The COMT Val158Met polymorphism has been associated with anxiety and affective disorders, but its effect on anxiety-related personality traits varies between studies. Our purpose was to investigate the effect of COMT Val158Met on personality traits from adolescence to young adulthood in a population representative Caucasian birth cohort. Also its association with educational attainment and anxiety and mood disorders by the age 25 were examined. This analysis is based on the older cohort of the Estonian Children Personality Behavior and Health Study (original number of subjects 593). The personality traits were assessed when the participants were 15, 18 and 25 years old. COMT Val158Met had an effect on Neuroticism in females by age 25 (p = 0.001, Bonferroni-corrected for five traits), whereas female Val homozygotes scored the highest. In addition, the Conscientiousness scores of subjects with Val/Val genotype were decreasing in time, being the lowest by the age 25 (p = 0.006, Bonferroni-corrected for five traits). By the age 25, males with the Val/Met genotype had mainly secondary or vocational education, whereas female heterozygotes mostly had obtained or were obtaining university education. COMT Val158Met was not associated with anxiety or mood disorders in either gender. These results suggest that genes affecting dopamine system are involved in the development of personality traits and contribute to educational attainment.

From birth to slaughter, pigs are in constant interaction with microorganisms. Exposure of the skin, gastrointestinal and respiratory tracts, and other systems allows microorganisms to affect the developmental trajectory and function of porcine physiology as well as impact behavior. These routes of communication are bi-directional, allowing the swine host to likewise influence microbial survival, function and community composition. Microbial endocrinology is the study of the bi-directional dialogue between host and microbe. Indeed, the landmark discovery of host neuroendocrine systems as hubs of host–microbe communication revealed neurochemicals act as an inter-kingdom evolutionary-based language between microorganism and host. Several such neurochemicals are stress catecholamines, which have been shown to drastically increase host susceptibility to infection and augment virulence of important swine pathogens, including Clostridium perfringens. Catecholamines, the production of which increase in response to stress, reach the epithelium of multiple tissues, including the gastrointestinal tract and lung, where they initiate diverse responses by members of the microbiome as well as transient microorganisms, including pathogens and opportunistic pathogens. Multiple laboratories have confirmed the evolutionary role of microbial endocrinology in infectious disease pathogenesis extending from animals to even plants. More recent investigations have now shown that microbial endocrinology also plays a role in animal behavior through the microbiota–gut–brain axis. As stress and disease are ever-present, intersecting concerns during each stage of swine production, novel strategies utilizing a microbial endocrinology-based approach will likely prove invaluable to the swine industry.

Background: Secondary neurotransmitter deficiencies have been reported in several reviews. Our primary aim was to assess the relationship among epilepsy, antiseizure medications, and specific neurotransmitter abnormalities. We also evaluated movement disorders and brain abnormalities via magnetic resonance imaging scans in patients with secondary neurotransmitter defects. Methods: This is a retrospective case series of 376 patients who underwent neurotransmitter analysis at BC Children’s Hospital between 2009 and 2013, for a variety of neurological presentations. The biochemical genetics laboratory database was interrogated for results of cerebrospinal fluid neurotransmitter analyses. Clinical data for patients with abnormal results were collected from the hospital charts. Statistical analysis included one-way analysis of variance, chi-square, and a two-way contingency table. Results: Abnormal neurotransmitter values were identified in 67 (17.8%) patients, two (0.53%) of which were attributable to a congenital neurotransmitter disorder and 11 (16.9%) secondary to other genetic diagnoses. Of 64 patients with secondary abnormal neurotransmitter values, 38 (59%) presented with epilepsy and 20 (31%) with movement disorders. A combination of epilepsy and movement disorder was less frequent. Discussion: Acknowledging the limitations of this retrospective chart review, we conclude that, in our cohort, in addition to patients with movement disorders, a considerable number of patients with epilepsy and epileptic encephalopathy also showed secondary neurotransmitter mono-amine abnormalities. There is no clear relation, however, between clinical phenotype and type of neurotransmitter affected. In addition, no association was identified between the type of antiseizure medications and affected neurotransmitter type. We outline the need for prospective studies to further enrich our understanding of the relation between epilepsy and neurotransmitters with a focus on improving treatments and patient outcomes.

