Evaluation of the effect of Exercise Trainings and CGRP receptor antagonist (BIBN 4096) on mitochondrial dynamic in the hippocampus of male Wistar rats

BACKGROUND

Exercise training showed beneficial effects on brain. The purpose of the present study is to evaluate the effect of six weeks of high-intensity interval training (HIIT) and Endurance training (ET) with calcitonin gene-related peptide (CGRP) receptor antagonist on the expression of genes involved in mitochondrial dynamics and apoptosis in hippocampal tissue of male Wistar rats.

METHODS

In this study, forty-two healthymale Wistar rats (8-week) were randomly divided into 6 groups (n = 7) as follow; 1) Control; 2) HIIT which performed 6 weeks of HIIT; 3) ET which performed 6 weeks of endurance training; 4) CGRPi received 10 mg/kg CGRP receptor antagonist every day at the last 2 weeks; 5) CGRPi-HIIT performed HIIT and received CGRP receptor antagonist; 6) CGRPi-ET performed ET and received CGRP receptor antagonist. Real-time PCR (2-ΔΔCT) and western blotting were employedto measure the expression of genes and protein, respectively.

RESULTS

HIIT and ET significantly increased Bcl-2, Pgc-1α, Sirt3, and Nrf-1 gene expression in the hippocampal tissue (p < 0.05, p < 0.01, p < 0.01, and p < 0.001, respectively). ET-CGRPi and HIIT-CGRPi significantly increased Sirt3, Pgc-1α, and Nrf-1 gene expression compared to the control group (p < 0.05, p < 0.01, and p < 0.05, respectively).

CONCLUSION

ET and HIIT-induced physiological alterations in the hippocampus. In fact, this modulation showed protective properties in the hippocampusvia up regulation of Bcl-2, Pgc-1α, Nrf-1, and Sirt3 gene expression. CGRPi did not cause gene or protein changes harmful to mitochondrial dynamic balance and apoptosis in the hippocampus of rats.

Moderate Endurance Training and MitoQ Improve Cardiovascular Function, Oxidative Stress, and Inflammation in Hypertensive Individuals: The Role of miR-21 and miR-222: A Randomized, Double-Blind, Clinical Trial

OBJECTIVE

Hypertension (HTN) is among the leading causes of myocardial infarction, stroke, and kidney disease. The MitoQ supplement is a mitochondrial-targeted antioxidant that attenuates the generation of reactive oxygen species (ROS). miRNAs play an essential role in the pathophysiology of HTN. Regular aerobic exercise is recommended to decrease the risk of cardiovascular disease. We aimed to evaluate the effects of MitoQ supplementation and moderate endurance training (ET), alone and in combination, on cardiac function, blood pressure, the circulatory levels of miRNA-21 and miRNA-222, and oxidative status in individuals with HTN.

MATERIALS AND METHODS

In a double-blind, randomized clinical trial (except for ET group), 52 male hypertensive subjects (40-55 years old) were randomly divided into four groups (n=13): Placebo, MitoQ (20 mg/day, oral), ET (Cycle ergometer, moderate intensity, 40-60% VO2 peak, three sessions/week for six weeks), and MitoQ+ET. Cardiac echocardiography indices, serum oxidative and inflammation status, and miRNAs 21 and 222 were assessed before and after interventions.

RESULTS

Left ventricular mass [effect size (ES): -6.3, 95% confidence interval (CI): -11.2 to -1.4] and end-systolic/ diastolic diameters significantly improved in the intervention groups (ES: -0.05, 95% CI: -0.11 to 0.00 and -0.09, 95% CI: -0.16 to -0.02). Total serum antioxidant capacity (TAC) increased (ES: 36.0, 95% CI: 26.1 to 45.8), and malondialdehyde (MDA) (ES: -0.43, 95% CI: -0.53 to -0.32), IL-6 (ES: -1.6, 95% CI: -1.98 to -1.25), miR-21 (ES: -0.48, 95% CI: -0.61 to -0.35), and miR-222 (ES: -0.31, 95% CI: -0.44 to -0.18) significantly decreased in response to ET, MitoQ, and their combination.

CONCLUSION

MitoQ and ET, individually and more pronouncedly in combination, can improve cardiovascular health in people with high blood pressure (BP) by reducing inflammation and increasing antioxidant defense, in association with reduction in circulatory miR-21 and miR-222 levels (registration number: IRCT20190228042870N1).

