刀豆蛋白A促进T淋巴细胞增殖与ClC-3蛋白的关系

目的　研究刀豆蛋白A(ConA)促进T淋巴细胞增殖与内源性ClC 3蛋白的关系。方法　免疫印迹 (Westernblot)法检测ClC 3蛋白表达 ;[3 H] TdR参入法观察ConA对细胞增殖的影响。结果　①T淋巴细胞上有内源性ClC 3蛋白表达 ,分子量约为 80ku ;②ConA可浓度依赖性地促进T淋巴细胞增殖 ;③ConA刺激T淋巴细胞 2 4、4 8、72h后 ,ClC 3蛋白表达均增加 ;刺激 4 8h后ClC 3蛋白表达增加最多。④ConA可浓度依赖性地增加ClC 3蛋白表达。结论　T淋巴细胞上存在内源性ClC 3蛋白表达 ;ClC 3蛋白可能参与了ConA诱导的T淋巴细胞增殖过程     

ClC-3反义寡核苷酸对ConA诱导的T淋巴细胞增殖的影响

目的　研究ClC 3蛋白在T淋巴细胞增殖过程中的作用。方法　采用脂质体转染技术 ,将寡核苷酸导入细胞 ,免疫印迹 (WesternBlot)方法分析ClC 3蛋白表达 ;[3H] TdR参入法观察ClC 3反义寡核苷酸对细胞增殖的作用。结果　①ClC 3反义寡核苷酸浓度依赖性地抑制ConA诱导的ClC 3蛋白的表达 ;②ClC 3反义寡核苷酸浓度依赖性地抑制ConA诱导的T淋巴细胞增殖。结论　ClC 3蛋白参与了ConA诱导的T淋巴细胞的增殖过程     

Ca~(2+)运动对α_1-肾上腺素受体引起内源性ClC-3氯通道表达的作用

目的　研究Ca2 +运动对α1 肾上腺素受体引起ClC 3氯通道表达的作用。方法　在A10细胞上 ,用RT PCR和Westernblot检测ClC 3mRNA和蛋白质表达情况。结果　苯肾上腺素 ( 10 μmol·L-1)和thapsigargin( 0 1μmol·L-1)可促进ClC 3mRNA和蛋白质的表达 ;SK&F963 65 ( 10 μmol·L-1)和genistein( 10 μmol·L-1)可抑制苯肾上腺素引起的ClC 3的表达 ,nifedipine( 10 μmol·L-1)无此作用。结论　在A10细胞上 ,通过钙池操纵性Ca2 +通道 (SOCC)的Ca2 +内流参与了α1 肾上腺素受体引起的内源性ClC 3氯通道的表达 ,而通过电压依赖性Ca2 +通道 (VDCC)的Ca2 +内流可能与此无关。蛋白酪氨酸激酶参与了ClC 3氯通道的表达     

大黄素增强SD大鼠脑基底动脉平滑肌细胞BKCa电流

目的 研究大黄素对SD大鼠脑基底动脉的影响.方法 应用压力型小动脉测量仪观察给予大黄素前后脑基底动脉直径的变化;应用全细胞膜片钳技术观察大黄素对离体的SD大鼠脑基底动脉平滑肌细胞电流的调节作用.结果 (1) 大黄素舒张脑基底动脉(P<0.05);(2) 大黄素呈电压依赖性增强脑基底动脉平滑肌细胞外向电流(P<0.05);(3)大黄素呈浓度依赖性增强脑基底动脉平滑肌细胞外向电流,10-7、10-6和10-5 mol·L-1 的大黄素分别增加脑基底动脉平滑肌细胞外向电流(+ 60mV)从(173±43) pA 到(226±36) pA、(266±54) pA和(303±71) pA (P<0.05);(4) 给予10-3 mol·L-1 的BKCa通道阻断剂四乙胺(tetraethyl ammonium;TEA)不仅取消了大黄素对脑基底动脉平滑肌细胞外向电流的增强作用,而且使外向电流减小到(61.2±6.5) pA,比对照组电流减小了(0.65±0.06)倍(P<0.01).结论 大黄素通过增强BKCa通道的开放促进钾离子外流从而舒张脑基底动脉血管.     

