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Introduction: Ciprofol is a new intravenous anesthetic with a similar chemical structure to propofol. We aimed to compare the incidence of adverse actions like injection pain and time indexes of ciprofol versus propofol on anesthesia in patients undergoing endoscopy. We also compared anesthetists' satisfaction during the procedure. Methods: Two independent researchers (Liu and Zeng) searched the Cochrane Library, Embase databases, and PubMed for controlled clinical trials. This meta-analysis of randomized controlled trials (RCTs) was performed with the Review Manager, Stata and the Cochrane Risk-of-Bias 2 tool to evaluate methodological quality. Relative risks with 95% confidence interval (CI) were calculated for outcomes. Results: Ten trials, including 1545 patients, were examined in the current meta-analysis. During anesthesia in patients undergoing endoscopy, the incidence of injection pain was significantly reduced in the research group. Compared with propofol, the pooled risk difference (RD) with the use of ciprofol for injection pain for all the procedures was − 0.34 (95% confidence interval [CI], -0.48 to 0.19), and RR for hypotension was 0.73(95% CI:0.58 to 0.92). GRADE showed this meta-analysis has moderate or low confidence. Trial sequential analysis for mortality indicated insufficient sample size for a definitive judgment for lower incidence of hypotension. Conclusion: In painless endoscopy, compared with propofol, ciprofol exhibited non-inferiority anesthesia/sedation in patients, and had a good safety profile with a lower incidence of pain on injection and may reduce the chance of hypotension. Trial sequential analysis suggested the need for more cases, and GRADE highlighted moderate certainty, emphasizing the necessity for further targeted RCTs. Systematic review registration: PROSPERO, CRD42023433627. [ABSTRACT FROM AUTHOR]

Agitated depression, also known as melancholia agitata, is a variant of depression characterized by severe symptoms of psychomotor agitation, inner unrest, anxiety, restlessness, prominent vegetative symptoms, and a high risk of suicide. This form of depression is reported to worsen with antidepressants and potentially improve with the use of ECT, lithium, antiepileptics, antipsychotics, and benzodiazepines. We describe a case of a 73‐year‐old female with a prior history of depression and generalized anxiety disorder who was maintained on flurazepam for 44 years and was admitted for severe depression with psychomotor agitation, prominent vegetative symptoms, thought perseveration, indecisiveness, and psychotic features that emerged following the discontinuation of flurazepam. Symptoms did not resolve with the use of alternative benzodiazepines such as nitrazepam and temazepam and further worsened with the use of several antidepressants. She finally had a complete resolution of these symptoms with a combination of alprazolam, zopiclone, and olanzapine. This case provides insight into this unique variant of depression and the role of GABA agonists in its pathology and management. [ABSTRACT FROM AUTHOR]

Etomidate, an agonist of the GABA A receptors, is available for clinical use either in combination with 35% propylene glycol or in a lipid emulsion. Its recognized ability to minimally impact the cardiovascular system made etomidate a suitable option for cardiac-compromised patients. Myoclonus and pain at the injection site are recognized side effects of etomidate in propylene glycol, affecting both human and veterinary species. There is no information available concerning potential side effect in minipigs. In the present case series, we report the side effects related to the use of etomidate in 35% propylene glycol in five Ellegaard Göttingen Minipigs that underwent general anesthesia for cardiac magnetic resonance imaging days or weeks after experimentally induced myocardial infarction. Following intravenous injection of etomidate, laryngeal edema and hyperemia were observed in one case. In another case, tachycardia, apnea, and decreased oxygen saturation, accompanied by laryngeal edema and hyperemia, were observed, which resolved spontaneously in a few minutes. In the arterial or venous samples collected shortly after the induction of general anesthesia, hemolysis was macroscopically visible and subsequently confirmed with a hematological exam in all five cases, as well as hemoglobinuria. Necropsies carried out immediately after euthanasia confirmed macroscopic laryngeal edema, marked diffuse lung alveolar and interstitial edema and hyperemia at histology in one animal, and marked acute lung congestion in another animal. These side effects were not observed when etomidate in a lipid emulsion was injected into another 24 animals. The role played by the different formulations (propylene glycol versus lipidic formulation) has not yet been fully elucidated. Based on our observations, we recommend caution in using the formulation of etomidate in 35% propylene glycol in Göttingen Minipigs. [ABSTRACT FROM AUTHOR]

Background: As a new type of intravenous anesthetic, ciprofol has the advantages of fast onset of action, fast recovery and high clearance rate. This study aimed to investigate the effectiveness and safety of ciprofol versus traditional propofol for anesthesia and sedation in and out of the operating room. Methods: We searched the literature in PubMed, Web of Science, Cochrane Library, and Embase databases from January 2021 to December 2023. All clinical studies comparing the sedative effects of propofol and ciprofol, both inside and outside the operating room, were included in our trial. The main outcome measures were induction time and incidence of injection-site pain. Data are merged using risk ratio and standardized mean difference with 95% confidence interval. Subgroup analysis, meta-regression, sensitivity analysis, and publication bias were performed. The study protocol was prospectively registered with PROSPERO (CRD42023447747). Results: A total of 15 randomized, controlled trials involving 2002 patients were included in this study. Compared with propofol, ciprofol has a longer induction time in the operating room but a shorter induction time in non-operating room settings. Ciprofol can effectively reduce the risk of injection-site pain and respiratory depression both inside and outside the operating room. In addition, the risk of drug-related hypotension induced with ciprofol in the operating room is lower, but the awakening time is also longer. Meta-regression analysis showed that neither age nor BMI were potential sources of heterogeneity. Funnel plot, egger and begg tests showed no significant publication bias. Sensitivity analyzes indicate that our results are robust and reliable. Conclusion: Ciprofol has absolute advantages in reducing the risk of injection-site pain and respiratory depression, both in and outside operating room. Intraoperative use of ciprofol reduces the risk of drug-related hypotension and may also reduce the risk of intraoperative physical movements. However, ciprofol may have longer induction and awakening time than propofol. [ABSTRACT FROM AUTHOR]

