Rabbits were anesthetized with Urethane. The arterial blood pressure was recorded from the femoral artery with a Statham P 23 dB transducer. A servo-controlled Harvard Apparatus piston pump was used to infuse Acetylcholine and Noradrenaline respectively. The infusion rate was varied sinusoidally from 0.001 HZ to 0.1 HZ. The procedure was performed with different mean infusion rates and different infusion amplitudes. The response of the arterial blood pressure to the drug was examined by using the Bode analysis. The goal of our study was to examine if the blood pressure response to the infusion of a vasoactive drug can be characterized by a frequency dependent dose-response relationship. We could show that in terms of the frequency dependence the response to Noradrenaline differs in a quite typical way from the response to Acetylcholine. For both substances we were able to determine a frequency dependent transfer function. In addition we could describe the nonlinearity of the dose-dependent response of the blood pressure separately by an equation derived from the law of mass action. From the Bode diagrams the equations of the transfer functions are derived. In order to test the precision of the method, these equations were used to reconstruct the transfer function. This test is especially sensitive with respect to the phase of the function. We found a quite good agreement between calculated and measured values. This is a proof for the suitability of the method.

Acetylcholine↗

PubMedDate not supplied

[Thiocyanate--a biologically active ion of veterinary and medical relevance].

Thiocyanate-ions are ubiquitous in living nature. They are important for the cell-function and the ongoing of vital functions. Therefore they are an essential factor in both, animal and human being. The Thiocyanate-ions are brought in alimentary but also built by the organism itself. Beneath the guarantee for many different body-functions Thiocyanate-ions are an important part of the immune response. To that belongs their involvement in H2O2-Thiocyanate Peroxidase-Systems. Furthermore Thiocyanate-ions are agents for cell-protection and for the repair-mechanism of the host in the struggle with toxic substances of germs. Therefore they also have a tumour-prophylactic effect. Thiocyanate-ions participate at physiochemical reactions which due the protein-conformation. There are hypothesis that a deficiency of Thiocyanate-ions may be a co-factor for causative agents of diseases such as Cystic Fibrosis and Transmissible Spongiform Encephalopathia. References for calculations of the alimentary balance are given, if deficiency of Thiocyanate-ions occurs. From the view of an optimal animal-feeding the sufficient alimentary supply of Thiocyanate-ions and their precursors is mentioned.

Animal Feed↗