ABSTRACT
In the original publication of the article, the representative EEG of female rat pups with FS in Figure 1 C and D was incorrectly intercepted from that of male rat pups. This correction does not affect the conclusions of the paper. Figure 1 has been corrected on the online PDF version and displayed below.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the modulatory effects of morphine on the susceptibility to pentylenetetrazole-induced seizures, and the involvement of endogenous histamine in this process.</p><p><b>METHODS</b>Both the wild-type (WT) mice and histidine decarboxylase (a key enzyme for histamine biosynthesis) deficient (HDC-KO) mice were subcutaneously injected with different doses of morphine, and 1 hour later the pentylenetetrazole solution (1.5 %) was infused into the tail vein at a constant rate of 0.3 ml/min. The minimal dose of pentylenetetrazole (mg/kg) needed to induce myoclonic jerks and clonus convulsion was recorded as the thresholds of seizures.</p><p><b>RESULT</b>In WT mice, morphine dose-dependently decreased the thresholds of both myoclonic jerks and clonus convulsion. In HDC-KO mice, morphine at 10 mg/kg only significantly decreased the threshold of myoclonic jerks from (38.6 +/-2.9)mg/kg to (32.5 +/-0.7)mg/kg, but had no significant effect on the threshold of clonus convulsion [from (51.8 +/-2.1)mg/kg to (47.6 +/-1.2)mg/kg]. In addition, the value of decreased myoclonic jerks (15.8 +/-1.4)% and clonus convulsion (8.3 +/-0.9)% thresholds were much lower in HDC-KO mice than in WT mice [(26.1 +/-2.5)% and (20.8 +/-2.4)%, respectively].</p><p><b>CONCLUSION</b>Morphine can decrease the thresholds of pentylenetetrazole in induction of seizure, and the endogenous histamine may be involved in this process.</p>
Subject(s)
Animals , Male , Mice , Disease Susceptibility , Metabolism , Dose-Response Relationship, Drug , Histamine , Metabolism , Physiology , Histidine Decarboxylase , Genetics , Metabolism , Mice, Knockout , Morphine , Pharmacology , Myoclonus , Metabolism , Narcotics , Pharmacology , Pentylenetetrazole , Random Allocation , Seizures , Genetics , Sensory ThresholdsABSTRACT
<p><b>OBJECTIVE</b>To investigate effects of acute maximal electroshock (MES) and chronic transauricular kindled seizures on learning abilities in Sprague-Dawley rats.</p><p><b>METHODS</b>An acute MES was induced by giving an alternating current (150 mA, 0.2 s) through ear-clip electrodes. Chronic transauricular kindled seizure was induced by repeated application of initially subconvulsive electrical stimulation (40 mA, 0.2 s) through ear-clip electrodes once every 24 h. An 8-arm radial maze (4 arms baited) was used to measure learning abilities. Histamine, glutamate and gamma-aminobutyric acid (GABA) were measured by high-performance liquid chromatography (HPLC).</p><p><b>RESULT</b>In the acquisition learning process, an acute MES increased reference memory errors but not working memory errors. In addition, it increased GABA levels in the hippocampus. On the other hand, chronic transauricular kindled seizures increased both working and reference memory errors in retrieval memory process, and this lasted for at least 3 weeks. Chronic transauricular kindled seizures induced CA1 neuron damage and a decrease in histamine levels in the hippocampus.</p><p><b>CONCLUSION</b>Different types of kindling seizure produce different effects on cognitive behavior: (1) an acute MES impairs learning ability, which may be associated with an abnormal plasticity and an increase of GABA in the hippocampus; (2) the chronic transauricular kindled seizure impairs retrieval memory mainly, which may be related to CA1 neuron damage and a decrease in histaminergic activity in the hippocampus.</p>