氯沙坦抑制ROS/ERK1/2信号途径减轻AGEs诱导的大鼠脑血管平滑肌细胞增殖

目的探讨果糖制备的糖基化终末产物(AGEs)对大鼠脑基底动脉血管平滑肌细胞(BASMC)的增殖以及氯沙坦对增殖的影响和机制。方法培养大鼠脑基底动脉血管平滑肌细胞,用CCK8法测定不同浓度(1,5,10μmol/L)氯沙坦对果糖制备的AGEs(200mg/L)预处理48h诱导血管平滑肌细胞增殖的影响。用western blotting检测AGEs以及氯沙坦处理后对ERK蛋白表达影响。结果 AGEs刺激血管平滑肌细胞增殖(0.827±0.069比0.364±0.052,P<0.01)。给予氯沙坦(5,10μmol/L)后,细胞增殖明显下降(0.658±0.064和0.381±0.058比0.827±0.069,P<0.01)。AGEs还使平滑肌细胞内活性氧簇(ROS)生成增多,并显著增加ERK1/2蛋白表达,氯沙坦则明显抑制ROS和ERK1/2蛋白水平。结论果糖制备的AGEs诱导脑基底动脉血管平滑肌细胞增殖,氯沙坦可能通过阻断AT1受体而抑制ROS和ERK1/2表达,减少平滑肌细胞的异常增殖。     

甲壳胺对AngⅡ所诱导的乳牛基底动脉平滑肌增殖的影响

本文采用血管紧张素Ⅱ（AngⅡ）所诱导的乳牛基底动脉平滑肌细胞（BAVSMCs)增殖模型，以MTT法观察甲壳胺对BAVSMCs增殖的影响[^3H]TdR掺入法观察甲壳胺对乳牛基底动脉平滑肌细胞DNA的合成，还观察了甲壳胺对乳牛基底动脉平滑肌细胞总蛋白的影响。结果表明：甲壳胺对AngⅡ所诱导的BAVSMCs增殖有浓度和时间依赖性抑制作用；可浓度依赖性抑制AngⅡ所诱导BAVSMCs的DNA合成增加作用；还可抑制AngⅡ所诱导BAVSMCs蛋白合成增多作用，提示甲壳胺可抑制AngⅡ所诱导的BAVSMCs增殖作用。     

反义ClC-3寡核苷酸促进thapsigargin诱导的PC12细胞凋亡

目的　研究反义ClC 3寡核苷酸对thapsigargin诱导的细胞凋亡的影响。方法　蛋白免疫印迹法检测ClC 3蛋白的表达 ;MTT法检测反义ClC 3寡核苷酸对TG诱导的细胞生长的影响 ;形态学方法、流式细胞仪和DNA琼脂糖凝胶电泳观察和分析PC12细胞在转染ClC 3反义寡核苷酸后 ,TG诱导的细胞形态、DNA含量的变化和DNA断裂的情况。结果　与对照组相比 ,反义ClC 3寡核苷酸呈浓度和时间依赖性地抑制ClC 3蛋白的表达 ;使TG诱导的PC12细胞存活率降低 ,凋亡程度加强 ,差异有显著性 ,而正义及随义ClC 3寡核苷酸对此没有影响。结论　反义ClC 3寡核苷酸对TG诱导的PC12细胞凋亡有促进作用。     

消化法培养大鼠脑血管平滑肌细胞

目的建立大鼠基底动脉平滑肌细胞培养的方法。方法取大鼠基底动脉,剪成约0.2mm的小段,用含胶原酶Ⅱ型(0.5g.L-1)、弹性酶(0.15g.L-1)、透明质酸酶Ⅳ-S型(0.5g.L-1)及脱氧核糖核酸酶Ⅰ型(0.1g.L-1)的消化液在37℃消化1h。而后用含20%FCS的DMEM/F12进行培养。结果原代培养3d后细胞可少量贴壁,1wk左右可传代,细胞传代成活率达97%。光镜和免疫细胞化学染色检测第4代细胞纯度为98%。结论与目前国内培养脑血管平滑肌细胞的方法相比,本方法操作简单,培养周期短,细胞纯度高。     

