young adult (18-30 years) frequent cannabis users of whom 252 with DSM-IV cannabis dependence (D+) and 269 without DSM-IV cannabis dependence (D-), and 1,072 young adults from the general population. MEASUREMENTS: Multinomial logistic regression was used to compare groups regarding the presence of DSM-IV mental disorders. Detailed measures of cannabis use, childhood adversity, and other substance use were considered confounders. FINDINGS: Compared with the general population, externalising disorders were more prevalent in D- (OR=8.91, p<0.001) and most prevalent in D+ (OR=17.75, p<0.001), but internalising disorders were associated only with D+ (mood OR=4.15, p<0.001; anxiety OR=2.20, p=0.002). Associations were attenuated (and often became non-significant) after correction for childhood adversity and substance use other than cannabis. However, the prevalence of mental disorders remained higher in D+ compared with D- (OR=2.40, p<0.001) although cannabis use patterns were remarkably similar. CONCLUSIONS: Cannabis use patterns, childhood adversity and the use of other substances are similar in dependent and non-dependent frequent cannabis users. With the exception of more externalising disorders, the mental health condition of non-dependent frequent cannabis users is similar to that of the general population, whereas it is worse in dependent frequent cannabis users. HubMed – addiction
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