Both hypoactivity and hyperactivity in the amygdala are associated with perturbations in social behavior. While Ͼ60 years of experimental manipulations of the amygdala in animal models have shown that amygdala is critical for social behavior, many of these studies contradict one another. Moreover, several questions remain unaddressed. (1) What effect does activation of amygdala have on social behavior? (2) What is the effect of transient silencing, rather than permanent damage? (3) Is there a dissociation between the roles of the central (CeA) and basolateral amygdala (BLA) in regulating social behavior? (4) Can the prosocial effects of amygdala manipulations be explained by anxiolytic effects? We focally manipulated activity within the CeA or BLA in macaques by intracerebral microinjection of muscimol (to inactivate) or bicuculline (to activate) to these amygdaloid subregions. Social interactions were observed in pairs of highly familiar monkeys. We compared these effects to those achieved with systemic diazepam. Activation of the BLA but not CeA suppressed social behavior. Inhibition of either structure increased social behavior, although the effect was greater following inhibition of the BLA. Systemic diazepam was without effect. These studies, which are the first to bidirectionally manipulate the primate amygdala for effects on social behavior, revealed that (1) the amygdala, as a critical regulator of the social network, is bidirectionally sensitive to perturbations in activity, and (2) increased sociability after amygdala inactivation cannot be solely explained by decreased fear.

Background: Axonal transport deficits are part of Alzheimer disease (AD) pathobiology. Results: ␤-Amyloid (A␤) impairs BDNF-dependent retrograde signaling, which is rescued by increasing cellular UCH-L1 levels. Conclusion: In AD, A␤ impairs neurotrophin-mediated retrograde signaling by disrupting ubiquitin homeostasis. Significance: Elucidating the mechanism by which A␤ causes transport deficits that compromise synaptic plasticity and neuronal survival is crucial for discovering novel therapeutics to reverse cognitive deficits in AD.

The a3b4 nicotinic acetylcholine receptor (nAChR) subtype is widely expressed in the peripheral and central nervous systems, including in airway sensory nerves. The nAChR subtype transduces the irritant effects of nicotine in tobacco smoke and, in certain brain areas, may be involved in nicotine addiction and/or withdrawal. Menthol, a widely used additive in cigarettes, is a potential analgesic and/or counterirritant at sensory nerves and may also influence nicotine's actions in the brain. We examined menthol's effects on recombinant human a3b4 nAChRs and native nAChRs in mouse sensory neurons. Menthol markedly decreased nAChR activity as assessed by Ca 21 imaging, 86 Rb 1 efflux, and voltage-clamp measurements. Coapplication of menthol with acetylcholine or nicotine increased desensitization, demonstrated by an increase in the rate and magnitude of the current decay and a reduction of the current integral. These effects increased with agonist concentration. Pretreatment with menthol followed by its washout did not affect agonist-induced desensitization, suggesting that menthol must be present during the application of agonist to augment desensitization. Notably, menthol acted in a voltageindependent manner and reduced the mean open time of single channels without affecting their conductance, arguing against a simple channel-blocking effect. Further, menthol slowed or prevented the recovery of nAChRs from desensitization, indicating that it probably stabilizes a desensitized state. Moreover, menthol at concentrations up to 1 mM did not compete for the orthosteric nAChR binding site labeled by [ 3 H]epibatidine. Taken together, these data indicate that menthol promotes desensitization of a3b4 nAChRs by an allosteric action.

Coastal habitat contamination with Toxoplasma gondii is a health risk to humans and marine wildlife, with infections documented in both nearshore and pelagic marine mammals. Due to lack of sensitive methods for detection of T. gondii in water, this study utilized an alternative surveillance approach for evaluating marine habitat contamination using wild mussels. The objectives of this study were to (i) validate sensitive molecular tools for T. gondii detection in mussels and (ii) apply optimized methods in a surveillance study to determine the prevalence and genotype(s) of T. gondii in mussels. Simplex polymerase chain reaction screening and multiplex genotyping assays were validated and then applied on 959 wild-caught mussels collected from central California. Thirteen mussels (1.4%) had detectable T. gondii DNA and the presence of T. gondii in mussels was significantly associated with proximity to freshwater run-off and collection during the wet season. Molecular characterization revealed alleles from T. gondii types I, II/III, X at the B1 locus, and a novel atypical B1 allele that was recently documented in T. gondii-infected carnivores from California. Findings demonstrate higher than previously reported T. gondii contamination of California coastlines, and describe novel strains of the parasite that further link terrestrial sources with marine contamination.

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