Background Positive allosteric modulators (PAMs) of the GABAB receptor constitute a new class of GABAB-receptor ligands. GABAB PAMs reproduce several pharmacological effects of the orthosteric GABAB receptor agonist, baclofen, although displaying a better safety profile. Aims This paper reviews the reducing or, frequently, even suppressing effects of all GABAB PAMs tested to date on multiple alcohol-related behaviours in laboratory rodents exposed to validated experimental models of human alcohol use disorder. Results Acute or repeated treatment with CGP7930, GS39783, BHF177, rac -BHFF, ADX71441, CMPPE, COR659, ASP8062, KK-92A, and ORM-27669 reduced excessive alcohol drinking, relapse- and binge-like drinking, operant alcohol self-administration, reinstatement of alcohol seeking, and alcohol-induced conditioned place preference in rats and mice. Conclusions These effects closely mirrored those of baclofen; notably, they were associated to remarkably lower levels of tolerance and toxicity. The recent transition of ASP8062 to clinical testing will soon prove whether these highly consistent preclinical data translate to AUD patients. [ABSTRACT FROM AUTHOR]

After unilateral peripheral vestibular lesions, the neural activity of neurons in the ipsi-lesional medial vestibular nucleus (ipsi-MVe) are markedly decreased, resulting in static and dynamic asymmetries of the vestibulo-ocular and vestibulo-spinal reflexes. Consequently, static vestibular symptoms such as spontaneous nystagmus and postural deviation and dynamic vestibular symptoms such as oscillopsia and swaying gait are induced. However, these behavioral asymmetries gradually recover after the lesion. Progressive balance restoration is termed vestibular compensation, which is divided into two phases: static and dynamic. Static vestibular compensation is further divided into initial and late processes. In the initial process of static vestibular compensation after unilateral labyrinthectomy (UL) in rats, plastic changes in the cerebello-vestibular and vestibular commissural inhibitory pathways suppress neurons in the contra-lesional MVe (contra-MVe), resulting in the restoration of symmetrical resting activity of MVe neurons on both sides at low levels. The declining frequency of spontaneous nystagmus after UL is an index of the initial process, and short-term administration of diazepam, a GABA A receptor agonist, has been shown to accelerate the initial process in rats. Accordingly, short-term administration of diazepam is recommended for the treatment of acute vertigo in patients with unilateral vestibular dysfunction. In the late process of static vestibular compensation after UL in rats, the resting activity of ipsi-MVe neurons gradually recovers due to changes in cell membrane properties, resulting in the reinforcement of balanced intervestibular nuclear activities to nearly normal levels without the suppression of contra-MVe neurons. The declining number of MK801-induced Fos-positive neurons in contra-MVe after UL is an index of the late process, and long-term administration of betahistine, a histamine H 3 receptor antagonist, has been shown to accelerate the late process in rats. Accordingly, long-term administration of betahistine is recommended for the treatment of subacute vertigo in patients who were not compensated for unilateral vestibular dysfunction. In the process of dynamic vestibular compensation after UL, the sensitivity of ipsi-MVe neurons to head velocity and acceleration is restored due to synaptic changes such as long-term potentiation and sprouting of commissures, resulting in the restoration of the dynamic vestibulo-ocular and vestibulo-spinal reflexes. To facilitate dynamic vestibular compensation, early ambulation and subsequent vestibular rehabilitation exercise are recommended for the treatment of chronic vertigo in patients with uncompensated unilateral vestibular dysfunction. Although vestibular compensation after bilateral vestibular loss is not expected, vestibular rehabilitation with a sensory-substitution strategy can improve imbalance in patients with bilateral vestibular lesions. [ABSTRACT FROM AUTHOR]

Background: Phenibut (β-phenyl-γ-aminobutyric acid) is an analog of the neurotransmitter gamma-aminobutyric acid (GABA). Like abapentin and pregabalin, it inhibits α2-δsubunits of voltage-dependent presynaptic calcium channels. The potential harm resulting from the use of these gabapentinoids is currently a matter of debate. Methods: This review is based on pertinent publications retrieved by a selective literature search and on cases reported to the Giftinformationszentrum-Nord (GIZ-Nord), a poison information center at the University of Gttingen, Germany. Results: Phenibut is a prescription drug in Russia but its production, possession, use, trafficking, or administration is illegal in Germany. The phenibut toxicity syndrome resembles that of gabapentinoids and GABA mimetics: benzodiazepine-like withdrawal symptoms including epileptic seizures, delirium and paradoxical activation have been described, as have cases of abuse and dependence. A few cases of use in the setting of multidrug abuse, and of phenibut-related death, have been described to date in the USA. The GIZ-Nord received 17 inquiries about phenibut, 55 about gabapentin, and 126 about pregabalin over the period 20082022. Over the same period, the GIZ-Nord was informed of 1207 cases involving Z substances and 4324 involving benzodiazepines. In the majority of the registered intoxications, including those with phenibut, the symptoms were mild. Overdoses of phenibut (2100 g) were reported in 15 of the 17 cases; 8 of the persons who had taken an overdose were somnolent. In such cases, observation in intensive care was recommended. Respiratory depression or coma was not encountered in any case, not even in the patient who had taken 100 g of phenibut. Conclusion: Phenibut causes symptoms resembling those of gabapentinoid and benzodiazepine use. There have been reports of phenibut use in combination with other psychotropic drugs; in particular, its use together with opiates could increase the risk of coma and respiratory depression. No deaths due to phenibut intoxication have been published in Germany or elsewhere in Western Europe, although such cases may have been overlooked, as this drug is still largely unknown to Western medicine. [ABSTRACT FROM AUTHOR]

