Effect of silymarin on liver size and nonalcoholic fatty liver disease in morbidly obese patients: A randomized double-blind clinical trial.

Background: A large liver size is a factor that may increase the difficulty of bariatric surgery (BS) and unwanted complications. Some agents have been used to decrease the liver size before BS. Silymarin has been used as an antioxidant agent to improve liver function tests. This study was designed to evaluate the effects of silymarin on liver dimensions, function, and lipid profile. Materials and Methods: A double-blind randomized clinical trial was performed on 56 patients. The patients were divided into silymarin and placebo groups. Blood samples and sonographic examinations were taken from the patients before and 4 weeks after the administration of the silymarin or placebo. In the first group, 140 mg silymarin was prescribed every 8 h for 4 weeks, and the other group received placebo in the same way with the same tablet shape. After the completion of the 4-week treatment, laboratory tests and ultrasonography were carried out again. Results: Thirty-nine (69.6%) patients were female with a mean body mass index (BMI) of 46.2 kg/m2 and a mean age of 36.8 years. Most of the patients had a compliance of 80% and higher. The analysis did not show any significant difference in aspartate transaminase, alkaline transaminase, liver size, cholesterol, and triglyceride changes among the silymarin and placebo groups. BMI loss was slightly higher in the silymarin group although the difference was not statistically significant. Conclusion: The present findings show that silymarin administration for 4 weeks does not affect liver size and function, but further evaluations should be carried out on the subject.

Predictors for weight loss after Roux-en-Y gastric bypass: the trend and associated factors for weight loss.

BACKGROUND: Historically, Roux-en-Y gastric bypass (RYGB) has been considered the gold standard of bariatric surgery (BS). This procedure acts as a mixed restrictive and malabsorptive operation. METHODS:  This retrospective cohort study included 410 morbidly obese patients (BMI > 40 kg/m2 or BMI > 35 kg/m2 along with at least one major comorbidity) who underwent primary laparoscopic RYGB surgery from 2009 to 2015 by a single surgery team. The patients were 18 years and older with at least 12 months of follow-up. Total weight loss (%TWL) and comorbidity resolution were compared in short-term (12 months) and mid-term (12-60 months) follow-ups. The primary and secondary outcomes were evaluating the effect of Roux-en-Y on weight loss and control of comorbidities, respectively. RESULTS:  The mean ± SD age, weight, and BMI at surgery were 40.1 ± 10.58 years, 123.32 ± 19.88 kg, and 45.78 ± 5.54 kg/m2, respectively, and 329 (80%) were female, and 62 (15%) had T2DM. %TWL was significantly higher in T2DM patients 9 months postoperatively and after that. Patients with lower BMI (< 50 kg/m2) at surgery and non-diabetic patients had a significantly lower %TWL over a short- and long-term follow-up (P < 0.001). CONCLUSIONS: BS remains the most efficacious and durable weight loss treatment. However, a proportion of patients will experience insufficient weight loss following BS.

One anastomosis gastric bypass as a one-stage bariatric surgical procedure in patients with BMI ≥ 50 kg/m2.

In patients with BMI ≥ 50 kg/m2, it is difficult to select an appropriate procedure that can lead to optimum results. This study aims to evaluate mid-term weight loss outcomes in patients with BMI ≥ 50 kg/m2 following one anastomosis gastric bypass (OAGB) as a one-stage procedure. A prospective study was conducted on patients with BMI ≥ 50 kg/m2, aged 18 years and above who had undergone primary OAGB from January 2016 to February 2019 with at least two years follow-ups. A total of 197 patients with BMI ≥ 50 kg/m2 had underwent OAGB. The mean age was 38 years and the mean pre-operative BMI was 53.7 kg/m2. Mean EWL% were 63.7%, 67.8% and 66.2% at one, two and five years after OAGB respectively. The highest level of EWL% was 68.4%, which was achieved in the 18th month following OAGB. OAGB can be performed safely in patients with BMI ≥ 50 kg/m2 as a one-stage procedure with acceptable weight loss outcomes and remission of obesity associated medical problems.

