摘要
观察大鼠离体胃体环行肌和胃底环行肌不同的药理学特征,分析核苷及核苷酸类物质诱发胃体环行肌收缩反应的作用特点和受体机制。制备大鼠离体胃体环行肌和胃底环行肌标本,利用受体药理学技术观察药物诱发的收缩反应。在胃体环行肌KCl所致收缩反应与胃底环行肌无显著性差别;但是,CCh收缩胃体环行肌的EC50值[(0.45±0.15)μmol.L-1]显著高于胃底环行肌[(0.20±0.09)μmol.L-1,P<0.01]。5-HT和His收缩两种标本的EC50值无显著差异(P>0.05);但是,在胃体环行肌5-HT和His产生收缩反应的Emax值[(0.81±0.26)和(0.88±0.27)g]显著小于胃底环行肌[(2.67±0.61)和(1.90±0.68)g,P<0.01]。在预收缩胃体环行肌,ATP(0.1～3000μmol.L-1)诱发浓度依赖性收缩反应,未见舒张反应;在预收缩胃底环行肌标本,同浓度ATP诱发先舒张后收缩的双相反应,并呈浓度依赖性。ATP、UTP、ADP、2-MeSATP和α,β-MeATP浓度依赖性诱发大鼠胃体环行肌收缩反应,2-MeSATP的EC50值为(7.2±5.2)nmol.L-1比Ach[(3.47±1.20)μmol.L-1]低500倍;各药物产生收缩反应的效价序列为:2-MeSATP>>ADP>ATP=UTP>α,β-MeATP>>腺苷。酚妥拉明、普萘洛尔、阿托品及河豚毒素不影响ATP和UTP诱发的胃体环行肌收缩反应。研究结果表明,大鼠胃体环行肌的药理学特征明显不同于胃底环行肌;核苷酸类物质通过某种特殊的P2Y受体介导胃体环行肌收缩反应,是调节胃体环行肌收缩功能的重要介质。
This study is to observe the difference in pharmacological characteristics between circular smooth muscles of rat isolated gastric body and gastric fundus, and to investigate the effects of nucleoside and nucleotide on circular smooth muscle of the rat gastric body and the involved receptors. Circular muscle strips of the rat gastric body and gastric fundus were prepared, and contractile responses to agonists were investigated with a technique of drug-receptor interaction in functional system. There was no significant difference between the circular muscle strips of the gastric body and gastric fundus in the responses to KCl, and no difference in EC50 values of contractile responses for 5-HT and His between the two kinds of preparations （P 〉 0.05）. However, Emax values of contractile responses to 5-HT and His [（0.81 ± 0.26） and （0.88 ± 0.27） g] in gastric body were significantly smaller than those in gastric fundus [（2.67 ± 0.61） and （1.90 ± 0.68） g, P 〈 0.01], and EC50 value of CCh produced contractile response [（0.45 ± 0.15） μmol·L^-1] in gastric body was significantly higher than that in gastric fundus [（0.20 ± 0.09） μmol·L^-1, P 〈 0.01]. In precontracted circular muscle strips of the gastric body, ATP （0.1-3 000 μmol·L^-1） produced only a contractile response concentration-dependently, but the same concentration of ATP induced a biphasic response （relaxation followed by a contraction） in precontracted circular muscle strips of the gastric fundus. ATP, UTP, ADP, 2-MeSATP and α, β-MeATP produced contractile responses concentration-dependently in circular muscle strips of the rat gastric body. The EC50 value for 2-MeSATP [（7.2 ± 5.2） nmol·L^-1] was about 500 times lower than that for Ach [（3.47 ± 1.20） μmol·L^-1]. The rank order of potency for the contraction was 2-MeSATP〉〉ADP〉ATP=UTP〉α,β-MeATP〉〉adenosine. The contractile responses to ATP and UTP were not significantly affected by phentolamine, propranolol, atropine or tetrodotoxin. In conclusion, there is a significant difference in pharmacological characteristics between the circular smooth muscles of the rat gastric body and gastric fundus and nucleotides might be important mediators responsible for the contraction via a specific P2Y receptor in circular smooth muscle of the rat gastric body.
出处
《药学学报》
CAS
CSCD
北大核心
2009年第5期473-479,共7页
Acta Pharmaceutica Sinica
基金
河北省自然科学基金资助项目(C2006000802)
关键词
胃体
胃底
环行肌
核苷酸
P2受体
gastric body
gastric fundus
circular muscle
nucleotide
P2 receptor
