Zhongguo yao li xue bao = Acta pharmacologica Sinica最新文献

Aim: To detect inositol 1,4,5-triphosphate (IP3) formation of pregnant and nonpregnant human myometrial cells induced by acetylcholine (ACh).

Methods: [3H] IP3 competitive protein binding assay.

Results: Basal levels of IP3 in pregnant and nonpregnant human myometrial cells were (82 +/- 9) and (96 +/- 10) nmol.g-1 (protein), respectively (n = 6). Incubated with ACh 50 mumol.L-1 for 5 min, IP3 reached the peak levels (109 +/- 11) and (122 +/- 15) nmol.g-1 (protein), respectively (n = 6), but difference of the increments of IP3 in pregnant and nonpregnant women was not significant. The increased IP3 induced by ACh was inhibited by atropine (Atr) 1 mumol.L-1.

Conclusion: The basal IP3 level in pregnant cervix myometrial cells was higher than that in nonpregnant women. ACh increased the IP3 formation.

Aim: To study the inhibitory effects of sodium quercetin monosulfate (SQMS) on pig platelet aggregation induced by thrombin.

Methods: Platelet aggregation was analyzed by turbidimetry. Cytosolic free calcium concentration ([Ca2+]i) was determined by Fura-2 fluorescence. Activity of protein kinase C (PKC) was assayed by incubating PKC with histone III S and [gamma-32 P] ATP. The cytoskeletal proteins were precipitated by Triton X-100 and separated by SDS-PAGE.

Results: SQMS inhibited the platelet aggregation induced by thrombin 500 U.L-1 with IC50 132 (50-347) mumol.L-1. SQMS inhibited Ca2+ influx in blood platelets induced by thrombin 500 U.L-1 in the presence of extracellular Ca2+ 1 mmol.L-1 with IC50 20 (9-46) mumol.L-1; SQMS inhibited the internal Ca2+ release in the absence of extracellular Ca2+. SQMS also decreased [Ca2+]i level in quiescent blood platelets. SQMS (10-160 mumol.L-1) inhibited the activity of cytosolic PKC from blood platelets in a concentration-dependent manner, but had no effect on membrane PKC. SQMS (20-80 mumol.L-1) inhibited the actin polymerization induced by thrombin 500 U.L-1 inblood platelets in a concentration-dependent manner.

Conclusion: SQMS inhibited pig platelet aggregation induced by thrombin and its mechanism might be due to its inhibitions of Ca2+ influx, internal Ca2- release, PKC activity, and actin polymerization.

Aim: To analyze the target selective and sequence-specific inhibitory effect of mitogen-activated protein kinase (MAPK) phosphorothioate antisense oligodeoxynucleotides (ODN) on p42/p44, p38 MAPK, c-jun NH2-terminal protein kinases (JNK) protein expression, and DNA synthesis in vascular smooth muscle cell (VSMC).

Methods: Using a phosphorothioate-protected 17-mer antisense MAPK ODN directed against the initiation of translation sites of the p42/p44 MAPK isoforms by liposomal transfection to deplete cultured rat, rabbit, and fetal calf VSMC MAP kinases. The 17-mer sense and random sequence MAPK ODN were used as controls. After liposomal transfection, cells were exposed to 20% serum for 24 h, and then harvested in lysis buffer. P42/p44, p38 MAPK, and p46/p58 JNK protein expression were measured by Western blot. DNA synthesis was measured by [3H]thymidine incorporation.

Results: Treatment with MAPK antisense ODN (0.1-0.8 mumol.L-1) for 48 h reduced phosphored p42/p44 MAPK protein expression but without effect on p38 MAPK and JNK expression, and inhibited cultured rat, rabbit, and fetal calf VSMC [3H]thymidine incorporation stimulated by 20% serum in a concentration-dependent manner.

Conclusion: The MAPK antisense ODN target-selectively and sequence-specifically reduces the p42/p44 MAPK protein expression and concentration-dependently inhibits proliferation of rat, rabbit and fetal calf VSMC.

Aim: To investigate whether diacylglycerol (Dia) signaling pathway is stimulated by advanced glycosylation end products (AGEP) and to determine effect of vitamin E and aminoguanidine on Dia level induced by AGEP in cultured rat aortic vascular smooth muscle cells (VSMC).