In this review the most important hypotheses for the occurrence of the clinical picture of hepatic encephalopathy are discussed. As possible pathogenetic mechanisms are raised: dysfunction of the serotonergic system due to an increased tryptophan uptake in the brain, an elevated intracerebral ammoniac concentration and glutamine synthesis, and a heightened intracerebral GABA-activity.

The dysregulation of the serotonergic system as a consequence of the increased intracerebral tryptophan uptake is described as one of the most important pathogenetic mechanisms. The elevated intracerebral ammoniac concentration and the elevated intracerebral glutamine synthesis play in this a facilitating role. The similarity in symptomatology of the clinical picture of HE and the serotonergic syndrome support this hypothesis. Due to contradictory research findings the role of the GABA-ergic system and the occurrence of HE remains unclear.

The purpose of this article is to give a comprehensive review of biological theories about the development of panic disorder.

Noradrenergic, serotonergic and GABA-ergic models of panic disorder are discussed, together with the role of peptides and neuroanatomical hypotheses.

The conclusion is that there is no unitary biological explanation of panic disorder.

An intergrative bio-psycho-social model seems for the moment the most usefull.

Aggression is a behavior with evolutionary origins, but is often both destructive and maladaptive in today’s society. Research over the past several decades has confirmed the involvement of neurotransmitter function in aggressive behavior. This research has centered around the “serotonin hypothesis.” As this literature continues to grow, guided by pre-clinical research and aided by the application of increasingly sophisticated neuroimaging methodology, a more complex picture has emerged. As current pharmacological and therapeutic interventions are effective but imperfect, it is hoped that new insights into the neurobiology of aggression will reveal novel avenues for treatment of this destructive and costly behavior.

Social anxiety disorder (SAD) is a condition characterized by pervasiveness and impairment in social functioning, with a prevalence in the general population between 1.9% and 12.1%. The most consistent findings on its neurobiological underpinnings involve a wide range of neurotransmitters (serotonin, norepinephrine, glutamate, and GABA) and neuropeptides (oxytocin), but no comprehensive hypothesis is yet available. In particular, oxytocin is becoming increasingly established as a “prosocial neuropeptide” and, as such, is a major focus of current research, with a great range of therapeutic applications including SAD treatment. Specifically, the amygdala plays a pivotal role in conditioning and processing of fear, and exaggerated amygdala responses in SAD patients have been observed during various social-emotional stimuli. In addition to the amygdala, other brain areas of interest in SAD-related circuitry are represented by the medial prefrontal cortex, dorsal raphe, striatum, locus coeruleus, prefrontal cortex, insular cortex, and anterior cingulate cortex. The aim of this review is to provide an update on neurobiological correlates of SAD, with a special focus on neurotransmitters and brain areas possibly involved, and suggestions for future research that could lead to more specific therapeutic interventions.

Immunohistochemical techiniques were used to survey the distribution of several conventional transmitters, receptors, and neuropeptides in the pigeon nucleus of the basal optic root (nBOR), a component of the accessory optic ststem. Amongst the conventional neurotransmitts'modulators, the most intense labeling of fibers/terminals within the nBOR was obtained with antisera directed against glutamic acid decarboxylase (GAD) and serotonin (5-HT). Moderately dense fiber plexuses were seen to label with antibodies directed against tyrosine hydroxylase (TH) and choline acetltransferase (ChAT). GAD-like immunoractivity (GAD-L1) was found in many small and medium-size perikarya within the nBOR. Some of the medium-sized cells were occasionally positive for ChAT-L1. Cell body and dendritic staining was also commonly seen with the two tested antisera against receptors–anti-GABA-A receptor and anti-nicotinic acetylcholine receptor.

