Opioid receptors mediate inotropic and depressor effects of apelin in rats with 2K1C‐induced chronic renovascular hypertension

Apelin receptors (APJ) cross‐talk with other G‐protein‐coupled receptors. However, the role of APJ interaction with opioid receptors (OPR) on the cardiovascular effects of apelin in hypertension is not clear. Renovascular hypertension was induced by placing a Plexiglas clip on the left kidney of rats. After 16 weeks, F13A (an APJ antagonist), naloxone (a general OPR inhibitor), and nor‐binaltorphimine dihydrochloride (nor‐BNI; a selective inhibitor of KOR) were given prior to injections of apelin at doses of 40 and 60 μg/kg. The arterial systolic/diastolic blood pressure and left ventricular contractility responses were then evaluated. The arterial systolic/diastolic blood pressure in sham and 2K1C rats was 110/71 mm Hg and 171/124 mm Hg, respectively. The hypotensive effects of apelin at both doses were inhibited by F13A and naloxone. Nor‐BNI completely inhibited the effects of apelin 40 on arterial pressure, and decreased the effects of 60 μg/kg. KOR inhibition also prevented the compensation for the decrease in the left ventricle +dp/dt max and ?dp/dt max caused by apelin 60. The simultaneous inhibition of OPR and APJ reduced arterial pressure and increased cardiac contractility. Findings showed that the OPR, particularly KOR, mediate the inotropic, lusitropic, and depressor effects of apelin. The interaction of the OPR and APJ augments the inotropic and vasodepressor effects of apelin. This interaction may have potential clinical applications in cardiac failure since opioids are currently used in the treatment of myocardial infarction and stroke, and apelin has been introduced as a potential therapeutic agent in cardiovascular complications.     

Canine Visceral Leishmaniasis in Boyer Ahmad District,Kohgiluyeh & Boyer Ahmad Province,Southwest of Iran

Background

Mediterranean type of visceral leishmaniasis (VL) is present in different parts of Iran. Several studies have identified dogs as the main reservoirs of the VL caused by Leishmania infantum in Iran and other Mediterranean regions. This study aimed to determine the seroprevalence of canine visceral leishmaniasis as animal reservoir host for human visceral leishmaniasis in Boyer Ahmad district in southwest of Iran.

Methods

A seroepidemiological study was carried out to determine the seroprevalence of canine visceral leishmaniasis (CVL) among ownership dogs by using direct agglutination test (DAT) in 23 of 182 villages of Boyer Ahmad district, during August 2009 to August 2010. One hundred and seventy serum samples from ownership dogs were selected by multi-stage cluster sampling in villages of Boyer Ahmad district. All samples were tested by DAT and anti-Leishmania antibodies titers at ≥ 1:320 was considered as positive.

Results

Of the 170 serum samples, 10% were positive by DAT at titers of 1:320 and higher. No statistical significant difference was found between male (10.7%) and female (8.3%) seroprevalence. The highest seroprevalence rate (15.1%) was observed among the ownership dogs of four to seven years age. Altogether, seventeen (25.4%) of the seropositive dogs had clinical signs and symptoms.

Conclusion

It seems that Boyer Ahmad district is an endemic area for canine visceral leishmaniasis in Iran.     

Knowledge levels and attitudes of health care professionals toward patients with hepatitis C infection

AIM: To study knowledge levels and attitudes of health care providers toward patients with hepatitis C virus infection in Guilan, a northern province of Iran.METHODS: This cross-sectional study was performed on 239 health care professionals from the Razi Hospital, including doctors, nurses, and operating room technicians. The questionnaires consisted of questions on demographic characteristics, knowledge levels, and attitudes toward hepatitis C patients. The questionnaire was tested in a pilot study and validated by Cronbach’s alpha coefficient. Data were analyzed using SPSS16 software.RESULTS: The mean ± SD knowledge score was 17.43 ± 2.65 (from a total of 22). 51.9% of the participants achieved scores higher than the mean. There was a significant relationship between knowledge score and age (P = 0.001), gender (P = 0.0001), occupational history (P = 0.0001), and educational history (P = 0.027). There was also a significant relationship between attitude level and age (P = 0.002), gender (P = 0.0001), occupational history (P = 0.0001), and educational history (P = 0.035). Physicians were significantly more knowledgeable and showed more positive attitudes. There was a positive correlation between knowledge and attitude scores (P = 0.02).CONCLUSION: Discriminatory attitudes are common among health care providers toward hepatitis C patients. It is therefore necessary to improve their knowledge level and attitude toward this disease.     

The effects of Melissa officinalis (lemon balm) pretreatment on the resistance of the heart to myocardial injury

Context: The antihyperlipidemic, antiarrhythmic, neuroprotective and hepatoprotective effects of Melissa officinalis L. (Lamiaceae) have been reported. However, no study has examined its effects on the resistance of the heart to stressful conditions.

