Effect of ramosetron, a 5-HT3 receptor antagonist on the severity of seizures and memory impairment in electrical amygdala kindled rats.

The entorhinal cortex (EC) plays a pivotal role in epileptogenesis and seizures. EC expresses high density of serotonergic receptors, especially 5-HT3 receptors. Cognitive impairment is common among people with epilepsy. The present study investigated the role of 5-HT3 receptor on the severity of seizures and learning and memory impairment by electrical kindling of amygdala in rats. The amygdala kindling was conducted in a chronic kindling manner in male Wistar rats. In fully kindled animals, ramosetron (as a potent and selective 5-HT3 receptor antagonist) was microinjected unilaterally (ad doses of 1, 10 or 100 µg/0.5 µl) into the EC 5 min before the novel object recognition (NOR) and Y-maze tests or kindling stimulations. Applying ramosetron at the concentration of 100 µg/0.5 µl (but not at 1 and 10 µg/0.5 µl) reduced afterdischarge (AD) duration and increased stage 4 latency in the kindled rats. Moreover, the obtained data from the NOR test showed that treatment by ramosetron (10 and 100 µg/0.5 µl) increased the discrimination index in the fully kindled animals. Microinjection of ramosetron (10 and 100 µg/0.5 µl) in fully kindled animals reversed the kindling induced changes in the percentage of spontaneous alternation in Y-maze task. The findings demonstrated an anticonvulsant role for a selective 5-HT3 receptor antagonist microinjected into the EC, therefore, suggesting an excitatory role for the EC 5-HT3 receptors in the amygdala kindling model of epilepsy. This anticonvulsive effect was accompanied with a restoring effect on cognitive behavior in NOR and Y-maze tests.

Platelet Indices and CXCL12 Levels in Patients with Intrauterine Growth Restriction.

BACKGROUND: Intrauterine growth restriction (IUGR) is a multifactorial condition, and the precise mechanism is still unknown. In the current study, we aimed to determine the relationship between the platelet (PLT) indices and CXC12 levels in patients with IUGR. PATIENTS AND MATERIALS: In this study, 36 patients with IUGR and 36 healthy pregnant mothers were enrolled as the case and control groups, respectively. Gestational age for both groups was between 24 and 40 years. Blood samples were taken, and platelet indices were examined by a full-diff cell counter. Serum levels of CXCL12 were measured by ELISA, and the data were analyzed using an independent Student's t-test. RESULTS: In this study, we observed that the mean value of PLT count (154.3 ± 50 vs 236 ± 36) and plateletcrit (0.124 ± 0.038 vs 0.178 ± 0.021) were significantly lower in the case than the control group. In contrast, the mean platelet volume (7.94 ± 0.55 vs 7.62 ± 0.53) and platelet distribution width (17.57 ± 0.7 vs 16.96 ± 0.59) were significantly higher in the case than the control group. More importantly, we found that the serum levels of CXCL12 were significantly higher (5.3 ng/mL± 3.1 vs 2.8 ± 1.6) in the patients compared to the pregnancy controls. CONCLUSION: Our data show that platelet indices are changed in IUGR, and the levels of circulating CXCL12 are increased in patients with IUGR. These findings provide a base for further studies to better defining the pathophysiology of IUGR.

Opioid Receptors Gene Polymorphism and Heroin Dependence in Iran.

INTRODUCTION: Genes often have multiple polymorphisms that interact with each other and the environment in different individuals. Variability in the opioid receptors can influence opiate withdrawal and dependence. In humans, A118G Single Nucleotide Polymorphisms (SNP) on µ-Opioid Receptor (MOR), 36 G>T in κ-Opioid Receptor (KOR), and T921C in the δ-Opioid Receptor (DOR) have been found to associate with substance dependence. METHODS: To investigate the association between opioid receptors gene polymorphism and heroin addiction, 100 control subjects with no history of opioid use, and 100 heroin addicts (50% males and 50% females) in Tehran (capital of Iran), were evaluated. A118G, 36 G>T, and T921C SNPs on the MOR, KOR, DOR genes, respectively, were genotyped by sequencing. RESULTS: We found no differences in either allele or genotype frequency for MOR, KOR and DOR genes SNPs between controls and subjects addicted to heroin. CONCLUSION: The relationships among polymorphisms may be important in determining the risk profile for complex diseases such as addiction, but opioid addiction is a multifactorial syndrome which is partially hereditary and partially affected by the environment.

