The study assessed the hydroalcohol extract effects of Crocus sativus L. (saffron) on (i) the basic and rate-dependent electrophysiological properties of the AV node, (ii) remodeling of the AV node during experimental atrial fibrillation (AF) and (iii) the role of nitric oxide (NO) in the effects of saffron on the AV node. Stimulation protocols in isolated AV node were used to quantify AV nodal recovery, facilitation and fatigue in four groups of rabbits (n = 8-16 per group). In addition, the nodal response to AF was evaluated at multiple cycle lengths and during AF. Saffron had a depressant effect on AV nodal rate-dependent properties; further, it increased Wenckebach block cycle length, functional refractory period, facilitation and fatigue (p < 0.05). A NO-synthase inhibitor (L-NAME) prevented the depressant effects of saffron on the AV node (p < 0.05). Saffron increased the zone of concealment in experimental AF (p < 0.05). The present research showed, for the first time, established electrophysiological remodeling of the AV node during AF by saffron. Saffron increased the AV nodal refractoriness and zone of concealment. These depressant effects of saffron were mediated by endogenous NO.

Doctors with longer consultation times tend to diagnose illnesses more precisely, prescribe fewer drugs and present better health advice to their patients. The aim of this study was to measure the average consultation time of general practitioners in Gorgan, Islamic Republic of Iran and to investigate the factors affecting consultation length, especially in relation to rational prescribing of drugs. Data were collected on 620 patient consultations with 62 randomly selected general practitioners. Mean consultation length was 6.9 (SD 2.6) minutes. Patient factors that were significantly associated with a longer mean duration of consultation time were: higher number of health problems, older age and fewer items of previously used drugs. Physician factors that were significantly associated with a longer mean consultation time were: younger age, higher numbers of items prescribed and injectable drugs prescribed, frequency of interruptions and higher workload.

A few studies explored the atrioventricular (AV) nodal effects of 5-hydroxytyptamine (serotonin, 5-HT) during supraventricular tachyarrhythmia. The aims of the present study are to investigate (i) 5-HT effects on the rate-dependent electrophysiological functions of AV node during atrial fibrillation (AF) and (ii) the potential contribution of various 5-HT receptors and the role of the autonomic nervous system on 5-HT effects on AV nodal properties. The specific stimulation protocols were applied to detect the electrophysiological parameters of AV node in seven groups of isolated rabbit AV nodal preparations (N = 75) in the presence of 5-HT (0.5, 1, 5, 10, and 20 μM) and its receptor antagonists, nadolol and atropine. The simulated AF protocol was executed in a separate group, and specific indices, including mean His-His interval, a zone of concealment (ZOC), and concealed beats recorded. 5-HT (10-20 μM) increased significantly functional refractory period, Wenckebach cycle length, and excitability index (p < 0.05). The percentage of gap and echo beats was significantly decreased with increasing 5-HT concentrations (p < 0.05). Ketanserin and tropisetron increased significantly atrial-His conduction time, effective refractory period, and Wenckebach cycle length (p < 0.05). 5-HT effects on functional refractory period and Wenckebach cycle length were abrogated by tropisetron and nadolol (p < 0.05). 5-HT elicited prolongation of ZOC and nodal refractoriness (p < 0.05). We conclude that 5-HT elicited prolongation of the nodal refractoriness more than atrial-His conduction time leads to increase in the excitability index and ZOC without significant reduction of the ventricular rates during AF.

Introduction: Previous studies revealed anti-inflammatory and anti-spasmodic effects of Matricaria recutita. The objective of present study is to determine: 1) the effect of spray dried total extract of M. recutita collected in Golestan province of Iran on contractile phase of isolated jejunum of rabbit 2) the role of Cholinergic and Nitregic systems on anti-spasmodic effects of M. recutita.\ud Material &Methods: In first groups (N=6), the effects of increasing concentrations of plant extract on the contractile responses of jejunum of rabbits induced by cumulative addition of extracellular calcium and high K+ were studied. The role of the nitrergic and cholinergic systems was assessed in the presence of various concentrations of M. recutita (0.003–0.013mg/ml) and cholinerhic and nitrergic modulators at the second and third groups (N=12).\ud Results: Significant concentration-dependet inhibitory effects of M. recutita on contraction of smooth muscle caused by cumulative concentrations of calcium (0.03–3 mM) and to 50 mM Kcl was observed. Pretreatments with L-Name (100µm) and atropine (3µm) abrogated effectively the spasmolytic effect of M. recutita. Although, the M. recutita effect was significantly reduced in preparations pretreated with L-Argening (100mM), a precursor of Nitric Oxide production. Interestingly, contractile response of smooth muscle to Ach was completely reverted by M. recutita\ud Conclusion:Our results indicate that the anti-spasmodic effects of Matricaria recutita arise from its direct inhibitory effects on Ca2+ channels. however, modulation of cholinergic and nitregic pathway could be involved. These observations suggest that Matricaria recutita inhibit contractile elements of peristalsis by facilitating inhibitory role of nitrergic pathway