Five-year outcomes of one anastomosis gastric bypass as conversional surgery following sleeve gastrectomy for weight loss failure.

The most accepted procedures as conversion for poor weight changes after sleeve gastrectomy (SG), are malabsorptive surgeries. This study was designed to evaluate the 5-year outcomes of One Anastomosis Gastric Bypass (OAGB) following SG due to weight loss failure and weight regain. From September 2014 to January 2017, totally 23 patients with a history of SG conversion to OAGB in terms of weight loss failure or weight regain who had completed their 5-year follow-ups were studied. Some obesity related co-morbidities containing type-2 diabetes (DM), hypertension (HTN), dyslipidemia, obstructive sleep apnea (OSA) and gastroesophageal reflux disease (GERD) were also investigated at 1, 2, 3 and 5 years after conversional surgery. All cases had remission/improvement in DM, DLP, HTN and OSA 1 year after conversional OAGB. Analysis showed statistically significant (P < 0.001) change in trend of BMI. Mean BMI before conversional surgery, at 1, 2, 3and 5 years were 46.3 ± 10.4, 34.5 ± 8.5, 34.1 ± 8.6, 35.7 ± 8.7 and 37.5 ± 11.6, respectively. Mean percent excess weight loss (%EWL) at 1, 2, 3 and 5 years was 51.6 ± 11.0, 52.9 ± 13.1, 45.5 ± 16.4 and 41.0 ± 18.0, respectively. Mean percent total weight loss (%TWL) at 1, 2, 3 and 5 years was 26.6 ± 5.9, 27.4 ± 7.2, 23.9 ± 9.2 and 20.9 ± 9.3, respectively. OAGB is an effective conversional procedure for insufficient weight loss and weight regain following failed SG and lead to satisfactory changes in obesity associated medical problems. The optimal weight loss results are obtained at 2-year follow-ups and these effects are then reduced.

Refractory hypoglycemia induced by a duodenal wall gastrointestinal stromal tumor: A case report.

BACKGROUND: Tumor-associated hypoglycemia can be caused by non-islet cell tumors including gastrointestinal stromal tumor (GIST) which is a rare paraneoplastic syndrome that leads to the release of insulin-like growth factor-2 (IGF-2). CASE PRESENTATION: We report the case of a 45-year old woman who was admitted to our hospital with refractory hypoglycemic episodes. We found normal serum insulin and c-peptide level and abdominal CT-scan showed a small duodenal wall lesion suggesting insulinoma. After tumor resection, hypoglycemia symptoms were recovered, but the pathological findings demonstrated the lesion was GIST. CONCLUSION: In a small gastrointestinal lesion with hypoglycemic symptoms we should consider IGF-II secreting GIST in addition to insulinoma.

Changes in gut microbial flora after Roux-en-Y gastric bypass and sleeve gastrectomy and their effects on post-operative weight loss.

Bariatric surgery affects gut microbial flora due to the anatomical and physiological changes it causes in the gastrointestinal tract. Understanding the interaction between the gut flora, the type of bariatric surgery and weight loss may help improve bariatric surgery outcomes. This study was designed to compare the effects of Roux-en-Y Gastric Bypass (RYGB) and Sleeve Gastrectomy (SG) on two main phyla of the gut microbiota in humans and evaluate their potential effect on weight changes. Thirty morbidly obese patients were divided into two groups and underwent laparoscopic SG or laparoscopic RYGB. The patients' weight changes and fecal samples were evaluated at baseline and 6 months after the surgery. A microbial flora count was carried out of the phyla Bacteroidetes and Firmicutes and Bacteroides Fragilis. Changes in the abundance of the flora and their correlation with weight loss were analyzed. After 6 months, the patients with a history of RYGB showed a significant decrease in stool Bacteroidetes while the reduction in the SG group was insignificant. Firmicutes abundance was almost unchanged following SG and RYGB. There was no significant change in Bacteroides Fragilis abundance in either of the two groups, but a positive correlation was observed between Bacteroides Fragilis and weight loss after SG and RYGB. Bariatric surgery can affect gut microbiota. It can be concluded that these changes are dependent on many factors and may play a role in weight loss.

