Gabaergic mechanisms and anxiety: an overview and a new neurophysiological model

Infra-Low Frequency Neurofeedback rapidly ameliorates schizophrenia symptoms: A case report of the first session

A 38-year-old army officer started therapy in 2020 with a four-year history of auditory hallucinations and delusions of reference, persecution and grandeur, symptoms that were resistant to traditional antipsychotic medications. He follows an integrative psychotherapy program that aims to reduce his anxiety, continues his antipsychotic medications, and has Infra-Low Frequency Neurofeedback. After his initial assessment he had a 40 min session of Infra-Low Frequency Neurofeedback before any other kind of intervention. Before and immediately after the session he completed the SCL-90 scale and the Visual Analog Scale covering 20 aspects of his psychological and physical state as well as his schizophrenic symptoms. This first Neurofeedback session had dramatic effects on his psychotic symptoms, levels of anxiety and psychosomatic condition, before his first psychotherapy session and/or any changes in his antipsychotic medication. The above results have great importance due to the severity and chronicity of schizophrenia. Informed consent was obtained from the participant for the publication of this case report (including all data and images).

Compositional Features and Codon Usage Pattern of Genes Associated with Anxiety in Human

Codon usage bias (CUB) is the unequal usage of synonymous codon; some codons are more preferred than others. CUB analysis has applications in understanding the molecular organization of genome, genetics, gene expression, and molecular evolution. Bioinformatic approach was used to analyze the protein-coding sequences of genes involved in the anxiety to understand the patterns of codon usage as no work was reported yet. The improved effective number of codons (Nc) values ranged from 43.55 to 55.06, with a mean of 44.57, suggested that the overall CUB was low for genes associated with anxiety. The overall GC and AT content was 54.76 and 45.24, respectively. Relative synonymous codon usage (RSCU) analysis revealed that most frequently used codon ended mostly with C or G. The over-represented codons in genes associated with anxiety were CTG, ATC, GTG, AGC, ACC, and GCC, while under-represented codons were TTA, CTT, CTA, ATA, GTT, GTA, TCG, CCG, GCG, CAA, and CGT. Correlation analysis was performed between overall nucleotide composition and its 3rd codon positions, and observed highly significant (p < 0.01) correlation between them suggested that both mutation pressure and natural selection might affect the pattern of CUB. The highly significant correlation (0.598**, p < 0.01) was also observed between GC12 with GC3 suggested that directional mutation pressure might acted on all codon positions for genes associated with anxiety.

CO2-induced ocean acidification does not affect individual or group behaviour in a temperate damselfish

Open ocean surface CO₂ levels are projected to reach approximately 800 µatm, and ocean pH to decrease by approximately 0.3 units by the year 2100 due to anthropogenic CO₂ emissions and the subsequent process of ocean acidification (OA). When exposed to these CO₂/pH values, several fish species display abnormal behaviour in laboratory tests, an effect proposed to be linked to altered neuronal GABA_A- receptor function. Juvenile blacksmith (Chromis punctipinnis) are social fish that regularly experience CO₂/pH fluctuations through kelp forest diurnal primary production and upwelling events, so we hypothesized that they might be resilient to OA. Blacksmiths were exposed to control conditions (pH ∼ 7.92; pCO₂ ∼ 540 µatm), constant acidification (pH ∼ 7.71; pCO₂ ∼ 921 µatm) and oscillating acidification (pH ∼ 7.91, pCO₂ ∼ 560 µatm (day), pH ∼ 7.70, pCO₂ ∼ 955 µatm (night)), and caught and tested in two seasons of the year when the ocean temperature was different: winter (16.5 ± 0.1°C) and summer (23.1 ± 0.1°C). Neither constant nor oscillating CO₂-induced acidification affected blacksmith individual light/dark preference, inter-individual distance in a shoal or the shoal's response to a novel object, suggesting that blacksmiths are tolerant to projected future OA conditions. However, blacksmiths tested during the winter demonstrated significantly higher dark preference in the individual light/dark preference test, thus confirming season and/or water temperature as relevant factors to consider in behavioural tests.