Endocannabinoid CB1 receptors are involved in antiepileptogenic effect of low frequency electrical stimulation during perforant path kindling in rats.

INTRODUCTION: Administration of low-frequency electrical stimulation (LFS) at the kindling site has an antiepileptogenic effect. In the present study, we investigated the role of cannabinoid receptors type 1 (CB1) in mediating the inhibitory effects of LFS on the development of perforant path kindled seizures. METHODS: For seizure generation, rats were kindled by electrical stimulation of perforant path in semi-rapid kindling manner (12 stimulations per day at 10 min intervals at afterdischarge threshold intensity).To determine the effect of LFS (0.1 ms pulse duration at 1 Hz, 800 pulses) on seizure generation, LFS was applied to the perforant path 5 min after the last kindling stimulation daily. AM281, a CB1 receptor antagonist, was microinjected into the lateral ventricle immediately after the last kindling stimulation (before LFS application) at the doses of 0.5 and 2 µg/µl during kindling procedure. The expression of cannabinoid receptors in the dentate gyrus was also investigated using immunohistochemistry. RESULTS: Application of LFS had inhibitory effect on development of kindled seizures (kindling rate). Microinjection of AM281 (0.5 µg/µl) immediately after the last kindling stimulation (before LFS application) reduced the inhibitory effect of LFS on the kindling rate and suppressed the effects of LFS on potentiation (increasing the magnitude) of both population spike amplitude and population excitatory postsynaptic potential slope during kindling acquisition. AM281 pretreatment also prevented the effects of LFS on kindling-induced increase in early and late paired pulse depression. The higher dose of AM281 (2 µg/µl) failed to exert the effects observed with its lower dose (0.5 µg/µl). In addition, there was a decreased CB1 receptors immunostaining in kindled animals compared to control. However, application of LFS following kindling stimulations led to overexpression of CB1 receptors in the dentate gyrus. CONCLUSION: Obtained results showed that activation of overexpressed cannabinoid CB1 receptors by endogenous cannabinoids may have a role in mediating the inhibitory effect of LFS on perforant path kindled seizures.

ERK activation is required for the antiepileptogenic effect of low frequency electrical stimulation in kindled rats.

INTRODUCTION: The signaling pathways involved in the antiepileptogenic effect of low frequency electrical stimulation (LFS) have not been fully understood. In the present study the role of extracellular signal-regulated kinase (ERK) signaling cascade was investigated in mediating the inhibitory effects of LFS on kindled seizures. METHODS: Animals received kindling stimulations for seven days (the mean number of stimulation days for achieving stage 5 seizure) according to semi-rapid perforant path kindling protocol (12 stimulations per day at 10 min intervals). LFS (0.1 ms pulse duration at 1 Hz, 800 pulses) was applied at 5 min after the last kindling stimulation every day. During the kindling procedure, FR180204 (inhibitor of ERK) was daily microinjected (1 µg/µl; intracerebroventricular) immediately after the last kindling stimulation and before LFS application. The expression of activated ERK (p-ERK) in the dentate gyrus was also investigated using immunohistochemistry technique. RESULTS: Application of LFS at 5 min after the last kindling stimulation had inhibitory effect on kindling rate. FR180204 had no significant effect on seizure parameters when administered at the dose of 1 µg/µl in kindled group of animals. However, microinjection of FR180204 before LFS application reduced the inhibitory effect of LFS on seizure severity and field potential parameters (i.e. the slope of population field excitatory postsynaptic potentials and population spike amplitude) during kindling. FR180204 also blocked the preventing effects of LFS on kindling-induced increase in early (at 10-40 ms intervals) and late (at 300-1000 ms intervals) paired pulse depression. In addition, application of LFS following kindling stimulations increased the expression of p-ERK in the dentate gyrus. CONCLUSION: Obtained results showed ERK signaling pathway had important role in mediating the antiepileptogenic effect of LFS in perforant path kindling. These findings represent a promising opportunity to gain insight about LFS mechanism in epilepsy therapy.