Background: We used a validated inpatient satisfaction questionnaire to evaluate the health care received by patients admitted to several hospitals. This questionnaire was factored into distinct domains, creating a score for each to assist in the analysis.
Background Alcohol increases the expression of Group 1 metabotropic glutamate receptors (mGluRs), their associated scaffolding protein Homer2, and stimulates phosphatidylinositol 3-kinase (PI3K) within the nucleus accumbens (NAC). Moreover, functional studies suggest that NAC Group 1 mGluR/Homer2/PI3K signaling may be a potential target for pharmacotherapeutic intervention in alcoholism. Methods Immunoblotting was conducted to examine the effects of alcohol consumption under Drinking-in-the-Dark (DID) procedures on Group 1 mGluR-associated proteins in C57BL/6J (B6) mice. Follow-up behavioral studies examined the importance of Group 1 mGluR/Homer2/PI3K signaling within the NAC shell for limited access alcohol drinking. Finally, immunoblotting examined whether the NAC expression of Group 1 mGluR-associated proteins is a genetic correlate of high alcohol drinking using a selectively bred high DID (HDID-1) mouse line. Results Limited access alcohol drinking under DID procedures up-regulated NAC shell Homer2 levels, concomitant with increases in mGluR5 and NR2B. Intra-NAC shell blockade of mGluR5, Homer2, or PI3K signaling, as well as transgenic disruption of the Homer binding site on mGluR5 decreased alcohol consumption in B6 mice. Moreover, transgenic disruption of the Homer binding site on mGluR5 and Homer2 deletion both prevented the attenuating effect of mGluR5 and PI3K blockade upon intake. Finally, the basal NAC shell protein expression of mGluR1 and Homer2 was increased in offspring of HDID-1 animals. Conclusions Taken together, these data further implicate Group1 mGluR signaling through Homer2 within the NAC in excessive alcohol consumption.
Despite the fact that binge alcohol drinking (intake resulting in blood alcohol concentrations (BACs) X80 mg% within a 2-h period) is the most prevalent form of alcohol-use disorders (AUD), a large knowledge gap exists regarding how this form of AUD influences neural circuits mediating alcohol reinforcement. The present study employed integrative approaches to examine the functional relevance of binge drinking-induced changes in glutamate receptors, their associated scaffolding proteins and certain signaling molecules within the central nucleus of the amygdala (CeA). A 30-day history of binge alcohol drinking (for example, 4-5 g kg) elevated CeA levels of mGluR1, GluN2B, Homer2a/b and phospholipase C (PLC) b3, without significantly altering protein expression within the adjacent basolateral amygdala. An intra-CeA infusion of mGluR1, mGluR5 and PLC inhibitors all dose-dependently reduced binge intake, without influencing sucrose drinking. The effects of co-infusing mGluR1 and PLC inhibitors were additive, whereas those of coinhibiting mGluR5 and PLC were not, indicating that the efficacy of mGluR1 blockade to lower binge intake involves a pathway independent of PLC activation. The efficacy of mGluR1, mGluR5 and PLC inhibitors to reduce binge intake depended upon intact Homer2 expression as revealed through neuropharmacological studies of Homer2 null mutant mice. Collectively, these data indicate binge alcohol-induced increases in Group1 mGluR signaling within the CeA as a neuroadaptation maintaining excessive alcohol intake, which may contribute to the propensity to binge drink.
Background The high prevalence and severity of methamphetamine (MA) abuse demands greater neurobiological understanding of its etiology. Methods Here, we conducted immunoblotting and in vivo microdialysis procedures in Methamphetamine High/Low Drinking (MAH/LDR) mice, as well as in isogenic C57BL/6J mice that varied in their MA-preference/taking, to examine the glutamate underpinnings of MA abuse vulnerability. Neuropharmacological and Homer2 knock-down approaches were also employed in C57BL/6J mice to confirm the role for nucleus accumbens glutamate/Homer2 expression in MA preference/aversion. Results We identified a hyper-glutamatergic state within the nucleus accumbens (NAC) as a biochemical trait corresponding with both genetic and idiopathic vulnerability for high MA-preference and -taking. We also confirmed that subchronic, subtoxic MA experience elicits a hyper-glutamatergic state within the NAC during protracted withdrawal, characterized by elevated mGlu1/5 receptor function and Homer2 receptor-scaffolding protein expression. A high MA-preferring phenotype was recapitulated by elevating endogenous glutamate within the NAC shell of mice and we reversed MA-preference/taking by lowering endogenous glutamate and/or Homer2 expression within this subregion. Conclusions Our data point to an idiopathic, genetic or drug-induced hyper-glutamatergic state within the NAC as a mediator of MA addiction vulnerability.
Online microdialysis is a sampling and detection method that enables continuous interrogation of extracellular molecules in freely moving subjects under behaviorally relevant conditions. A majority of recent publications using brain microdialysis in rodents report sample collection times of 20−30 min. These long sampling times are due, in part, to limitations in the detection sensitivity of high performance liquid chromatography (HPLC). By optimizing separation and detection conditions, we decreased the retention time of serotonin to 2.5 min and the detection threshold to 0.8 fmol. Sampling times were consequently reduced from 20 to 3 min per sample for online detection of serotonin (and dopamine) in brain dialysates using a commercial HPLC system. We developed a strategy to collect and to analyze dialysate samples continuously from two animals in tandem using the same instrument. Improvements in temporal resolution enabled elucidation of rapid changes in extracellular serotonin levels associated with mild stress and circadian rhythms. These dynamics would be difficult or impossible to differentiate using conventional microdialysis sampling rates.
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