Laparoscopic Roux-en-Y gastric bypass in intestinal non-rotation.

There are some incidental findings during bariatric surgery. Some of these findings may make the operation more challenging than routine surgery. Intestinal malrotation/non-rotation are rare congenital anomalies that may remain asymptomatic until bariatric surgery. Here we report a 30-year-old female patient with unknown intestinal congenital anomaly which was diagnosed during surgery and she underwent Roux-en-Y gastric bypass, which can be a challenging procedure in intestinal malrotation/non-rotation and conversion may be needed.

Recurrent Spontaneous Abortion (RSA) and Maternal KIR Genes: A Comprehensive Meta-Analysis.

Natural killer cells (NKs) are the most important cells in the fetomaternal immune tolerance induced through interaction of maternal killer-cell immunoglobulin-like receptors (KIR) and fetal human leucocyte antigens (HLA). Hence, we intend to perform a meta-analysis on the role of maternal KIR genes diversity in recurrent spontaneous abortion (RSA). The present paper is a meta-analysis of previous genetic association studies and our previous original study. The results showed that KIR3DL1 was a significantly protecting factor for RSA (p=0.044; OR=0.833 [0.698-0.995]; fixed effect model). KIR2DS2 (p=0.034; OR=1.195 [1.013-1.408]; fixed effect model) and KIR2DS3 (p=0.013; OR=1.246 [1.047-1.483]; fixed effect model) were significantly risk factors for RSA. For KIR2DS1 there was a high heterogeneity and publication bias. Briefly, the inhibitory gene KIR3DL1 was a protecting factor, and the activating genes KIR2DS2 and KIR2DS3 were risk factors for RSA. However, the effect sizes were not suitable. We suggest further studies on different causes of pregnancy loss, to find the role of KIR2DS1.

The effects of different fractions of Coriandrum sativum on pentylenetetrazole-induced seizures and brain tissues oxidative damage in rats.

OBJECTIVE: In the present work, the effects of different fractions of Coriandrum sativum (C. sativum), on pentylenetetrazole (PTZ)-induced seizures and brain tissues oxidative damage were investigated in rats. MATERIALS AND METHODS: The rats were divided into the following groups: (1) vehicle, (2) PTZ (90 mg/kg), (3) water fraction (WF) of C. sativum (25 and 100 mg/kg), (4) n-butanol fraction (NBF) of C. sativum (25 and 100 mg/kg), and (5) ethyl acetate fraction (EAF) of C. sativum (25 and 100 mg/kg). RESULTS: The first generalized tonic-clonic seizures (GTCS) latency in groups treated with 100 mg /kg of WF or EAF was significantly higher than that of PTZ group (p<0.01). In contrast to WF, the EAF and NBF were not effective in increasing the first minimal clonic seizure (MCS) latency. Malondialdehyde (MDA) levels in both cortical and hippocampal tissues of PTZ group were significantly higher than those of control animals (p<0.001). Pretreatment with WF, NBF, or EAF resulted in a significant reduction in the MDA levels of hippocampi (p<0.01 - p<0.001). Following PTZ administration, a significant reduction in total thiol groups was observed in the brain tissues (p<0.05). Pretreatment with WF and NBF significantly elevated thiol concentrations in cortical and hippocampal tissues, respectively (p<0.05). CONCLUSION: The present study showed that different fractions of C. sativum possess antioxidant activity in the brain and WF and EAF of this plant have anticonvulsant effects.

Effects of hydroalcoholic extract of Coriandrum sativum on oxidative damage in pentylenetetrazole-induced seizures in rats.