Background: Catatonia has been increasingly associated with mood disorders and is recognized as a specifier in the DSM-5 and DSM-5-TR. The DSM-5-TR recognizes melancholia as a specifier for depressive episodes in major depressive disorder and bipolar disorder. It is characterized by severe anhedonia, lack of reactivity, excessive or delusional guilt, and significant vegetative symptoms. As the conceptualization of melancholia expanded beyond its mood components to include psychomotor disturbances, its overlap with psychomotor symptoms or catatonia becomes evident. This overlap was also described in Kahlbaum's original literature, where he describes the transition between states of melancholia, mania, and catatonia. Method: Case summary of six patients with major depressive disorder or depressed phase of bipolar disorder who were admitted for severe depression, anhedonia, intense anxiety, psychomotor agitation or retardation, indecisiveness, perseveration, and vegetative symptoms such as poor sleep, appetite, and significant weight loss. Results: All patients demonstrated rapid and complete resolution of their mood and psychomotor symptoms, indecisiveness, perseveration, as well as psychosis shortly after administration of lorazepam, with recurrence of the above symptoms upon lorazepam discontinuation and resolution upon resumption, in an on-and-off manner. Conclusion: The present study argues for a closer relationship between melancholia and catatonia based on our case series, historical review, overlap in phenomenology, and response to treatment. We propose provisional [Mahgoub] criteria for patients with severe depression and melancholia. The role of GABA agonists, such as lorazepam, can be explored as an option for patients with treatment-resistant depression who meet these criteria for melancholia. Limitations: Absence of a standardized, systematic assessment tool and a small sample size. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is a progressive neurodegenerative disease as a result of the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc). The fundamental features of PD are motor and non-motor symptoms. PD symptoms develop due to the disruption of dopaminergic neurotransmitters and other neurotransmitters such as γ-aminobutyric acid (GABA). The potential role of GABA in PD neuropathology concerning the motor and non-motor symptoms of PD was not precisely discussed. Therefore, this review intended to illustrate the possible role of GABA in PD neuropathology regarding motor and non-motor symptoms. The GABA pathway is essential in regulating the inhibitory tone to prevent excessive stimulation of the cerebral cortex. Degeneration of dopaminergic neurons in PD is linked with reducing GABAergic neurotransmission. Decreasing GABA activity promotes mitochondrial dysfunction and oxidative stress, which are highly related to PD neuropathology. Hence, restoring GABA activity by GABA agonists may attenuate the progression of PD motor symptoms. Therefore, dysregulation of GABAergic neurons in the SNpc contributes to developing PD motor symptoms. Besides, PD non-motor symptoms are also related to the dysfunction of the GABAergic pathway, and amelioration of this pathway may reduce PD non-motor symptoms. In conclusion, the deregulation of the GABAergic pathway in PD might be intricate in developing motor and non-motor symptoms. Improving this pathway might be a novel, beneficial approach to control PD symptoms. [ABSTRACT FROM AUTHOR]

Schizophrenia is a disease with a complex pathological mechanism that is influenced by multiple genes. The study of its pathogenesis is dominated by the dopamine hypothesis, as well as other hypotheses such as the 5-hydroxytryptamine hypothesis, glutamate hypothesis, immune-inflammatory hypothesis, gene expression abnormality hypothesis, and neurodevelopmental abnormality hypothesis. The first generation of antipsychotics was developed based on dopaminergic receptor antagonism, which blocks dopamine D2 receptors in the brain to exert antipsychotic effects. The second generation of antipsychotics acts by dual blockade of 5-hydroxytryptamine and dopamine receptors. From the third generation of antipsychotics onwards, the therapeutic targets for antipsychotic schizophrenia expanded beyond D2 receptor blockade to explore D2 receptor partial agonism and the antipsychotic effects of new targets such as D3, 5-HT1A, 5-HT7, and mGlu2/3 receptors. The main advantages of the second and third generation antipsychotics over first-generation antipsychotics are the reduction of side effects and the improvement of negative symptoms, and even though third-generation antipsychotics do not directly block D2 receptors, the modulation of the dopamine transmitter system is still an important part of their antipsychotic process. According to recent research, several receptors, including 5-hydroxytryptamine, glutamate, γ-aminobutyric acid, acetylcholine receptors and norepinephrine, play a role in the development of schizophrenia. Therefore, the focus of developing new antipsychotic drugs has shifted towards agonism or inhibition of these receptors. Specifically, the development of NMDARs stimulants, GABA receptor agonists, mGlu receptor modulators, cholinergic receptor modulators, 5-HT2C receptor agonists and alpha-2 receptor modulators has become the main direction. Animal experiments have confirmed the antipsychotic effects of these drugs, but their pharmacokinetics and clinical applicability still require further exploration. Research on alternative targets for antipsychotic drugs, beyond the dopamine D2 receptor, has expanded the potential treatment options for schizophrenia and gives an important way to address the challenge of refractory schizophrenia. This article aims to provide a comprehensive overview of the research on therapeutic targets and medications for schizophrenia, offering valuable insights for both treatment and further research in this field. [ABSTRACT FROM AUTHOR]

