ISSN: 1300-0292
İndekslendiği Dizinler: SCIENCE CITATION INDEX EXPANDED
CINAHL, Index Copernicus,
Chemical Abstracts (CA),
Excerpta Medica / EMBASE
Dil: Türkçe, İngilizce
İçerik: Orijinal Araştırma, Derleme, Editöre Mektup, Olgu Sunumu, Tıp Eğitimi, Tıbbi Kitap İncelemeleri
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ORIGINAL RESEARCH ARTICLES |
Inhibitor Effects Of Verapamİl And Nİtrendİpİne Onserotonin Induced Contraction In Calf Coronary Artery
Ayşe Saide ŞAHİN*, Necdet Doğan**
* Yrd.Doç.Dr., Selçuk Üniversitesi Tıp Fakültesi Farmakoloji AD, ** Prof.Dr., Selçuk Üniversitesi Tıp Fakültesi Farmakoloji AD, KONYA
Purpose: In this in vitro study, coronary arteries of calf were used to compare the inhibitory effects of verapamil and nitrendipine on serotonine (5-HT) dependent contractions and to investigate the type of interaction between 5-HT and these two antagonists.
Materials and Methods: Strips were mounted in 25 ml organ baths containing Krebs-Henseleit solution at 37oC continuously gassed with 95 %02 and 5% CO2. To evaluate the vasodilator effects of verapamil and nitrendipine, contractions were induced by cumulative added 5-HT (10-9- 10-4 M) . After obtaining a maximum steady state response, verapamil (10-9-10-4 M) or nitrendipine (10-9-10-4 M) were administered according to the cumulative doses method. In the next series of experiments, second cumulative dose-response curves to 5-HT were obtained in the presence of verapamil (10-8 and 10-6 M) or nitrendipine (10-8 and 10-6 M). In the other groups, dose-response curves to 5-HT were obtained. The tissues were exposed Ca++-free (0.1 mM EGTA) and verapamil (10-6 M) or nitrendipine (10-6 M) was added to the bath. 5-HT (10-6 M) was added to the bath before cumulative administration of Ca++ (10-4-10-2 M).
Results: In the presence of 5-HT, there was no statistically significant difference between IC50, t1/2 and % maximum relaxating effects of Ca++-channel blockers, which were used in the study. In the presence of verapamil (10-8 and 10-6 M) or nitrendipine (10-8 and 10-6 M), dose-response curves of 5-HT were shifted to the right and maximum contractile responses of 5-HT were depressed. In Ca++-free medium, 5-HT caused contractions amounting to 31.6 ± 5.68% of the maximum response obtained by re-addition of Ca++. In Ca++-free medium, nitrendipine inhibited 5-HT responses, which return with Ca++, more effectively than verapamil.
Conclusions: These results suggest that, 5-HT-induced contractions of calf coronary arteries are significantly dely than verapamil and the type of interaction between 5-HT and these two antagonists is noncompetitive antagonism.Keywords: Coronary Vessels, Serotonin, Verapamil, NitrendipineTurkiye Klinikleri J Med Sci 2001, 21:31-36
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