Coronary angiogenesis during morphine and nicotine withdrawal in two-kidney one clip hypertensive (2K1C) rats.

OBJECTIVE: This study was aimed to investigate the effects of addiction to nicotine and morphine and their withdrawal on coronary angiogenesis and serum NO concentrations in two-kidney one-clip hypertensive (2K1C) rats. METHODS: Male hypertensive rats were divided into the two below groups: Group (1): Rats received saline for 8 weeks (N=8); Group (2): Rats received morphine and nicotine for 8 weeks (n=32). At the end of 8 weeks, the groups (2) were divided into the four sub-groups, which three of them were treated with withdrawal drugs. Following treatments, blood pressure, heart rate, plasma renin activity (PRA), NO concentration and capillary density were measured. RESULTS: Results showed that blood pressure was significantly reduced in the addicted group when compared to non-addicted (p<0.05). The withdrawal completely reversed blood pressure to the level observed pre-addiction (p<0.05). Coronary angiogenesis was significantly lower in the addicted group in comparistion to normal (p<0.05) but withdrawal of addiction did not improve angiogenesis. CONCLUSION: On the basis of the present findings, it may be indicative that the risk of cardiovascular complications in addiction is concurrent to chronic hypertension, which shows the importance of early diagnosis and treatment in clinical condition (Fig. 4, Ref. 59).

Morphine and nicotine addiction and withdrawal influence baroreflex sensitivity and blood pressure in two-kidney one clip hypertensive (2K1C) rats.

OBJECTIVE: This study aimed to investigate the effects of addiction to morphine and nicotine as well as their withdrawal on both baroreflex sensitivity and blood pressure in hypertensive rats. METHODS: In this experimental study 40 male rats were divided into two main groups as follows: in group I, hypertensive rats received saline for 8 weeks; in group II, hypertensive rats were treated with morphine and nicotine for 8 weeks. At the end of 8 weeks group II rats were divided into four sub-groups including, 3 sub-groups of those were put on drug withdrawal protocol. At the end of experiment, blood pressure, heart rate, plasma renin activity (PRA), serum NO concentration and baroreflex sensitivity (BRS) were measured. RESULTS: RESULTS demonstrated that BP and BRS were significantly lower in addicted to morphine and nicotine hypertensive rats compared to control (p < 0.05). Addiction withdrawal (in morphine and nicotine withdrawal rats) completely reversed BP and BRS to the pre-addiction levels (p < 0.05). Withdrawal in the only nicotine treated group lowered BP and BRS compared to group that had received morphine and nicotine together (p < 0.05). CONCLUSION: RESULTS of current study may propose simultaneous morphine and nicotine withdrawal can prevent cardiovascular complications raised due to withdrawal (Fig. 5, Ref. 58).

Comparing the long-term retention of a physiology course for medical students with the traditional and problem-based learning.

The rapid improvements in medical sciences and the ever-increasing related data, however, require novel methods of instruction. One such method, which has been given less than due attention in Iran, is problem-based learning (PBL). In this study, we aimed to evaluate the impact of study skills and the PBL methods on short and long-term retention of information provided for medical students in the course of respiratory physiology and compare it with traditional learning method. In this study, 39 medical students from Medical School of Kerman University of Medical Sciences, Kerman, Iran (2006-2010) were enrolled in the study and allocated randomly in three equal groups (13 in each group). All groups underwent a pre-test to be assessed for their basic information regarding respiratory physiology. Two groups were instructed using the traditional method, and one group used PBL. Among the two groups of the traditional method, one was instructed about study skills and the other was not. Once the PBL group took the study skill workshop, they were aided by tutors for their education. In the final term test, those students who had learned study skills and were instructed with the traditional method scored higher compared to other groups (p < 0.05). However, in the 1 year (p < 0.05) and 4 year (p < 0.01) interval examinations, the PBL group achieved significantly higher scores. Despite the fact that PBL had no positive effect on the final term exam of our students, it yielded a more profound and retained understanding of the subject course. Moreover, considering the positive effect of study skills on long-term student scores, we recommend students to receive instructions regarding the appropriate study skills when initiated into universities.

The effect of maintenance and reversal of DOCA-Salt hypertension on extravasation of macromolecules and serum nitric oxide concentration in male rats.

OBJECTIVE: Previous studies indicated that there are some functional and morphological changes of endothelial cells in hypertension. The aim of this study was to investigate the effect of DOCA-Salt hypertension and its reversal on extravasation of macromolecules (endothelial permeability) and serum Nitric Oxide (NO) concentrations in male rats. METHOD: Male rats were divided into four groups as follows: Group (i): DOCA-Salt for 12 weeks; Group (ii): Solvent of DOCA injection for 12 weeks; Group (iii): DOCA-Salt for 12 weeks and DOCA-Salt withdrawal for 12 weeks; Group (iv): Solvent of DOCA injection for 12 weeks and its withdrawal for 12 weeks. At the end of experiment, serum NO concentrations were measured and vascular permeability in aorta and coronary circulation were evaluated using Evans Blue dye method. RESULTS: RESULTS showed that systolic blood pressure was significantly higher in DOCA-Salt hypertensive rats compared to normotensive group (150.1±2.42 vs. 97.7±2.32mmHg, respectively). DOCA-Salt withdrawal completely reduced blood pressure in hypertensive rats to normotensive level (150.1±2.42 vs. 98.1±3.68mmHg, respectively). Coronary vascular and aortic endothelial permeability were not different between DOCA-Salt hypertensive and normotensive rats and reversal of blood pressure did not alter it. Serum NO level was significantly lower in the hypertensive animals compared to normotensive group (3.87±0.97 vs. 7.71±0.67µmol/l) and blood pressure reduction returned serum NO level to normotensive level (7.25±0.96 vs. 7.71±0.67µmol/l). CONCLUSION: DOCA-Salt hypertension and its reversal did not alter coronary vascular and aortic endothelial permeability. However, serum NO level was significantly reduced during hypertension and reversal of hypertension completely reduced blood pressure together with the restoration of serum NO concentration. This may suggest that biological marker of endothelial function do not behave uniformly at least in this model of hypertension.

Electrical stimulation of nucleus raphe dorsalis changes morphine self-administration and withdrawal symptoms in rats.

The involvement of antero-dorsal part of the nucleus raphe dorsalis (NRD) in motivational aspects of drug-taking behaviour during initiation of drug self-administration was investigated using a recently developed behavioural paradigm. In separate experiments animals were allowed to self-administer morphine (1 mg/kg per inf) ten consecutive daily 3-h sessions. During all morphine self-administration sessions lever-press behaviour was measured in absence of electrical stimulation of NRD, as an index of the motivational aspects involved in drug-taking behaviour. The electrical stimulation (pulse 0.5 ms, 150 &mgr;A, 20 Hz) of NRD 30 min before morphine self-administration produced a significant decrease in the initiation of morphine self-administration during all sessions (reduced number of lever-press behaviour). After the last test session, morphine withdrawal syndrome signs (wet dog shakes, jumping, writhing and diarrhoea) in the naloxone-induced behaviour were measured. Our results showed that these withdrawal syndrome signs decreased by application of electrical stimulation in NRD, in comparison with morphine groups. It is concluded that serotonergic system in the NRD might be involved in the motivational processes underlying morphine self-administration.