Action Potentials ; Animals ; Female ; Male ; Nifedipine ; pharmacology ; Rabbits ; Ureter ; drug effects ; physiology ; Urination ; drug effects ; Vitamin K 3 ; pharmacology

OBJECTIVETo explore the in vitro anti-platelet effects of Ginsenoside -2A,a purified extract from Panax notoginseng.

METHODSPlatelet rich plasma (PRP) was prepared routinely from venous blood samples of patients with essential hypertension and normal persons. PRP was incubated with different concentrations of Nifedipine, Ginsenoside-2A ,and SK&F96365. Maximal platelet aggregation rate[ PAG (M) ] induced by 2 micromol/L ADP was taken as the observed index. Five-minute PAG( M) was determined for 5 consecutive times.

RESULTS(1) PAG (M) in essential hypertension group was 0. 89 +/- 0. 06, which was higher than that in the normal group (0. 68 +/-0. 07 ) with significant difference (P <0.01). (2)Nifedipine of two concentrations (10 p.mol/L,20 pVmol/L) had no effect on PAG(M) in either essential hypertension group or normal group(P >0. 05). (3)Different concentrations of SK&F96365 (2.5 micromol/L,5 micromol/L,10 micromol/L and 20 micromol/L) could inhibit the PAG(M) in essential hypertension group; (4) Differen concentrations of Ginsenoside -2A (2. 5 micromol/L, 5 micromol/L, 10 micromol/L and 20 micromol/L) could inhibit PAG ( M) in essential hypertension group; three concentrations of Ginsenoside -2A (5 micromol/L, 10 micromol/L, 20 micromol/L) could inhibit the PAG(M) in the normal group (all P <0.05).

CONCLUSIONPlatelet aggregating function in essential hypertension patients was obviously higher than that in the normal persons and platelets was in the high reactive status. Nifedipine had no inhibitive effect on platelet aggregation. SK&F96365 could inhibit the platelet aggregation. Ginsenoside-2A could inhibit platelet aggregation, and had the definite anti-platelet action.

Drugs, Chinese Herbal ; administration & dosage ; pharmacology ; Ginsenosides ; administration & dosage ; pharmacology ; Humans ; Imidazoles ; administration & dosage ; pharmacology ; Nifedipine ; administration & dosage ; pharmacology ; Platelet Aggregation Inhibitors ; administration & dosage ; pharmacology

OBJECTIVETo investigate the effect of nifedipine of therapeutic dosage on the plasma membrane functional integrity and osmosensitive calcium influx in human sperm in vitro.

METHODSSperm samples were aseptically obtained from 10 healthy fertile men by masturbation and prepared by swim-up technique to produce a spermatozoal solution of high motility. The solution was then incubated with nifedipine of 20, 100 and 20 x 10(3) ng/ml respectively at 37 degrees C in vitro. The hypo-osmotic swelling (HOS) test was done to assess the sperm function. Intracellular calcium concentration was measured by fluorescent probe fura-2/AM before and after sperm medium dilution in distilled water.

RESULTSThe 20 x 103 ng/ml group showed significantly lower HOS scores than the control (P < 0.01). The 20, 100 and 20 x 10(3) ng/ml groups all showed significantly lower Ca2+ fluorescence D-value than the control (P < 0.01).

CONCLUSIONNifedipine can modify plasma membrane functional integrity and inhibit osmosensitive calcium influx in human sperm and affect male fertility in vitro in therapeutic dose.

Adult ; Calcium ; metabolism ; Cell Membrane ; Humans ; In Vitro Techniques ; Male ; Nifedipine ; pharmacology ; Osmotic Pressure ; Spermatids ; drug effects ; metabolism ; physiology

OBJECTIVETo study the cytotoxicity of maitotoxin (MTX) and its protective effects on calcium-channel blocking agents, so as to provide the data for control and treatment of MTX poisoning.

METHODSCytotoxicity was measured by MTT detecting system, and cytoplasmic free [Ca(2+)]i was measured by F-4500 fluorometry.

RESULTSIncubation with 8 ng/ml MTX for 3 h reduced the survival ratio of LLC-PK(1) cells. The response was found in a time- and concentration-dependent manner, with significant differences as compared with the control group. The MTX-induced increase in [Ca(2+)]i was inhibited by Verapamil and Nifedipine at 5 x 10(-5) mol/L and 1 x 10(-4) mol/L respectively. Both of them significantly reduced the death of the LLC-PK(1) cells.

CONCLUSIONSCytotoxicity of MTX may be caused by the elevated intracellular [Ca(2+)]i. Calcium-channel blocking agents could protect LLC-PK(1) cells from injury by MTX.