BACKGROUND: An important role for oxidative stress, as a consequence of epileptic seizures, has been suggested. Coriandrum sativum has been shown that have antioxidant effects. Central nervous system depressant effects of C. sativum have also been reported. In this study, the effects of hydroalcoholic extract of aerial parts of the plants on brain tissues oxidative damages following seizures induced by pentylenetetrazole (PTZ) was investigated in rats. METHODS: The rats were divided into five groups and treated: (1) Control (saline), (2) PTZ (90 mg/kg, i.p.), (3-5) three doses (100, 500 and 1000 mg/kg of C. sativum extract (CSE) before PTZ. Latencies to the first minimal clonic seizures (MCS) and the first generalized tonic-clonic seizures (GTCS) were recorded. The cortical and hippocampal tissues were then removed for biochemical measurements. RESULTS: The extract significantly increased the MCS and GTCS latencies (P < 0.01, P < 0.001) following PTZ-induced seizures. The malondialdehyde (MDA) levels in both cortical and hippocampal tissues of PTZ group were significantly higher than those of the control animals (P < 0.001). Pretreatment with the extract prevented elevation of the MDA levels (P < 0.010-P < 0.001). Following PTZ administration, a significant reduction in total thiol groups was observed in both cortical and hippocampal tissues (P < 0.050). Pre-treatment with the 500 mg/kg of the extract caused a significant prevention of decreased in total thiol concentration in the cortical tissues (P < 0.010). CONCLUSION: The present study showed that the hydroalcoholic extract of the aerial parts of C. sativum possess significant antioxidant and anticonvulsant activities.

Effects of the hydro-alcoholic extract of Nigella sativa on scopolamine-induced spatial memory impairment in rats and its possible mechanism.

OBJECTIVE: To evaluate the effect of Nigella sativa (NS) extract on memory performance and its possible mechanisms in scopolamine (Sco)-induced spatial memory impairment model using Morris water maze test. METHODS: Thirty-two male Wistar rats were randomly divided into four groups. The control group received saline instead of both NS extract and Sco. The Sco group was treated by saline for two weeks, and was injected by Sco (2 mg/kg, intraperitoneally) 30 min before each trail in Morris water maze test. Sco+NS 200 and Sco+NS 400 groups were daily treated by 200 or 400 mg/kg of NS (intraperitoneally) for two weeks, respectively, and were finally injected by Sco 30 min before Morris water maze test. The brains of animals were removed to determine the acetylcholinesterase (AChE) activity and oxidative stress criteria in cortical tissues. RESULTS: Time latency and path length in the Sco group were significantly higher than in the control group (P<0.01), while the Sco+NS 400 group showed a significantly shorter traveled path length and time latency compared with the Sco group (P<0.01). AChE activity in the cortical tissues of the Sco group was significantly higher than the control group (P<0.01), while AChE activity in the Sco+NS 200 and Sco+NS 400 groups was lower than the Sco group (P<0.01). Following Sco administration, malondialdehyde (MDA) concentrations were increased (P<0.01) in comparison with the control group, while cortical total thiol content decreased (P<0.01). Pretreatment with extracts caused a significant elevation in cortical total thiol content (P<0.01) and reduction in cortical MDA concentration (P<0.01) compared with the Sco group. CONCLUSIONS: Hydro-alcoholic extract of NS prevents Sco-induced spatial memory deficits and decreases the AChE activity as well as oxidative stress of brain tissues in rats. Our results support the traditional belief about the beneficial effects of NS in nervous system. Moreover, further investigations are needed for better understanding of this protective effect.

Protection against brain tissues oxidative damage as a possible mechanism for the beneficial effects of Rosa damascena hydroalcoholic extract on scopolamine induced memory impairment in rats.