Electroencephalograms (EEGs) display a mixture of rhythmic and broadband fluctuations, the latter manifesting as an apparent 1/f spectral trend. While network oscillations are known to generate rhythmic EEG, the neural basis of broadband EEG remains unexplained. Here, we use biophysical modelling to show that aperiodic neural activity can generate detectable scalp potentials and shape broadband EEG features, but that these aperiodic signals do not significantly perturb brain rhythm quantification. Further model analysis demonstrated that rhythmic EEG signals are profoundly corrupted by shifts in synapse properties. To examine this scenario, we recorded EEGs of human subjects being administered propofol, a general anesthetic and GABA receptor agonist. Drug administration caused broadband EEG changes that quantitatively matched propofol's known effects on GABA receptors. We used our model to correct for these confounding broadband changes, which revealed that delta power, uniquely, increased within seconds of individuals losing consciousness. Altogether, this work details how EEG signals are shaped by neurophysiological factors other than brain rhythms and elucidates how these signals can undermine traditional EEG interpretation. The neural mechanisms that give rise to aperiodic EEG signals remains unclear. Here the authors characterize EEG signals generated by neural processes other than brain rhythms, demonstrating that certain drugs alter EEG signals in ways that confound traditional interpretation. [ABSTRACT FROM AUTHOR]

Aims: To increase our understanding of which factors contribute to long‐term benzodiazepine receptor agonist (BZRA) use for insomnia in primary care, from a patients', general practitioners' (GP) and pharmacists' perspective. Design: Qualitative research following a grounded theory approach. Setting: Primary care in Belgium. Participants: Twenty‐four participants were interviewed, including nine patients, six GPs and nine pharmacists. Measurements: In‐depth, semistructured interviews with iterative cycles of data collection and analysis. Transcripts were analysed using the framework method. Thematic findings were interpreted in the context of the Theoretical Domains Framework. Findings: A reflexive relation was identified between views about hypnotic use at the level of society, healthcare and patients. Behaviour change appeared to depend strongly on context and social influence, including a need for supporting relationships by all stakeholders. Six key messages captured factors that contribute to long‐term BZRA use for insomnia in primary care: societal beliefs as a game changer, the opportunity of nonpharmacological treatment, collaborative primary care, patient‐centred goals, informed consent and self‐management. Conclusions: Long‐term BZRA use for insomnia is a complex and multifaceted public health problem that is not adequately addressed in primary care at this time. Although primary care professionals in this study found discontinuation of long‐term BZRA use relevant to the patient's health, many organisational and personal barriers were reported. Moreover, the current social and healthcare context is not empowering patients and professionals to reduce long‐term BZRA use for insomnia. Specifically, for primary care, all stakeholders reported the need for a nonmedicalised relationship between the patient and GP to lower prescribing rates. Patient or Public Contribution: The Flemish Patient Platform, a patient representative organisation, assisted with recruitment by launching a call for participants in their newsletter and volunteered to disseminate the results. The call for recruitment was also published online in social media groups regarding insomnia and via posters in public pharmacies. Patients or public were not involved in designing or conducting the interview study. [ABSTRACT FROM AUTHOR]

Previous neuroscientific research has expounded on the fundamental role played by emotion during moral decision-making. Negative emotionality has been observed to exert a general inhibitory effect towards harmful behaviors against others. Nevertheless, the downregulation of negative affects at different levels of moral processing (e.g. impersonal versus personal moral dilemmas) alongside its possible interactions with other factors (e.g. perspective taking) hasn't been directly assessed; both of which can assist in predicting future moral decision-making. In the present research, we empirically test (Study 1, N = 41) whether downregulating negative emotionality through pharmacological interventions using lorazepam (a GABA receptor agonist), modulate the permissibility of harm to others –i.e. if participants find it more morally permissible to harm others when harm is unavoidable (inevitable harm moral dilemmas), than when it may be avoided (evitable harm moral dilemmas). Furthermore, using another sample (Study 2, N = 31), we assess whether lorazepam's effect is modulated by different perspective-taking conditions during a moral dilemma task –e.g. "is it morally permissible for you to [...]?" (1st person perspective), relative to "is it morally permissible for [x individual] to [...]?" (3rd person perspective)–, where the outcome of the different scenarios is controlled. The results of both studies converge, revealing an emotion-dependent, rather than an outcome-dependent, pharmacological modulation. Lorazepam only influenced interpersonal moral judgments when not modulated by the evitable/inevitable condition. Furthermore, there was a significant interaction between perspective-taking and drug administration, as lorazepam exerted a larger effect in modulating moral choices rather than moral judgements. [ABSTRACT FROM AUTHOR]

