Alpha-synuclein (alpha-syn) is implicated in the pathogenesis of Parkinson's disease (PD). Mutations in alpha-syn gene or alpha-syn locus (SNCA) triplication are associated with mitochondrial abnormalities and early onset of familial PD. The goals of the present study were to examine whether alpha-syn is localized in the mitochondria of alpha-syn overexpressing cells (HEK-syn cells); and whether alpha-syn overexpression causes cells to be more vulnerable to mitochondrial toxin, rotenone. Western blotting and confocal microscopy techniques were employed to assess localization of alpha-syn in the mitochondria of HEK-293 cells that were stably transfected with human wild-type alpha-syn. The results demonstrated that the mitochondrial fractions that were isolated from HEK-syn cells showed the presence of alpha-syn, whereas, no alpha-syn was detected in the mitochondrial fractions of control HEK cells. The mitochondria of HEK-syn cells were found to be more susceptible to rotenone-induced toxicity when compared to control HEK cells. The intracellular ATP levels were significantly decreased in HEK-syn cells in response to sub toxic concentrations of rotenone. These results suggest that under overexpression conditions, alpha-syn may translocate to mitochondria and cause enhanced toxicity in response to sub toxic concentrations of mitochondrial toxins. This study has implications to the pathogenesis of familial PD where alpha-syn overexpression is mainly involved.

Rhodopsin receptor activation involves the disruption of a salt bridge constraint between glutamic acid 113 on transmembrane 3 and a lysine 296 in transmembrane 7, which forms a Schiff's base with retinal. Lightinduced isomerization of cis-retinal to the all trans form breaks this rhodopsin salt bridge leading to receptor activation. The analogous residues in ␣ 1b -adrenergic receptors, aspartic acid 125 and lysine 331, also have the potential of forming a constraining salt bridge holding the receptor to an inactive protein configuration. This ␣ 1b -adrenergic receptor salt bridge constraint is then released upon binding by the receptor agonist. To test this hypothesis, site-directed mutagenesis was used to eliminate the positive charge at position 331 by substitution of an alanine. The expressed ␣ 1b -adrenergic receptor mutant demonstrated a 6-fold increased epinephrine binding affinity with no alterations of affinity values for selective adrenergic receptor antagonists. Furthermore, an increased epinephrine potency for total soluble inositol phosphate production along with an elevated basal inositol triphosphate level was observed in COS-1 cells transfected with mutant versus wild-type ␣ 1b -adrenergic receptors. Similar results were obtained for a lysine to a glutamic acid ␣ 1b -adrenergic receptor mutation. In addition, increased basal inositol triphosphate levels were also observed for two aspartic acid 125 ␣ 1b -adrenergic receptor mutations, consistent with this residue's role as the counterion of the salt bridge. Taken together, these ␣ 1b -adrenergic receptor mutations suggest a molecular mechanism by which the positively charged lysine 331 stabilizes the negatively charged aspartic acid 125 via a salt bridge constraint until bound by the receptor agonist.

Summary The entorhinal cortex (EC) is regarded as the gateway to the hippocampus and thus is essential for learning and memory. Whereas the EC expresses a high density of GABAB receptors, the functions of these receptors in this region remain unexplored. Here we examined the effects of GABAB receptor activation on neuronal excitability in the EC and spatial learning. Application of baclofen, a specific GABAB receptor agonist, inhibited significantly neuronal excitability in the EC. GABAB receptor-mediated inhibition in the EC was mediated via activating TREK-2, a type of two-pore domain K+ channels and required the functions of inhibitory G proteins and protein kinase A pathway. Depression of neuronal excitability in the EC underlies GABAB receptor-mediated inhibition of spatial learning as assessed by Morris water maze. Our study indicates that GABAB receptors exert a tight control over spatial learning by modulating neuronal excitability in the EC.

Catecholamines released from the sympathetic nervous system in response to stress or injury affect expression of inflammatory cytokines generated by immune cells. ␣ 1 -Adrenergic receptors (ARs) are expressed on innate immune cell populations, but their subtype expression patterns and signaling characteristics are not well characterized. Primary human monocytes, a human monocytic cell line, and monocyte-derived macrophage cells were used to measure expression of the proinflammatory mediator interleukin (IL)-1␤ responding to lipopolysaccharide (LPS) in the presence or absence of ␣ 1 -AR activation. Based on our previous findings, we hypothesized that ␣ 1 -AR stimulation on innate immune cells positively regulates LPS-initiated IL-1␤ production. IL-1␤ production in response to LPS was synergistically higher for both monocytes and macrophages in the presence of the selective ␣ 1 -AR agonist (R)-(Ϫ)-phenylephrine hydrochloride (PE). This synergistic IL-1␤ response could be blocked with a selective ␣ 1 -AR antagonist as well as inhibitors of protein kinase C (PKC). Radioligand binding studies characterized a homogenous ␣ 1B -AR subtype population on monocytes, which changed to a heterogeneous receptor subtype expression pattern when differentiated to macrophages. Furthermore, increased p38 mitogenactivated protein kinase (MAPK) activation was observed only with concurrent PE and LPS stimulation, peaking after 120 and 30 min in monocytes and macrophages, respectively. Blocking the PKC/p38 MAPK signaling pathway in both innate immune cell types inhibited the synergistic IL-1␤ increase observed with concurrent PE and LPS treatments. This study characterizes ␣ 1 -AR subtype expression on both human monocyte and macrophage cells and illustrates a mechanism by which increased IL-1␤ production can be modulated by ␣ 1 -AR input.

Although anorexia nervosa typically begins during adolescence with proneness to the disorder beginning even earlier, reliability and normative studies of the Eating Disorder Inventory (EDI) have relied primarily on college‐aged students. This problem was addressed by examining subscale performance of a normative sample of 619 boys and girls from 11 to 18 years of age who attended public school in Ontario, Canada. Analyses of the internal consistency of the EDI subscales Bulimia and Maturity Fears failed to demonstrate adequate reliability for either boys or girls. Perfectionism and Interpersonal Distrust subscales were also unreliable for the boys. Analysis of variance procedures revealed that girls scored higher than boys on Drive for Thinness, Body Dissatisfaction, and Interoceptive awareness. Older (14–18 years) girls differed from younger (11–13 years) girls, scoring higher on Body Dissatisfaction and lower on Interpersonal Distrust. Older and younger boys did not differ from each other on any of the EDI subscales, nor did they differ from the 14–18‐year‐old norms presented by Rosen, Silberg, and Gross (1988). Older girls, on the other hand, scored higher than the Rosen et al. norms on Drive for Thinness and Interoceptive Awareness. EDI percentile scores are presented for girls 11–13 and 14–18 years of age.