Improvement of fertility parameters with tribulus terrestris and anacyclus pyrethrum treatment in male rats

ABSTRACT Objective Anacyclus Pyrethrum (AP) and Tribulus Terrestris (TT) have been reported as male infertility treatment in several studies; however, in Iranian traditional medicine these two plants are prescribed simultaneously. In this study, we aimed to determine the effects of AP and TT extracts both separately and simultaneously on the male Wistar rat fertility parameters. Materials and Methods 32 male Wistar rats were divided into 4 groups: Control, TT, AP, and AT treated groups. Treatment continued for 25 days and rats were weighed daily. Their testes were dissected for histological studies. Sperm analysis including sperm count, viability and motility were performed. Serum was obtained to evaluate testosterone, LH and FSH levels. Histological studies were conducted to study Leydig, and Sertoli cells, spermatogonia and spermatid cell numbers, and to measure seminiferous diameter and epithelium thickness. Results Sperm count increased in all the treatment groups. Sperm viability and motility in AT and AP groups were elevated. TT and AT groups showed significantly increased testosterone level compared to control group (P=004, P=0.000, respectively) and TT, AP and AT treatment groups showed increased LH level (P=0.002, P=0.03 and P=0.000, respectively) compared to control, while only AT group showed increased FSH (p=0.006) compared to control. Histological studies showed significant increase of spermatogonia, Leydig and Sertoli cell numbers and epithelial thickness in AT group compared to other groups. All the treatment groups had higher number of Leydig, spermatogonia and spermatid cells. Conclusion TT and AP improved sexual parameters; however, their simultaneous administration had higher improving effects on studied parameters.

Effect of different loads of exercise and Nigella sativa L. seed extract on serologic and hematologic parameters in rat

There are many recommendations for prophylactic usage of Nigella sativa L. for healing fatigue and body strengthening. However, a scientific and standard method for diagnosis and management of overtraining in athletes has not been introduced. Here, we studied the effect of different loads of exercise and N. sativa treatment on serologic and hematologic parameters in rat was examined. Male Wistar rats were divided into control sedentary (C), moderate trained (MT), overtrained (OT), control sedentary + N. sativa (NC), moderate trained + N. sativa (NM) and overtrained + N. sativa (NO) treatment. Animals’ performances were evaluated before and during the study. Immediately, 24 h and two weeks after the last bout of exercise serum concentration of corticosterone and lactate as well as total and differential WBC, RBC, Hb, Hct, corpuscular indices and platelets were also measured. Increasing training load caused a significant performance decline in OT and OR groups (P <0.01-P <0.001). Compared to control group, serum corticosterone and lactate concentrations were significantly increased after moderate exercise and overtraining (P <0.05 to P <0.001), total WBC count (P 0.001), lymphocytes (P <0.01) and monocytes (P <0.01) were decreased in overtraining animal. N. sativa treatment caused a significant decrease in lactate concentration in overtraining (P <0.01) and serum corticosterone in all exercised (P <0.05) compared to untreated groups. Overtraining induced chronic inflammatory like changes, performance decline, stress hormone elevation, and WBC count decrement. N. sativa administration improved corticosterone elevation and metabolic state.

Thymoquinone reverses learning and memory impairments and brain tissue oxidative damage in hypothyroid juvenile rats / Timoquinona protegeu contra deficiências de aprendizagem e memória e danos nos tecidos cerebrais em ratos hipotireoidais juvenis

ABSTRACT In this study, the effect of thymoquinone (TQ) on propylthiouracil (PTU)-induced memory impairment was investigated in juvenile rats. The rats were grouped into control, Hypo, Hypo-TQ5 and Hypo-TQ10. Propylthiouracil increased latency time in the Morris water maze test and decreased delay in entering the dark compartment in the passive avoidance test. Both 5 mg/kg and 10 mg/kg doses of TQ decreased latency time in the Morris water maze test and increased delay in entering the dark compartment in a passive avoidance test. The PTU also increased malondialdehyde and nitric oxide metabolites in the brain while reduced the thiol content and superoxide dismutase and catalase activities and serum T4 level. Both doses of TQ decreased malondialdehyde and nitric oxide metabolites in the brain while enhanced the thiol content and superoxide dismutase and catalase activities and serum T4 level. The results of the present study showed that TQ protected against PTU-induced memory impairments in rats.

