Effects of amygdala kindled seizures on memory retention of passive-avoidance test in rats / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effects of amygdala kindled seizures on memory retention of passive-avoidance test in rats.</p><p><b>METHODS</b>Chronic kindled seizures were achieved by daily application of electric stimulations on amygdala until the occurrence of 3 consecutive convulsive seizures. Then a passive-avoidance test was performed to measure memory retention ability in rats; another group of rats received an electric stimulation on amygdala 5 min before the training trail to observe the effects of acute seizure attack on memory retention ability.</p><p><b>RESULT</b>In the training trail and the 1st day of the test trail, there was no difference in the latency to enter dark compartment between chronic kindled seizure group and its corresponding control group. However, the latency significantly increased at the 5 th day of test trail. In addition, the latency of acute seizure attack group rats significantly decreased at the 1 st day and 5 th day of test trail.</p><p><b>CONCLUSION</b>Chronic amygdala kindled seizures increase memory retention of passive-avoidance test in rats, and acute seizure attack impairs this action.</p>

Involvement of endogenous histamine in modulatory effect of morphine on seizure susceptibility in mice / 浙江大学学报·医学版

<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>

Injection of saline into unilateral central piriform cortex inhibits amygdaloid-kindled seizures in rats / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effect of microinjection of saline into unilateral central piriform cortex (cPC) on the generalized seizures in amygdaloid-kindled rats.</p><p><b>METHODS</b>Different volumes of saline were injected into the right or left cPC of amygdaloid-kindled rats, and its effect on generalized seizures was observed.</p><p><b>RESULT</b>Saline injection at different volumes 0.1 microl, 0.25 microl and 1 microl) significantly decreased the incidence and duration of generalized seizures (P<0.05), the anticonvulsant effect lasted for up to 10 d. In addition, 10 min after ipsilateral injection of saline the generalized seizure thresholds were significantly increased; while this effect was observed 30 min later when contralateral injection was used.</p><p><b>CONCLUSION</b>Unilateral saline injection into cPC has a significant anticonvulsant effect, which might be used for treatment of human temporal lobe epilepsy in the future.</p>