Effects of short environmental enrichment on early-life adversity induced cognitive alternations in adolescent rats

Early-life experiences, including parental care, affect cognitive performance later in life. Being exposed to early-life maternal separation (MS) increases susceptibility to stress-related psychopathology. Previous studies suggest that MS could induce learning and memory impairments. Since enriched environment (EE) provides more opportunities for exploration and social interaction, in the present study we evaluated the effects of a short EE paradigm with a duration of 13 days on cognitive abilities of maternally separated rats (MS; 180 min/day, postnatal day (PND) 1-21) during adolescence in four experimental groups: Control, Control+EE, MS, and MS+EE. Plasma corticosterone (CORT) and brain-derived neurotrophic factor (BDNF) levels were also measured in experimental animals. We also studied the induction of long-term potentiation (LTP) in the slices of hippocampal CA1 area. The behavioral and electrophysiological assessments were started at PND 35. MS caused higher basal CORT levels in plasma and impaired spatial learning, memory, and social interaction. LTP induction was also impaired in MS rats and plasma BDNF levels were reduced in these animals. MS also induced more anxiety-like behavior. Short EE reduced plasma CORT levels had the potential to improve locomotor activity and anxiety-like behavior in MS+EE rats and reversed MS-induced impairments of spatial learning, memory, and social behavior. LTP induction and plasma BDNF levels were also enhanced in MS+EE rats. We concluded that short EE might be considered as a therapeutic strategy for promoting cognition.

Interaction of high-intensity endurance exercise and nandrolone on cardiac remodeling: role of adipo-cardiac axis

OBJECTIVES

Given the cardiac pathological remodeling following to anabolic androgenic steroids (AASs) consumption, we examined the effect of chronic administration of nandrolone decanoate with high-intensity endurance exercise on the left ventricular hypertrophy index, levels of hydroxyproline, tumor necrosis factor-alpha (TNF-α), adiponectin (APN) and its receptors (AdipoR1 and AdipoR2) expression in rats' hearts.

METHODS

The male Wistar rats randomly divided to six groups included the control (CTL), exercise (Ex), nandrolone (Nan), vehicle (Arach), trained vehicle (Ex + Arach), and trained nandrolone (Ex + Nan) groups that were treated for eight weeks.

RESULTS

Nandrolone consumption significantly enhanced the hypertrophy index (p<0.05) and exercise intensified this effect. It also increased the level of cardiac hydroxyproline (p<0.001), however exercise completely masked this effect. The values of TNF-α protein and AdipoR1 protein significantly increased in trained nandrolone-treated (Ex + Nan) group in comparison with CTL group (p<0.05), however, did not show significant alteration in Nan or Ex groups. High-intensity endurance exercise significantly enhanced the AdipoR2 protein (p<0.05), but, co-administration of nandrolone with exercise prevented this effect. The mRNA expression of AdipoR1 significantly reduced in the animals that received nandrolone for eight weeks and exercise recovered this effect (p<0.001).

CONCLUSIONS

Despite an additive effect of high-intensity endurance exercise plus nandrolone on TNF-α level, their effects on hydroxyproline and APN receptors expression is incompatible in heart of rat. It is suggests a part of beneficial regulatory role of endurance exercise against nandrolone induced heart remodeling may apply through modulation of APN system.

SIRT1 and Klotho expression in the heart and kidneys of rats with acute and chronic renovascular hypertension

Aim

To evaluate Klotho and SIRT1 expression in the heart and kidneys of rats with acute and chronic renovascular hypertension.

Methods

Four and sixteen weeks after the induction of renovascular hypertension by clipping the left renal artery, systemic blood pressure, serum angiotensin II level, and the expression of Klotho and SIRT1 proteins and oxidative stress indices in the heart and kidneys were assessed.

Results

SIRT1 level was significantly reduced in the ischemic (left) kidney in acute and chronic phases of hypertension. In the heart, it decreased in the acute phase, but increased in the chronic phase. Klotho levels in the heart and kidneys did not change significantly in either hypertension phase. Superoxide dismutase (SOD) activity in the heart significantly decreased, and SOD, total antioxidant capacity, and malondialdehyde in the ischemic kidney significantly increased during the development of hypertension. Serum angiotensin II level significantly increased in the acute phase of hypertension.

Conclusion

Development of renovascular hypertension was associated with a reduction of SIRT1 expression in the heart and ischemic kidney. As angiotensin II and SIRT1 counteract each other's expression, a SIRT1 reduction in the heart and kidney, along with the influence of systemic/local angiotensin II, seems to be partly responsible for hypertension development. A combination of SIRT1 agonists and angiotensin II antagonists may be considered for use in the treatment of renovascular hypertension.

