Physiology and Pharmacology
Volume:16 Issue: 4, 2013

Temperament (Mizaj), as an individual factor, has great importance in traditional medicine and its use in diagnosis and treatment of diseases, as well as the individual lifestyle is very common. Since medicine moves toward Personalized Medicine, the root of individual differences will find its position in different aspects of medicine in early future. In traditional medicine, temperament is defined as the only cause of individual differences and this scientific principle in the near future will be highly regarded. Recent studies also indicate the important role of temperament in body functions. Association of temperament with autonomic and immune systems, blood groups and various diseases also confirms this role. The present study provides a scheme of the history of temperament science, current status and its future, and tries to map a correct portray of temperament trend from the past to the future.

Isolated perfused heart models such as perfusion and superfusion are commonly used for mammalian heart research. However, there are several fundamental limitations in the current techniques. In perfusion model, a suitable cannula is connected to the aorta and the perfusion is retrogradely performed. But, electrode displacement is a potential unwanted event resulted from heart contractions. In superfusion model, atrioventricular node (AV) node area is completely visible and fixed in the tissue bath after appropriate preparation, but tissue ischemia is inevitable due to the absence of cell to cell nutrition. The aim of the present study was to create a novel isolated dual perfusion/superfusion model to be used in heart physiological and pharmacological studies. The rabbit hearts (n=10) were excised. After preparation of proper sections, the electrodes were attached till the steady state appeared. The stimulation protocols consisting Wenckebach and recovery were then carried out during the isolated dual perfusion/superfusion as well as perfusion and superfusion models. The AV node conduction time was increased from 33±4 ms in the isolated dual perfusion/superfusion heart model to 43±5 and 52±5 ms in perfusion and superfusion models, respectively (P<0.05). In addition, Wenckebach cycle length, effective and functional refractory periods were increased in perfusion and superfusion models compared to the isolated dual perfusion/superfusion model (P<0.05). This study shows the superiority of the isolated dual perfusion/superfusion heart model in tissue nutrition compared to the other common methods of mammalian heart studies.

Several reports show a relationship between health equity, and health status and longevity of individuals. In this study, effects of food deprivation, inequality and social instability were investigated on the formation of lipofuscin pigment in Balb/C mice by histopathological and biochemical methods. Thirty-six male mice were divided into 6 groups, then different kinds of stress (food deprivation, inequality and cage-mate change) were implemented on these groups for 2 weeks according to the protocol. Lipofuscin was biochemically measured in the brain homogenate of one hemisphere by Shen’s method. The other brain hemisphere was used to qualitatively investigate the accumulation of lipofuscin by fluorescent microscope and it was also stained with periodic acid Schiff and examined with light microscope. Food deprivation alone did not cause significant differences in the amount of lipofuscin, but in food deprived and inequality experienced animals the amounts of lipofuscin was well above controls (P<0.05); moreover, in the mice, which merely experienced unstable social status, the increase of lipofuscin was significant compared to the controls (P<0.001). When all of three social stresses were applied simultaneously, lipofuscin changes were more obvious. The microscopic examination of tissue samples showed accumulation of lipofuscin in test conditions. Food deprivation, injustice and unstable social status, especially when are applied simultaneously, can increase brain lipofuscin levels. Considering the role of this pigment in aging, the probability of appearance of early aging can be considered after exposure to social stress.

Recently, it has been demonstrated that olive leaf extract and its main component have calcium channel blocker, anti-inflammatory and anti-oxidative properties. However, the effects of olive leaf extract on opioid dependence have not yet been clarified. To develop morphine dependence, morphine was injected twice daily for 7 days according to an escalating dose in rats. On day 7, the animals received naloxone (3 mg/kg, i.p.) 5 h after the last injection of morphine. Withdrawal signs (weight loss, abdominal contraction, diarrhea, teeth chattering, jumping, grooming and ptosis) were evaluated during 1h after naloxone. To determine the effect of OLE and oleuropein on the development of morphine dependence, OLE was given at doses of 200, 300 and 500 mg/kg and oleuropin with 10 mg/kg (i.p.) concomitant with morphine. Our results showed that rats chronically injected with morphine showed physical dependence. OLE (300 mg/kg) and oleuropin (10 mg/kg) could attenuate naloxone-induced withdrawal syndrome. Our data revealed that olive leaf extract had a beneficial effect on chronic morphine-induced side effects such as physical dependence and can be useful in the period of drug withdrawal and its main component, oleuropein, is responsible for such observed effects.