OBJECTIVES: Hypnotic, analgesic, anticonvulsant, and antioxidant effects of Rosa damascena have been reported. This study, investigated the effect of R. damascena hydroalcoholic extract on memory performance in a scopolamine-induced memory impairment model. METHODS: The rats were divided into control group received just saline; scopolamine group was treated by saline for 2 weeks, but was injected by scopolamine 30 minutes before each trial in Morris water maze test; treatment groups (scopolamine + extract 50; Sco + Ext 50) and (scopolamine + extract 250; Sco + Ext 250) were daily treated by 50 and 250 mg/kg of R. damascena extract (2 weeks) and were finally injected by scopolamine before each trial in Morris water maze. The brains were removed for biochemical measurements. RESULTS: Time latency and path length in the scopolamine group were higher than control (P < 0.01 to <0.001). Both treatment groups showed shorter traveled distance and time latency compared with scopolamine group (P < 0.05 to <0.001). Time spent in target quadrant by scopolamine group was lower than control (P < 0.05), while Sco + Ext 250 group spent longer time in target quadrant than scopolamine group (P < 0.05). Malondialdehyde concentrations in hippocampal and cortical tissues of scopolamine group were higher, while thiol concentrations were lower than control ones (P < 0.001). Treatment by both doses of the extract decreased the malondialdehyde concentration, while increased the thiol concentration (P < 0.05 to <0.001). DISCUSSION: The results of this study showed that the hydroalcoholic extract of R. damascena prevents scopolamine-induced memory deficits. This finding suggests that memory improvement may be in part due to the antioxidant effects.

Joubert syndrome in three children in a family: a case series.

Joubert syndrome (JS) is a rare autosomal recessive central nervous system malformation characterized by hypoplasia of the cerebellar vermis, hypotonia and abnormal psychomotor development, along with altered respiratory pattern and various ophthalmologic features. Here, we describe three children with Joubert syndrome in a family that had almost similar presentations, including ataxia, developmental delay, mental retardation and ocular disorders. Prevalence of Joubert syndrome is about 1 in 100,000 live birth. It may be accompanied by other organs' disorders. The molar tooth sign is pathognomonic for joubert syndrome that is ascertained by brain MRI.

Estrogen-dependent effect of soy extract on pentylenetetrazole-induced seizures in rats.

OBJECTIVE: 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. METHODS: Male and female Wistar rats were randomly divided into nine groups with eight in each, namely, male-saline (M-saline), male-low-dose soy (M-LDS), male-high-dose soy (M-HDS), sham-saline (Sh-saline), sham-low-dose soy (Sh-LDS), sham-high-dose soy (Sh-HDS), ovariectomized-saline (OVX-saline), ovariectomized-low-dose soy (OVX-LDS) and ovariectomized-high-dose soy (OVX-HDS). The rats of groups 7 to 9 were ovariectomized under ketamine anesthesia. The rats of groups 2, 5 and 8 were treated by 20 mg/kg of soy extract while the animals of groups 3, 6 and 9 received 60 mg/kg of soy extract for two weeks. In groups 1, 4 and 7, saline was injected instead of soy extract. The animals were then injected by a single dose of PTZ (90 mg/kg body weight, intraperitoneally) and placed in a plexiglas cage and the latency to minimal clonic seizure (MCS) and generalized tonic-clonic seizure (GTCS) was recorded. RESULTS: Both MCS and GTCS latency in M-LDS and M-HDS groups was significantly lower than that in M-saline group (P<0.05 or P<0.01). Treatment for female sham rats by soy extract did not affect MCS and GTCS latency. The animals of OVX-LDS and OVX-HDS groups had lower MCS and GTCS latency in comparison with OVX-saline group (P<0.05 or P<0.01). CONCLUSION: It is concluded that the phytoestrogens of soy affect seizure severity induced by PTZ, but their effects are different in the presence or absence of ovarian hormones. However, further studies are necessary to be done.

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.

Different effects of L-arginine on morphine tolerance in sham and ovariectomized female mice.