Serum microRNA-33 levels in pre-diabetic and diabetic patients

Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and abnormal insulin secretion. MicroRNAs are small, non-coding RNAs that are able to affect cell biological functions and act as biomarkers for some diseases such as DM. In current study, we measured serum miR-33 in three groups (n = 15) as follows; non-diabetic control, pre-diabetic, and DM patients. Real-time PCR method was used to quantify miR-33 expression. miR-33 expression was significantly increased in pre-diabetic subjects compared to other two groups (p < 0.001). FBS (p < 0.001), insulin (p < 0.001), HOMA-IR (p < 0.001), and TG (p = 0.026) were higher in diabetic subjects than the other two groups. In people that had high physical activity, the number of diabetic subjects were zero and most of them were in pre-diabetic group (p = 0.019). Serum miR-33 level significantly and positively correlated with pre-diabetic state (B = 2.67, p = 0.000), Sex (B = 1.03, p = 0.025), and FBS (B = 0.04, p = 0.036) and also miR-33 was significantly and negatively correlated with HOMA-IR (B = - 1.58, p = 0.04). These findings support the possible role of miR-33 to monitor pre-diabetes onset and progression. It needs to be evaluated in future studies with high number of participants to clarify its mechanism and diagnostic viability.

Electromagnetic field protects against cognitive and synaptic plasticity impairment induced by electrical kindling in rats

Kindling results in abnormal synaptic potentiation and significant impairment in learning and memory. Electromagnetic field (EMF) effects on learning and memory in kindled animals and its effects on hippocampal neural activity are largely unknown. In the current study, the effects of EMF on learning and memory, as well as hippocampal synaptic plasticity, in kindled rats were investigated. EMF (10 mT; 100 Hz) was applied to fully kindled animals one hour/day for a period of one week. The behavioral and electrophysiological studies were performed 24 h following the EMF application. The kindled rats showed spatial learning deficits during the training phase of the Morris water maze (MWM) test. Moreover, there were increments in escape latency and path length compared to the sham group. The kindled rats spent less time in the target-quadrant probe test, indicating spatial memory impairment. Applying EMF to the KEMF group (kindling + EMF) restored learning and memory, and decreased escape latency and path length significantly compared to the kindled group. EMF alone had no significant effects on the learning and memory parameters. Based on the open field (OF) test results, EMF alone in the EMF group, but not in the kindled or the KEMF groups, decreased the total traveled distance and increased the spent time in the peripheral zone, compared to the sham group. Based on electrophysiological results, applying EMF in the KEMF group returned the ability of synaptic potentiation to the hippocampal CA1 area and high-frequency stimulation induced long-term potentiation (LTP). Accordingly, EMF can be considered a potential therapy for seizure-induced deficits in learning and memory.

Effect of 4-Fluoro-N-(4-sulfamoylbenzyl) Benzene Sulfonamide on cognitive deficits and hippocampal plasticity during nicotine withdrawal in rats

Withdrawal from chronic nicotine has damaging effects on a variety of learning and memory tasks. Various Sulfonamides that act as carbonic anhydrase inhibitors have documented role in modulation of various cognitive, learning, and memory processing. We investigated the effects of 4-Fluoro-N-(4-sulfamoylbenzyl) Benzene Sulfonamide (4-FBS) on nicotine withdrawal impairments in rats using Morris water maze (MWM), Novel object recognition, Passive avoidance, and open field tasks. Also, Brain-derived neurotrophic factor (BDNF) profiling and in vivo field potential recording were assessed. Rats were exposed to saline or chronic nicotine 3.8 mg/kg subcutaneously for 14 days in four divided doses, spontaneous nicotine withdrawal was induced by quitting nicotine for 72 h (hrs). Animals received 4-FBS at 20, 40, and 60 mg/kg after 72 h of withdrawal in various behavioral and electrophysiological paradigms. Nicotine withdrawal causes a deficit in learning and long-term memory in the MWM task. No significant difference was found in novel object recognition tasks among all groups while in passive avoidance task nicotine withdrawal resulted in a deficit of hippocampus-dependent fear learning. Anxiety like behavior was observed during nicotine withdrawal. Plasma BDNF level was reduced during nicotine withdrawal as compared to the saline group reflecting mild cognitive impairment, stress, and depression. Withdrawal from chronic nicotine altered hippocampal plasticity, caused suppression of long-term potentiation (LTP) in the CA1 area of the hippocampus. Our results showed that 4-FBS at 40 and 60 mg/kg significantly prevented nicotine withdrawal-induced cognitive deficits in behavioral as well as electrophysiological studies. 4-FBS at 60 mg/kg upsurge nicotine withdrawal-induced decrease in plasma BDNF. We conclude that 4-FBS at 40 and 60 mg /kg effectively prevented chronic nicotine withdrawal-induced impairment in long term potentiation and cognitive performance.