野百合碱对培养的肺动脉内皮细胞NO含量、eNOS蛋白表达及肺动脉平滑肌细胞收缩性的影响

目的研究野百合碱(monocrotaline pyrrole,MCTP)对培养的牛肺动脉内皮细胞(calf pulmonary artery endothelial cells,CPAEs)一氧化氮(NO)含量、内皮型一氧化氮合酶(eNOS)蛋白表达及肺动脉平滑肌细胞收缩的影响。方法采用荧光共聚焦激光显微镜检测培养的牛肺动脉内皮细胞的NO含量;Western blot检测eNOS蛋白表达;胶原凝胶实验分析肺动脉平滑肌细胞收缩性。结果经野百合碱处理的牛肺动脉内皮细胞NO含量和eNOS蛋白表达较对照组明显减少、肺动脉平滑肌细胞收缩性增强。结论MCTP可抑制eNOS蛋白表达,肺动脉内皮细胞NO产生受到抑制,使肺动脉平滑肌细胞收缩性增强,这些改变与肺动脉高压的形成可能存在一定关系。     

α—actin表达异常与脑血管痉挛的关系

目的观察蛛网膜下腔出血（SAH）后脑血管平滑肌细胞内肌动蛋白（α-actin）蛋白质表达的动态变化规律,探讨收缩蛋白表达改变在脑血管痉挛（CVS）中的作用,阐明CVS发生的分子机制。方法用兔脑基底动脉平滑肌细胞体外培养,将红细胞裂解产物氧合血红蛋白（OxyHb）加入细胞培养液中,建立快捷有效的CVS体外模型;用免疫印迹（Westernblotting）方法观察α-actin表达的动态变化。结果在加入OxyHb后第1、4天,α-actin表达上升到113.5％±16.3％和112.9％±14.8％,第7天α-actin表达下降到74.4％±9.1％,与对照组相比均有显著性差异（P＜0.01）。结论SAH后OxyHb作用早期α-actin表达上升,增强脑血管平滑肌的收缩能力,与CVS的发生、发展有关。OxyHb持续作用的后期能够影响平滑肌细胞的蛋白质合成能力,并影响平滑肌细胞的生存状态,导致持续性脑血管痉挛发生,且难以解痉。     

Volume‐regulated chloride channels and cerebral vascular remodelling

• 1 Transmembrane Cl^? transport through volume‐regulated Cl^? channels (VRCC) is implicated in cell cycle control and the proliferation of vascular smooth muscle cells (VSMC). In cerebrovascular VSMC, volume‐regulated Cl^? movement is enhanced with the severity of cerebrovascular remodelling induced by hypertension.
• 2 Expression of the ClC‐3 chloride channel, a potential molecular candidate for the VRCC, is significantly increased with the progression of VSMC proliferation, but is decreased in apoptosis.
• 3 In the present review, we summarize recent findings regarding the functional role of volume‐regulated ClC‐3 chloride channels in VSMC proliferation, apoptosis and cerebrovascular remodelling during the development of hypertension. In addition, we discuss the relationship between the channel and intracellular signalling pathways, including the production of reactive oxygen species and the phosphorylation of Akt.
• 4 Recent studies strongly suggest that VRCC/ClC‐3 is involved in the regulation of both cell proliferation and apoptosis. These findings suggest that ClC‐3 chloride channels may be potential new targets for the prevention of the cerebrovascular remodelling that occurs during the development of hypertension.

     

蛋白酪氨酸激酶抑制剂对脑血管平滑肌细胞Ca~(2+)池操纵性Ca~(2+)内流的影响

目的　研究蛋白酪氨酸激酶和蛋白酪氨酸磷酸酶抑制剂对牛脑血管平滑肌细胞 (CSMC)Ca2 + 池操纵性Ca2 + 内流的影响。方法　采用培养的CSMC ,在生物荧光双波长影像分析系统用Fura 2 /Am荧光探针测定单个细胞内游离Ca2 + 浓度。结果　 (1)蛋白酪氨酸激酶抑制剂 (genistein ,2 5 ,5 ,10 μmol·L-1)能浓度依赖性降低内皮素 1(ET 1,10 -7mol·L-1)刺激引起的CSMCCa2 + 内流 ,抑制率分别为5 6%± 2 .9%、2 5 6%± 3 9%、48 9%± 3 7% ;蛋白酪氨酸磷酸酶抑制剂 (vanadate ,2 ,4,8μmol·L-1)能浓度依赖性升高CPA刺激引起的CSMCCa2 + 内流 ,增加比率分别为8 2 %± 3 9%、18 8%± 4 9%、46 6%± 6 9% ;(2 ) genistein(2 5 ,5 ,10 μmol·L-1)能浓度依赖性降低ATP(10 μmol·L-1)刺激引起的CSMCCa2 + 内流 ,抑制率分别为 6 7%±2 6%、2 4 6%± 6 5 %、5 1 3 %± 6 9% ;vanadate (2 ,4,8μmol·L-1)能浓度依赖性升高ATP刺激引起的CSMCCa2 +内流 ,增加比率分别为 4 8%± 2 0 %、2 8 5 %± 4 6%、49 6%± 3 3 % ;(3 ) genistein (2 5 ,5 ,10 μmol·L-1)能浓度依赖性降低环匹阿尼酸 (Cyclopiazonicacid ,CPA ,10 μmol·L-1)刺激引起的CSMCCa2 + 内流 ,抑制率分别为 6 5 %± 3 0 %、2 2 5 %± 5 2 %、     