Methods: The effect of AGEP on Dia level in cultured VSMC was measured by radio-enzymatic assay. Quantitative measurements of [32P]phosphatidic acid were performed by thin-layer chromatography and autoradiography.

Results: The Dia level in VSMC incubated with AGEP-BSA was markedly increased in a concentration-dependent, biphasic manner. The early phase was rapid and transient, peaking at 15 s. The late phase reached the maximal level at 10 min and decayed slowly. The Dia levels in VSMC exposed to different concentrations of AGEP-BSA and AGEP-BSA glycosylated for various periods were greatly increased compared with control group. Vitamin E 50, 100 nmol.L-1 prevented the AGEP-BSA-stimulated elevation of Dia level in VSMC, from (940 +/- 43) pmol.L-1 to (599 +/- 38), (290 +/- 21) pmol.L-1, respectively. In aminoguanidine-treated AGEP-BSA groups, Dia level in the cells incubated with the same concentration of AGEP-BSA (100, 200 mg.L-1) were decreased to (260 +/- 8) and (289 +/- 10) pmol.L-1, respectively. Early glycosylated low-density lipoproteins (LDL) did not affect Dia level.

Conclusion: AGEP causes a robust stimulation of Dia signaling pathway in VSMC. Vitamin E and aminoguanidine attenuate the production of Dia.

Aim: To study the attenuation of multidrug resistance (MDR) by R-dl-verapamil (R-Ver) and the acute animal toxicity of R-Ver, and to compare these results of R-Ver with the results of dl-verapamil (Ver).

Methods: Cytotoxicity was determined by tetrazolium (MTT) assay. Cellular accumulation of doxorubicin (Dox) was measured by fluorescence spectrophotometry. Acute animal toxicity was tested by i.p. drug administration in BALB/c mice.

Results: R-Ver attenuated MDR of KBv200 cells to vincristine (VCR) and Dox. This attenuation ability was dose-related, and was also dependent on drug exposure time. R-Ver 1.25 mumol.L-1 increased the sensitivity of KBv200 cells to VCR (P < 0.01) with a 24-h period of drug exposure. R-Ver downmodulated MDR and increased cellular Dox accumulation of KBv200 cells as effectively as Ver, but possessed lower acute toxicity in BALB/c mice. While LD50 of Ver was 60 (49-73) mg.kg-1, LD50 of R-Ver was 166 (137-202) mg.kg-1.

Conclusion: R-Ver downmodulated the MDR to VCR and Dox at 1.25 mumol.L-1, and this effect on VCR can be realized with drug exposure duration of 24 h.

Aim: To study the effects of bambuterol (Bam) on bronchoconstriction in guinea pigs.

Methods: Bronchospasm induced by histamine aerosol, lung resistance (RL) and dynamic lung compliance (Cdyn) changes induced by ovalbumin aerosol in vivo, isolated resting lung parenchyma strips, and carbamylcholine-induced tracheal constriction in vitro in guinea pig were investigated.

Results: Bam dose-dependently prolonged the time to histamine-induced collapse, ED50 values (95% confidence limits) of Bam intragastric gavage (i.g.) after 1 h, 4 h, and 24 h were 0.74 (0.60-0.91), 0.75 (0.61-0.91) and 1.00 (0.77-1.30) mg.kg-1, respectively. Bam 2 or 10 mg.kg-1 i.g. 2 h before ovalbumin aerosol partly or almost completely inhibited bronchial challenge of ovalbumin-induced change of RL and Cdyn. Bam 0.1-1.0 mumol.L-1 gave a weak relaxation on isolated tracheal strips induced by carbamylcholine and failed to relax the isolated resting lung parenchyma strips in guinea pig.

Conclusion: Bam showed a long-acting bronchodilation by its slow metabolism in vivo.

Aim: To study the effect of moxonidine (Mox) on carotid sinus baroreflex.

Methods: By perfusing the carotid sinus in anesthetized rats, the functional parameters of baroreflex were measured. The femoral artery was perfused with constant flow and the change of perfusing pressure was recorded to determine the effect of Mox on vascular tone.

