Effects of melittin on isolated papillary muscles of guinea pig

Citation
Yl. Zhang et al., Effects of melittin on isolated papillary muscles of guinea pig, ACT PHAR SI, 22(8), 2001, pp. 697-700
Citations number
11
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Pharmacology & Toxicology
Journal title
ACTA PHARMACOLOGICA SINICA
ISSN journal
0253-9756 → ACNP
Volume
22
Issue
8
Year of publication
2001
Pages
697 - 700
Database
ISI
SICI code
0253-9756(200108)22:8<697:EOMOIP>2.0.ZU;2-2
Abstract
AIM: To investigate the effect of melittin (Mel) on papillary muscles of gu inea pigs. METHODS: Contraction of papillary muscles were examined by conve ntional method and action potentials (AP) were recorded by standard glass m icroelectrode technique. RESULTS: Mel (0.5, 3 mu mol/L) significantly incre ased the contractility of guinea pig papillary muscles while 5 mu mol/L exe rted dual action with a transient decrease followed by an increase of the c ontractility. Mel shortened the functional refractory period (FRP) at conce ntrations of 0.5, 3, and 5 mu mol/L and increased the automaticity induced by adrenaline (Adr) at 3 and 5 mu mol/L. Met shifted the duration-intensity curve upward at 3 mu mol/L. It shortened the action potential duration (AP D) of fast action potential (FAP), decreased the action potential amplitude (APA) and resting potential (RP) at 0.5 and 3 mu mol/L. As to slow action potential (SAP), Mel 0.8 mu mol/L shortened APD(20) and APD(50), and decrea sed ARA and RP. CONCLUSION: Mel increased the contractility and automaticit y of papillary muscles, shortened the FRP, decreased the excitability, shor tened the APD, and decreased APA and RP of AP.