AIM To investigate the positive inotropic effect of aconitine on isolated hearts from cardiac dysfunctional rats when combined with pinacidil. METHODS In our experiment Langendorff perfusion equipment was used to investigate the following cardiac indexes:LVSP(left ventricular systolic pressure), LVDP(left ventricular diastolic pressure), +d p /d t max (the maximum going up rate of left ventricular pressure) and -d p /d t max (the maximum going down rate of left ventricular pressure) from rat hearts under two conditions:① aconitine only,② aconitine plus pinacidil(an agonist of K ATP channel) to observe the positive inotropic effect of aconitine on cardiac dysfunctional rat hearts. RESULS ①Aconitine had certain positive inotropic effect on isolated hearts from cardiac dysfunctional rats; ②Combing aconitine with potassium channel activator markedly winded the doses range between the effective and toxic concentration and enhanced the cardiotonic effect of aconitine. CONCLUSION Aconitine had positive inotropic effect on dysfunctional isolated rat hearts; the combination of aconitine with potassium channel activator markedly widened the cardiotonic doses range of aconitine and enhanced its cardiotonic effect.

1∶640) was purified by affinity chromatography with a Mab Trap kit.The effects of the purified IgGs on the ion channel and transporter(INa/Ca,INa pump,ICa-L,Itko,Ik1,IK) at concentrations of 10 nmol/L,20 nmol/L and 40 nmol/L were observed by whole cell voltage clamp technique.RESULTS:The purified IgG enhanced INa/Ca,ICa-L and I Na/k pump in a dose-dependent manner and no significant effect on INa,Itko,Ik1 and Ik was found.CONCLUSION:The site specific antibody of Na-Ca exchanger stimulates Na-Ca exchanger current and has cross-reaction with L-type Ca channel and Na pump.

150 ml in 22 patients (31%).Ten patients (14%) had detru-sor instability.Six patients were incapable to void during the test. The volume of first bladder sensation was(203.25?107.53)ml (range,125 -630 ml) in the diabetes patients.The bladder capacity was (428.09?227.89)ml (range,220 -1350 ml).The maximum flow rate was (10.70?3.27) ml/min.The residualurine volume was (100.57?108.08) ml.In early stage group the volume of first bladder sensation was(151.67?24.07) ml;while in progressive stage group it was (268.16?13.90)ml,and bladder capacitywas (592.97?252.51)ml.The maximum flow rate was (8.61?2.04) ml/min. PQmax was (33.16?19.81)cm H2O (1 cm H2O=0.098 kPa).The residual urine volume was (169.03?137.25) ml. Theseparameters were all abnormal. In the detrusor strips test,the threshold of the tension which made the detrusorstrips contract was significantly higher in T2DM rats [(0.72?0.33) g] than in control rats [(0.32?0.18)g] (F=59.63,P

AIMTo elucidate possible mechanisms underlying the differences between 1S-[1a,2b,3b,4a(S*)]-4-[7-[[1-(3-chloro-2-thienyl)methylpropyl]propyl-amino]-3H-imidazo[4,5-b]pyridyl-3-yl]-N-ethyl-2,3-dihydroxycyclopentane carboxamide (AMP- 579) and adenosine in pharmacological and clinical effects. METHODSNa+/Ca2+ exchange current was recorded by patch-clamp technique in whole-cell configuration. RESULTSAMP579 significantly enhanced both outward and inward Na+/Ca2+ exchange currents in a concentration dependent manner. Neither infusion of an adenosine A1 receptor antagonist PD116948 30 μmol*L-1 or an adenosine A2 receptor antagonist DMPX 10 μmol*L-1 nor a protein kinase A special blocker KT 5720 0.2 μmol*L-1 or a protein kinase C special blocker GF 109203X 0.4 μmol*L-1 had effect on Na+/Ca2+exchange current increased by AMP579, suggesting that AMP579 possess a direct activating effect on Na+/Ca2+ exchange current. CONCLUSIONAMP579 possibly possesses a direct activating effect on Na+/Ca2+ exchange current.

AIM　To study the effects of Phe-Met-Arg-Phe-NH2 (FMRFa) on Na+/Ca2+ exchange and its specificity for Na+/Ca2+ exchange in rat ventricular myocytes. METHODS　Na+/Ca2+ exchange current and other currents of ion channels were measured using whole cell voltage clamp techniques. RESULTS　A dose-related inhibition of tetrapeptide FMRFa on Na+/Ca2+ exchange was observed in rat ventricular myocytes. Inward and outward INa+/Ca2+ were inhibited by 60.1% and 56.5%, respectively, at highest concentration (100 μmol*L-1) and its IC50 were 20 μmol*L-1 and 34 μmol*L-1 in inward and outward INa+/Ca2+, respectively. Inward and outward INa+/Ca2+ were inhibited 38.7% and 34.9%, respectively, at FMRFa 5 μmol*L-1. FMRFa 5 μmol*L-1 and 20 μmol*L-1 did not affect L-type calcium current, sodium current, transient outward current and inward rectifier potassium current. CONCLUSION　These data indicate that FMRFa is a specific inhibitor of Na+/Ca2+ exchange in intact rat ventricular myocytes.

