Pharmacological evidence that GABA-induced relaxation of rat proximal duodenum longitudinal muscle depends on NKCC cotransporter activity and Ca2+ influx.

γ-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter in adult central nervous system (CNS) synapses, but it excites immature CNS neurons as well as neurons in the myenteric plexus. The present work aimed to determine whether GABA-induced nonadrenergic, noncholinergic (NANC) neuronal-mediated relaxation of the rat duodenum is dependent on the activity of Na+ K+ Cl- cotransporters (NKCC) and requires calcium influx. In the presence of guanethidine (3 µmol/L), atropine (3 µmol/L), and indomethacin (1 µmol/L), relaxations induced by GABA (100 µmol/L), KCl (5-10 mmol/L) and electrical field stimulation (1-8 Hz, 2 ms, 60 V), but not those induced by bradykinin (10-100 nmol/L) were abolished by lidocaine (300 µmol/L). However, only GABA-induced relaxations were reduced in a concentration-dependent manner by the NKCC1/2 inhibitors bumetanide (0.1-1 µmol/L) and furosemide (1-10 µmol/L). GABA-induced NANC neuronal relaxation was abolished by bicuculline (30 µmol/L) and inhibited by N-nitroarginine methyl ester (l-NAME, 300 µmol/L). The ω-conotoxin GVIA (1 µmol/L), which acts exclusively on neuronal CaV2 channels, but not on smooth muscle voltage-gated Ca2+ CaV1 channels, and nonselective blockers of these channels (verapamil 100 nmol/L and ruthenium red 10 µmol/L), reduced GABA-induced relaxations. These results showed that the activation of GABAA receptors induces NANC nitrergic neuronal relaxations in the rat duodenum, which depend on NKCC activity and CaV2 channel activation, suggesting that this phenomenon results from neuronal depolarization promoted by Cl- efflux through GABAA receptors, with subsequent Ca2+ influx and nitric oxide release.

Inhibitory effect of Pyr6 (an Orai channel blocker) on agonist-induced contractions in rat uterus.

AIM: Both human and rat myometrium express stromal interaction molecule (STIM) and Orai/transient receptor potential canonical (TRPC) proteins, which are components of plasma membrane Ca2+ store-operated channels. There are reports that these proteins mediate agonist-induced Ca2+ influx in cultured myometrial cells. In this study, we aimed to determine the effects of Pyr6, an Orai channel blocker, on different agonist-induced contractions in isolated segments of rat uterus. MAIN FINDINGS: In Ca2+ -free Tyrode's solution, Pyr6 (3 µM) promoted a reduction in both the magnitude and frequency of Ca2+ (1 mM)-induced uterine contractions after the addition of carbachol (CCh, 100 µM), but not after the addition of oxytocin (OT, 150 nM). In Ca2+ (0.18 mM)-Tyrode's solution, Pyr6 completely relaxed uterine contractions induced by both CCh and cloprostenol (300 nM), but not those induced by either KCI (40-80 mM) or OT. The addition of Pyr6 abolished the oscillatory uterine contractions induced by Ca2+ after the addition of cyclopiazonic acid (CPA, 10 µM). When pre-incubated (5 min), Pyr6 reduced the magnitude of both CCh-induced phasic and tonic contractions. The addition of Pyr2 (3 µM), an Orai and TRPC channel blocker, abolished uterine contractions induced by CCh or OT. CONCLUSION: Considering Pyr6 as an Orai channel blocker and its inhibitory effect on uterine contractions induced by CCh, CPA, and cloprostenol, we suggest that Orai channels are required for the maintenance of contractions induced by these agonists in rat uterus.

Neuropsychological aspects of reversible cerebral vasoconstriction syndrome.