DDPH抑制血管平滑肌细胞增殖及对HSP70和P53的影响

采用内皮素建立培养的血管平滑肌细胞增殖模型，用氚－胸腺嘧啶核苷（［３Ｈ］－ＴｄＲ）参入法，流式细胞术，Ｗｅｓｔｅｒｎ及Ｎｏｒｔｈｅｒｎｂｌｏｔ杂交方法，观察了１－（２，６－二甲基苯氧基）－２－（３，４－二甲氧基苯乙胺基）丙烷盐酸盐（ＤＤＰＨ）对血管平滑肌细胞增殖的作用及对热应激蛋白７０ｋｄ（ＨＳＰ７０）及其ｍＲＮＡ和抑癌基因Ｐ５３表达的影响。结果发现：ＤＤＰＨ能逆转内皮素所致的［３Ｈ］－ＴｄＲ参入量增多，阻止血管平滑肌细胞由静止期（Ｇ０／Ｇ１期）进入ＤＮＡ合成期（Ｓ期）和有丝分裂期（Ｇ２／Ｍ期），并能逆转内皮素引起的ＨＳＰ７０及ｍＲＮＡ表达增强，Ｐ５３抑癌基因及ｍＲＮＡ表达减弱。提示：ＤＤＰＨ能抑制血管平滑肌细胞增殖，与ＨＳＰ７０及Ｐ５３的调控有关。     

Enhanced expression of contractile endothelin ET(B) receptors in rat coronary artery after organ culture

Endothelin-1 is a potent vasoconstrictor mediating its effects via two receptor subtypes, the endothelin type A (ET(A)) preferentially situated on smooth muscle cells, mediating vasoconstriction and endothelin type B (ET(B)) mainly located on endothelial cells, mediating vasodilatation. In cardiovascular disease and in organ culture in vitro, endothelin ET(B) receptors are up-regulated on smooth muscle cells. The objectives of the present study were to characterise the endothelin receptor-induced vasoconstriction and quantify the endothelin receptor mRNA levels and immunoreactivity in fresh and cultured rat coronary arteries. We demonstrate that endothelin-1 induces strong and equal concentration-dependent contractions in fresh and cultured segments from the left anterior descending coronary artery. Sarafotoxin 6c, an endothelin ET(B) receptor agonist, had negligible effect in fresh arteries but produced significant vasoconstriction after organ culture. The endothelin ET(B) receptor mRNA level and the receptor protein immunoreactivity were increased, whereas the level of endothelin ET(A) receptor mRNA was down-regulated but not its receptor protein immunoreactivity after organ culture. Pharmacological inhibition of endothelium-derived dilatory mediators did not influence endothelin ET(A) or ET(B) receptor-mediated vasoconstriction in fresh segments. In cultured arteries, inhibition of endothelial vasodilators potentiated the effect of sarafotoxin 6c. In conclusion, endothelin ET(B) receptor stimulation in cultured coronary arteries elicits vasoconstriction. This is likely not related to endothelial dysfunction with putative loss of its vasodilator components, but rather explained by the up-regulation of contractile endothelin ET(B) receptors on smooth muscle cells.     