Objective: The objective of this study is to evaluate the effects of aqueous extract of M. officinalis aerial parts on Wistar rat heart with/without cardiac injury.

Materials and methods: Animals were grouped as control, isoproterenol (ISO), M. officinalis without (M50, M100, and M200) and with isoproterenol (M50?+?ISO, M100?+?ISO, and M200?+?ISO). The aqueous extract of M. officinalis was orally administered at dosages of 50, 100, and 200?mg/kg/d, respectively, for 7 consecutive days. On the 6th and 7th day, ISO, M50?+?ISO, M100?+?ISO, and M200?+?ISO groups received 85?mg/kg of isoproterenol for myocardial injury induction. On day 8, hemodynamic parameters were recorded and samplings were done.

Results: The extract (50, 100, and 200?mg/kg) significantly reduced the heart rate (264?±?5, 259?±?5 and 281?±?3 versus 377?±?13 in control group, p?<?0.01). Blood pressure was significantly decreased in M50?+?ISO (75?±?5) versus M50 (110?±?6) and M100?+?ISO (72?±?6) versus M100 (105?±?5?mmHg, p?<?0.01). The malondialdehyde levels of the injured hearts were lower in M50?+?ISO and M100?+?ISO groups than in the ISO group (p?<?0.05). Serum cardiac troponin I was higher in the M200?+?ISO group (5.1?±?1.7) than in the ISO group (2.7?±?0.7?ng/ml, p?<?0.05).

Conclusion: The lower dose of extract, by improving the balance of the redox system and by reducing the heart rate, may increase the heart resistance to injury. However, the higher doses of extract may intensify the injury of ischemic heart.     

Passive opium smoking does not have beneficial effect on plasma lipids and cardiovascular indices in hypercholesterolemic rabbits with ischemic and non-ischemic hearts

Background

To scientifically test a traditionally belief of some Asian countries residents that opium may prevent or have ameliorating effects on cardiovascular diseases (CVD) we investigated the effect of passive opium smoking (POS) on plasma lipids and some cardiovascular parameters in hypercholesterolemic rabbits with ischemic and non-ischemic hearts.

Methods

40 rabbits were fed for 2 weeks with cholesterol-enriched diet and divided to control (CTL), short-term opium (SO) and long-term opium (LO) groups. SO and LO groups were exposed to POS for 3 days and 4 weeks respectively. ECG, blood pressure (BP) and left ventricular pressure recorded and serum lipid and cardiac troponin I levels were measured. Isoproterenol (ISO) injected for induction of cardiac ischemia and after 4 h the above variables were measured along with cardiac histopathology assessment.

Results

HDL cholesterol decreased significantly in LO compared to CTL group (35 ± 5 vs 53 ± 5 mg/dl). Groups treated with ISO showed significantly higher increments in troponin I level (P < 0.05) except for LO group and reduction of BP was higher in ISO and SO + ISO groups compared to CTL and SO groups respectively (−38 ± 6 vs −23 ± 4 and −37 ± 11 vs −11 ± 3 percent respectively, P < 0.05). Reduction in BP was significantly lower in LO + ISO compared to ISO group. Opium exposure caused a trend of increase in blood pressure, LDL cholesterol and ECG disturbances, attenuated ISO induced myonecrosis but augmented tissue congestion and hemorrhage.

Conclusion

POS can be considered as a CVD risk factor. Opium does not reduce BP or cholesterol level, as is anticipated by its users.     

Cardiovascular effect of nifedipine in morphine dependent rats: hemodynamic, histopathological, and biochemical evidence

Aim. To investigate whether administration of nifedipine has considerable therapeutic effect in morphine-dependent rats. Methods. Sixty animals were randomized into control, morphine, morphine plus nifedipine, and morphine plus dimethyl sulfoxide (DMSO, as nifedipine soluble) groups. Each group consisted of two subgroups, with and without heart injury. The groups were treated with incremental doses of morphine or morphine plus nifedipine daily for 7 days. Myocardial injury was induced by isoproterenol (50 mg/kg i.p.) on the day 7. On the day 8, the heart rate (HR), blood pressure (BP), rate-pressure product (RPP), and the plasma level of cardiac troponin I were measured and the hearts were histopathologically examined. Results. In morphine-dependent rats, nifedipine administration was associated with a significantly higher decrease in the plasma level of cardiac troponin I than the administration of morphine alone. This finding was also significant in dependent animals that received only DMSO. HR, BP, RPP, and histopathological indices did not show significant changes in the presence of nifedipine. Conclusion. Administration of nifedipine failed to show a significant therapeutic effect in morphine-dependent rats, especially in the group with myocardial injury.     