RESUMO Neste estudo, foi investigado o efeito da timoquinona (TQ) contra deficiências de memória induzidas por propiltiouracilo (PTU) em ratos juvenis. Os ratos foram agrupados em grupos: controle, Hypo, Hypo-TQ5, e Hypo-TQ10. O PTU aumentou o tempo de latência no teste do labirinto aquático de Morris (MWM) e diminuiu o atraso para entrar no compartimento escuro no teste de evasão passiva (PA). Ambas as doses de TQ diminuíram o tempo de latência no teste de MWM e aumentaram o atraso para entrar no compartimento escuro no teste de PA. O PTU também aumentou os metabolitos de malondialdeído (MDA) e óxido nítrico (NO) no cérebro, enquanto reduziu o teor de tiol e as atividades de superóxido dismutasa (SOD) e catalasa (CAT) e o nível sérico de T4. Ambas as doses de TQ diminuíram os metabolitos de MDA e de NO no cérebro, aumentaram o conteúdo de tiol e as atividades de SOD e CAT e o nível de T4 no soro. Os resultados do presente estudo mostraram que a TQ protegeu contra deficiências de memória induzidas por PTU em ratos.

Lipopolysaccharide-induced memory impairment in rats is preventable using 7-nitroindazole / O déficit de memória induzido por lipossacarídeos em ratos é prevenido por nitroindazol

Inflammation and oxidative stress have important roles in memory impairment. The effect of 7-nitroindazole (7NI) on lipopolysaccharide (LPS)-induced memory impairment was investigated. Rats were used, divided into four groups that were treated as follows: (1) control (saline); (2) LPS; (3) 7NI-LPS; and (4) 7NI before passive avoidance (PA). In the LPS group, the latency for entering the dark compartment was shorter than in the controls (p < 0.01 and p < 0.001); while in the 7NI-LPS group, it was longer than in the LPS group (p < 0.01 and p < 0.001). Malondialdehyde (MDA) and nitric oxide (NO) metabolite concentrations in the brain tissues of the LPS group were higher than in the controls (p < 0.001 and p < 0.05); while in the 7NI-LPS group, they were lower than in the LPS group (p < 0.001 and p < 0.05, respectively). The thiol content in the brain of the LPS group was lower than in the controls (p < 0.001); while in the 7NI-LPS group, it was higher than in the LPS group (p < 0.001). It is suggested that brain tissue oxidative damage and NO elevation have a role in the deleterious effects of LPS on memory retention that are preventable using 7NI.

Inflamação e estresse oxidativo tem importante papel no déficit de memória. O efeito do 7-nitroindazol (7NI) no déficit de memória induzido por lipossacarídeos (LPS) foi investigado. Foram utilizados ratos que foram divididos em quatro grupos e tratados da seguinte maneira: (1) controles (solução salina); (2) LPS; (3) 7NI-LPS; e (4) 7NI antes da esquiva passiva (PA). No grupo LPS, a latência para entrar no compartimento escuro foi mais curta que nos controles (p < 0,01 e p < 0,001); enquanto no grupo 7NI-LPS, a latência foi maior que aquela do grupo LPS (p < 0,01 e p < 0,001). Concentrações de malondialdeído (MDA) e metabólitos do ácido nítrico (NO) no tecido cerebral do grupo LPS foram maiores que aquelas dos controles (p < 0,001 e p < 0,05); enquanto no grupo 7NI-LPS, as concentrações foram menores do que no grupo LPS (p < 0,001 e p < 0,05, respectivamente). O conteúdo cerebral de tiol no grupo LPS foi menos do que nos controles (p < 0,001); enquanto no grupo 7NI-LPS, este conteúdo foi maior que no grupo LPS (p < 0,001). Sugere-se que o dano oxidativo cerebral e o aumento de NO tenham um papel nos efeitos deteriorativos dos LPS na memória de retenção, e que isto possa ser prevenido com o uso de 7NI.