Results: Mox 32 and 100 mumol.L-1 shifted the functional curve of carotid sinus baroreflex to the right and upward, with the reduction in peak slope and in reflex decrease of mean arterial pressure, suggesting that Mox produced an inhibitory effect on baroreflex. The effect of Mox 100 mumol.L-1 on baroreflex was completely blocked by efaroxan 100 mumol.L-1. Mox increased vascular resistance.

Conclusion: Mox inhibits carotid baroreflex via its constrictive action on sinus wall.

Aim: To study actions of allitridi extracted from garlic on intracellular calcium in isolated rat brain cells.

Methods: Brain cells were isolated from newborn rat brain with Fura 2-AM measurements of intracellular Ca2+ concentration ([Ca2+]i).

Results: Allitridi 1-100 mumol.L-1 concentration-dependently blocked increases of [Ca2+]i caused by potassium chloride and sodium glutamate (Glu) with IC50 of 59.7 and 69.9 mumol.L-1 respectively. Allitridi 100 mumol.L-1 blocked norepinephrine (Nor)-induced [Ca2+]i elevation.

Conclusion: Allitridi is an effective agent for blocking the [Ca2+]i increase caused by potassium chloride, Nor and Glu.

Aim: To determine whether adenosine 5'-triphosphate (ATP) is released from the superior cervical ganglion (SCG) of rats and whether the release is regulated by presynaptic mechanism.

Methods: Using the luciferin-luciferase technique.

Results: Electric stimulation evoked the release of ATP from the rat SCG. Adenosine (100 mumol.L-1), P1(A1) purinoceptor agonist N6-cyclopentyladenosine (0.1 mumol.L-1), the muscarinic agonist oxotremorine (1 mumol.L-1), and 5-hydroxytryptamine (100 mumol.L-1) decreased the evoked release of ATP from the rat SCG. On the contrary, P1(A1) purinoceptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (10 nmol.L-1), P2 purinoceptor antagonist pyridoxal-5-phosphate-6-azophenyl-2',4-disulphonic acid (10 mumol.L-1), muscarinic antagonist atropine (1 mumol.L-1), alpha 2 adrenoceptor antagonist yohimbine (3 mumol.L-1), D2 dopamine receptor antagonist sulpiride (20 mumol.L-1), and histamine (100 mumol.L-1) increased the evoked release of ATP from the rat SCG.

Conclusion: ATP is released from the rat SCG and the release of ATP can be presynaptically modulated by P1(A1), P2, muscarinic, alpha adrenergic, D2, 5-HT, and H1 receptor agonists and antagonists.

Aim: To study the antagonistic effect of glutathione (GSH) on toxicity of PC3 cell induced by cyclophosphamide (Cyc) and acrolein (Acr) and on immunosuppressive actions caused by Cyc.

Methods: Splenocyte, PC3 cell proliferation and cell protein content were measured by tetrazolium (MTT) assay and Coomassie brilliant blue assay. Serum anti-SRBC hemolysin, agglutinin, and splenocyte proliferation were measured in normal and S-180-bearing mice. Tumors were weighed.

Results: Pretreatment with GSH 2 mmol.L-1 reduced splenocyte proliferation inhibition from 18.64%, 49.72% to 6.78%, 18.36% (induced by Cyc 1, and 5 mmol.L-1), and PC3 cell proliferation inhibition from 27.7%, 45.3%, and 74.6% to 14.6%, 18.8%, and 49.1% (induced by Cyc 1, 3, and 5 mmol.L-1), and from 62.6%, 85.4%, and 90.6% to 41.9%, 57.7%, and 86.4% (induced by Acr 10, 25, and 50 mumol.L-1), respectively. In normal mice, s.c. GSH 75 or 150 mg.kg-1 b.i.d. x 5 d after i.p. Cyc 40 mg.kg-1, the hemolysin and the splenocyte proliferation were higher than those in normal mice i.p. Cyc 40 mg.kg-1 alone. Hemolysin, serum agglutinin, and splenocyte proliferation in S-180-bearing mice given s.c. GSH 150 mg.kg-1 b.i.d. x 10 d after i.p. Cyc 40 mg.kg-1 were also markedly higher than those in S-180-bearing mice given i.p. Cyc alone. But, according to tumor weight, GSH did not interfere the antitumor activity of Cyc in S-180-bearing mice.

Conclusion: GSH exhibited protective effects against Cyc and Acr, but had no effect on the antitumor action of Cyc.