Effects of cannabidiol on contractions and calcium signaling in rat ventricular myocytes

© 2015 Elsevier Ltd. Cannabidiol (CBD), a major nonpsychotropic cannabinoid found in Cannabis plant, has been shown to influence cardiovascular functions under various physiological and pathological conditions. In the present study, the effects of CBD on contractility and electrophysiological properties of rat ventricular myocytes were investigated. Video edge detection was used to measure myocyte shortening. Intracellular Ca2+ was measured in cells loaded with the Ca2+ sensitive fluorescent indicator fura-2 AM. Whole-cell patch clamp was used to measure action potential and Ca2+ currents. Radioligand binding was employed to study pharmacological characteristics of CBD binding. CBD (1μM) caused a significant decrease in the amplitudes of electrically evoked myocyte shortening and Ca2+ transients. However, the amplitudes of caffeine-evoked Ca2+ transients and the rate of recovery of electrically evoked Ca2+ transients following caffeine application were not altered. CBD (1μM) significantly decreased the duration of APs. Further studies on L-type Ca2+ channels indicated that CBD inhibits these channels with IC50 of 0.1μM in a voltage-independent manner. Radioligand studies indicated that the specific binding of [3H]Isradipine, was not altered significantly by CBD. The results suggest that CBD depresses myocyte contractility by suppressing L-type Ca2+ channels at a site different than dihydropyridine binding site and inhibits excitation-contraction coupling in cardiomyocytes

Effects of Endogenous Cannabinoid Anandamide on Voltage-Dependent Sodium and Calcium Channels in Rat Ventricular Myocytes

BACKGROUND AND PURPOSE: The endocannabinoid anandamide (N-arachidonoyl ethanolamide; AEA) exerts negative inotropic and antiarrhythmic effects in ventricular myocytes. EXPERIMENTAL APPROACH: Whole-cell patch-clamp technique and radioligand-binding methods were used to analyse the effects of anandamide in rat ventricular myocytes. KEY RESULTS: In the presence of 1-10 μM AEA, suppression of both Na(+) and L-type Ca(2+) channels was observed. Inhibition of Na(+) channels was voltage and Pertussis toxin (PTX) - independent. Radioligand-binding studies indicated that specific binding of [(3) H] batrachotoxin (BTX) to ventricular muscle membranes was also inhibited significantly by 10 μM metAEA, a non-metabolized AEA analogue, with a marked decrease in Bmax values but no change in Kd . Further studies on L-type Ca(2+) channels indicated that AEA potently inhibited these channels (IC50 0.1 μM) in a voltage- and PTX-independent manner. AEA inhibited maximal amplitudes without affecting the kinetics of Ba(2+) currents. MetAEA also inhibited Na(+) and L-type Ca(2+) currents. Radioligand studies indicated that specific binding of [(3) H]isradipine, was inhibited significantly by metAEA. (10 μM), changing Bmax but not Kd . CONCLUSION AND IMPLICATIONS: Results indicate that AEA inhibited the function of voltage-dependent Na(+) and L-type Ca(2+) channels in rat ventricular myocytes, independent of CB1 and CB2 receptor activation

FPGA-based reliable TMR controller design for S2A architectures

[abstract not available

Monitoring electromagnetic pollution using wireless sensor networks

[abstract not available

General expressions for downlink signal to interference and noise ratio in homogeneous and heterogeneous LTE-Advanced networks

The interference is the most important problem in LTE or LTE-Advanced networks. In this paper, the interference was investigated in terms of the downlink signal to interference and noise ratio (SINR). In order to compare the different frequency reuse methods that were developed to enhance the SINR, it would be helpful to have a generalized expression to study the performance of the different methods. Therefore, this paper introduces general expressions for the SINR in homogeneous and in heterogeneous networks. In homogeneous networks, the expression was applied for the most common types of frequency reuse techniques: soft frequency reuse (SFR) and fractional frequency reuse (FFR). The expression was examined by comparing it with previously developed ones in the literature and the comparison showed that the expression is valid for any type of frequency reuse scheme and any network topology. Furthermore, the expression was extended to include the heterogeneous network; the expression includes the problem of co-tier and cross-tier interference in heterogeneous networks (HetNet) and it was examined by the same method of the homogeneous one

Effect of religious beliefs on the smoking behaviour of university students: quantitative findings from Malaysia