Tamoxifen antagonizes the effects of ovarian hormones to induce anxiety and depression-like behavior in rats / Tamoxifeno antagoniza os efeitos dos hormônios ovarianos que induzem comportamento similar a ansiedade e depressão em ratos

The effects of tamoxifen (TAM) on anxiety and depression-like behavior in ovariectomized (OVX) and naïve female rats were investigated. The animals were divided into Sham-TAM, OVX-TAM, Sham and OVX groups. Tamoxifen (1 mg/kg) was administered for 4 weeks. In the forced swimming test, the immobility times in the OVX and Sham-TAM groups were higher than in the Sham group. In the open field, the numbers of central crossings in the OVX and Sham-TAM groups were lower than the number in the Sham group, and the number of peripheral crossings in the OVX group was lower than the number in the Sham group. In the elevated plus maze, the numbers of entries to the open arm among the animals in the Sham-TAM and OVX groups were lower than the number in the Sham group, while the number of entries to the open arm in the OVX-TAM group was higher than the number in the OVX group. It was shown that deletion of ovarian hormones induced anxiety and depression-like behavior. Administration of tamoxifen in naïve rats led to anxiety and depression-like behavior that was comparable with the effects of ovarian hormone deletion. It can be suggested that tamoxifen antagonizes the effects of ovarian hormones. It also seems that tamoxifen has anxiolytic effects on ovariectomized rats.

Foram investigados os efeitos do tamoxifeno (TAM) no comportamento semelhante a ansiedade de depressão de ratas ooforectomizadas (OVX) e controles. Os animais foram divididos em Sham-TAM, OVX-TAM, Sham e OVX groups. Tamoxifeno (1 mg/kg) foi administrado por quatro semanas. No teste de natação forçada, os tempos de imobilidade nos grupos OVX e Sham-TAM foram maiores que aqueles do grupo Sham. No campo aberto, os números de cruzamento no centro nos grupos OVX e Sham-TAM foram menores que aquele do grupo Sham, e o número dos cruzamentos na periferia no grupo OVX foi menor que o número no grupo Sham. No labirinto elevado, os números de entradas com braços abertos entre os animais nos grupos Sham-TAM e OVX foram menores do que aqueles do grupo Sham, enquanto o número de entradas com os braços abertos no grupo OVX-TAM foi maior que aquele no grupo OVX. Foi observado que a deleção dos hormônios ovarianos induziu comportamento similar a ansiedade e depressão. A administração de tamoxifeno em ratos controle induziu a um comportamento que era comparável aos efeitos da deleção do hormônio ovariano. Pode ser sugerido que o tamoxifeno antagoniza os efeitos dos hormônios ovarianos. Parece também que o tamoxifeno tem efeito ansiolítico nas ratas ooforectomizadas.

Antioxidant effect of achillea wilhelmsii extract on pentylenetetrazole (seizure model)-induced oxidative brain damage in wistar rats.

An important role for oxidative stress both as a consequence and as a cause of epileptic seizures has been suggested. Since Achillea wilhelmsii (A. wilhelmsii) has been considered to have the antioxidant effects as well as central nervous system depressant properties, the anti-seizure effects of the plant extract in addition to its effects on brain tissues oxidative damage were investigated in pentylenetetrazole (PTZ)-induced seizures model. Male Wistar rats were divided into 5 groups: (1) Control, (2) PTZ, (3-5) A. wilhelmsii extract groups (AWE). The animals in groups 2-5 were treated with saline or AWE (100, 200 or 400 mg/kg) before single injection of PTZ (90 mg/kg). Latency to first minimal clonic seizure (MCS) and the first generalized tonic-clonic seizures (GTCS) were recorded. The brain tissues were then removed for biochemical measurements. MCS latencies in extract treated groups were not different from PTZ group. The animals treated by 200 mg/kg of AWE had a significant higher GTCS latency in comparison with PTZ group (P<0.001). The MDA levels in PTZ group were significantly higher and the total thiol concentrations were lower than control animals. Pretreatment with all 3 doses of the extract resulted in a significant reduction in the MDA levels (P<0.05, P<0.01 and P<0.001) and a significant elevation in total thiol concentration, as compared with PTZ group (P<0.05 and P<0.01). The present study showed that the hydroalcoholic extract of A. wilhelmsii possesses an antioxidant effect in the brain in PTZ induced seizure model.

