ABSTRACT
Migraine is a neurological disorder characterized by recurrent and disabling severe headaches. Although several anticonvulsant drugs that block voltage-dependent Na⁺ channels are widely used for migraine, far less is known about the therapeutic actions of carbamazepine on migraine. In the present study, therefore, we characterized the effects of carbamazepine on tetrodotoxin-resistant (TTX-R) Na⁺ channels in acutely isolated rat dural afferent neurons, which were identified by the fluorescent dye DiI. The TTX-R Na⁺ currents were measured in medium-sized DiIpositive neurons using the whole-cell patch clamp technique in the voltage-clamp mode. While carbamazepine had little effect on the peak amplitude of transient Na⁺ currents, it strongly inhibited steady-state currents of transient as well as persistent Na⁺ currents in a concentration-dependent manner. Carbamazepine had only minor effects on the voltage-activation relationship, the voltage-inactivation relationship, and the use-dependent inhibition of TTX-R Na⁺ channels. However, carbamazepine changed the inactivation kinetics of TTX-R Na⁺ channels, significantly accelerating the development of inactivation and delaying the recovery from inactivation. In the current-clamp mode, carbamazepine decreased the number of action potentials without changing the action potential threshold. Given that the sensitization of dural afferent neurons by inflammatory mediators triggers acute migraine headaches and that inflammatory mediators potentiate TTX-R Na⁺ currents, the present results suggest that carbamazepine may be useful for the treatment of migraine headaches.
Subject(s)
Animals , Rats , Action Potentials , Anticonvulsants , Carbamazepine , Headache , Kinetics , Migraine Disorders , Nervous System Diseases , Neurons , Neurons, Afferent , Sodium Channels , Trigeminal GanglionABSTRACT
Objectives: The demand for mobile bathing service (MBS) is increasing in the Japanese society. Therefore, we assessed the risk of MBS-associated infection in MBS clients and their caregivers by examining the bacterial colonization of MBS equipment and utensils. Methods: Bacterial isolates collected by the stamp agar culture method were examined by disk diffusion assay for their susceptibility to the following drugs: imipenem, ciprofloxacin, amikacin, azutreonam, ceftazidim, meropenem, piperacillin, tobramycin, ofloxacin and cefoperazone. Furthermore, these isolates were subtyped by SpeI-pulsed field gel electrophoresis (SpeI-PFGE). Results: Fifty-four P. aeruginosa isolates were recovered from different sampling sites, and of these, 26 (47.3%) were isolated from pillows. Eighteen isolates (33.3%) were imipenem (IPM) resistant. The minimum inhibitory concentrations (MICs) of 17 isolates were between 16 and 32 μg/ml, and the MIC of one isolate was greater than 32 μg/ml. The SpeI-PFGE typing of IPM-resistant isolates revealed that 13 of the 18 isolates were closely related (F=1.0−0.87). Conclusion: Our findings suggest that MBS equipment and utensils, particularly pillows, are the primary sources of bacterial contamination and transmission and that there is a risk of MBS-mediated infection among MBS clients and their caregivers.
Subject(s)
Risk , Imipenem , Electrophoresis, Gel, Pulsed-Field , Pseudomonas aeruginosaABSTRACT
<p><b>OBJECTIVES</b>The demand for mobile bathing service (MBS) is increasing in the Japanese society. Therefore, we assessed the risk of MBS-associated infection in MBS clients and their caregivers by examining the bacterial colonization of MBS equipment and utensils.</p><p><b>METHODS</b>Bacterial isolates collected by the stamp agar culture method were examined by disk diffusion assay for their susceptibility to the following drugs: imipenem, ciprofloxacin, amikacin, azutreonam, ceftazidim, meropenem, piperacillin, tobramycin, ofloxacin and cefoperazone. Furthermore, these isolates were subtyped bySpeI-pulsed field gel electrophoresis (SpeI-PFGE).</p><p><b>RESULTS</b>Fifty-fourP. aeruginosa isolates were recovered from different sampling sites, and of these, 26 (47.3%) were isolated from pillows. Eighteen isolates (33.3%) were imipenem (IPM) resistant. The minimum inhibitory concentrations (MICs) of 17 isolates were between 16 and 32 μg/ml, and the MIC of one isolate was greater than 32 μg/ml. TheSpeI-PFGE typing of IPM-resistant isolates revealed that 13 of the 18 isolates were closely related (F=1.0-0.87).</p><p><b>CONCLUSION</b>Our findings suggest that MBS equipment and utensils, particularly pillows, are the primary sources of bacterial contamination and transmission and that there is a risk of MBS-mediated infection among MBS clients and their caregivers.</p>