Effeets of Verapamil and Dittiazem on Contractions of Aorta and Gastro-Oesophageal Sphincier in Rats

The contraction responses induced with serotonin (5-M) irz a medium without Ca2 + showed a dese-dependent increase by acicling Ca2+ into the extracellular mediutn. This contraction due to external Ca2+ used has significantly been inhibited by verapamil and diltiazem added into the extracellular medium. Similarly, in an isolated gastro-oesophageal sphincter, in a medium containing no Ca2+ the contraction induced with acetylcholine (ACh) has alsa been increased with Ca2+ used at a cumulative concentration and significantly inhibited by either calcium antagonists. Findings indicate that veraparnil and diltiazem have inhibited the eniry of extracellular Ca2+ intr. the tissues.