Brain tissue oxidative damage as a possible mechanism for the deleterious effect of a chronic high dose of estradiol on learning and memory in ovariectomized rats / Dano oxidativo ao tecido cerebral como possível mecanismo de efeito deletério da alta dose crônica de estradiol no aprendizado e memória de ratas ooforectomizadas

In addition to antioxidative effects, estrogens also exert pro-oxidative actions. The effect of chronic administration of a high dose of estradiol valerate on Morris water maze tasks and brain tissues oxidative damage was investigated. The Sham-Est and OVX-Est groups were treated with estradiol valerate (4 mg/kg) for 12 weeks. Escape latency and traveled path in the Sham-Est and OVX-Est groups were significantly higher than in the Sham and OVX groups (p≪0.01 and p≪0.001). In the probe trial, the animals of the Sham-Est and OVX-Est groups spent lower time in Q1 compared to Sham and OVX groups (p≪0.05 and p≪0.001). In Sham-Est and OVX-Est groups, the brain tissue total thiol concentration was significantly lower, and malondialdehyde (MDA) concentrations were higher than in the Sham and OVX groups (p≪0.05 and p≪0.001). It is concluded that administration of high exogenous levels of estradiol impairs performance and enhances oxidative stress.

Além dos efeitos antioxidantes, os estrógenos também têm ação pró-oxidativa. Foi investigado o efeito da administração crônica de alta dose de valereato de estradiol no desempenho do labirinto aquático de Morris e o dano oxidativo ao tecido cerebral. Os grupos Sham-Est e OVX-Est foram tratados com valereato de estradiol (4 mg/kg) por 12 semanas. O tempo de latência para escapada e o caminho percorrido foram significativamente maiores nos grupos Sham-Est e OVX-Est em relação aos grupos Sham e OVX (p≪0,01 e p≪0,001). No estudo probe, os animais dos grupos Sham-Est e OVX-Est levaram menos tempo no Q1 em comparação aos grupos Sham e OVX (p≪0,05 e p≪0,001). Nos grupos Sham-Est e OVX-Est, a concentração total de tiol foi significativamente menor, enquanto a concentração de malondialdehydo (MDA) for maior do que aquela dos grupos Sham e OVX (p≪0,05 e p≪0,001). Concluiu-se que a administração de altas doses de estradiol exógeno compromete o desempenho e aumenta o estresse oxidativo naqueles animais.

Effect of inhaled fluticasone and salmeterol on tracheal responsiveness and lung inflammation: Influence of administration time and allergen-free period.

Background: The effect of inhaled fluticasone propionate (FP) and salmeterol (SM) on tracheal responsiveness (TR) to methacholine and lung pathology of sensitized guinea pig was examined. Materials and Methods: Six groups of guinea pigs (n = 7) were sensitized to ovalbumin (OA). Three groups were subjected to inhaled FP and SM, one group during (A), one group after sensitization (for 18 days, B) and other group during sensitization but with 18-days delay before measurements (C). Other three groups were treated with placebo. Results: The TR to methacholine and tracheal muscle contractility were significantly higher than those of control group (P < 0.001 for all cases). The lungs of placebo groups showed variable pathological changes (nonsignificant to P < 0.001) compared to control group. TR, intra-alveolar and interabronchoal hemorrhagie (P < 0.001 in only group A) in treated groups with FP and SM were significantly decreased compared to placebo groups. The improvement in all variables in treatment groups A and C were more pronounced than group B. Conclusion: These results showed a protective effect of FP and SM on tracheal responsiveness and lung pathology during sensitization which was more effective than after sensitization.

Decreased nitric oxide levels in the hippocampus may play a role in learning and memory deficits in ovariectomized rats treated by a high dose of estradiol / Níveis diminuídos de óxido nítrico no hipocampo podem ser importantes nos déficits de aprendizado e de memória em ratas ooforectomizadas tratadas com alta dose de estradiol

The effects of a high estradiol dose on memory and on nitric oxide metabolites in hippocampal tissues were investigated. Sham-Est and OVX-Est Groups were treated with 4 mg/kg of estradiol valerate for 12 weeks. Time latency and path length were significantly higher in the Sham-Est and OVX-Est Groups than in the Sham and OVX Groups, respectively (p<0.001). The animals in the Sham-Est and OVX-Est Groups spent lower time in the target quadrant (Q1) than those of the Sham and OVX Groups during the probe trial test (p<0.05 and <0.001, respectively). Significantly lower nitric oxide metabolite levels in the hippocampi of the Sham-Est and OVX-Est Groups were observed than in the Sham and OVX ones (p<0.001). These results suggest that decreased nitric oxide levels in the hippocampus may play a role in the learning and memory deficits observed after treatment with a high dose of estradiol, although the precise underlying mechanisms remain to be elucidated.

