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

Exercise Training Attenuates Cardiac Vulnerability and Promotes Cardiac Resistance to Isoproterenol-Induced Injury Following Hookah Smoke Inhalation in Male Rats: Role of Klotho and Sirtuins

Hookah smoking is on the rise around the world. Present study investigated the heart resistance to harmful stress following long-term waterpipe tobacco smoking (WTS) and moderate-intensity exercise training intervention in male Wistar rats. Animals were randomly divided into a non-ischemic heart control group and four ischemic heart groups including ISO (isoproterenol-treated), Ex + ISO (subjected to exercise plus ISO), S + ISO (exposed to hookah smoke plus ISO), and Ex + S + ISO (subjected to exercise along with hookah smoke plus ISO). After eight weeks of training and WTS, heart ischemia induced by isoproterenol injections. Then, cardiac functional indices and some biochemical and histopathological parameters were assessed. WTS + ISO reduced systolic pressure, ± dP/dt max, and contractility indices (P < 0.001 vs. ISO group) and increased end diastolic pressure and Tau index (P < 0.001 vs. ISO) of the left ventricle. Also, WTS + ISO was associated with an increase in Bax protein level and Bax/Bcl-2 ratio (P < 0.05 and P < 001, respectively, vs. ISO group) as apoptotic markers of heart tissue. Hookah smoke significantly decreased SIRT1 (P < 0.05 and P < 0.001, respectively, vs. ISO) and klotho (P < 0.01 and P < 0.001, respectively, vs. ISO) in serum and heart, and SIRT3 and pS9-GSK-3β (P < 001 and P < 0.05, respectively, vs. ISO) in heart tissue. Combination of exercise with WTS prevented the hookah smoke-induced alterations in apoptotic markers, cardiac functional indices, and SIRT1, SIRT3, klotho, and pS9-GSK-3β proteins. The findings demonstrated that hookah smoke inhalation intensifies ventricular dysfunction and decreases heart resistance to harmful stresses. Moderate-intensity exercise training attenuated these complications partly through recovering the klotho and sirtuins levels and apoptosis-survival balancing.

Mechanobiology Assays with Applications in Cardiomyocyte Biology and Cardiotoxicity

Cardiomyocytes are the motor units that drive the contraction and relaxation of the heart. Traditionally, testing of drugs for cardiotoxic effects has relied on primary cardiomyocytes from animal models and focused on short-term, electrophysiological, and arrhythmogenic effects. However, primary cardiomyocytes present challenges arising from their limited viability in culture, and tissue from animal models suffers from a mismatch in their physiology to that of human heart muscle. Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) can address these challenges. They also offer the potential to study not only electrophysiological effects but also changes in cardiomyocyte contractile and mechanical function in response to cardiotoxic drugs. With growing recognition of the long-term cardiotoxic effects of some drugs on subcellular structure and function, there is increasing interest in using hiPSC-CMs for in vitro cardiotoxicity studies. This review provides a brief overview of techniques that can be used to quantify changes in the active force that cardiomyocytes generate and variations in their inherent stiffness in response to cardiotoxic drugs. It concludes by discussing the application of these tools in understanding how cardiotoxic drugs directly impact the mechanobiology of cardiomyocytes and how cardiomyocytes sense and respond to mechanical load at the cellular level.

Limb Blood Flow Restriction Plus Mild Aerobic Exercise Training Protects the Heart Against Isoproterenol-Induced Cardiac Injury in Old Rats: Role of GSK-3β

The present study was conducted to evaluate the effect of blood flow restriction (BFR) training on cardiac resistance to isoproterenol (ISO) induced heart injury in old rats and examined the hypothesis that BFR training may interfere with age-associated impairment of mitochondria by the inhibitory phosphorylation of GSK-3β at Ser9. Old male Wistar rats were divided into the following six groups: CTL (control), ISO (isoproterenol-treated), Sh + ISO (sham-operated plus ISO), BFR + ISO (blood flow restriction plus ISO), Sh-Ex + ISO (sham-operated subjected to exercise and ISO), and BFR-Ex + ISO (blood flow restriction along with exercise and ISO). 10 weeks of exercise training was considered. Then, cardiac injury was induced and physiological, histological, and biochemical parameters were recorded and assessed. Compared to CTL group, isoproterenol administration significantly reduced the systolic arterial pressure (SAP), left-ventricular systolic pressure (LVSP), and ± dp/dt max (P < 0.05). BFR training improved these parameters in the way that BFR-Ex + ISO group had higher SAP, LVSP and ± dp/dt max (P < 0.05) and lower LVEDP (left-ventricular end diastolic pressure) (P < 0.01) than untrained and Sh-Ex + ISO groups. The pS9-GSK-3β and pS9-GSK-3β/GSK-3β ratio were increased in the BFR-Ex + ISO group compared to CTL, ISO, Sh + ISO, and BFR + ISO groups (P < 0.05). The level of plasma cardiac Troponin-I and the severity of the injuries were significantly reduced in BFR-Ex + ISO group versus other cardiac damaged groups. In conclusion, our findings clearly confirmed the cardio-protective effect of BFR training against ISO-induced myocardial injury. Increased phosphorylated GSK-3β and angiogenesis in this model of exercise justify the resistance of old hearts facing stressful situations.

Opioids and Cardiac Arrhythmia: A Literature Review

OBJECTIVE

One of the most important side effects of opioids is their influence on the electrical activity of the heart. This review focusses on the effects of opioids on QT interval prolongation and their arrhythmogenic liability.

METHODS

By using various keywords, papers published up to 2018 in different databases were searched and identified. The search terms were opioids names, corrected QT interval, human-ether-a-go-go gene, torsades de pointes (TdP), cardiac arrhythmias, opioid dependence and other relevant terms. It emphasized the effects of each opioid agent alone on electrocardiogram (ECG) and some interactions.

RESULTS

Available data indicate that some opioids such as methadone are high-risk even at low doses, and have potential for prolongation of the QT interval and development of TdP, a dangerous ventricular tachycardia. A number of opioids such as tramadol and oxycodone are intermediate risk drugs and may develop long QT interval and TdP in high doses. Some other opioids such as morphine and buprenorphine are low-risk drugs and do not produce QT interval prolongation and TdP at least in routine doses. Opium-consumers are at higher risk of supra-ventricular arrhythmias, sinus bradycardia, cardiac block and atrial fibrillation.

CONCLUSION

The cardiac arrhythmogenicity of various opioids is different. Methadone has a higher capability to induce long QT interval and dangerous arrhythmias in conventional doses than others. To reduce of arrhythmogenic risk, high doses of opioids must be used cautiously with periodic monitoring of ECG in high-risk consumers such as patients under opioid maintenance treatment.

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.

Endogenous opiates and behavior: 2013

This paper is the thirty-sixth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2013 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.