Animals ; Calcium ; metabolism ; Calcium Channel Blockers ; pharmacology ; Drug Antagonism ; LLC-PK1 Cells ; Marine Toxins ; toxicity ; Nifedipine ; pharmacology ; Oxocins ; Swine ; Verapamil ; pharmacology

AIMTo discover new regulators of potassium channel, an in vitro assay based on DiBAC4 (3) to determine the fluorescence was established for high throughput screening.

METHODSA cell-based 96-well format fluorescence assay using DiBAC4 (3) in cultured PC12 cells was described. Cells were loaded with 5 mumol.L-1 DiBAC4 (3) and incubated at 37 degrees C for 30 min before adding KCl or several known potassium channel regulators. The cellular DiBAC4 (3) fluorescence responce was then detected. The fluorescence changes can be used to evaluate membrane potential changes, which are determined mainly by potassium channels.

RESULTSExtracellular high K(+)-induced depolarization and several potassium channel blockers including 4-AP, TEA, E-4031, glibenclamide, quinidine and nifedipine all evoked increases in DiBAC4 (3) fluorescence response. The potassium channel opener, cromakalim, evoked decrease in DiBAC4 (3) fluorescence response. The fluorescence changes of 4-AP, TEA, glibenclamide, nifedipine and cromakalim were in a concentration-dependent manner. In 76 compounds screened by using the established DiBAC4 (3)-based assay, 9 compounds were found to change the fluorescence dose-dependently. Patch clamp technique is needed to further testify and screen their actions on potassium currents.

CONCLUSIONThe DiBAC4 (3)-based assay is easily operated, economical and repeatable. So, it can be performed by high throughput screening for potassium channel regulators.

4-Aminopyridine ; pharmacology ; Animals ; Barbiturates ; chemistry ; Calcium Channel Blockers ; pharmacology ; Cromakalim ; pharmacology ; Isoxazoles ; chemistry ; Membrane Potentials ; drug effects ; Nifedipine ; pharmacology ; PC12 Cells ; Patch-Clamp Techniques ; Piperidines ; pharmacology ; Potassium Channel Blockers ; pharmacology ; Potassium Channels ; drug effects ; Pyridines ; pharmacology ; Quinidine ; pharmacology ; Rats

OBJECTIVETo explore the effects of 2A-1-1 (purified component from Panax notoginsengs saponins) on the aggregation of and Ca2+ influx into human platelets.

METHODSThe aggregation of platelets was tested by nephelometry, Fura-2 fluorescent technique was used for detecting cell [Ca2+]i. The effects of 2A-1-1, nifedipine and SK&F96365 on Ca(2+) influx into human platelets induced by ADP or CPA were observed separately.

RESULTSNifedipine (< 20 micromol/L) could not inhibit platelet aggregation induced by ADP or the Ca(2+) influx induced by ADP or CPA. SK&F96365 at 20 micromol/L could inhibit the maximal aggregation of platelets induced by ADP with a inhibitory rate of 59.83%, at 15 micromol/L could inhibit the Ca2+ influx induced by CPA or ADP. 2A-1-1 (5, 10 and 20 micromol/L) could inhibit the maximal aggregation of platelets induced by ADP with the inhibitory rates of 47.06%, 53.47% and 71.52%, respectively. 2A-1-1 at 10 and 20 micromol/L could inhibit the Ca2+ influx induced by CPA or ADP.

CONCLUSIONS2A-1-1 can inhibit platelets aggregation, block the ROC (Receptor-dependent Ca2+ channels) and inhibit Ca2+ influx of human platelets.

Adenosine Diphosphate ; pharmacology ; Adult ; Blood Platelets ; cytology ; drug effects ; metabolism ; Calcium ; metabolism ; pharmacokinetics ; Calcium Channel Blockers ; pharmacology ; Dose-Response Relationship, Drug ; Female ; Ginsenosides ; pharmacology ; Humans ; Imidazoles ; pharmacology ; Indoles ; pharmacology ; Male ; Nifedipine ; pharmacology ; Platelet Aggregation ; drug effects ; Platelet Aggregation Inhibitors ; pharmacology

AIMTo study unitary-core osmotic pump tablet for delivering water-insoluble drug for 24 hours.

METHODSUnitary-core osmotic pump tablet was prepared using nifedipine as the model drug. The effects of various core formulation variables on drug release were studied.

RESULTSPolyethylene oxide and potassium chloride have comparable positive effects on drug release, whereas, nifedipine has markedly negative effect on drug release.

CONCLUSIONUnitary-core osmotic pump tablet is very easy in preparation and it can deliver water-insoluble drug in substantially constant rate for 24 hours.