Os efeitos de uma alta dose de estradiol na memória e nos metabólitos do óxido nítrico de tecidos hipocampais foram estudados. Os Grupos Sham-Est e OVX-Est foram tratados com 4 mg/kg de valerato de estradiol por 12 semanas. O tempo de latência e o comprimento do caminho foram significativamente maiores nos Grupos Sham-Est e OVX-Est em relação aos Grupos Sham e OVX, respectivamente (p<0,001). Os animais dos Grupos Sham-Est e OVX-Est passaram menos tempo na meta do quadrante (Q1) do que aqueles dos Grupos Sham e OVX durante o teste inicial (p<0,05 e <0,001, respectivamente). Níveis significativamente menores de metabólitos do óxido nítrico foram observados nos hipocampos dos Grupos Sham-Est e OVX-Est em relação aos Grupos Sham e OVX (p<0,001). Esses resultados sugerem que os níveis diminuídos de óxido nítrico no hipocampo podem ter um papel nos déficits de aprendizado e de memória, que são observados após tratamento com alta dose de estradiol, embora os mecanismos específicos envolvidos nestes achados ainda precisam ser elucidados.

Different effects of scopolamine on learning, memory, and nitric oxide metabolite levels in hippocampal tissues of ovariectomized and Sham-operated rats / Diferentes efeitos da escopolamina no aprendizado, na memória e nos níveis dos metabólitos do óxido nítrico no tecido hipocampal de ratas ooforectomizadas e controles operadas sem ooforectomia

Different effects of scopolamine on learning, memory, and nitric oxide (NO) metabolites in hippocampal tissues of ovariectomized (OVX) and sham-operated rats were investigated. The animals in the Sham-Scopolamine (Sham-Sco) and OVX-Scopolamine (OVX-Sco) Groups were treated with 2 mg/kg scopolamine before undergoing the Morris water maze, while the animals in the Sham and OVX Groups received saline. The time latency and path length were significantly higher in both the Sham-Sco and the OVX-Sco Groups, in comparison with the Sham and OVX Groups, respectively (p<0.001). Significantly lower NO metabolite levels in the hippocampi of the Sham-Sco Group were observed, compared with the Sham Group (p<0.001), while there was no significant difference between the OVX-Sco and OVX Groups. The decreased NO level in the hippocampus may play a role in the learning and memory deficits induced by scopolamine. However, it seems that the effect of scopolamine on hippocampal NO differs between situations of presence and absence of ovarian hormones.

Diferentes efeitos da escopolamina no aprendizado, na memória e nos níveis dos metabólitos do óxido nítrico (ON) no tecido hipocampal de ratas ovariectomizadas (OVX) e controles com cirurgia sem ooforectomia (Grupo Sham) foram investigados. Os animais dos grupos Sham-Escopolamina (Sham-Sco) e OVX-Escopolamina (OVX-Sco) foram tratados com escopolamina 2 mg/kg antes de entrar no labirinto aquático de Morris, enquanto aqueles dos grupos Sham e OVX receberam solução salina. A latência de tempo e o comprimento do caminho foram significativamente maiores nos Grupos Sham-Sco e OVX-Sco em comparação com os grupos Sham e OVX, respectivamente (p<0,001). Foram observados níveis significativamente mais baixos de metabólitos do ON nos hipocampos do Grupo Sham-Sco em comparação aos níveis do Sham (p<0,001), enquanto não foi observada diferença significativa entre os Grupos OVX-Sco e OVX. A diminuição do nível de ON no hipocampo pode ter um papel no aprendizado e nos déficits de memória induzidos pela escopolamina. No entanto, parece que este efeito da escopolamina no ON hipocampal é diferente em situações de presença ou ausência de hormônios ovarianos.