Impact of extremely low-frequency electromagnetic field (100 Hz, 100 G) exposure on human glioblastoma U87 cells during Temozolomide administration

Glioblastoma multiforme (GBM) is a highly malignant brain tumor with an extremely dismal prognosis, a median survival is12 months. Temozolomide (TMZ) is an alkylating agent widely used to treat cancer, resistance to this drug is often found. One unexplored possibility for overcoming this resistance is a treatment based on concomitant exposure to electromagnetic fields (EMF) and TMZ. Indeed, many evidences show that EMF affects cancer cells and drug performance. Therefore, the present study was carried out to evaluate the potential synergistic effect of 100 µM TMZ and EMF (100 Hz, 100 G) on human glioma cell line U87 U87 cells with four experimental groups (I-IV) were exposed to ELF-EMF and TMZ for 120 and 144 h, as follows: (I) control; (II) ELF-EMF; (III) TMZ; (IV) ELF-PEMFs / TMZ. mRNA expression of genes such as (Nestin,CD133, Notch4 and GFAP) were investigated by Real-time PCR and western blot. We also evaluated, SOD activity, MDA and calcium concentration by ELISA assay. Co-treatment synergistically decreased the expression of Nestin,CD133, and Notch4 and increased the GFAP genes. We also observed an increase in Superoxide dismutase (SOD) activity, Malondialdehyde (MDA) and Ca2+concentration in comparison to controls.TMZ prevents cancer progression not only through the induction of cell death, but also by inducing differentiation in cancer cells. In addition, our data demonstrate ELF-EMF (100 Hz, 100 G) can significantly enhance the effects of TMZ on human glioblastoma U87 cell. These findings may open new window for future studies.

Anti-inflammatory and anti-remodeling effects of myrtenol in the lungs of asthmatic rats: Histopathological and biochemical findings

INTRODUCTION

Asthma is a chronic inflammatory disease of the airways. In this study, we evaluated the anti-inflammatory effects of myrtenol on the inflammatory indices in the pulmonary parenchyma and airways and on the inflammatory and oxidative indices of the bronchoalveolar lavage fluid (BALF) of asthmatic rats.

METHODS

The allergic asthma was induced by sensitization (two weeks) followed by the inhalation of ovalbumin (four weeks). Animals were divided into two main groups: (1) Histopathology, and (2) measurement of inflammatory and oxidative biomarkers in the BALF. Each main group was subdivided into four subgroups: Control, Asthma, Asthma+Dexamethasone and Asthma+Myrtenol. (-)-Myrtenol (50mg/kg) or Dexamethasone (2.5mg/kg) was administered intraperitoneally once a day for one week, at the end of the inhalation period. On day 50, lung histopathologic parameters and inflammatory indices in BALF including INF-γ, IL-10, IL-1β, and TNF-α and oxidative stress biomarkers (MDA, SOD, and GPX) were measured.

RESULT

In the Asthma group, leukocyte infiltration, the thickness of smooth muscle and epithelium of airways wall and the number of goblet cells increased. Myrtenol reduced all of the above-mentioned indices except the epithelium thickness. It also inhibited the increase in BALF IL-1β, TNF-α and MDA and increased the levels of INF-γ, IL-10 and SOD.

CONCLUSION

Our results suggest that myrtenol reduced damage caused by experimental asthma by reducing the inflammatory indices, normalizing the level of interleukins and balancing oxidative stress in the lungs. It also prevented airway remodeling. Myrtenol may be suggested as a potent herbal medicine for the treatment of allergic asthma.

The effect of different digoxin concentrations on heart tissue and antioxidant status in iron-overloaded rats

BACKGROUND

Thalassaemia is a hereditary disorder and has an economic burden on patients and the government. The most prevalent complication in these patients is iron overload which is followed by cardiomyopathy. Digoxin is considered as a treatment against heart failure in thalassaemia. The present study evaluated the effect of two digoxin concentrations on iron content and antioxidative defense in cardiac tissue of iron-overloaded rats.