OBJECTIVE: The roles of gonadal hormones and nitric oxide (NO) on the analgesic effects of morphine, tolerance to morphine, and their interactions have been widely investigated. In the present study, the effect of L-arginine (an NO precursor) on morphine tolerance in sham and ovariectomized (OVX) female mice was investigated. METHODS: Forty mice were divided into sham and OVX groups. On the first day, a hot plate test ((55±0.2) °C; cut-off 30 s) was carried out as a base record 15 min before injection of morphine (10 mg/kg, subcutaneously (s.c.)) and was repeated every 15 min after injection. The sham group was then divided into two subgroups: sham-tolerance-L-arginine (Sham-Tol-LA) and sham-tolerance-saline (Sham-Tol-Sal) which received either L-arginine 50 mg/kg (intraperitoneally (i.p.)) or saline 10 ml/kg (i.p.), respectively, three times in a day for three consecutive days. Morphine tolerance was induced in animals by injecting 30 mg/kg morphine (s.c.) three times/day for three days. This treatment was also used for OVX subgroups. On the fifth day, the hot plate test was repeated. The analgesic effect of morphine was calculated as the maximal percent effect (MPE). The results were compared using repeated measure analysis of variance (ANOVA). RESULTS: There was no significant difference in MPE between the OVX and sham groups. The MPEs in both the Sham-Tol-Sal and OVX-Tol-Sal groups were lower than those in both the sham and OVX groups (P<0.01). The MPE in the OVX-Tol-Sal group was greater than that in the Sham-Tol-Sal group (P<0.01). The MPE in the Sham-Tol-LA group was higher than that in the Sham-Tol-Sal group (P<0.01). However, there was no significant difference between the Sham-Tol-LA and sham groups or between the OVX-Tol-LA and OVX-Tol-Sal groups. CONCLUSIONS: The results of the present study showed that repeated administration of morphine causes tolerance to the analgesic effect of morphine. L-arginine could prevent tolerance to morphine but its effect was different in the presence of ovarian hormones.

The effect of chronic administration of L-arginine and L-NAME on morphine-induced antinociception in ovariectomized rats.

OBJECTIVE: The role of ovarian hormones and nitric oxide on morphine-induced antinociception and their interaction have been widely investigated. The results of previous study showed that nitric oxide synthase inhibition differently affects morphine-induced antinociception in male and female rats. The present study was carried out to evaluate the different effects of chronic administration of L-arginine (LA) and L-NAME (LN) on morphine-induced antinociception in ovariectomized (OVX) and naive female rats. MATERIALS AND METHODS: Sixty female rats were randomly divided into six groups (n = 10) as follows: (1) sham, (2) OVX, (3) sham-LA (4) sham-LN (5) OVX-LA, and (6) OVX-LN. The animals of sham-LA and OVX-LA groups received daily injection of 200 mg/kg LA (i.p.) during 6 weeks, while in sham-LN and OVX-LN groups, the animals were treated with 10 mg/kg LN (i.p.). The animals of sham and OVX groups received 2 ml/kg saline (i.p.) instead of LA and LN. Finally, all the animals were tested on the hot plate test (52 ± 0.2°C; cut-off time 80 seconds) for evaluating the antinociceptive effects of morphine. The hot plate test was performed as three base records with a 15-min interval before the injection of morphine (10 mg/kg; s.c.) following which it was repeated every 15 min after injection. Analgesic effect of morphine was quantified as maximal percent effect (MPE). Base reaction latency times (seconds) before the injection of morphine and MPE after the injection of morphine were compared using repeated-measure analysis of variance (ANOVA) followed by post-hoc Tukey's test. Differences were considered statistically significant when P < 0.05. RESULTS: Before injection of morphine, there was no significant difference observed between sham and OVX groups in three recorded base reaction latency times. The base reaction latency times in sham-LA group were significantly higher than those of sham group (P < 0.001). In sham-LN group, the base reaction latency times were nonsignificantly lower than those of sham group (P = 0.095). There was no significant difference between OVX-LA group and OVX group. In OVX-LN group, three base reaction latency times were nonsignificantly lower than those of OVX group (P = 0.077). MPE in sham-LN group was higher than that of sham group (P < 0.05); however, there was no significant difference between sham-LA and sham groups. CONCLUSION: It is concluded that NO has a role in pain perception and the analgesic effect of morphine. The effect of NO might be differing in the presence or absence of ovarian hormones, but further investigations need to be done.

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.