Effects of Vanadate on the K´-contracture of Guinea=pig´s Pyloric :Antrum Kim, Choong-Soo, Koh, In-Song, Uhm, Dae-Fong and Rhee, Sang-Don Department of Physiology, College of Medicine, Chung-Ang University, Seoul 156-756, Korea
Effects of vanadate on the spontaneous contraction and the high K´-induced contracture of`guiiea pig´s pyloric antral smooth muscles were observed in the various Na´ and/or Ca" of bathing solutions. Following results were obtained;
1. Basal tension and developed tension of the spontaneous activity were increased by vanadate and the membrane potential tended to be depolarized.
2. Phasic contracture increased, tonic contracture decreased as the outside K´ concentration in-creased and the both components were increased by vanadate.
3. In the case of absence of K´ and/or Na´, the contracture were hardly developed and the spontaneous, rhythmic contraction were sustained.
4. Effects of vanadate on the K´-contracture and the CaZ+-sensitivity of the phasic and tonic components were prominent in the presence of´ Na´.
The above results suggested that vanadate would increase the voltage-dependent calcium cur-rent in smooth muscle cells of the pyloric antrum.
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