DDPH对血管平滑肌细胞增殖及PDGF-B、bFGFc-sis、c-myc的影响

目的：观察１－（２，６－二甲基苯氧基）－２－（３，４－二甲氧基苯乙胺基）丙烷盐酸盐（ＤＤＰＨ）对血管平滑肌细胞增殖的作用及对生长因子ＰＤＧＦ－Ｂ，ｂＦＧＦ及其相关癌基因ｃ－ｓｉｓ，ｃ－ｍｙｃ表达的影响。方法：内皮素建立培养的ＶＳＭＣ增殖模型，氚—胸腺嘧啶核苷（３Ｈ－ＴｄＲ）参入法，流式细胞术，１９９７－０３－２３收稿，１９９７－０４－０４修回＊国家教委优秀年轻教师基金资助项目１同济医院心内科，武汉４３００３０作者简介：熊一力，女，４１岁，博士后钱家庆，男，６３岁，博士生导师，药理教研室主任，中国药理学会常务理事免疫细胞化学及Ｎｏｒｔｈｅｒｎｂｌｏｔ杂交方法测定。结果：ＤＤＰＨ能逆转内皮素所致的３Ｈ－ＴｄＲ参入量增多，阻止ＶＳＭＣ由静止期（Ｇ０／Ｇ１期）进入ＤＮＡ合成期（Ｓ期）和有丝分裂期（Ｇ２／Ｍ期），并能逆转内皮素引起的ＰＤＧＦ－Ｂ，ｂＦＧＦ抗原，ｃ－ｓｉｓ，ｃ－ｍｙｃｍＲＮＡ表达增强。结论：ＤＤＰＨ能抑制ＶＳＭＣ增殖，与生长因子及癌基因调控的分子生物学机制有关。     

细胞色素P450 CYP4A的组织和细胞表达特异性

目的确定细胞色素P450 CYP4A在组织和细胞水平表达是否具有特异性。方法采用Western印迹法分析细胞色素P450 CYP4A蛋白在培养的牛肺动脉内皮细胞、平滑肌细胞及牛肾动脉内皮细胞的表达;采用原位杂交法检测细胞色素P450 CYP4A mRNA在大鼠肺支气管内皮和血管内皮细胞的表达;以14C标记的花生四烯酸(AA)作为反应底物,用荧光高效液相色谱法(HPLC)通过检测牛肺动脉内皮细胞催化外源性AA生成20-羟基廿碳四烯酸(20-HETE)的反应,确定肺动脉内皮细胞是否存在细胞色素P450 CYP4A;将肺动脉内皮细胞破碎并用乙酸乙酯萃取,用荧光物质标记萃取物,用荧光HPLC检测内源性20-HETE,从代谢产物水平确定细胞色素P450 CYP4A的功能蛋白质表达。结果①Western印迹法分析结果表明,细胞色素P450 CYP4A蛋白在牛肺动脉内皮细胞和平滑肌细胞中均有表达,在肺动脉内皮细胞中的表达明显高于平滑肌细胞(积分吸光度值分别为10182±279,5249±167);在牛肾动脉内皮细胞中也有表达,但明显低于肺动脉内皮细胞的表达(积分吸光度值分别为12173±171,17863±207)。②原位杂交结果显示,细胞色素P450 CYP4A mRNA可在大鼠肺支气管内皮细胞和大鼠肺血管内皮均有表达。③用HPLC在牛肺动脉内皮细胞中检测到20-HETE,表明细胞色素P450 CYP4A在肺动脉内皮细胞存在。结论细胞色素P450 CYP4A有其特定的组织和细胞分布,在牛和大鼠肺脏动脉内皮细胞有高表达。     

Endothelin‐1 and Endothelin‐3 Regulate Endothelin Receptor Expression in Rat Coronary Arteries

In ischaemic hearts, endothelin (ET) levels are increased, and vasoconstrictor responses to ET‐1 are greatly enhanced. We previously reported that ET_B receptors are up‐regulated in the smooth muscle layer of coronary arteries after myocardial ischaemia–reperfusion and that the MEK–ERK1/2 signalling pathway is involved in ET_B receptor up‐regulation. Whether ETs are directly involved in receptor regulation has not been determined. We suggest that ET‐1 and ET‐3 alter the expression/activity of ET receptors in coronary vascular smooth muscle cells. Vasoconstrictor responses were studied in endothelium‐denuded coronary artery segments from rats that were subjected to experimental ischaemia–reperfusion or in organ‐cultured segments. Post‐ischaemic and cultured coronary arteries exhibited similar increased sensitivity to ET‐3. ET_A receptor‐mediated vasoconstriction was dominant in fresh and non‐ischaemic arteries. Organ culture significantly up‐regulated ET_B receptors and down‐regulated ET_A receptor expression. Co‐incubation with ET‐1 (1 nM) or ET‐3 (100 nM) induced further down‐regulation of the ET_A receptor mRNA, while the function and protein level of ET_A remained unchanged. ET‐3 (100 nM) further up‐regulated ET_B receptor mRNA and proteins but abolished ET_B receptor‐mediated vasoconstriction, suggesting a desensitization of ET_B receptors that was not observed with ET‐3 (1 nM). In conclusion, ET‐1, which is the most prevalent isoform in the cardiovascular system, induces down‐regulation of ET_A receptor expression without changing ET_A or ET_B receptor function or protein levels. Intermediate concentrations of ET‐3 had an effect that was similar to that of ET‐1, such that high concentrations of ET‐3 (100 nM) up‐regulated the ET_B receptor at the gene and protein levels but switched off the function of the ET_B receptors via desensitization.     

