laxative and prokinetic effects of Rosa damascena mill in rats

This study was aimed to assess the possible laxative and prokinetic effects of the boiled extract of Rosa damascena. Rats in two groups [n= 7] of test and control were gavaged either with the extract or placebo, respectively. The number, weight and water percentage of feces were studied up to 24 hr. In order to assess the possible osmotic laxative effects of the drug, the jejunum in anesthetized rats [n= 7] was randomly divided into 4 cm segments and 0.5 ml of the extract, lactulose or saline was injected in each segment. The volumes of the contents in each segment were measured after 1 hr. In order to assess the intestinal transit time, fasting rats were gavaged with either the extract or placebo. Thirty minutes following the last medication, all rats were gavaged with phenol red and methyl cellulose [1.5 ml]. The test and the control rats, in groups of 4, were sacrificed at 30 min, 1, 2 and 4 hr, and the amounts of the phenol red in various parts of the gastrointestinal tract were measured. Boiled extract of R. damascena significantly increased feces number and its percentage of water, but had no effects on the transit time of intestinal ingesta. The volume of the contents in jejunum segments had significantly increased with the extract or lactulose compared to placebo. Boiled extract of R. damascena apparently exerts its laxative effects, at least in part, via osmotic infiltration of fluids into the intestine

Does heart affect peripheral vascular resistance following myocardial ischemia and reperfusion?

The aim of this study was to investigate the overall effect of cardiac vasoactive factors during coronary occlusion and reperfusion on peripheral vascular tone, using a sequential isolated rabbit heart-ear perfusion model. Isolated ears were perfused with the effluent of isolated hearts subjected to ischemia [30 min] and reperfusion [180 min, n=6]. The comparator groups consisted of a sham operated group [no ischemia, n=5] and the ears that were directly perfused with modified Krebs [n=10]. At the end of previous experiment, the perfusion mode of the sequentially perfused ears was converted to non-sequential perfusion with modified Krebs for 10 min and vice versa. In a separate experiment, samples collected from heart effluent during different stages of the first experiment were perfused to isolate stabilized ears [3 min; n=5] or hearts [1 min; n=5]. The possible effects of the samples on the tone of isolated femoral artery rings were also studied using an organ bath [n=5]. Coronary occlusion and reperfusion did not exert significant effects on the heart rate or the perfusion pressure of the sequentially perfused ears. The samples collected during different stages of ischemia and reperfusion did not affect the vascular tone in isolated ears or femoral artery rings either. The current study suggests that isolated heart, even following ischemia and reperfusion, does not release vasoactive substances in concentrations sufficient enough to affect peripheral resistance