Background: Ciprofol is a novel intravenous sedative and anesthetic. Studies have shown that it features a rapid onset of action, a fast recovery time, slight inhibition of respiratory and cardiovascular functions, and a low incidence of adverse reactions. This study aims to explore the median effective dose (ED50) and the 95% effective dose (ED95) of ciprofol in inhibiting responses to gastroscope insertion when combined with a low dose of alfentanil, and to evaluate its safety, to provide a reference for the rational use of ciprofol in clinical practices. Methods: We included 25 patients aged 18–64 years of either sex who underwent gastroscopy under intravenous general anesthesia, with a Body Mass Index (BMI) 18–28 kg/m2, and an American Society of Anesthesiologists (ASA) grade I or II. In this study, the dose-finding strategy of ciprofol followed a modified Dixon's up-and-down method with an initial dose of 0.30 mg/kg and an increment of 0.02 mg/kg. Ciprofol was administered after intravenous injection of 7 µg/kg of alfentanil, and 2 min later a gastroscope was inserted. When the insertion response of one participant was positive (including body movement, coughing, and eye opening), an escalation of 0.02 mg/kg would be given to the next participant; otherwise, a de-escalation of 0.02 mg/kg would be administered. The study was terminated when negative response and positive response alternated 8 times. A Probit model was used to calculate the ED50 and ED95 of ciprofol in inhibiting responses to gastroscope insertion when combined with alfentanil. Patients' recovery time, discharge time, vital signs and occurrence of adverse reactions were recorded. Results: The ED50 of single-dose intravenous ciprofol injection with 7 µg/kg of alfentanil in inhibiting gastroscope insertion responses was 0.217 mg/kg, and the ED95 was 0.247 mg/kg. Patients' recovery time and discharge time were 11.04 ± 1.49 min and 9.64 ± 2.38 min, respectively. The overall incidence of adverse reactions was 12%. Conclusion: The ED50 of ciprofol combined with 7 µg/kg of alfentanil in inhibiting gastroscope insertion responses was 0.217 mg/kg, and the ED95 was 0.247 mg/kg. Ciprofol showed a low incidence of anesthesia-related adverse events. Trial registration: http://www.chictr.org.cn (ChiCTR2200061727). [ABSTRACT FROM AUTHOR]

BACKGROUND: Anti-glutamate decarboxylase 65 antibody-associated cerebellar ataxia (anti-GAD65Ab-associated CA) is the most widely studied immune-mediated CA. There are few case series evaluating the clinical, radiological, treatment profile, and outcome of anti-GAD65Ab-associated CA. OBJECTIVE: To study the clinical, radiological profile, associated neoplasm, treatment outcome, and prognosis in patients diagnosed with anti-GAD65Ab-associated CA. METHODS: A retrospective descriptive analysis of a cohort of patients diagnosed with anti-GAD65Abassociated CA was performed and analyzed. RESULTS: Thirteen patients were selected for the analysis with female predominance (70%). The mean age at presentation was 47.5 ± 11.1 years (range, 29-65 years), and the median duration of the symptoms was 4 months. All 13 patients (100%) had gait ataxia. Ten patients had limb ataxia along with gait ataxia (75%). Seven patients had cerebellar dysarthria (54%). Four patients (31%) had gazeevoked jerky nystagmus. Five patients (39%) were diagnosed with type 2 diabetes mellitus, and one patient had hypothyroidism in addition to type 2 diabetes mellitus. Brain magnetic resonance imaging was normal in seven (54%) patients, and pure cerebellar atrophy was observed in six patients. One patient was detected with a colon neoplasm. All 13 patients received intravenous methylprednisolone, followed by oral steroids over 3 months. Six patients (50%) received plasma exchange along with intravenous methylprednisolone. Favorable outcomes (modified Rankin scale score =2) were observed in five patients and poor outcomes in two; six patients were lost to follow-up after the first admission. CONCLUSION: Anti-GAD65Ab-associated CA presents as subacute to chronic progressive CA with a favorable outcome with immunotherapy. Anti-GAD antibodies should be assessed in serum or cerebrospinal fluid in patients presenting subacute to chronic sporadic CA. The occurrence of a systemic neoplasm is rare in anti-GAD65Ab-associated CA. [ABSTRACT FROM AUTHOR]

In this column, Sharon Rees aims to refresh knowledge and interest in some of the commonly used drugs in a series of posts on X. This month she is talking about #baclofen [ABSTRACT FROM AUTHOR]