Neurotransmitter-mediated action of an antagonist of growth hormone-releasing hormone on anxiolysis in mice

Antagonists of growth hormone-releasing hormone (GH-RH), such as MZ-4-71 suppress the secretion of GH. These findings suggest that GH-RH antagonists could be used for the therapy of disorders characterized by excessive GH secretion. It has been also demonstrated that MZ-4-71 displays antidepressant effects in a modified forced swimming test in mice, exerts anxiolytic effects in an elevated plus maze test, improves memory consolidation in passive avoidance learning, and corrects the impairment of memory consolidation caused by β-amyloid (25-35) in mice. However, little is known about the mechanisms of action of MZ-4-71 on brain functions. In the present work, the involvement of the adrenergic, serotonergic and GABA-ergic receptors in the anxiolytic action of MZ-4-71 was studied in an elevated plus maze. Mice were pretreated with a nonselective α-adrenergic receptor antagonist, phenoxybenzamine, an α1/α2β-adrenergic receptor antagonist, prazosin, an α2-adrenergic receptor antagonist, yohimbine, a mixed 5-HT1/5-HT2 serotonergic receptor antagonist, methysergide, a non-selective 5-HT2 serotonergic receptor antagonist, cyproheptadine, and a γ-aminobutyric acid subunit (GABA-A) receptor antagonist, bicuculline. Phenoxybenzamine, prazosin, yohimbine, methysergide, cyproheptadine and bicuculline prevented the effects of MZ-4-71 on the elevated plus maze revealing that the anxiolytic actions of MZ-4-71 in this test are mediated, at least in part, by the an interaction of the α1/α2-adrenergic, 5-HT1/5-HT2 serotonergic and GABA-A-ergic receptors.

Reconciling the role of central serotonin neurons in human and animal behavior

Animal research suggests that central serotonergic neurons are involved in behavioral suppression, particularly anxiety-related inhibition. The hypothesis linking decreased serotonin transmission to reduced anxiety as the mechanism in the anxiolytic activity of benzodiazepines conflicts with most clinical observations. Serotonin antagonists show no marked capacity to alleviate anxiety. On the other hand, clinical signs of reduced serotonergic transmission (low 5-HIAA levels in the cerebrospinal fluid) are frequently associated with aggressiveness, suicide attempts, and increased anxiety. The target article attempts to reconcile such human and animal findings by investigating whether anxiety reduction or increased impulsivity is more Likely to account for animal behavioral changes associated with decreased serotonergic transmission. The effects of manipulating central serotonin in experimental anxiety paradigms in animals (punishment, extinction, novelty) are reviewed and compared with the effects of antianxiety drugs. Anxiety seems neither necessary nor sufficient to induce control by serotonergic neurons on behavior. Further evidence suggests that behavioral effects of anxiolytics thought to be mediated by decreases in anxiety are not caused by the ability of these drugs to reduce serotonin transmission. Blockade of serotonin transmission, especially at the level of the substantia nigra, results in a shift of behavior toward facilitation of responding. This behavioral shift is particularly marked when there is competition between acting and restraining response tendencies and when obstacles prevent the immediate attainment of an anticipated reward. It is proposed that serotonergic neurons are involved not only in behavioral arousal but also in enabling the organism to arrange or tolerate delay before acting. Decreases in serotonin transmission seem to be associated with the increased performance of behaviors that are usually suppressed, though not necessarily because of the alleviation of anxiety, which might contribute to the suppression.

Acid sensing ion channel (ASIC) inhibitors exhibit anxiolytic-like activity in preclinical pharmacological models

RATIONALE

Acid sensing ion channels (ASICs) are proton-gated ion channels located in the central and peripheral nervous systems. Of particular interest is ASIC1a, which is located in areas associated with fear and anxiety behaviors. Recent reports suggest a role for ASIC1a in preclinical models of fear conditioning and anxiety.