Chronic heterogeneous stress may be better for evaluation of the effect of chronic stress situations on the nociceptive behaviour. The present study investigated the effects of chronic heterogeneous sequential stress on thermal-induced nociception and formalin induced pain behavior in rats. In the present study, adult rats (220-300 g) were used. Animals were divided in stressed and non-stressed groups. Heterogeneous sequential stress including food deprivation, water deprivation, restraint, restraint at room temperature, restraint at 4 ͦ C, forced swimming and social isolation stress. Formalin and hot-plate tests were used as chemical and thermal pain model effects in rats, respectively. While non-stressed animals gained weight during the experiments, stressed rats lost their weight. Chronic heterogeneous sequential stress significantly increased latency to hot-plate test when compared to control, while it increased the nociceptive behaviour in phase 2 of formalin test in male rats compared to control ones. The model of chronic heterogeneous sequential stress presented here may be useful in evaluating the basic mechanisms linking stress and pain and suggest a method to assess the potential therapeutic efficacy of drugs targeting painful disorders with a strong stress component.

The current investigations on Health Equity, primarily point to the harmful health consequences of being in a stressful social hierarchy. The repetitive nature of social conflicts seems to favor the induction of hyperalgesia or hypoalgesia both in rodents and humans, and it can also affect the immune system. In this study, the effects of changes in social status on pain perception as well as alterations of pro-inflammatory cytokines were investigated in Balb/C mice. By implementation of a sensory contact model in 22 male inbred mice (stress group) from 30 mice of the Balb/c strain and modeling of dominance/submissive relationship, each mouse was injected by 20 μl of formalin 2% and their pain behavior was scored, then serum concentrations of proinflammatory cytokines were measured in all mice. Our results showed that subordinate mice in chronic phase of formalin test were hypoalgesic as compared to the control and dominant mice (P<0.05). On the other hand, dominant mice were hypoalgesic as regards to subordinate mice during acute phase of formalin test. IL-1 and IL-6 concentrations in serum of dominant and subordinate mice were well above the control group. These results revealed that despite similar increase of proinflammatory cytokine's level in dominant and subordinate subjects; social status can differently affect pain perception.

Occurrence of cardiac arrhythmias and myocardial infarction are two main deleterious events that are caused by ischemia-reperfusion (IR) injury in the heart. Cardiac preconditioning represents the most potent method of rescuing heart tissue from undergoing irreversible ischemic damage. The aim of the present study was to evaluate oxytocin (OT) cardioprotective effects and its signaling pathways in cardiac arrhythmias including ventricular tachycardia (VT) and ventricular fibrillation (VF) in anesthetized rats. Fifty-four rats were divided into nine groups. Animals’ hearts were subjected to 25 min ischemia and 2 h reperfusion. Oxytocin was used 25 min prior to ischemia. In certain groups, atosiban (an oxytocin receptor antagonist), atractyloside (an opener of mitochondrial permeability transition pore, mPTP) and N-acetylcysteine (a reactive oxygen species scavenger) were used 10 min prior to OT administration. Then, the severity and incidence of cardiac arrhythmias including VT and VF were measured. OT administration significantly decreased the severity and incidence of cardiac arrhythmias compared to the IR group (P<0.05). Administration of atosiban, atractyloside and N-acetylcysteine abolished the cardiac preconditioning effect of OT in cardiac arrhythmia (P<0.05). The present study demonstrates that preconditioning with oxytocin reduced ischemia-reperfusioninduced ventricular arrhythmias and its signaling pathways are probably mediated through mitochondrial permeability transition pore and reactive oxygen species.

Mobile phones create high-frequency electromagnetic fields around them when in use. The close proximity of mobile phones to the user’s head leads to the absorption of part of the electromagnetic waves into the head and the brain. We have elucidated the alteration in cognitive function of the male and female offspring rats, which were exposed to chronic mobile phone exposure during their gestational period using Shuttle box and Morris Water Maze (~20 days). The results of the passive avoidance and Morris Water Maze assessment of learning and memory performance showed a decrease in learning and memory in rats exposed to mobile phone. Exposure to EMF increased the shock number (Shuttle box test) and distance (Morris Water Maze test) compared to control groups (P<0.05). When the testing was performed 1 and 7 days after the shock experience (28-30 days post- mobile phone exposure), the step-through latency was significantly decreased in male and female mobile phone-exposed rats compared to the control rats (P<0.01). Results from the probe test were measured as mean percentage [%] time spent in correct quadrant showed that mobile phone exposure significantly decreased the percent time spent in the correct quadrant compared to control (p<0.05). Our results suggest that, mobile phone is able to induce a serious disruption in learning and memory and these observed deficits would suggest that we should limit the usage of these instruments during pregnancy.