氯离子通道ClC-3研究进展

ClC 3氯离子通道广泛分布于组织器官和各种细胞 ,ClC 3氯离子电流呈外向整合电流 ,在正性电位通道灭活 ,0mV左右出现反转电位 ,通道的离子渗透选择性是I->Cl-,能被氯通道阻断剂DIDS、tamoxifen和细胞外ATP抑制 ,被PKC磷酸化调节 ,参与细胞容积调控     

The apoptotic effect of Zoledronic acid on the nasopharyngeal carcinoma cells via ROS mediated chloride channel activation

Zoledronic acid (ZA), a third‐generation bisphosphonate, has been applied for treatment of bone metastases caused by malignant tumors. Recent studies have found its anti‐cancer effects on various tumor cells. One of the mechanisms of anti‐cancer effects of ZA is induction of apoptosis. However, the mechanisms of ZA‐induced apoptosis in tumor cells have not been clarified clearly. In this study, we investigated the roles of chloride channels in ZA‐induced apoptosis in nasopharyngeal carcinoma CNE‐2Z cells. Apoptosis and chloride current were induced by ZA and suppressed by chloride channel blockers. After the knockdown of ClC‐3 expression by ClC‐3 siRNA, ZA‐induced chloride current and apoptosis were significantly suppressed, indicating that the chloride channel participated in ZA‐induced apoptosis may be ClC‐3. When reactive oxygen species (ROS) generation was inhibited by the antioxidant N‐acetyl‐L‐cysteine (L‐NAC), ZA‐induced apoptosis and chloride current were blocked accordingly, suggesting that ZA induces apoptosis through promoting ROS production and subsequently activating chloride channel.     

Serotonin induces pulmonary artery smooth muscle cell migration

The chronic phase of pulmonary arterial hypertension (PAH) is associated with vascular remodeling, especially thickening of the smooth muscle layer of large pulmonary arteries and muscularization of small pulmonary vessels, which normally have no associated smooth muscle. Serotonin (5-hydroxytryptamine, 5-HT) has been shown to induce proliferation and hypertrophy of pulmonary artery smooth muscle cells (PASMC), and may be important for in vivo pulmonary vascular remodeling. Here, we show that 5-HT stimulates migration of pulmonary artery PASMC. Treatment with 5-HT for 16h increased migration of PASMC up to four-fold as monitored in a modified Boyden chamber assay. Increased migratory responses were associated with cellular morphological changes and reorganization of the actin cytoskeleton. 5-HT-induced alterations in morphology were previously shown in our laboratory to require cAMP [Lee SL, Fanburg BL. Serotonin produces a configurational change of cultured smooth muscle cells that is associated with elevation of intracellular cAMP. J Cell Phys 1992;150(2):396-405], and the 5-HT4 receptor was pharmacologically determined to be the primary activator of cAMP in bovine PASMC [Becker BN, Gettys TW, Middleton JP, Olsen CL, Albers FJ, Lee SL, et al. 8-Hydroxy-2-(di-n-propylamino)tetralin-responsive 5-hydroxytryptamine4-like receptor expressed in bovine pulmonary artery smooth muscle cells. Mol Pharmacol 1992;42(5):817-25]. We examined the role of the 5-HT4 receptor and cAMP in 5-HT-induced bovine PASMC migration. PASMC express 5-HT4 receptor mRNA, and a 5-HT4 receptor antagonist and a cAMP antagonist completely blocked 5-HT-induced cellular migration. Consistent with our previous report that a cAMP-dependent Cl(-) channel is required for 5-HT-induced morphological changes in PASMC, phenylanthranilic acid, a Cl(-) channel blocker, inhibited actin cytoskeletal reorganization and migration produced by 5-HT. We conclude that 5-HT stimulates PASMC migration and associated cytoskeletal reorganization through the 5-HT4 receptor and cAMP activation of a chloride channel.