Despite the increasing knowledge in the past years, only minimal attention has been directed to the neuropsychological aspects and the prevalence of cognitive impairment associated with reversible cerebral vasoconstriction syndrome (RCVS). Objective: To describe the frequency and expand the understanding of cognitive dysfunction in RCVS. Methods: The neuropsychological evaluation was performed using a battery consisting of specific neuropsychological instruments that were administered to patients diagnosed with RCVS. A triage was conducted to exclude other potential causes of cognitive impairment. Performance on the tests was treated as a categorical variable, and a cutoff of -1.5 Z-score was adopted to indicate impaired performance. Results: Seven patients diagnosed with RCVS were evaluated, all of whom had a bachelor's degree and normal score in the Mini-Mental State Examination. The average time between diagnosis and neuropsychological evaluation was 1.8 years. Among the patients, 85.6% (n=6) exhibited performance below that of the normal population in at least two of the administered tests. Specifically, 71.4% (n=5) showed alterations in tests from the Psychological Battery for Attention Assessment, with impairment observed in concentrated (n=1), divided (n=3), or alternating (n=4) attention. Furthermore, 28.6% (n=2) demonstrated impairments in the Phonological Verbal Fluency Task, another 28.6% (n=2) exhibited difficulties copying elements of the Rey Complex Figure, and 14.3% (n=1) displayed lower performance in the Five-Digit test, all indicating executive dysfunction. Conclusion: This study provides evidence that cognitive impairment associated with RCVS is more prevalent than previously believed and has not received sufficient attention. Specifically, attention and executive functions are the cognitive domains most significantly impacted by RCVS.

Apesar do crescente conhecimento nos últimos anos, pouca atenção tem sido direcionada aos aspectos neuropsicológicos e à prevalência de declínio cognitivo associado à Síndrome de Vasoconstrição Cerebral Reversível (SVCR). Objetivo: Descrever a frequência e expandir o entendimento da disfunção cognitiva associada à SVCR. Métodos: A avaliação neuropsicológica foi realizada por meio de uma bateria composta de instrumentos neuropsicológicos específicos, que foram aplicados aos pacientes com SVCR. Uma triagem foi realizada para excluir outras potenciais causas de declínio cognitivo. O desempenho nos testes foi considerado como variável categórica, e o corte de −1,5 escore z foi adotado para indicar desempenho comprometido. Resultados: Sete pacientes com diagnóstico de SVCR foram avaliados, os quais tinham todos nível de ensino superior e pontuação normal no Miniexame do Estado Mental. A média de tempo entre o diagnóstico e a avaliação neuropsicológica foi de 1,8 ano. Dentre os pacientes, 85,6%(n=6) apresentaram desempenho comprometido em pelo menos dois dos testes aplicados. Especificamente, 71,4% (n=5) apresentaram alterações nos testes da Bateria Psicológica para Avaliação da Atenção, com comprometimento observado nas atenções concentrada (n=1), dividida (n=3), ou alternada (n=4). Além disso, 28,6% (n=2) demonstraram comprometimento na Fluência Verbal Fonológica, 28,6% (n=2) exibiram dificuldades na cópia da Figura Complexa de Rey e um paciente obteve desempenho alterado no Teste dos Cinco Dígitos, todos indicando disfunção executiva. Conclusão: Este estudo fornece evidência de que o declínio cognitivo associado à SVCR é mais prevalente do que se acreditava anteriormente. Especialmente, os domínios mais significativamente comprometidos foram a atenção e as funções executivas.

Case report: Flow changes in routes of collateral circulation in patients with LVO and low NIHSS: a point favor to treat.

The effectiveness of endovascular thrombectomy in patients presenting low National Institutes of Health Stroke Scale (NIHSS) scores remains controversial, and the acquisition of additional evidence is required to refine the selection of candidates who may benefit the most from this therapeutic modality. In this study, we present the case of a 62-year-old individual, with left internal carotid occlusion stroke and low NIHSS, who had compensatory collateral flow from Willis polygon via the anterior communicating artery. The patient subsequently exhibited neurological deterioration and collateral flow failure from Willis polygon, indicating the need for urgent intervention. The study of collaterals in patients with large vessel occlusion stroke has garnered considerable attention, with research suggesting that individuals with low NIHSS scores and poor collateral profiles may be at a heightened risk of early neurological deterioration. We postulate that such patients may derive significant benefits from endovascular thrombectomy, and may posit that an intensive transcranial Doppler monitoring protocol could facilitate the identification of suitable candidates for such intervention.