Aim This paper aims at investigating the effect of dofetilide on Na+/Ca 2+exchange in ventricular myocytes of adult guinea pigs. Methods Rapid enzymatic isolation procedure was performed to get single ventricular myocytes from adult guinea pigs. After the whole cell configuration was formed, a ramp voltage-clamp pulse depolarized from a holding potential of -40 mV to +60 mV, then hyperpolarized to -120 mV at a rate of 90 mV/s to record the Na+/Ca 2+ exchange current (I Na/Ca) and the influence of dofetilide from 0.03～1.0 ?mol?L -1. Result Dofetilide from 0.03～1.0 ?mol?L -1 concentration-dependently increased the I Na/Ca in both outward and inward mode. The EC 50 of dofetilide on I Na/Ca in outward and inward mode of NCE was 0.178 ?mol?L -1 (95% confidence interval was 0.040～0.787 ?mol?L -1) and 0.178 ?mol?L -1 (95% confidence interval was 0.038～0.842 ?mol?L -1), respectively. Conclusion Dofetilide concentration-dependently increased the outward and inward Na+/Ca 2+ exchange current in ventricular myocytes of adult guinea pigs.

Aim To investigate the effects of 5-HT_4 receptor agonist and 5-HT_3 receptor antagonist 2-[1-(4-piperonyl)piperazinyl]benzothiazole on rat heart rhythm and the involved ionic mechanisms.Methods Langendorff-perfused rat hearts were subjected to 0.1～10 μmol·L~(-1) 2-[1-(4-piperonyl)-piperazinyl]benzothiazole for 15 minutes with simultaneous ECGs recording.The whole-cell patch-clamp electrophysiology was used to record effects of 2-[1-(4-piperonyl)piperazinyl]benzothiazole on inward rectifier K~+ current(I_(K1)),transient outward K~+ current(I_(to)),resting membrane potential(RMP)and action potential(AP)in enzymatic dissociated rat ventricular myocytes.Results In ex vivo Langendorff-perfused hearts,0.1～10 μmol·L~(-1) 2-[1-(4-piperonyl)piperazinyl]benzothiazole elicited singnificant rhythm disturbances.In the presence of 10 μmol·L~(-1) agent,the total of PVB were 236±37,87.5%(7/8)hearts exhibited VT,and 62.5%(5/8)hearts exhibited VF(P<0.01).At the concentration of 0.1～10 μmol·L~(-1),2-[1-(4-piperonyl)piperazinyl]benzothiazole could inhibit I_(K1)(EC50=0.74 μmol·L~(-1))and I_(to)(EC50=2.16 μmol·L~(-1)),decrease RMP and prolong action potential duration(APD)in concentration-dependent manners(n=6,P<0.01).Conclusion Inhibition of IK1,Ito and resultant prolongation of APD,depolarization of RMP might be the critical causes for induction of arrhythmias by 2-[1-(4-piperonyl)piperazinyl]benzothiazole in rat.

Aim To assess the effects of N -[2-p-bromo-cinnamylamino-ethyl]-5-isoquinoline-sulfonamide (H-89), a potentially selective inhibitor of Protein Kinase A (PKA), on cardiac membrane ion channels and transporters, which will further fulfill our understanding of pharmacology of PKA inhibitors.Methods Whole-cell patch clamp was used to investigate the effects of H-89 on cardiac L-type Ca~(2+) current (I_(Ca-L)), Na~+ current (I_(Na)), inward rectifier K~+ current (I_(K1)), transient outward K~+ current (I_(to)) and Na~+-Ca~2+ exchanger current (I_(Na/Ca)) in enzymatic dissociated SD rat ventricular myocytes.Results H-89 at 1～10 μmol·L~(-1) could inhibit I_(Ca-L) , I_(Na) , and Ito in a concentration-relative manner (P <0.05). At low concentra-tion (5 μmol·L~(-1)), H-89 completely inhibited I_(K1) (P <0.05) just as the action of 0.5 mmol·L~(-1) BaCl_2.Further, H-89 at 1～10 μmol·L~(-1) had no significant effect on I_(Na/Ca) (P >0.05).Conclusion The direct or PKA-mediated indirect action maybe involved in the effects of H-89 on ion currents and transporter.

Objective:To observe the effects of active immunization with a synthesized repetitive peptides in the extracellular loops of Na/Ca exchanger(NCX)?1 on cardiac structure and function in rats.Methods:A repetitive peptide of 124 HNFTAGDLGPSTIVGSAAFNMF145 was synthesized,which was in line with the extracellular loops of Na/Ca exchanger(NCX)?1.Healthly male Wistar rats of 2 month age were immunized actively with the synthesized peptide as antigen repeated for 12 weeks.The control group was given Freund's adjuvant only.Specific antibodies were detected by ELISA.The cardiac function was observed by Langendorff isolated heart-perfusing assay and the hearts were prepared for routine histological evaluation.Results:All rats immunized with the peptide developed highly positive autoimmunities,indicated by the antibody titers.After 12 weeks of peptide inoculation,the cardiac functioning indexes including LVSP-LVDP,+dp/dtmax and -dp/dtmax increased much more significantly in immunized group than in control.Histological evaluation showed that the myofilaments of the control group arranged regularly and densely with better continuity,whereas the myofilaments of the immunized group were lined with disorder.Some of those were ruptured.The interstitial lymphocyte infiltration was observed.Conclusion:The results indicate that long term immunization with the synthesized repeatitive peptide in line with the extracellular parts of Na/Ca exchanger(NCX)?1 can enhance both systolic and diastolic function of rat heart,but it can also induce injury in the heart structure.This may relate with an increase of myocardial oxygen consumption owing to a long time and continued excitement of membrane ion transporters as well as their active effect in heart contraction to a larger extent.

0.05).Zacopride at concentration of 1.0 ?mol/L showed the most potent activity on IK1 with approximately 30% increment both in inward current and outward current(P