Effects of different extracts of Eugenia caryophyllata on pentylenetetrazole-induced seizures in mice / 中西医结合学报

To investigate the possible anticonvulsant effect of different extracts of Eugenia caryophyllata (clove) on pentylenetetrazole (PTZ)-induced seizures in mice.

Estrogen-dependent effect of soy extract on pentylenetetrazole-induced seizures in rats / 中西医结合学报

To study the different effects of soy extract on pentylenetetrazole (PTZ)-induced seizures in the presence and absence of ovarian hormones in rats, and the gender-dependent differences in the effects of phytoestrogens on behavior.

Chronic treatment with the nitric oxide synthase inhibitor, L-NAME, attenuates estradiol-mediated improvement of learning and memory in ovariectomized rats

INTRODUCTION: The role of ovarian hormones and nitric oxide in learning and memory has been widely investigated. OBJECTIVE: The present study was carried out to evaluate the effect of the nitric oxide synthase (NOS) inhibitor, N (G)-nitro-L-arginine methyl ester (L-NAME), on the ability of estradiol to improve learning in OVX rats using the Morris water maze. METHODS: Forty rats were divided into five groups: (1) ovariectomized (OVX), (2) ovariectomized-estradiol (OVX-Est), (3) ovariectomized-L-NAME 10 (OVX-LN 10), (4) ovariectomized-L-NAME 50 (OVX-LN 50) and (5) ovariectomized-estradiol-L-NAME 50 (OVX-Est-LN 50). The animals in the OVX-Est group were treated with a weekly injection of estradiol valerate (2 mg/kg; i.m.). The OVX-LN 10 and OVX-LN 50 groups were treated with daily injections of 10 and 50 mg/kg L-NAME (i.p.), respectively. The animals in the OVX-Est-LN 50 group received a weekly injection of estradiol valerate and a daily injection of 50 mg/kg L-NAME. After 8 weeks, all animals were tested in the Morris water maze. RESULTS: The animals in the OVX-Est group had a significantly lower latency in the maze than the OVX group (p<0.001). There was no significant difference in latency between the OVX-LN 10 and OVX-LN 50 groups in comparison with the OVX group. The latency in the OVX-Est-LN 50 group was significantly higher than that in the OVX-Est group (p<0.001). CONCLUSION: These results show that L-NAME treatment attenuated estradiol-mediated enhancement of spatial learning and memory in OVX rats, but it had no significant effect in OVX rats without estrogen, suggesting an interaction of nitric oxide and estradiol in these specific brain functions.

Effects of different extracts of Rosa damascena on pentylenetetrazol-induced seizures in mice / 中西医结合学报

In the present study, the effects of aqueous, ethanolic and chloroformic extracts of Rosa damascena on pentylenetetrazol (PTZ)-induced seizures were investigated in mice.

Effects of soy extract on pentylenetetrazol-induced seizures in ovariectomized rats / 中西医结合学报

Objective: To investigate the effects of soy extract on pentylenetetrazol (PTZ)-induced seizures in ovariectomized (OVX) rats. Methods: Female Wistar rats were randomly divided into 4 groups (n=15 in each group) as follows: sham-operated, OVX, low-dose soy (LDS) and high-dose soy (HDS). The rats in each group were divided into two subgroups and received daily injection of a low dose of PTZ (40 mg/kg body weight, intraperitoneally, n=7 in each subgroup) for 14 d or a single injection of a high dose of PTZ (90 mg/kg body weight, intraperitoneally, n=8 in each subgroup). The rats of LDS and HDS groups were injected with 20 and 60 mg/kg body weight of soy extract intraperitoneally, respectively, just 30 min before each PTZ injection. The rats of the sham-operated and the OVX groups received saline instead of soy extract. After treatment, the rats were placed in a plexiglas cage and their behaviors were observed for 60 min. Results: The results of repeated injection of low dose of PTZ during 14 d showed that the seizure score of the rats of OVX group on days 3, 5, 8, 10, 11, 12, and 13 was lower than that of the sham-operated group (P<0.05 or P<0.01). However, the rats of both LDS and HDS groups had higher score compared with the OVX group on the mentioned days (P<0.05 or P<0.01). The results of a single injection of a high dose of PTZ showed a significant increase (P<0.01) in the generalized tonic-clonic seizure (GTCS), but not the minimal clonic seizure (MCS) in the OVX rats compared with the sham-operated rats. Treatment with both low and high doses of soy extract significantly decreased the GTCS and MCS latencies compared with the OVX group (P<0.01). Conclusion: Female hormones affect seizure severity induced by PTZ, and phytoestrogens of soy mimic this effects. However, more investigations need to be done in the future.