OBJECTIVES

The present experiments evaluated various ASIC inhibitors in preclinical models of autonomic and behavioral parameters of anxiety. In addition, neurochemical studies evaluated the effects of an ASIC inhibitor (A-317567) on neurotransmitter levels in the amygdala.

RESULTS

In electrophysiological studies using hippocampal primary neuronal cultures, three ASIC inhibitors (PcTX-1, A-317567, and amiloride) produced concentration-dependent inhibition of acid-evoked currents. In the stress-induced hyperthermia model, acute administration of psalmotoxin 1 (PcTX-1; 10-56 ng, i.c.v.), A-317567 (0.1-1.0 mg/kg, i.p.), and amiloride (10-100 mg/kg, i.p.) prevented stress-induced elevations in core body temperature. In the four-plate test, acute treatment with PcTX-1 (10-56 ng, i.c.v.) and A-317567 (0.01-0.1 mg/kg, i.p.), but not amiloride (3-100 mg/kg, i.p.), produced dose-dependent and significant increases in the number of punished crossings relative to vehicle-treated animals. Additionally, PcTX-1 (56-178 ng, i.c.v.), A-317567 (0.1-10 mg/kg, i.p.), and amiloride (10-100 mg/kg, i.p.) lacked significant anxiolytic-like activity in the elevated zero maze. In neurochemical studies, an infusion of A-317567 (100 microM) into the amygdala significantly elevated the extracellular levels of GABA, but not glutamate, in this brain region.

CONCLUSIONS

These findings demonstrate that ASIC inhibition produces anxiolytic-like effects in some behavioral models and indicate a potential role for GABAergic mechanisms to underlie these anxiolytic-like effects.

What kind of research can we realistically expect from the practitioner?

This article attempts to revitalize the scientist-practitioner model of psychotherapy by focusing on the research component of the model. Specifically, it takes a realistic look at the types of research that can be conducted by clinicians in an effort to motivate them to engage regularly in clinical research. Towards this end, five experienced scientist-practitioners explore the advantages, disadvantages, and potential of practitioner-initiated research. The problems and solutions for such research are discussed, and recommendations are offered.

Motor, but not sensory, cortical potentials are amplified by high-protein diet

Animals fed a high-protein diet (50% casein) are hyperactive and more responsive to nociceptive stimuli than those fed either a normal- or low-protein diet. The mechanisms mediating dietary protein-induced behavior are unknown and may include both central and peripheral neural effects. Adult, Sprague-Dawley rats were fed 50% casein (treatment group) and 24% casein (control group) ad lib for 36-40 weeks. The animals were anesthetized with alpha-chloralose and urethane (50 mg/kg and 1.5 mg/kg, IP). EEG recordings were averaged while the anesthetized animal was conditioned using an alerting stimulus-imperative stimulus (AS-IS) paradigm. AS consisted of a 1.5 kHz, 90 dB tone cue. This was followed 2 seconds later by IS, an electrical tail stimulation (11 V, 1.4 s duration). Two negative deflections (N1 and N2) were generated by the frontal cortex during the AS-IS interstimulus interval. N1, an alerting response, was not different between the two groups. N2 amplitude and peak latency were significantly increased in the high-protein group (205% and 117% of control, respectively; p less than 0.05). N2 represents the activation of cells in the motor cortex. Brainstem auditory-evoked responses and somatosensory-evoked potentials also were recorded, but no differences were observed between the two diet groups. These data suggest that consumption of a high-protein diet results in an increase in central arousal mechanisms (measured by cortical negativity response), specifically involving increased excitability of the motor cortex, that is not associated with a disorder of information processing in the cerebral cortex (measured by brainstem auditory-evoked responses and somatosensory-evoked potentials).