The Malaysian official Islamic authorities have issued a ‘‘fatwa’’ (Islamic ruling) regarding smoking practice which prohibits Muslims from smoking because of its potential harm to health. Since the prevalence of smoking among Malaysian students is high, this study was designed to explore the perceptions and opinions of Malaysian Muslim students towards smoking in International Islamic University of Malaysia. A prospective, cross-sectional study was conducted among School of Science students in International Islamic University Malaysia. Convenience sampling approach was used to recruit 323 students based on sample size calculation. A content- and face-validated questionnaire was used to collect the data from the participants. Non-smokers highly supported the fatwa on smoking forbiddance than smokers (94 vs 64.3 %, p = 0.001). A significant proportion of non-smokers believed that Islam prohibits smoking because of its potential harm (94.9 vs 71.4 %, p = 0.001). Majority of smokers agreed that addiction is the main barrier towards smoking cessation (78.6 vs 61.5 %, p = 0.019). The results showed positive influences of Islamic beliefs on the non-smokers. Further studies are required to validate these findings by surveying other universities of Malaysia

New hybrid frequency reuse method for packet loss minimization in LTE network

This paper investigates the problem of inter-cell interference (ICI) in Long Term Evolution (LTE) mobile systems, which is one of the main problems that causes loss of packets between the base station and the mobile station. Recently, different frequency reuse methods, such as soft and fractional frequency reuse, have been introduced in order to mitigate this type of interference. In this paper, minimizing the packet loss between the base station and the mobile station is the main concern. Soft Frequency Reuse (SFR), which is the most popular frequency reuse method, is examined and the amount of packet loss is measured. In order to reduce packet loss, a new hybrid frequency reuse method is implemented. In this method, each cell occupies the same bandwidth of the SFR, but the total system bandwidth is greater than in SFR. This will provide the new method with a lot of new sub-carriers from the neighboring cells to reduce the ICI which represents a big problem in many applications and causes a lot of packets loss. It is found that the new hybrid frequency reuse method has noticeable improvement in the amount of packet loss compared to SFR method in the different frequency bands. Traffic congestion management in Intelligent Transportation system (ITS) is one of the important applications that is affected by the packet loss due to the large amount of traffic that is exchanged between the base station and the mobile node. Therefore, it is used as a studied application for the proposed frequency reuse method and the improvement in the amount of packet loss reached 49.4% in some frequency bands using the new hybrid frequency reuse method

Lifetime Enhancement Techniques for MANET Routing in Space Exploration Applications

[abstract not available

Disparity and compatibility, familiarity and perception among waterpipe tobacco smokers (shisha) in Malaysia: a comparative study

Background: In Malaysia, although the number of Shisha smokers has not exceeded the regular cigarette users, waterpipe smoking (Shisha) has been appeared as a new form of tobacco use, especially among the new generation. This study aims to describe the comparative characteristics, familiarities, and motives for Shisha use in some states of Malaysia. Methods: A cross-sectional survey using a new validated self-administered, bilingual questionnaire was conducted among Shisha smokers in Pulau Penang and Kuantan Malaysian cities. Five hundred questionnaires were distributed evenly and randomly in Shisha lounges around the mentioned two cities. Results: A total of 297 people (55.8%) agreed to participate in the study. The majority of the study participants were male (82.1%), Malay (82.8 %), and currently studying or graduated from university or college (67.5 %). Almost half (49.3%) of the study participants were Shisha users. The majority (80.3%) of respondents had smoked Shisha at least once in the last six months More than half of the respondents (58%) were influenced by comrades in the first trial of Shisha smoking. The catchy smell, the flavor, and taste of Shisha, and curiosity were the main attractive factors for smoking Shisha among study participants (30%, 29%, & 12%, respectively). However, the major contributory factors to continue smoking Shisha were pleasure and happiness, relief from tension, stress, and boredom, and passing of time (61.3%, 56.6%, & 47.4%, respectively). Study results showed that respondents' residency was a differential significant factor in attitudes, perceptions, and motivation toward experimentation and continuation of Shisha smoking. The vast majority of Penangites perceived that Shisha was purified from harmful substances, Shisha smoking did not irritate the bronchi, and there was no association between Shisha smoking and lung cancer (82.5%, 64.6%, & 62.1%, respectively). About half of the respondents believed that Shisha was less harmful, less addictive, and contained less nicotine than a cigarette (44.1%, 68.9%, & 67.5, respectively). There is a strong belief among the study population (67.5%) that the popularity of Shisha will increase over the next half-decade. Conclusion: High prevalence of Shisha smoking associated with the considerable poor level of knowledge about Shisha use has been noticed among the study population. The results indicated the role played by peers in instigating the testing or using shisha. Study findings affirm the necessity for further research into contributory factors influencing Shisha use