The effect of chronic administration of L-arginine on the learning and memory of estradiol-treated ovariectomized rats tested in the morris water maze

OBJECTIVE: The present study was carried out to evaluate the effect of L-arginine on the learning and memory of estradiol-treated ovariectomized (OVX) rats. METHODS: Forty-eight rats were divided into six groups: (1) sham, (2) OVX, (3) sham-Est, (4) OVX-Est, (5) sham-Est-LA, and (6) OVX-Est-LA. The animals of the sham-Est and OVX-Est groups were treated by weekly injection of estradiol valerate (2mg/kg). The sham-Est-LA and OVX-Est-LA groups were treated in the same manner but with an additional daily injection of L-arginine (200mg/kg). After eight weeks, animals of all groups were tested in the Morris water maze. The escape latency and path traveled to reach the platform were compared between groups. RESULTS: Time latency and path length in the OVX group were significantly higher than in the sham group (P<0.05). The OVX-Est group had a significantly shorter traveled path length and time latency compared to the OVX group (P<0.001). Time latency and path length in the sham-Est group was significantly higher than in the sham group (P<0.001). Time latency and path length in the OVX-Est-LA group were significantly higher than in the OVX-Est group. CONCLUSIONS: These results allow us to propose that chronic treatment with estradiol enhances the spatial learning and memory of OVX rats, and that long term L-arginine treatment attenuates the effects of improvement produced by estradiol in OVX rats.

Nitric oxide contributes to learning and memory deficits observed in hypothyroid rats during neonatal and juvenile growth

INTRODUCTION: Severe cognitive impairment follows thyroid hormone deficiency during the neonatal period. The role of nitric oxide (NO) in learning and memory has been widely investigated. METHODS: This study aimed to investigate the effect of hypothyroidism during neonatal and juvenile periods on NO metabolites in the hippocampi of rats and on learning and memory. Animals were divided into two groups and treated for 60 days from the first day of lactation. The control group received regular water, whereas animals in a separate group were given water supplemented with 0.03 percent methimazole to induce hypothyroidism. Male offspring were selected and tested in the Morris water maze. Samples of blood were collected to measure the metabolites of NO, NO2, NO3 and thyroxine. The animals were then sacrificed, and their hippocampi were removed to measure the tissue concentrations of NO2 and NO3. DISCUSSION: Compared to the control group's offspring, serum thyroxine levels in the methimazole group's offspring were significantly lower (P<0.01). In addition, the swim distance and time latency were significantly higher in the methimazole group (P<0.001), and the time spent by this group in the target quadrant (Q1) during the probe trial was significantly lower (P<0.001). There was no significant difference in the plasma levels of NO metabolites between the two groups; however, significantly higher NO metabolite levels in the hippocampi of the methimazole group were observed compared to controls (P<0.05). CONCLUSION: These results suggest that the increased NO level in the hippocampus may play a role in the learning and memory deficits observed in childhood hypothyroidism; however, the precise underlying mechanism(s) remains to be elucidated.

Effects of angiotensin II and captopril on rewarding properties of morphine.

The effects of captopril and Ang II on morphine-induced conditioned place preference (CPP) and morphine self-administration in male Wistar rat were investigated. In CPP experiment, injection of captopril before test significantly decreased the difference of the time spent in compartment A between pre- and post-conditioning compared to morphine group. In self- administration experiment number of active lever pressing was significantly greater than passive in morphine group. In captopril group number of active lever pressing was significantly lower than morphine group however, there was not significant difference between active and passive lever pressed number. The results showed that captopril significantly decreased morphine-induced conditional place preference and morphine self-administration but the effect of Ang II was not significant. It can be concluded that RAS may have a role in rewarding properties of morphine.