METHODS

The study was conducted on 48 rats which were divided into 6 groups. Group 1 was the control group and did not receive any treatment and group 2 was the iron overload group. In addition groups 3 and 4 were the digoxin control groups which received 1 and 5 mg/kg/day of digoxin, respectively. Groups 5 and 6 received 1 and 5 mg/kg/day of digoxin plus iron-dextran, respectively. After 1 month, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPX), and total antioxidant status (TAS) were assessed in cardiac tissues.

RESULTS

Co-administration of iron-dextran and digoxin (1 and 5 mg/kg/day) significantly increased SOD and TAS levels (P < 0.0010) and reduced MDA (P < 0.0010) in heart tissue compared to control and iron overload groups. GPX levels significantly reduced in groups 5 and 6 (iron + digoxin 1 (P < 0.0500) and iron + digoxin 5) (P < 0.0010) compared to the iron control group.

CONCLUSION

Digoxin remarkably facilitates iron uptake by cardiomyocytes by affecting other channels such as L-type and T-type Ca2+ channels (LTCC and TTCC). Digoxin administration in the iron-overloaded rat model deteriorated antioxidative parameters and increased iron entry into heart tissue at higher doses. Therefore, in patients with beta thalassaemia major, digoxin must be administered with great care and serum iron and ferritin must be regularly monitored.

Low-intensity endurance exercise plus nandrolone decanoate modulates cardiac adiponectin and its receptors

Vast adverse effects of anabolic-androgenic steroids (AASs) on athletes' cardiovascular systems have been reported. However, there is still a lack of adequate information regarding the pathways and mechanisms involved. We tested the hypothesis that adiponectin and its receptors in the heart may be affected by long-term use of AASs alongside exercising. Male Wistar rats were randomized into the control (CTL), exercise (EX), nandrolone (Nan), arachis (Arach) group which treated with arachis as vehicle, trained vehicle (EX+Arach) and trained nandrolone (EX+Nan) groups that were treated for 8 weeks. One day after the end of the protocol, animals were sacrificed and their hearts were frozen. TNF-α and adiponectin proteins of hearts were evaluated quantitatively by ELISA kits, and Western blot analysis was used for measuring adiponectin receptor protein expression. TNF-α protein increased significantly in the EX+Nan group (P<.05 vs CTL group). The AdipoR1 protein was significantly higher in the presence of nandrolone alongside exercise (P<.05 vs Nan and EX+Arach groups, P<.01 vs CTL and Arach groups). In addition, AdipoR2 protein enhanced in the EX+Nan group when compared with the other groups (P<.05 vs EX and EX+Arach groups, P<.01 vs CTL, Arach and Nan groups). Chronic nandrolone plus mild endurance exercise may be associated with imbalance in pro-/anti-inflammatory cytokines and may induce a positive modulatory effect on cardiac adiporeceptors in rat. Further studies are required before these findings can be generalized to humans.

The effect of Elettaria cardamomum extract on anxiety-like behavior in a rat model of post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a debilitating psychiatric condition which develops in 6-8% of the general population. Current standard pharmacological treatments for PTSD cannot be widely used due to having various side effects. Nowadays, various pharmacological properties have been related to Elettaria cardamomum L. (family of Zingiberaceae). The present study aims to evaluate the efficacy of E. cardamomum methanolic extract on anxiety-like behavior in a rat model of PTSD. Adult male Wistar rats (200-250gr) were used in this study. The rats underwent single prolonged stress (SPS) or control and intraperitoneally received either saline or different dosages (200, 400, and 800mg/kg) of E. cardamomum methanolic extract before and after stress sessions. Moreover, open field, elevated plus-maze, and rotarod tests were used to evaluate locomotion and anxiety-like behavior in the rats. Findings demonstrated that E. Cardamomum methanolic extract, particularly at the dose of 400mg/kg, significantly (P<0.05) improved anxiety-like behavior in a rat model of PTSD, as examined by the open field, elevated plus-maze, and rotarod tests. Administration of E. cardamomum methanolic extract after stress might help to prevent the formation of anxiety-like behavior in the animals. However, further studies are requiredto clarify the exact mechanisms involved.

