Voltage-gated sodium channels (VGSCs) in primary sensory neurons play a key role in transmitting pain signals to the central nervous system. BmK I, a site-3 sodium channel-specific toxin from scorpion Buthus martensi Karsch, induces pain behaviors in rats. However, the subtypes of VGSCs targeted by BmK I were not entirely clear. We therefore investigated the effects of BmK I on the current amplitude, gating and kinetic properties of Nav1.8, which is associated with neuronal hyperexcitability in DRG neurons. It was found that BmK I dose-dependently increased Nav1.8 current in small-sized (<25 μm) acutely dissociated DRG neurons, which correlated with its inhibition on both fast and slow inactivation. Moreover, voltage-dependent activation and steady-state inactivation curves of Nav1.8 were shifted in a hyperpolarized direction. Thus, BmK I reduced the threshold of neuronal excitability and increased action potential firing in DRG neurons. In conclusion, our data clearly demonstrated that BmK I modulated Nav1.8 remarkably, suggesting BmK I as a valuable probe for studying Nav1.8. And Nav1.8 is an important target related to BmK I-evoked pain.
Aniline Compounds ; pharmacology ; Animals ; Cell Size ; Cells, Cultured ; Electrophysiological Phenomena ; drug effects ; Furans ; pharmacology ; Ganglia, Spinal ; cytology ; Kinetics ; Male ; NAV1.8 Voltage-Gated Sodium Channel ; metabolism ; Rats ; Rats, Sprague-Dawley ; Scorpion Venoms ; antagonists & inhibitors ; pharmacology ; Scorpions ; Sensory Receptor Cells ; drug effects ; metabolism ; physiology ; Sodium Channel Blockers ; pharmacology ; Voltage-Gated Sodium Channel Agonists ; pharmacology

Objective:To summarize and analyze the clinical, laboratory and imaging characteristics of patients with Caroli syndrome (CS), so as to deepen the understanding of the disease and explore the possible methods for improving early diagnosis.Methods:From January 2008 to June 2021, the clinical data of 18 CS patients who were hospitalized in Peking Union Medical College Hospital and diagnosed by pathology or by clinical and imaging features were collected. The general data, clinical manifestations, laboratory examination (white blood cell count, hemoglobin, etc.), imaging features (ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI)), and diagnosis and treatment of the patients were retrospectively analyzed. Descriptive method was used for statistical analysis.Results:The median age of 18 CS patients was 18 years old (ranged from 1 to 39 years old); there were 10 male and 8 female patients with a male-to-female ratio of 5∶4. The median time from symptom onset to diagnosis was 24 months (ranged from 1 month to 28 years). At the time of diagnosis, 15 patients had already had portal hypertension-related complications, and 8 patients had biliary infections. The common symptoms included abdominal distension (6 cases), fever with or without abdominal pain (5 cases), and loss of appetite (3 cases). The common abnormal laboratory findings included peripheral white blood cell count, hemoglobin level and platelet count below the normal reference value range, alanine aminotransferase and bilirubin level above the normal reference value range, and 4 patients had positive autoantibodies. Four patients were clearly diagnosed according to the pathology of liver biopsy, 14 patients were clearly diagnosed by imaging. Among which the diagnostic rate of abdominal ultrasonography for CS was 4/18, CT was 11/15, and MRI or magnetic resonance cholangiopancreatography was 12/16. The typical features of abdominal ultrasonography were liver cysts with splenomegaly, typical manifestation of CT was intrahepatic bile duct dilatation with " central dot sign", and MRI typically manifested as multiple cystic dilatations of intrahepatic bile ducts. Among the 18 patients with CS, 1 case underwent right hepatectomy, 3 cases were waiting for liver transplantation, and the other 14 patients chose symptomatic treatment due to economic reasons.Conclusions:The clinical manifestations and laboratory findings of CS patients lack specificity, and the diagnosis of most patients is delayed. The lack of understanding of the disease by clinical and imaging doctors may be one of the reasons affecting the early diagnosis of CS patients. The findings of splenomegaly and liver cysts by abdominal ultrasound may provide clues for the diagnosis of CS for clinical and imaging doctors.

Animals ; Cells, Cultured ; NAV1.8 Voltage-Gated Sodium Channel ; metabolism ; Pain ; chemically induced ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Rats ; Scorpion Venoms ; pharmacology ; Up-Regulation