GABA (γ-aminobutyric acid) receptors are constituents of many inhibitory synapses within the central nervous system. They are formed by 5 subunits out of 19 various subunits: α1–6, β1–3, γ1–3, δ, ε, θ, π, and ρ1–3. Two main subtypes of GABA receptors have been identified, namely GABAA and GABAB. The GABAA receptor (GABAAR) is formed by a variety of combinations of five subunits, although both α and β subunits must be included to produce a GABA-gated ion channel. Other subunits are γ, δ, ε, π, and ϴ. GABAAR has many isoforms, that dictate, among other properties, their differing affinities and conductance. Drugs acting on GABAAR form the cornerstone of anesthesia and sedation practice. Some such GABAAR agonists used in anesthesia practice are propofol, etomidate, methohexital, thiopental, isoflurane, sevoflurane, and desflurane. Ketamine, nitrous oxide, and xenon are not GABAR agonists and instead inhibit glutamate receptors—mainly NMDA receptors. Inspite of its many drawbacks such as pain in injection, quick and uncontrolled conversion from sedation to general anesthesia and dose-related cardiovascular depression, propofol remains the most popular GABAR agonist employed by anesthesia providers. In addition, being formulated in a lipid emulsion, contamination and bacterial growth is possible. Literature is rife with newer propofol formulations, aiming to address many of these drawbacks, and with some degree of success. A nonemulsion propofol formulation has been developed with cyclodextrins, which form inclusion complexes with drugs having lipophilic properties while maintaining aqueous solubility. Inhalational anesthetics are also GABA agonists. The binding sites are primarily located within α+/β− and β+/α− subunit interfaces, with residues in the α+/γ− interface. Isoflurane and sevoflurane might have slightly different binding sites providing unexpected degree of selectivity. Methoxyflurane has made a comeback in Europe for rapid provision of analgesia in the emergency departments. Penthrox (Galen, UK) is the special device designed for its administration. With better understanding of pharmacology of GABAAR agonists, newer sedative agents have been developed, which utilize “soft pharmacology,” a term pertaining to agents that are rapidly metabolized into inactive metabolites after producing desired therapeutic effect(s). These newer “soft” GABAAR agonists have many properties of ideal sedative agents, as they can offer well-controlled, titratable activity and ultrashort action. Remimazolam, a modified midazolam and methoxycarbonyl-etomidate (MOC-etomidate), an ultrashort-acting etomidate analog are two such examples. Cyclopropyl methoxycarbonyl metomidate is another second-generation soft etomidate analog that has a greater potency and longer half-life than MOC-etomidate. Additionally, it might not cause adrenal axis suppression. Carboetomidate is another soft analog of etomidate with low affinity for 11β-hydroxylase and is, therefore, unlikely to have clinically significant adrenocortical suppressant effects. Alphaxalone, a GABAAR agonist, is recently formulated in combination with 7-sulfobutylether-β-cyclodextrin (SBECD), which has a low hypersensitivity profile. [ABSTRACT FROM AUTHOR]

• α4βδ GABA A receptors increase at puberty in layer 3 male prelimbic cortex. • Targeting these receptors with drugs or by knock-out alters spine pruning. • α4 knock-out increases spines and impairs temporal order memory. • An α4βδ agonist decreases spines and impairs temporal order memory. • These findings may be relevant for ASD and SCZ where spine density/recency memory are abnormal. Temporal order memory is impaired in autism spectrum disorder (ASD) and schizophrenia (SCZ). These disorders, more prevalent in males, result in abnormal dendritic spine pruning during adolescence in layer 3 (L3) medial prefrontal cortex (mPFC), yielding either too many (ASD) or too few (SCZ) spines. Here we tested whether altering spine density in neural circuits including the mPFC could be associated with impaired temporal order memory in male mice. We have shown that α4βδ GABA A receptors (GABARs) emerge at puberty on spines of L5 prelimbic mPFC (PL) where they trigger pruning. We show here that α4βδ receptors also increase at puberty in L3 PL (P < 0.0001) and used these receptors as a target to manipulate spine density here. Pubertal injection (14 d) of the GABA agonist gaboxadol, at a dose (3 mg/kg) selective for α4βδ, reduced L3 spine density by half (P < 0.0001), while α4 knock-out increased spine density ∼ 40 % (P < 0.0001), mimicking spine densities in SCZ and ASD, respectively. In both cases, performance on the mPFC-dependent temporal order recognition task was impaired, resulting in decreases in the discrimination ratio which assesses preference for the novel object: −0.39 ± 0.15, gaboxadol versus 0.52 ± 0.09, vehicle; P = 0.0002; −0.048 ± 0.10, α4 KO versus 0.49 ± 0.04, wild-type; P < 0.0001. In contrast, the number of approaches was unaltered, reflecting unchanged locomotion. These data suggest that altering α4βδ GABAR expression/activity alters spine density in L3 mPFC and impairs temporal order memory to mimic changes in ASD and SCZ. These findings may provide insight into these disorders. [ABSTRACT FROM AUTHOR]

North Sea Progressive Myoclonus Epilepsy (NS-PME) is a rare genetic disorder characterized by ataxia, myoclonus and seizures with a progressive course. Although the cause of NS-PME is known, namely a homozygous mutation in the GOSR2 gene (c.430 G>T; p. Gly144Trp), sufficient treatment is lacking. Despite combinations of on average 3–5 anti-seizure medications (ASMs), debilitating myoclonus and seizures persist. Here we aimed to gain insight into the most effective anti-convulsive target in NS-PME by evaluating the individual effects of ASMs in a NS-PME Drosophila model. A previously generated Drosophila model for NS-PME was used displaying progressive heat-sensitive seizures. We used this model to test 1. a first-generation ASM (sodium barbital), 2. common ASMs used in NS-PME (clonazepam, valproic acid, levetiracetam, ethosuximide) and 3. a novel third-generation ASM (ganaxolone) with similar mode of action to sodium barbital. Compounds were administered by adding them to the food in a range of concentrations. After 7 days of treatment, the percentage of heat-induced seizures was determined and compared to non-treated but affected controls. As previously reported in the NS-PME Drosophila model, sodium barbital resulted in significant seizure suppression, with increasing effect at higher dosages. Of the commonly prescribed ASMs, clonazepam and ethosuximide resulted in significant seizure suppression, whereas both valproic acid and levetiracetam did not show any changes in seizures. Interestingly, ganaxolone did result in seizure suppression as well. Of the six drugs tested, three of the four that resulted in seizure suppression (sodium barbital, clonazepam, ganaxolone) are primary known for their direct effect on GABA A receptors. This suggests that GABA A could be a potentially important target in the treatment of NS-PME. Consequently, these findings add rationale to the exploration of the clinical effect of ganaxolone in NS-PME and other progressive myoclonus epilepsies. • Progressive Myoclonus Epilepsies (PME) are notoriously difficult to treat. • This study evaluates ASMs in a validated North Sea-PME (NS-PME) Drosophila model. • GABA A agonists significantly suppress seizures in a NS-PME Drosophila model. • A new GABA A agonist ganaxolone effectively suppresses seizures in NS-PME Drosophila. • Ganaxolone could be a potential new treatment for NS-PME and other PMEs. [ABSTRACT FROM AUTHOR]