Chemical Composition, Anticonvulsant Activity, and Toxicity of Essential Oil and Methanolic Extract of Elettaria cardamomum

Elettaria cardamomum is an aromatic spice (cardamom) native to the humid Asian areas, which contains some compounds with a potential anticonvulsant activity. Various pharmacological properties such as anti-inflammatory, analgesic, antioxidant, and antimicrobial effects have been related to this plant. This research was conducted to examine the probable protective impact of the essential oil and methanolic extract of E. cardamomum against chemically (pentylentetrazole)- and electrically (maximal electroshock)-induced seizures in mice. In addition, neurotoxicity, acute lethality, and phytochemistry of the essential oil and methanolic extract were estimated. The TLC method showed the presence of kaempferol, rutin, and quercetin in the extract, and the concentration of quercetin in the extract was 0.5 µg/mL. The major compounds in the essential oil were 1,8-cineole (45.6 %), α-terpinyl acetate (33.7 %), sabinene (3.8 %), 4-terpinen-4-ol (2.4 %), and myrcene (2.2 %), respectively. The extract and essential oil showed significant neurotoxicity in the rotarod test at the doses of 1.5 g/kg and 0.75 mL/kg, respectively. No mortalities were observed up to the doses of 2 g/kg and 0.75 mL/kg for the extract and essential oil. The essential oil was effective in both the pentylentetrazole and maximal electroshock models; however, the extract was only effective in the pentylentetrazole model. The study suggested that E. cardamomum methanolic extract had no significant lethality in mice. Both the essential oil and methanolic extract showed movement toxicity. Anticonvulsant effects of E. cardamomum were negligible against the seizures induced by pentylentetrazole and maximal electroshock.

Effects of digoxin on cardiac iron content in rat model of iron overload

BACKGROUND

Plasma iron excess can lead to iron accumulation in heart, kidney and liver. Heart failure is a clinical widespread syndrome. In thalassemia, iron overload cardiomyopathy is caused by iron accumulation in the heart that leads to cardiac damage and heart failure. Digoxin increases the intracellular sodium concentration by inhibition of Na+/K+-ATPase that affects Na+/Ca2+ exchanger (NCX), which raises intracellular calcium and thus attenuates heart failure. The mechanism of iron uptake into cardiomyocytes is not exactly understood.

METHODS

We assessed the effect of different concentrations of digoxin on cardiac iron content in rat model of iron overload. Digoxin had been administrated intraperitoneally (IP) for one week before main study began to assure increased digoxin levels. Group 1 received four IP injections of iron-dextran (12.5mg/100g body weight) every 5 days evenly distributed over 20 days. Groups 2-4 received 0.5, 1 and 5 mg/kg/day IP digoxin, respectively. Last three groups 5-7 received iron-dextran as group 1 and digoxin concentrations 0.5, 1 and 5 mg/kg/day, respectively.

RESULTS

Cardiac iron contents were significantly higher in iron overload groups that received different concentrations (0.5, 1 and 5 mg/kg/day) of digoxin than their counterparts in control groups and this pattern was also observed in pathology assessment.

CONCLUSION

It seems that digoxin plays an important role in iron transport into heart in iron overload state but exact mechanism of this phenomenon is not clear. L-type Ca2+ channels are good candidates that probably could be involved in iron accumulation in cardiomyocytes. Thus it would be better to reconsider digoxin administration in thalassemia and iron overload conditions.

Comparing the anticonvulsant effects of low frequency stimulation of different brain sites on the amygdala kindling acquisition in rats

Low frequency stimulation (LFS) is a potential alternative therapy for epilepsy. However, it seems that the anticonvulsant effects of LFS depend on its target sites in the brain. Thus, the present study was designed to compare the anticonvulsant effects of LFS administered to amygdala, piriform cortex and substantia nigra on amygdala kindling acquisition. In control group, rats were kindled in a chronic manner (one stimulation per 24 h). In other experimental groups, animals received low-frequency stimulation (8 packages at 100 s intervals, each package contained 200 monophasic square-wave pulses, 0.1 ms pulse duration at 1 Hz andAD threshold intensity) in amygdala, piriform cortex or substantia nigra 60 seconds after the kindling stimulation, the AD duration and daily seizure stages were recorded. The obtained results showed that administration of LFS in all three regions reduced electrical and behavioral parameters of the kindling procedure. However LFS has a stronger inhibitory effect on kindling development when applied in substantia nigra compared to the amygdala and piriform cortex which reinforce the view that the substantia nigra mediates a crucial role in amygdala-kindled seizures. LFS had also greater inhibitory effects when applied to the amygdala compared to piriform cortex. Thus, it may be suggested that antiepileptogenic effect of LFS depends on its target site and different brain areas exert different inhibitory effects on kindling acquisition according to the seizure focus.