The antisera directed against various neuropetides produced only fiber labelling within the nBOR. The densest fiber plexus staining was observed with antiserum against neuropeptide Y (NPY-L1), while intermediate fiber densities were seen for substance P (SP-L1) and cholecystokinin (CCK-L1). A few varicose fibers were labeled with antisera against neurotensin (NT), leucine-enkephalin (L-KNK), and the vasoactive intestinal polypeptide (VIP).

Unilateral enucleation produced an almost complete elimination of TH-L1 in the contralateral nBOR. SP-L1 and CCK-L1 were also decreased after enucleation. No apparent changes were seen for all other substances.

These results indicate that a wide variety of chemically-specific systems arborize within the nBOR. Three of the immunohistochemically defined fiber systems (TH-LI, SP-LI, and CCK-LI fibers) were reduced after removal of the retina, which may indicate the presence of these substances in retinal ganglion cells. In contrast, the fibers exhibiting ChAT-LI, GAD-LI, 5-HT-Ll, NPY-Ll, NT-LI, L-ENK-LI, and VIP-LI appear to be of nonretinal origin. Two different populations of nBOR neurons exhibited GAD-LI and ChAT-LI. However, these two populations together constituted only about 20% of the nBOR neurons.

Postembedding immunocytochemistry was used to determine the retinal distribution of the amino acid glutamine, and characterize amino acid signatures in the avian retinal ganglion cell layer. Glutamine is a potential precursor of glutamate and some glutamatergic neurons may use this amino acid to sustain production of glutamate for neurotransmission. Ganglion cells, cells in the inner nuclear layer, and some photoreceptors exhibited glutamine immunoreactivity of varying intensity. Ganglion cells demonstrated the highest level of immunoreactivity which indicates either slow glutamine turnover or active maintenance of a large standing glutamine pool relative to other glutamatergic neurons. Müller's cells in the avian retina are involved in glutamate uptake and carbon recycling by the rapid conversion of glutamate to glutamine, thus explaining the low glutamate and high glutamine immunoreactivity found throughout Müller's cells. Most chicken retinal ganglion cells are glutamate (E) and glutamine (Q) immunoreactive but display diverse signatures with presumed functional subsets of cells displaying admixtures of E and Q with GABA (7) and/or glycine (G). The four major ganglion cell signatures are (1) EQ; (2) EQγ; (3) EQG; and (4) EQγG.

A small number of enkephalin-like immunoreactive cells were observed in the ganglion cell layer of the pigeon retina. Many of these neurons were identified as ganglion cells, since they were retrogradely labeled after injections of fluorescent latex microspheres in the contralateral optic tectum. These ganglion cells were mainly distributed in the inferior retina, and their soma sizes ranged from 12–26 μm in the largest axis. The enkephalin-containing ganglion cells appear to represent only a very small percentage of the ganglion cells projecting to the optic tectum (less than 0.1%). Two to 7 weeks after removal of the neural retina, there was an almost complete elimination of an enkephalin-like immunoreactive plexus in layer 3 of the contralateral, rostrodorsal optic tectum. These data provide evidence for the existence of a population of enkephalinergic retinal ganglion cells with projections to the optic tectum.

Different techniques were used to manipulate the inhibitory interaction between the red and green photoreceptors (R and G cones) of rhesus and human primates. The response techniques that were used were the corneal electroretinogram (ERG) and psychophysical increment-threshold spectral sensitivity functions. Red-green opponency, as measured by the depth of the notch at 580 nm, is removed by intravitreal injection of bicuculline but not by strychnine. Therefore, red-green opponency is mediated by GABA and not glycine. The depth of the notch is dependent upon stimulus size. Between 30' and 15' test light diameters, this sign of red-green opponency disappears. Psychophysical increment thresholds are shown to produce the notch while decrements do not and intravitreal APB is shown to reduce the notch, evidence that red-green opponency is carried by the “ON” and not the “OFF” bipolar pathways of the retina. Red and green annuli are shown to selectively reduce red and green inhibition, as though there were selective reduction of the surround response in center-surround organized red-green receptive fields.