Abl2/Arg (ABL-related gene) is a member of the Abelson family of nonreceptor tyrosine kinases, known for its role in tumor progression, metastasis, tissue injury responses, inflammation, neural degeneration, and other diseases. In this study, we developed Abl2/Arg knockout (abl2 -/- ) mice to explore its impact on sensory/motor functions and emotion-related behaviors. Our findings show that abl2 -/- mice exhibit normal growth and phenotypic characteristics, closely resembling their wild-type (WT) counterparts. Behavioral tests, including the elevated plus maze, marble-burying behavior test, and open field test, indicated pronounced anxiety-like behaviors in abl2 -/- mice compared to WT mice. Furthermore, in the tail suspension test, abl2 -/- mice showed a significant decrease in mobility time, suggesting depressive-like behavior. Conversely, in the Y-maze and cliff avoidance reaction tests, no notable differences were observed between abl2 -/- and WT mice, suggesting the absence of working memory deficits and impulsivity in abl2 -/- mice. Proteomic analysis of the hippocampus in abl2 -/- mice highlighted significant alterations in proteins related to anxiety and depression, especially those associated with the GABAergic synapse in inhibitory neurotransmission. The expression of Gabbr2 was significantly reduced in the hippocampus of abl2 -/- compared to WT mice, and intraperitoneal treatment of GABA receptor agonist Gaboxadol normalized anxiety/depression-related behaviors of abl2 -/- mice. These findings underscore the potential role of Abl2/Arg in influencing anxiety and depressive-like behaviors, thereby contributing valuable insights into its broader physiological and pathological functions. [ABSTRACT FROM AUTHOR]

Background: Tuberous Sclerosis Complex (TSC) manifests behaviorally with features of autism, epilepsy, and intellectual disability. Resting state electroencephalography (EEG) offers a window into neural oscillatory activity and may serve as an intermediate biomarker between gene expression and behavioral manifestations. Such a biomarker could be useful in clinical trials as an endpoint or predictor of treatment response. However, seizures and antiepileptic medications also affect resting neural oscillatory activity and could undermine the utility of resting state EEG features as biomarkers in neurodevelopmental disorders such as TSC., Methods: This paper compares resting state EEG features in a cross-sectional cohort of young children with TSC (n=49, ages 12-37 months) to 49 age- and sex-matched typically developing controls. Within children with TSC, associations were examined between resting state EEG features, seizure severity composite score, and use of GABA agonists., Results: Compared to matched typically developing controls, children with TSC showed significantly greater alpha and beta power in permutation cluster analyses iterated across a broad frequency range (2-50Hz). Children with TSC also showed significantly greater aperiodic offset after power spectra were parameterized using SpecParam into aperiodic and periodic components. Within children with TSC, greater seizure severity was significantly related to increased periodic peak beta power. Use of GABA agonists was also independently and significantly associated with increased periodic peak beta power; the interaction between seizure severity and GABA agonist use had no significant effect on peak beta power., Conclusions: The elevated peak beta power observed in children with TSC compared to matched typically developing controls may be driven by both seizures and GABA agonist use. It is recommended to collect seizure and mediation data alongside EEG data for clinical trials. These results highlight the challenge of using resting state EEG features as biomarkers in trials with neurodevelopmental disabilities when epilepsy and anti-epileptic medication are common., Competing Interests: Declarations of interest: CCC, AME, CLW, CH, MH, AS, HTF, and CAN declare no conflict of interest. SJ reports a relationship with TSC Alliance that includes board membership and travel reimbursement

Alzheimer's disease (AD) is the most common cause of dementia in the elderly. Recent evidence suggests that gamma-aminobutyric acid B (GABA B) receptor-mediated inhibition is a major contributor to AD pathobiology, and GABA B receptors have been hypothesized to be a potential target for AD treatment. The aim of this study is to determine how GABA B regulation alters cognitive function and brain activity in an AD mouse model. Early, middle and late stage (8–23 months) amyloid precursor protein (APP) and presenilin 1 (PS1) transgenic mice were used for the study. The GABA B agonist baclofen (1 and 2.5 mg/kg, i. p.) and the antagonist phaclofen (0.5 mg/kg, i. p.) were used. Primarily, we found that GABA B activation was able to improve spatial and/or working memory performance in early and late stage AD animals. In addition, GABA B activation and inhibition could regulate global and local EEG oscillations in AD animals, with activation mainly regulating low-frequency activity (delta-theta bands) and inhibition mainly regulating mid- and high-frequency activity (alpha-gamma bands), although the regulated magnitude at some frequencies was reduced in AD. The cognitive improvements in AD animals may be explained by the reduced EEG activity in the theta frequency band (2–4 Hz). This study provides evidence for a potential therapeutic effect of baclofen in the elderly AD brain and for GABA B receptor-mediated inhibition as a potential therapeutic target for AD. • GABA B agonist baclofen improved spatial and working memory in AD mice. • Baclofen also increased their anxiety. • Baclofen regulated mainly low-frequency EEG activity. • GABA B antagonist phaclofen regulated mid- and high-frequency EEG activity. [ABSTRACT FROM AUTHOR]