The use of zinc supplements can decrease somatic and visceral pains. Exercise also increases the pain tolerance. In recent years, production and use of nano metal particles such as nano ZnO for pharmaceutical, hygienic and industrial purposes is rapidly increasing, while studies about its effects on human health are limited. The aim of the present study was to compare the effect of chronic administration of nano and conventional ZnO on nociception in the presence and absence of anti nociception mechanisms induced by aerobic exercise. In this investigation, adult male Wistar rats (185±10 gr) were used in the following groups: Control (receiving saline, without exercise), exercise, conventional ZnO and/or nano ZnO daily (1 mg/kg i.p., 5 days a week) for 6 weeks with and without aerobic exercise. Exercise groups did daily protocol of exercise for 30 minutes after drug injection. In the end, analgesia time was evaluated by hot plate test. Exercise, ZnO and nano ZnO significantly reduced pain (P<0.01, P<0.05, P<0.01). Nano ZnO showed a better analgesic effect in comparison to conventional ZnO, but this difference was not significant. Similarly, no significant difference was found between the group that had only exercise and groups treated with ZnO and/or nano ZnO. Antinociception mechanism induced by exercise is not potentiated with nano and conventional ZnO.

Recently, the search for appropriate hypoglycemic agents has been focused on plants. Teucrium polium is traditionally used in Iran to manage, control and treat diabetes. We designed this study to elucidate the effect of the administration of oral doses of aqueous and ethanol extract from Teucrium polium on plasma glucose, lipid profiles and liver enzymes in diabetic and non diabetic rats. In this study, we used 50 rats, which were divided into 5 groups (n=10): two groups served as nondiabetic controls (NDC), while the other groups had diabetes induced with a single injection of streptozotocin (STZ). Teucrium polium-treated chronic diabetic (TE-CD) and Teucrium polium-treated controls (TE-C) received 1g/l of Teucrium polium added to their drinking water for 8 weeks. Administration of Teucrium polium caused Ca/Mg ratio, plasma glucose, glucose tolerance test (IPGTT), high density lipoprotein (HDL), triglyceride, very low density lipoprotein (VLDL) concentrations to return to normal levels, but total cholesterol and low density lipoprotein (LDL) and liver enzyme were increased. Our results support the hypothesis that Teucrium polium could play a role in the management of diabetes, but it has toxic effects on the liver in STZ-induced diabetic rats. It seems that Teucrium polium cannot be used for prevention of type one diabetes.

Neuropathic pain is a chronic pain that occurs as an injury to neuronal cells and abnormality in nervous and immune systems function. Also diabetic neuropathy diseases accompany with variety of pain syndromes such as allodynia and hyperalgesia. Thus, the aim of the present study was to investigate the chronic effects of incremental activity in the form of endurance training on neuropathic pain in Streptozotocin-induced diabetic rats. Twenty eight adult male Wistar rats in the weight range of 326.3±8.4 gr, randomly assigned to four groups: diabetes and training, diabetes and not training, healthy and training and healthy and not training. -For inducing neuropathic pain, after twelve hours of food deprivation, intraperitoneal injection of STZ solution (45 mg/Kg) method was used. Two weeks after STZ injection, pain behaviors were measured with mechanical allodynia and thermal hyperalgesia tests. Then, the moderate intensity endurance training protocol was performed for six weeks and seventy two hours after the last training session, pain behavior tests were performed again. Incremental activity in the form of moderate intensity endurance training led to significant improvement of mechanical allodynia and thermal hyperalgesia in rats. Also, in compare with diabetic control, training led to significant decrease in blood glucose levels in diabetic training group. Incremental activity in the form of moderate intensity endurance training could have chronic effects on neuropathic pain improvement. So, it is suggested that moderate intensity endurance training could be used as a non-pharmacotherapy intervention in the field of neuropathic pain for suffering patients.