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We investigated the vegetative response of the heart rate in chicken embryos (Gallus gallus f. domestica) on D18 and D20 with 22 experimental groups, consisting of 8 chicken embryos in each case. After one hour recording baseline heart rate the drugs Isoproterenol, Metoprolol, Orciprenaline or Propranolol in low, middle or high dosage influenced the heart rate. The ECG was measured with silver silverchlorid electrods (method by DÖRNER). We observed strong inter-individual heart rate fluctuations. We solved this problems by examining the median heart rate values. This allowed us to compare the baseline heart rate with the heart rate of the second experimental hour.Significant heart rate modifications were detected after application of the betasympathomimetic drug Iso in high dosage as well as Orci in middle and in high dosage in embryos on D18 during the second experimental hour. However return to the baseline heart rate was achieved only in the experiment with middle dosage of Orci in embryos of D18. Also significant heart rate modifications were detected after application of Orci in the dosage of 0,1 mg Orci/egg in embryos of both ages. The modifications are tendentious more strongly than after application of Iso in the same dosage on embryos of both ages. Orci in the last dosage produces high efficiency and a reduction of side effects, therefore it is recommended to use Orci in the dosage of 0, 1 mg Orci/egg for the stimulation of heart rate with sympathomimetic drugs.Also significant heart rate modifications were detected after application of the betasympatholytic drug Meto in high dosage in embryos on D20 as well as Meto in middle dosage or Prop in high dosage at embryos on D18- Baseline heart rate was achieved by both experiments at different points in time. Embryos of both ages has significant heart rate changes after application of Prop in the dosage used in the past by Lewin (1998) and Promny (2000). Thus it is recommended to reduce heart rate of chicken embryos by the use it the sympatholytic drug Prop in the dosage of 0, 0 1 mg Prop/egg.New investigations are necessary for the reducing the load of the embryos during experiments and for the characterisation of the ß-1 adrenoceptors of the heart. Thisinvestigations should investigate the dose response of Meto using dosages between 0,005 and 0,01 mg.The work presented here extended the knowledge about dose response of special drugs on heart rate and carried out a contribution to further clarify the functional innervation of chicken hearts. The used ECG method cannot be recommended for the representation of the heart rate of chicken embryos during a period of 7 hours.