[Role of calcium ions in the contractile effects of acetylcholine (experiments on the guinea pig vas deferens)].

The authors carried out experiments on isolated vasa deferentia, obtained from a guinea pig. Recordings of the isotonic contractile activity was made by means of a strain gauge. Ink records were made on graduated tape of miliampermeter Tesla. Acethylcholine was used in a concentration of 1 X 10(-5) M, but serotonine-in a concentration of 1 X 10(-5) M. Growing reduction of the values was observed very regularly in all experiments both in the serotonine and acethylcholine contractions of vas deferens after diminution of the content of calcium in the Krebs solution from 0,9 to 0,15 mM. Gradual recovery of the value of the spastic effects of the examined substances was observed after placing the isolated organ in Krebs solution with a normal content of calcium. In analogous role of calcium in the spastic effects of the two mediators there were also some differences in the dynamics on which this role was manifested. The authors discussed the significance of the external calcium for the realization of the contractile effects of acethylcholine and serotonine on vas deferens of a guinea pig.