• Inhibition of S1 significantly reduces motor performance during training session and performance improvement during post-test session. • The inhibition of S1 causes less formation and more elimination of dendritic spines of layer V pyramidal neurons in M1 after motor training. • S1 inhibition leads to decreased calcium activities of M1 neurons during both resting and running states. • S1, but not M1, is required for executing the acquired motor task in well-trained mice. The primary somatosensory cortex (S1) is responsible for processing information related to tactile stimulation, motor learning and control. Despite its significance, the connection between S1 and the primary motor cortex (M1), as well as its role in motor learning, remains a topic of ongoing exploration. In the present study, we silenced S1 by the GABA receptor agonist muscimol to study the potential roles of S1 in motor learning and task execution. Our results show that the inhibition of S1 leads to an immediate impairment in performance during the training session and also a substantial reduction in performance improvement during post-test session on the subsequent day. To understand the underlying mechanism, we used intravital two-photon imaging to investigate the dynamics of dendritic spines of layer V pyramidal neurons and the calcium activities of pyramidal neurons in M1 after inhibition of S1. Notably, S1 inhibition reduces motor training-induced spine formation and facilitates the elimination of existing spines of layer V pyramidal neurons in M1. The calcium activities in M1 exhibit a significant decrease during both resting and running periods following S1 inhibition. Furthermore, inhibition of S1, but not M1, significantly impairs the execution of the acquired motor task in the well-trained animals. Together, these findings reveal that S1 plays important roles in motor learning and task execution. [ABSTRACT FROM AUTHOR]

The ventrolateral orbital cortex (VLO) is identified as an integral component of the endogenous analgesic system comprising a spinal cord - thalamic nucleus submedius - VLO - periaqueductal gray (PAG) - spinal cord loop. The present study investigates the effects of 5-HT 5A receptor activation in the VLO on allodynia induced by spared nerve injury and formalin-evoked flinching behavior and spinal c-Fos expression in male SD rats, and further examines whether GABAergic modulation is involved in the effects evoked by VLO 5-HT 5A receptor activation. We found an upregulation of 5-HT 5A receptor expression in the VLO during neuropathic and inflammatory pain states. Microinjection of the non-selective 5-HT 5A receptor agonist 5-CT into the VLO dose dependently alleviated allodynia, and flinching behavior and spinal c-Fos expression, which were blocked by the selective 5-HT 5A receptor antagonist SB-699551. Moreover, application of the GABA A receptor antagonist bicuculline in the VLO augmented the analgesic effects induced by 5-CT in neuropathic and inflammatory pain states, whereas the GABA A receptor agonist muscimol attenuated these analgesic effects. Additionally, the 5-HT 5A receptors were found to be colocalized with GABAergic neurons in the VLO. These results provide new evidence for the involvement of central 5-HT 5A receptors in the VLO in modulation of neuropathic and inflammatory pain and support the hypothesis that activation of 5-HT 5A receptors may inhibit the inhibitory effect of GABAergic interneurons on output neurons projecting to the PAG (GABAergic disinhibitory mechanisms), consequently activating the brainstem descending inhibitory system that depresses nociceptive transmission at the spinal cord level. • Activation of 5-HT 5A receptor in the VLO attenuates allodynia of neuropathic pain. • Activation of VLO 5-HT 5A receptor alleviates flinching behavior in inflammatory pain. • Activation of VLO 5-HT 5A receptor reduces spinal Fos expression in inflammatory pain. • The analgesia of VLO 5-HT 5A receptor is mediated by GABAergic disinhibition. • The expression of 5-HT 5A receptor upregulates in neuropathic and inflammatory pain. [ABSTRACT FROM AUTHOR]

The mammalian three-phase respiratory motor pattern of inspiration, post-inspiration and expiration is expressed in spinal and cranial motor nerve discharge and is generated by a distributed ponto-medullary respiratory pattern generating network. Respiratory motor pattern generation depends on a rhythmogenic kernel located within the pre-Bötzinger complex (pre-BötC). In the present study, we tested the effect of unilateral and bilateral inactivation of the pre-BötC after local microinjection of the GABA A receptor agonist isoguvacine (10 mM, 50 nl) on phrenic (PNA), hypoglossal (HNA) and vagal nerve (VNA) respiratory motor activities in an in situ perfused brainstem preparation of rats. Bilateral inactivation of the pre-BötC triggered cessation of phrenic (PNA), hypoglossal (HNA) and vagal (VNA) nerve activities for 15–20 min. Ipsilateral isoguvacine injections into the pre-BötC triggered transient (6–8 min) cessation of inspiratory and post-inspiratory VNA (p < 0.001) and suppressed inspiratory HNA by − 70 ± 15% (p < 0.01), while inspiratory PNA burst frequency increased by 46 ± 30% (p < 0.01). Taken together, these observations confirm the role of the pre-BötC as the rhythmogenic kernel of the mammalian respiratory network in situ and highlight a significant role for the pre-BötC in the transmission of vagal inspiratory and post-inspiratory pre-motor drive to the nucleus ambiguus. • Unilateral inactivation of pre-Bötzinger complex selectively abolishes vagal inspiratory/postinspiratory motor discharge. • Bilateral inhibition of pre-Bötzinger complex abolishes all rhythmic respiratory motor discharge. • The pre-Bötzinger complex is part of a distributed respiratory network that controls postinspiratory activity. • The pre-Bötzinger complex serves as the respiratory rhythm generator in the perfused brainstem preparation. [ABSTRACT FROM AUTHOR]