Calcium Channel Blockers ; administration & dosage ; chemistry ; Delayed-Action Preparations ; Drug Delivery Systems ; Nifedipine ; administration & dosage ; chemistry ; Osmosis ; Polyethylene Glycols ; pharmacology ; Potassium Chloride ; pharmacology ; Solubility ; Tablets ; Technology, Pharmaceutical ; methods

BACKGROUNDTamsulosin, an alpha-1 receptor antagonist, has been demonstrated effective in promoting distal ureteral stone passage and in reducing pain associated with stone expulsion. This study aimed to evaluate the effect of tamsulosin in comparison with nifedipine and extracorporeal shock wave lithotripsy (ESWL) on the expulsion rate of distal ureteral stones at different sizes.

METHODSWe assigned 314 patients to three categories: I, the stone with maximal diameter of 4.0 - 5.9 mm; II, 6.0 - 7.9 mm, and III, 8.0 - 9.9 mm. Patients in each category were randomly subdivided into three treatment subgroups: group A (nifedipine group), group B (tamsulosin group), and group C (ESWL group). Stone-free rate and the dose of analgesics were recorded weekly during the 4-week follow-up period.

RESULTSThree hundred and three patients completed the study. The results showed that nifedipine and tamsulosin treatments promoted a small (4 - 8 mm, categories I and II) stone expulsive rate that was comparable with ESWL treatment. Nonetheless, when the stone diameter was 8.0 - 9.9 mm, ESWL showed a greater stone free rate than nifedipine and tamsulosin treatments; no significant difference existed between the latter two therapies. Although the ESWL treatment group required the least analgesics, tamsulosin treatments required less pain medication than nifedipine (P < 0.05).

CONCLUSIONSTamsulosin treatment is recommended for patients with the stone diameter smaller than 8 mm because of its feasibility, effectiveness and safety. ESWL is more appropriate than tamsulosin therapy for the patients whose stones are larger than 8 mm.

Adrenergic alpha-Antagonists ; pharmacology ; Adult ; Calcium Channel Blockers ; pharmacology ; Female ; Humans ; Lithotripsy ; Male ; Middle Aged ; Nifedipine ; therapeutic use ; Sulfonamides ; therapeutic use ; Treatment Outcome ; Ureteral Calculi ; drug therapy ; therapy

OBJECTIVETo investigate the effect of nifedipine on the non-selective inward current of cochlear Hensen cell induced by ATP in high concentrations.

METHODSThe organ of Corti was treated using enzyme, and then dissociated mechanically to isolate Hensen cells. The whole cell patch-clamp technique was used to record ion currents in Hensen cells which had integrated border, round shape and translucent intracellular cytoplasm. Drugs were delivered to the cell by a micro-manifold consisting made by three 100 microm diameter microtubules, including 0.1 mmol/L ATP, 1 mmol/L ATP, 10 mmol/L ATP, 0.1 mmol/L ATP + 0. 1 mmol/L suramin (purinergic antagonist), stimulation of extracellular fluid alone, 140 mmol/L CsCl (replace KCL in intracellular fluid) + 1 mmol/L ATP, 40 mmol/L TEA (blocker of potassium channel) + 1 mmol/L ATP, and 1 mmol/L ATP + 10 micromol/L nifedipine, respectively.

RESULTSWhen isolated Hensen cell was given 0.1 mmol/L (n = 10), 1 mmol/L (n = 10), 10 mmol/L( n = 6) ATP separately, an inward ion current could be recorded, which enhanced with increased ATP concentration and showed dose-dependence. Further study indicated that the inward ion current could be inhibited by 0.1 mmol/L suramin (n = 5), 140 mmol/L CsCl (n = 5) and 40 mmol/L TEA (n = 5). There was no ion current be recorded when the cell was stimulated with the extracellular fluid alone, neither inward nor outward. However, the inward ion current vanished and an outward ion current appeared instead, when 1 mmol/L ATP and 10 micromol/L nifedipine were given together (n = 5).

CONCLUSIONSAn inward current was evoked in isolated Hensen cell by ATP in high concentrations. This inward current seems to be associated closely with potassium channels without the participation of mechanical channels. Nifedipine can inhibit this inward current and induce an outward current, which is similar to the normal potassium current in isolated Hensen cell. It suggests that nifedipine have partly protective effect on the function of cochlea by inducing modulate of the potassium circle of cochlea in Hensen cell's tache.

Adenosine Triphosphate ; pharmacology ; Animals ; Cochlea ; cytology ; Female ; Guinea Pigs ; Labyrinth Supporting Cells ; drug effects ; metabolism ; Male ; Nifedipine ; pharmacology ; Patch-Clamp Techniques ; Potassium Channels, Inwardly Rectifying ; drug effects

Apoptosis Regulatory Proteins ; physiology ; Autophagy ; drug effects ; Calcium Channel Blockers ; pharmacology ; Female ; Humans ; Membrane Proteins ; physiology ; Nifedipine ; pharmacology ; Signal Transduction ; physiology ; TOR Serine-Threonine Kinases ; physiology