The efficacy of sour tea (Hibiscus sabdariffa L.) on selected cardiovascular disease risk factors: A systematic review and meta‐analysis of randomized clinical trials

This study sought to summarize clinical evidence of sour tea (Hibiscus sabdariffa L.) administration on cardiovascular disease risk factors. PubMed, Scopus, Institute for Scientific Information Web of Science, and Google Scholar were systematically searched from inception to June 2019 to identify randomized clinical trials, which assessed the effect of sour tea consumption on lipid profiles, fasting plasma glucose, and blood pressure in adult populations. Mean and standard deviation for each parameter were extracted to calculate effect size. Cochrane Collaboration tools were used to evaluate risk of bias assessment. A total of seven randomized clinical trials consisting 362 participants were included in the meta‐analysis. Pooled effect size demonstrated that sour tea consumption significantly reduces fasting plasma glucose (?3.67 mg/dl, 95% confidence interval, CI [?7.07, ?0.27]; I² = 37%), systolic blood pressure (?4.71 mmHg, 95% CI [?7.87, ?1.55]; I² = 53%), and diastolic blood pressure (?4.08 mmHg, 95% CI [?6.48, ?1.67]; I² = 14%). Although no significant effect was observed on triacylglycerol, total cholesterol, and high‐density lipoprotein cholesterol following sour tea consumption, a trend toward a significant reduction was found in low‐density lipoprotein cholesterol serum concentrations (p = 0.08). This systematic review and meta‐analysis suggests that sour tea consumption could have beneficial effect in controlling glycemic status and blood pressure among adult population.     

Efficacy of Melissa officinalis in Suppressing Ventricular Arrhythmias following Ischemia-Reperfusion of the Heart: A Comparison with Amiodarone

Objective

We aimed to assess the influence of Melissa officinalis (lemon balm), a well-known herbal drug with numerous applications in traditional and modern medicine, on cardiac conduction and susceptibility to lethal ventricular arrhythmia.

Materials and Methods

Forty-two male Wistar rats were divided into a control group (CTL), an M. officinalis group that received the aqueous extract of M. officinalis L. intraperitoneally (i.p.) at dosages of 50, 100, 200 and 400 mg/ml/kg, respectively, and an amiodarone group (Amio group) that received 30 mg/ml/kg i.p. of amiodarone. Heart ischemia/reperfusion was induced by the ligation and release of the left anterior descending branch of the left coronary artery.

Results

There were no statistical differences between the groups in the basal heart rate and blood pressure. PR, corrected QT (QTc) and QRS intervals increased in the M. officinalis and Amio groups. PR and QTc were statistically significant only in the Amio group and QRS was significant only in the group receiving 400 mg of M. officinalis (M400 group) in comparison with the CTL group. During the reperfusion period, the decrease in ventricular fibrillations was statistically significant in all groups (except the M400 group) when compared with the CTL group. The score of arrhythmia severity also decreased, but was statistically significant only in the Amio group (p < 0.05 vs. CTL group).

Conclusions

Our findings suggest that M. officinalis extract has a mild protective effect against reperfusion-induced lethal ventricular arrhythmias in rats.Key Words: Melissa officinalis (lemon balm), Heart, Ischemia-reperfusion, Ventricular arrhythmias     

Potential Mechanisms Involved in the Anticonvulsant Effect of Walnut Extract on Pentylenetetrazole-Induced Seizure

Objective

It was the aim of this study to determine the potential effect of walnut kernel extract (WKE) on experimentally induced seizures in rats and to evaluate the role of benzodiazepines and ethosuximide (ESM) within these pathways.

Materials and Methods

Male Wistar rats were selected and divided into eight groups. Seizures were evoked by intravenous infusion of pentylenetetrazole (PTZ; 2 mg/ml/min). In combination with PTZ, animals were treated with vehicle or WKE (100 mg/kg i.p.), with or without cotreatment with either flumazenil (FMZ; 5 mg/kg i.p.), ESM (150 mg/kg i.p.) or diazepam (DPZ; 0.5 mg/kg i.p.).

Results

WKE administration significantly increased the PTZ dose needed to induce the first myoclonic jerk (13.09 ± 1.29 vs. 49.71 ± 12.03 mg/kg; p < 0.001), decreased the severity of seizure grades and reduced the mortality rate to 0%. FMZ did not significantly reduce the anticonvulsant effect of WKE. The combination of DPZ and WKE showed a synergic anticonvulsant effect, whereas ESM had no significant influence (p > 0.05) on the WKE effects.

Conclusion

These findings indicated that WKE was effective at reducing seizure severity, at increasing the dose to the first myoclonic jerk and highly efficacious at preventing mortality, because 100% of animals were protected. It seems that this positive effect could apply through signaling pathways other than benzodiazepine-mediated γ-aminobutyric acid receptors and may at least in part be similar to ESM.Key Words: Walnut kernel, Seizure, Rat, Anticonvulsant effect, Pentylenetetrazole